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Heat Pump Research Project Sponsored by the Heat Pump Working Group June 7, 2005.

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Presentation on theme: "Heat Pump Research Project Sponsored by the Heat Pump Working Group June 7, 2005."— Presentation transcript:

1 Heat Pump Research Project Sponsored by the Heat Pump Working Group June 7, 2005

2 Project Goals 1.Assess energy use and savings from heat pumps installed under C&RD/ConAug and EWEB. 2.Assess base case installation practices. 3.Assess heat pump performance under laboratory conditions to identify optimal settings. 4.Assess the general approach of installers to control, sizing and performance issues, and of manufacturers to new technologies, etc.

3 Billing Results

4 EWEB Billing Analysis Results

5 C&RD / ConAug Billing Analysis Results Revised ResultsPrevious Results

6 Billing Analysis Results by System Type

7 Billing Analysis Results by Building Type C&RD MH Cases NAC Saved by System Type with 90% C.L., n= ,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 Heat Pump FAF w/CAC FAF w/oCAC Zonal All SysTypes All C&RD MF kWh/year C&RD SF Cases NAC Saved by System Type with 90% C.L., n= ,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 Heat Pump FAF w/CAC FAF w/oCAC Zonal All SysTypes All C&RD SF kWh/year

8 Billing Analysis Results by Vintage MH NAC Saved with 90% C.L. by Vintage Bin, n= ,000 2,000 3,000 4,000 5,000 6,000 7, All C&RD kWh/year Legend: 1 Pre – Post 94

9 Realization Rates by Program Year Base Prog Year AreanGross NAC kWh/yr Net NAC kWh/yr 90% CI Antici- pated kWh/yr RR Zone 15184,6984, ,28863% Zone 33183,7953, ,81554% All C&RD 8364,3544, ,10860%

10 Realization Rates for C&RD Calculator, Initial

11 Realization Rates, Revised

12 kWh Savings estimates

13 Laboratory Results

14 HSPF: Fixed Orifice & TXV

15 Summary of Lab Results Impacts of refrigerant charge minimal except at very reduced levels (70% of specification) Impacts of air flow also limited to cases with very low air handler flow (less than 300 CFM/ton). Low air flow appears to occur in about 25% of “base case” installation practice TXV improves overall performance but has minimal impacts on the effects of low charge and low air flow C d higher than modeling assumptions for fixed orifice, lower than assumption for TXV Defrost degradation factors largely stable at values near the modeled and manufacturer’s assumptions.

16 Field Data Summary

17 Field Study Overview 160 field sites in 4 regions (Central Oregon, Kitsap Peninsula, Clark Co., Yakima/Walla Walla) started September 2004 “Base case” sites, chosen at random to represent non- PTCS installations –Combine field findings with billing data to recalibrate performance assumptions used in RTF calculations On-site review consists of two visits –Duct/house review (complete) –Heat pump review by service tech. (110 sites now in, additional 15 sites expected)

18 Site Selection Sites selected via random telephone dial to have air- source heat pump and be within appropriate utility territory Sites might have basements/interior ducts Clark County chosen vs. Portland because of paucity of HPs in PDX Pacific Power svc territory –Clark actually has HP inspection program so non-typical vs other areas

19 Key Audit Outputs (house/duct) House heat loss rate (UA) –Integral part of modeling house performance vs bills –Includes infiltration component (blower door test) System airflow (CFM) –System capacity & efficiency Duct system insulation and leakage –System operating pressures also measured Duct leakage fraction (%) –Effect on overall delivery efficiency/energy use Homeowner interaction with system (via survey)

20 Key Audit Outputs (heat pump review) HP control strategy –Indoor thermostat type, setting and staging –Outdoor thermostat presence, setting and operation –Compressor low ambient cut out Refrigerant charge level

21 Building Characteristics – Heat Loss Rate

22 Blower Door Results –Median ACH 50 is 7.6 for 149 clean cases; mean is 8.3 –This converts to median ACH nat of 0.38 –Highest ACH –Lowest ACH

23 Blower Door Results by Vintage Bin

24 Duct Leakage Fraction (all sites)

25 Duct Leakage by Vintage Bin Supply SideReturn Side

26 Supply vs. Return Leakage

27 System Fan Flow Median flow is 340 CFM/ton (n=126) Lower quartile is <=292 CFM/ton ECM cases (n=21*), median flow is 338 CFM/ton *final # will be larger

28 Airflow Distribution

29 System airflow by size of outdoor unit Tons

30 Refrigerant Charge Evaluation Review predominantly done in swing seasons –Heating season evaluation combined tech’s review of operating pressures and sensible split in context of ambient temp., system airflow, coil match About 1/3 of systems evaluated in cooling only mode or in addition to heating mode –Superheat/subcooling evaluation

31 Charge Results 60% of cases evaluated as having correct charge 28% of cases evaluated as being overcharged 10% of cases evaluated as being undercharged –2 had serious leaks (no refrigerant)

32 Refrigerant Charge Digest Over/undercharge amounts likely under-reported vs weigh-in approach However, cases of severe undercharge were very limited ½ of overcharged cases had an accumulator 2/3 of remaining overcharged cases were units with Trane compressors or scroll compressors

33 Heat Pump Efficiency HSPF by RegionHSPF by Equipment Size

34 HVAC Usage (from median low bill analysis of 124 bills) Heating - Annual kWhCooling - Annual kWh

35 Normalized Heating Load by Vintage and Region Heating - Annual kWh/sfTotal Usage - Annual kWh/sf

36 Normalized Heating Usage RegionNo Wood WoodTotal Bend Clark Kitsap Yakima Total Impact of wood – Annual kWh/sfPercentage of Sample Using Wood

37 Modeled Duct Efficiency (efficiency of 1 is perfect ducts) By RegionBy Vintage

38 Duct Insulation Supply vs. Return UAR-Value of Supply Ducts

39 TXV Summary (Outdoor Unit)

40 TXV Summary (Indoor Unit)

41 Thermostat/Homeowner Interaction ~80% of systems have programmable stats… ~1/3 of occupants say they understand their thermostat and/or like how it keeps their house comfortable ~1/3 say they tolerate their thermostat (but wish they understood it better) ~1/3 have thrown up their hands and use the HOLD feature

42 Controls: Indoor Thermostat 78% programmable Median heating setpoint: 70  F Median setback: 65  F 55% of systems with setback > 5  F –Estimated 75% of programmable stats have adaptive recovery

43 Controls: Outdoor Thermostat About 35% of sites visited had an operating ODT (75% of Clark sites have ODT) Average setting 40° F About 2/3 of sites without ODTs had the extra wires needed to install one without fishing new wire Only 15% of systems had elements on in Stage 1 heating –Median on-time 5 minutes

44 Market Actor Interviews

45 HVAC Installer Interviews (detailed results) 32 shops throughout region in urban, suburban, rural areas (29 full interviews) Shops range from 2 trucks to 30, median of 6 Median 50% new construction Participants install all major (and some secondary) brands of equipment Almost all participants report use of non-intuitive heat pump and duct sizing tools (Manual J, Manual D, etc.) Wide range of experience with utility, state, national incentive/marketing campaigns and installation procedures

46 Technician Certification

47 Installer System Sizing Criteria

48 Characteristics of Efficient Line

49 Installation Characteristics - TXVs

50 Availability/cost of Outdoor Unit TXV

51 Acceptance of TXV Technology

52 Outdoor Thermostat/Low Ambient Cutout All “often” cases in TriCities/Yakima All “seldom” cases as above or Mid-Columbia

53 Installation Characteristics – Aux Heat Percentage of Respondents Never Often Seldom Element wired in first stage heating? Out of 7 cases answering “seldom” or “often”, 5 In Zone 2 (E Wash or Boise )

54 Installer Target System Airflow

55 R410a

56 PTCS

57 Familiarity With Third Party Charge Checking

58 Acceptance of Third Party Mechanisms

59 Energy Star

60 Penetration of Incentives & Tax Credits

61 Marketing Impacts

62 Challenges in Explaining Tax Credits/Incentives to Customers

63 Client Priorities

64 Comments on Thermostats

65 Perceived Trends


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