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Photo Credit: Geothermal Heat Pump Consortium (NREL PIX) Clean Energy Project Analysis Course Ground-Source Heat Pump Project Analysis © Minister of Natural.

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Presentation on theme: "Photo Credit: Geothermal Heat Pump Consortium (NREL PIX) Clean Energy Project Analysis Course Ground-Source Heat Pump Project Analysis © Minister of Natural."— Presentation transcript:

1 Photo Credit: Geothermal Heat Pump Consortium (NREL PIX) Clean Energy Project Analysis Course Ground-Source Heat Pump Project Analysis © Minister of Natural Resources Canada 2001 – Philadelphia Enterprise Centre, USA – 28 GSHPs for Heating and Cooling

2 © Minister of Natural Resources Canada 2001 – Objectives Review basics of Ground-Source Heat Pump (GSHP) systems Review basics of Ground-Source Heat Pump (GSHP) systems Illustrate key considerations for GSHP project analysis Illustrate key considerations for GSHP project analysis Introduce RETScreen ® GSHP Project Model Introduce RETScreen ® GSHP Project Model

3 © Minister of Natural Resources Canada 2001 – Heating Heating Cooling Cooling Hot water Hot water Sound permafrost foundations Sound permafrost foundations …but also…  Efficiency  Decreased maintenance  Decreased space needs  Low operating costs What do GSHP systems provide?  Stable capacity  Comfort & air quality  Reduced peak electrical loads for air conditioning Photo Credit: Solar Design Associates (NREL PIX) Impact 2000 Home, Massachusetts, USA Residential Heat Pump

4 © Minister of Natural Resources Canada 2001 – Earth connection  Ground-coupled  Groundwater  Surface water 2. Liquid-source heat pump 3. Interior heating/ cooling distribution subsystem  Conventional ductwork Components of GSHP Systems 1 2 3

5 © Minister of Natural Resources Canada 2001 – Liquid-Source Heat Pump Water-to-air heat pump Water-to-air heat pump Reverses direction Reverses direction 3.5 to 35 kW of cooling per unit 3.5 to 35 kW of cooling per unit Multiple units for big buildings Multiple units for big buildings Excess heat following compression provides hot water via desuperheater Excess heat following compression provides hot water via desuperheater

6 © Minister of Natural Resources Canada 2001 – Types of Earth Connection Vertical (GCHP)  Rocky ground  More expensive  Little land used  High efficiency Horizontal (GCHP)  Most land used  Less expensive  Small buildings  Temp. varies Groundwater (GWHP)  Aquifer+Injection  Least expensive  Regulations  Fouling Also surface water and standing column heat exchangers Also surface water and standing column heat exchangers

7 © Minister of Natural Resources Canada 2001 – GSHP Resource: Ground Temperatures Ground absorbs about half of sun’s incident energy Ground absorbs about half of sun’s incident energy Ground dampens temperature variation Ground dampens temperature variation  GSHP more efficient Temperature variation decreases with depth Temperature variation decreases with depth  Negligible below 15 m Local ground temperatures depend on climate, ground & snow cover, slope, soil properties, etc. Local ground temperatures depend on climate, ground & snow cover, slope, soil properties, etc. Graphic: Canadian Building Digest

8 © Minister of Natural Resources Canada 2001 – Examples of GSHP System Costs Utility subsidy to lower peak air conditioning loads Utility subsidy to lower peak air conditioning loads Photo Credit: Suomen Lämpöpumpputekniikka Oy Photo Credit: GeoExchange Consortium Rising energy costs Rising energy costs Environmental concerns Environmental concerns Air conditioning is bonus Air conditioning is bonus

9 © Minister of Natural Resources Canada 2001 – Ground-Source Heat Pump Project Considerations Most cost-effective when: Most cost-effective when:  Heating and cooling required  Large seasonal variations in temperature  New construction or HVAC replacement  For heating: low electricity costs and high gas & oil costs  For cooling: high electricity costs and peak load charges Availability of trenching and drilling equipment Availability of trenching and drilling equipment Uncertainty about cost of exchanger installation Uncertainty about cost of exchanger installation Customer’s criteria for cost-effective Customer’s criteria for cost-effective Photo Credit: Craig Miller Productions and DOE (NREL PIX) GSHP Installation Heat Exchanger Layout, Commercial Building

10 © Minister of Natural Resources Canada 2001 – Examples: Australia, Germany and Switzerland Residential Building Systems High-end homes High-end homes  Higher capital costs  Longer term view of cost-effective  Environmental or comfort benefits Utility incentive can be a significant factor Utility incentive can be a significant factor Photo Credit: Bundesverband WärmePumpe (BWP) e.V. Photo Credit: GeoExchange Consortium Photo Credit: Eberhard & Partner AG 20 kW Groundwater Heat Pump, Germany Drilling Rig for Vertical Boreholes, Swiss Residence 320 Apartments, South Australia

11 © Minister of Natural Resources Canada 2001 – Examples: UK and USA Commercial Building Systems Short payback periods often required (< 5 yrs) Short payback periods often required (< 5 yrs) Land availability may pose problems Land availability may pose problems Less internal space used Less internal space used Simple, distributed controls Simple, distributed controls Reduced vandalism risk Reduced vandalism risk Reduced peak load charges Reduced peak load charges Auxiliary heating not needed Auxiliary heating not needed Photo Credit: Groenholland B.V. Photo Credit: Marion Pinckley (NREL PIX)Photo Credit: International Ground Source Heat Pump Association Building Cluster, Kentucky, USA Filling Station, Kansas, USA Commercial Building, Croydon, UK

12 © Minister of Natural Resources Canada 2001 – Examples: Canada and USA Institutional Building Systems Longer paybacks accepted Longer paybacks accepted More open to innovative systems More open to innovative systems Simultaneous heating and cooling loads Simultaneous heating and cooling loads Photo Credit: Robert R. Jones/Oklahoma State University (NREL PIX) Trenching for Horizontal Exchanger School, Quebec, Canada Photo Credit: Natural Resources Canada

13 © Minister of Natural Resources Canada 2001 – RETScreen ® Ground-Source Heat Pump Project Model World-wide analysis of energy production, life-cycle costs and greenhouse gas emissions reductions World-wide analysis of energy production, life-cycle costs and greenhouse gas emissions reductions  Horizontal & vertical closed-loop  Groundwater open-loop  Residential, commercial, institutional & industrial Currently not covered: Currently not covered:  Surface water GSHPs  Long-term thermal imbalances in the ground  Simultaneous heating & cooling (block loads only)  Water heating

14 © Minister of Natural Resources Canada 2001 – See e-Textbook Clean Energy Project Analysis: RETScreen ® Engineering and Cases Ground Source Heat Pump Project Analysis Chapter RETScreen ® GSHP Energy Calculation

15 © Minister of Natural Resources Canada 2001 – Example Validation of the RETScreen ® GSHP Project Model Energy use compared for synthesized bins versus monitored data Energy use compared for synthesized bins versus monitored data GHX length compared to 6 sizing programs and detailed simulation program GHX length compared to 6 sizing programs and detailed simulation program -5%14124%16017%3440%14129%16029%344vs. Actual -12% -18% -2% 5% -19% -12% -6% -14% 2% 9% -11% -4% * 1 Year Design values used for RETScreen comparison vs. RETScreen Energy Use vs. RETScreen Descriptive Average for other software Commercial Nebraska Residence 2 Wisconsin Residence 1 Louisiana Commercial Nebraska Residence 2 Wisconsin Residence 1 Louisiana 10 Year Design*1 Year Design Program

16 © Minister of Natural Resources Canada 2001 – Conclusions GSHPs provide heating, cooling & hot water GSHPs provide heating, cooling & hot water Ground dampens temp. variations & leads to high GSHP efficiencies Ground dampens temp. variations & leads to high GSHP efficiencies GSHP initial costs are higher, but O&M costs are lower GSHP initial costs are higher, but O&M costs are lower  Climates requiring heating and cooling are most promising RETScreen estimates: RETScreen ® estimates:  Frequency distribution of outside temperature  Building loads as a function of outside temperature  Annual space heating and cooling energy benefits RETScreen ® is an annual analysis calculation that can achieve accuracy comparable to hourly simulation models RETScreen ® is an annual analysis calculation that can achieve accuracy comparable to hourly simulation models RETScreen ® can provide significant preliminary feasibility study cost savings RETScreen ® can provide significant preliminary feasibility study cost savings

17 © Minister of Natural Resources Canada 2001 – Questions? Ground-Source Heat Pumps Project Analysis Module RETScreen ® International Clean Energy Project Analysis Course For further information please visit the RETScreen Website at


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