So called global warming is just a secret plot by wacko tree huggers to make America energy independent, clean our air and water, improve the fuel efficiency of our vehicles, kick start 21st century industries and make our cities safer and more livable. Don’t let them get away with it.
Chip Giller, Grist.Org
Geothermal Systemsfor
Commercial Buildings
Geothermal Systemsfor
Commercial Buildings
Presenters:
Brian Smith, PE, LEED APPrincipal, Allied Consulting Engineering Services
Steve Sakakeeny, CPG, LSP, CHMM Principal, SAK Environmental
D.J. Quagliaroli President, DRAGIN Geothermal Well Drilling
Allied Consulting Engineering Services, Inc. is a Registered Provider with the American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-AIA members are available on request.
This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing an any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
Copyright Materials
This presentation is protected by US and International copyrightlaws. Reproduction, distribution, display and use of the presentation without written permission of the speaker is prohibited.
©2009 Allied Consulting Engineering Services, Inc.
consulting engineering services, inc.
Develop an understanding of how a geothermal heat pump system operates.Have the ability to assess if a building is a candidate for a geothermal heat pump system, including technical and regulatory obstacles.Understand the environmental, operational and cost benefits of a geothermal heat pump system.
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Loops are installed in trenches 5-10 feet below surface.
Requires 2,500 square feet per ton of cooling.
Generally installed in areas with moist sand or dirt.
Must understand hydrology.
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Boreholes are drilled several hundred feet deep.
Requires 200-250 linear feet per ton of cooling.
Geothermal loop is installed directly into a pond or other body of water near the building.
Size and depth of pond must be analyzed to ensure sufficient capacity.
Man made ponds/lakes are often installed to accommodate a pond loop simultaneously adding to the aesthetics of the property.
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Wells are drilled 1,000 – 1,500 feet deep.
Generally installed in areas with shallow bedrock (within 200’)
Heat transfer medium (water) comes into direct contact with heat sink/source (rock), resulting in higher efficiency than closed systems.
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From a higher temperature to a lower temperature
Heat flows downhill
Let’s take 1 pound of water at 80°F and heat it to 90°F by adding 10 BTU
10 BTU
Now let’s take 1 pound of water at 90°F and let it cool to 80°F and give up 10 BTU
10 BTU
What if we could cool 1 pound of water from 50°F to 40°F?
Heat
We would get 10 BTU.
10 BTU
What happens when we put heat into water at 212°F ?
Heat
Everyone knows Water boils at 212°F.
It takes 970 BTU to change 1 pound of water at 212°F to 1 pound of steam at 212°F.
970 BTU
In Denver, Colorado, water boils at 202°F.
In the olden days, before microwave ovens,
folks used a Pressure Cooker to cook foods faster.
Water boils at 240 °F at 10 PSIG
250 °F at 15 PSIG
In the classic high school physics experiment water can be made to boil at any temperature by reducing the pressure.
This concept is the basis of modern air conditioning.
Except air conditioners don’t use water they use Halogenated Chloro Fluoro Carbons like Chlorodifluoromethane and Zeotropic blends of Fluorinated Halocarbons like difluoromethane and pentafluoroethane.
40.00 83.255
40.00 83.255 21.662 108.31321.662 108.313
120.00 274.65
120.00 274.65
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21.662 108.31321.662 108.313
45.952 112.914
45.952 112.914
What are the
benefits?
Geothermalvs.
Conventional
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Boilers
Smoke Stack
Water Chillers
Earth Shaker 2000
Cooling Towers
Legionnella
Project Example: Zero Arrow Street
Zero Arrow Street, Cambridge, Massachusetts
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40,000 Square Feet
Mixed Use: Office/Black Box Theater (American Repertory Theater)
Urban Setting
Heated and Cooled with Three 1,500 Foot Standing Column Wells
LEED Certified
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FIRST COSTS OF EACH SYSTEM TYPE
Ground Source Heat Pump (GSHP):
Wells = 3 x $55,000 = $165,000
Water Source Heat Pump (WSGP):
Cooling Tower = $30,000
Boiler = $12,000
Cost Difference:$165,000 – ($30,000+$12,000) = $123,000
Other components are approximately equal for both systems (i.e. heat pumps, ductwork, piping)
Annual Energy Costs
Budget Building Design
$12,653.39$16,982.00$4,510.36$326.81$19,697.56$9,955.92Annual Costs
$1.90$1.90$1.90$1.90$1.90$1.90Cost $/Therm
$0.180$0.180$0.180$0.180$0.180$0.180Cost $/KWhr
87130Therms
70,29894,34425,0581,81622,19355,311kWh
Domestic Water
Interior Lighting
PumpsInteriorVentilation
HeatingCooling
TOTAL $64,978.23
Annual Energy Costs
Proposed Design
$12,653.39$16,982.00$4,290.12$106.95$10,547.91$9,017.39Annual Costs
$1.90$1.90$1.90$1.90$1.90$1.90Cost $/Therm
$0.180$0.180$0.180$0.180$0.180$0.180Cost $/KWhr
000Therms
70,29894,34423,83459431,47650,097kWh
Domestic Water
Interior Lighting
PumpsInteriorVentilation
HeatingCooling
TOTAL $48,715.67
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Energy Savings
WSHP Cooling $9,956WSHP Heating $19,698WSHP Total $29,654
GSHP Cooling $9,017GSHP Heating $10,548GSHP Total $19,565
Geothermal Heat Pump Savings:$29,654 - $19,565 = $10,089
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Simple Payback
System Cost Differential $123,000
Geothermal Heat Pump Savings $10,088
Payback = $123,000 ÷ $10,000/yr. = 12.2 years
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Water Source Heat PumpCooling tower water treatment
Cooling tower fan belts
Outdoor piping (roof) exposed to weather
Cooling tower exposed to weather
VFD’s can be fussy (control of CT fans)
Boiler service (mandatory once/year)
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Ground Source Heat PumpBuilding loop water treatment/test and add
chemicals if necessary
Other components (i.e. heat pumps and water pumps) require equal maintenance for both systems
Geothermal Benefits
Free heatNo fossil fuel hazardsReduced carbon footprintEnhanced serviceabilityNo outdoor noiseNo visual impact outdoorsPositive cashflow day oneSavings increase overtime10% Tax Credit (30% Residential)
GeologyAquifer testing (hydraulic and thermal)Well designConstruction inspectionWater quality considerationsRegulatory permits
Certified Professional Geologists,Hydrogeologists, Chemists
Water circulation in 1 well
800 ft. to 1,500 ft. deep
Surface bleed for thermal balance
Gravity injection
Permitting
Standing Column Well
Designing to the EnvironmentYOUR ANSWERS ARE UNDERGROUND!
Geology affects thermal capacity of wellWater yield affects thermal capacity of wellWater quality affects:
Corrosion ratesO&MRegulatory considerations
Aquifer Characteristics
Water yield
Rock density
Thermal conductivity testing – Btu/ft-hr oF
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Brackish water –corrosion and water management
Collapsing bore holeWaste management Boston Groundwater Trust (Back
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Regulatory Permitting: Applicable Rules
Underground Injection (UIC) Control ProgramGroundwater discharge Permit Program (314 CMR 5.00)
MADEP Guidelines for Ground Source Heat Pump Wells, February 2009
Regulatory Concerns
Data base of injection wells
Thermal pollution
Cross-contamination of aquifers
Registration under the UIC Program
Initial registration
Significant system modifications
Change in ownership
Well closure
Water Quality Testing
Required for all open loop wells
“Conditional” to “Full” registration
Exceedance may require water treatment
Copper and Lead on return flow
CURRENT
REQUIREMENTS
Other permitting requirements:
Bleed water to dry well –UIC registration
Bleed water to sewer or storm drain – local permit
Bleed water to surface water –not allowed until Massachusetts
federal EPA permit renewed
CURRENT
REQUIREMENTS
Treatment and expanded permitting required if:
Water quality limits exceeded, or
Using treatment chemicals (i.e. disinfectants, scale inhibitors)
Questions?Thank you for your time.
This concludes the American Institute of Architects Continuing Education Systems Program.
Allied Consulting Engineering Services215 Boston Post Road Sudbury, Massachusetts43 Jefferson Boulevard Warwick, Rhode Island
978-443-7888 alliedconsulting.net
consulting engineering services, inc.
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