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Feasibility of Geoexchange Systems in BC Agricultural and Agri-food Operations July 2012

B.C. Ministry of Agriculture

Agricultural and Agri-food Renewable Energy Feasibility Studies Project

JDQ Engineering Limited

Geoexchange Feasibility in Agricultural and Agri-food Operations


Acknowledgements

Funding for this project was provided by Growing Forward, a federal-provincial-territorial initiative promoting a profitable and innovative agriculture, agri-food and agri-products industry in Canada. The committee would like to express thanks to the agricultural producers who volunteered to participate in this study. Report authored by: JDQ Engineering Limited In partnership with: Enerficiency Consulting Altum Engineering Ltd. Prepared for: Innovation and Industry Development Branch, BC Ministry of Agriculture (AGRI) Project Steering Committee: Colleen Colwell, Ministry of Agriculture Matt Dickson, ARDCorp Lisa Levesque, Ministry of Agriculture Ian McLaughlin, Ministry of Agriculture Bob Paul, Ministry of Agriculture Mark Raymond, Ministry of Agriculture Mark Robbins, Ministry of Agriculture Philip Bergen, Agriculture and Agri-Food Canada Geoff Turner, Ministry of Energy and Mines Standard Limitations This report was prepared for the BC Ministry of Agriculture. Any use of this report by a third party or any reliance on or decisions made based on this report, are the responsibility of those third parties. JDQ Engineering Limited accepts no responsibility for damages, if any, suffered by any third party as a result of decisions made or actions taken based on this report. The analysis and calculations presented in this report are provided for purposes of supporting preliminary evaluations. Note that the calculations presented herein are based on various estimates and assumptions. As such, further site-specific investigations and energy analyses may be required to refine the analyses prior to preparing a detailed design. Detailed designs that may arise from the findings of this report will need to be carried out by fully qualified practitioners, and installation of any such designs will need to be carried out by suitably qualified contractors. In preparing this analysis we have relied in good faith on information provided or prepared by others, the accuracy of which we cannot attest to. The Government of Canada, the Government of British Columbia and ARDCorp or its directors, agents, employees, or contractors will not be liable for any claims, damages, or losses of any kind whatsoever arising out of the use of, or reliance upon, this information.



Table of Contents

1.0 Executive Summary ........................................................................................................................... 2

2.0 About This Study ............................................................................................................................... 4

2.1 Purpose ......................................................................................................................................... 4

2.2 Intended Audience ........................................................................................................................ 4

2.3 How to Use This Report ................................................................................................................ 5

2.4 Process of Selecting Participants .................................................................................................. 5

2.5 Demographic Coverage of Selected Sites ..................................................................................... 5

2.6 Scope of Work ............................................................................................................................... 6

2.6.1 Feasibility Studies .................................................................................................................. 6

2.6.2 Theoretical Scenarios ............................................................................................................ 7

2.6.3 Identifying Benchmarks ........................................................................................................ 8

3.0 General Geoexchange Principles ...................................................................................................... 9

3.1 Moving Heat Rather Than Creating It ........................................................................................... 9

3.2 Tapping Renewable Heat in the Ground ....................................................................................... 9

3.3 Geoexchange in Agricultural Settings ......................................................................................... 11

3.4 Common Misconceptions ........................................................................................................... 11

3.5 The Importance of a Site Suitability Assessment ........................................................................ 13

3.6 Geoexchange Greenhouse Gas (GHG) Savings ........................................................................... 13

4.0 Assumptions and Caveats ............................................................................................................... 14

4.1 Project Economics ....................................................................................................................... 14

4.2 System Scale and Technology Parameters ................................................................................. 15

5.0 Regulations, Permitting and Approvals .......................................................................................... 17

5.1 Regulatory Approval Process, Bodies and Agencies ................................................................... 17

5.2 Regulatory Restrictions and Limitations ..................................................................................... 17

5.3 Guidelines ................................................................................................................................... 17

6.0 Other Barriers to Development ...................................................................................................... 18

7.0 Participating Site and Theoretical Scenario Summaries ................................................................. 19

7.1 Site A – Artificially Lit Greenhouse with CO2 Enrichment ........................................................... 19

7.1.1 Site Feasibility ..................................................................................................................... 19

7.1.2 Theoretical Scenario Feasibilities ........................................................................................ 20

7.2 Site B – Seasonal Greenhouse without Artificial Lighting or CO2 Enrichment ............................ 21



7.3 Site C – Poultry Broiler Farm ....................................................................................................... 22





7.4 Site D – Poultry Processing Facility ............................................................................................. 23



7.5 Site E – Closed-Loop Aquaponic Facility ..................................................................................... 25



8.0 Benchmarking ................................................................................................................................. 27

8.1 Characteristics of Profitable Geoexchange Systems ................................................................... 27

8.1.1 Annual Heating and Cooling Requirements ........................................................................ 27

8.1.2 Energy Costs ........................................................................................................................ 28

8.1.3 Available GHX Options ........................................................................................................ 28

8.1.4 Interior Distribution Systems .............................................................................................. 30

8.2 Incentives for Currently Unprofitable Scenarios......................................................................... 30

8.2.1 Renewable Heat Incentives ................................................................................................. 30

8.2.2 Capital Cost Sharing ............................................................................................................ 30

9.0 Self Assessment Guide .................................................................................................................... 32

9.1 Estimating Potential Savings ....................................................................................................... 32

9.2 Predicting Site Suitability ............................................................................................................ 34

10.0 Geoexchange Technology Vendors ................................................................................................. 36

11.0 Conclusions ..................................................................................................................................... 37

APPENDIX A: Detailed Geoexchange Feasibility Study Results.................................................................A38

Site A: Artificially Lit Greenhouse with CO2 Enrichment.............................................................A38 Site B: Seasonal Greenhouse......................................................................................................A59 Site C: Poultry Broiler Farm........................................................................................................A77 Site D: Poultry Processing Facility...............................................................................................A95 Site E: Aquaponics Facility........................................................................................................A117

APPENDIX B: Utility Rates Used.............................................................................................................B144 APPENDIX C: Theoretical Scenario Evaluations.....................................................................................C147


JDQ Engineering Limited 1

Abbreviations AGRI Ministry of Agriculture ALC Agricultural Land Commission BC British Columbia BGS Below ground surface BH Borehole BTU British Thermal Unit CO2 Carbon Dioxide CPI Chabot Profitability Index DHW Domestic Hot Water DOE2 DOE2 Energy Modelling Software EWT Entering Water Temperature GHG Greenhouse Gas GHX Ground Heat Exchanger GJ Gigajoule GSHP Ground Source Heat Pump GW-GHX Groundwater Production / Injection Well Pair GHX H-GHX Horizontal Trenched GHX HX Heat Exchanger IRR Internal Rate of Return kW Kilowatt kWh Kilowatt Hour MBH 1,000 BTU/h MBTU 1,000,000 BTU MOE Ministry of Environment MUA Make Up Air MW Megawatt (1,000kW) MWh Megawatt Hour MWhth Megawatt Hour Thermal OAT Outdoor Air Temperature RHI Renewable Heat Incentive SWH Service Water Heating USgpm US Gallons per minute V-GHX Vertical Borehole GHX



1.0 Executive Summary This study was completed to evaluate the feasibility of installing geoexchange heating and cooling technology for agricultural and agri-food operations in British Columbia. Detailed feasibility studies were completed for five participating operations (including two greenhouses, a poultry broiler farm, a poultry processing facility, and a closed-loop aquaponic operation) distributed throughout the province. Each facility was visited to meet the owner/operators, observe operational function of the facilities, evaluate site setting and conditions, and examine suitability of potential ground heat exchanger (GHX) options. Following the visits, detailed energy analyses were completed to identify potential energy and greenhouse gas savings opportunities that could result from developing geoexchange systems at each of the facilities. Economically viable geoexchange development opportunities were identified for three of the five facilities (two greenhouses and the poultry processing facility). The assessments were also used to generate 70 different scenarios with varying climate conditions, base-case fuel sources and rate-structures, and GHX options. The economic viability of each of these scenarios was evaluated to determine common conditions that lead to profitable and unprofitable applications of geoexchange technology. Of the 70 scenarios evaluated, 63% are considered profitable, 11% are profitable but do not meet the target profitability threshold, and 26% are not profitable under current conditions. The key attributes that influence profitability in the scenarios evaluated are:

Heating and cooling load duration In all scenarios, the capacities of the proposed geoexchange options were selected in an effort to optimize the operating time of the systems. However, different operations inherently have different heating load durations. Those with longer duration heating requirements, including relatively continuous process heating requirements and summer heating loads, are the most likely to be profitable. Examples of this type of operation would be a heated greenhouse operating for 12 months of the year with crop heating pipes used through the summer, or a processing facility that has high hot water demands all year long.

Current energy source Geoexchange systems usually involve switching a large portion of annual energy costs away from fossil fuel combustion to electricity that is required to drive the heat pump process. Therefore, the relative costs of fossil fuels and electricity have a strong effect on the profitability of these projects. For example, 32 of 35 propane base-case scenarios were profitable compared to only 11 of 33 natural gas base-case scenarios. The current low price of natural gas (approximately $7.50/GJ for FortisBC Gas 3 Commercial service) significantly limits the types of geoexchange systems that are economically viable.

When electric resistance heating is the base case, higher electrical rates increase the profitability of geoexchange systems. In the two scenarios with an electric resistance base case, geoexchange systems were profitable at electrical rates of $0.029/kWh and $0.033/kWh.

Availability of low cost GHX options GHX cost estimates ranged by an order of magnitude for some scenarios, highlighting the key role site-specific characteristic can play in project economics. The most profitable scenarios occur where groundwater and horizontal GHX options are available. The least profitable scenarios occur where only vertical borehole GHX options (typically the most expensive type of



GHX) are viable. However, several vertical borehole GHX scenarios were profitable when favourable load duration, base-case fuel, and adaptable interior distribution conditions exist.

Adaptability of existing heat distribution systems Some existing heat distribution systems are more easily adapted to geoexchange systems than others. Low temperature hydronic heating systems, such as radiant floors that require supply water temperatures below 55 °C, are often easily adapted to a geoexchange system with little or no changes to the existing distribution system. High temperature hydronic heating systems designed for supply water temperatures above 55 °C may not provide the required heat output at the fluid temperatures that can be achieved by the ground source heat pumps (GSHPs) used in geoexchange systems. The output of hydronic heating systems is directly related to the system fluid temperature. Therefore in these cases, either the capacity of the GSHPs can be selected to match the existing distribution system output at a lower supply temperature, or the existing distribution system must be modified to match the desired GSHP capacity. In other cases, such as electric baseboard heating or distributed unit heaters, expensive additions to the distribution system are required to make geoexchange possible. The extra expense to modify existing distribution systems or to install new ones lowers the overall profitability of these scenarios.

These results were used to develop a Self Assessment Tool to help other farm operators predict the potential viability of a geoexchange system for their own operations. The current cost sharing incentive (30% of eligible costs to a maximum of $50,000) available for geoexchange systems through the Canada-British Columbia Environmental Farm Plan – Beneficial Management Practices Program was compared to the capital incentives required for 26 of the scenarios (37%) that were below the target profitability threshold to become economically attractive. The current incentive level appears to be well suited for encouraging investment in projects that are not quite economically attractive enough on their own, without promoting investment in poor applications of geoexchange technology.



2.0 About This Study 2.1 Purpose

This study was completed as part of the Ministry of Agriculture’s Climate Action Plan to provide on farm actions related to greenhouse gas (GHG) mitigation and climate change adaptation. Feasibility studies were completed for five BC agricultural and agri-food operations interested in adopting commercially available geoexchange systems to meet heating and/or cooling needs. The purpose of these studies is three-fold:

To provide a thorough understanding of the feasibility of geoexchange heating and cooling technology at each participating agricultural and agri-food operation,

To inform the BC Ministry of Agriculture and other stakeholders regarding the wider opportunity for geoexchange technology in the agriculture sector through the development of economic and feasibility benchmarks, and

To develop tools based on the findings of the benchmarking analyses that allow BC agricultural and agri-food operators to conduct preliminary self assessments to determine the likelihood that a geoexchange system could be viable for their heating and cooling needs.

This work was guided by a Project Steering Committee comprised of representatives of the BC Ministry of Agriculture, BC Ministry of Energy and Mines, Agriculture and Agri-Food Canada, and BC Agricultural Research & Development Corporation (ARDCorp). 2.2 Intended Audience

This report is intended for agricultural and agri-food operators in BC interested in evaluating the potential viability of geoexchange space or process heating/cooling for their operations. It summarizes the results of geoexchange feasibility studies at five real operations, as well as 70 hypothetical scenarios to provide readers with a wide range of examples that illustrate the conditions that most commonly lead to viable projects and those that do not. This information can be used by owners to help predict the likely benefits and viability of geoexchange technology for their operations, and to determine if it is worthwhile to have a formal evaluation conducted for their site. This report is also intended to provide valuable information to industry and government about the relative feasibility of geoexchange technology to reduce greenhouse gas emissions in the agriculture and agri-food sectors in BC. For those geoexchange scenarios that are not currently economically attractive, the relative costs of fossil fuels and electricity that would lead to economic viability have been determined. The required capital assistance and renewable heat incentive (RHI)1 values that would make these scenarios economically attractive are also presented to provide industry and government with information that can be used in future decisions targeting GHG reductions in the agriculture and agri-food sectors.

1 A renewable heat incentive is a payment for generating renewable heat, similar to how a Feed-in Tariff is used for renewable

electricity generation. RHIs are paid at a predefined dollar amount per unit of heat produced and are typically stated as $/MWhth.



2.3 How to Use This Report

This report contains background information on geoexchange technology, detailed technical and economic feasibility assessments, benchmark conditions required for viability, and a self-assessment guide for potential geoexchange applications. It is not intended for all readers to read all sections. Most readers will benefit from reading General Geoexchange Principles (page 9) to become familiar with geoexchange capabilities, limitations, benefits, common misconceptions, and ground coupling options. Many readers may then wish to skip to the Self Assessment Guide (page 32) to quickly assess the likelihood that geoexchange will be an attractive option for their operation. Readers can then return to the detailed feasibility study (pages 19-26) that most closely matches their own operation and the Benchmarking section to more carefully evaluate the results most relevant to their situation. Readers will also find a summary of the self-assessment process in the Fact Sheet that has developed to compliment this report. 2.4 Process of Selecting Participants

Agricultural and agri-food operations were targeted to participate in the project in order to meet the following goals:

Representation from a cross-section of different types of agricultural operations

Representation from various agricultural regions across BC, including northern BC

Representation of different types of heating and cooling loads, such as animal barn heating and ventilation, process heating and cooling (e.g., dairy and aquaponics), controlled growing environments, farm residences, etc.

Operations with particularly intense energy demands and large GHG footprints

Operations that typically generate waste heat discharges in parts of the process while requiring heat in other parts of the process

Operations that are likely to represent a diversity of GHX options and ground conditions

If possible, both new construction or expansion, and retrofit opportunities A total of nine agricultural operations submitted applications to the project and five of these were selected for evaluation. 2.5 Demographic Coverage of Selected Sites

The five agricultural operations selected for evaluation included:

A. a greenhouse planning an expansion to year round operation with artificial lighting and CO2 enrichment;

B. a seasonal greenhouse without artificial lighting or CO2 enrichment;

C. a poultry broiler farm;

D. a poultry processing facility; and

E. a closed-loop aquaponic facility.



The geographic locations of these facilities are shown in Figure 1 and individual feasibility reports for each site are provided in Appendix A.

Figure 1. Location of agricultural operations selected for geoexchange feasibility studies

2.6 Scope of Work

This project included three major components – completing feasibility studies for five operations, using these studies as the foundation for evaluating feasibility under an additional 70 theoretical scenarios, and assessing the combined results to identify the common parameters and benchmarks of economically attractive opportunities that will allow other interested parties to gauge the likely viability of a geoexchange system at their operations. 2.6.1 Feasibility Studies Feasibility studies were carried out to meet the general requirements described in Professional Guidelines for Geoexchange Systems in British Columbia - Part 1 Assessing Site Suitability and Ground Coupling Options; Geoexchange BC, 2007.

E

B C A

D



The scope of work to examine the site-specific options for adopting geoexchange for each operation included:

conducting a site visit and reviewing operational and performance requirements with the owner;

modelling heating and cooling loads and energy consumption for the operation with DOE2 energy modelling software2;

interpreting site visit observations and relevant background documents including geological maps, water well completion and geotechnical reports (if available), to develop an understanding of soil and groundwater conditions at the site;

estimating key thermal properties of shallow and deeper earth materials below the site and assessing constructability of various types of GHX systems;

evaluating the technical and financial feasibility of applying geoexchange technology to the range of operational heating and cooling loads at the site and recommending the leading option(s);

developing a conceptual schematic design for the leading geoexchange option(s);

simulating the conceptual design in DOE2 to estimate energy and operational cost savings;

estimating the costs of installing the conceptual design and evaluating the financial viability of an investment in geoexchange technology; and

recommending next steps based on the feasibility assessment. Detailed individual site reports are included in the Appendices. 2.6.2 Theoretical Scenarios The results of the five feasibility studies were used to generate 70 theoretical scenarios by changing one or more of the following conditions:

Climate conditions – By varying the weather data used in the energy modelling software, we evaluated how annual energy requirements and geoexchange feasibility would change if the study sites were located in different parts of the province including the Lower Mainland, Southern Interior, and the Prince George regions.

Utility rates – Utility rate structures were selected to match the actual rates a facility would pay based on the location and predicted energy use patterns for each scenario. In total, ten different BC Hydro and FortisBC electrical rates, four FortisBC natural gas rates, and two propane rates are represented by the scenarios considered. Details of each rate structure are provided in Appendix B.

Site ground characteristics – We compared how differing ground thermal properties and available GHX options (see Section 3.2 on Page 9), and the resulting geoexchange construction costs in different regions of the province affect project economic viability.

2 DOE2 is full year (8,760 hour) computer simulation software developed by the US Department of Energy. It calculates heating and cooling loads and energy consumption for each hour of the year based on a description of the building surfaces and equipment, and a site weather file. DOE2 is the most widely used energy simulation software available, and allows for exceptional accuracy and flexibility.



A feasibility assessment was performed for each of the 70 theoretical scenarios using the same evaluation process as used for the 5 study sites. 2.6.3 Identifying Benchmarks The site feasibility assessments and 70 theoretical scenarios were compared to determine the key parameters and values that affect the economic viability of geoexchange systems. For those scenarios that were not economically attractive, we determined what electrical and fossil fuel energy costs, project capital costs, RHI, and capital cost sharing would be required for project viability. These results were used to develop a Self Assessment Tool (Page 6) to help owners predict the potential viability of a geoexchange system for their own operation.



3.0 General Geoexchange Principles 3.1 Moving Heat Rather Than Creating It

Geoexchange systems can be exceptionally efficient because they use energy to move heat rather than converting energy into heat as conventional heating systems do. They do this with a ground source heat pump (GSHP). Household refrigerators, air conditioners, commercial chillers and GSHPs all work on the same principle. They use a refrigerant evaporation/compression cycle to absorb heat from one location, raise its temperature, and release it at another location. Energy is used to run the refrigeration cycle and that energy also gets released as heat. By moving heat instead of converting electrical or chemical energy into heat, geoexchange systems can often provide space and process heating more efficiently than conventional combustion or electric resistance heating systems. Well designed geoexchange systems can often deliver 3 or 4 units of heat for each unit of energy used to run the system (see Measuring Efficiency side bar). The efficiency of any refrigeration equipment is influenced by the temperature difference between the source of heat being absorbed and the sink to which the heat is being released (often called temperature lift). For example, a refrigerator uses less energy than an equivalently sized freezer, and an air cooled chiller uses less energy on cold winter days than in the height of summer. It takes more energy to pump heat up a larger change in temperature much the same as it takes more energy to pump water up a larger change in elevation. Geoexchange systems aim to maximize efficiency by reducing the required temperature lift. The ground makes an efficient heat source in winter because the undisturbed earth temperature is warmer than average winter air temperatures. It is also a good heat sink for summer cooling because the ground is cooler than average summer air temperatures. To achieve these benefits GSHPs are coupled with one of several possible types of ground heat exchanges (GHXs). 3.2 Tapping Renewable Heat in the Ground

The ground heat harnessed by geoexchange systems is renewable heat. Most of the heat captured by geoexchange is solar heat absorbed by the earth’s crust, while a smaller portion is core geothermal heat.3 The ease with which heat can be moved from or to the ground with a GHX is dependent on the thermal properties of the surrounding soils. Soils with high thermal conductivity such as dense rock or saturated gravel require smaller GHXs than soils with low thermal conductivity such as dry sand and silts

3 Note however, that geoexchange systems are distinct from geothermal energy stations that are used to generate electrical power by using the high temperatures found deep (often thousands of meters) within the earth.

Measuring Efficiency The efficiency of a heat pump is often measured by its Coefficient of Performance or COP.

A heat pump with a COP of 3.5 delivers 3.5 units of heat for each unit of energy consumed. For comparison, high efficiency boilers typically have a COP near 0.9. They only deliver 0.9 units of heat for each unit of energy they consume because some of the heat generated through combustion is lost in the exhaust gases. Electric boilers, baseboards, and furnaces that use resistance elements have an effective COP of 1.0.



to achieve the same heat transfer. Ground temperature, depth of GHX piping and the degree of ground water movement also affect the required GHX size for a given heat transfer rate. GHXs can take many forms, but they all belong to one of two following categories:

Closed-loop GHX systems rely on conductive heat transfer between the earth and a heat exchange fluid circulated in a closed network of underground piping. Closed-loop GHXs can be installed in horizontal trenches, vertical boreholes, large excavations, or submerged in large water bodies.

Open-loop GHX systems rely on the direct transfer of groundwater or surface water to a GSHP. After passing through the GSHP, water is returned to the same aquifer or water body from which is was drawn.

The three most common types of GHX are:

Vertical borehole GHX (V-GHX). This method involves drilling a network of boreholes that are each typically 45 m to 120 m deep. Two pipes with a u-bend connection at the bottom are placed in each borehole and heat exchange fluid is circulated through this closed-loop piping network. V-GHXs are the most versatile GHX configuration and can be adapted to the widest range of settings. The reduced space requirements of V-GHXs relative to other closed-loop GHX options allows construction of V-GHXs at many smaller sites or in situations where there is a preference to minimize surface disturbances at the site. In some cases, some or all of a V-GHX can be installed under a new structure with careful planning and coordination. However, the V-GHX method is typically the most expensive option when other options are available.

Groundwater Open Loop

Horizontal Closed Loop

Vertical Closed Loop

Surface Water Closed Loop

Surface Water Open Loop



Horizontal trenched GHX (H-GHX). This method involves installing a closed-loop network of piping in a series of excavated trenches. Piping is typically installed at depths of 1.2 m to 1.8 m below ground surface (or up to 3.0 m in northern or high elevation climates). Because the piping is laid horizontally rather than installed vertically, the H-GHX method requires a much larger ground area to provide the same heat exchange capacity as a drilled V-GHX. Consequently, horizontal systems are limited to applications where large open areas are available relative to the building footprint.

Groundwater Production / Injection Well Pair (GW-GHX). Groundwater open-loop systems typically move groundwater from a producing well, through a heat exchanger, and then return the groundwater at a reduced temperature (in heating mode) back to the aquifer through an injection well. These systems can be very cost-effective in settings where high rates of high quality water can be produced sustainably. However, the appropriate site conditions for open-loop groundwater systems are relatively rare. Furthermore, these systems typically require more diligent attention to maintenance and incur higher maintenance costs than closed-loop systems, particularly if the groundwater is highly mineralized or is otherwise not of high quality.

3.3 Geoexchange in Agricultural Settings

Many agricultural settings have the right conditions for a cost-effective geoexchange system. The costs to install a GHX are often the largest component of geoexchange system costs and therefore the available GHX options often determine overall project viability. Agricultural operations are more likely to be suited to low cost GHX options than other typical commercial and residential settings. In particular, agricultural operations often have:

large open spaces that may be suitable for low cost installation of a horizontal GHX; and

existing water wells or other water sources used for irrigation, cleaning, watering livestock, etc. In some cases existing wells can perform double-duty and be used as the production well for an open-loop GW-GHX. In these situations, only an injection well will need to be drilled, thereby reducing the cost of a GW-GHX because half of the system requirements are already in place.

Many agricultural and agri-food operations also have concurrent heating and cooling loads. When an operation or facility needs cooling and heating at the same time – for example, dairies need to both chill milk and generate hot wash-water, while other types of operations require refrigerated storage and space/water heating – heat removed during the cooling process can be moved to supply the heating requirements. This form of heat recovery can often be achieved with a relatively small GHX or no GHX at all, making it a low cost opportunity to significantly reduce energy consumption, GHG emissions, and utility bills. 3.4 Common Misconceptions

There is a common misconception that the temperature of the soil/rock surrounding a GHX remains constant despite the movement of heat in and out of the ground. As a result, there is a widely-accepted perception that geoexchange systems always operate at a consistent performance level because they supposedly tap an “unlimited availability of heat at a constant ground temperature”.



Unfortunately, this perception is false and often leads to inappropriate applications of geoexchange technology. In reality, the ongoing thermal interaction between the heat pump system and the GHX causes the temperature of the soils near the GHX to vary with time. The soil and thus the GHX temperature varies in response to both the rate of heat transfer and the cumulative quantity of heat extracted from or rejected into the earth. GHXs can also be quite sensitive to the relative balance of the heating and cooling loads. Facilities with heating only or cooling only systems will usually require a larger GHX than similar facilities with an annual balance of heating and cooling needs. Careful evaluation of heating and cooling loads, site-specific soil thermal properties, and the available GHX configuration options is required to size and design a GHX that will operate sustainably within an acceptable temperature range. Careful consideration should also be given to the desired use of the area in which a GHX is installed. For example, if crops are to be grown immediately above the GHX, the design should take into account the soil temperature range acceptable for crop growth and adjust the GHX size and/or depth accordingly. Additional consideration should also be given to the potential soil disturbance associated with installation of different GHX configurations such as the mixing of soil strata during excavation or potential compaction from heavy equipment. Another common misconception is that geoexchange systems must be sized to provide the full peak heating requirements of a facility. Sizing to the full peak load is possible, but requires large GHXs which often make this option uneconomical. Because intense peak loads only occur for short durations, heat pump and GHX capacity intended to meet the most intense portion of the load will be idle for the vast majority of the hours in a typical year. Because this portion of the system capacity rarely operates, it has limited opportunity to earn a return on investment. Geoexchange systems are therefore usually only sized to meet the full peak loads in situations where very low cost GHX options are available, or where other unusual conditions exist. Geoexchange systems in commercial and industrial applications are more commonly sized to handle a smaller base-load portion of the peak load that occurs for longer portions of the year. Depending on the specific load profile of a facility, the optimal geoexchange capacity may be anywhere from 5% to 70% of the peak load. Due to the annual distribution of heating loads and the often very short duration of peak loads, geoexchange systems sized to only a portion of the peak load can often deliver the vast majority of the annual heat required.

Geoexchange Heat Pump Capacity Ratings

The rate that a geoexchange heat pump can move heat, or its capacity, is often defined in the same manner as air conditioners and chillers, using “nominal tons”.

A nominal ton is formally defined as 12,000 Btu/hr (the rate of heat extraction required to produce one ton of ice in one 24 hour period).

However, due to the different temperature lift required in cooling and heating modes, GSHPs typically have 12,000 Btu/hr cooling capacity per nominal ton, but only 8,000 to 10,000 Btu/hr heating capacity per nominal ton. Therefore a heat pump with a capacity of 20 nominal tons has the ability to move 240,000 Btu/hr cooling capacity and 200,000 – 160,000 Btu/hr heating capacity.



3.5 The Importance of a Site Suitability Assessment

Because of the tectonic and glacial history in BC, ground conditions in BC are more variable than virtually anywhere else on earth. The geological structures at some locations lend themselves to low-cost, high performance GHX systems; whereas other settings cause challenging, high-cost, low performance, and poor constructability conditions. As a result, the cost for a given GHX capacity can vary by more than an order of magnitude from one site to another. See section 8.1.3 Available GHX Options for a detailed discussion of factors affecting GHX costs. GHX construction costs can range from about $1,000 per nominal ton at the low end to $10,000 or more per nominal ton at the upper end. This large range is attributed to many factors including:

GHX type: different installation methods with varying cost;

relative balance of heating and cooling loads: unbalanced loads in which significantly more heat is extracted from the GHX in heating mode than is rejected to the GHX in cooling mode (or vice versa) require bigger, more expensive GHXs;

site-specific soil and rock conditions: localized ground conditions can be challenging for drilling or trenching which can significantly escalate cost; and

Procurement processes: amount and type of information provided to prospective service providers and the type of process used to engage services can affect cost.

An objective evaluation of site-specific conditions and appropriate consideration of site-specific options can help identify opportunities for improving technical performance, reducing cost, and managing risk. GeoExchange BC, a non-profit industry association, has developed professional guidelines to address this important step in evaluating potential geoexchange opportunities (Professional Guidelines for Geoexchange Systems in British Columbia - Part 1 Assessing Site Suitability and Ground Coupling Options; Geoexchange BC, 2007). 3.6 Geoexchange Greenhouse Gas (GHG) Savings

Geoexchange systems can provide heat with a fraction of the Greenhouse Gas (GHG) emissions of conventional fossil fuel combustion. Geoexchange systems consume much less energy by moving heat rather than creating it, and in BC they are powered by electricity that has a very low GHG emission rate. This combination of excellent efficiency and fuel switching leads to GHG reductions of over 90% as shown in Table 1. Table 1. Greenhouse gas emissions reductions possible with geoexchange technology

Heating Source: Geoexchange COP = 3.0

95% Efficient Natural Gas Boiler

or Furnace

95% Efficient Propane Boiler or

Furnace

Geoexchange GHG Reduction

GHG emissions per 1,000 GJ of heat delivered (tonnes CO2e)

3.0 52.95 63.66 94.3% to 95.3%

http://www.geoexchangebc.com/



4.0 Assumptions and Caveats The data presented in this report (Section 7.0) have been determined based on a number of assumptions to make the results as generic as possible and relevant to most situations. These assumptions may or may not apply to all readers. Anyone assessing the likely suitability of geoexchange system for their operations should review these assumptions and account for any differences in their own evaluation. It is important to note that GHX options and installation costs are highly site-specific, and the size and range of costs presented here may not cover all situations. Therefore, the benchmarks presented in this report should be used as a guide for preliminary self-assessments. A formal site suitability assessment following GeoExchange BC’s Professional Guidelines is highly recommended before proceeding to the design and installation of a geoexchange system. 4.1 Project Economics

Capital costs presented in this report are preliminary estimates based on experience with similar projects. Capital costs represent the incremental cost of adding geoexchange to a heating or cooling system and do not include the costs for any equipment that would also be required for a standard or base-case scenario heating and cooling system. Actual capital costs may vary by region and available service providers. Energy costs have been estimated using hourly energy consumption estimates and actual electrical rate structures. Energy costs are presented as blended rates that include basic monthly rates, per unit charges ($/kWh, $/GJ), and any demand charges that may apply. A list of electrical and natural gas rate structures used is provided in Appendix B. The economic viability of each scenario was evaluated over a 25-year project life using the Chabot Profitability Index4 (CPI). The CPI method was developed by Bernard Chabot of France’s Agence de l’Environment et de la Maitrise de l’Energie to establish tariff rates that provide acceptable levels of profitability in the development of renewable energy projects. The CPI method was used to design France’s Renewable Energy System Feed-in Tariff (FIT), and has been used to make recommendations on tariff pricing for numerous FIT policies around the world, including Ontario’s Green Energy and Economy Act and FIT Program. A CPI of 0.3 is recommended by Chabot as the level required to promote investment and growth in the renewable energy sector. Although the desired level of economic reward will vary from owner to owner, a CPI of 0.3 was selected as the target threshold of economic viability for the scenarios assessed in this report. All economic calculations were based on the following criteria and assumptions:

A discount rate of 10% was used in net present value and CPI calculations, as it is presumed to be a reasonable expectation of return on investment in a renewable energy project. A discount rate of 5% was used to evaluate the value of capital grants required to meet the profitability target, to reflect the lower financial risks born by the owner.

4 CPI is defined as the project net present value divided by the present value of the capital investment. For additional information on the Chabot Profitability Index see: Background on the Cost of Generation and the Chabot PI Method

http://www.wind-works.org/PricingWorksheets/BackgroundontheCostofGenerationandtheChabotPIMethod.html



Net present value and CPI are based on 100% financing of incremental capital costs at a loan interest rate of 6%.

Project Internal Rate of Return (IRR) has been calculated for the project itself and does not include any financing costs. The IRR of a scenario with a calculated CPI of 0.3 will therefore be higher than the discount rate used in the CPI calculation which does include financing costs.

The useful life expectancy of a GHX is two to three times longer than the 25-year project evaluation period. Therefore, the residual value of the GHX (discounted installation cost) was included in the last cash flow (year 25) of the net present value calculation to reflect the longer service life of this infrastructure.

Tax implications of the project investment and financing have been estimated based on an assumed effective tax rate of 25% and include:

o Accelerated Capital Cost Allowance of 50% per annum available for geoexchange system costs; and

o deductions for interest paid on project financing.

All costs are estimated based on market conditions and utility rates prevailing in February 2012. Labour and capital equipment costs for service providers involved in GHX construction may vary with activity levels in other sectors that use these services, such as mining and other civil works. Significant changes in market conditions or utility rates will change the estimated profitability scores presented in this report.

An inflation rate of 2% and energy cost escalation of 4% were used for all scenarios (predicting future natural gas prices is much less certain than future electrical prices; however, we have used a common energy escalation rate for all energy sources).

Maintenance costs have been assumed to be equal between geoexchange and base-case scenarios and are not included in the incremental costs/savings calculations.

Possible cost sharing opportunities through the Canada-British Columbia Environmental Farm Plan Program for farm practices specified within the Beneficial Management Practices Program are not included in initial profitability calculations. The applicability of this funding source is discussed further in Benchmarking below.

For those projects that did not meet the threshold CPI, the value of each energy source and the capital cost were varied independently to determine the amounts required for profitability if all other parameters are held constant. The conditions required for profitability were calculated using the assumptions above. 4.2 System Scale and Technology Parameters

The optimal size of a geoexchange system can vary significantly from one setting to another (see Section 3.4 Common Misconceptions). In some cases the size of a geoexchange system is constrained by the area available to install a GHX, or the limits of an existing heat distribution system. In other cases the size can be selected to match obvious long duration loads that provide the highest pay back. And in yet others, the optimal size may depend on the funding available and the return on investment desired by the owner.



The geoexchange system(s) proposed in each feasibility study represents our recommendation for those specific circumstances. They are unlikely to be the optimal size in all circumstances, but represent a broad range of scenarios that are useful for comparison. Owners comparing these case studies to their own facilities should be aware that the optimal system size for their operations may vary based on site and operation specific conditions. In all cases we have used the following criteria in evaluating geoexchange options at each site:

GHX sized to provide minimum heat pump source entering water temperature of -1 °C for southern projects and -2 °C for northern projects

Heat pump hydronic supply temperature limited to 50 °C

Heat pump COP and performance characteristics from readily available heat pump models

Theoretical scenarios involving V-GHX options were evaluated for both good and poor drilling conditions to cover the potential range of V-GHX installation costs.

Commercially available heat pump models that can operate outside these temperature ranges are significantly more expensive than standard range equipment, but may be useful in certain circumstances.



5.0 Regulations, Permitting and Approvals 5.1 Regulatory Approval Process, Bodies and Agencies

Geoexchange systems must follow the same standard regulatory approval and permitting processes associated with conventional heating and cooling systems. These include those required by the Electrical Safety Authority, WorkSafe BC, BC Building Code, and building permit requirements of the local authority having jurisdiction. There are no regulatory approvals or permitting processes related specifically to geoexchange systems. However, excavation and drilling of ground heat exchangers must follow safety and environmental regulations protecting groundwater, surface water bodies, and other environmentally sensitive areas as listed below. 5.2 Regulatory Restrictions and Limitations

The following regulations and legislation are particularly relevant to the construction of ground heat exchangers:

BC Groundwater Protection Regulation

o Requires the use of registered water well drillers (for closed loop vertical borehole systems and groundwater open-loop systems) and registered pump installers for groundwater systems

o Specifies appropriate measures to protect groundwater aquifers

Common property rights must be respected including utility rights of way and other easements

BC Water Act and federal Fisheries Act

o Require approval for any activities in and about water bodies and the disturbance of fish habitat

More information on these regulations and legislation can be found at the BC Ministry of Environment, Water Protection & Sustainability Branch and Fisheries and Oceans Canada. 5.3 Guidelines

The following guidelines apply to geoexchange systems:

C448.1-02 Design and Installation of Earth Energy Systems for Commercial and Institutional Buildings; Canadian Standards Association, 2002.

Professional Guidelines for Geoexchange Systems in British Columbia - Part 1 Assessing Site Suitability and Ground Coupling Options; Geoexchange BC, 2007.

Professional Guidelines for Geoexchange Systems in British Columbia - Part 2 Design; Geoexchange BC, 2007.

Professional Guidelines for Geoexchange Systems in British Columbia - Part 4 Procurement Resource Guide; Geoexchange BC, 2011.

http://www.env.gov.bc.ca/wsd/plan_protect_sustain/groundwater/index.html

http://www.env.gov.bc.ca/wsd/plan_protect_sustain/groundwater/index.html

http://www.dfo-mpo.gc.ca/acts-loi-eng.htm



6.0 Other Barriers to Development Current barriers to the rapid expansion of geoexchange technology in BC include:

Limited number of skilled professionals and installers – however geoexchange installations do not require uncommon skills, but often require several different trades and professionals to work together that do not normally interact in any other situation (for example HVAC engineers and water well drillers). With an experienced coordinating professional, commercial installations can often be completed with local trades and contractors.

“One size fits all” approaches to design and construction in highly variable settings can lead to more expense than necessary and/or systems that that do not perform to expectations.



7.0 Participating Site and Theoretical Scenario Summaries The results of each of the site studies, proposed geoexchange options, and economic feasibility are summarized below.5 Economically viable geoexchange development opportunities were identified for three of the five facilities. Detailed feasibility study reports for each site are included in Appendix A. 7.1 Site A – Artificially Lit Greenhouse with CO2 Enrichment

7.1.1 Site Feasibility Site A is a 2,973 m2 (32,000 ft2) hot house used to grow organic long English cucumbers in the South Okanagan. The site is not currently serviced with natural gas and the nearest gas line is approximately 2 km away. Heat is currently provided by tanked propane and three 117 kW (400 MBH) propane forced-air unit heaters. The owner plans to extend the greenhouse operations to year round growing and is currently evaluating the options to upgrade the climate control systems to meet the requirements for 12 month use. Key upgrade plans include adding:

• artificial lighting (20 hours/day in winter),

• boiler and hydronic tube rail heat distribution system, and

• CO2 enrichment system. The analysis was based on the proposed twelve month operation. The energy modelling results from this site highlight several key heating characteristics of greenhouses employing artificial lighting and CO2 enrichment to maximize annual crop production:

Artificial lighting generates a vast amount of heat that reduces the annual heating required from the heating system by approximately 50%.

CO2 generation through fossil fuel combustion produces enough byproduct heat to provide approximately 70% of the remaining heat required from the heating system.

The remaining heating that can be targeted with a geoexchange system is therefore only approximately 15% of the heating that would be required in an equivalent greenhouse without lighting or CO2 enrichment.

A large field adjacent to the greenhouse was available to install a horizontal GHX and a small geoexchange system was proposed to handle base heating loads not covered by heat from CO2 enrichment. The proposed geoexchange system would provide 70% of the annual non-CO2 heating load, and is economically viable compared to the propane base case. However, a lower cost natural gas base case would make the proposed geoexchange system economically unattractive. The heat produced as a byproduct of CO2 enrichment significantly limits the opportunity for a geoexchange system to generate a return on investment. The proposed geoexchange capacity is theoretically capable of providing approximately 80% of the annual heating system requirements,

5 In Tables 2 – 5 IRR was calculated to determine the inherent value of the project itself – i.e. the return an owner would see if

they funded the entire project themselves. Because of this, the IRR in Tables 2 – 5 are therefore higher than the discount rate of 10% used for the CPI calculations because it does not include any financing costs.



however heat from CO2 enrichment drastically reduces the number of hours the geoexchange system operates and limits the geoexchange contribution to only 21%. 7.1.2 Theoretical Scenario Feasibilities The results from Site A were used to evaluate project feasibility under a range of utility structures, climate locations, base-case fuel sources, GHX construction options, and with and without CO2 enrichment constraints. Table 2 summarizes the profitability of each scenario and, for those that are not profitable, the conditions that would lead to profitability. Table 2. Geoexchange feasibility of Site A – lit greenhouse scenarios Details of utility rates and economic evaluation for each scenario are provided in Appendices B and C

For scenarios with CO2 enrichment, the base fuel strongly influences profitability – nearly all propane scenarios meet the target CPI while all of the natural gas scenarios are unprofitable. The two propane scenarios that require financial assistance involve an expensive vertically-bored GHX in poor ground conditions. These scenarios would meet the target CPI if propane costs are ≥ $0.70/L (PG scenario) and $0.83/L (SI scenario). A very small RHI of $0.91/MWhth would also cause the SI scenario to meet the CPI target. These scenarios are close enough to the target CPI that changing the assumed discount rate from 10% to 5% to evaluate the capital grant requirements was sufficient to cause a CPI greater than the target without any capital funding (noted by ** in Table 2).

Elect. Base GHX Elect. Nat. Gas Propane RHI Capital

Utility Fuel Type (%) $/kWh $/GJ $/L $/MWhth Grant

Lit Greenhouse With CO2 Enrich.

PG BCH Propane GW 86,900$ 35.8 19.3 1.01 - - - - -

PG BCH Propane V-Good 92,400$ 34.7 18.0 0.89 - - - - -

* SI FBC Propane H 66,000$ 29.0 17.8 0.86 - - - - -

SI BCH Propane GW 82,500$ 29.2 17.3 0.82 - - - - -

SI FBC Propane GW 82,500$ 29.9 16.0 0.71 - - - - -

SI BCH Propane V-Good 88,000$ 28.2 15.4 0.66 - - - - -

PG BCH Propane V-Poor 213,400$ 34.7 9.5 0.16 0.020$ - 0.70$ 23.39$ **

SI BCH Propane V-Poor 209,000$ 28.2 8.1 0.05 0.032-$ - 0.83$ 0.91$ **

PG BCH Nat Gas H 70,400$ 28.4 5.0 -0.13 0.018$ 13.66$ - 24.36$ 18,869$

PG BCH Nat Gas GW 86,900$ 29.3 4.6 -0.17 0.003$ 15.00$ - 32.22$ 27,361$

SI BCH Nat Gas GW 82,500$ 23.9 4.3 -0.20 0.017-$ 16.23$ - 39.35$ 29,011$

SI BCH Nat Gas H 66,000$ 23.1 3.5 -0.23 0.003$ 15.34$ - 34.51$ 28,457$

SI FBC Nat Gas GW 82,500$ 24.6 2.4 -0.31 0.017-$ 17.85$ - 48.51$ 45,665$

SI FBC Nat Gas H 66,000$ 23.8 0.2 -0.39 0.001$ 17.04$ - 45.42$ 47,677$

Lit Greenhouse Without CO2 Enrich.

SI BCH Propane GW 82,500$ 112.1 55.8 4.76 - - - - -

SI BCH Propane H 81,400$ 109.8 54.6 4.64 - - - - -

SI FBC Propane GW 82,500$ 115.1 51.2 4.06 - - - - -

SI FBC Propane V-Good 118,800$ 112.9 36.1 2.49 - - - - -

SI BCH Nat Gas GW 82,500$ 91.7 19.3 1.01 - - - - -

SI BCH Nat Gas H 81,400$ 89.8 18.3 0.94 - - - - -

SI FBC Propane V-Poor 324,500$ 112.9 16.0 0.54 - - - - -

SI FBC Nat Gas GW 82,500$ 94.7 13.8 0.52 - - - - -

SI FBC Nat Gas H 81,400$ 92.9 12.2 0.39 - - - - -

* Values for actual facility

** Projects cross the profitiability threshold when a 5% discount rate is used. CPI > 0.3 Meets or exceeds target CPI

No capital grant is required at this discount rate. 0.3 > CPI > 0 Profitable but not at target CPI

CPI < 0 Not currently profitable

PG = Prince George Region SI = Southern Interior Region

BCH = BC Hydro FBC = FortisBC

GW = Groundwater H = Horizontal V-Good = Vertical in good ground conditions V-Poor = Vertical in poor ground conditions

CPI Under

Existing

Conditions

Conditions Required for Profitiability

Cost to achieve a CPI of 0.3 if all else is unchanged.

File

Climate

Internal

Rate of

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Scenario Description Incremental

Capital Cost

Annual GHG

Savings

(tonnes

CO2e)



The electricity prices required for unprofitable scenarios to meet the target CPI with current fossil fuel prices are very low and unlikely to occur. In some cases the electricity price required is negative, indicating that the operator would need to be paid for their electrical consumption for the scenario to meet the target CPI threshold. This highlights the strong overriding effect of fossil fuel pricing on energy cost savings. All scenarios considered without CO2 enrichment are profitable at current energy costs without any RHI or capital grant assistance. 7.2 Site B – Seasonal Greenhouse without Artificial Lighting or CO2 Enrichment

7.2.1 Site Feasibility Site B is a 6,230 m2 (67,000 ft2) hot house used to grow peppers, tomatoes, and cucumbers on the Sunshine Coast of BC. The facility consists of two distinct but adjoining greenhouse structures, including a glass structure and a soft-wall poly structure. The site is not currently serviced by natural gas and the nearest gas line is approximately 15 km away. Heating is currently provided by an electric boiler on a low electric-plus electric rate and is supplemented by propane and waste oil boilers. Two large fields adjacent to the greenhouse are potentially available to install a horizontal GHX and two geoexchange system sizes (112 nominal tons and 56 nominal tons) were proposed based on the area available and the heating load profile. The larger geoexchange system would provide 55% of the annual heating load, however due to the very low electric utility rate at the facility, this scenario did not meet the target profitability threshold. The smaller geoexchange system would provide 43% of the annual heating load and is economically viable compared to the propane base case. 7.2.2 Theoretical Scenario Feasibilities The results from Site B were used to evaluate project feasibility under a range of utility structures, climate locations, base-case fuel sources, and GHX construction options. All scenarios with propane as the base fuel are profitable. The proposed 56 nominal ton system is economically viable under current conditions and the larger 112 nominal ton system would also meet the target CPI at electrical rates greater than or equal to $0.033/kWh. Application of geoexchange at this site offers relatively limited GHG reductions because the geoexchange operation is displacing electric boiler operation and the displaced BC Hydro electricity has a relatively low GHG emission factor.

Table 3 summarizes the profitability of each scenario and, for those that are not profitable, the conditions that would lead to profitability. All scenarios with propane as the base fuel are profitable. The proposed 56 nominal ton system is economically viable under current conditions and the larger 112 nominal ton system would also meet the target CPI at electrical rates greater than or equal to $0.033/kWh. Application of geoexchange at this site offers relatively limited GHG reductions because the geoexchange operation is displacing electric boiler operation and the displaced BC Hydro electricity has a relatively low GHG emission factor.



Table 3. Geoexchange feasibility of Site B – greenhouse scenarios Details of utility rates and economic evaluation for each scenario are provided in Appendices B and C

7.3 Site C – Poultry Broiler Farm

7.3.1 Site Feasibility Site C is a 75,000 bird broiler barn operation with plans to expand to 100,000. The two-level 4,740 m2 (51,000 ft2) facility is located in the Fraser Valley. The operation is year-round and conforms to an 8-week growing cycle with 6.5 cycles per year. Each cycle consists of 6 growing weeks with two weeks for cleaning and preparation at the end of each cycle. Temperature control is critical to maintain growing conditions and to reduce mortality. Warmer temperatures are required at the beginning of the cycle (starting at 35 °C) and then the temperature is progressively ramped down as the cycle progresses. The facility is currently served by natural gas and is currently heated with a simple natural gas radiant brooder heater system. It is technically feasible to adapt geoexchange heating for the Site C Poultry Barn, and of the various options available for ground heat exchange, a horizontal trenched approach is most suitable. However, while geoexchange is technically feasible and capable of significantly reducing natural gas consumption and GHG emissions, the study concludes that the application of geoexchange in this application and site setting does not meet the profitability criteria established for the study. There are two main reasons this application fails to meet profitability:



LM BCH Propane GW 369,600$ 345.9 52.9 4.41 - - - - -

PG BCH Propane GW 739,200$ 597.8 43.2 3.39 - - - - -

SI BCH Propane GW 554,400$ 427.9 42.1 3.27 - - - - -

SI FBC Propane GW 554,400$ 436.1 40.1 3.06 - - - - -

PG BCH Propane H 862,400$ 578.5 37.5 2.81 - - - - -

LM BCH Propane V-Good 554,400$ 327.7 36.5 2.72 - - - - -

SI BCH Propane H 646,800$ 405.4 36.0 2.65 - - - - -

SI FBC Propane H 646,800$ 413.7 34.2 2.47 - - - - -

LM BCH Propane V-Poor 1,232,000$ 327.7 19.0 1.01 - - - - -

LM BCH Nat. Gas GW 369,600$ 283.8 14.4 0.55 - - - - -

* LM BCH Electric H (56T) 238,000$ 17.6 13.4 0.47 - - - - -

LM BCH Nat. Gas H 431,200$ 268.8 11.7 0.34 - - - - -

SI BCH Nat. Gas GW 554,400$ 351.0 11.7 0.33 - - - - -

PG BCH Nat. Gas GW 739,200$ 489.7 11.3 0.30 - - - - -

* LM BCH Electric H (112T) 431,200$ 23.3 9.8 0.19 0.033$ - - 5.18$ **

PG BCH Nat. Gas H 862,400$ 473.9 9.7 0.18 0.050$ 10.19$ - 5.73$ **

SI BCH Nat. Gas H 646,800$ 332.4 9.5 0.17 0.049$ 10.37$ - 7.04$ **

SI FBC Nat. Gas GW 554,400$ 359.1 8.8 0.12 0.071$ 10.49$ - 7.78$ **

SI FBC Nat. Gas V-Good 831,600$ 340.6 5.7 -0.10 0.025$ 13.43$ - 27.78$ 156,642$

SI FBC Nat. Gas V-Poor 1,848,000$ 340.6 3.9 -0.26 0.111-$ 22.06$ - 86.26$ 751,986$

* Values for actual facility with 56 or 112 nominal ton geoexchange systems.




LM = Lower Mainland PG = Prince George Region SI = Southern Interior Region





Climate

File

Internal

Rate of

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Capital Cost

Annual GHG

Savings

(tonnes

CO2e)

CPI Under

Existing

Conditions



The geoexchange system cannot be adapted to use an existing heat distribution system within the barns. Therefore a completely new and separate heat distribution needs to be added within the barns.

The prevailing very low cost of natural gas constrains profitability prospects for this application.

This same application compared to a theoretical propane base case is profitable. 7.3.2 Theoretical Scenario Feasibilities The results from Site C were used to evaluate project feasibility under a range of utility structures, climate locations, base-case fuel sources, and GHX construction options. Table 4 summarizes the profitability of each scenario and, for those that are not profitable, the conditions that would lead to profitability. Table 4. Geoexchange feasibility of Site C – poultry barn scenarios Details of utility rates and economic evaluation for each scenario are provided in Appendices B and C

Although a geoexchange system is not recommended for the actual facility, the same application is profitable for all scenarios with propane as the base fuel, except the high cost vertical GHX in poor ground conditions. This highlights the strong effect of fossil fuel costs on project economics. 7.4 Site D – Poultry Processing Facility

7.4.1 Site Feasibility Site D is a 706 m2 (7,600 ft2) poultry processing facility on Vancouver Island. The site is serviced by natural gas. Heat is currently provided by electric baseboards, a gas-fired make-up air unit for ventilation, and two gas-fired process hot water tanks. Cooling is currently provided by separate



PG BCH Propane GW 415,800$ 146.7 16.8 0.75 - - - - -

PG BCH Propane H 462,000$ 146.4 15.3 0.63 - - - - -

SI BCH Propane GW 284,900$ 87.7 14.9 0.59 - - - - -

SI FBC Propane GW 284,900$ 90.1 14.9 0.59 - - - - -

LM BCH Propane GW 284,900$ 87.2 14.9 0.59 - - - - -

SI BCH Propane H 308,000$ 87.5 13.8 0.50 - - - - -

SI FBC Propane H 308,000$ 90.1 13.6 0.48 - - - - -

LM BCH Propane V-Good 369,600$ 86.9 11.7 0.34 - - - - -

LM BCH Propane V-Poor 708,400$ 86.9 7.2 -0.01 0.079$ - 0.91$ 66.00$ **

LM BCH Nat. Gas GW 284,900$ 71.4 2.3 -0.24 0.035-$ 18.19$ - 46.63$ 141,831$

PG BCH Nat. Gas GW 415,800$ 120.0 2.5 -0.24 0.018-$ 17.25$ - 40.43$ 210,961$

SI BCH Nat. Gas GW 284,900$ 71.8 2.2 -0.25 0.034-$ 18.83$ - 47.39$ 148,125$

SI FBC Nat. Gas GW 284,900$ 74.2 2.1 -0.26 0.033-$ 18.92$ - 47.84$ 150,779$

* LM BCH Nat. Gas H 308,000$ 71.1 1.9 -0.28 0.042-$ 20.30$ - 54.09$ 170,707$

SI BCH Nat. Gas H 308,000$ 71.6 1.9 -0.28 0.042-$ 20.04$ - 53.82$ 171,306$

PG BCH Nat. Gas V-Good 554,400$ 119.7 2.3 -0.29 0.052-$ 20.60$ - 58.17$ 298,851$

SI FBC Nat. Gas H 308,000$ 74.1 1.5 -0.30 0.042-$ 20.35$ - 55.43$ 180,685$

PG BCH Nat. Gas V-Poor 1,062,600$ 119.7 2.6 -0.34 0.580-$ 21.10$ - 120.65$ 596,519$





LM = Lower Mainland PG = Prince George Region SI = Southern Interior Region





Climate

File

Internal

Rate of

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Capital Cost

Annual GHG

Savings

(tonnes

CO2e)

CPI Under

Existing

Conditions



refrigeration units serving the blast cooler, processing (cut and pack) room, storage freezer, two storage coolers and shipping cooler. The two major energy loads of the facility are service water heating (SWH) and rapid refrigeration of carcasses in a blast cooler immediately after processing. The other heating and cooling systems in the facility did not have large enough energy loads to warrant including them in the proposed geoexchange retrofit. It is technically feasible to recover heat directly from the blast cooler equipment and transfer that heat to a SWH pre-heating system and to provide further SWH pre-heating with a geoexchange system. Of the various options available for ground heat exchange, a horizontal trenched approach is most suitable. A new direct heat recovery and 6.5 nominal ton geoexchange system would significantly reduce energy costs at the facility and is economically viable compared to the natural gas base case. 7.4.2 Theoretical Scenario Feasibilities The results from Site D were used to evaluate project feasibility under a range of utility structures,

climate locations, base-case fuel sources, and GHX construction options. Table 5 summarizes the

profitability of each scenario and, for those that are not profitable, the conditions that would lead to

profitability.



Table 5. Geoexchange feasibility of Site D – poultry processing scenarios Details of utility rates and economic evaluation for each scenario are provided in Appendices B and C

All scenarios based on Site D are profitable. Only the high-cost vertical GHX in poor ground conditions was significantly below the target CPI. The climate profile for these scenarios does not significantly influence the profitability results because all of the heating covered by the geoexchange system is process heating that is not strongly influenced by outdoor air temperatures. Therefore these results are also representative of expected outcomes for similar facilities in other climatic regions. 7.5 Site E – Closed-Loop Aquaponic Facility

7.5.1 Site Feasibility Site E is an aquaponics operation near Prince George, BC. The existing operation is housed in a 270 m2 (2,900 ft2) poly-covered greenhouse. Aquaponics is a food-producing method that combines aquaculture with hydroponics. In this situation, the aquaculture part of the system consists of six 8,000 L tanks used to raise tilapia fish, while the hydroponic part of the system consists of 12 growing beds that produce herbs and vegetables. The facility is currently heated by a rooftop solar thermal system in combination with wood biomass boilers. The study examined the technical feasibility and economic viability for developing two distinctly different types of geoexchange energy system improvements for the facility, including:

Developing a typical geoexchange system for facility heating that would operate in combination with the existing solar and wood biomass boilers

Developing a below-ground thermal energy store for capturing excess summer solar heat produced by the rooftop solar thermal system and shifting some of the excess supply so that it can be used for gainful benefit in autumn and winter seasons

The latter of these options was examined at the specific request of the Site Owner. It is technically feasible to adapt a typical geoexchange system for the Site E. Of the various options available for ground heat exchange, a horizontal trenched approach is most suitable. However, while technically feasible, the development of a typical geoexchange system for this application in this site



SI FBC Propane GW 41,455$ 45.5 44.2 3.98 - - - - -

VI BCH Propane H 43,860$ 45.5 44.2 3.95 - - - - -

VI BCH Propane GW 71,375$ 46.5 30.9 2.34 - - - - -

SI FBC Propane GW 71,375$ 46.5 29.6 2.20 - - - - -

* VI BCH Nat. Gas H 43,860$ 37.4 26.7 1.68 - - - - -

SI FBC Nat. Gas V-Good 50,100$ 37.4 14.9 0.71 - - - - -

VI BCH Nat. Gas GW 71,375$ 38.2 13.2 0.54 - - - - -

SI FBC Nat. Gas GW 76,500$ 45.5 11.1 0.29 0.100$ 9.62 - 1.61 **

SI FBC Nat. Gas V-Poor 86,500$ 38.2 10.1 0.21 0.070$ 10.44 - 19.08 **





SI = Southern Interior Region VI = Vancouver Island





Climate

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Internal

Rate of

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Capital Cost

Annual GHG

Savings

(tonnes

CO2e)

CPI Under

Existing

Conditions



setting does not meet the profitability criteria established for the study. Nor would GHG emission reductions occur. The principal reason is the wood biomass base-case scenario provides low cost heat with neutral GHG emissions. It is also technically feasible to develop a below-ground thermal store to capture and preserve some of the solar heat that is currently wasted. However, there are technical constraints that mean the amount of heat that can be gainfully preserved is relatively small. Consequently, the development of a below-ground thermal store does not meet the profitability criteria established for the study, nor would GHG emission reductions occur. 7.5.2 Theoretical Scenario Feasibilities We did not consider additional theoretical scenarios for Site E because of the very uncommon circumstances at this site. The very unique combination of operations, large solar thermal collector, and pre-existing vertical ground heat exchanger are unlikely to occur in other settings and therefore theoretical scenarios based on this facility would provide little additional information of value to the project.



8.0 Benchmarking Using the site assessments and theoretical scenarios, we have evaluated a wide range of potential geothermal systems with proposed system capacities from 5 to 224 tons, and project costs from $46,500 to $1.85 million. Of the 70 scenarios evaluated and presented in Tables 2 through 5, 63% are considered profitable, 11% are profitable but do not meet the target threshold, and 26% are not profitable under current conditions. By evaluating a broad range of conditions, several clear patterns emerge that can be used to characterize the circumstances that most commonly lead to profitable geoexchange systems. These relate to annual heating and cooling requirements, energy costs, available GHX options, and interior distribution systems as described below. In this section we also summarize the RHI and capital cost assistance that would be required to make otherwise unprofitable scenarios economically attractive to agricultural and agri-food operation owners. 8.1 Characteristics of Profitable Geoexchange Systems

8.1.1 Annual Heating and Cooling Requirements A common feature of the profitable scenarios is a long duration heating load (all scenarios were predominantly heating dominated, however the same outcome would apply to cooling loads). This occurs because capital equipment can only generate a return on investment when operating. Short duration, high intensity loads are the least profitable because the cost to install geoexchange systems increases directly with capacity. If very expensive, high capacity equipment and GHX only operate for a limited number of hours a year, they cannot produce enough savings to overcome the high installation costs. In all scenarios the capacity of the proposed geoexchange options were selected in an effort to optimize the operating time of the systems. However, different operations inherently have different heating load durations. Those with longer duration heating requirements including relatively continuous process heating requirements and/or summer heating loads are the most likely to be profitable. For example, the heating hours for the proposed geoexchange system at Site A (lit greenhouse with CO2 enrichment) are limited by the CO2 enrichment requirements. Despite optimizing the geoexchange capacity to the available load, this set of scenarios includes the lowest profitability score measured in the study and this option is only profitable with less expensive GHX options when compared to a propane base case. Six of the 18 unprofitable scenarios in the study are from Site A due to the limitations imposed by CO2 enrichment. However, in the Site A scenarios without CO2 enrichment heat (either through bottled CO2 or a similar facility that does not use supplemental CO2), the same system has a much longer run time and becomes profitable under all GHX and base fuel scenarios. The long duration heating, including crop heating in much of the summer, allows the same geoexchange capacity to produce the highest profitability score of all scenarios despite requiring a larger GHX to accommodate greater heat extraction. Because GSHPs can provide both heating and cooling, long run times can also occur for facilities that require both winter heating and summer cooling. Facilities that have concurrent heating and cooling loads such as Site D (poultry processing facility) can often recover the heat being rejected in the cooling process and use it to offset heating requirements. Depending on the specific circumstances, heat can be



recovered passively or actively with a GSHP. Heat recovery from concurrent cooling loads is often very profitable. 8.1.2 Energy Costs Geoexchange systems usually involve switching a large portion of annual energy costs away from fossil fuel combustion to electricity that drives the heat pump process. Therefore the relative costs of fossil fuels and electricity have a strong effect on the profitability of these projects. The effects of propane, natural gas, and electricity costs are described below; however the same principles can be applied to the relative cost of other base-case fuels such as biomass, heating oil, or coal. Propane Almost all 35 scenarios with propane as the base-case fuel were profitable. Two scenarios

were profitable but did not meet the selected profitability threshold, and only one is considered unprofitable. All three are scenarios with more expensive vertical drilled GHX scenarios assuming poor conditions for a V-GHX. The propane prices that would make these three scenarios pass the profitability threshold are $0.70/L, $0.83/L, and $0.91/L. Therefore these scenarios may pass the threshold in regions of the province with higher propane rates.

Natural gas 17 of the 33 natural gas scenarios are not profitable at current low natural gas prices, and five scenarios are profitable but below the threshold. However, even with natural gas at the lowest prices in a decade, there are still 11 scenarios in which geoexchange can make economic sense. These are commonly the very long duration heating scenarios described in section 8.1.1 Load Duration in combination with low cost H-GHX or GW-GHX ground couplings. The range of blended natural gas prices required for profitability in the 23 scenarios below the profitability threshold is $9.62/GJ to $22.06. Seven scenarios require prices below $13.70/GJ and would pass the profitability threshold at natural gas prices experienced in the recent past.

Electricity Although lower electrical rates do improve the economics for geoexchange systems versus fossil fuel base-case scenarios, changes in electrical rates have a limited effect on profitability due to the overriding effect of fossil fuel prices on energy cost savings. FortisBC and BC Hydro rates were both equally likely to lead to profitability. Lower rates improved the economics but do not cause otherwise similar scenarios to cross the profitability threshold. In many scenarios profitability cannot be achieved with changes in electrical rates alone. When electric resistance heating is the base case, higher electrical rates increase the profitability of geoexchange systems. In the two scenarios with an electric resistance base case (Site B greenhouse) one geoexchange scenario was profitable at the existing rate of $0.029/kWh while the other became profitable at $0.033/kWh.

8.1.3 Available GHX Options GHX costs estimates ranged by an order of magnitude for some scenarios, highlighting the key role site-specific characteristic can play in project economics. The most profitable scenarios occur where GW-



GHX and H-GHX options are available. However, several V-GHX scenarios were also profitable as described below. GW-GHX In certain rare settings with highly productive aquifers, very high GHX capacity can be

achieved at a relatively low cost. Where these conditions exist, geoexchange systems can be profitable over a broad range of load durations and base-case fuel options. Twenty two of 31 GW-GHX scenarios are profitable. However, it is important to note that this represents the profitability where rare conditions exist, not the likelihood that a suitable GW-GHX option will be available. In some circumstances an owner may already have a high capacity well in place that could be used to supply a geoexchange system. These conditions can be very profitable because a significant portion of the GHX cost is eliminated. In situations where new wells must be drilled for a GW-GHX, the fixed costs associated with drilling, well production and testing, pump installation, etc. often makes the GW-GHX option less attractive than closed-loop GHX options for very small geoexchange systems (often not suitable for less than 10 to 20 nominal tons).

H-GHX Agricultural and agri-food operations often have the larger land area required for horizontal ground coupling options. Fourteen of 23 H-GHX options are profitable. Only the scenarios with short duration loads (Site A – Lit greenhouse with CO2 enrichment) and higher cost interior distribution (Site C – Poultry broiler farm) compared to a natural gas base case were unprofitable. The ground conditions in the upper 4 ft to 8 ft can influence construction costs for H-GHX options. Very inexpensive H-GHXs can often be installed with little surface disturbance in softer soils with little or no large granular materials using a chain trencher. Trenching with an excavator is more common with installation costs varying depending on trench wall stability and presence of larger boulders that affect the excavator time required. In some settings with unconsolidated free-flowing materials, the most cost effective installation approach is to strip a larger single excavation with a dozer rather than multiple trenches.

V-GHX For some facilities, a V-GHX may be the only ground coupling option available. In these cases it is important to evaluate ground conditions carefully. In BC’s diverse geological settings, the costs associated with installing a V-GHX can vary significantly and be the determining factor in a project’s profitability. Installed cost is dependent on both the ease of drilling / HX pipe installation and on the ground thermal properties that influence the total length of GHX required. Good conditions occur where straightforward drilling techniques can be used and high thermal conductivity allows shorter total borehole length. Shallow bedrock often provides good conditions. Poor conditions occur where multiple drilling techniques are required (e.g. bedrock overlain by 12 m to 24 m of unconsolidated materials) or where drilling is otherwise challenging or expensive (e.g. highly fractured bedrock, the presence of large boulders in unconsolidated materials, etc.). Low thermal conductivity of materials like dry gravels or clays can require considerably longer total bore length, however in many settings this can be offset by less costly drilling options.



V-GHX options were not proposed in any of the site feasibility studies where less costly H-GHX options were available. V-GHX feasibility was assessed for 8 theoretical scenarios. When good drilling conditions are assumed 6 of 8 scenarios are profitable, however if poor conditions are assumed only 2 of 8 remain profitable.

8.1.4 Interior Distribution Systems In several of the site assessments, geoexchange systems were proposed that could integrate directly with existing heating distributions systems. In some cases the existing distribution system limited the capacity of GSHP that could be used without additional distribution system modifications. In other cases, expensive additions to the distribution system were required to make geoexchange possible. The extra expense to modify existing distribution systems or to install new ones lowers the overall profitability of these scenarios. Additional distribution costs are often required for existing heating and cooling systems based on many small distributed unit heaters or roof top units rather than a central boiler or furnace. For example, Site C (Poultry broiler farm) currently delivers heat through standalone natural gas radiant heaters. To retrofit this facility with a geoexchange system would require installing an entirely new distribution system. These extra costs made this facility less profitable than other facilities across all scenarios. New construction often provides more flexibility than retrofit situations for designing a distribution system with geoexchange in mind. In retrofit scenarios, geoexchange systems are often most easily adapted to existing hot water heating distribution systems. 8.2 Incentives for Currently Unprofitable Scenarios

One of the main goals of this study is to determine the financial incentives that are required to make geoexchange technology economically viable for agricultural and agri-food operations in BC. Of the 70 scenarios evaluated, only 37% did not meet the study target profitability under existing current conditions. Two incentive options were considered for these scenarios, renewable heat incentives and capital cost sharing. 8.2.1 Renewable Heat Incentives Renewable heat incentives are used to pay operators to generate heat from renewable sources at a set price per unit of renewable heat delivered ($/MWhth)6. This type of incentive program is similar to the feed-in tariffs often applied to promote the development of renewable electrical generation. For the 8 scenarios that are profitable but do not meet the target profitability, the range of renewable heat incentives required to pass the threshold is $0.91/MWhth to $23.39/MWhth. For the 18 scenarios that are currently unprofitable, the range of renewable heat incentives required to pass the threshold is $24.36/MWhth to 120.65/MWhth (Mode = $47.39/MWhth). Renewable heat incentives for all 26 scenarios below the target profitability are shown in Table 6. 8.2.2 Capital Cost Sharing Capital cost sharing incentives are currently available to eligible farms through the Canada-British Columbia Environmental Farm Plan Program for farm practices specified within the Beneficial

6 $1.00/MWhth is equal to $0.29/MMbtu or $0.28/GJ



Management Practices Program. Currently 30% of eligible costs to a maximum of $50,000 is available for replacement of fossil-fuel dependent space heating with renewable heating including: geothermal infrastructure, heat pumps, heat exchangers and heat conveyance infrastructure, warm water tanks, and assessment design and construction costs. See full eligibility criteria at www.bcefp.ca. Nine additional scenarios pass the target profitability when the available capital cost sharing incentive is applied (Table 6). The current incentive value of 30% of eligible costs to a maximum of $50,000 appears sufficient to make scenarios that are profitable but did not meet the target threshold become economically attractive without incenting investment in clearly unprofitable scenarios. Table 6. Financial incentives required to meet a Chabot Profitability Index of 0.3 Either RHI or capital cost sharing are required but not both

Site Climate GHX RHI

Type $/MWhth

A PG BCH Propane V-Poor 0.16 23.39$ ** ** 1.06

A SI BCH Propane V-Poor 0.05 0.91$ ** ** 0.81

A PG BCH Nat. Gas H -0.13 24.36$ 18,869$ 26.8% 0.35

A PG BCH Nat. Gas GW -0.17 32.22$ 27,361$ 31.5% -0.02

A SI BCH Nat. Gas GW -0.20 39.35$ 29,011$ 35.2% -0.06

A SI BCH Nat. Gas H -0.23 34.51$ 28,457$ 43.1% -0.14

A SI FBC Nat. Gas GW -0.31 48.51$ 45,665$ 55.4% -0.26

A SI FBC Nat. Gas H -0.39 45.42$ 47,677$ 72.2% -0.31

B LM BCH Electric H 0.19 5.18$ ** ** N.A.

B PG BCH Nat. Gas H 0.18 5.73$ ** ** 0.66

B SI BCH Nat. Gas H 0.17 7.04$ ** ** 0.66

B SI FBC Nat. Gas GW 0.12 7.78$ ** ** 0.56

B SI FBC Nat. Gas V-Good -0.10 27.78$ 156,642$ 18.8% 0.11

B SI FBC Nat. Gas V-Poor -0.26 86.26$ 751,986$ 40.7% -0.11

C LM BCH Propane V-Poor -0.01 66.00$ ** ** 0.39

C LM BCH Nat. Gas GW -0.24 46.63$ 141,831$ 49.8% -0.10

C PG BCH Nat. Gas GW -0.24 40.43$ 210,961$ 50.7% -0.15

C SI BCH Nat. Gas GW -0.25 47.39$ 148,125$ 52.0% -0.12

C SI FBC Nat. Gas GW -0.26 47.84$ 150,779$ 52.9% -0.24

C LM BCH Nat. Gas H -0.28 54.09$ 170,707$ 55.4% -0.17

C SI BCH Nat. Gas H -0.28 53.82$ 171,306$ 55.6% -0.18

C PG BCH Nat. Gas V-Good -0.29 58.17$ 298,851$ 53.9% -0.20

C SI FBC Nat. Gas H -0.30 55.43$ 180,685$ 58.7% -0.29

C PG BCH Nat. Gas V-Poor -0.34 120.65$ 596,519$ 56.1% -0.25

D SI FBC Nat. Gas GW 0.29 1.61$ ** ** 2.16

D SI FBC Nat. Gas V-Poor 0.21 19.08$ ** ** 1.85

* CPI Calculated with 5% discount rate

**

LM = Lower Mainland PG = Prince George Region SI = Southern Interior Region CPI > 0.3

BCH = BC Hydro FBC = FortisBC 0.3 > CPI > 0

GW = Groundwater H = Horizontal V-Good = Vertical in good ground conditions CPI < 0

V-Poor = Vertical in poor ground conditions

Capital Cost

Sharing Required

(%)

CPI* With 30%

Cost Sharing up

to $50,000

Projects cross the profitiability threshold when a 5% discount rate is used for capital grant calculations. Capital grant is no longer required at this

discount rate.

Electric

Utility

Base Case

Fuel

CPI Under

Existing

Conditions

Capital Cost

Sharing Required

for CPI = 0.3*

http://www.bcefp.ca/



9.0 Self Assessment Guide 9.1 Estimating Potential Savings

A quick estimate of the potential energy costs savings that could be achieved with a geoexchange system can be calculated with the formulas below. These calculations are based on a number of simplifying assumptions, but will provide a rough estimate for owners to determine if the potential savings from a geoexchange system warrant further evaluation. Readers should note that operations with simultaneous heating and cooling needs may achieve significantly higher energy cost savings than estimated by the formulas below. Optimal sizing of a geoexchange system may also lead to a higher or lower proportion of the annual load being provided by the heat pump than has been assumed in these calculations.

Potential geoexchange savings vs. electric resistance heating Hybrid system with geoexchange serving 70% of annual load and electric resistance serving 30%

Current annual cost of electric heating: $_____________(A) 1) Multiply

annual electric heating cost (A)

by 0.52 to estimate

annual cost with hybrid geoexchange: $_____________(B)

2) Subtract B from A to estimate the potential savings from geoexchange: $_____________

(Assumes a GSHP average COP of 3.2)



Potential geoexchange savings vs. propane Hybrid system with geoexchange serving 70% of annual load and propane serving 30%

Current annual cost of propane: $_____________(A) 1) Multiply

annual propane use: _________Litres (total from utility bills)

by 1.2 to estimate

annual GSHP energy consumption: _________kWh (B)

2) Multiply (B) by your current electrical rate in $/kWh to estimate

annual cost of electricity: $_________ (C)

3) Multiply (A) by 0.3 to estimate

reduced annual cost of propane: $_________ (D)

4) Add C and D to estimate the annual cost with hybrid geoexchange: $_____________(E)

5) Subtract E from A to estimate the potential savings from geoexchange: $_____________

(Assumes propane seasonal heating efficiency of 80%, GSHP average COP of 3.2)

Potential geoexchange savings vs. natural gas Hybrid system with geoexchange serving 70% of annual load and natural gas serving 30%

Current annual cost of natural gas: $_____________(A) 1) Multiply

annual gas consumption: _________GJ (total from utility bills)

by 48.7 to estimate

annual GSHP energy consumption: _________kWh (B)

2) Multiply (B) by your current electrical rate in $/kWh to estimate

annual Cost of Electricity: $_________ (C)

3) Multiply (A) by 0.3 to estimate

reduced annual cost of gas: $_________ (D)

4) Add C and D to estimate the annual cost with hybrid geoexchange: $_____________(E)

5) Subtract E from A to estimate the potential savings from geoexchange: $_____________

(Assumes natural gas seasonal heating efficiency of 80%, GSHP average COP of 3.2)



9.2 Predicting Site Suitability

Given the many variables that influence the profitability of geoexchange systems, it can be challenging to determine the suitability of geoexchange for a particular application without a detailed site assessment. However, based on the common characteristics of profitable scenarios discussed in this study, owners can use the figures on the following page to judge the likelihood that a geoexchange system will be suitable at their operation. Some operations may have all the features of profitable systems listed under High Likelihood of Suitability. These operations are highly likely to benefit from a geoexchange system and owners are encouraged to take further steps to evaluate the possibility of using geoexchange technology at their site. Similarly, some operations may have all the features of unprofitable systems listed under Low Likelihood of Suitability and likely do not warrant further consideration of geoexchange at this time without some additional information to suggest otherwise. The majority of agricultural operations will have a combination of characteristics from both lists. For these operations, owners should weigh the benefits of the potential energy cost savings calculated in Section 9.1 against the mix of features at their site. Operations with the potential for considerable savings and at least one of the features listed under High Likelihood of Suitability warrant a discussion with a professional to determine if a detailed evaluation is justified.



•Radiant floor heat

•Hot water radiators or fan coils

•New construction

•High capacity well

•Large open area

•Easy trenching

•Good drilling conditions

•Propane

•Heating oil

•Electricity

•Long heating season

•Process heating

•Summer heating

•Both heating and cooling

High Heating and Cooling

Needs

High Current Fuel Costs

Existing Distribution

System

Low Cost Ground

Conditions

•Distributed heaters or roof top units

•Electric baseboards

•Temps above 50 °C

•Limited space

•Large boulders

•Challenging drilling conditions

•Natural gas

•Local biomass

•Other low cost fuels

•Short heating season

•CO2 enrichment from combustion

•Infrequent or no process heating

Low Heating and Cooling

Needs

Low Current Fuel Cost

Existing Distribution

System

High Cost Ground

Conditions

High Likelihood of Suitability

Low Likelihood of Suitability



10.0 Geoexchange Technology Vendors Commercial geoexchange systems should be designed and coordinated by a registered professional engineer with appropriate experience as required in C448.1-02 Design and Installation of Earth Energy Systems for Commercial and Institutional Buildings; Canadian Standards Association, 2002. Engineers and service providers specializing in geoexchange technology can be found through the organizations listed below. GeoExchange BC service directory – www.geoexchangebc.com Canadian Geoexchange Coalition members and accredited installers, designers, drillers and companies listed by province – www.geo-exchange.ca BC Ministry of Environment Registered Water Well Drillers and Pump Installers – http://www.env.gov.bc.ca

http://www.geoexchangebc.com/membership_directory.php

http://www.geo-exchange.ca/

http://www.env.gov.bc.ca/wsd/plan_protect_sustain/groundwater/wells.html#reg



11.0 Conclusions The purpose of this study was to:

To provide a thorough understanding of the feasibility of geoexchange heating and cooling technology at each participating agricultural and agri-food operation,

To inform the BC Ministry of Agriculture and other stakeholders regarding the wider opportunity for geoexchange technology in the agriculture sector through the development of economic and feasibility benchmarks, and

To develop tools based on the findings of the benchmarking analyses that allow BC agricultural and agri-food operators to conduct preliminary self assessments to determine the likelihood that a geoexchange system could be viable for their heating and cooling needs.

Detailed feasibility reports were prepared for five participating operations and additional design and evaluation work was recommended for three of these where economically viable geoexchange options were identified. The feasibility of the proposed geoexchange systems for four sites was evaluated under a broad range of theoretical conditions to determine benchmark characteristics of profitable scenarios and evaluate possible incentive programs. The key attributes that influence profitability in these scenarios are the:

duration of heating or cooling loads,

cost of base-case energy source,

availability of low cost GHX options, and

adaptability of existing heat distribution systems The current cost sharing rates available for geoexchange systems through the Canada-British Columbia Environmental Farm Plan – Beneficial Management Practices Program appear to be well suited for encouraging investment in projects that may not be quite profitable enough on their own, without promoting investment in poor applications of geoexchange technology. Additional evaluation of geoexchange feasibility at other sites could be considered to broaden these results to other agriculture and agri-food sectors.

Appendix A – Detailed Geoexchange Feasibility Study Results

JDQ Engineering Limited A38

Site A – Artificially lit greenhouse with CO2 enrichment

Table of Contents 1.0 Executive Summary ......................................................................................................................... 39

2.0 Background ..................................................................................................................................... 39

3.0 Scope of Work ................................................................................................................................. 40

4.0 Existing Operation ........................................................................................................................... 40

4.1 General Description .................................................................................................................... 40

4.2 Current Heating and Cooling Systems ........................................................................................ 41

4.3 Proposed Expansions or Renovations ......................................................................................... 41

4.4 Base Case Energy Analysis .......................................................................................................... 41

4.5 Potential Energy Conservation Opportunities ............................................................................ 44

5.0 Site Characteristics .......................................................................................................................... 45

5.1 Subsurface Information .............................................................................................................. 46

6.0 Geoexchange Options ..................................................................................................................... 48

6.1 GHX Option Comparison ............................................................................................................. 49

6.2 Proposed Conceptual Design ...................................................................................................... 52

6.3 Geoexchange Option Energy Analysis......................................................................................... 53

6.4 Geoexchange Options Cost Estimate .......................................................................................... 53

7.0 Geoexchange Feasibility ................................................................................................................. 54

7.1 Technical Feasibility .................................................................................................................... 54

7.2 Financial Feasibility ..................................................................................................................... 54

7.3 Conditions Required for Feasibility ............................................................................................. 56

8.0 Conclusions ..................................................................................................................................... 57

9.0 Recommended Next Steps .............................................................................................................. 57

Standard Limitations This report is intended for use by the site owner and the BC Ministry of Agriculture for specific application to the subject site, and for specific application to the subject geoexchange evaluation project. Any use of this report by a third party or any reliance on decisions based on this report, are the responsibility of those third parties. JDQ Engineering Limited accepts no responsibility for damages, if any, suffered by any third party as a result of decisions made or actions taken based on this report.

The analysis and calculations presented in this report are provided for purposes of supporting preliminary evaluations. Note that the calculations presented herein are based on various estimates and assumptions, and further site-specific investigations and energy analyses may be required to refine the analyses prior to preparing a detailed design. Detailed designs that may arise from the findings of this report will need to be carried out by fully qualified practitioners.

In preparing this analysis we have relied in good faith on information provided or prepared by others, the accuracy of which we cannot attest to.

Appendix A Site A – Artificially lit greenhouse with CO2 enrichment


1.0 Executive Summary Site A is a 2,973 m2 (32,000 ft2) hot house used to grow organic long English cucumbers in the South Okanagan. The site is not currently serviced with natural gas and the nearest gas line is approximately 2 km away. Heat is currently provided by tanked propane and three 117 kW (400 MBH) propane forced-air unit heaters. The owner plans to extend the greenhouse operations to year round growing and is currently evaluating the options to upgrade the climate control systems to meet the requirements for 12 month use. Key upgrade plans include adding:

• artificial lighting (20 hours/day in winter),

• boiler and hydronic tube rail heat distribution system, and

• CO2 enrichment system. The analysis was based on the proposed twelve month operation. The energy modeling results from this site highlight several key heating characteristics of greenhouses employing artificial lighting and CO2 enrichment to maximize annual crop production:




A large field adjacent to the greenhouse was available to install a horizontal GHX and a small geoexchange system was proposed to handle base heating loads not covered by heat from CO2 enrichment. The proposed geoexchange system would provide 70% of the annual non-CO2 heating load, and is economically viable compared to the propane base case. However, a lower cost natural gas base case would make the proposed geoexchange system economically unattractive. The heat produced as a byproduct of CO2 enrichment significantly limits the opportunity for a geoexchange system to generate a return on investment. The proposed geoexchange capacity is theoretically capable of providing approximately 80% of the annual heating system requirements, however heat from CO2 enrichment drastically reduces the number of hours the geoexchange system operates and limits the geoexchange contribution to only 21%.

2.0 Background This feasibility study was completed as part of a larger geoexchange benchmarking study conducted on behalf of the BC Ministry of Agriculture. This report should be read in conjunction with the Geoexchange Feasibility in Agricultural and Agri-Food Operations Benchmark Study to provide relevant context and background. The Benchmark report includes an overview of geoexchange technology and the results of geoexchange feasibility studies at several other agricultural facilities. It also includes an analysis of this facility under various theoretical scenarios that may be useful to the owner.



3.0 Scope of Work This study was carried out to meet the general requirements described in Professional Guidelines for Geoexchange Systems in British Columbia - Part 1 Assessing Site Suitability and Ground Coupling Options; Geoexchange BC, 2007. The scope of work to examine the site-specific options for adopting geoexchange for the subject agricultural operation included:


modeling heating and cooling loads and energy consumption for the operation with DOE2 energy modeling software;


estimating key thermal properties of shallow and deeper earth materials below the site to assess constructability of various types of GHX systems;




estimating the costs of installing the conceptual design and evaluating the financial viability of an investment in geoexchange technology for this application; and

recommending next steps based on the feasibility assessment.

4.0 Existing Operation 4.1 General Description

Site A is a 2,973 m2 (32,000 ft2) hot house built in 2006. It is used to grow organic long English cucumbers. The greenhouse is comprised of eight 6.4 m bays with 4.4 m gutters using a combination of twin-wall polycarbonate wall and polyethylene film roof glazing. The site is not currently serviced with natural gas and the nearest gas line is approximately 2 km away. Heat is currently provided by tanked propane. The greenhouse has a 200 A single phase electrical service from FortisBC and is two poles from a main power line. Irrigation water is provided from a surface water license on the adjacent Okanagan River. The water intake is in an oxbow off the river approximately 0.25 km from the greenhouse and unfiltered water is pumped to the building through an underground 3-inch main. The greenhouse is currently operated from mid-February to mid-October. During the growing season the greenhouse temperature is maintained between 23-27 °C.



A site visit to evaluate the structure, existing heating/cooling systems, and general site characteristics that may influence GHX options available was completed on November 28th 2011. 4.2 Current Heating and Cooling Systems

Heating is provided by three 400 MBH propane forced-air unit heaters that are approximately 3 years old. The combined capacity of 1,200 MBH is insufficient to maintain desired indoor temperatures beyond the current operating season. Cooling is achieved by passive ventilation, forced ventilation, and water fogging as required. 4.3 Proposed Expansions or Renovations

The owner plans to extend the greenhouse operations to year round growing and is currently evaluating the options to upgrade the climate control systems to meet the heating requirements for 12 month use. Upgrade plans include adding:

3 banks of lighting sufficient to provide a lighting intensity of 14,000 lux (20 hours/day in winter);

boiler and hydronic tube rail heat distribution system including top heat pipe;

Argus computer controls;

CO2 enrichment system (1,200 ppm target); and

Irrigation water preheating to 15‐16°C. In addition to expanding the season of operations, the site has space to expand the greenhouse to 3 or 4 ha. While additional greenhouse space is not planned in the immediate future, the owner has expressed specific concern that any heating system upgrades for the existing greenhouse also be scalable to allow for future greenhouse expansion. 4.4 Base Case Energy Analysis

The base case energy analysis corresponds to the current heating system serving the existing operation of the facility. The peak heating demand and annual heating energy consumption were estimated for the proposed upgraded greenhouse using DOE2 energy modeling software. Key modeling assumptions include:

Operation: Full year (12 month) with grow lights and CO2 enrichment

Weather file: Summerland, adjusted for Oliver temperatures

Utility rates1: Electricity FortisBC Elec 21, Gas FortisBC Gas 3, Propane at $0.5962/L

Building envelope: Polycarbonate U=0.59, SC=0.65. Poly U=0.71, SC=0.65, 1 AC/h infiltration, variable ventilation up to 12 AC/h

Lighting: 380 kW High Pressure Sodium lighting in 3 banks staged and controlled by ambient light sensor. Off 8pm – midnight.

Building Heat: Hot water rail system and 95% peak efficiency condensing boilers

1 See Appendix B for detailed utility rate structures.



Crop Heat: Minimum 64 kW (218 MBH) heating when OAT < 21 °C

CO2 enrichment: 24.5 kg/hr CO2 provided from boiler exhaust from midnight to 8 pm (i.e. all lit hours) for indoor target of 1200 ppm CO2.

Lighting and CO2 enrichment both have a strong influence on the facility’s heating requirements. The lights are scheduled to provide the target 14,000 lux lighting levels for 7,300 hours annually (20 hrs/day). Staging and daylight sensors result in the lights actually operating for approximately 3,600 full load hours equivalent. All the energy to run the lights is ultimately converted to heat within the greenhouse and reduces the amount of heat needed from the heating system. Under these assumptions lighting contributes approximately 50% of the total annual heating requirements of the greenhouse. The remaining heating that must be provided by the heating system is 2,129 GJ (2,018 MBtu) with a peak of 425 kW (1,450 MBH). Currently the only viable source of CO2 for enrichment at the site is the combustion of fossil fuels. To meet the CO2 enrichment of 1,200 ppm, 70% of the heating system load must be provided by the boiler. Therefore, we have assumed that only the heating requirement beyond that produced during CO2 enrichment (630 GJ / 597 MBtu) would be available to supply with a geoexchange system. The duration of heating system loads (presented as a percentage of the peak load) are presented in Figure 1. The plot is derived from historical climatic data for the specific region in conjunction with heat loss/gain performance assumptions for the facility. It shows how many hours in a year the heating system must operate at a given heating capacity. For example, it becomes clear from Figure 1 that 100% of the peak heating load is only required for very few hours each year (extreme left of the plot) but 10% of the peak heating load is required for most of the year. This information is useful for analysis and design purposes because it describes both the intensity of the heating load and the cumulative duration of different heating intensities throughout a typical year. Figure 1 shows both the total heating load profile (light green) and the net heating required from the heating system after the heat produced during CO2 production has been subtracted from the total (dark green). Both load profiles have distinct components separated by inflection points in the two curves. Section A of the curve (the steep portion at the left) is a typical heating load curve with a few hours at high loads and broadening out as the load drops. However, the curve is much steeper than would normally be seen with a typical building, with only 1,300 hours above 15% load. This is because greenhouses have very high peak loads due to the low insulating value of the glass/plastic. However, heat from the very high lighting levels offsets much of this load, as do the solar gains, resulting in a short heating season and the steep profile, which would go to zero at around 2,000 hours if it were not for the crop heat (Section B). Section B, the relatively flat portion of the curve, represents the minimum heating provided by crop heat. This is heating that is provided at all times, even when there is no other heating load, in order to keep the plants warm (or to provide minimum heating during shutdown). Crop heat is a small portion of the peak load (approximately 15%), but is required for most hours of the year. Section C (where the curves go to 0% of the peak) represents the hours when the crop heat is shut off (above 21 °C OAT) and there is no heating load at all.



Figure 1. Duration of heating requirements as a percentage of peak heating load for Site A

In summary, the peak demand and annual heating requirements for the proposed upgrade are estimated to be:

Peak heating demand: 425 kW (1,450,000 Btu/h)

Total annual building heat: 4285 GJ (4,061 MBtu) o Heat from lighting: 2,155 GJ (2,043 MBtu) o Heat from heating system: 2,129 GJ (2,018 MBtu)

- Heat from CO2 enrichment: 1,499 GJ (1,421 MBtu) - Additional heat required: 630 GJ (597 MBtu)

Monthly estimated heating system requirements are illustrated in Figure 2. Whereas Figure 1 shows the cumulative duration of loads at increasing levels of heating intensity, Figure 2 shows a month-by-month account of heating demand through a typical year. The total heating requirement in each month is shown divided into the heat generated during CO2 production (light green) and the remaining heat required from the heating system (dark green). Note that heat is required in all twelve months of the year.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

% o

f Pe

ak

Htg

Lo

ad

Annual Hours Above Load

Total Annual Heating

Non CO2 Heating

A

B

C



Figure 2. Monthly heating system requirements for Site A with proposed upgrades

The site is not currently serviced by natural gas. However, given the large proportion of the heating load that will require fossil fuel combustion to meet CO2 enrichment targets, we evaluated the base case energy consumption for both propane and natural gas fired boilers options. Annual energy consumption for the upgraded greenhouse is estimated to be:

Electricity: 1,421,423 kWh and

Propane: 86,814 Litres, or

Natural gas: 2,197 GJ Total annual GHG emissions are estimated to be 170 tonnes CO2e for the propane option and 146 tonnes CO2e for the natural gas option. To evaluate the effects on utility rate structures of a possible future expansion of the greenhouse, a second scenario in which a second greenhouse is built on the site was also considered. Energy consumption in the second scenario was assumed to be double the energy consumption estimated for the existing facility above. 4.5 Potential Energy Conservation Opportunities

Existing systems are quite simple and offer little opportunity for savings, although the propane heaters could be replaced with high efficiency condensing heaters if they were to remain. The proposed systems will be somewhat more complex, and there are some recommended measures that could be incorporated:

Use a condensing boiler for heating. The rail system should be designed for relatively low temperatures to enable condensing operation. If multiple boilers are used, ensure they can be staged off and isolated when not in use.

0

50

100

150

200

250

300

350

400

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

He

atin

g Lo

ad (M

BTU

)

Month

Additional Non-CO2 Heat Required

Heat Generated During CO2 Production



Thermal storage should be used to capture heat generated during CO2 production.

Use variable speed pumping. This will reduce pumping costs, as well as allow a larger supply and return temperature difference to be maintained during low loads, ensuring condensing operation of the boiler.

Although the lighting requirements will be dictated by plant requirements, it would be worth investigating whether more efficient lighting options are available, as lighting will be the largest energy consumer in the expanded operation. There may also be opportunities to reduce lighting use based on crop stage.

5.0 Site Characteristics The greenhouse is situated on approximately six hectares in the Okanagan River valley (Figure 3). Hillside and road side cuts observed during the site visit suggest near surface materials are granular alluvial deposits. The owner has experience excavating on site and estimates the ground water table to be approximately 1.8 m below ground surface. No water wells have been drilled on the site.

Figure 3. Aerial view of Site A showing potential area available for GHX construction shaded blue.



5.1 Subsurface Information

Information about soil, groundwater, and bedrock was gathered from the following sources:

Map 1736A, Geology Penticton, British Columbia; Geological Survey of Canada, 1989

Geological mapping incorporated within the BC Water Atlas online geographic information system

Lithology descriptions from water well drill logs for 16 water wells located within 500 m of the site accessed from the BC Water Atlas as shown in Figure 4

Previous direct observations of drilling conditions by Jeff Quibell at different sites in the Oliver area

Thermal conductivity and diffusivity values (key properties of soils and/or bedrock that govern how heat transfers through soil/bedrock) for shallow and deeper soils have been estimated with reference to Soil and Rock Classification for the Design of Ground-Coupled Heat Pump Systems, Electric Power Research Institute, 1989, and Ground-Source Heat Pumps; Design of Geothermal Systems for Commercial and Institutional Buildings, Kavanaugh and Rafferty, ASHRAE, 1997, and by direct professional experience.

Figure 4. Water well locations within 500 m of subject site.

SUBJECT SITE

A

B

C

D

E



Based on available climatic data and measurements we have taken in various parts of the southern Okanagan region, we expect the deep ground temperature at the site to be approximately 11.7 °C. 5.1.1 Upper Soils Shallow soils at the site (between a depth of 1.2 m to 2.1 m relevant for analysis of horizontal GHX systems) are expected to consist primarily of recent and Fraser Glaciation fluvial deposits of coarse and medium gravels, sands, and silt. GHX construction below the water table would be challenging in this setting and therefore we have assumed unsaturated conditions for the analysis with the following estimated thermal properties:

Thermal conductivity2: 0.87 W/m-°C (0.5 Btu/hr-ft-°F)

Thermal diffusivity3: 5.2 m2/day (0.48 ft2/day) 5.1.2 Bedrock The site is shown in Map 1786A to be underlain by a fault that roughly coincides with the channel of the Okanagan River in this segment of the Okanagan Valley. Accordingly, it's difficult to predict the true nature of the bedrock underlying the site, and it is likely the bedrock may be fractured and quite variable in physical properties. Based on the neighbouring bedrock types dominant on either side of the fault, bedrock underlying the site at depth is likely a granodiorite, which is a relatively hard and dense rock (similar to granite). A low density relatively soft volcanic bedrock layer may overlie the granodiorite. The presence of this rock layer is probably discontinuous and relatively thin. Because of the presence of the fault, thermal properties of bedrock cannot be reliably estimated at this site, though as a minimum they are expected to be:

Thermal conductivity: > 1.73 W/m-°C (1.0 Btu/hr-ft-°F)

Thermal diffusivity: > 8.5 m2/day (0.79 ft2/day) Bedrock formations typically have better heat exchange properties than unconsolidated soils due to their higher density. Note that bedrock can often be cost-effectively drilled for geoexchange purposes if the bedrock contact is at a relatively shallow depth (i.e., less than about 23 m bgs). When the bedrock contact is deeper than this, the transition from cased drilling techniques in the unconsolidated upper materials to open-hole rock drilling methods is often awkward and leads to higher GHX construction costs. Depth to bedrock is difficult to estimate for this site. Adjacent wells (see below) are mostly very shallow. Only one well report indicated contact with bedrock (at 14.6 m bgs) while the deepest well (50.3 m bgs) did not reach bedrock. Based on the contours of adjacent mountains and hills, there is a high probability that the depth to bedrock at the site is greater than 23 m bgs. 5.1.3 Groundwater The BC Water Resources Atlas shows the site to be near the edge of a high productivity, moderate demand, high vulnerability aquifer. Water well reports from the 16 wells within 500 m of the subject site (Figure 4) confirm that the upper soils are dominated by coarse and medium gravels with sands and silts. Deeper strata (to 50 m bgs) also include clay and bedrock was reported in one well log at 14.6 m bgs. The reported static water levels appear to confirm the expectation that ground water would likely be

2 Thermal conductivity is a measure of the ease with which heat can flow through a material. 3 Thermal diffusivity is a measure of a material’s conductivity relative to its density and specific heat capacity (the amount of heat required to change a material’s temperature by a given amount per unit mass).



encountered at +/- 1.8 m bgs. Only five well reports included driller’s estimate of well yield (noted in Figure 4). Well depths and yield estimates provided were:

A. 165 ft 10 gpm,

B. 48 ft 12 gpm,

C. 38 ft 20 gpm,

D. 12 ft 70 gpm, and

E. 10 ft 1000 gpm. Although one shallow, high yield well was noted, there is no other information to indicate that those well conditions could be recreated at the subject site. We anticipate groundwater production will be most similar to the lower yield wells reported. 5.1.4 Surface Water The owner currently holds water rights on the adjacent Okanagan River and uses that source for irrigation. The greenhouse uses approximately 900 to 1,350 L/day of irrigation water in winter and 14,000 L/day in the summer. Irrigation water is collected from a small oxbow off the main river north of the site. An existing 3-inch pipeline can deliver 3.8 L/s from the oxbow to the greenhouse. A second intake directly from the river can provide an additional 12.6 L/s. Surface water temperatures are expected to range seasonally from 0 °C to 25 °C based on water quality monitoring data collected under the Canada-British Columbia Water Quality Monitoring Agreement (Water Quality Assessment Of The Okanagan River Near Oliver, British Columbia (1990 – 2007) B.C. Ministry of Environment and Environment Canada, March 2009).

6.0 Geoexchange Options Appropriate sizing of a geoexchange system is required to balance installation costs versus annual energy savings. In commercial settings, geoexchange systems are often sized to serve only a base load portion of the heating capacity. Additional geoexchange capacity that would be required to handle rarely occurring peak loads often does not operate enough hours of the year to generate a return on investment. The duration of heating loads originally presented in Figure 1 are shown again in Figure 5 with the proposed heat pump capacity. Viewing the annual heating requirements in this way clearly illustrates that the greenhouse only experiences heating loads near the peak load for very short durations of the year. The greenhouse also has very long duration base heating loads to which geoexchange technology could be applied most effectively. For this facility a geoexchange system sized to meet approximately 15% of the peak load or roughly 64 kW (217,500 Btu/hr) is recommended.



Figure 5. Duration of heating requirements as a percentage of peak heating load for Site A

Greenhouse illustrating proposed heat pump capacity

Figure 5 also illustrates that a large portion of the heating that could be provided by the recommended geoexchange capacity is already covered by the heat generated during CO2 enrichment (light green shaded area below the proposed heat pump capacity line). Production of CO2 by the combustion of fossil fuels therefore significantly limits the opportunity for geoexchange equipment to generate a return on investment. The preferred sizing of a geoexchange system may also be influenced by the relative capacity of the heating distribution system to which it will be connected. In some cases, there may be a need to upgrade or increase the existing distribution system to match the temperature requirements of a geoexchange system. However, in this case, the hydronic rail distribution system with top heat pipe proposed in the base case scenario would not require any modifications to be compatible with the recommended geoexchange capacity. 6.1 GHX Option Comparison

The available GHX options (vertical closed-loop, horizontal closed-loop, groundwater open-loop, and

surface water open-loop) are evaluated in Table 1.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

% o

f Pe

ak

Htg

Lo

ad

Annual Hours Above Load

Total Annual Heating

Non CO2 Heating

Proposed Heat Pump Capacity



Table 1. Comparison of GHX Options at Site A

GHX OPTION FEASIBILITY

GHX Type Suitability Comments

H-GHX

Trenched horizontal

GHX (closed-loop)

High H-GHX systems can be very cost effective for certain ground conditions where low cost rapid trenching systems can install heat exchange (HX) pipe quickly and reliably. In many settings there is often insufficient space to install enough horizontal ground loop capacity to serve a meaningful portion of the peak loads. However, this site has approximately 4 ha immediately south of the building that are potentially available for H-GHX construction.

Care must be taken in designing and installing a H-GHX in the types of granular soils expected at this site. Granular materials by nature have limited areas of contact between one particle and the next and with the HX piping. Dry granular soils can therefore have very low heat transfer abilities and require considerably more HX piping to provide the equivalent heat exchange capacity as a H-GHX installed in saturated granular soils or other higher conductivity materials. Because it can be difficult to install HX piping below the water table and the saturation of soils can vary seasonally, it is safest to assume the H-GHX will experience dry conditions and design accordingly.

H-GHX Size Estimate The proposed geoexchange system would require an H-GHX area of approximately 6,782 m² to meet the capacity and annual heating parameters described above or about 15% of the available area.

Constructability The upper coarse gravel fill layer would prevent low cost methods such as the chain trencher method from being effective at this site. However clearing the area (perhaps in sections) with a bulldozer, laying HX piping in place and then recovering may be a moderate cost option for this site.

Possible Configuration To maximize possible use of the available area for additional H-GHX for future greenhouse expansion, an 18 m by 372 m area along the west property line is proposed. A total of 11,156 m of HX piping would be installed at 0.6 m spacing within the cleared area (30 circuits each 372 m long).

Merits Overall cost lower than vertical drilling option and some of the cost could be internal if the owner conducted the excavation work.

V-GHX

Drilled Vertical Borehole GHX (closed-loop)

Low The vertical borehole option (V-GHX) is inherently the most versatile of all options because it requires much less land area than H-GHX options, and is less sensitive to site specific conditions than open-loop groundwater. However, when other options are feasible, the V-GHX option is usually the most expensive.

Predicted depths to bedrock and loose unconsolidated overburden suggest a cased drilling method is likely required for this site. While construction of a vertical borehole GHX is achievable in this setting, it is likely to be far more





expensive than other options at the site.

GW-GHX

Groundwater water well

GHX (open-loop)

Low In areas with high groundwater production capabilities, GW-GHXs can often provide high capacity GHX at relatively low cost when compared with closed-loop options. The relatively constant temperature of deeper ground water sources can also lead to slightly higher GSHP efficiencies. However, the relatively fixed costs associated with water well drilling, development and testing usually makes GW-GHXs relatively more expensive for smaller geoexchange systems.

The hydrogeological review suggests a moderate to poor likelihood that adequate groundwater production could be cost effectively achieved at this site. High groundwater production in the area appears to be associated with very shallow granular materials and the adjacent Okanagan River. As such a GW-GHX in this setting would likely experience larger seasonal water temperature swings and therefore require higher flow rates than a deeper well system typically would. Likely available flow rates could potentially provide the GW-GHX requirements for the proposed geoexchange system; however this option is unlikely to provide the desired scalability for future greenhouse expansion. Based on this, no further consideration of this option is warranted.

SW-GHX

Surface water GHX

(open-loop)

Moderate The available surface water flow rates may be adequate for the recommended geoexchange capacity, however low minimum water temperatures may limit the operation of a SW-GHX at some times of the year. This may further reduce the potential operating time for a geoexchange system already restricted by the CO2 enrichment program. Therefore, a SW-GHX is not recommended for the winter heating season.

The warm water temperatures in the summer and existing infrastructure could provide a very low cost SW-GHX for base load crop heating in the spring, summer, and fall if a suitable load were available, however the majority of summer heating is covered by CO2 enrichment (see Figure 2). A SW-GHX would likely require relatively high maintenance and attention due to surface water quality, particularly suspended solids. Water filtration and regular heat exchanger cleaning may be required.

Based on information gathered to date, the most cost-effective GHX option regarding constructability and performance at this site is the horizontal closed-loop H-GHX option.



6.2 Proposed Conceptual Design

The proposed geoexchange system has the following features:

20 nominal tons of water-to-water heat pumps coupled to a hydronic rail distribution system and a horizontal closed-loop GHX as illustrated in Figure 6,

Geoexchange heating capacity of 68.3 kW (233 MBH; 16% of the peak heating system load) at design conditions,

Base case fossil fuel boiler capacity and rail distribution system to meet peak heating load,

Two stage hydronic temperature lift at heating outputs above heat pump capacity,

Annual geoexchange heating contribution of 70% of the annual non-CO2 heating requirements and 21% of the total annual heating system requirements.

The geoexchange system provides the first stage of heating beyond the heat generated as a byproduct of CO2 enrichment. Second stage heating requirements above 68.3 kW are provided by fossil fuel boilers. The heat pumps would be installed up-stream of the boilers. This configuration allows the heat pumps to provide all heating when possible and the first stage of a two stage temperature lift of the hydronic system fluid when additional heating capacity from the boilers is required, thereby maximizing the heat pump contribution to the annual heating requirements. The proposed rail system has enough heat exchange surface to allow the required heat transfer at the lower system temperatures required for heat pumps and condensing boilers. Although no changes to the rail distribution system are expected to be required, careful controls programming and system commissioning will be required to optimize the system efficiency.

Figure 6. Conceptual schematic of proposed geoexchange system

TO / FROM GREENHOUSE RAIL HEATING

SYSTEM

TO / FROM HORIZONTAL GHX

30 CIRCUITS, 36,600 FT TOTAL

HX PIPE.

BOILER 1 BOILER 2 HP 2 HP 1



Right-Suite® Universal Version 8.0.16 (Wrightsoft Corporation, Lexington, MA) and Ground Loop Design GLD 2009 (Thermal Dynamics, Maple Plain, MN) computation software were used for integrating information about the ground conditions, GHX configuration, and heating/cooling loads to calculate the required GHX size and capacity. The proposed GHX configuration and design parameters are:

Trench method: Full excavation by bulldozer

Trench depth (below surface): 1.5 m

Number of HX pipes: 30

Pipe to pipe separation: 0.6 m

Heat exchange pipe: 25 mm (1-inch) nominal diameter SDR 11

Piping circuit length: 372 m

Area Required for GHX: 6,782 m²

Antifreeze solution: 20% propylene glycol

GHX fluid flow: 0.25 L/s per nominal heat pump ton

Ground thermal properties: As indicated in previous section for shallow soils

Min Heat pump EWT: -1 °C

Heat pump heating COP: 3.2 at -1 °C EWT

Heat pump heating capacity: 63.9 kW (218,000 Btu/h) at minimum EWT

Heating only heat pump operation 6.3 Geoexchange Option Energy Analysis

The annual energy consumption and heating provided by the proposed 20 nominal ton geoexchange system were calculated using the same DOE2 model as the base case calculations. The proposed geoexchange system is expected to:

increase electrical consumption by 40,900 kWh;

reduce fossil fuel consumption by 18,918 L of propane or 479 GJ of natural gas; and

reduce GHG emissions by 28.2 or 23.1 tonnes CO2e for propane or natural gas scenarios respectively.

For the scenario in which a second greenhouse is built on the site, the changes in energy use noted above were doubled. Doubling the size of the greenhouse operations moves the facility into different utility rate categories and therefore influences the financial analyses presented below. 6.4 Geoexchange Options Cost Estimate

Preliminary additional cost estimates for the proposed geoexchange system beyond the base case costs

are summarized in Table 2.



Table 2 Estimated additional costs of proposed 20 nominal ton geoexchange system

Item Estimated Cost

Horizontal Ground Heat Exchanger $28,000 Heat Pumps (20 nominal tons) $20,000 Heat Pump Installation $6,000 Controls* $2,000 Engineering $5,000 Electrical Service Upgrade**

$5,000

Total $66,000

* In addition to proposed Argus Controls ** In addition to proposed service upgrade for lighting system The estimated additional costs in Table 2 were doubled for the scenario in which a second greenhouse is

built on the site.

7.0 Geoexchange Feasibility 7.1 Technical Feasibility

There are no significant technical challenges that would limit the installation of the proposed geoexchange system in this setting. The available land area is capable of providing ground heat exchange capacity for a greenhouse expansion of approximately six times the current greenhouse size under the proposed operating conditions. 7.2 Financial Feasibility

The financial costs of the base case and geoexchange system scenarios for the existing greenhouse are

summarized in Table 3. Under current conditions the proposed geoexchange system is considered

financially viable with a Chabot Profitability Index4 (CPI) of 0.86 and an IRR of 17.8% when compared to a

propane base case. However, comparing the proposed geoexchange system to a natural gas base case

scenario results in a CPI of -0.39 and an IRR of just 0.22%, and is therefore not considered financially

viable.

4 CPI = Net Present Value / Capital Cost. See Geoexchange Feasibility in Agricultural and Agri-Food Operations Benchmark Study for more information.



Table 3. Financial Evaluation of Proposed Geoexchange System for Existing Greenhouse

The financial costs of the natural gas base case and geoexchange systems for the scenario in which a

second greenhouse is built at the site are summarized in Table 4. Expansion to two greenhouses moves

the facility into a different electrical rate category resulting in lower blended electrical rates for both the

base case and geoexchange options. However, despite the lower electrical costs, the proposed

geoexchange system has a negative CPI and is not considered financially viable when compared to

natural gas.

Option Baseline - Propane

Boilers

Proposed GeoX with

Propane Boilers

Baseline - Natural

Gas Boilers

Proposed GeoX with

Natural Gas Boilers

Electricity Rate FBC 21 Comm FBC 21 Comm FBC 21 Comm FBC 21 Comm

Blended Electricity Cost ($/kWh) 0.090$ 0.090$ 0.090$ 0.090$

Natural Gas Rate - - FBC Rate3 FBC Rate2

Blended Natural Gas Cost ($/GJ) 9.71$ 9.90$

Blended Propane Rate ($/L) 0.5962$ 0.5962$

Heat Pump Capacity (nominal tons) 20 20

Nominal Heat Pump Capacity (MBH @

100° ELT, 30° EST for Closed Loop)

233 233

Nominal Heat Pump Capacity as % of peak 16% 16%

Load met by Heat Pump (Mbtu) 416 416

% non-CO2 load met by Heat Pump 70% 70%

% total load met by Heat Pump 21% 21%

Peak load met by Heat Pump (MBH) 291 291

Electricity Consumption (kWh) 1,421,422 1,462,328 1,421,422 1,462,328

Electricity Cost 127,340$ 131,211$ 127,340$ 131,211$

Natural Gas Consumption (GJ) 2,197 1,718

Natural Gas Cost 21,328$ 17,015$

Propane Consumption (L) 86,814 67,896

Propane Cost 51,758$ 40,480$

Total Energy Consumption (Mbtu) 6,934 6,620 4,852 4,991

Total Energy Cost 179,098$ 171,690$ 148,668$ 148,226$

Energy Cost Savings 7,408$ 442$

Additional Capital Cost 66,000$ 66,000$

Project Internal Rate of Return (%) 17.8% 0.22%

Chabot Profitability Index 0.86 -0.39

Annual GHG Emissions (tonnes CO2e) 142.6 113.6 119.0 95.2

Annual GHG Reduction (tonnes CO2e) 29.0 23.8

Potential Annual GHG Offset Value

($25/tonne CO2e)

724.09$ 595.93$



Table 4. Financial Evaluation of Geoexchange System for Expansion to Two Greenhouses

7.3 Conditions Required for Feasibility

All else being equal, any of the following conditions would lead to financial viability at a CPI of 0.3 for the existing greenhouse. Propane base case:

The proposed geoexchange system is financially viable under current conditions when compared to a propane base case.

Natural gas base case:

a blended electrical rate of $0.024 / kWh, or

a blended natural gas rate of $15.04 / GJ, or

a Renewable Heating Incentive of $34.13 / MWhth, or

a capital grant of $31,431

Option Baseline Doubled -

Natural Gas Boilers

Proposed GeoX

Doubled with

Natural Gas Boilers

Electricity Rate FBC 30 Comm FBC 30 Comm

Blended Electricity Cost ($/kWh) 0.077$ 0.077$

Natural Gas Rate FBC Rate3-2012 FBC Rate3-2012


Blended Propane Rate ($/L)

Heat Pump Capacity (nominal tons) 40

Nominal Heat Pump Capacity (MBH @

100° ELT, 30° EST)

466

Nominal Heat Pump Capacity as % of peak 16%

Load met by Heat Pump (Mbtu) 832

% non-CO2 load met by Heat Pump 70%

% total load met by Heat Pump 21%

Peak load met by Heat Pump (MBH) 582

Electricity Consumption (kWh) 2,842,845 2,924,657

Electricity Cost 219,404$ 225,452$

Natural Gas Consumption (GJ) 4,394 3,437


Propane Consumption (L)

Propane Cost

Total Energy Consumption (Mbtu) 9,704 9,983

Total Energy Cost 260,444$ 257,895$

Energy Cost Savings 2,549$

Additional Capital Cost 132,000$

Project Internal Rate of Return 3.0%

Chabot Profitability Index -0.31

Annual GHG Emissions (tonnes CO2e) 255.1 208.0

Annual GHG Reduction (tonnes CO2e) 47.2

Potential Annual GHG Offset Value

($25/tonne CO2e)

1,179.59$



8.0 Conclusions The energy modeling results and load profile information for Site A highlight several key heating characteristics of greenhouses employing artificial lighting and CO2 enrichment to maximize annual crop production:




The two primary factors affecting the economic viability of a geoexchange system in this setting are:

Fossil Fuel Price – The proposed geoexchange system is economically viable compared to the propane base case. However, the current large cost savings of natural gas versus propane makes it financially attractive to invest in bringing a natural gas service to the site. However, this investment may change if the price of natural gas were to increase. A lower cost natural base case makes the proposed geoexchange system unviable.

CO2 enrichment – The heat produced as a byproduct of CO2 enrichment significantly limits the opportunity for a geoexchange system to generate a return on investment. The proposed geoexchange capacity is theoretically capable of providing approximately 80% of the greenhouse’s annual heating requirement, however heat from CO2 enrichment drastically reduces the number of hours the geoexchange system operates and limits the geoexchange contribution to only 21% of the greenhouse’s annual heating requirement.

9.0 Recommended Next Steps A relatively low cost geoexchange system is technically feasible at this site. The economic benefits of the proposed geoexchange system are strongly dependent on the secondary fuel chosen for the facility and the use of fossil fuel combustion for CO2 enrichment. Therefore the recommended next steps are to:

Make final decision on CO2 requirements – Review the crop production benefits of CO2 enrichment at different CO2 levels relative to the energy costs estimated in this study and the potential costs to purchase and deliver a non-combustion source of CO2 for enrichment. Once the final CO2 requirements and relative costs of CO2 sources are known, the most cost effective or otherwise preferred source of CO2 can be selected.

If propane or a non-combustion source of CO2 is selected, a geoexchange system would provide significant energy cost savings and an attractive return on investment and warrants detailed design and costing.

If it is determined that bringing a natural gas service to the site is preferred over propane or a non-combustion source of CO2, a geoexchange system would not make economic sense at current energy costs.



If a lower level of CO2 enrichment is selected than has been modeled here, the geoexchange system could provide a larger portion of the heating load and the economic viability of the proposed geoexchange system should be reevaluated.

Appendix A Site B – Seasonal greenhouse


Site B – Seasonal greenhouse

Contents 1.0 Executive Summary ......................................................................................................................... 60

2.0 Background ..................................................................................................................................... 60

3.0 Scope of Work ................................................................................................................................. 60












6.3 Geoexchange Energy Analysis ..................................................................................................... 73






8.0 Conclusions ..................................................................................................................................... 76



The analysis and calculations presented in this report are provided for purposes of supporting preliminary evaluations. Note that the calculations presented herein are based on various estimates and assumptions and further site-specific investigations and energy analyses may be required to refine the analyses prior to preparing a detailed design. Detailed designs that may arise from the findings of this report will need to be carried out by fully qualified practitioners.




1.0 Executive Summary Site B is a 6,230 m2 (67,000 ft2) hot house used to grow peppers, tomatoes, and cucumbers on the Sunshine Coast of BC. The facility consists of two distinct but adjoining greenhouse structures, including a glass structure and a soft-wall poly structure. The site is not currently serviced by natural gas and the nearest gas line is approximately 15 km away. Heating is currently provided by an electric boiler on a low electric-plus electric rate and is supplemented by propane and waste oil boilers. Two large fields adjacent to the greenhouse are potentially available to install a horizontal GHX and two geoexchange system sizes (112 nominal tons and 56 nominal tons) were proposed based on the area available and the heating load profile. The larger geoexchange system would provide 55% of the annual heating load, however due to the very low electric utility rate at the facility this scenario did not meet the target profitability threshold. The smaller geoexchange system would provide 43% of the annual heating load and is economically viable compared to the base case.













recommending next steps based on the feasibility assessment.


Site B is a 6,230 m2 (67,000 ft2) hot house used to grow peppers, tomatoes, and cucumbers in a glass and poly facilities located north of Sechelt, BC on the Sunshine Coast. The greenhouse is situated on approximately 5.3 hectares. The facility consists of two distinct but adjoining greenhouse structures including a 4,370 m2 glass structure and a 1,670 m2 soft-wall poly structure. An additional 190 m2 is used for mechanical systems and other use. The glass structure is nearly square-shaped at 68 m by 64 m consisting of 10 equal width bays. The soft-wall poly structure is 61 m by 27.5 m consisting of four bays of varying width. The glass structure has single pane roof and double-pane walls. The soft-wall poly structure has 2 layers with airspace in the walls and ceiling. The site is not serviced by natural gas. The main natural gas trunk line serving the Sunshine Coast crosses offshore about 15 km south of the site to Texada Island where it continues on to serve Powell River to the north. Therefore, the nearest natural gas service to the site is about 15 km south. With sparse development in the area, there is slim likelihood for natural gas service to extend to the area of the site in the near future. A high capacity 600 Volt/3-phase BC Hydro electrical service serves the site. Water is supplied by an onsite water well (Water Well Tag Number 36310). The greenhouse is currently operated from early January to mid November (roughly 10.5 month growing season). During the growing season, the overnight minimum target temperature is 20 °C (though apparently during rare particularly cold periods the overnight temperatures are occasionally allowed to drop to 15 °C). A site visit to evaluate the structure, existing heating/cooling systems, and general site characteristics that may influence available GHX options was conducted on November 17th 2011. 4.2 Current Heating and Cooling Systems

Heat is provided by a 630 kW (input rating) electric boiler fed by a high capacity 600 Volt/3-phase electric service. A 1,674 MBH (490 kW) (input rating) forced draft propane boiler provides supplementary assistance to the electric boiler on an as-needed basis and provides emergency heating during power outages. The system also includes two oil-fired forced draft boilers which burn waste cooking oil. We understand these boilers operate intermittently during suitable cold periods when oil feedstock is available. We understand the oil-fired boilers are not required to meet the peak heating demands of the facility (i.e., the combined capacity of the electric and propane boilers is sufficient to meet the peak load). The oil boilers are intended for backup heating, to provide fuel flexibility, and to reduce the overall heating cost. Overhead direct-fired propane unit heaters are hung in the soft-wall poly greenhouse, although we understand these units are rarely used.



The main components of the heating system are all more than 20 years old. The electric boiler is date-stamped 1988, the propane boiler 1982, and the oil boilers are older. Heat is delivered to the greenhouses by a hydronic rail system consisting of steel pipe "rails" placed at ground level that distribute heated water from the boiler systems and dissipate the heat throughout the greenhouses. Within each 6.4 m bay of the glass greenhouse there are 8 hydronic rail pipes running the length of the greenhouse (4 out and back loops on each side of a central corridor) positioned at ground level. This amounts to a hydronic rail density of approximately 112 m of hydronic rail per 100 m2. Therefore, the total length of hydronic rail in the facility is estimated to be about 6,740 m. Heat is also delivered to the adjacent residence on the property. The greenhouse does not currently employ carbon dioxide enrichment, nor are grow lights used. A unique feature of this evaluation is the very low electric rate known as "electric plus" (e-plus) at a blended rate of $0.029/kWh. Cooling is provided only for one small room (less than 1,000 ft2 for cool storage). Relative to the scale of the heating load the cooling load is negligible. 4.3 Proposed Expansions or Renovations

Other than possible upgrades to the heating system, we are not aware of proposed expansions or renovations that would significantly alter the function of the greenhouse facility. Therefore, the feasibility study is focused on adapting geoexchange technology to the current operation. 4.4 Base Case Energy Analysis

The base case energy analysis corresponds to the current heating system serving the existing operation of the facility.



The peak heating demand and annual heating energy consumption were estimated using DOE2 energy modeling software. Key modeling assumptions include:

Operation: 10.5 month operation

Weather file: Vancouver

Utility rates1: Electricity BCH 1207 (Electric Plus); Propane $0.80/L; Waste oil collected at no charge.

Building Envelope: Total heated space 6,230 m2 Single glazing U-value (U) =1.11 Btu/hr-ft2-°F, shading coefficient (SC)=1.00 Double glazing U=0.57 Btu/hr-ft2-°F; SC =0.88 Double poly U=0.71 Btu/hr-ft2-°F, shading coefficient SC=0.65 1 air change per hour (AC/h), variable ventilation up to 12 AC/h. Suspended propeller fans are used for air circulation.

Boiler Plant: Electric boiler 96% full load efficiency (inc. 2% allowance for losses). Propane and oiler boilers 80% full load efficiency. - Boilers in heating plant are piped in series and hot water flows

through all boilers even when off, resulting in stack and jacket losses

Boiler Staging: Electric boiler provides first stage heating Propane boiler provides second stage Oil boilers assumed to be scheduled on for two weeks in January.

Heat Delivery: Hot rail water system.

Crop Heat: A reduced level of heating is distributed to the greenhouse at all times (including summer) to continuously maintain heat at the ground level.

The duration of heating system loads (presented as a percentage of the peak load) are presented in Figure 1. The plot is derived from historical climatic data for the specific region in conjunction with heat loss/gain performance assumptions for the facility. It shows how many hours in a year the heating system must operate at a given heating capacity. For example, it becomes clear from Figure 1 that 100% of the peak heating load is only required for very few hours each year (extreme left of the plot) but 10% of the peak heating load is required for most of the year. This information is useful for analysis and design purposes because it describes both the intensity of the heating load and the cumulative duration of different heating intensities throughout a typical year. The load profile has distinct components separated by inflection points in the curve. Section A of the curve (the steep portion at the left) is a typical heating load curve with a few hours at high loads and broadening out as the load drops. However, this only occurs at high loads above 75% of the peak, representing the period when there is cold weather and little solar gain and the greenhouse responds like a typical (although poorly insulated) building. Below this point the curve flattens out (Section B). The reason for this is the unusual loads and heat gains experienced in the greenhouse. The high solar gains offset heat loss much of the time, but the high solar gains are not directly related to outdoor temperature (although they roughly correspond in the sense that there are fewer hours of daylight




during winter). Another unique factor affecting the load profile is that the greenhouse is shut down during November and December when loads would otherwise be quite high. The heat is set down (but not off) for 1.5 months in November and December. This leads to an unusual profile where hours are spread evenly across the load range. The load profile would go to zero at around 3,700 hours if it were not for the crop heat which is represented by Section C (the relatively flat portion of the curve). This is heating that is provided at all times, even when there is no other heating load, in order to keep the plants warm (or to provide minimum heating during shutdown). Crop heat is a small portion of the peak load (approximately 12%), but is required for most hours of the year.

Figure 1. Duration of heating requirements as a percentage of peak heating load for Site B Greenhouse

In summary, the peak demand and annual heating requirements for the facility are estimated to be:

Peak heating demand: 868 kW (2,962,000 Btu/h)

Total annual building heat: 7,261 GJ (6,882 MBtu)

Crop heat component of the total: 1,395 GJ (1,320 MBtu) per year (19% of annual demand) The electric boiler meets 88% of the annual load, with the propane and oil boilers meeting 3% and 9% of the annual load, respectively. Monthly estimated heating system requirements are illustrated in Figure 2. Whereas Figure 1 shows the cumulative duration of loads at increasing levels of heating intensity, Figure 2 shows a month-by-month account of heating demand through a typical year. Note that heat is required in all twelve months of the year.

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Annual energy consumption for the greenhouse is estimated to be:

Electricity: 1,954,247 kWh,

Propane: 12,819 L, and

Oil: 21,109 L Total annual GHG emissions are estimated to be 126 tonnes CO2e. 4.5 Potential Energy Conservation Opportunities

Planning for energy system upgrades should consider strategies to reduce the magnitude of the load through energy conservation measures. Our review indicates that the following conservation measures warrant consideration:

The current piping arrangement in the mechanical room where the boilers are piped in series could be changed to reduce unnecessary heat losses and pumping losses.

Variable speed pumping for distributing hot water in the rail system could be explored.

The continuous low intensity "crop heat" stage of heating accounts for a significant portion of the annual heating load (19% of the overall annual heating). Opportunities to trim this heating component could translate into significant energy savings.

5.0 Site Characteristics The greenhouse is situated on approximately 5.3 ha (Figure 3). The site is nearly flat and on an alluvial plain at the end of an estuary. The elevation of the site is likely only about six metres above sea level. Limited observations of soil at the surface and discussion with the owner suggest the shallow soils are

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predominantly fine-grained silts, clays, and fine sands. There are prominent bedrock exposures in areas near the site, suggesting that bedrock likely occurs at fairly shallow depth below the ground surface.

Figure 3. Aerial view of Site B Greenhouse showing potential areas available for GHX construction

shaded blue.




Lithology descriptions from water well drill logs for 4 water wells located within 500 m of the site accessed from the BC Water Atlas database as shown in Figure 4, including one well on the farm site (Well A)

Thermal conductivity and diffusivity for shallow and deeper soils have been estimated with reference to Soil and Rock Classification for the Design of Ground-Coupled Heat Pump Systems, Electric Power Research Institute, 1989, and Ground-Source Heat Pumps; Design of Geothermal Systems for Commercial and Institutional Buildings, Kavanaugh and Rafferty, ASHRAE, 1997, and by direct professional experience.

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Based on available climatic data and measurements we have made in various parts of the South Coast Region, we expect the deep ground temperature at the site to be approximately 11 °C. 5.1.1 Upper Soils Shallow soils at the site (between a depth of 1.2 m to 2.1 m relevant for analysis of horizontal GHX systems) are expected to consist primarily of fine-grained alluvial sediments. Standing water observed on the north part of the site and the elevation just slightly above sea level in the nearby estuary suggest that the depth to water table is quite shallow. No cobble or boulder sized stones were observed in the limited observations of surface soils made during the site visit. Estimated thermal properties of the soils:

Thermal conductivity2: 1.7 W/m-K (1.0 Btu/hr-ft-°F)

Thermal diffusivity3: 7.5 m2/day (0.7 ft2/day)




5.1.2 Bedrock The bedrock underlying the site is mapped as granodiorite. Thermal properties for granodiorite are provided below:

Thermal conductivity: 2.1 to 3.5 W/m-K (1.2 to 2.0 Btu/hr-ft-°F)

Thermal diffusivity: 8.6 to 14.0 m2/day (0.8 to 1.3 ft2/day) Bedrock formations typically have better heat exchange properties than unconsolidated soils due to their higher density. Note that bedrock can often be cost-effectively drilled for geoexchange purposes if the bedrock contact is at a relatively shallow depth (i.e., less than about 23 m bgs). When the bedrock contact is deeper than this, the transition from cased drilling techniques in the unconsolidated upper materials to open-hole rock drilling methods is often awkward and leads to higher GHX construction costs. 5.1.3 Groundwater High capacity groundwater production (13 to 25 L/s) would be required to provide an open loop groundwater source for this facility. None of the water wells shown in Figure 4 provide any indication in their respective well logs to suggest high capacity potential. Well depths and yield estimates for these wells are summarized below:

Well A 39 ft (bedrock not encountered) No yield information

Well B 160 ft (bedrock at ground surface) 10 USgpm

Well C 31 ft (bedrock not encountered) No yield information

Well D 175 ft (bedrock encoutered at 23 ft) 15 USgpm A notation on the log for the farmsite well (Well A) suggests a high iron concentration. The owner also mentioned iron taste and odour related to the well water, and there was evidence of iron staining around a water storage tank on the farm. The low elevation of the site relative to the nearby estuary also suggests the possibility of brackish groundwater. 5.1.4 Surface Water The site is located adjacent to a tidewater estuary. However, observations during the site visit and subsequent review of aerial photography indicate that the estuary is shallow and during low tide mudflats are likely exposed.

6.0 Geoexchange Options Appropriate sizing of a geoexchange system is required to balance installation costs versus annual energy savings. In commercial settings, geoexchange systems are often sized to serve only a base load portion of the heating capacity. Additional geoexchange capacity that would be required to handle rarely occurring peak loads often does not operate enough hours of the year to generate a meaningful return on investment. The duration of heating loads originally presented in Figure 1 is shown again in Figure 5 with the proposed heat pump capacities. Viewing the annual heating requirements in this way clearly illustrates



that the greenhouse only experiences heating loads near the peak load for very short periods in a typical year. Figure 5 also illustrates that that the greenhouse also has very long duration base heating loads to which geoexchange technology is best suited (the long, flat portion of the curve extending to the right of the figure).

For this facility, we have examined two geoexchange system scenarios:

Scenario 1: Sized to meet 28% of the peak heating load with a heat pump plant consisting of four 28 nominal ton heat pumps (112 nominal ton installed capacity).

- Peak heating delivered by geoexchange: 305 kW (1,042 MBH) - Annual heat delivered by geoexchange: 3,968 GJ (3,761 MBtu) - Equivalent full load hours: 3,609 EFLh

Scenario 2: Sized to meet 14% of the peak heating load with a heat pump plant consisting of two 28 nominal ton heat pumps (56 nominal ton installed capacity).

- Peak heating delivered by geoexchange: 153 kW (521 MBH) - Annual heat delivered by geoexchange: 3,092 GJ (2,931 MBtu) - Equivalent full load hours: 5,626 EFLh

Figure 5. Duration of heating requirements as a percentage of peak heating load for Site B Greenhouse

illustrating proposed heat pump capacities

The appropriate sizing of a geoexchange system may also be influenced by the relative capacity of the heating distribution system to which it will be connected. Geoexchange heat pumps deliver heat at a lower temperature (typically 45 to 55 °C) than combustion boilers (typically 70 to 80 °C), which means that in some cases the hydronic rail system would need to be upgraded or expanded to deliver enough

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heat to meet the demand while maintaining lower rail temperatures that are compatible with geoexchange heat pumps. In this case, our calculations indicate the hydronic rail system temperatures for the existing system can be compatible with the heat pumps when loads are less than 62% of the peak load. When the heating loads are greater than 62% of peak load, the hydronic rail temperatures will need to be too high for the heat pumps to operate efficiently. Therefore, the operation of the system has been modeled such that the heat pumps would disengage when heating loads exceed 62% of peak load. Figure 5 indicates that loads exceeding 62% of peak occur about 1,100 hours per year during which time the heat pumps would not operate. The hydronic rail system could be expanded by adding a second level of hydronic rail piping in the greenhouse which would allow 100% peak heating loads to be met while maintaining rail temperatures in a compatible range with the heat pumps. However, the added cost may not be worthwhile to gain the additional 1,100 hrs (15% gain) of heat pump operation. 6.1 GHX Option Comparison

The available GHX options (vertical closed-loop, horizontal closed-loop, groundwater open-loop, and surface water open-loop) are evaluated in Table 1.

Table 1. Comparison of GHX Options at Site B Greenhouse



H-GHX

Trenched horizontal

GHX (closed-loop)

High H-GHX systems can be very cost effective for certain ground conditions where low cost rapid trenching methods can install heat exchange (HX) pipe quickly and reliably. In many settings there is often insufficient space to install enough horizontal ground loop capacity to serve a meaningful portion of the peak loads. However, many agricultural sites, including this site, have relatively large available areas surrounding the heated facility. The combined Areas A and B as shown in Figure 3 comprise an area of approximately 2.4 ha.

The chain-trencher method is among the most cost-effective methods for H-GHX installation. Based on information gathered for shallow soils at the site, the chain trencher method is expected to be suited for the soils. This method excavates narrow trenches to a depth of about 1.8 m and two heat exchange pipes are placed at the bottom of each trench and then backfilled.

H-GHX Size Estimate For Scenario 1 using the chain-trencher method, a land area of approximately 23,226 m² would be required to accommodate an H-GHX to meet the GSHP capacity and annual loads (this would occupy all of combined area of Area A + Area B) as shown in Figure 3. For the reduced heat pump capacity of Scenario 2, about 13,935 m² land area would be required (this could be accommodated on Area A alone and avoid disturbing Area B).

Constructability The chain trencher method is expected to be suitable. If conditions do not allow chain trench methods then trenching by excavator could be considered





with somewhat higher associated costs. This analysis assumes that there are no parts of Areas A & B where bedrock occurs at a depth less than 6 ft.

Merits Lower cost than V-GHX option and some of the cost could be internal if the owner conducted the excavation work.

V-GHX


Low The vertical borehole option (V-GHX) is inherently the most versatile of all options because it requires much less land area than H-GHX options, and is less sensitive to site-specific conditions than open-loop groundwater. However, when other options are feasible, the V-GHX option is usually the most expensive of all options.

Bedrock is expected to be encountered at relatively shallow depth at the site. The bedrock is expected to be granodiorite which is relatively hard. Although the thermal properties of granodiorite are expected to be quite good, the cost to drill will be considerable. Based on information gathered to date about site conditions, the cost for implementing V-GHX is expected to be at least a factor of 2 to 3 greater than for H-GHX to deliver equivalent heat exchange capacity.

GW-GHX


GHX (open-loop)

Low In areas with high groundwater production capabilities, GW-GHXs can often provide high capacity GHX at relatively low cost when compared with closed-loop options. The relatively constant temperature of deeper ground water sources can also lead to slightly higher GSHP efficiencies.

For System Scenario 1 over 12.6 L/s of groundwater production would be required and for Scenario 2 over 6.3 L/s would be required. Review of hydrogeological information suggests poor likelihood that groundwater production of this scale could be developed at this site. Furthermore, anecdotal information about high iron concentration in local groundwater leads to concerns about high fouling potential.

SW-GHX

Surface water GHX

(open-loop)

Moderate Although the site is located near an estuary, the shallow water and mudflats of the estuary are not well suited to surface water heat exchange. Shallow water estuary marine environments are often considered sensitive aquatic habitats and approvals from regulatory authorities would be required to develop heat exchange infrastructure.

There is also a small pond at the north boundary of the property (identifiable in Figure 3). Some heat exchange capacity could be developed with the current pond. If the pond size were increased it is possible that the entire heat exchange capacity could be developed with a pond heat exchanger. In discussion with the Owner, the pond level fluctuates during the year and there is a distinct risk that the pond levels may not be reliable for providing long-term sustainable source of heat. Further study of pond potential would need to be undertaken before this option could be recommended.



Based on information gathered to date, the most cost-effective GHX option regarding constructability and performance at this site is the trenched horizontal closed-loop H-GHX option. 6.2 Proposed Conceptual Design


112 nominal tons (Scenario 1) or 56 nominal tons (Scenario 2) of water-to-water heat pumps in increments of 28-ton modules coupled to a hydronic rail distribution system and a horizontal closed-loop GHX as illustrated in Figure 6,

Geoexchange heating capacity satisfies approximately 28% and 14% of the peak heating load for Scenarios 1 and 2, respectively. These capacities allow the geothermal heat pump system to meet 55% and 43% of the annual heating load for Scenarios 1 and 2, respectively.

Staging priority: 1. Geoexchange heat pumps 2. Electric boiler 3. Propane-fired boiler 4. Oil-fired boiler (since oil is the lowest cost source of heat - but not always available - the

system could be designed so that the staging priority of the oil-fired boiler could be raised when waste oil stock is plentiful)

Heat pumps programmed to disengage during periods when the heating load is greater than 62% of peak load.

The piping connecting the boilers would be re-configured in the injection-style arrangement as shown in Figure 6 to eliminate the existing series connections between the boilers.


TO / FROM EXISTING

GREENHOUSE RAIL HEATING

SYSTEM


100 CIRCUITS, 30,000 FT OF

TRENCH.

PROPANE BOILER

ELECTRIC BOILER HP 2 HP 1

USED OIL BOILER



Right-Suite® Universal Version 8.0.16 (Wrightsoft Corporation, Lexington, MA) and/or Ground Loop Design GLD 2009 (Thermal Dynamics, Maple Plain, MN) computation software were used for integrating information about the ground conditions, GHX configuration, and heating/cooling loads to calculate the required GHX size and capacity. The proposed GHX configuration and design parameters are:

Trench method: Excavated trench (chain trencher or excavator method)

Trench depth (below surface): 1.8 m with two pipes per trench buried at least 1.5 m

Trench to trench separation: 2.44 m


Heating Loads: As indicated in previous section for Scenarios 1 and 2 Heating only operation

Ground thermal properties: As indicated for surficial soils in previous section

Minimum entering source temperature to heat pump: -2 to -1 °C

Heat Pump COP: 3.2 at -1 °C entering source temperature

GHX fluid: Water solution with 20% propylene glycol

Overall trench length: Scenario 1: Approximately 9,144 m of trench Scenario 2: Approximately 5,182 m of trench

Area Required for GHX: Scenario 1: Approximately 23,226 m² Scenario 2: Approximately 13,935 m²

6.3 Geoexchange Energy Analysis

The annual energy consumption for System Scenarios 1 and 2 were calculated using the same DOE2 model as the base case calculations. Summary of performance expectations for System Scenario 1 as compared to base case:

Electrical consumption is expected to decrease by about 865,000 kWh per year as a result of less reliance on the electric boiler.

Reduced electricity consumption translates to $24,300 in annual savings.

Propane and oil consumption remains virtually unchanged since the combustion boilers operate as supplemental heating during periods beyond which the geoexchange heat pumps can assist.

GHG reductions amount to about 23 tonnes CO2e per year (a relatively small reduction because the energy savings are in the form of electricity savings and the GHGs associated with electricity generation in BC are relatively low).

Summary of performance expectations for System Scenario 2 as compared to base case:

Electrical consumption is expected to decrease by about 682,000 kWh per year as a result of less reliance on the electric boiler.

Reduced electricity consumption translates to $19,200 in annual savings.



Propane and oil consumption remains virtually unchanged since the combustion boilers operate as supplemental heating during periods beyond which the geoexchange heat pumps can assist.

GHG reductions amount to about 18 tonnes CO2e per year (a relatively small reduction because the energy savings are in the form of electricity savings and the GHGs associated with electricity generation in BC are relatively low).

6.4 Geoexchange Options Cost Estimate

Preliminary additional cost estimates for the proposed geoexchange system beyond the base case costs are summarized in Table 2a and 2b. Table 2a Estimated additional costs of proposed Scenario 1 (112 nominal ton geoexchange system)

Item Estimated Cost

Horizontal Ground Heat Exchanger $112,000 Heat Pumps (112 nominal tons) $200,000 Heat Pump Installation $70,000 Controls $10,000 Engineering $39,000 Total $431,000

Table 2b Estimated additional costs of proposed Scenario 2 (56 nominal ton geoexchange system)

Item Estimated Cost



There are no specific technical challenges that would limit the installation of the proposed geoexchange system in this setting. The available land area is capable of providing ground heat exchange capacity for meeting the loads described in the conceptual design. The Owner will need to consider whether burial of piping on a large part of the farm acreage is compatible with long-range plans for the farm. 7.2 Financial Feasibility

The financial costs of the base case and geoexchange system scenarios for the greenhouse are summarized in Table 3. Under current conditions, the proposed geoexchange system scenarios have a Chabot Profitability Index4 (CPI) of 0.19 and 0.47, and an IRR of 9.8% and 13.4% for Scenario 1 and Scenario 2 respectively. A target CPI of 0.3 has been selected as the threshold for economic viability in the Benchmarking Study and only Scenario 2 meets this target.




Table 3. Financial Evaluation of Proposed Geoexchange System for Existing Greenhouse

Option Baseline Geoexchange to

meet 28% of

peak load

Geoexchange to

meet 14% of

peak load

Climate Vancouver Vancouver Vancouver

Electricity Rate BCH 1207 E+ BCH 1207 E+ BCH 1207 E+

Blended Electricity Cost ($/kWh) 0.029$ 0.029$ 0.029$

Natural Gas Rate

Blended Natural Cost ($/GJ)

Blended Propane Rate ($/L) 0.8385$ 0.8385$ 0.8385$

Heat Pump Capacity (nominal tons) 112 56

Heat Pump Capacity (MBH @ 100° ELT, 30° EST) 844 422

Nominal Heat Pump Capacity as % of peak 28.5% 14.2%

Heat Pump cut-off point (MBH) 1844 1844

Heat Pump cut-off point (%) 62% 62%

Load met by Heat Pump (Mbtu) 3761 2931

% total load met by Heat Pump 55% 43%

Peak load met by Heat Pump (MBH) 1042 521

Electricity Consumption (kWh) 1,954,247 1,089,303 1,272,142

Electricity Cost 56,326$ 32,021$ 37,158$

Natural Gas Consumption (GJ)

Natural Gas Cost

Propane Consumption (L) 12,819 12,877 12,877

Propane Cost 10,749$ 10,797$ 10,797$

Oil Consumption (L) 21,109 20,481 20,867

Oil Cost -$ -$ -$

Total Energy Consumption (Mbtu) 7,754 4,780 5,418

Total Energy Cost 67,075$ 42,818$ 47,955$

Energy Cost Savings 24,256$ 19,119$


Project Internal Rate of Return 9.8% 13.4%

Chabot Profitability Index 0.19 0.47

Annual GHG Emissions (tonnes CO2e) 126.4 103.1 108.8

Annual GHG Reduction (tonnes CO2e) 23.3 17.6

Potential Annual GHG Offset Value ($25/tonne CO2e) 581.29$ 440.62$




All else being equal, the following conditions would lead to financial viability at a CPI of 0.3 for the greenhouse. Scenario 1:

a blended electrical rate of $0.033 / kWh or higher, or


the project crosses the profitability threshold when a 5% discount rate is used for the capital grant calculation. A Capital grant is no longer required at this discount rate.

Scenario 2:

The proposed 56 ton geoexchange system is economically viable under current conditions.

8.0 Conclusions The study draws the following conclusions:

It is technically feasible to adapt geoexchange heating for the Site B Greenhouse.

The horizontal trenched method of ground exchange appears most suited for this site, though there may be opportunity to develop an expanded pond in the north part of the site to accommodate a pond heat exchanger.

Geoexchange can be incorporated into the facility's existing heating plant in a fairly straightforward manner.

An acceptable business case can be made for implementing geoexchange. The smaller 56 nominal ton system Scenario 2 offers a stronger business case than the larger 112 nominal ton Scenario 1.

Scenario 2 occupies a lot less land area and requires a lot less capital than Scenario 1, while offering most of the energy and cost savings.

An unusual aspect of this application is the large electric boiler and the low electric rates for operating the boiler.

Application of geoexchange at this site offers limited GHG reductions because the geoexchange operation is displacing electric boiler operation and the displaced BC Hydro electricity has a relatively low GHG emission factor assigned to it.

9.0 Recommended Next Steps We recommend the following steps:

The Owner will need to consider whether occupying a large part of the farm with buried heat exchanger is compatible with long-term plans.

The Owner will need to ensure that changes to the heating system will not disqualify eligibility for the e-plus electric rate.

The conceptual design will need to be detailed before it can be constructed. Verification of the ground conditions assumed in this analysis will be an important initial step to detail the design.

Appendix A Site C – Poultry Barn


Site C – Poultry barn Table of Contents 1.0 Executive Summary ......................................................................................................................... 78

2.0 Background ..................................................................................................................................... 78

3.0 Scope of Work ................................................................................................................................. 78












6.3 Geoexchange Energy Analysis ..................................................................................................... 92






8.0 Conclusions ..................................................................................................................................... 94







1.0 Executive Summary Site C is a 75,000 bird broiler barn operation with plans to expand to 100,000. The two-level 4,740 m2 (51,000 ft2) facility is located in the Fraser Valley. The operation is year-round and conforms to an 8-week growing cycle with 6.5 cycles per year. Each cycle consists of 6 growing weeks with two weeks for cleaning and preparation at the end of each cycle. Temperature control is critical to maintain growing conditions and to reduce mortality. Warmer temperatures are required at the beginning of the cycle (starting at 35 °C) and then the temperature is progressively ramped down as the cycle progresses. The facility is currently served by natural gas and is currently heated with a simple natural gas radiant brooder heater system. It is technically feasible to adapt geoexchange heating for the Site C Poultry Barn, and of the various options available for ground heat exchange, a horizontal trenched approach is most suitable. However, while geoexchange is technically feasible and capable of significantly reducing natural gas consumption and GHG emissions, the study concludes that the application of geoexchange in this application and site setting does not meet the profitability criteria established for the study. There are two main reasons this application fails to meet profitability:

The geoexchange system cannot be adapted to use an existing heat distribution system within the barns. Therefore a completely new and separate heat distribution needs to be added within the barns.

The prevailing very low cost of natural gas constrains profitability prospects for this application.

This same application compared to a propane base case is profitable.













recommending next steps based on the feasibility assessment


Site C is a 75,000 broiler barn operation located in the Fraser Valley. The existing operation consists of two parallel long and narrow barns with a connecting structure joining the two barns. Each of the barns has two levels. One of the barns is 122 m by 12.8 m, while the second barn is 64 m by 12.8 m so the total footprint area of the barns is approximately 2,370 m2 (25,500 ft2). Accounting for the two levels, the total floor area is approximately 4,740 m2 (51,000 ft2). The shorter barn was constructed with extended footings and floor to allow for future expansion. We understand it could be lengthened by as much as 70 m and this additional length would accommodate an additional 30,000 birds. The structures are of common wood frame construction. The walls are 2x6 frame with R-20 batt insulation and the roof is R-40. Windows which are only in the connecting structure between the barns are double glazed with vinyl frames. Construction is tight for careful temperature control. The operation is year-round and conforms to an 8-week growing cycle with 6.5 cycles per year. Each cycle consists of 6 growing weeks with two weeks for cleaning and preparation at the end of each cycle. Temperature control is critical to maintain growing conditions and to reduce mortality. Warmer temperatures are required at the beginning of the cycle (starting at 35 °C) and then the temperature is progressively ramped down as the cycle as follows:

Week 1 Begin at 35 °C ramping down to 30 °C

Week 2 30 °C

Week 3 28 °C

Week 4 26.5 °C

Week 5 25 °C



Week 6 23 °C

Week 7 Turned down for cleaning

Week 8 Turned down for cleaning The site is serviced by Fortis BC natural gas and BC Hydro electrical connections. Water is supplied by an onsite water well. A site visit was conducted on January 9th 2011 to meet the Owner and view the operation, including observations of:

the barn structures;

existing heating/cooling systems; and

general site characteristics affecting available ground heat exchanger (GHX) options. 4.2 Current Heating and Cooling Systems

The current heating system is a very simple natural gas system consisting of multiple evenly-spaced brooder heaters (similar in principle to a common patio heater) in combination with a direct gas-fired unit heater for each barn floor area. We understand that almost all of the heating is provided by the radiant heaters and the unit heaters rarely operate only to provide supplemental assistance during short intense cold periods. The connected space between the barns is heated by electric baseboard heaters. Barn ventilation is provided by wall-mounted propeller exhaust fans positioned at regular intervals on

one of the long walls of each barn, with continuous-length dampered air intake slots on the opposite

walls. The exhaust air and damper are modulated to control space temperature and humidity, static

pressure, and ammonia levels via a computer controller.

Control of the space temperatures is also computer controlled to maintain prescribed temperatures

during the stages of the growing cycle.

Cooling, which is required only intermittently during the hottest summer days, is provided by water mist

nozzles at the ventilation intake slots.

4.3 Proposed Expansions or Renovations

As discussed above, expansion of the shorter barn is planned which would increase the production by an additional 30,000 birds. We understand the structure and systems included in the expansion are planned to be consistent with the existing barns. 4.4 Base Case Energy Analysis

The base case energy analysis corresponds to the current heating system serving the existing operation of the facility. Peak heating demand and annual heating energy consumption were estimated using DOE2 energy modeling software. Key modeling inputs to the DOE2 energy software include:



Model assumptions

Operation: Year-round operation (6.5 cycles per year)

Weather file: Abbotsford

Utility rates1: Electricity BCH 1151 (Residential Farm), Natural gas FBCGas 2

Internal gains: Chickens: ranges from 1.2 W to 14 W per chicken through growing cycle. Lighting: resulting from 0.09 W/ft² lighting, turned down to 25% after first week, and turned off from midnight to 6am.

Building envelope: 0.038 cfm/ft² wall area infiltration R-20 wood frame walls and R-40 ceiling Variable ventilation up to 216,000 CFM, minimum ventilation staged from 3,000 CFM to 38,000 CFM through growing cycle.

Efficiency of Existing

System: Radiant brooder heaters: 100% efficiency because they are unvented (no loss of heat by exhaust venting). The gas unit heaters are less efficient (about 80%), but because they rarely operate the overall efficiency is assumed to be unaffected since almost all of the heating is provided by the radiant brooder heaters.

The duration of heating system loads (presented as a percentage of the peak load) are presented in Figure 1. The plot is derived from historical climatic data for the specific region in conjunction with heat loss/gain performance assumptions for the facility. It shows how many hours in a year the heating system must operate at a given heating capacity. For example, it becomes clear from Figure 1 that 100% of the peak heating load is only required for very few hours each year (extreme left of the plot) but 10% of the peak heating load is required for approximately half of the year. This information is useful for analysis and design purposes because it describes both the intensity of the heating load and the cumulative duration of different heating intensities throughout a typical year. The load profile is a fairly consistent curve, with no major deviations. Although the shape of the profile is similar to a typical building heating profile, in fact it is influenced more by operation than by outdoor temperature. Section A, with loads above 50%, is largely a pickup load caused by increasing the temperature to 35 °C for the first week of the growing cycle. The remainder of the curve (Section B) responds to changes in ventilation rate, space temperature, heat gains from the chickens, and outdoor temperature and relative humidity.




Figure 1. Duration of heating requirements as a percentage of peak heating load for Site C Poultry

Barn

Total annual heating load is 1,745 GJ (1,654 MBtu) with a peak of 702 kW (2,396 MBH). Equivalent full load heating (EFL) hours are a very short 690 hours, although if the pickup load above 50% is discounted, the full load heating hours are a more typical 1,380 EFL hrs. Monthly estimated heating system requirements are illustrated in Figure 1. Whereas Figure 1 shows the cumulative duration of loads at increasing levels of heating intensity, Figure 2 shows a month-by-month account of heating demand through a typical year. Monthly heating requirements vary according to the combination of the outdoor temperature and the indoor temperatures required at different stages of the growing cycle.

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Figure 2. Monthly heating requirements for Site C Poultry Barn

Annual energy consumption for the poultry barn is estimated to be:

Electricity: 80,944 kWh and

Natural gas: 1,745 GJ. Total annual GHG emissions are estimated to be 90 tonnes CO2e. 4.5 Potential Energy Conservation Opportunities

Planning for energy system upgrades should routinely consider strategies to reduce the magnitude of the load through energy conservation measures. Our review indicates limited opportunities for adopting practical energy conservation measures. Recovery of heat lost to ventilation would likely provide the most significant energy conservation improvement. However, the configuration of the existing system with the continuous-slot intake on one wall of the barn and the exhaust fans positioned on the opposite side of the barn does not readily lend itself to application of typical heat recovery ventilator (HRV) arrangements, where the heat recovered from the ventilation discharge is introduced to the intake. Customized HRV arrangements could be considered for this application, but would be beyond the scope of a geoexchange-specific feasibility assessment.

5.0 Site Characteristics The poultry barn operation is situated on a parcel of approximately eight hectares (Figure 3). The site is flat lying on alluvial floodplain deposits of the Fraser River. With the flat topography, there are limited opportunities, such as cut banks or road cuts, to view exposed soil profiles on or immediately adjacent

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to the site. A channel feature diagonally bisects the site south of the barns, but the channel is too heavily vegetated to view a clear indication of the soil profile. Information from the Owner suggests shallow soils in the upper 1.5 to 3 m consist predominantly of silt (upper topsoil consists of silt loam topsoil). Apparently soils on neighbouring lands to the east are known to have relatively shallow gravel layers that apparently do not extend to the subject site. There were no indicators of shallow bedrock outcrops observed near the site during the site visit.

Figure 3. Aerial view of Site C Poultry Barn showing potential area for GHX construction shaded blue.




Lithology descriptions from BC Ministry of Environment water well drill logs for 4 water wells located within 500 m of the site, accessed from the BC Water Atlas database shown as Wells A, B, C, and D in Figure 4

Thermal conductivity and diffusivity values (key properties of soils and/or bedrock that govern how heat transfers through soil/bedrock) for shallow and deeper soils were estimated with reference to Soil and Rock Classification for the Design of Ground-Coupled Heat Pump Systems, Electric Power Research Institute, 1989, and Ground-Source Heat Pumps; Design of Geothermal Systems for Commercial and Institutional Buildings, Kavanaugh and Rafferty, ASHRAE, 1997, and by direct professional experience.

0 metres 100




Based on available climatic data and measurements we have made in various parts of the South Coast and Fraser Valley Region, we expect the deep ground temperature at the site to be approximately 10 to 11 °C. 5.1.1 Upper Soils Shallow soils at the site (between a depth of 1.2 m to 2.1 m relevant for analysis of horizontal GHX systems) are expected to consist primarily of alluvial-deposited sediments. Based on information provided by the Owner, the soils are expected to be predominantly fine-grained (mostly silt but also likely accompanied by some clay and fine sand). Estimated thermal properties of the soils:


Thermal diffusivity3: 7.5 m2/day (0.7 ft2/day)




5.1.2 Bedrock The bedrock underlying the site is mapped as sandstone associated with minor conglomerate belonging to the sedimentary Chilliwack Group Formation. Thermal properties for sandstones characteristic of the region are:


Thermal diffusivity: 7.5 to 10.8 m2/day (0.7 to 1.0 ft2/day) Bedrock formations typically have better heat exchange properties than unconsolidated soils due to their higher density. Note that bedrock can often be cost-effectively drilled for geoexchange purposes if the bedrock contact is at a relatively shallow depth (i.e. less than about 23 m bgs). When the bedrock contact is deeper than this, the transition from cased drilling techniques in the unconsolidated upper materials to open-hole rock drilling methods is often awkward and leads to higher GHX construction costs. Review of the water well logs (discussed in more detail in following section) indicates that Well A did not contact bedrock at a drill depth of 72 m (236 ft). Therefore, from this information we conclude that bedrock is unlikely to be encountered with typical GHX installations at this site. 5.1.3 Groundwater To satisfy a reasonable base-load portion of the Site C heating load a high capacity and sustained groundwater extraction of (greater than 380 L/min) would be required. Well depths and yield estimates reported on the Ministry of Environment database well logs identified within 500 m of the site are summarized below:

Well A 72 m (236 ft) 2,275 L/min (600 USgpm) (bedrock not encountered)

Well B 19 m (62 ft) no yield reported (bedrock not encountered)

Well C 23 m (76 ft) 1,140 L/min (300 USgpm) (bedrock not encountered)

Well D 12 m (38 ft) 190 L/min (50 USgpm) (bedrock not encountered) Notations in the Well A log indicate that iron and manganese were tested at different zones while drilling, and the reported results suggest that iron concentrations were about 2 ppm in samples tested at depths shallower than 48 m (160 ft), whereas they were undetectable in samples tested at depths below 48 m. Groundwater with iron concentrations at 2 ppm is generally not suited for geoexchange purposes, unless a rigorous maintenance and/or treatment program is maintained. The existing onsite water well providing water for the poultry barn does not appear in the water well database. However, since the existing water use at the facility is understood to be relatively minor (washing, cooling mist, and watering for the chickens), it is doubtful that the well was completed as a high capacity well with extended screen lengths and careful development. Furthermore, it is doubtful that the well was extended to the deeper aquifer zone that seems to have less dissolved iron than shallower groundwater. Therefore, it is believed doubtful that the existing well would be suited to provide a high capacity and high quality source for a geoexchange system. 5.1.4 Surface Water There are no suitable surface water bodies on or immediately adjacent to the site.



6.0 Geoexchange Options Appropriate sizing of a geoexchange system is required to balance installation costs versus annual energy savings. In commercial settings, geoexchange systems are often sized to serve only a base load portion of the heating capacity. Additional geoexchange capacity that would be required to handle rarely occurring peak loads often does not operate enough hours of the year to generate a meaningful return on investment. The duration of heating loads originally presented in Figure 1 are shown again in Figure 5 with the proposed heat pump capacity. Viewing the annual heating requirements in this way clearly illustrates that the poultry barns experience heating loads near the peak load for extremely short periods in a typical year. For feasibility analysis, we have selected a heat pump capacity of 56 nominal tons (i.e., 2 x 28 nominal ton units) rated to provide a delivered capacity of 124 kW (422 MBH) at mid-winter design conditions. The heat pump capacity is plotted on Figure 5 to depict met loads by geoexchange. Peak and annual load met by geoexchange heat pumps is summarized as follows:

Peak heating delivered by geoexchange: 124 kW (422 MBH) 18% of peak load

Annual heat delivered by geoexchange: 1,443 GJ (1,368 MBtu) 83% of annual load

Annual equivalent full load hours: 3,242 EFL hours

Figure 5. Duration of heating requirements as a percentage of peak heating load for Site C Poultry

Barn illustrating proposed heat pump capacity

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6.1 GHX Option Comparison

The available GHX options (vertical closed-loop, horizontal closed-loop, groundwater open-loop, and surface water open-loop) are evaluated in Table 1.

Table 1. Comparison of GHX Options at Site C Poultry Barn



H-GHX

Trenched horizontal

GHX (closed-loop)

High H-GHX systems can be very cost effective for certain ground conditions where low cost rapid trenching methods can install heat exchange (HX) pipe quickly and reliably. In many settings there is often insufficient space to install enough horizontal ground loop capacity to serve a meaningful portion of the peak loads. However, many agricultural sites, including this site, have relatively large available areas surrounding the heated facility.

The chain-trencher method is among the most cost-effective methods for H-GHX installation. Based on information gathered for shallow soils at the site, the chain trencher method is expected to be suited for the soils. This method excavates narrow trenches to a depth of about 1.8 m and two heat exchange pipes are placed at the bottom of each trench and then backfilled. The trenches are typically separated by 2.4 to 3.0 m centre-to-centre.

Approximately 2.43 ha of land area are available south of the barns, between the barns and the drainage that cuts diagonally across the site area as shown in Figure 3. Further capacity could be gained with additional trenching on the south side of the drainage, but crossing the drainage would add additional complexity to the GHX.

H-GHX Size Estimate To meet the proposed heat pump loads using the chain trencher method with assumed soil properties and 3.0 m trench spacing, a total trench length of approximately 5,800 m would be required (perhaps 48 circuits at 122 m per circuit). This would occupy an area of approximately 17,700 m2 accounting for the soil properties expected at this site.

Constructability The chain trencher method is expected to be suitable. If conditions do not allow chain trench methods then trenching by excavator could be considered as an alternative with somewhat higher associated costs.

Merits Lower cost than V-GHX option and more certainty of adequate performance and more certainty of construction cost than the GW-GHX option. Some of the cost could be internal if the Owner conducted the excavation work.

V-GHX


Low The vertical borehole option (V-GHX) is inherently the most versatile of all options because it requires much less land area than H-GHX options, and is less sensitive to site-specific conditions than open-loop groundwater. However, when other options are feasible, the V-GHX option is usually the most expensive of all options.





Water well logs indicate the presence of gravel layers at depths below about 6 m underlying the site. The presence of gravels would require the use of more expensive cased drill methods or heavy mud rotary drill equipment (to grind through gravel cobbles), to drill and maintain the boreholes. As a result, the cost for V-GHX drilling is expected to be a factor of 3 or more times greater than the cost for installing equivalent H-GHX heat exchange capacity.

GW-GHX


GHX (open-loop)

Moderate In areas with high groundwater production capabilities, GW-GHXs can often provide high rates of heat exchange at relatively low cost when compared with closed-loop options. The relatively constant temperature of deeper ground water sources can also lead to slightly higher GSHP efficiencies.

Review of water well logs for nearby wells suggests a high likelihood that high capacity groundwater production could be developed at the site. However, further review of the logs suggests the presence of iron in shallow groundwater zones (zones less than 49 m) at concentrations which often results in fouling of heat exchangers. Therefore, relatively deep (therefore more expensive) water wells may be required to provide adequate groundwater of suitable water chemistry.

From our experience, a GW-GHX system could likely be installed at a lower cost than an H-GHX system. However, the cost to install a pair of high-capacity wells (extraction well and a companion injection well), including thorough testing and pump/pipeline installation will approach the expected cost for H-GHX system for this site. Furthermore, the GW-GHX is subject to greater uncertainty regarding the level of performance to be expected and will be subject to higher ongoing maintenance requirements.

This application is somewhat small to take full advantage of the economies of scale that GW-GHX systems can often provide.

SW-GHX

Surface water GHX

(open-loop)

Low There are no suitable surface water bodies on or immediately adjacent to the site.

Based on information gathered to date, the most cost-effective GHX option regarding constructability and performance is the trenched horizontal closed-loop H-GHX option.





56 nominal tons of water-to-water heat pumps in increments of 28-ton modules served by a horizontal closed-loop trenched heat exchanger.

The current heating system doesn't require a heat distribution system, so there is no existing distribution system that the geoexchange system could connect with. Therefore, heat produced by the heat pumps would require a completely new system for heat distribution. We propose a hydronic (hot water) distribution system consisting of fan coil unit heaters alone or in combination with moveable hydronic rail piping that could be installed near the floor parallel to the existing feed and water distribution systems in the barns (to gain the benefit of heat introduced near floor level).

The hydronic distribution system would be designed to operate at delivery temperatures no higher than 50 °C to maintain efficient performance of the heat pumps.

The existing natural gas radiant heater system would be left intact exactly as is, so they could provide supplemental heating during short-term intense heating periods that are beyond the capacity of the geoexchange system, and so they could provide a completely redundant heating system in the event of maintenance of the geoexchange system.

Geoexchange heating capacity in the proposed configuration would satisfy approximately 18% of the peak heating load. This capacity would allow the geoexchange heat pump system to meet approximately 83% of the annual heating load.

Staging priority: 1. Geoexchange heat pumps

- Radiant rail system

- Hydronic Unit heaters 2. Natural gas radiant brooder heaters 3. Natural gas unit heaters

Geoexchange cooling could be provided in summer months by reversing the heat exchange cycle. However, in discussion with the Owner we understand that relatively little cooling is currently required and that the misting system typically provides sufficient cooling. We also understand that the Owner is considering evaporative cooling pads to improve the performance of the existing cooling system.





Trench method: Excavated trench (chain trencher or excavator method)


Trench to trench separation: 3 m

Heat exchange pipe: 25 mm (1-inch) nominal diameter SDR 11 HDPE

Heating Loads: As indicated - heating only operation


Minimum entering source temperature to heat pump: -2 to -1°C

Heat Pump COP: 3.2 at -1°C entering source temperature


Overall trench length: Approximately 5,800 m of trench

Area Required for GHX: 17,700 m2

TO / FROM HYDRONIC

UNIT HEATERS

TO / FROM REMOVEABLE

HYDRONIC RAIL HEATING AT

FEEDER LEVEL


48 CIRCUITS, 19,200 FT TOTAL HX PIPE.

HP-1 HP-2



6.3 Geoexchange Energy Analysis

The annual energy consumption for the proposed geoexchange system was calculated using the same DOE2 model as the base case calculations. Summary of geoexchange system performance expectations as compared to base case:

Natural gas annual consumption expected to decrease from 1,745 GJ to 267 GJ due to reduced reliance on the gas radiant brooder heaters. The resulting annual cost saving is $14,404.

Annual electrical consumption expected to increase from 80,944 kWh to 212,317 kWh per year to operate the heat pump system, resulting in an annual cost increase of $10,300 per year for electricity as compared to base case.

The net annual energy cost reduction is expected to be $4,104 at current utility rates.

GHG reductions amount to approximately 71 tonnes CO2e per year. 6.4 Geoexchange Options Cost Estimate

Preliminary additional cost estimates for the proposed geoexchange system beyond the base case costs are summarized in Table 2. Table 2 Estimated additional costs of proposed 56 nominal ton geoexchange system

Item Estimated Cost

Horizontal Ground Heat Exchanger $60,000 Heat Pumps $110,000 Heat Pump install and commissioning Addition of radiant rail and unit heaters

$28,000 $76,000

Controls $5,000 Engineering $29,000 Total $308,000


There are no specific technical challenges that would limit the installation of the proposed geoexchange system in this setting. The available land area is capable of providing ground heat exchange capacity for meeting the loads described in the conceptual design. The Owner would need to consider whether burial of piping in the proposed area would be compatible with long-range plans for the farm. 7.2 Financial Feasibility

The financial costs of the base case and geoexchange system scenarios for the poultry barn are summarized in Table 3. Under current conditions, the proposed geoexchange system has a Chabot Profitability Index4 (CPI) of -0.33 and an IRR of just 0.8%, and is therefore not considered financially viable.




Table 3. Financial Evaluation of Proposed Geoexchange System for Site C Poultry Barn


All else being equal, any of the following conditions would lead to financial viability at a CPI of 0.3:

a blended electrical rate of $ 0.042 / kWh,

a blended natural gas rate of $20.30 / GJ,


a capital grant of $170,700

Option Baseline Geoexchange to

meet 18% of

peak load

Weather file Abbotsford Abbotsford

Electricity Rate BCH 1151 Res BCH 1151 Res

Blended Electricity Cost ($/kWh) 0.079$ 0.079$

Natural Gas Rate FBC Rate2-2012 FBC Rate2-2012



Heat Pump Capacity (nominal tons) 56

Nominal Heat Pump Capacity (MBH @ 100° ELT, 30° EST) 422





Electricity Consumption (kWh) 80,944 212,317

Electricity Cost 6,402$ 16,702$

Natural Gas Consumption (GJ) 1,745 267



Propane Cost

Total Energy Consumption (Mbtu) 1,931 978

Total Energy Cost 23,704$ 19,601$

Energy Cost Savings 4,104$

Additional Capital Cost 308,000$

Project Internal Rate of Return 0.8%

Chabot Profitability Index -0.33

Annual GHG Emissions (tonnes CO2e) 89.8 18.7

Annual GHG Reduction (tonnes CO2e) 71.1 Potential Annual GHG Offset Value ($25/tonne CO2e) 1,776.96$




It is technically feasible to adapt geoexchange heating for the Site C Poultry Barn.

The horizontal trenched method of ground heat exchange appears most suited for this site, while there is evidence of moderate likelihood that a suitable groundwater open loop system could also be implemented. Other ground heat exchange options are not suited to the site setting.

A completely new heat distribution system would be required to convey heat to the barns. This is an added cost that some other geoexchange applications are not burdened with (i.e. in some cases the existing heat distribution system can be adapted to distribute geoexchange heat).

Although geoexchange application at this site would result in significant natural gas consumption reductions, the prevailing very low rates for natural gas (compared to considerably higher rates that have prevailed in the recent past) do not generate significant energy cost reductions. As a result, the business case for this application is considered unprofitable.

Although geoexchange for this application does not meet profitability criteria, the same application compared to a propane base case is profitable.

Application of geoexchange at this site would result in significant GHG reductions.

9.0 Recommended Next Steps The business case has been determined to be unprofitable for this application in this setting. Unless the Owner is motivated to proceed on the merits of GHG reductions alone, or for other reasons aside from satisfying the profitably target defined in this study, then no further action appears warranted at this time.

Appendix A Site D – Poultry processing facility

Altum Engineering Ltd. & JDQ Engineering Limited A95

Site D – Poultry Processing Facility

Contents 1.0 Executive Summary ......................................................................................................................... 96

2.0 Background ..................................................................................................................................... 96

3.0 Scope of Work ................................................................................................................................. 96


4.1 General Description ..................................................................................................................... 97

4.2 Current Heating and Cooling Systems ......................................................................................... 98


4.4 Base Case Energy Analysis ........................................................................................................... 99

4.5 Potential Energy Conservation Opportunities ........................................................................... 102

5.0 Site Characteristics ........................................................................................................................ 103

5.1 Subsurface Information ............................................................................................................. 103

6.0 Heat Recovery and Geoexchange Options ................................................................................... 106

6.1 Mechanical System Options Overview ...................................................................................... 106

6.2 GHX Option Comparison ........................................................................................................... 108

6.3 Proposed Conceptual Design ..................................................................................................... 110

6.4 Geoexchange Options Energy Analysis ..................................................................................... 112

6.5 Geoexchange and Heat Recovery Options Cost Estimates ....................................................... 112

7.0 Geoexchange Feasibility ............................................................................................................... 113

7.1 Technical Feasibility ................................................................................................................... 113

7.2 Financial Viability ....................................................................................................................... 113

7.3 Conditions Required for Feasibility ........................................................................................... 114

8.0 Conclusions ................................................................................................................................... 115

9.0 Recommended Next Steps ............................................................................................................ 115






1.0 Executive Summary Site D is a 706 m2 (7,600 ft2) poultry processing facility on Vancouver Island. The site is serviced by natural gas. Heat is currently provided by electric baseboards, a gas-fired make-up air unit for ventilation, and two gas-fired process hot water tanks. Cooling is currently provided by separate refrigeration units serving the blast cooler, processing (cut & pack) room, storage freezer, two storage coolers and shipping cooler. The two major energy loads of the facility are service water heating (SWH) and rapid refrigeration of carcasses in a blast cooler immediately after processing. The other heating and cooling systems in the facility did not have large enough energy loads to warrant including them in the proposed geoexchange retrofit. It is technically feasible to recover heat directly from the blast cooler equipment and transfer that heat to a SWH pre-heating system and to provide further SWH pre-heating with a geoexchange system. Of the various options available for ground heat exchange, a horizontal trenched approach is most suitable. A new direct heat recovery and 6.5 nominal ton geoexchange system would significantly reduce energy costs at the facility and is economically viable compared to the natural gas base case.













recommending next steps based on the feasibility assessment


Site D is a 706 m2 (7,600 ft2) poultry processing facility established in 2004 on Vancouver Island. The building is constructed with a mixture of wood framing (ancillary areas, building shell) and structurally insulated panels (processing and refrigerated areas). The single storey wood frame building has a finished attic space that is used for office, storage and lunch rooms. The exterior walls are typical 2x6 wood frame construction with R-20 insulation. The roof has R-40 insulation. Windows are clear double pane glass in aluminum frames. The refrigerated areas are supported by insulated slab on grade foundations with concrete foundation walls supporting the structurally insulated panels. The walls of the refrigerated areas are post and beam construction with structurally insulated R-30 panels on concrete foundation walls. The abattoir receives live birds and processes them into refrigerated or frozen meat for market year round, with production of up to approximately 4,700 birds/day. The processing includes packaging of whole birds and value-added “cut & pack” processing. The facility operates three days per week from January to May and five days per week from June to December. Processing occurs for 4 -5 hours in the morning, with packaging and cleaning following the processing. The end result of the processing is production of clean, safe (inspected) and professionally packaged poultry ready for market. The overall process consists of:

loading birds from cages onto a conveyor (hanging birds from their legs);

slaughtering of birds while still on the conveyor;

conveyance of birds through a hot water scald tank to sanitize and prepare them for plucking;

removal of feet from the carcasses, allowing the carcasses to drop into an automatic plucking machine;

plucking in an automatic plucking machine;

evisceration and further cleaning of carcasses using labour and machines;

blast cooling of carcasses; and

value-added processing (portioning, seasoning etc.), packaging and refrigerating or freezing product.

There are six cold rooms, each with separate, dedicated refrigeration using air-cooled condensing units. Room temperatures range from -18° C in the freezer to 10 °C in other cold rooms.



The facility is served by the FortisBC natural gas grid, the BC Hydro electrical grid, and a municipal water supply. The current electrical service is 600 A at 240 V. The electrical service may have sufficient spare capacity for additional loading from a heat pump, however, an electrical audit would be required to confirm this. A site visit to evaluate the structure, existing heating / cooling systems, and general site characteristics that may influence available GHX options was completed on January 13th 2012. 4.2 Current Heating and Cooling Systems

The current heating and cooling systems are as follows:

Electric baseboard heating serving office, lunch room, change room and other ancillary areas

A make-up air (MUA) heating and ventilation unit serving the evisceration room

A central service and domestic hot water (DHW/SWH) heating system serving the domestic hot water system (taps, sinks, showers), scald tank, evisceration equipment, and dishwasher. There is a separate heater for the hot water wash-down pressure washer

Various unitary refrigeration equipment dedicated to separately serving the blast cooler, processing (cut and pack) room, storage freezer, two storage coolers and shipping cooler

The majority of the existing heating and cooling equipment is the original equipment that was installed when the facility was constructed in 2004. 4.2.1 Electric Baseboard Heating Although electric baseboard heating is not an energy efficient method of providing space heating, it does provide accurate zone temperature control and is inexpensive to install. Since the zones that are served by electric baseboard heating are relatively small and are intermittently used, the amount of annual energy used for electric heating is not significant compared to the amount of energy used for processing. It is often prohibitively expensive to install a geoexchange system to replace an electric baseboard system serving many small spaces that are intermittently used. Therefore, the existing electric baseboard system was not considered in the analysis. If a geoexchange system is installed in the building, it could be used to replace the electric baseboard heating. However, the motivation for serving those zones with the geoexchange system would likely have to be non-financial since the replacement would require a new distribution system. That distribution system would consist of a hydronic (water-based) piping network or a forced air ducting network. Either option would be technically feasible but not likely financially viable. 4.2.2 Make-up Air Heating and Ventilation Unit Heating and ventilation is provided by a direct fired gas MUA unit providing 2,831 L/s (6,000 CFM) of fresh air with a discharge setpoint of 10 °C. This unit serves the evisceration and kill rooms. The MUA unit is interlocked with exhaust fans, which means it is turned on when the exhaust fans are turned on. The exhaust fans are turned on when the process starts and the MUA unit is then used to supply fresh air to the facility.



4.2.3 Service and Domestic Hot Water Heating System The existing service and domestic hot water heating system consists of two direct-fired natural gas fueled storage tanks, a gas-fired pressure washer water heating tank and an electric heater for the dishwasher. Hot water is provided for both process and domestic water uses from the two central 379 L direct-fired gas hot water tanks. Major SWH loads are the scald tank make-up water, scald tank heating coil, plucking process, evisceration process and dishwasher. The setpoint for the SWH tanks is 82 °C in order to maintain the appropriate scald tank temperature. The 3,028 L scald tank is filled with hot water at the beginning of each day and is kept at 60 °C by a heating coil in the scald tank. The heating coil has hot water circulated through it from the hot water tanks to keep the water in the scald tank warm using domestic hot water that is physically separated from the scald tank water by the coil (pipe). The heating coil in the scald tank requires a supply water temperature of approximately 82 °C in order to keep the scald tank at the setpoint temperature. Most other uses of hot water require the water temperature to be 60 °C or lower at the point of use. However, the applications that are served by the SWH storage tank system all require a minimum temperature of 60 °C for sanitation of the central SWH tank. The hot water pressure washer has its own dedicated gas water heater and pump. The supply water temperature setpoint is 79 °C. The pressure washer system is used intermittently throughout each day of operation and during hours when the rest of the facility is inactive. 4.2.4 Unitary Refrigeration Equipment The various unitary refrigeration units are similar to one another in form and function, with the only major variable being the size of a particular unit and the room temperature being maintained. The vapor compression refrigeration cycle is used to extract energy from the cold room or freezer spaces. The energy is then rejected from each of the chilled spaces via an outdoor condenser. With the exception of the blast cooler, each chilled space is served by a separate, dedicated refrigeration unit. The blast cooler is served by two completely independent refrigeration units for redundancy. This design is in place because the blast cooler is critical for food safety and would become a serious bottleneck in the process if it malfunctions. 4.3 Proposed Expansions or Renovations

Although no specific plans are in place to expand or renovate the facility at this time, the opportunity exists to increase the hours of operation within the existing facility as the business grows and heating and cooling loads may be expected to increase over time. However, the feasibility study is focused on adapting geoexchange technology to the current operation and only the existing heating and cooling requirements have been considered in the proposed geoexchange size and economic analyses. 4.4 Base Case Energy Analysis

The base case energy analysis corresponds to the current heating system serving the existing operation of the facility.



The peak heating demand and annual heating energy consumption were estimated for the facility hot water consumption, refrigeration, and MUA unit operation using DOE2 energy modeling software. Key modeling assumptions include:

Operation: Full year (12-month)

Weather file: Victoria, BC

Utility rates1: Electricity: BC Hydro 1500 MGS,

Natural Gas: FortisBC VI Large Commercial Rate 2

Building envelope: Mixture of wood frame and structurally insulated panels as described above

Building Heating: Electric baseboard heating

Ventilation Heating: Natural gas (processing area MUA unit)

SWH Heating: Natural gas (central SWH tanks)

Hot water loads:

o Scald tank: 3,028 L fill plus 307 L per hour make-up during processing

o Plucker/Evisceration: 2,271 L per hour during processing

o Pressure washer: 606 L per hour, 8am – midnight

o Dishwasher: 238 L per hour, 8 hrs/day, 3 days per week Without including the electric baseboard heating as described above, there are two major load profiles in the facility:

SWH / space heating, and

process cooling. The heating load profile is largely dominated by the SWH load; the MUA unit load is relatively insignificant in comparison. The total annual SWH load is approximately 1,704 GJ (1,616 MBtu) with a peak of 273 kW (934 MBH). In contrast, the annual energy consumption of the MUA unit is approximately 15.1 GJ (15 MBtu). This is a relatively small annual energy load at approximately 0.9% of the total natural gas energy consumption. The MUA unit was not given further consideration in the retrofit conceptual design due to the expected financial viability of retrofitting the existing equipment and the portion of the total heating load that is due to the device. However, if an entirely new MUA unit is required in the future and a geoexchange system is in place, replacement of the existing unit with one that is compatible with a heat pump based energy system may be viable. The duration of SWH system loads (presented as a percentage of the peak load) are presented in Figure 1. The plot shows how many hours in a year the heating system must operate at a given heating capacity. For example, it becomes clear from Figure 1 that 100% of the peak heating load is only required for very few hours each year (extreme left of the plot) but 10% of the peak heating load is




required for almost half of the year. This information is useful for analysis and design purposes because it describes both the intensity of the heating load and the cumulative duration of different heating intensities throughout a typical year. The SWH load profile has four distinct steps related to the various major processing loads, which operate according to a relatively consistent daily operating schedule. Section A of the curve represents the morning processing period when all major equipment is operating. Section B represents the early morning filling of the scald tank. Section C is in the afternoon when the pressure washer and dishwasher are running. Section D is in the evening when only the pressure washer is running. Due to the dishwasher running on off days in the first part of the year and due to other minor hot water loads, the loads steps are not quite flat. The plucker / evisceration process and pressure washer each account for approximately 40% of the load, while the scald tank accounts for approximately 15% of the load. The dishwasher and minor loads account for the remainder.

Figure 1. Duration of service water heating requirements as a percentage of peak heating load for

Site D Poultry Processing Facility

Monthly estimated SWH system requirements are illustrated in Figure 2. Whereas Figure 1 shows the cumulative duration of loads at increasing levels of heating intensity, Figure 2 shows a month-by-month account of heating demand through a typical year. Figure 2 also shows the potential waste rejected from the refrigeration equipment to illustrate the magnitude of potential heat recovery. Note that heat is required in all twelve months of the year for the process loads at this facility. The SHW and refrigeration heat rejection curves have a similar shape because both loads are dependent on the amount of processing done in a given month. Processing rates are higher from June to December leading to higher energy use in these seven months of the year.

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The annual refrigeration heat rejection is approximately 449 GJ (426 MBtu) with a peak of 80.8 kW (276 MBH). Approximately 44% of the annual refrigeration heat rejection (GJ) and 46% of the peak load (kW) are due to the blast coolers. The next largest load is due to the cut & pack cooler which contributes approximately 21% of the annual and 24% of the peak loads. Other equipment used for general space cooling make relatively small individual contributions to the annual and peak energy rejection loading.

Figure 2. Monthly service water heating and refrigeration heat rejection for Site D Poultry Processing

Facility

Annual energy consumption for the base-case scenario is estimated to be:


Natural gas: 2,227 GJ. Total annual GHG emissions are estimated to be 119 tonnes CO2e. 4.5 Potential Energy Conservation Opportunities

The following energy conservation opportunities were observed during the site visit:

The SWH system is maintained at 82 °C in order to heat the scald tank. All other requirements appear to be 60 °C or lower. A separate boiler plant could be used to heat the scald tank, and the DHW tanks could then be maintained at 60 °C. A separate boiler would allow domestic water heating to be separated from process water heating. This could not be justified on energy savings alone, but might be considered on the basis of providing additional capacity, or as part of a DHW plant upgrade/replacement.

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The concrete footings in the cold rooms are not insulated, resulting in substantial heat gain compared to the rest of the wall. These should be insulated where possible.

Installation of programmable thermostats would be a viable near-term energy efficiency option for the electric baseboard system. The thermostats would automatically adjust the zone temperatures to lower set-back values during times when the spaces are not in use.

5.0 Site Characteristics The site is level and relatively open with an adjacent field that has an approximate area of 0.8 ha. The entire site is approximately 2.8 ha. There is a stand of relatively large trees on much of the site but the field is within a reasonable proximity to the facility. Figure 3 shows the general layout of the site. Following the routing that interconnecting pipes would take between the mechanical room and the field, the field is located approximately 50 m from the existing mechanical room. Therefore, there is ample room nearby for installation of virtually any feasible type of ground heat exchanger (GHX).

Figure 3. General Site Layout



Bedrock Geology: Duncan Sheet, Vancouver Island, Map 42A, British Columbia, Geological Survey of Canada, 1918.

Surficial Geology: Capilano Sediments (sand, gravel, silt and clay) and Vashon Drift (gravel, sand and till), Victoria Map Area, Vancouver Island and Gulf Islands, British Columbia, Open File 701.

Lithology descriptions from water well drill logs for the 20 nearest water wells to the site accessed from the BC Water Atlas, with a focus on any wells reported to be capable of producing over 38 L/min.

Previous direct observations of drilling conditions, reported by a local water well driller to the Owner.

PROCESSINGFACILITY

ADJACENTFIELD

20m



Thermal conductivity and diffusivity values (key properties of soils and/or bedrock that govern how heat transfers through soil/bedrock) for shallow and deeper soils have been estimated with reference to Soil and Rock Classification for the Design of Ground-Coupled Heat Pump Systems, Electric Power Research Institute, 1989, and Ground-Source Heat Pumps; Design of Geothermal Systems for Commercial and Institutional Buildings, Kavanaugh and Rafferty, ASHRAE, 1997, and by direct professional experience.

Based on available climatic data for the region and our previous ground testing experience in the South Coast region the expected deep ground temperature at the site is approximately 11.7 °C. 5.1.1 Upper Soils There were no significant road cuts or other features near the site that could be used to confirm verbal and reported information regarding the nature of the upper soils in the direct vicinity of the facility. However, the Owner is involved in local agriculture and has knowledge of the site ground conditions. He reported that the upper soils on the site are expected to be granular (i.e., sands and silts) to a depth of approximately 15m BGS. Below that level, there is likely a blue clay layer sitting on top of gravels. The review of nearby well logs confirmed the expected conditions reported by the Owner, with a probability of clay near the surface. The lithology appears to be a glacial outwash deposit, based on the reviews of available data. Shallow soils at the site (between a depth of 1.2 to 2.1 m relevant for analysis of horizontal GHX systems) are expected to consist primarily of deposits of gravels, sands, clay and silt. The water table is expected to be very far below the surface, which would mean that the ground materials that a GHX would be constructed in would be relatively dry. Therefore, it was assumed that unsaturated conditions would be dominant for a large portion of the year and the analysis was conducted with the following estimated thermal properties:

Thermal conductivity2: 0.87 to 1.4 W/m-K (0.5 to 0.8 Btu/hr-ft-°F)

Thermal diffusivity3: 0.056 m2/day (0.6 ft2/day) 5.1.2 Bedrock The bedrock underlying the site is mapped as part of the Nanaimo Group Formation, which consists of sedimentary rock such as sandstone and shale with coal layers. Observations recorded in the well logs indicate that shale is the most prevalent rock type in the uppermost bedrock near this location. This type of rock can be drilled economically in the right situation (i.e., if the bedrock contact is close to the surface). Bedrock formations typically have better heat exchange properties than unconsolidated soils due to their higher density. Note that bedrock can often be cost-effectively drilled for geoexchange purposes if the bedrock contact is at a relatively shallow depth (i.e., less than about 25m BGS). When the bedrock contact is deeper than this, the transition from cased drilling techniques in the unconsolidated upper materials to open-hole rock drilling methods is often awkward and leads to higher GHX construction costs.




Thermal properties for the expected type of bedrock are:


Thermal diffusivity: 0.084 to 0.10 m2/day (0.9 to 1.1 ft2/day) The well logs from near the site indicate that bedrock contact is expected to occur at a depth in the range of 87 to 114 m BGS. Therefore, the bedrock geology is relatively insignificant for the purposes of the analysis since drilling of a vertical GHX would likely terminate in the overburden rather than in the bedrock. 5.1.3 Groundwater The heating and cooling loads are significant enough to warrant the consideration of an open-loop system, but only if an exceptional source of acceptable groundwater were readily available close to surface. Without ideal groundwater conditions, the magnitude of the annual energy and peak loading would not warrant consideration of an open-loop option. The Owner of the facility has reportedly investigated the feasibility of installing a water supply well on the site. He consulted with an experienced local water well driller with direct local experience. He apparently indicated that the facility is located in a local area of relatively poor groundwater production potential (though the local area is surrounded by a larger region with generally good groundwater production potential. Review of the Ministry of Environment water well database (accessible through the BC Water Atlas) confirms the information provided by the local driller. The depth to water and productivity of the wells listed in the well logs that were reviewed indicate that a sufficient source of groundwater is not likely available at the site. Deep static water levels in the range of 55 m (180 ft) to 73 m (240 ft) BGS were reported in the reviewed logs. The four closest wells to the site were reported to produce less than 23 L/min (6 USgpm) and many other wells in the region had lower than 11 L/min (3 USgpm) of reported capacity. In addition to the depth to water and reported productivity of the aquifer, the thickness appears to be quite thin, on the order of 3.0 m to 4.6 m. Therefore, extracting water to serve a heat pump would most likely require re-injection of the water back into the aquifer to avoid dewatering it. The open-loop groundwater option is not expected to be feasible or viable for this site for the following reasons:

Significant depth BGS to water

Expected productivity of a reasonably sized / priced well

Likely requirement for at least one relatively costly injection well

Amount of pumping power that would be consumed to bring the water to the heat pump If a nearby source of groundwater could be shared with the facility, the open loop option may be feasible and viable. However, this option would increase the complexity for the Owner since there would have to be an agreement for the use of the water and an injection well would likely still be required.



5.1.4 Surface Water There is no surface water body on or adjacent to the site. However, the Owner expressed interest in constructing a pond in the field that is adjacent to the facility. Constructing an appropriate pond would likely be more expensive than constructing a horizontal GHX, although the pond option may be favourable compared to the other options if a pond is required or desired for other purposes.

6.0 Heat Recovery and Geoexchange Options Appropriate sizing of a geoexchange system is required to balance installation costs versus annual energy savings. In commercial settings, geoexchange systems are often sized to serve only a portion of the peak loads. Additional geoexchange capacity installed to handle the rarely occurring peak loads often does not operate enough hours of the year to generate a return on investment. The duration of heating loads originally presented in Figure 1 are shown again in Figure 4 with the proposed heat pump capacity. Viewing the annual heating requirements in this way clearly illustrates that the service water system only experiences heating loads near the peak load for very short durations of the year. Figure 4 shows both the total SWH load (light green) and the SWH load that would remain after heat recovered from the refrigeration systems is transferred to the SWH pre-heat system. For this facility a geoexchange system sized to meet approximately 6% of the peak load or roughly 21 kW (73 MBH) is recommended.

Figure 4. Duration of heating requirements as a percentage of peak heating load for Site D Poultry

Processing Facility illustrating proposed heat pump capacity

6.1 Mechanical System Options Overview

When considering an energy retrofit project, the first loads to consider are those that are the largest and can be reduced utilizing a single, central solution. This methodology often leads to an acceptable simple

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payback period (a lower capital cost to energy savings ratio). Most viable solutions are found where large quantities of energy consumption can be eliminated by adding a minimal amount of new equipment. As shown in the base case energy results presented above, the SWH load is the largest in this facility. This load could be reduced using a single, central solution with minimal addition of new equipment. Due to the magnitude of the loads associated with the blast cooler, SWH, and pressure washer systems, these loads are the most viable targets for energy use reduction in this facility. 6.1.1 Heat Recovery System Economically harnessing waste energy from one process and supplying it to another can be a viable target for an energy efficiency retrofit. If the processes occur at the same time, this can be accomplished without the use of thermal storage. If they occur at different times, such as daytime cooling and overnight heating, geoexchange is often a viable method for storing energy. Since the SWH consumption is the dominant load compared to the refrigeration heat rejection, the facility has a heating dominant load profile. In order to decrease the heating dominance of the SWH system and thereby decrease the size requirement of the GHX, recovering waste energy from the blast cooler refrigeration systems was considered first. Directly transferring waste energy from the blast cooler into the SWH system could increase the efficiency of the blast cooler option while providing very inexpensive energy to the SWH. Since these two processes operate on similar schedules and the SWH load is much larger than the blast cooling load there would be few occurrences, if any, when the blast cooler has excess energy to reject and the SWH system cannot absorb it. 6.1.2 Geoexchange for Heating Loads After reducing the SWH load using direct heat recovery from the blast cooler system, the remaining facility energy load would still be heating dominant. This means that there would be a requirement for a high capacity and relatively high cost GHX (per nominal ton of heat pump) to maintain a high enough GHX temperature and thereby maintain high efficiency operation of the heat pump(s) serving the SWH system. Assuming that a heat pump can output approximately 2.9 kW per nominal ton, a geoexchange system configured to serve the entire SWH heating load would be approximately 94 nominal tons. That is a relatively large system compared to the annual energy consumption, particularly after the SWH load has been reduced by heat recovery from the blast cooler. Therefore, a geoexchange system serving a much smaller portion of the peak SWH load would be more appropriate from a financial viability perspective. 6.1.3 Geoexchange for Cooling Loads If the entire cooling load was served by a single, central refrigeration system, it would lend itself well to a facility-wide refrigeration heat recovery system. Geoexchange could then be used to absorb excess energy when the SWH load is not significant enough to absorb all of the heat of rejection. Unfortunately, it would be costly to implement a central refrigeration heat recovery system since the refrigeration is achieved with many smaller packaged refrigeration units that are distributed throughout the facility. Retrofitting each of the existing packaged refrigeration units would be relatively complex and expensive. In addition to the complexity and cost, any problems with the system connecting the multiple refrigeration units would cause operational issues for the entire facility.



The blast cooler heat recovery was considered due to the magnitude of the energy rejected from that process and the relative simplicity of retrofitting one or both of the larger refrigeration units serving the blast cooler. Other major refrigeration loads such as the cut & pack cooler could be considered if the blast cooler retrofit is successfully completed. 6.2 GHX Option Comparison

The available GHX options (vertical closed-loop, horizontal closed-loop, groundwater open-loop, and surface water open-loop) are evaluated in Table 1. Table 1. Comparison of GHX Options at Site D Poultry Processing Facility



H-GHX

Trenched horizontal

GHX (closed-loop)

High H-GHX systems can be very cost effective for certain ground conditions where low cost rapid trenching systems can install heat exchange (HX) pipe quickly and reliably. In many settings there is often insufficient space to install enough horizontal ground loop capacity to serve a meaningful portion of the peak loads. However, this site has approximately 0.8 ha in near proximity to the building that are potentially available for H-GHX construction.

Care must be taken in designing and installing an H-GHX in the types of granular soils expected at this site. Granular materials by nature have limited areas of contact between one particle and the next and with the HX piping. Dry granular soils can therefore have very low heat transfer abilities and require considerably more HX piping to provide the equivalent heat exchange capacity as an H-GHX installed in saturated granular soils or other higher conductivity materials. Because of the expected low ground water table, it is safest to assume the H-GHX will experience dry conditions and to design accordingly.

H-GHX Size Estimate The proposed geoexchange system would require an H-GHX area of approximately 2,197 m2 to meet the capacity and annual heating parameters described above or about 27% of the available area.

Constructability The upper soil layer may allow for low cost methods such as the chain trencher method to be effective at this site. However, excavated trenching would be more certain to be suitable and is considered to be the leading option for installing an H-GHX on this site.

Possible Configuration The layout of the GHX would depend largely on the future plans of the Owner. As a site plan is currently under development, the exact configuration of the GHX would be determined at a later date.

Merits Overall cost is expected to be much lower than vertical drilling option and some of the cost could be internal if the owner conducted the excavation





work.

SW-GHX

Surface water GHX

(closed-loop, constructed

pond)

Moderate The potential plan for the Owner to install a pond on the site could lead to this option being favorable. This would only be the case if the pond is required for other uses or if the fill from the pond excavation is useful elsewhere on the site.

The cost of an SW-GHX in this setting would likely be increased by the cost of a clay or plastic liner in the bottom of the pond to keep water from draining into the soils. This possibility could be assessed if test pits were dug on the site to confirm the permeability of the near surface soils.

This option could lead to higher heating efficiencies than an H-GHX since the water in the pond would be exposed to relatively mild outdoor temperatures in this climate, which would re-heat the pond during the wintertime.

This option is considered moderately suitable due to the expected cost of construction.

V-GHX


Low The vertical borehole option (V-GHX) is inherently the most versatile of all options because it requires much less land area than horizontal options (H-GHX), and is less sensitive to site specific conditions than open-loop groundwater. However, when other options are feasible, the V-GHX option is usually the most expensive.

Predicted depths to bedrock and loose unconsolidated overburden suggest a cased drilling method is likely required for this site. While construction of a vertical borehole GHX is achievable in this setting, it is likely to be far more expensive than other options at the site (by a factor of 2 to 3 times greater than the H-GHX option).

GW-GHX


GHX (open-loop)

Low In areas with high groundwater production capabilities, GW-GHXs can often provide high capacity GHX at relatively low cost when compared with closed-loop options. The relatively constant temperature of deeper ground water sources can also lead to slightly higher GSHP efficiencies. However, the relatively fixed costs associated with water well drilling, development and testing usually makes GW-GHXs relatively more expensive for smaller geoexchange systems.

The hydrogeological review suggests a poor likelihood that adequate groundwater production could be cost effectively achieved at this site. Based on this, no further consideration of this option is warranted.

Based on information gathered to date, the most cost-effective GHX option regarding constructability and performance at this site is the horizontal closed-loop H-GHX option.




The proposed geoexchange system has the following key features:

6.5 nominal tons of water-to-water heat pumps serving the SWH system coupled to a horizontal closed-loop GHX as illustrated in Figure 5.

Geoexchange heating capacity of 21 kW (73 MBH) (6% of the peak SWH heating system load) at design conditions

Annual geoexchange heating contribution of 11% of the total annual SWH heating system requirements

Heat recovery heating capacity of 82 kW (280 MBH) (30% of the peak SWH heating system load) at design conditions

Annual heat recovery heating contribution of 24% of the total annual SWH heating system requirements

Base case (existing) fossil fuel SWH heating capacity and distribution system retained to meet peak SWH loads

The energy retrofit could be separated into three phases:

1. Recovering heat from the blast cooler system and using it to preheat water for the SWH system

2. Installing a GHX system to preheat water for the SWH system

3. Recovering energy from the cut & pack cooler and using it to preheat SWH if the cost of the retrofit is in line with the energy savings and consider recovering energy from other cooling processes as appropriate

The conceptual design schematic incorporating the first two phases is shown in Figure 5.

Figure 5. Conceptual Schematic

The blast cooler currently rejects energy to the air through its condensers. In order to transfer that rejected energy to the SWH system, these condensers would be coupled with parallel condensers that use water as the heat rejection medium when SWH heating is required and air as the heat rejection medium when SWH heating is not required. Water would be circulated through the condensers and into the pre-heat storage tank.

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The pre-heat storage tank would store water at a lower temperature than the gas-fired storage tanks, which require a minimum temperature of 60 °C for sanitation as described above. Heat pumps are easily capable of increasing the temperature of incoming cold water from the mains temperature of approximately 10 °C up to approximately 43 °C. Recovering energy from the existing refrigeration systems (with the exception of the freezer) can also preheat the SWH to approximately 43 °C or higher. The pre-heat storage tank would have a temperature sensor in the bottom of the tank to sense when cold incoming water from the mains enters the tank. The control system would then start the heat pump, the GHX pump and the heating pump to provide heating to the SWH pre-heat tank. If the blast coolers are operating at the same time, the heat recovery pump would be turned on and energy would be collected from the blast cooler refrigeration condensers. Since the SWH flow rate would be significant during most of the operating periods, the pre-heat storage tank would have relatively low temperature water in it. This would lead to high efficiency operation of both the heat pump and the heat recovery condenser. However, it would also lead to a requirement for the storage tank to be periodically heated to a sanitizing temperature of 60 °C. The high efficiency heating could be achieved via the heat pump and heat recovery system for most of the day. At the end of the day when the preheat tank reaches 43 C after the SWH load stops, the tank could be raised to a sanitizing temperature using an electric element or by circulating hot water from the gas-fired storage tanks. The following day would start with three sanitized tanks full of hot water at the setpoint temperature. The scald tank heating coil would be heated by a separate, new boiler to eliminate the requirement for the hot water tanks to be heated to 82 °C. This would save energy due to heat loss from the storage tanks while increasing the heating efficiency of the natural gas burners inside the tanks. The additional equipment required for the proposed system would take up some space in the facility. In order for the proposed system to be financially attractive, existing interior spaces or an inexpensive expansion to house the new equipment would be required. Right-Suite® Universal Version 8.0.16 (Wrightsoft Corporation, Lexington, MA) and/or Ground Loop Design GLD 2009 (Thermal Dynamics, Maple Plain, MN) computation software were used for integrating information about the ground conditions, GHX configuration, and heating/cooling loads to calculate the required GHX size and capacity. The proposed GHX configuration and design parameters are:

Trench method: Trenched by excavator

Trench depth (below surface): 1.5 m

Number of trenches: 8

Trench length and spacing: 85.3 m trenches, 3.0 m spacing

Pipe to pipe separation: 0.6 m


Piping circuit length: 171 m

Area Required for GHX: 2,197 m2



Antifreeze solution: 20% propylene glycol, by volume

GHX fluid flow: 10.6 L/m per nominal heat pump ton

Ground thermal properties: As indicated in previous section for shallow soils

Min Heat pump EWT: -1 °C

Heat pump heating COP: 3.1 at -1 °C EWT

Heat pump heating capacity: 15.2 kW (52,000 Btu/h) at minimum EWT

Heating only heat pump operation 6.4 Geoexchange Options Energy Analysis

DOE2 modeling analysis of the energy use schedule for the SWH system and the energy availability schedule of the blast cooler heat recovery system showed that implementing a small geoexchange system serving 6% to 9% of peak SWH load could be viable. When larger heat pump systems were considered, the simple payback period increased beyond a reasonable period. In fact, the shortest simple payback is forecasted for the heat recovery system only. Therefore, the geoexchange system serving 9% of the peak SWH was dismissed as an option, even though it would save more annual energy than the 6% of peak option. It is worthy of mention that, even though the simple payback period increased with larger heat pump sizes, the internal rate of return was still reasonable for the 9% option (approximately 15% internal rate of return). Therefore, the geoexchange system size could be economically viable if serving larger than 6% of the peak. The decision to increase the size of the system would depend on factors such as cash flow availability, financing / incentives and the rate of return that alternative investments would have. The 6% of peak option was chosen based on that option having the highest calculated internal rate of return and lowest simple payback period. The annual energy consumption and heating provided by the proposed 6% of peak (6.5 nominal ton) geoexchange system were calculated using the same DOE2 model as the base case calculations. The proposed geoexchange system and heat recovery system combination is expected to:

increase electrical consumption by 21,285 kWh/year;

reduce natural gas consumption by 754 GJ/year; and

reduce GHG emissions by 37.4 tonnes CO2e per year. The third phase of the retrofit was not considered in the energy analysis since the outcome of the first phase would prove if recovering the energy from the smaller refrigeration load of the cut & pack cooler would be worthwhile. 6.5 Geoexchange and Heat Recovery Options Cost Estimates

Preliminary cost estimates for the proposed heat recovery and geoexchange system options beyond the base case costs are summarized in Tables 2 and 3 below.



Table 2. Estimated Additional Costs of Proposed Heat Recovery System

Item Estimated Cost

Condenser Installation $5,000 Piping and Pump to Blast Cooler $3,000 Pre-heat Storage Tank $2,000 Controls* $2,000 Engineering $3,000 Total $15,000 * Controls includes all necessary controls for heat recovery system and heat pump system (Phases 1 & 2).

Table 3. Estimated Total Additional Costs of Proposed Geoexchange and Heat Recovery Systems

Item Estimated Cost

Horizontal Ground Heat Exchanger $7,800 Heat Pumps (6.5 nominal tons)* $16,250 Engineering $4,810 Heat Recovery System (from above)

$15,000

Total $43,860 * Includes all necessary components and installation (i.e., includes pumps, piping).


The proposed system would be simple and straightforward to design and install. The heat recovery retrofit of the blast cooler system would be the only technically challenging portion of the project. This is due to the fact that the blast cooler is a mission critical device and the retrofit would involve modification of a pre-engineered, packaged refrigeration system. However, with the right design and installation team, the retrofit would be technically feasible. The remainder of the system is comprised of standard components used as intended by the manufacturers of the equipment. The horizontal GHX option can be technically challenging in certain conditions such as a site with a high groundwater table, unstable soils and/or close proximity to a sensitive ecosystem. This site is not expected to be technically challenging due to the low water table and expected soil types. 7.2 Financial Viability

The financial costs of the base case and geoexchange system scenarios for the existing operations are summarized in Table 4. Under current conditions the proposed combined heat recovery and geoexchange system is considered financially viable with a Chabot Profitability Index4 (CPI) of 1.68 and an IRR of 26.7% when compared to the base case.




Table 4. Financial Evaluation of Proposed Geoexchange System


The proposed heat recovery and geoexchange system is financially viable under current conditions when compared to the base case.

Option Baseline Refrigeration

Heat Recovery

Only

Refrigeration

Heat Recovery +

Geoexchange to

meet 6% of peak

load

Weather file Victoria Victoria Victoria

Electricity Rate BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS

Blended Electricity Cost ($/kWh) 0.088$ 0.088$ 0.087$

Natural Gas Rate FBC VI Rate2 FBC VI Rate1 FBC VI Rate1

Blended Natural Gas Cost ($/GJ) 14.33$ 15.27$ 15.34$


Heat Pump Capacity (nominal tons) 6.5

Heat Pump Capacity (MBH @ 100° ELT, 30° EST) 52





Load met by Heat Recovery (Mbtu) 387 386

% total load met by Heat Recovery 24% 24%

Peak load met by Heat Recovery (MBH) 280 280

Electricity Consumption (kWh) 276,982 287,864 298,267

Electricity Cost 24,463$ 25,202$ 25,859$

Natural Gas Consumption (GJ) 2,227 1,705 1,473

Natural Gas Cost 31,912$ 26,034$ 22,592$


Propane Cost

Total Energy Consumption (Mbtu) 3,057 2,599 2,414

Total Energy Cost 56,374$ 51,236$ 48,451$

Energy Cost Savings 5,138$ 7,923$


Project Internal Rate of Return 45.9% 26.7%

Chabot Profitability Index 3.58 1.68

Annual GHG Emissions (tonnes CO2e) 119.0 92.9 81.5

Annual GHG Reduction (tonnes CO2e) 26.0 37.4 Potential Annual GHG Offset Value ($25/tonne CO2e) 650.39$ 935.46$



8.0 Conclusions A relatively low cost heat recovery and geoexchange system is technically feasible at this site. The economic benefits of the proposed system are dependable based on the known consistent SWH and refrigeration loads. The proposed heat recovery and geoexchange system would serve the SWH while recovering energy from the refrigeration system serving the blast cooler. These are the two major loads of the facility. The most attractive sized geoexchange system would have a nominal capacity of 6.5 nominal tons. Based on the energy modeling conducted in this study, the proposed system would reduce natural gas consumption by 754 GJ/year, reduce GHG emissions by 37.4 tonnes CO2e per year and increase electrical consumption by 21,285 kWh/year. If the facility were to increase production, the natural gas savings, GHG emissions reductions and electrical consumption would increase. The proposed system would have an annual energy cost savings of approximately $7,930/year. If the size of the geoexchange portion of the system were increased, the annual energy savings would also increase, but the simple payback period would be expected to increase and the internal rate of return would be expected to decrease. However, the internal rate of return for a larger geoexchange system was still in the 12% range, which may be attractive depending on the facility finances. The proposed system could be phased into three separate portions:

1. Heat Recovery Installation (Blast Cooler)

2. Geoexchange System Installation

3. Heat Recovery Installation (Cut & Pack Cooler) The first two phases are expected to be technically feasible and economically viable, while the third phase would have to be investigated further based on the outcome of the first phase. The geoexchange portion of the system could be served by a horizontal closed-loop GHX, a closed-loop pond GHX or a water service from offsite (if available). The horizontal closed-loop GHX is expected to be the leading option, but the preference of the Owner would have a strong influence on the final design.

9.0 Recommended Next Steps Based on the above conclusions and findings of the study, we recommended the following next steps:

Gather budget pricing of the proposed system from a qualified refrigeration mechanic prior to engaging a professional engineer for detailed design.

Seek renewable energy funding that has terms that enable the project to go forward without affecting the cash flow of the business.

If the budget pricing is acceptable and funds are available, develop a design for the proposed heat recovery system and gather quotes for the installation from qualified refrigeration mechanics.

Conduct an appropriate electrical load audit to determine if a heat pump can be installed without increasing the electrical service size. If the electrical service must be upgraded,



determine if the upgrade cost would be considered part of the long term growth strategy or part of the geoexchange system cost.

Decide whether or not a pond is required for other uses in addition to the contemplated geoexchange system. If the pond is a desirable option, develop a design for the pond GHX option.

If the pond option is dismissed, develop a design for the horizontal GHX option.

Gather quotes for the heat pump and GHX installation from qualified geoexchange practitioners.

Develop a financial plan that includes the proposed phasing and determine which phases to implement and at what time.

If the financial case for the project is strong, proceed with procurement and construction of the system.

Appendix A Site E – Aquaponics facility


Site E – Aquaponics Facility

Table of Contents 1.0 Executive Summary ....................................................................................................................... 118

2.0 Background ................................................................................................................................... 118

3.0 Scope of Work ............................................................................................................................... 118

4.0 Existing Operation ......................................................................................................................... 119

4.1 General Description .................................................................................................................. 119

4.2 Current Heating and Cooling Systems ...................................................................................... 120

4.3 Proposed Expansions or Renovations ....................................................................................... 122

4.4 Base Case Energy Analysis ........................................................................................................ 122

4.5 Potential Energy Conservation Opportunities .......................................................................... 124

5.0 Site Characteristics ........................................................................................................................ 125

5.1 Subsurface Information ............................................................................................................ 126

6.0 Geoexchange Options ................................................................................................................... 128

6.1 GHX Option Comparison ........................................................................................................... 129

6.2 Proposed Conceptual Geoexchange Design ............................................................................. 132

6.3 Ground Thermal Mass Storage for Seasonal Solar Storage ...................................................... 134

6.4 Energy Analysis ......................................................................................................................... 139

6.5 Geoexchange and Below-ground Thermal Store Cost Estimates ............................................. 139

7.0 Geoexchange Feasibility ............................................................................................................... 141

7.1 Technical Feasibility .................................................................................................................. 141

7.2 Financial Feasibility ................................................................................................................... 141

7.3 Conditions Required for Feasibility ........................................................................................... 142

8.0 Conclusions ................................................................................................................................... 142

9.0 Recommended Next Steps ............................................................................................................ 143






1.0 Executive Summary Site E is an aquaponics operation near Prince George, BC. The existing operation is housed in a 270 m2 (2,900 ft2) poly-covered greenhouse. Aquaponics is a food-producing method that combines aquaculture with hydroponics. In this case the aquaculture part of the system consists of six 8,000 L tanks that are used to raise tilapia fish and the hydroponic part of the system consists of 12 growing beds that produce herbs and vegetables. The facility is currently heated by a rooftop solar thermal system in combination with wood biomass boilers. The study examined the technical feasibility and economic viability for developing two distinctly different types of geoexchange energy system improvements for the facility, including:

Developing a typical geoexchange system for facility heating that would operate in combination with the existing solar and wood biomass boilers, and

Developing a below-ground thermal energy store for capturing excess summer solar heat produced by the rooftop solar thermal system and shifting some of the excess supply so that it can be used for gainful benefit in autumn and winter seasons.

The latter of these options was examined at the specific request of the Site Owner. It is technically feasible to adapt a typical geoexchange system for the Site E Aquaponics Facility. Of the various options available for ground heat exchange, a horizontal trenched approach is most suitable. However, while technically feasible, the development of a typical geoexchange system for this application in this site setting does not meet the profitability criteria established for the study nor would GHG emission reductions occur. The principal reason is the wood biomass base-case scenario provides low cost heat with neutral GHG emissions. It is also technically feasible to develop a below-ground thermal store to capture and preserve some of the solar heat that is currently wasted. However, there are technical constraints that cause the amount of heat that can be gainfully preserved to be relatively small. Consequently, the development of a below-ground thermal store does not meet the profitability criteria established for the study nor would GHG emission reductions occur.

2.0 Background This feasibility study was completed as part of a larger geoexchange benchmarking study conducted on behalf of the BC Ministry of Agriculture. This report should be read in conjunction with the Geoexchange Feasibility in Agricultural and Agri-Food Operations Benchmark Study to provide relevant context and background. The Benchmark report includes an overview of geoexchange technology and the results of geoexchange feasibility studies at several other agricultural facilities.












recommending next steps based on the feasibility assessment In addition, by specific request of the Site Owner, the scope for this site also included an analysis to evaluate below-ground thermal mass storage to provide a seasonal store for capturing and shifting excess summer solar heat produced from an existing solar water heating system.


Site E is an aquaponics facility located near Prince George, BC. The existing operation is housed in a 270 m2 (2,900 ft2) soft poly-covered greenhouse. Aquaponics is a food-producing method that combines aquaculture with hydroponics. In this case the aquaculture part of the system consists of six 8,000 L tanks that are used to raise tilapia fish and the hydroponic part of the system consists of 12 growing beds that produce herbs and vegetables. Nutrient-rich water is circulated from the tilapia tanks to the hydroponic growing beds where the nutrients nourish the herb/vegetable production. The uptake of the nutrients by the herbs/vegetables in turn cleanses the water before the water is circulated back to tilapia tanks. The system is essentially a closed-loop configuration. The only routine losses from the system are occasional removal of a small amount of filtered solids and evaporative loss of water from the open tanks. The only routine inputs to the system are fish feed pellets and minor make-up water to replace evaporative losses. Construction of the facility occurred in 2010, so it has completed just one full year of operation. The system is intended for year-round operation. At the time of the site visit in December 2011 only three of the six fish tanks were in operation.



The greenhouse has double-layer poly for the south and west walls. The east wall adjoins an unheated wood frame structure used for storage and the heating plant, and the north wall is metal with 3-inch continuous insulation. A double poly ceiling (energy curtain) is used in winter.

The fish tanks are maintained at 22°C. The ideal air temperature in the area of the hydroponic growing

beds is 18°C.

The site region is sparsely populated and not serviced with natural gas. We are not aware of future plans for gas service to be introduced to the area. Electrical service is provided by BC Hydro. Water is supplied by an onsite water well. A site visit was conducted on December 13th 2011 to meet the Owners and view the operation, including observations of:

the aquaponic production system;

greenhouse structure that the facility is housed within;

existing heating/cooling systems;

general site characteristics affecting suitability of ground heat exchanger (GHX) options; and

site attributes that may affect ground thermal mass storage for solar energy. 4.2 Current Heating and Cooling Systems

The current heating system consists of wood biomass boilers and solar hot water panels. The boiler system includes a 40 kW manual-controlled wood gasification boiler and an 80 kW automated boiler. At the time of the site visit only the 40 kW boiler was operational and the 80 kW boiler was being added to provide additional heating capacity. The boilers will be controlled so they operate as one or the other (not together). The 40 kW boiler is compatible with cordwood, while the 80 kW boiler is intended for wood chips or shavings. The boiler system produces hot water at a temperature of approximately 75 °C that is fed to an 8,000 L partly buried but otherwise un-insulated thermal mass tank. The solar system consists of an 800 ft² glazed solar panel array positioned on the roof of a wood-frame structure that adjoins the greenhouse. The panel faces south and is sloped at 45 degrees. An additional 400 ft² unglazed metal solar panel is mounted vertically on the north wall (facing south) inside the greenhouse and runs the entire length of the north wall (the panel is 4 ft high by 100 ft long). During sunshine periods, this panel absorbs and transfers heat from the greenhouse when the greenhouse is warmer than desired. Hot water from both solar panel arrays is directed to the same thermal mass tank as the boilers. Maximum summer tank temperatures produced by the solar system are reported to be approximately 55 °C.



Heat is delivered to the greenhouse space by three modes:

The 400 ft² unglazed solar panel described in the previous paragraph (mounted inside the greenhouse along the entire length of the north wall) is dual-purpose and is used to deliver radiant heat to the greenhouse during periods of heating demand.

An in-floor hydronic radiant tubing system is installed in a perimeter concrete slab within the

greenhouse.

Radiant and convective heat losses to the space occurring from the heated water circulating

through the fish tanks and hydroponic beds.

The system configured as observed in December 2011 (with only the small boiler operational) was apparently unable to meet heating needs during the coldest winter periods. We understand the space temperature in the greenhouse would occasionally drop to 11 or 12 °C during particularly cold nights. This is expected to be rectified with the addition of the 80 kW boiler. Cooling and ventilation is provided by a propeller exhaust fan and gravity dampers. An added feature of the existing heating system is a network of boreholes intended to function as a ground thermal mass for storing excess solar energy from the solar panels. We understand the system consists of eight 75-foot deep vertical boreholes installed under the greenhouse (near where the fish tanks are positioned). Each of the boreholes was fitted with high density polyethylene (HDPE) heat exchange tubing. We understand the intent was to circulate excess heat from the solar panels into the boreholes during the summer to warm the ground mass surrounding the boreholes and then to draw the heat from the ground by passive means (i.e., without using a heat pump) during the winter. Drilling logs for the boreholes were not available for our review, but standard geoexchange drilling practice in the region usually involves drilling nominal 4-inch diameter boreholes with 0.75-inch HDPE tubing within the boreholes. We understand that the boreholes were positioned with 7 feet of bore-to-bore separation. This is a much closer separation than the 20 to 30 feet of separation that is common for typical geoexchange system design in northern climates. We understand that the rationale for the close separation was to encourage thermal interference between the boreholes to increase the temperature of the stored heat (to improve the likelihood for being able to rely on passive heat exchange without a heat pump). However, while the close spacing helps to increase the temperature of the thermal store, it also limits the overall thermal capacity of the store which is a function of the soil volume between the bores. During initial operation for a limited time during the autumn of 2011, we understand the maximum achieved temperature of fluid in the borehole piping was approximately 22°C, which is not high enough to provide direct space or water heating by passive heat exchange without using a heat pump. Further testing of the system is ongoing during the Spring of 2012 and will continue. It is possible that the charging of the system with heat may need to occur over several seasons to gain the full benefit from the thermal store. However, the higher the temperature of thermal store becomes, the less able that it is to absorb heat from the solar system.



4.3 Proposed Expansions or Renovations

Future expansion or alterations may include moving the fish tanks out of the greenhouse into a separate structure and perhaps adding an additional greenhouse. However, at the time of the site visit, the expansion plans seemed neither fixed nor imminent. 4.4 Base Case Energy Analysis

The base case energy analysis corresponds to the wood boilers (40 + 80 kW boilers) in combination with the solar system serving the existing operation of the facility. Peak heating demand and annual heating energy consumption were estimated using DOE2 energy modeling software. Key modeling inputs to the DOE2 energy software include:

Operation: Year-round operation with 6 fish tanks and new boiler operating and able to meet required space temperatures

Weather file: Prince George

Utility rates1: Electricity BCH 1100 (Residential), Wood $4.31/MBtu

Internal Gains: Negligible (no lighting or other significant gains noted)

Building Envelope: Double poly U=0.71, SC=0.65 1 air change per hour infiltration, 2000 cubic feet per minute ventilation/cooling

Efficiency of Existing

System: Wood boiler 85% full load efficiency. Solar panels provide 150 GJ (142 MBtu) of heat a year, adjusted monthly for solar irradiation and assigned during daylight hours. Solar storage tank losses of 285 Btu/h per °F (calibrated to fit with observations of a maximum tank temperature of 55°C)

The duration of heating system loads (presented as a percentage of the peak load) are presented in Figure 1. The plot is derived from historical climatic data for the specific region in conjunction with heat loss/gain performance assumptions for the facility. It shows how many hours in a year the heating system must operate at a given heating capacity. For example, it becomes clear from Figure 1 that 100% of the peak heating load is only required for very few hours each year (extreme left of the plot) but 10% of the peak heating load is required for almost half of the year. This information is useful for analysis and design purposes because it describes both the intensity of the heating load and the cumulative duration of different heating intensities throughout a typical year. Figure 1 shows the net heating load profile (the residual heating load not met by the solar panel heating) has three components labeled Sections A, B and C. Section A shows that the accumulated duration of loads greater than 70% of the peak load is relatively short (loads exceeding 70% of the peak load occur only for about 400 hours in a typical year). The middle part of the profile (Section B) shows that about 3,000 heating hours occur at load intensities greater than 30% of peak load. At the lower heating intensity end of the curve (Section C), the plot is strikingly different from the typical long gradually diminishing tail shape that often develops. In this case the tail is truncated because lower end loads in the summer and shoulder season periods are often met by the solar panel heating.




Total annual heating load is 446 GJ (423 MBtu). With about one third being met by the solar panels, the net annual heating load is 300 GJ (284 MBtu), at a peak load of 47.8 kW (163 MBH). Equivalent full load heating hours (EFLh), which is the ratio of the annual heat demand to peak demand is 1,742 EFLh (with solar panel heating considered) and 2,595 EFLh (without accounting for the solar panel heating).

Figure 1. Heating profile plot for Site E Aquaponics Facility (net load not met by solar panel heat)

Monthly estimated heating system requirements are illustrated in Figure 2. Whereas the plot in Figure 1 shows the cumulative duration of loads at or above a selected heating intensity, Figure 2 shows a month-by-month account of heating demand as it occurs in a typical year.

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Figure 2. Month-by-month heat demand chart for Site E aquaponics facility (net load not met by solar

panel heat)

Annual energy consumption for the aquaponics facility is estimated to be:


Wood: 428.6 MBtu. Total annual GHG emissions are estimated to be only 0.43 tonnes CO2e because heating with wood is considered to be GHG emission neutral. 4.5 Potential Energy Conservation Opportunities

Planning for energy system upgrades should routinely consider strategies to reduce the magnitude of the load through energy conservation measures. Our review suggests the following conservation measures warrant consideration:

The existing thermal mass tank (accepting heat from the boilers and solar array should be better insulated (further analysis of solar thermal mass storage follows in subsequent section).

Insulation of piping and fittings throughout the heating distribution system should be checked and improved where gaps are identified.

The owner has commented that the temperatures within the greenhouse often climb to 45°C during sunny, hot days. Currently this heat is exhausted to the atmosphere by ventilation fans. The Owner has considered implementing a heat recovery system to harness and then reuse heat from the ventilation, with a preference to rely on passive technology (i.e., without using a heat pump) to transfer the heat. While heat recovery could be implemented, there are practical temperature constraints that limit the effectiveness of passive heat recovery systems. Also, there is the limitation stemming from the

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mismatched occurrence of ventilation heat availability with the occurrence of demand for the heat. Thermal mass storage considerations that relate to this constraint are addressed in a subsequent section of this report.

5.0 Site Characteristics The aquaponics facility is situated in the circle highlighted on the aerial photograph in Figure 3. The aerial photography dates from prior to construction of the greenhouse (which was erected in June 2010). The greenhouse is located west of the structure that appears in the photo. Most of the land area on the property is quite heavily wooded as shown in Figure 3, though there are cleared areas amounting to perhaps 2 to 3 ha surrounding the greenhouse and residence. The site is relatively flat lying likely representative of a glacial plain that is underlain by deposits of glacial till. Thick snow cover during the site visit prevented direct observation of soil surfaces, cutbank exposures, or groundcover. Information from the Owner suggests shallow soils in the upper 1.5 to 3 m consists of fine-grained clayey soils with a shallow water table.

Figure 3. Dated aerial view of Site E (prior to construction of greenhouse)

100

metres

0





Geological mapping incorporated within the BC Water Atlas online geographic information system.

Lithology descriptions from BC Ministry of Environment water well drill logs for three water wells located within 700 m of the site, accessed from the BC Water Atlas database shown as Wells A, B, and C in Figure 4.

Thermal conductivity and diffusivity values (key properties of soils and/or bedrock that govern how heat transfers through soil/bedrock) for shallow and deeper soils were estimated with reference to Soil and Rock Classification for the Design of Ground-Coupled Heat Pump Systems, Electric Power Research Institute, 1989, and Ground-Source Heat Pumps; Design of Geothermal Systems for Commercial and Institutional Buildings, Kavanaugh and Rafferty, ASHRAE, 1997, and by direct professional experience.

Figure 4. Water well locations within 700 m of subject site

(image and datapoints from BC Ministry of Environment BC Water Atlas)

Based on climatic data and measurements we have made at other locations in northern BC, we expect the deep ground temperature at the site to be approximately 6 to 7°C.

SUBJECT SITE



5.1.1 Upper Soils Shallow soils at the site (between a depth of 1.2 m to 3.0 m relevant for analysis of horizontal GHX systems) are expected to consist primarily of glacial till sediments. Based on information provided by the Owner and information gathered from logs for nearby water wells, the soils are expected to be fine-grained (mostly clay and perhaps also accompanied by some silt and fine sand). One of the water wells, Water Well C, on Figure 4 suggests a potential for gravel clasts to occur within the upper clay. Estimated thermal properties of the soils:


Thermal diffusivity3: 0.07 m2/day (0.7 ft2/day) 5.1.2 Bedrock The bedrock underlying the site is mapped as Takla Group sedimentary bedrock described as mudstone, siltstone, and shale. Thermal properties common for this type of bedrock:


Thermal diffusivity: 0.07 to 0.09 m2/day (0.7 to 1.0 ft2/day) Bedrock formations typically have better heat exchange properties than unconsolidated soils due to their higher density. However, in this case the bedrock is expected to be relatively soft and the difference in thermal properties between the upper glacial till soils and the underlying bedrock is expected to be less significant for this site than for many other sites in BC. The logs for water wells A, B, and C do not definitively indicate the depth at which the bedrock was encountered. Our interpretation of the cuttings descriptions in the logs suggests that bedrock was likely encountered at a depth of 85 feet in Well A, 115 feet in Well B, and 80 feet in Well C. 5.1.3 Groundwater To satisfy a reasonable base-load portion of the Site E heating load with a groundwater open loop type of system, a groundwater extraction rate of 15 to 30 USgpm (57 to 114 L/min) or higher would be required. The water well database records suggest that Well A is situated on the subject farm property and we presume that it provides the current water supply for the farm. The database indicates that it was installed in 1971 and at the time of installation was reported to yield 40 USgpm. No information was provided in the database regarding water chemistry information. Well depths and yield estimates for the three wells are summarized below:

Well A 30.5 m (100 ft) 152 L/min (40 USgpm) (bedrock interpreted at 85 ft)

Well B 79.3 m (260 ft) 38 L/min (10 USgpm) (bedrock interpreted at 115 ft)

Well C 97.6 m (320 ft) 57 L/min (15 USgpm) (bedrock interpreted at 80 ft)




5.1.4 Surface Water There is a lake located near the property as shown in Figures 3 and 4. However, the lakeshore is not on the subject property and the distance from the location of the facility to the lake is about 600 m.

6.0 Geoexchange Options Appropriate sizing of a geoexchange system is required to balance installation costs versus annual energy savings. In commercial settings, geoexchange systems are often sized to serve only a base load portion of the heating capacity. Additional geoexchange capacity that would be required to handle rarely occurring peak loads often does not operate enough hours of the year to generate a meaningful return on investment. The duration of heating loads originally presented in Figure 1 are shown again in Figure 5 with the proposed heat pump capacity. Viewing the annual heating requirements in this way illustrates that the facility experiences heating loads near the peak load for only very short periods in a typical year. Therefore, sizing a geoexchange system to meet the full peak load is not favoured because the full installed capacity would very rarely have an opportunity to generate a return on the investment. For this facility, we have examined two geoexchange system scenarios:

Scenario 1: Sized to meet 30% of the peak heating load with a 5 nominal ton heat pump: - Peak heating delivered by geoexchange: 14 kW (48 MBH) - Annual heat delivered by geoexchange: 198 GJ (188 MBtu) - Equivalent full load hours: 3,917 EFLh

Scenario 2: Sized to meet 60% of the peak heating load with a 10 nominal ton heat pump. - Peak heating delivered by geoexchange: 28 kW (96 MBH) - Annual heat delivered by geoexchange: 291 GJ (276 MBtu) - Equivalent full load hours: 2,875 EFLh

These scenarios are plotted on Figure 5 where the two different sized heat pumps serve the cumulative load that occurs below the respective dashed lines.



Figure 5. Duration of heating requirements as a percentage of peak heating load for Site E aquaponics

facility illustrating proposed heat pump capacity for two different heat pump size scenarios

6.1 GHX Option Comparison

The available GHX options (vertical closed-loop, horizontal closed-loop, groundwater open-loop, and

surface water open-loop) are evaluated in Table 1

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Table 1. Comparison of GHX Options at Site E Aquaponics Facility



H-GHX

Trenched horizontal

GHX (closed-loop)

High H-GHX systems can be very cost effective for certain ground conditions where low cost rapid trenching methods can install heat exchange (HX) pipe quickly and reliably. In many settings there is often insufficient space to install enough horizontal ground loop capacity to serve a meaningful portion of the peak loads. However, many agricultural sites, including this site, have relatively large available areas surrounding the heated facility (though in this case brush clearing may be required).

The chain-trencher method is among the most cost-effective methods for H-GHX installation in southern climates where the ground heat exchange piping can be buried at depths less than 1.8 m. However, in northern climates the trenches need to be excavated to deeper depths of 2.5 to 3 m. The availability of chain trenchers that can reliably excavate trenches deeper than 2.5 m is quite limited, so it is more common in northern climates for H-GHX trenches to be installed with tracked excavators.

There is some cleared area near the greenhouse (2 or 3 ha) and we understand that more could be cleared if necessary.

H-GHX Size Estimate For Scenario 1, to meet the heat pump loads with the assumed soil properties and 3 m spacing between trenches, five trenches with a trench length of 125 m per trench, for a total trench length of approximately 625 m would be required. This would occupy an area of approximately 1,500 m2.

For Scenario 2, ten trenches with a trench length of 125 m per trench for a total trench length of 1,250 m would be required. This would occupy an area of approximately 3,375 m2

Constructability Based on the shallow soil description provided by the Owner and soil descriptions obtained from water well logs, trenches are expected to be readily constructible at the site. The presence of a shallow water table can sometimes cause construction challenges, but if the soil is clay rich as expected then the water ingress to the trenches is expected to occur slowly enough to be manageable.

Merits Lower cost than V-GHX option and more certainty of adequate performance and more certainty of construction cost than the GW-GHX option. Some of the cost could be internal if the Owner conducted the excavation work.

V-GHX


Moderate The vertical borehole option (V-GHX) is inherently the most versatile of all options because it requires much less land area than H-GHX options, and is less sensitive to site-specific conditions than open-loop groundwater. However, when other options are feasible, the V-GHX option is usually the most expensive of all options.





Based on the soil/bedrock conditions gathered for this site, we anticipate the cost for V-GHX drilling to be a factor of 2 or more times greater than the cost for installing equivalent H-GHX heat exchange capacity.

The eight 75-foot boreholes could be incorporated into a V-GHX system, but V-GHX systems are quite sensitive to the bore-to-bore spacing and at 7 feet bore to bore spacing, relatively poor performance would be expected.

GW-GHX


GHX (open-loop)

Moderate GW-GHXs can sometimes provide heat exchange at relatively low cost when compared with closed-loop options (particularly for large capacity systems where highly productive aquifers occur). The relatively constant temperature of deeper ground water sources can also lead to slightly higher geoexchange efficiencies.

Of the three water well logs reviewed, only the well that is believed to be on the subject farm property is reported to produce a sufficient yield of groundwater yield to support geoexchange heating on the scale contemplated.

It is possible that the existing well on the property could be considered for use as a geoexchange source, but the actual sustainable production rate for the well would need to be confirmed through careful testing and a new pump and control system would also be required.

Routing of the discharge water would also need to be carefully considered. To avoid dewatering the aquifer, it would be advisable to re-inject the water back to the source aquifer but at a sufficient distance away from the pumping well to avoid thermal short-circuiting. To re-inject the water back to the source aquifer, a new well would be required. Additionally, a pipeline to convey water from the production well to the heat pump and from the heat pump to the injection well would need to be installed.

From our experience, costs to implement a GW-GHX system could be similar as compared to the cost to develop an H-GHX system. However, because of uncertainty about the long-term sustainable yield and water chemistry of the groundwater, the GW-GHX is subject to greater overall uncertainty regarding the level of performance and longevity to be expected. Furthermore, GW-GHX systems typically require a higher level of ongoing maintenance.

This application is somewhat small to take full advantage of the attractive economies of scale that GW-GHX systems can sometimes provide.

SW-GHX

Surface water GHX

(open-loop)

Low The distance to the lake is considered too far for the SW-GHX option and we understand that the subject farm property does not extend to the lakeshore.



Based on information gathered, the most cost-effective option with greatest certainty regarding constructability and performance is the trenched horizontal closed-loop H-GHX option. 6.2 Proposed Conceptual Geoexchange Design

The proposed geoexchange system is depicted in a generalized schematic in Figure 6 and has the following features:

5 nominal tons (Scenario 1) or 10 nominal tons (Scenario 2) of water-to-water heat pumps piped in an injection style configuration to feed the hydronic heating distribution loop.

Geoexchange heating capacity satisfies approximately 30% (Scenario 1) and 59% (Scenario 2) of the peak residual heating load not met by the solar heating system, respectively. These capacities allow the geothermal heat pump system to meet 66% (Scenario 1) and 97% (Scenario 2) of the annual residual heating load not met by the solar heating system.

Staging priority: 1. Solar heating panel system. 2. Geoexchange heat pumps / or biomass boilers (interchangeable priority depending on

wood supply and labour availability). 3. Geoexchange heat pumps / or biomass boilers (interchangeable priority depending on

wood supply and labour availability).





Trench method: Excavated trench (excavator method)


Trench to trench separation: 3.0 m minimum


Heating Loads: As indicated in previous section for Scenarios 1 and 2 Heating only operation


SOLAR THERMAL COLLECTORS

TO / FROM HORIZONTAL

TRENCHED GHX

HP 2 HP 1

TO / FROM HYDRONIC HEATING

BOILER 1 BOILER 2

SOLAR STORAGE

TANK



Minimum entering source temperature to heat pump: -2 to -1 °C

Heat Pump COP: 3.2 at -1 °C entering source temperature


Overall trench length: Scenario 1: Approximately 625 m of trench (five trenches 125 m long)

Scenario 2: Approximately 1,250 m of trench (ten trenches 125 m long)

Area Required for GHX: Scenario 1: Approximately 1,500 m² Scenario 2: Approximately 3,375 m²

Note that the benefit for circulating excess solar heat into the horizontal trenched GHX was analyzed. Horizontal GHX are not particularly well-suited for long-term seasonal storage. While some benefit would occur, the incremental benefit was relatively small. Additionally, consideration was made to incorporating the existing borehole array (eight 75-foot boreholes) into the GHX. Although it may be possible to substitute one of the horizontal 125 m trenches with the cumulative 137 m borehole length, a careful assessment of the borehole piping configuration would be required to ensure a balanced flow regime (i.e., equal flow through all branches of the GHX network). 6.3 Ground Thermal Mass Storage for Seasonal Solar Storage

As part of this assessment, the Owner requested an analysis of ground thermal mass storage options to help improve utilization of the heat produced by the glazed panel solar system that he has already developed. The effectiveness of solar panel heating systems are constrained because they generate the most heat in the summer when little or no heating demand occurs and they produce limited heat in the winter when the heating demand is high. To be more effective, solar heating systems can benefit from thermal storage if the thermal store is capable of capturing excess solar heat during the summer months and preserving the solar supply so that it is available during the autumn and winter months. Thermal mass storage for solar shifting can be developed by various means including:

above ground insulated tanks filled with water

above ground insulated tanks filled with other fluid/material (such as phase-change fluids such as waxes or other fluids that provide thermal storage benefits known as latent heat benefits by changing phase from liquid to solid)

borehole thermal energy storage (BTES) using closed-loop network of geoexchange boreholes

aquifer thermal energy storage (ATES) using open-loop production and injection wells

underground insulated tanks filled with water or other fluid/material. The latter three options in the previous list are examples of geoexchange technologies adapted for thermal storage.



The Owner stipulated a desire to evaluate a thermal store compatible with a passive heat exchange delivery of the heat (meaning that the heat would need to be stored at a high enough temperature to allow direct use of the heat without the need for a heat pump). Further, the terms of the review stipulated that the thermal store have the following attributes:

consist of a below-ground insulated tank filled with well-sorted coarse gravel (with a high void ratio) and water to fill the voids in the gravel

sized and constructed so that a future greenhouse could be constructed on top of the below-ground tank (the gravel in the tank would offer structural support)

designed so that the heat would be stored at a temperature high enough that the stored heat could be distributed directly without the need for heat pumps.

constructible with local labour and equipment In addition to considering the below ground thermal storage option, we have also considered the benefits of adding to and improving the indoor above-ground thermal mass tank. Discussion Currently, heat from the solar system is stored in an un-insulated 8,000 L open storage tank. Excess heat is circulated into the eight vertical borehole ground heat exchangers, but these do not reach a high enough temperature to provide useful heating (by passive means) and therefore the heat circulated into the boreholes is essentially lost in the current configuration. Our analysis indicates the existing system in its current configuration is able to gainfully use 53 GJ (50 MBtu) of the 150 GJ (142 MBtu) of solar heat produced, or only about 35%. Most of this heat is used either immediately or within 24 hours of it being generated. The small un-insulated storage tank has little ability to retain heat for the long term. While capturing the remaining 65% of solar generated heat is attractive, it requires a long-term storage solution that will allow heat generated in summer to be used in the autumn and winter. If all the heat could be captured and shifted, the solar heating could conceivably provide all the required heating for the facility into early December without the use of the boiler. However, long-term storage is very difficult and costly to achieve, requiring large storage capacities and heavy insulation to reduce loss of the heat during the long duration period of storage. Improved indoor thermal mass tanks have lower losses as they are not exposed to ground or outdoor conditions, but their thermal storage capacity is limited by virtue of space limitations. The below ground thermal storage option (BGS) can provide very large storage capacities, but this option will have higher losses to the ground. Indoor Storage Tank Two sizes of insulated indoor storage tanks were considered; 2,000 USgallon (7,600 L) and 8,000 USgallon (30,300 L), both with R15 insulation. Results of the analysis are provided in Table 2.



Table 2. Indoor Above-ground Storage Option

Indoor Above-ground Tank Sizes Existing 2,100 gal, no

insulation 2,000 USgal, R15 8,000 USgal, R15

Non-utilized solar heat (MBtu) 92 (65%) 88 (62%) 84 (59%)

Resultant load reduction (MBtu) - 4 8

Although the insulated tanks reduce the amount of heat lost, the performance gain is rather insignificant. Because the tanks are small, they cannot store heat for the long term. Therefore heat generated in summer continues to be lost, although lower tank losses and increased capacity mean more heat can be shifted across a short term (such as for night time heating), when required. Below Ground Thermal Storage The starting point size for a below ground thermal storage (BGTS) was considered as 100 feet by 46 feet and 10 feet deep which would roughly correspond to the footprint area of a new greenhouse if a twin greenhouse were constructed (the BGTS would lie below the new greenhouse). The proposed system configuration is shown in Figure 7 and the assumed construction characteristics considered for the BGTS include:

Double layer high density polyethylene liner

R15 polystyrene insulation between the double liner layers (to keep the insulation dry)

Well-sorted coarse gravel matrix material with 40% void ratio

Thermal store medium consists of 60% gravel matrix and 40% water by volume

Density of gravel 165 lb/ft3 and specific heat 0.20 Btu/lb-°F

Density of water 62.4 lb/ft3 and specific heat 1.0 Btu/lb-°F

Weighted average of density 124 lb/ft3

Weighted average of specific heat 0.36 Btu/lb-°F Operational logic assumptions for the BGTS include:

Maximum temperature in thermal store not to exceed 60°C (140°F)

Minimum useful temperature of thermal store to avoid need for heat pump 32°C (90°F)

No temperature partitioning of the BGTS was assumed (note that temperature partitioning can be helpful in some circumstances where a mix of short-term and long-term storage requirements occur - in this case long-term storage is disproportionately required to gain meaningful energy saving benefits.



Figure 7. Conceptual schematic of proposed below-ground thermal store (BGTS) system

The solution for the most suitable sizing for a BGTS is an optimization exercise. The larger the volume of the BGTS the larger the thermal storage capacity, but the larger the BGTS the larger the surface area through which the heat is lost from the thermal store. If the full size tank is considered (100 x 46 x 10 ft) the BGTS would have a storage capacity of 103 MBtu. Losses were calculated based on two ground temperature scenarios; 1) sufficient groundwater seepage around the outside of the BGTS to result in temperatures in the soil at the margin of the BGTS of 7°C (45°F), and 2) soil temperatures at the BGTS margin warmed by the BGTS to 18 °C (65°F), which reduces the amount of heat loss from the BGTS. The initial BGTS size with 45°F surrounding ground temperatures was found to be too large, resulting in losses that exceeded the stored energy. BGTS sizes of 1/2, 1/4, and 1/8 the initial size were then analyzed, assuming the length of the BGTS was varied but the width was held constant at 46 feet and the depth was held constant at 10 feet.

SOLAR THERMAL COLLECTORS

INSULATED BELOW GROUND THERMAL

STORAGE (NOT TO SCALE)

TO / FROM HYDRONIC HEATING

BOILER 1 BOILER 2

SOLAR STORAGE

TANK



Table 3. Below-ground Storage Analysis Findings (Surrounding Soil Temperature at 45°F)

Surrounding Soil Temperature Assumed to be 45°F Existing Full size 1/2 size 1/4 size 1/8 size

Delayed boiler startup date NA NA Oct 10 Oct 22 Oct 12

BGS thermal capacity (MBtu) NA 103 52 26 13

Non-utilized solar heat (MBtu) 92 (65%) 92 (65%) 78 (55%) 74 (52%) 75 (53%)

Resultant load reduction (MBtu) - 0 14 18 17

Table 4. Below-ground Storage Analysis Findings (Surrounding Soil Temperature at 65°F)

Surrounding Soil Temperature Assumed to be 65°F Existing Full size 1/2 size 1/4 size 1/8 size

Delayed boiler startup date NA Sep 22 Oct 17 Oct 20 Oct 12

BGS thermal capacity (MBtu NA 103 52 26 13

Non-utilized solar heat (MBtu) 92 (65%) 82 (58%) 71 (50%) 73 (51%) 78 (55%)

Resultant load reduction (MBtu) - 10 21 19 14

As shown in Tables 3 and 4, as the size of the BGTS gets smaller the losses from it are reduced, but at the same time the available storage decreases, meaning some summer heat is not able to be captured and can`t be preserved. The load reduction is very similar for the one-quarter and one-eighth size at 45 °F ground temperature, and for one-half and one-quarter size at 65 °F ground temperature. Since ground temperatures cannot be precisely predicted, the optimal size would appear to be around one-quarter the initial capacity, or a storage capacity of 26 MBtu, which would provide good results regardless of ground temperature. Nevertheless, it should be noted that the benefits as compared to the existing system are quite small, only reducing the amount of non-utilized solar heat from 65% in the existing system to 50% in the best case scenario. To reduce losses further, a higher level of insulation would be required on the tank. There are many possibilities for increasing insulation levels combined with varying BTGS sizes. One analysis was performed comparing the performance of R15 to R25 insulation on the 1/2 size BTGS with 65 °F ground temperature, with results provided in Table 5. Table 5. Benefit Comparison of Increased Insulation, 65°F Surrounding Ground Temperature

1/2 Size Tank - R15 compared to R25 Insulation Existing 1/2 size – R15 1/2 size – R25

Boiler startup date NA Oct 17 Nov 2

GSF Storage Capacity (MBtu) NA 52 52

Heat lost (MBtu) 92 (65%) 71 (50%) 59 (41%)

Load reduction (MBtu) 21 33

Although increased insulation improves performance, it would require a great deal of insulation to reduce losses significantly. Heavy insulation becomes expensive and impractical. Although increased insulation results in a larger optimal BGTS in terms of performance, the additional cost of the insulation hinders the economic viability of the larger BGTS.



6.4 Energy Analysis

Horizontal GHX Geoexchange System The annual energy consumption for System Scenarios 1 and 2 were calculated using the same DOE2 model as the base case calculations. The results are presented in Table 7 and summarized below. Summary of performance expectations for System Scenario 1 as compared to base case:

Annual wood consumption is expected to decrease from 429 MBtu to 201 MBtu with a resulting cost reduction from $1,847 to $864 ($983 annual wood cost saving)

Annual electrical consumption is expected to increase from 17,265 kWh per year to 31,497 kWh with a resulting cost increase from $1,478 to $2,847 ($1,369 annual electricity cost increase)

Annual GHG emissions are expected to slightly increase from 0.43 to 0.79 tonnes CO2e (the GHG emissions increase because base case biomass combustion is considered GHG neutral).

Summary of performance expectations for System Scenario 2 as compared to base case:

Annual wood consumption is expected to decrease from 429 MBtu to 33 MBtu with a resulting cost reduction from $1,847 to $141 ($1,706 annual wood cost saving)

Annual electrical consumption is expected to increase from 17,265 kWh per year to 39,314 kWh with a resulting cost increase from $1,478 to $3,599 ($2,121 annual electricity cost increase)

Annual GHG emissions are expected to slightly increase from 0.43 to 0.98 tonnes CO2e (the GHG emissions increase because base case biomass combustion is considered GHG neutral).

Below Ground Thermal Energy Store The annual energy consumption for the full-size and 1/4-size below-ground thermal energy store was also calculated using the same DOE2 model as the base case calculations. The results are presented in Table 7 and summarized below. Summary of performance expectations for 1/4-size below-ground thermal energy store as compared to base case:

Annual wood consumption is expected to decrease from 429 MBtu to 406 MBtu with a resulting cost reduction from $1,847 to $1,750 ($97 annual wood cost saving)

Annual electrical consumption is expected to remain unchanged.

Annual GHG emissions are expected to remain unchanged (since biomass combustion and solar are both considered GHG emission neutral).

The performance for the full size thermal energy store is virtually the same as the 1/4 size store. 6.5 Geoexchange and Below-ground Thermal Store Cost Estimates

Preliminary cost estimates for the proposed geoexchange system and below-ground solar thermal energy store (above the base case costs) are summarized in Tables 6a through 6d.



Table 6a Estimated additional costs of proposed geoexchange Scenario 1 (5 nominal ton system)

Item Estimated Cost

Horizontal Ground Heat Exchanger $7,500 Heat Pumps (5 nominal tons) $10,000 Heat Pump Installation $5,000 Controls $5,000 Engineering $5,000

Total $32,500

Table 6b Estimated additional costs of proposed geoexchange Scenario 2 (10 nominal ton system)

Item Estimated Cost


Table 6c Estimated additional costs of proposed 1/4-size below-ground thermal store tank

Item Estimated Cost

R15 insulation on bottom/sides of tank (top is floor of greenhouse): 2570 ft2 @ $1.50/ft2 $3,900 HDPE Liner (double layer liner): 5,140 ft2 @ $1.00/ft2 $5,140 Excavation: 2 days@ $1,250/day $2,500 Gravel placement with excavator in layer lifts: 3 days @ $1,250/day $3,750 Gravel: 425 yd3 or 22 truck +pup loads at 1 hr truck time per load: 22 hr @ $80/hr $1,760 Distribution mat tubing: 10,000 lineal feet @ $0.40/ft Labour: 2 men for one week: 100 man hours @ $65/hr

$4,000 $6,500

Estimated Total $30,000

Table 6d Estimated additional costs of proposed full-sizebelow-ground thermal store tank

Item Estimated Cost

R15 insulation on bottom/sides of tank (top is floor of greenhouse): 7,520 ft2 @ $1.50/ft2 $11,300 HDPE Liner (double layer liner): 15,040 ft2 @ $1.00/ft2 $15,040 Excavation: 6 days@ $1,250/day $7,500 Gravel placement with excavator in layer lifts: 9 days @ $1,250/day $11,250 Gravel: 1700 yd3 or 85 truck +pup loads at 1 hr truck time per load: 85 hr @ $80/hr $6,800 Distribution mat tubing: 40,000 lineal feet @ $0.40/ft Labour: 2 men for three weeks: 300 man hours @ $65/hr

$16,000 $19,500

Estimated Total $90,000




There are no specific technical challenges that would limit the installation of the proposed geoexchange system or below-ground thermal energy store in this setting. The available land area is capable of providing ground heat exchange capacity for meeting the loads described in the conceptual design. The Owner will need to consider whether burial of piping is compatible with long-range plans for the farm. 7.2 Financial Feasibility

The financial costs of the base case and geoexchange system scenarios for the greenhouse are summarized in Table . Under current conditions, the proposed geoexchange system has a Chabot Profitability Index4 (CPI) of -0.67 and an IRR of -0.4%, and is therefore not considered financially viable Table 7. Financial Evaluation of Proposed Geoexchange System for Existing Greenhouse


Option Baseline Geoexchange 5

Nominal Tons

Geoexchange 10

Nominal Tons

Ground Solar

Thermal Storage

1/4 Tank

Ground Solar

Thermal Storage

Full Tank

Weather file Prince George Prince George Prince George Prince George Prince George

Electricity Rate BCH 1100 Res BCH 1100 Res BCH 1100 Res BCH 1100 Res BCH 1100 Res

Blended Electricity Cost ($/kWh) 0.086$ 0.090$ 0.092$ 0.086$ 0.086$

Natural Gas Rate

Blended Natural Gas Cost ($/GJ)

Average Cost of Wood ($/Mbh) 4.3100$ 4.3100$ 4.3100$ 4.3100$ 4.3100$

Heat Pump Capacity (nominal tons) 5 10 0 0

Nominal Heat Pump Capacity (MBH @ 100° ELT, 30°

EST for Closed Loop)

48 96 0 0

Nominal Heat Pump Capacity as % of peak 30% 59% 0% 0%

Load met by Heat Pump (Mbtu) 188 276 0 0

% total load met by Heat Pump 66% 97% 0% 0%

Peak load met by Heat Pump (MBH) 58 104 0 0

Electricity Consumption (kWh) 17,265 31,497 39,314 17,265 17,265

Electricity Cost 1,478$ 2,847$ 3,599$ 1,478$ 1,478$

Wood Consumption (MBtu) 428.6 200.5 32.6 406.1 404.6

Wood Cost 1,847$ 864$ 141$ 1,750$ 1,744$


Propane Cost

Total Energy Consumption (Mbtu) 465 298 165 444 442

Total Energy Cost 3,325$ 3,711$ 3,740$ 3,228$ 3,222$

Energy Cost Savings (386)$ (415)$ 97$ 103$

Additional Capital Cost 22,000$ 44,000$ 30,000$ 90,000$

Project Internal Rate of Return -0.4% -0.5% 3.6% 3.3%

Chabot Profitability Index -0.67 -0.60 -0.34 -0.36

Annual GHG Emissions (tonnes CO2e) 0.43 0.79 0.98 0.43 0.43

Annual GHG Reduction (tonnes CO2e) -0.4 -0.6 - -

Potential Annual GHG Offset Value ($25/tonne

CO2e)

-$ -$ -$ -$




All else being equal, any of the following conditions would lead to financial viability at a CPI of 0.3. 5 Nominal Ton Scenario:


an average cost of wood of $ 12.23 / MBH,


a capital grant of $ 26,620. 10 Nominal Ton Scenario:


an average cost of wood of $ 12.75 / MBH,


a capital grant of $ 49,210.


It is technically feasible to adapt a typical geoexchange heating system for the Site E Aquaponics Facility.

The horizontal trenched method of ground heat exchange appears best suited for this site, though there is less definitive evidence suggesting groundwater open loop system may also be suited. Other ground heat exchange options are less suited to the site setting due to higher costs or they are not technically feasible.

A below-ground thermal energy store is technically feasible that would allow some of the un-utilized solar energy that is currently wasted in the summer to be captured and used in the fall and early winter. However, technical constraints cause the amount of heat that can be captured and shifted for later gainful use to be quite small.

While technically feasible, economic analyses indicate that neither the typical geoexchange retrofit nor the below-ground thermal store meet profitability criteria. This finding is principally due to the wood biomass boiler base case scenario and the relatively low wood energy cost in the region.

Because wood biomass combustion is considered to be GHG emission neutral, neither the typical geoexchange retrofit nor the below-ground thermal energy store would result in GHG emission reductions.

Operating and maintaining wood boilers is labour intensive and requires constant minding. Developing a geoexchange system (and to a lesser extent developing a below-ground thermal store to improve solar effectiveness) could reduce labour and minding needs.



9.0 Recommended Next Steps The business case has been determined to be unprofitable for the energy system developments considered in this study. Unless the Owner is motivated to proceed based on the merits of reducing labour and minding needs alone, then no further action appears warranted at this time.

Appendix B: Utility Rates Used

JDQ Engineering Limited B144

Appendix B – Utility Rates Used FortisBC electrical and natural gas rates, BC Hydro electrical rates, and assumed propane costs used in the economic evaluation for each site are listed below. Detailed explanations of these rates can be found in each utility’s tariff available on the web at FortisBC Tariffs and BC Hydro Tariff. Site A FBC Electric 21 - Commercial

Monthly charge $15.01 First 8000 kWh $0.0789/kWh Remaining kWh $0.0655/kWh First 40 kW - Remaining kW $7.84/kW 75% demand ratchet year round1

FBC Electric 30 - Commercial

Monthly charge $777.48 All kWh $0.0458/kWh All kW $7.56/kW 75% demand ratchet year round

FBC Gas 2 – Small Commercial

Monthly charge $24.82 Gas cost $9.7178/GJ ($8.228/GJ + $1.4898/GJ carbon tax) 3.09% franchise fee

FBC Gas 3 –Commercial


Propane $0.5962/L ($0.55/L + $0.0462/L carbon tax) Site B BC Hydro 1207 - Electric Plus

First 8000 kWh $0.0428/kWh Remaining kWh $0.0281/kWh

Propane $0.8462/L ($0.80/L + $0.0462/L carbon tax)

1 In addition to the amount of electricity used, commercial services often include a demand charge based on the rate of delivery

of electricity measured in kilowatts (kW) over a given period of time. The Billed Demand is the greatest of: i. twenty-five per cent (25%) of the Contract Demand , or ii. the maximum Demand in kW for the current billing month, or iii. seventy-five per cent (75%) of the maximum Demand in kW registered during the months previous eleven month period.

http://www.fortisbc.com/About/RegulatoryAffairs/Pages/default.aspx

http://www.bchydro.com/planning_regulatory/tariff_filings.html



Site C BC Hydro 1151 – Residential (Farm)

Monthly charge $4.70 All kWh $0.0784/kWh

FBC Gas 2 – Small Commercial


FBC Gas 3 –Commercial

Monthly charge $132.43 Gas cost $8.9978/GJ ($7.508/GJ + $1.4898/GJ carbon tax)

Site D BC Hydro 1500 – Medium General Service

Monthly charge $5.64 First 14800 kWh $0.0872/kWh Remaining kWh $0.0444/kWh First 35 kW - Next 115 kW $4.51/kW Remaining kW $8.66/kW 50% demand ratchet Nov - Mar

FBC Gas VI – Large Commercial Rate 1


FBC Gas VI – Large Commercial Rate 2


Site E BC Hydro 1100 – Residential

Monthly charge $4.42 First 666 kWh $0.0667/kWh Remaining kWh $0.0962/kWh

Wood $4.31/MBtu Theoretical Scenarios BC Hydro 1300 – Small General Service


BC Hydro 1500 – Medium General Service




BC Hydro 1600 – Large General Service


FBC Electric 20 – Small Commercial


FBC Electric 21 - Commercial

Monthly charge $15.01 First 8000 kWh $0.0789/kWh Remaining kWh $0.0655/kWh First 40 kW - Remaining kW $7.84/kW 75% demand ratchet year round

FBC Electric 30 – Large Commercial

Monthly charge $777.48 All kWh $0.0458/kWh All kW $7.56/kW 75% demand ratchet year round

FBC Gas 2 – Small Commercial (Harmonized)


FBC Gas 3 –Commercial (Harmonized)

Monthly charge $132.58 Gas cost 9.3358/GJ ($7.846/GJ + $1.4898/GJ carbon tax) 3.09% franchise fee

Propane $0.5962/L ($0.55/L + $0.0462/L carbon tax)

Appendix C: Theoretical Scenario Evaluations

JDQ Engineering Limited C147

APPENDIX C: THEORETICAL SCENARIO EVALUATIONS

SITE A - GREENHOUSE WITH ARTIFICIAL LIGHTING AND CO2 ENRICHMENT - SOUTHERN INTERIOR

Option Baseline, natural gas

Horizontal GeoX, natural gas

Open Loop GW GeoX, natural gas

Baseline, propane

Vertical Good GeoX, propane

Vertical Poor Loop GeoX, propane

Open Loop GW GeoX, propane

Weather file Oliver Oliver Oliver Oliver Oliver Oliver Oliver

Electricity Rate Blended BCH 1600 LGS BCH 1600 LGS BCH 1600 LGS BCH 1600 LGS BCH 1600 LGS BCH 1600 LGS BCH 1600 LGS

Electricity Cost ($/kWh) $0.07 $0.07 $0.07 $0.07 $0.07 $0.07 $0.07

Natural Gas Rate Blended FBC Rate3 FBC Rate2 FBC Rate2 FBC Rate3 FBC Rate2 FBC Rate2 FBC Rate2

Natural Gas Cost ($/GJ) $10.06 $10.29 $10.29

Blended Propane Rate ($/L) $0.596 $0.596 $0.596 $0.596

Heat Pump Capacity (nominal tons) 20 20 20 20 20

Nominal Heat Pump Capacity (MBH @ 100° ELT, 30° m EST for Closed Loop, 50° EST for Open Loop)

233 302 233 233 302

Nominal Heat Pump Capacity as % of peak 16% 21% 16% 16% 21%

Load met by Heat Pump (Mbtu) 416 429 416 416 429

% non‐CO2 load met by Heat Pump 70% 72% 70% 70% 72%

% total load met by Heat Pump 21% 21% 21% 21% 21%

Peak load met by Heat Pump (MBH) 291 286 291 291 286

Electricity Consumption (kWh) 1,421,422 1,462,328 1,460,887 1,421,422 1,462,328 1,462,328 1,460,887

Electricity Cost $99,763 $102,821 $102,538 $99,763 $102,821 $102,821 $102,538


Natural Gas Cost $22,101 $17,677 $17,522

Propane Consumption (L) 86,814 67,896 67,896 67,292

Propane Cost $51,758 $40,480 $40,480 $40,120

Total Energy Consumption (Mbtu) 4,852 4,991 4,986 6,934 6,620 6,620 6,600

Total Energy Cost $121,864 $120,498 $120,060 $151,521 $143,301 $143,301 $142,657

Energy Cost Savings $1,366 $1,804 $8,220 $8,220 $8,864

Additional Capital Cost $66,000 $82,500 $88,000 $209,000 $82,500

Project Internal Rate of Return 3.50% 4.30% 15.40% 8.10% 17.30%

Chabot Profitability Index ‐0.23 ‐0.20 0.66 0.05 0.82

Annual GHG Emissions (tonnes CO2e) 146.1 123 122.2 169.6 141.4 141.4 140.4

Annual GHG Reduction (tonnes CO2e) 23.1 23.9 28.2 28.2 29.2

Potential Annual GHG Offset Value ($25/tonne CO2e) $576.50 $596.62 $704.66 $704.66 $728.87



SITE A - GREENHOUSE WITH ARTIFICIAL LIGHTING AND CO2 ENRICHMENT - SOUTHERN INTERIOR (con’t)

Option Open Loop GW Geox, natural gas, FBC Elec

Baseline, propane, FBC Elec

Horizontal GeoX, propane, FBC Elec

Open Loop GW GeoX, propane, FBC Elec

Weather file Oliver Oliver Oliver Oliver

Electricity Rate Blended FBC 21 Comm FBC 21 Comm FBC 21 Comm FBC 21 Comm

Electricity Cost ($/kWh) $0.09 $0.09 $0.09 $0.09

Natural Gas Rate Blended FBC Rate2 FBC Rate3 FBC Rate2 FBC Rate2

Natural Gas Cost ($/GJ) $10.29

Blended Propane Rate ($/L) $0.596 $0.596 $0.596

Heat Pump Capacity (nominal tons) 20 20 20

Nominal Heat Pump Capacity (MBH @ 100° ELT, 30° m EST for Closed Loop, 50° EST for Open Loop)

302 233 302

Nominal Heat Pump Capacity as % of peak 21% 16% 21%

Load met by Heat Pump (Mbtu) 429 416 429

% non‐CO2 load met by Heat Pump 72% 70% 72%

% total load met by Heat Pump 21% 21% 21%

Peak load met by Heat Pump (MBH) 286 291 286

Electricity Consumption (kWh) 1,460,887 1,421,422 1,462,328 1,460,887

Electricity Cost $130,915 $127,340 $131,211 $130,915

Natural Gas Consumption (GJ) 1,703

Natural Gas Cost $17,522


Propane Cost $51,758 $40,480 $40,120

Total Energy Consumption (Mbtu) 4,986 6,934 6,620 6,600

Total Energy Cost $148,438 $179,098 $171,690 $171,035

Energy Cost Savings $1,003 $7,408 $8,063

Additional Capital Cost $82,500 $66,000 $82,500

Project Internal Rate of Return 2.40% 17.80% 16.00%

Chabot Profitability Index ‐0.31 0.86 0.71

Annual GHG Emissions (tonnes CO2e) 94.4 142.6 113.6 112.7

Annual GHG Reduction (tonnes CO2e) 24.6 29 29.9

Potential Annual GHG Offset Value ($25/tonne CO2e) $615.37 $724.09 $747.62



SITE A ‐ GREENHOUSE WITH ARTIFICIAL LIGHTING AND CO2 ENRICHMENT ‐ NORTHERN





Vertical Good GeoX, propane, FBC Elec

Vertical Poor GeoX, propane, FBC Elec


Weather file Prince George Prince George Prince George Prince George Prince George Prince George Prince George

Electricity Rate Blended BCH 1600 LGS BCH 1600 LGS BCH 1600 LGS BCH 1600 LGS BCH 1600 LGS BCH 1600 LGS BCH 1600 LGS





Heat Pump Capacity (nominal tons) Pump (Mbtu) 20 20 20 20 20

Nominal Heat Pump Capacity (MBH @ 100° ELT, 30° EST for Closed Loop, 50° EST for Open Loop)

233 278 233 233 278



% non‐CO2 load met by Heat Pump 59% 61% 59% 59% 61%

% total load met by Heat Pump 20% 21% 20% 20% 21%


Electricity Consumption (kWh) 1,477,529 1,527,865 1,529,520 1,477,529 1,527,865 1,527,865 1,529,520



Natural Gas Cost $27,768 $22,264 $22,087


Propane Cost $66,057 $52,169 $52,169 $51,722






Chabot Profitability Index ‐0.13 ‐0.17 0.89 0.16 1.01

Annual GHG Emissions (tonnes CO2e) 178 149.6 148.7 208 173.3 173.3 172.2


Potential Annual GHG Offset Value ($25/tonne CO2e) $709.88 $732.71 $867.68 $867.68 $895.59



SITE A ‐ LIT GREENHOUSE WITHOUT CO2 ENRICHMENT ‐ SOUTHERN INTERIOR


Closed Loop GeoX, natural gas


Baseline, propane

Closed Loop GeoX, propane


Weather file Oliver Oliver Oliver Oliver Oliver Oliver

Electricity Rate Blended BCH 1600 LGS BCH 1600 LGS BCH 1600 LGS BCH 1600 LGS BCH 1600 LGS BCH 1600 LGS

Electricity Cost ($/kWh) $0.07 $0.07 $0.07 $0.07 $0.07 $0.07

Natural Gas Rate Blended FBC Rate3 FBC Rate2 FBC Rate2 FBC Rate3 FBC Rate2 FBC Rate2



Heat Pump Capacity (nominal tons) Pump (Mbtu) 20 20 20 20


233 302 233 302



% non‐CO2 load met by Heat Pump 83% 84% 83% 84%

% total load met by Heat Pump 83% 84% 83% 84%


Electricity Consumption (kWh) 1,421,196 1,585,554 1,577,367 1,421,196 1,585,554 1,577,367

Electricity Cost $99,744 $108,850 $108,358 $99,744 $108,850 $108,358

Natural Gas Consumption (GJ) 2241 374 340

Natural Gas Cost $22,512 $4,077 $3,735


Propane Cost $52,795 $8,803 $8,007

Total Energy Consumption (Mbtu) 4851 5,412 5,384 5,766 5,706

Total Energy Cost $122,256 $112,927 $112,093 $152,539 $117,653 $116,365

Energy Cost Savings $9,329 $10,163 $34,886 $36,174

Additional Capital Cost $81,400 $82,500 $81,400 $82,500

Project Internal Rate of Return 18.30% 19.30% 54.60% 55.80%

Chabot Profitability Index 0.94 1.01 4.64 4.76

Annual GHG Emissions (tonnes CO2e) 148.3 58.4 56.5 172.3 62.4 60.2

Annual GHG Reduction (tonnes CO2e) 89.8 91.7 109.8 112.1

Potential Annual GHG Offset Value ($25/tonne CO2e) $2,245.63 $2,293.24 $2,745.50 $2,802.15



SITE A ‐ LIT GREENHOUSE WITHOUT CO2 ENRICHMENT ‐ SOUTHERN INTERIOR (con’t)

Option Baseline, natural gas, FBC Elec

Closed Loop GeoX, natural gas, FBC Elec

Open Loop GW GeoX, natural gas, FBC Elec


Vertical Good GeoX, propane, FBC Elec

Weather file Oliver Oliver Oliver Oliver Oliver

Electricity Rate Blended FBC 21 Comm FBC 21 Comm FBC 21 Comm FBC 21 Comm FBC 21 Comm

Electricity Cost ($/kWh) $0.09 $0.09 $0.09 $0.09 $0.09

Natural Gas Rate Blended FBC Rate3 FBC Rate2 FBC Rate2 FBC Rate3 FBC Rate2


Blended Propane Rate ($/L) $0.60 $0.60

Heat Pump Capacity (nominal tons) Pump (Mbtu) 20 20 20


233 302 233



% non‐CO2 load met by Heat Pump 83% 84% 83%

% total load met by Heat Pump 83% 84% 83%


Electricity Consumption (kWh) 1,421,196 1,585,554 1,577,367 1,421,196 1,585,554

Electricity Cost $127,317 $139,988 $139,322 $127,317 $139,988

Natural Gas Consumption (GJ) 2,241 374 340

Natural Gas Cost $22,512 $4,077 $3,735

Propane Consumption (L) 88,553 14,765

Propane Cost $52,795 $8,803

Total Energy Consumption (Mbtu) 4851 5,412 5,384 6975 5,766

Total Energy Cost $149,829 $144,065 $143,057 $180,112 $148,791


Additional Capital Cost $81,400 $82,500 $118,800


Chabot Profitability Index 0.39 0.52 2.49

Annual GHG Emissions (tonnes CO2e) 121.3 28.3 26.6 145.3 32.3

Annual GHG Reduction (tonnes CO2e) 92.9 94.7 112.9

Potential Annual GHG Offset Value ($25/tonne CO2e) $2,323.70 $2,367.42 $2,823.57



SITE B ‐ SEASONAL GREENHOUSE ‐ LOWER MAINLAND

Option Baseline, natural

gas Horizontal GeoX, natural gas


Baseline, propane

Vertical (Good) GeoX, propane

Vertical (Poor) GeoX, propane


Weather file Abbotsford Abbotsford Abbotsford Abbotsford Abbotsford Abbotsford Abbotsford

Electricity Rate Blended BCH 1300 SGS BCH 1500 MGS BCH 1500 MGS BCH 1300 SGS BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS







844 1061 844 844 1061


Heat Pump Cut off point (MBH) 2187 2187 2187 2187 2187

Heat Pump Cut off point (%) 62% 62% 62% 62% 62%

Load met by heat pump (Mbtu) 4005 4229 4005 4005 4229

Peak load met by heat pump (MBH) 1033 1015 1033 1033 1015

Electricity Consumption (kWh) 92075 420,319 412,729 92075 420,319 420,319 412,729



Natural Gas Cost $92,638 $41,229 $38,481


Propane Cost $229,743 $100,024 $100,024 $93,090




Additional Capital Cost $431,200 $369,600 $554,400 $1,232,000 $369,600


Chabot Profitability Index 0.34 0.55 2.72 1.01 4.41

Annual GHG Emissions (tonnes CO2e) 492.9 224.1 209.1 597.3 269.5 269.5 251.4


Potential Annual GHG Offset Value ($25/tonne CO2e) $6,719.40 $7,094.26 $8,193.34 $8,193.34 $8,646.99



SITE B ‐ SEASONAL GREENHOUSE ‐ NORTHERN




Baseline, propane

Horizontal GeoX, propane


Weather file Prince George Prince George Prince George Prince George Prince George Prince George

Electricity Rate Blended BCH 1300 SGS BCH 1600 LGS BCH 1600 LGS BCH 1300 SGS BCH 1600 LGS BCH 1600 LGS







1688 1975 1688 1975


Heat Pump Cut off point (MBH) 3476 3476 3476 3476

Heat Pump Cut off point (%) 62% 62% 62% 62%

Load met by heat pump (Mbtu) 7159 7413 7159 7413

Peak load met by heat pump (MBH) 2036 1889 2036 1889

Electricity Consumption (kWh) 140,815 840,023 863,849 140,815 840,023 863,849



Natural Gas Cost $143,150 $51,947 $48,907


Propane Cost $357,203 $127,068 $119,398

Total Energy Consumption (Mbtu) 14,856 7,981 7,753 14,853 7,980 7,752











SITE B ‐ SEASONAL GREENHOUSE ‐ SOUTHERN INTERIOR




Baseline, propane




Electricity Rate Blended BCH 1300 SGS BCH 1600 LGS BCH 1600 LGS BCH 1300 SGS BCH 1600 LGS BCH 1600 LGS







1266 1592 1266 1592


Heat Pump Cut off point (MBH) 2722 2722 2722 2722

Heat Pump Cut off point (%) 62% 62% 62% 62%

Load met by heat pump (Mbtu) 4945 5222 4945 5222

Peak load met by heat pump (MBH) 1538 1513 1538 1513




Natural Gas Cost $102,809 $39,106 $35,688


Propane Cost $255,409 $94,667 $86,042







Annual GHG Emissions (tonnes CO2e) 548 215.6 197 664.1 258.7 236.2

Annual GHG Reduction (tonnes CO2e) 332.4 351 405.4 427.9




SITE B ‐ SEASONAL GREENHOUSE ‐ SOUTHERN INTERIOR (con’t)


Vertical (Good) GeoX, natural gas, FBC Elec

Vertical (Poor) GeoX, natural gas, FBC Elec



Weather file Oliver Oliver Oliver Oliver Oliver

Electricity Rate Blended FBC 20 SC FBC 21 Comm FBC 21 Comm FBC 21 Comm FBC 20 SC

Electricity Cost ($/kWh) $0.09 $0.09 $0.09 $0.09 $0.09


Natural Gas Cost ($/GJ) $9.48 $9.73 $9.73 $9.77

Blended Propane Rate ($/L) $0.60

Heat Pump Capacity (nominal tons) Pump (Mbtu) 168 168 168


1266 1266 1592


Heat Pump Cut off point (MBH) 2722 2722 2722

Heat Pump Cut off point (%) 62% 62% 62%

Load met by heat pump (Mbtu) 4945 4945 5222

Peak load met by heat pump (MBH) 1538 1538 1513

Electricity Consumption (kWh) 106,287 540,584 540,584 532,941 106287

Electricity Cost $9,105 $47,736 $47,736 $47,516 $9,105


Natural Gas Cost $39,106 $39,106 $35,688

Propane Consumption (L) 10842 428394

Propane Cost $102,809 $255,409

Total Energy Consumption (Mbtu) 10642 5,655 5,655 5,282 10639

Total Energy Cost $111,914 $86,842 $86,842 $83,204 $264,513


Additional Capital Cost $831,600 $1,848,000 $554,400


Chabot Profitability Index ‐0.10 ‐0.26 0.12

Annual GHG Emissions (tonnes CO2e) 546 205.4 205.4 186.9 662.1


Potential Annual GHG Offset Value ($25/tonne CO2e) $8,515.40 $8,515.40 $8,976.91



SITE C ‐ POULTRY BROILER FARM ‐ LOWER MAINLAND




Baseline, propane

Vertical (Good) GeoX, propane

Vertical (Poor) GeoX, propane


Weather file Abbotsford Abbotsford Abbotsford Abbotsford Abbotsford Abbotsford Abbotsford

Electricity Rate Blended BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS







422 530 422 422 530




Electricity Consumption (kWh) 80,944 212,317 199,777 80,944 212,317 212,317 199,777



Natural Gas Cost $17,950 $2,997 $2,996


Propane Cost $41,114 $6,288 $6,288 $6,286

Total Energy Consumption (Mbtu) 1,931 978 935 1,930 978 978 935





Chabot Profitability Index ‐0.28 ‐0.24 0.34 ‐0.01 0.59






SITE C ‐ POULTRY BROILER FARM ‐ NORTHERN


Vertical (Good) GeoX, natural gas

Vertical (Poor) GeoX, natural gas


Baseline, propane



Weather file Prince George Prince George Prince George Prince George Prince George Prince George Prince George

Electricity Rate Blended BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS



Natural Gas Cost ($/GJ) $9.82 $10.50 $10.50 $10.50




633 633 741 633 741




Electricity Consumption (kWh) 89,205 318,389 318,389 311,452 89,205 318,389 311,452


Natural Gas Consumption (GJ) 3,272 778 778 777

Natural Gas Cost $32,138 $8,165 $8,165 $8,157


Propane Cost $77,085 $18,325 $18,305




Additional Capital Cost $554,400 $1,062,600 $415,800 $462,000 $415,800


Chabot Profitability Index ‐0.29 ‐0.34 ‐0.24 0.63 0.75


Annual GHG Reduction (tonnes CO2e) 119.7 119.7 120 146.4 146.7




SITE C ‐ POULTRY BROILER FARM ‐ SOUTHERN INTERIOR


Vertical GeoX, natural gas


Baseline, propane

Vertical GeoX, propane



Electricity Rate Blended BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS







422 530 422 530







Natural Gas Cost $20,719 $5,956 $5,954


Propane Cost $48,271 $13,179 $13,174






Chabot Profitability Index ‐0.28 ‐0.25 0.5 0.59






SITE C ‐ POULTRY BROILER FARM ‐ SOUTHERN INTERIOR (con’t)


Vertical GeoX, natural gas, FBC Elec



Vertical GeoX, propane, FBC Elec



Electricity Rate Blended FBC 21 Comm FBC 21 Comm FBC 21 Comm FBC 21 Comm FBC 21 Comm FBC 21 Comm







422 530 422 530







Natural Gas Cost $20,719 $5,956 $5,954


Propane Cost $48,271 $13,179 $13,174






Chabot Profitability Index ‐0.30 ‐0.26 0.48 0.59






SITE D - POULTRY PROCESSING FACILITY


Refrigeration Heat Recovery, Horizontal GeoX, natural gas

Refrigeration Heat Recovery, Open Loop GW GeoX, natural gas

Baseline, propane

Refrigeration Heat Recovery, Horizontal GeoX, propane

Refrigeration Heat Recovery, Open Loop GW GeoX, propane

Weather file Victoria Victoria Victoria Victoria Victoria Victoria

Electricity Rate Blended BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS BCH 1500 MGS





Heat Pump Capacity (nominal tons) Pump (Mbtu) 6.5 6.5 6.5 6.5


52 68 52 68




Load met by heat recovery (Mbtu) 386 386 386 386

Peak Load met by heat recovery (MBH) 280 280 280 280




Natural Gas Cost $22,383 $15,194 $15,028


Propane Cost $52,469 $34,696 $34,310







Annual GHG Emissions (tonnes CO2e) 119 81.5 80.7 142.8 97.3 96.3


Potential Annual GHG Offset Value ($25/tonne CO2e) $935.46 $955.76 $1,137.41 $1,162.10



SITE D - POULTRY PROCESSING FACILITY (con’t)


Refrigeration Heat Recovery, Vertical (Good) GeoX, natural gas, FBC Elec

Refrigeration Heat Recovery, Vertical (Poor) GeoX, natural gas, FBC Elec

Refrigerationc Heat Recovery, Open Loop GW GeoX, natural gas, FBC Elec


Weather file Victoria Victoria Victoria Victoria Victoria

Electricity Rate Blended FBC 21 Comm FBC 21 Comm FBC 21 Comm FBC 21 Comm FBC 21 Comm

Electricity Cost ($/kWh) $0.10 $0.10 $0.10 0.098 $0.10


Natural Gas Cost ($/GJ) $10.05 $10.32 $10.32 10.32

Blended Propane Rate ($/L) $0.60

Heat Pump Capacity (nominal tons) Pump (Mbtu) 6.5 6.5 6.5


52 52 68




Load met by heat recovery (Mbtu) 386 386 386

Peak Load met by heat recovery (MBH) 280 280 280

Electricity Consumption (kWh) 276,982 298,267 298,267 298,740 276,982

Electricity Cost $26,954 $29,132 $29,132 29,197 $26,954

Natural Gas Consumption (GJ) 2,227 1,473 1,473 1,456

Natural Gas Cost $22,383 $15,194 $15,194 15,028

Propane Consumption (L) 88,006

Propane Cost $52,469

Total Energy Consumption (Mbtu) 3,057 2,414 2,414 2,400 3,056

Total Energy Cost $49,336 $44,326 $44,326 44,225 $79,423

Energy Cost Savings $5,010 $5,010 5,111

Additional Capital Cost $13,000 $48,750 35,000


Chabot Profitability Index 4.09 0.73 1.22

Annual GHG Emissions (tonnes CO2e) 119 81.5 81.5 80.7 142.8


Potential Annual GHG Offset Value ($25/tonne CO2e) $935.46 $935.46 955.76

Documents

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