Ground Source Heat Pump (GHP) Technologies in Residential Construction Josh White.

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Ground Source Heat Pump (GHP) Technologies in Residential Construction Josh White

Transcript of Ground Source Heat Pump (GHP) Technologies in Residential Construction Josh White.

Page 1: Ground Source Heat Pump (GHP) Technologies in Residential Construction Josh White.

Ground Source Heat Pump (GHP) Technologies in Residential Construction

Josh White

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Impetus

• 41% of U.S. energy consumption in 2014 came from residential heating and cooling.

(U.S. Energy Information Administration, April 2015)

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Energy Production

Retrieved from http://www.eia.gov

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“Geothermal” Pumps

• Low Grade-Refers to extraction of energy as a result of stored solar radiation.

• High Grade-Refers to energy that comes from pressurized water in the Earth’s crust.

(2014) Geothermal Heating and Cooling Systems. International School of Well Drilling

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Regional Temperature Variation (Annually)

http://www.physicalgeography.net/fundamentals/7l.html

-Relatively large daily and annual surface temperature variation based on incident solar radiation at a given latitude

45o N

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Ground Temperature Variation (by Latitude and Depth)

Mean annual earth temperature observations at individual stations, superimposed on well-water temperature contours.

http://www.builditsolar.com/Projects/Cooling/EarthTemperatures.htm

Le Feuvre 2007

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Anatomy of a GHP

Source: Chewonki.org

Vapor Compression Cycle

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Reverse Rankine or Refrigeration Cycle

Source: Chewonki.org

ffden-2.phys.uaf.edu/212_spring2007.web.dir

Drives phase change of refrigerant, liquid to gas and back.

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Coefficient of Performance

COP = Q/W

Expresses the efficiency of a heat pump as the ratio of the heat extracted from the pump to the work done by the compressor.

Ex. ΔT= (T1 – T2) = 31oC Where T2 = 6oC or 279K

COP = T1 / ΔT = 10! (Ideal case)

Actual values on the order of 3-5

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Direct vs. Indirect Systems

• Direct systems pump working fluid into boreholes and allow heat transfer between sink and fluid directly

• Indirect systems utilize a circulating fluid (separate from the working fluid) is used as an intermediary for heat transfer.

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Case Study #1: Z-Homes

2011 in Issaquah, WA

•10 Units

•“Zero net energy use”

•Zero Carbon Emissions

•Use of photovoltaics and GHP

Liljequist B. 2011

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Z-Home GHP

•15- 220ft Boreholes

•1” Diameter U-shaped pipes grouted and fused to a network just below the surface

•Pipes constructed of high density polyethylene (same as for natural gas)

•Pumping fluid is a water/ethanol mixture

Liljequist B. 2011

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PipingOne of the polyethylene pipes

Difficult ground conditions meant 10 weeks of drilling!

Subsurface networks of transfer pipes

Liljequist B. 2011

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GHP Well field Rig

Liljequist B. 2011

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Heat Pump

• Product of WaterfurnaceTM

• 1.5 Tons

• COP Range 3.1 to 4.0

• Cost: $3000-$8000

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Efficiency

Waterfurnace Product Manual

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Working Fluid

• R-410-A Refrigerant

• Alternative to Freon and other CFC’s

• Requires low boiling point

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Case Study #2- Direct Expansion Heating (China)

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Anatomy of a GHP

Source: Chewonki.org

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Comparison to Coupled GHP

Drawbacks• Requires more working fluid• More prone to leaks• Copper pipe vs polyethylene

Benefits• Less well piping• Less expensive long term

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Cost Comparison

Assumed for 90 day cooling and 140 day heating

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Conclusions

• Expense limits use in residential construction to commercial builders/ higher budget projects

• Feasible solely based on size, performance, and annual operating costs

• Subsidies can help expedite proliferation of the product

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ReferencesAndrews, J. & Jelley, N. (2013). Energy Science. Oxford University Press. Oxford, UK.

(Used as Background Only) Brown, J. (2015). A Crash Course in Geothermal Heat Pumps. Nordic Heating and Cooling.

Retrieved from http://www.nordicghp.com on 5/1/2015. Caird, S. & Roy, R. (2010). Adoption and Use of Household Microgeneration Heat Technologies. Low Carbon Economy, vol. 1, pp. 61-70. Gao, Y. et al. (2013). Comprehensive Benefit Analysis of Direct Expansion Ground Source Heat Pump System. Energy and Power Engineering, vol. 5, pp. 76-81. Liljequist, B. (2011). A Zero Energy Community. Dwell, September 14. Retrieved from: www.dwell.com/renovation/article/zero-energy-community-part-1 on 4/10/2015. Smith, M. (1974). Geothermal Power. AIP Conference Proceedings, 19, 401.

Uncredited (2014) Geothermal Heating and Cooling Systems. International School of Well Drilling; Lakeland, Fl.

Direct Correspondence with City of Issaquah and RH2 Engineering