Presentation on theme: "RTF: Deemed Measure Analysis: Ground Source Heat Pumps Final Summary and Recommendation April 5th, 2011."— Presentation transcript:
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 Recommendations
RTF GSHP Deemed Measure Study Objectives
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
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. 6 th, GSHP Measure Review and Research: Jan 25 th GSHP SEEM Integration and Costs : Feb. 23 rd, GSHP Draft Recommendations : Mar. 16 th, GSHP RTF Presentations : April 5 th, 2011
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.
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.
Assumptions and Base-case
Typical GSHP System
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)
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 F 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)
GSHP Energy Modeling Approach
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 )
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
GSHP Total Pipe Length Results (NC) Total foot of pipe in ground depth5' 8' HOUSEHZ1HZ2HZ Total Design Heat Load (Btu/hr) HZ1HZ2HZ ,350 24,559 28, ,562 31,881 37, ,506 28,555 32, ,292 48,275 55,778
GSHP Loop Size/Ton of House Load Foot of pipe per ton of house load, NOT equipment load depth5' 8' HOUSEHZ1HZ2HZ 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.
GSHP Installed Costs (inside only) Heat Pump Size All Inside Heat Pump, pumps, piping w/ no ducts Price Per Ton 2$6,633$3,316 3$7,319$2,440 4$8,576$2,144 5$9,556$1,911 6$10,100$1,683
GSHP Loop Costs $1300 per 600’ loop and trench, all pricing scaled from this.
Desuperheat $500 adder without preheat tank $1000 adder with preheat tank Range of DHW savings kwh (only runs when heat pump runs).
Missoula Study Calibration Source
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)
Calibration Results MT Study N= 19 SEEM Floor Area (ft^2) Heat Pump Size (tons) Equipment Heat Output (kWh) GSHP+Aux (kWh) Aux Heat (kWh) Space Heating Savings (kWh) Useable Desuperheat (kWh) 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.
Outline Specs GSHP AHRI Rating Point (COP-3.7 at 32F EWT, EER 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.
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 should be explored as future scope.