Geothermal Heating and Cooling: Digging Deeper for Energy ...€¦ · Geothermal Heating and Cooling: Digging Deeper for Energy Savings Geothermal Heating and Cooling: K-12 Applications

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Geothermal Heating and Cooling: Digging Deeper for

Energy Savings

Presented by Illinois ASBO Professional DevelopmentMonday, November 3, 2014

Geothermal Heating and Cooling: Digging Deeper for Energy Savings

�Presenters:

Ron DeGeorge, Buildings & Grounds Director, Prospect Heights SD 23Luann Kolstad, Business Manager, Prospect Heights SD 23Paul Reitz, PE, CEM, CBCP, Energy Solutions Engineer 360 Energy GroupMike Stanch, Energy Solutions Manager, 360 Energy Group

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What is Geothermal Heating & Cooling?

• The temperature below the surface of the Earth remains constant (~55F), regardless of weather patterns throughout the year.

• In warmer months, heat is rejected from the building to the ground.

• In colder months, heat is reclaimed and added to the building to serve the buildings heating needs.


What makes ground source systems efficient?

•Energy recycling- In moderate climates, heat removed from the building in warmer months

can be reclaimed and used to heat the building in colder months.•Heat recovery

- The connecting energy loop in the building allows for energy recovery- Where one space is in heating another is in cooling , this allows spaces to

“Share” Energy- Variances in occupant comfort requirements can be met efficient by

transferring heat from on room or zone to another.•Low supporting system power requirements

- Fluid circulation energy is very low with well designed systems.•Geothermal Heat Pumps are >4X as efficient as fossil fuels for heating applications!

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How Heat Pumps Work

3-4 kW of Energy moved from the Earth

4-5 kW Heat Delivered

1 kW electricity


Mechanical system selection

- Provide an economic evaluation of prospective systems- Look at energy efficiency- Look at system maintenance/complexity- First Cost and Life Cycle Cost of the potential solutions

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Mechanical System Considerations

• Ground source - No exposed equipment- Simple system- Easy to maintain- Energy efficient- Lowest life cycle cost- Tax / depreciation advantages- Utility support considerations- No gas required

• Traditional systems VAV and Single Zone- Exposed condensing units on ground or roof- Digital controls required for VAV- Electric reheat or hydronic heating and cooling- Maintenance is done by a more qualified individual- Higher life cycle cost- Higher operating cost- Gas may be required


Achieving High Performance

Not all ground source systems are created equally. Experience matters….

- Understanding how building energy is moved throughout the system- Ground loop design- Building system optimization- Understanding project budget

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The Ground Loop• A series of piping tied together to

make a heat exchanger.• Can be configured as vertical bore

or horizontal.• Can be placed in the ground or in a

body of water.• Open loop systems, also known as

pump and dump systems, circulate ground water and dump to another body of water.


Ground Loop Configurations

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Geothermal Heating and Cooling: K-12 Applications

• Saving heating and cooling energy– Typically 50% lower energy consumption vs.

conventional heating and cooling systems• Geothermal provides heating and cooling in one

combined system• Reduced maintenance costs

– Heat pumps and compressors are robust– Typically just a filter replacement is required

• Be green AND minimize budget impacts of variable weather patterns and changing utility costs!

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Geothermal Heating and Cooling: K-12 Applications

HVAC Systems that Enhance Learning• Reduced noise levels• Temperature and humidity can be

adjusted room by room to maintain desired conditions of specific occupants

• Indoor Air Quality easier to control• Ventilation can be controlled “on

demand”

• Overall adaptable to changing education environments


Geothermal Pros:• 50% or more reduction in

energy usage vs. conventional systems

• Lower maintenance costs• Enhanced comfort and

teaching environment• Don’t need advanced

controls for optimal operation and efficiency of geothermal systems

Geothermal Cons:• Higher initial costs

associated with installation• More complicated than

conventional HVAC system – requires more time for planning and analysis up front

• Lack of space for Ground Loop or lack of optimal soil conditions

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Selecting a Geothermal Design Professional

• Your system should not be the First • Engineer should characterize the load

- Cooling Dominated, Heating Dominated or Balanced• Knows the limitations presented by your Site

- Drilling conditions- Thermal Conductivity

• Design Implementation - Ability to compare multiple systems to best fit the application

Distributed heat pumpsVAV systemVariable Refrigerant flow


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After


• In 2007, legislation amended the Illinois Public Utilities Act • Required the State’s largest utilities and the Department of Commerce &

Economic Opportunity (DCEO) to develop a portfolio of electric energy efficiency programs to reduce energy demand.

• In 2009, legislation was passed to include natural gas energy efficiency programs

• Illinois Energy Now (IEN) is the portfolio of programs the DCEO offers to administer the electric and natural gas incentives for the public sector

• 2013-2014 Public Sector Energy Efficiency Programs • combine electric and natural gas incentives

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• Illinois Department of Commerce and Economic Opportunity (DCEO) – Illinois Energy Now– Provides funds for projects participating in the

Caucus’ Public Sector Energy Efficiency Program– Sets program terms, reimbursement rates and

performance standards– Funds other supportive services like Smart Energy

Design Assistance Center (SEDAC) and Trade Ally’s Program


• The Metropolitan Mayors Caucus - project administrator– Manages DCEO funds, partners with 360 Energy Group– Serves as an ‘aggregator’ of local projects for DCEO Illinois

Energy Now program

• 360 Energy Group - energy efficiency consultants– Manages compliance with DCEO program for the Caucus– Provides technical assistance to municipalities and other public

sector applicants

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• Illinois Energy Now- began June 1, 2014

• Incentives available until May, 2015• 2014-2015 Program Year- $70 million

available for incentives and other related programs


GSHP - DCEO Incentive Calculation

• DCEO offers a Custom Incentive of $3.00/therm saved and $0.12/kWh of electricity saved.

• Due to Energy Efficiency Program regulations, Natural Gas Savings must be adjusted according to DCEO approved guidance, to account for additional electricity used by Heat Pumps in heating mode.

• Generally, existing system efficiencies can be used as a baseline for calculating energy savings.

• If no existing system exists (ie: Air Conditioning is being added), the governing energy code, IECC 2012, must be used as a baseline for energy savings calculation.

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GSHP – Heating Energy Savings• If Existing heating system is a Natural

Gas fired Hot Water Boiler:- Baseline Efficiency = Existing Boiler Efficiency (~70-80% or as determined)- Code Efficiency = IECC 2012 Code Minimum Heat Pump (COP = 3.1)- Proposed Efficiency = Actual Efficiency of Installed Heat Pump (ie: COP = 4.2)


GSHP – Heating Energy Savings- Therm Savings = (Therm Savings from Removing Boiler) – (Therm equivalent of electric energy consumed by GSHP at code efficiency).- kWh Savings (heating mode) = (kWh consumed at proposed efficiency) –(kWh consumed at IECC 2012 code ASHP minimum efficiency)

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GSHP – Cooling Energy Savings

• If existing cooling system is present:- Baseline Efficiency = Existing efficiency of cooling system (ie: EER = 8)- Proposed Efficiency = Actual efficiency of Heat Pump (ie: EER = 18)- kWh Savings (cooling mode) = (kWh consumed at proposed efficiency) –(kWh consumed at existing baseline efficiency)


GSHP – Cooling Energy Savings

• If no existing cooling system exists, compare to a hypothetical baseline:

- Baseline Efficiency = IECC 2012 code minimum efficiency (EER = 9.5)- Proposed Efficiency = Actual efficiency of Heat Pump (ie: EER = 18)- kWh Savings (cooling mode) = (kWh consumed at proposed efficiency) – (kWh consumed at IECC 2012 code minimum baseline efficiency)

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MacArthur Middle School Analysis

• Existing heating system was a 80% efficient Natural Gas fired boiler plant.• No existing cooling system was present. Therefore a IECC 2012 code

minimum baseline efficiency was used (COP = 3.1).


MacArthur Middle School DCEO Incentives

• kWh Savings: 177,000/yr• therm Savings (after discount): 28,497/yr• Dollar Savings: $22,919/yr (Based on Actual Costs)• ComEd Electric Incentive (kWh Savings): $23,364• Nicor Natural Gas Incentive (therm Savings): $94,041• Total DCEO Incentive: $117,405• Incremental Cost of Geothermal Heat Pump System compared to

Conventional Boiler/Chiller System: $350,000• ICECF Grant: $75,000• Incremental Simple Payback w/ DCEO and ICECF Assistance: 6.8 years

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Who We Are•Elementary School District:

- Serving 1500 students- Two Campuses- Five Buildings:

1 Middle School (Main Campus) 6th – 8th Grades1 Grade School (Second Campus) Pre-K – 1st Grades1 Grade School (Main Campus) 2nd – 3rd Grades1 Grade School (Main Campus)4th – 5th Grades1 Administration Building (Main Campus)


In the Beginning…..District faced with Deferred Replacement of Mechanicals in all Buildings:

• Obsolete Unit Ventilators and Controls• Boilers at end-of-life and beyond• AHU at end-of-life and beyond• Existing HVAC Systems in locations where A/C was all

reaching end-of-life• 3 Schools – No Air Conditioning except offices.

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At a Cost of…..•$5,145,875 - Replacement of only Priority Mechanical Items.•Priority Maintenance Items Account for only ½ of Necessary Mechanical Replacements!•Cost does not include adding air conditioning.•$3,629,000 – Estimate from 2008 to add air conditioning to three buildings. •$8,774,875 – Total for both.


Now What do we Do?• If we decide that students really do not need air

conditioning, after all we all suffered in classes of 40 students after walking to school barefoot, uphill both ways!

• Then our total cost before architectural fees, etc. is $5,145,875.

• But, this only fixes half of our priority maintenance items!

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Looking at Other Options…..•Geothermal heating and cooling is that an option?•But….

- It is too expensive!- Are you fracking!- Are you going to cause an earthquake!- What about my drinking water – are you polluting it?- Will there even be any water left to drink!- Are you heating up the earth’s core?


The Answer…..•$6,203,064 Estimated Total Cost before architectural fees of Geothermal Heating & Cooling in Four Schools.•Project will result in replacement of ALL mechanical systems in four schools.•Minimal maintenance for at least 20 years!•Domestic Hot Water Heaters are only use of Natural Gas = Decreased Gas Bill!

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Here we Go!Summer 2013:

• MacArthur Middle School Converted to Geothermal Heating & Cooling

• Two Well Fields Drilled: - Central Campus field 120 bore holes at a depth of 500 feet. Sized to serve middle school, two grade schools and administration building.- Eisenhower Campus 32 bore holes at a depth of 500 feet.- **We call it “Bore Holes” instead of “Wells”**


First Winter Results

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In Graphic Form

February 2014 Usage ComparisonMacArthur MS: 110,000 sf used only 352 thermsMy Humble Home of 2,900 sf used 254 therms


Geothermal Drilling• Will drill 7000 feet/week dependent on conditions. • Bore holes are 5 inch in diameter. • MacArthur: 120 bore holes at a depth of 500 feet• Eisenhower School: 32 bore holes at a depth of 500

feet.• There will be some pounding noise associated with

drilling as drills go through rock

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Bore field location for 3 facilities


Geothermal Drilling• Piping: Piping installed in bore holes is a closed loop system.

Piping material is a high density polyethylene material designed for geo applications. Material carries 50 year warranty. Think yellow natural gas pipe.

• Solution flowing through pipes: 80-85% water, 15-20% food grade propylene glycol

• Project overseen by IGSHPA (International Ground Source Heat Pump Association), NGWA (National Ground Water Association) and IDPH (Illinois Department of Public Health).

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Unforeseen IssuesRetraining of Personnel

• No Open Windows or Doors• Individual T-Stat Control – Heating/Cooling• Fresh Air Based on CO-2 Level• No Setbacks – System Runs 24/7• No Programming for Special Events

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Retrain Your Brain

• Old Thought: Economize and use Outside Air to Heat or Cool.

• New Thinking: Does Not Apply to Geothermal!– Need to Put Heat/Cooling Back into the Earth– Really Do Not Want Unconditioned Air!

Building EnvelopeHumidity Issues

• Negative Air: Building was never affected by being in negative air pressure before.

• Sweating of Pipes on Start-Up/Humid Days

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Humidity Solutions!• Added Make-Up Air Unit in Kitchen• Balanced Exhaust Fans• Tightened Up Building Envelope • Insulated Geothermal Pipes• Automation Controls

Drum Roll Please…..• IT WORKS!!!!

– Last Winter During Polar Vortex No Problems!– Polar Vortex Occurred Before Glycol was

added.– No Boilers!!! Natural Gas Savings!– Quiet Classrooms– Heat/Cool at the Same Time!– Low Maintenance

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Questions?

Documents

Geothermal Heating and Cooling: Digging Deeper for Energy ...€¦ · Geothermal Heating and Cooling: Digging Deeper for Energy Savings Geothermal Heating and Cooling: K-12 Applications