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Geoexchange/District Energy Integration The University of British Columbia, Okanagan Campus – Kelowna, BC
Campus Location Plan – Okanagan Valley
UBCO District Energy System - Context
Summers are short, hot & arid
Winters are short & relatively mild
Spring & Fall are lengthy with wide swings in daytime/nighttime temperatures
New Academic Building Stock HVAC systems are 100% heat pump based, integrating 3 Data Centres, walk-in freezers/coolers etc.
Existing Academic Building Stock is relatively new:
• IE: all less than 22 years old, all hot water/chilled water, offering good opportunities to partially convert to heat pumps
Original Geoexchange System was a conventional pump & drain Open Loop Groundwater Based System
Thus, many opportunities for Energy Sharing….
Original Open Loop Configuration
Facilities Served
• Arts • Sciences • Admin • Student Centre • Fine Arts • Library • Health Sciences • Fipke Centre • Arts/Sciences • Eng/Mgmt/Educ.
(80,664 m2)
Groundwater @ 12.3°C Pumped Directly to Facilities 24/7
Groundwater Returned to the Earth cooler, warmer, or sometimes with no temperature change at all
Injection Well
Supply Well
Geoexchange/District Energy Development History
• 3 Phases of Construction
• 9 years of project development history
• 2004 Water required for Trout Research Program
• 2004 Well drilled to 750’ deep, DRY, near Science Bldg
• 2004 Other wells drilled, potential of 1,200 USGPM each
• 2005 Trout Lab water well not needed, Geoexchange potential recognized
• 2006 – 2008 Design/Install of Open Loop Geoexchange
• 2008 – Oct 2011 Open Loop operates
• 2010/2011 Feasibility Study/Design/Construction of hybridized Open Loop/Closed Loop District Energy System
• 2011 October – Present
- Operation as Hybridized Open/Closed Loop, DISTRICT ENERGY SYSTEM
UBCO District Energy System
DES Supply
DES Return
Bldg. Link
HX
Building Loop
Balance DES
Return
HP
HP
HP
DES
Supply
Control Valve
Water Source
Heat Pumps
To Terminal Devices
HWS
CHWS
To Other Buildings
Building Energy Loop Shade Sun
Geoexchange Infrastructure
38,000 tonnes of estimated GHG emissions saved over 25 year period, equivalent to 3,500 vehicles removed from roads
$14 million total project cost over 3 phases
$2.9 million Provincial & Federal K.I.P. grant for Phase 2
3,200 USGPM licensed peak groundwater pumping rate
Awards:
- $57,106 FortisBC electrical utility grant
- $41,000 FortisBC Gas condensing boiler rebate
- Featured on local Television News
- Believed to be the first of its kind/largest
Technology is scalable and portable to other campuses
Approval of the system given by nearby water utility
Groundwater components constructed to drinking water standard
Monitored and tested continually to ensure compliance with groundwater standards and Ministry of Environment “Environmental Assessment Office” or EAO
5 km2 Aquifer, 60m thick
Fine-grained sand and gravel, basically in a gravel pit pit
Surrounded on 3 sides by rock, appendage to valley
Relatively very flat gradient – low recharge from precip
Flow direction from north to south
Limited use by others for water supply (GEID)
Down-gradient of industrial area in old (unused) part of pit
Hydraulically isolated from creeks to east in Valley
Geology of the Source Aquifer
Geology of the Source Aquifer
Maximize screen intake vs. available drawdown (trade off)
Aquifer thickness and gradation control screen design
Optimize screen capacity (40 to 60 % of aquifer material retained)
Maximize
Available
Drawdown
Maximize
Screen
Length
vs
Extraction Well Design
Injection Well Design
Maximize screen length
Well screen “development” critical
Down hole flow control valves to create system pressure and prevent air entrainment during injection
Aquifer chemistry – encrustation and bio-fouling potential
Generally design for 2 times more injection capacity than extraction capacity
Flow
Positioning of extraction and Injection wells Critical
Separation distance and
pumping rates are
critical to minimize
potential for thermal
short-circuiting
Drawdown: during summer months while GEID pumping 2 wells
Groundwater Modeling to assess potential impacts
Groundwater Modeling to assess potential impacts
Drawdown: during winter months while GEID pumping only one well at lower rate
Groundwater Modeling to assess potential impacts
Thermal: Maximum temperatures during summer months while rejecting heat
Groundwater Modeling to assess potential impacts
Thermal: Minimum temperatures during winter summer months while extracting heat
Contingency, Redundancy, Monitoring and Adaptive Management
Additional injection wells
Contingency injection field
Temperature and chemistry monitoring
Sharing of data with GEID
Pumped / injected volumes lower than anticipated with district system
Delta T less with district system
Reasons for Geo-Ex and District Energy System
UBCO Academic & Admin Facilities were known to have differing heating/cooling profiles; some could reject surplus heat energy while outside temperatures were as low as -2°C. Others could utilize this rejected energy, as their heating demand would begin at outside temperatures of +15°C.
UBCO / UBC has set aggressive GHG reduction targets, to exceed Kyoto Protocol requirements.
• By 2015: Reduce GHG emissions to 67% of 2007 levels
• By 2020: Reduce GHG’s to 33% of 2007 levels
• By 2050: Eliminate GHG’s and become a net positive energy producer
Recapture of waste heat was therefore desired, to further reduce harmful GHG emissions from natural gas fired building heating systems.
Buildings that reject energy can feed the surplus energy to other facilities that require it; as long as all facilities are grouped together in an Energy Sharing Closed Energy Loop format.
Reduction of aquifer peak and monthly demand made possible by Closed Loop
Centralization of heat exchanger maintenance was required; to reduce ongoing cost and complexity, and to increase system reliability.
Adaptation to future low temperature energy sources was desired, therefore an ambient-temperature ENERGY SHARING District Energy System was created.
District Energy Control Facility
Groundwater - Off
Campus Energy Share
Ring
8.9°C - 23.9°C 8.9°C - 23.9°C Fluid Coolers - Off
Groundwater - Off
Facilities Served
• Arts • Sciences • Admin • Student Centre • Fine Arts • Library • Health Sciences • Fipke Centre • Fitness • Arts/Sciences • Eng/Mgmt/Educ.
(81,864 m2)
Campus Mode -
Balanced
Boiler - Off
Thermal Storage
Daily Average System
Load (%)
System Load
(mbtu/hr)
Storage Amount
(btu)
Storage Capacity
(hrs)
Daily Storage Capacity
(hrs)
Annual Hours
0-12.5 2,250 13,500,000 5 10 ~2,000
25 5,500 13,500,000 2.5 5 ~700
50 11,000 13,500,000
1.25 2.5 ~3,800
>50 >11,000 nil nil nil ~2,260
Total 8,760
Energy Balance – 9:03am Oct 12, 2012
Energy Sharing at Work – 9:03am Oct 12, 2012
UBCO's Aggressive Greenhouse Gas Plan
96% of GHG Emissions are from Buildings (Heating & Electricity)
Reducing Heating GHG’s & Energy Cost
Competing Technologies
Heating Output
Input Energy Req’d
Earth Energy Input
CO2 (greenhouse gas) Output
Energy Cost
1) Natural Gas Fired Boiler
1 GJ 1.25 GJ (gas) Φ 62.7 kg $11.38 (1)
2) Water to Water Heat
Pump
1 GJ 0.29 GJ (electricity)
0.71 GJ
0.033 kg (0.05% of
Natural Gas)
$5.92 (2)
Notes: 1) Based on UBCO’s natural gas cost of $9.11/GJ including taxes. 2) Based on FortisBC electricity cost of $0.07350/kW*hr including taxes.
GHG Reductions - Results
UBC Okanagan Campus
GHG Emissions / square meter
Year Buildings
(m2) tCO2e Efficiency
(tCO2e/m2)
Efficiency Improvement vs.
2007 Baseline
2007 71,919 2,186 0.0304 -
2008 79,100 2,412 0.0305 -
2009 (1) 97,900 2,825 0.0289 5%
2010 110,844 2,726 0.0246 19%
2011 139,200 3,135 0.0225 26%
2012 140,400 3,204 (2) 0.0228 (2) 25% (2)
Notes: 1) 2009 was the first full year of operation with the Geoexchange based Fipke Centre. 2) Predicted tCO2e emissions based on recent Carbon Reduction Study and two quarters of utility data.
Renewable District Heating Energy
80% of Heating Sources are from Renewable Energy!
Better Together? – District Energy & Geoexchange
Provides Energy Security and choice of cheapest heat source through switching between gas heat, and electric heat pumps, if required
50%+ of heating energy comes from renewable earth energy, plus 20% from hydro power – both are perpetually renewable
Plastic un-insulated pipelines are lower cost and simpler to install/maintain than steel
Hybridized approach utilizes conventional boilers and evaporative coolers for peak loads, providing redundancies and reducing capital required for water wells
Large reduction in groundwater usage; lowers cost of maintenance, extends lifespan
Heat exchanger and most Maintenance is centralized
Controls growth of campus CO2 emissions:
** Estimated 38,000 tonnes of CO2 reduction over 25 years
** Has slowed CO2 emission growth despite rapid campus expansion program
Operating cost savings can be realized over long term
Scalable for future expansion
Recycles waste energy on-site, eliminates “once-through” energy loops
Heating energy can be supplemented by any waste heat source, biomass, biogas etc.
Policy – The Burning Questions
Where are Gas and Electricity Prices going?
Cap and Trade System for Alberta (maybe all of Canada?) imposed by America in exchange for Keystone XL Pipelineb?
Are facilities readily upgradeable for a legislated low carbon system?
Are designers ready for design of heat pump systems?
Are owners and government prepared for the extra capital investment required for low carbon heating?
Question Period
Remi Allard, M. Eng., P. Eng. – Senior Hydrogeologist
Piteau Associates Engineering Ltd.
#304 – 1912 Enterprise Way
Kelowna, BC V1Y 9S9 Tel: (778) 484-1777
George Hutchison, AScT. - Mechanical Team Lead
Williams Engineering Canada Inc.
#304 – 1912 Enterprise Way
Kelowna, BC V1Y 9S9 Tel: (778) 484-2984
