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RTF: Deemed Measure Analysis: Ground Source Heat Pumps Final Summary and Recommendation

RTF: Deemed Measure Analysis: Ground Source Heat Pumps Final Summary and Recommendation. April 5th, 2011. GSHP Deemed Measure Analysis . Project Objectives Assumptions and Basecase GSHP Energy Modeling Methodolgy GSHP Sizing GSHP Costs SEEM Runs and Calibration ProCost Runs and Analysis

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RTF: Deemed Measure Analysis: Ground Source Heat Pumps Final Summary and Recommendation

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  1. RTF: Deemed Measure Analysis:Ground Source Heat PumpsFinal Summary and Recommendation April 5th, 2011

  2. GSHP Deemed Measure Analysis • Project Objectives • Assumptions and Basecase • GSHP Energy Modeling Methodolgy • GSHP Sizing • GSHP Costs • SEEM Runs and Calibration • ProCost Runs and Analysis • Recommendations

  3. RTF GSHP Deemed Measure Study Objectives

  4. Subcommittee Members David Baylon, Shawn Oram, Ben Larson, Poppy Storm- Ecotope Tom Eckman – NW Council Gillian Charles - NW Council Adam Hadley – Hadley Energy Warren Cook - PECI Danielle Gidding – BPA Gary Grayson – Idaho Power Todd Greenwell - Idaho Power Jim Haberman - BPA David Hales – WSU Energy Office Mark Jerome – KAM Energy/Pacific Air Comfort Mark Johnson – BPA Bruce Manclark – Delta T David Maul - Maul Energy Advisors Jim Maunder - Ravalli Electric Andres Morrison – Ecos Consulting Guy Nelson - UGWG Nick O’Neil - Energy Trust Brady Peeks - NW Energy Works Dennis Rominger – PSE

  5. Summary of Activities Conference calls and Goto Meetings were setup with the Sub-Committee on the following dates. 1. GSHP Sub-Committee Kickoff Meeting: Jan. 6th, 2011 2. GSHP Measure Review and Research: Jan 25th 2011 3. GSHP SEEM Integration and Costs : Feb. 23rd, 2011 4. GSHP Draft Recommendations : Mar. 16th, 2011 5. GSHP RTF Presentations : April 5th, 2011

  6. Review of Scope: Update Ground Source Heat Pump (GSHP) measure definitions, energy savings, costs, cost-effectiveness, and status for GSHP measures for Single Family and Manufactured Homes.

  7. GSHP Deemed Savings Sub-Measures • GSHP upgrade from an ASHP • PTCS Duct Sealing • PTCS Cx, controls and sizing • De-superheat for DHW • Note: GSHP is last measure in. PTCS duct sealing, Cx, controls and sizing are already present in the ASHP base.

  8. Assumptions and Base-case

  9. Typical GSHP System

  10. Prototype Modeling • Four Prototype homes • Manufactured home 1568sf • Single Family 2200sf • Single Family w/Bsmt 2688sf • Large Single Family 5000sf (Non-Standard Prototype) • 3 Heating Zones, 3 Cooling Zones • Heating, Cooling, and DHW impacts • C/B Analysis (ProCost)

  11. Systems Assumption Basecase Systems • Airside Source Heat Pump (HSPF 8.5, SEER 14) • Electric DHW (0.90 EF) • Retrofit, Fully Weatherized • New Construction • PTCS Duct Sealing, Cx, Controls and Sizing Proposed Systems • Water-to-Air Heat Pump ((COP 3.7 32F EWT, 18.2 EER 77F EWT) w/ ECM Motor, CV, single stage compressor) • GSHP sized to meet load at 25 deg F OSA • Electric Resistance installed • w/ and w/o DHW Desuperheater buffer tank • Horizontal Closed Loop Focus (lowest cost loops)

  12. GSHP Energy Modeling Approach

  13. Outline of Modeling • Develop GSHP W:A Heat Pump into SEEM. • Develop annual ground loop curve into SEEM • Develop De-Superheater Savings into SEEM • Calibration with actual ground source heat pump energy monitoring study performed in1996 on mulitple sites in MT.(Missoula GSHP Study: co-op Maunder 1996 )

  14. Heat Pumps: Heating Capacity

  15. Heat Pumps: Heating Performance

  16. Ground Loop Curves Used

  17. GSHP Sizing & Costs

  18. System Sizing Assumptions • Base-Case: ASHP sized to meet load at 30 deg OSA temp. • Proposed: GSHP sized to meet load at 25 deg OSA and 30 degree EWT. • Ground Loop is sized using IGSHPA’s CLGS program. • Inputs: • 1. Full Load Hours: (Total BTU’s)/(Heat Pump Capacity) (Used SEEM for BTU’s) • 2. Desired Loop Design Temp = 30F EWT • 3. Ground Characteristics and Location • 4. Loop Type (Used 4 Pipe Trenches) • Outputs: • Total Loop Length Calculated

  19. GSHP Total Pipe Length Results (NC)

  20. GSHP Loop Size/Ton of House Load Example: 1568 house in HZ2 is 24,559 btu/hr peak load. Sizing selection is 2 ton of GSHP w/elec resistance and (4x) 600’ ground loops.

  21. GSHP Installed Costs (inside only)

  22. GSHP Loop Costs • $1300 per 600’ loop and trench, all pricing scaled from this.

  23. GSHP/ASHP System Costs (NC)

  24. GSHP Incremental Costs (NC)

  25. Desuperheat $500 adder without preheat tank $1000 adder with preheat tank Range of DHW savings 800-2200 kwh (only runs when heat pump runs).

  26. Calibration

  27. Missoula Study Calibration Source

  28. SEEM GSHP Module Calibration • Metered data on 19 houses with GSHPs: Missoula Electric Cooperative GSHP Demonstration Project, 1996 • Created SEEM runs based on reported insulation values & floor areas. • Two SEEM prototypes used (1344 over sealed crawl and 2688 basement) to match average floor area • Strategy: • Match reported equipment output to SEEM equipment output • No heat pumps involved in this step – it validates the inputs only • Use validated inputs with GSHP model • Matched GSHP design: 45F loop (vertical bores in aquifer) • Very little auxiliary heat reported so used 35F outside T lockout to limit aux heat use in simulations • Next step is to derate COP of SEEM GSHP to match those in 1996 study (3.72.5) • Final piece is determining useable desuperheat energy (simply used a multiplier to derate SEEM output to match metered data accounting for COP differences)

  29. Calibration Results • Match is good. • No tweaks to set point or internal gains were made. Duct sealing was reported so was used. No special infiltration measures used (0.35ACHn). • Weather file used was Missoula TMY3 but reported energy data was not weather normalized.  potential source of error. • But, graph in report shows mean daily temperature reported was slightly higher than a “normal” year. “Normal” not defined.

  30. SEEM Runs & Pro-Cost Runs

  31. Weatherized SEEM/ProCost Results

  32. New Construction SEEM/ProCost Results

  33. Outline Spec & Recommendations

  34. Outline Specs • GSHP AHRI Rating Point (COP-3.7 at 32F EWT, EER-18.2 at 77 deg F EWT) • Ducted Ground Source Heat Pumps shall be sized to meet load at 25 F OSA temp and assume 30 F incoming loop temps. • Ducted GSHP shall include resistance heat with lockout over 35 F OSA temps. • Ground Loops shall be designed for 30 deg entering water temps at peak using an IGSHPA recognized sizing program. • Loop pumps shall be sized no larger than 150 watts/nominal ton of heat pump. • Desuperheater require a preheat buffer tank with no heat installed in preheat tank.

  35. Recommendations • Revise all existing measures with results from this analysis. • Adopt Savings Numbers for GSHP • List GSHP as NON-cost-effective deemed measure. • Ground Source Heat Pumps are NOT cost effective over ASHP’s. • B/C ratios with an electric furnace as the basecase unlikely to change significantly • Increase savings • Increase incremental costs.

  36. Discussion & Decisions

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