1 Performance of Heat Pumps in the Pacific Northwest Larry Palmiter Erin Kruse Ecotope, Inc. Presentation for RTF Meeting Portland, OR November 4, 2003

2 Overview of Presentation RTF Calculations and Basic Results Heat Pump Basics HSPF and SEER Heat Pump Sizing Duct Efficiency Model Details of Bin Model Calculations

3 Outline of Calculations Load simulation using Sunday Model Uses building UA, setpoints, window area and orientation, internal gains, and weather data Accounts for thermal storage, setpoints, solar and internal gains No ducts Produces annual space heat kWh Calibrate Ecotope Bin Model Select gains level in bin model to match annual space heat for same UA and weather site

4 Outline of Calculations (cont) Develop scaling and sizing criteria Develop scaling laws for heat pump capacity, CFM and input power Develop criteria for sizing heat pump for each prototype and climate Use calibrated bin model Estimate heat pump and electric furnace performance for selected combinations of duct parameters for each prototype and climate zone Use results to create simple RTF estimation method

5 RTF Estimation for Annual kWh Heat kWh = Heating load / (M*HSPF) M = DM*OM*CM*(7.2+EF*(HSPF-7.2)) Cool kWh = Cooling Load / (N*SEER) N = DM*CM*(10+EF*(SEER-10)) where (Note: values differ for HSPF and SEER) DM = duct efficiency multiplier OM = control option multiplier (not used for SEER) CM = climate multiplier EF = enhancement factor Separate DM for each of many cases

6 House 4 UA 377RTF Multipliers CONTROL OPTIONS (OM) PORSEABOISPKMIS 5KW Strip Heat with Compressor KW Strip Heat below 30°F Compressor off below 30°F CLIMATE (CM) PORSEABOISPKMIS HSPF Climate Multiplier SEER Climate Multiplier ENHANCEMENT (EF) PORSEABOISPKMIS HSPF Enhancement Factor SEER Enhancement Factor RTF Multipliers (No Ducts)

7 Heat Pump Basics In heating mode Capacity goes down with lower outdoor temp. Power input goes down with lower outdoor temp. COP goes down with lower outdoor temp. In cooling mode Capacity goes down with higher outdoor temp. Power input goes up with higher outdoor temp. COP goes down with higher outdoor temp. Note all capacity, power input and COP values include effects of fan heat

8 Heat Pump Basics (cont) Overall performance depends on –Efficiency of equipment –Climate –Size of heat pump relative to load (inc. ducts) –Duct Losses –Two-stage thermostat behavior

9 From ASHRAE 2000 Systems and Equipment Handbook

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11 HSPF 9.0 SEER 14.5 HSPF 7.2 SEER 10 Heat Pump COP vs Temp.

12 Bin Hours for NW Climates

13 HP Factors Not Present in RTF Several factors affecting energy use are not (yet) included in the RTF results –Two-stage thermostats may result in auxiliary strip heat use when setback is used –Crankcase heater energy: about 65 W when compressor not running –Use of auxiliary strip heat during defrost: could be estimated from known defrost time –Altitude effects

14 New Advanced Heat Pumps There are two promising new approaches to improved cold climate performance –Cold Climate Heat Pump HSPF = 9.6 SEER = 16 in Zone 5 Capacity = 4 tons at 0 F, no strip heat above 0 F –Reverse Cycle Chiller Concept Large heat pump with water storage tank No strip heat above 0 F

15 HSPF and SEER Based on Standard published in 1979 HSPF –Size minimum design load to capacity at 47 F –Bin method for six climates and several loads –Warning: label is only for Zone 4, min. load SEER –Based on wet coil tests at 82 F outdoor temp. –Includes Part Load Factor at 50% duty

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18 1½ Ton 2½ Ton 3 Ton 3½ Ton 4 Ton 5 Ton 2 Ton Zone 4 Zone 5 Slope = 480 UA/ton = 160 ARI Method of Sizing Load for 3 Ton Heat Pump Slope = 600 UA/ton = 200 Slope = UA / Duct Eff.

19 TestCoilIndoor TemperatureOutdoor Temperature SEER Dry Bulb °FWet Bulb °FDry Bulb °FWet Bulb °F A- Steady State Wet B- Steady State Wet C- Steady State Dry80< D- Cycling 6 min on, 24 off Dry80< HSPF High Temp- Steady State Dry Low Temp- Steady State Dry Frost Accumulation Dry Cycling 6 min on, 24 off Dry Laboratory Tests Used to Calculate HSPF & SEER

20 Zone Design Temperature Calculated HSPF, YKC Calculated HSPF, YSA 1 37°F °F °F °F °F °F Carrier 38YKC, nominal HSPF 7.2, nominal SEER 10.0, CFM 1250, Cd 0.14 Carrier 38YSA, nominal HSPF 9.0, nominal SEER 14.5, CFM 1050, Cd 0.06 HSPF Calculations for 6 Zones

21 DOE/ARI Calculation of Heating Season Performance Factor (HSPF) Calculations use the equations in ARI Standard 210/240 (2003) Appendix C5.2 (formerly Appendix A) Programmed by Larry Palmiter, Ecotope Inc, September 2003 Defrost values at 35 F for capacity and input were estimated from values at 47 and 17 F using the formula in C page 19 Coefficient of Degradation at part load was estimated from cooling mode EER(82) and the SEER equations in C5.1.1 and assumed the same for heating. All heat flow values are in Btuh. Balance point of house is 65 F. SYS is overall system efficiency including part load factor and backup heat. Heat Pump Model: YKC036 Capacity(47): Input(47): COP(47): 3.08 Capacity(35): Input(35): COP(35): 2.54 Capacity(17): Input(17): 9625 COP(17): 2.22 Coefficient of Degradation:.14

22 ZONE Heating Outdoor Design Temperature (F) Minimum Design Heat Requirement (Btuh) Minimum UA (Btuh/F) Standard Minimum Heat Requirement (Btuh) Standard Minimum UA (Btuh/F) Tout Binfr Qload Capacity Auxiliary Input PLF COP SYS HSPF = 9.04 Rated Zone 4 HSPF = 7.20 Sum of Bin Fractions = 1

23 ZONE Heating Outdoor Design Temperature (F) Minimum Design Heat Requirement (Btuh) Minimum UA (Btuh/F) Standard Minimum Heat Requirement (Btuh) Standard Minimum UA (Btuh/F) Tout Binfr Qload Capacity Auxiliary Input PLF COP SYS HSPF = 8.75 Rated Zone 4 HSPF = 7.20 Sum of Bin Fractions = 1

24 ZONE Heating Outdoor Design Temperature (F) Minimum Design Heat Requirement (Btuh) Minimum UA (Btuh/F) Standard Minimum Heat Requirement (Btuh) Standard Minimum UA (Btuh/F) Tout Binfr Qload Capacity Auxiliary Input PLF COP SYS HSPF = 8.34 Rated Zone 4 HSPF = 7.20 Sum of Bin Fractions = 1

25 ZONE Heating Outdoor Design Temperature (F) Minimum Design Heat Requirement (Btuh) Minimum UA (Btuh/F) Standard Minimum Heat Requirement (Btuh) Standard Minimum UA (Btuh/F) Tout Binfr Qload Capacity Auxiliary Input PLF COP SYS HSPF = 7.66 Rated Zone 4 HSPF = 7.20 Sum of Bin Fractions = 1

26 ZONE Heating Outdoor Design Temperature (F) Minimum Design Heat Requirement (Btuh) Minimum UA (Btuh/F) Standard Minimum Heat Requirement (Btuh) Standard Minimum UA (Btuh/F) Tout Binfr Qload Capacity Auxiliary Input PLF COP SYS HSPF = 6.67 Rated Zone 4 HSPF = 7.20 Sum of Bin Fractions = 1

27 ZONE Heating Outdoor Design Temperature (F) Minimum Design Heat Requirement (Btuh) Minimum UA (Btuh/F) Standard Minimum Heat Requirement (Btuh) Standard Minimum UA (Btuh/F) Tout Binfr Qload Capacity Auxiliary Input PLF COP SYS HSPF = 8.85 Rated Zone 4 HSPF = 7.20 Sum of Bin Fractions =.999

28 Duct Efficiency Model A modified and expanded version of the model used in ASHRAE Standard 152 The model includes the following effects Conduction loss on supply and return side Air leakage on supply and return side Effect of unbalanced leakage on house infiltration Thermal regain of duct losses from buffer zones Capacity of equipment and mass flow rate of air Arrangement of ducts in buffer zones

29 BSR/ASHRAE Standard 152P This standard will be submitted to the American National Standards Institute Board of Standards Review (BSR) for approval. ASHRAE ® STANDARD PROPOSED AMERICAN NATIONAL STANDARD Method of Test for Determining the Design and Seasonal Efficiencies of Residential Thermal Distribution Systems THIRD PUBLIC REVIEW June 2001 ©2001 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. This draft has been recommended by the project committee and approved by a subcommittee of the Standards Committee for public review. Instructions and a form for commenting are provided with this draft. The changes proposed in this draft are subject to modification before final review and approval by ASHRAE. Although reproduction of drafts during the public review period is encour­aged to promote additional comment, permission must be obtained to reproduce all or any part of this document from the ASHRAE Manager of Standards, 1791 Tullie Circle, NE, Atlanta, GA Phone: , Ext Fax: The form for commenting and instructions may be obtained in electronic form from ASHRAE's Internet Home Page, Printed copies of a public review draft may be purchased from ASHRAE Customer Service, 1791 Tullie Circle, NE, Atlanta, GA E- mail: Fax: Telephone: (worldwide), or toll free (for orders in U.S. and Canada). AMERICAN SOCIETY OF HEATING, REFRIGERATING AND AIR-CONDITIONING ENGINEERS, INC Tullie Circle, NE · Atlanta GA

30 T room = T rr

31 Delivery Efficiency Both the model developed by Palmiter and Francisco (1997) (with the modifications found in Francisco and Palmiter 1999) and the one in Standard 152 use the same equation for the delivery efficiency under heating conditions, which is (1) whereη = delivery efficiency α s = leakage efficiency for supply ducts α r = leakage efficiency for return ducts β s = conduction efficiency for supply β r = conduction efficiency for return  t s = temperature difference between indoors and the ambient for the supply  t r = temperature difference between indoors and the ambient for the return  t e = temperature rise across heat exchanger Leakage efficiency can be defined as the fraction of the air handler flow that is delivered to the conditioned space by the ducts. From standard heat exchanger theory, the conduction efficiency can be expressed as, x = s (for supply) or x = r (for return)(2) whereA = surface area of ducts m e = mass flow of air through air handler fan at operating conditions C p = specific heat of air R = duct unit thermal resistance

32 Supply Duct Surface Area in Unconditioned Space and R-value (n=39) Variable MeanMin10%25%50%75%90%Max Supply Duct Area (ft 2 ) Pct. of Floor Area Supply R-value Duct Leakage Under Normal Operating Pressures as Percent of Air Handler Flow (n=48) Variable MeanMin10%25%50%75%90%Max Supply Nulling Supply Benchmark Supply Delta-Q Return Nulling Return Benchmark Return Delta-Q Recent Field Measurements of Duct Properties in Puget Sound Area Homes Source: Field Evaluation Of Improved Methods For Measuring The Air Leakage Of Duct Systems Under Normal Operating Conditions In 51 Homes. Published by Ecotope, October 2003

33 Heat Pump Sizing for RTF The overall performance of a heat pump in heating mode is strongly affected by the capacity relative to the building load In Pacific Northwest climates the cooling load is small relative to heating and predominantly sensible (dry coil) The next two slides show the sizing results for the RTF study

34 City / Design Temp Size (tons) UA / Ton Heating Duct Eff. Cooling Duct Eff. HSPF Multiplier SEER Multiplier Heating Sys. Eff. Cooling Sys. Eff. Heating kWH Cooling kWH Balance Point (F) POR 22 °F SEA 23 °F BOI 2 °F SPO 1 °F MIS -9 °F City / Design Temp Size (tons) UA / Ton Heating Duct Eff. Cooling Duct Eff. HSPF Multiplier SEER Multiplier Heating Sys. Eff. Cooling Sys. Eff. Heating kWH Cooling kWH Balance Point (F) POR 22 °F SEA 23 °F BOI 2 °F SPO 1 °F MIS -9 °F Typical Ducts: 10% leakage, R-4 nominal (R-3 act.) on both supply and return Good Ducts: 5% leakage, R-11 nom (R-8.25 act.) on both supply and return Heat Pump Sizing Results Carrier 38YKC, nominal HSPF 7.2, nominal SEER 10.0, CFM 1250, Cd 0.14 Ecotope Inc, September 28,2003 House 4, 1350 Sq. ft., UA 377

SEA SPO MIS POR BOI Slope = UA / Duct Eff. 1½ Ton 2½ Ton 3 Ton 3½ Ton 4 Ton 5 Ton 2 Ton

36 Detailed Bin Model Results The bin model has two modes of operation –In the first mode it automatically generates thousands of runs for analysis –In the second mode it generates detailed output tables and graphs for a particular run specification The following sets of slides show detailed results for Portland and Missoula for the typical ducts case.

37 PORTLAND: Typical Ducts YKC 2.13 Tons Ho = Hg = He = Ko = Kg = Ke = Jo = Jg = Buffer Zones = 2 As =.900 Ar =.900 Bs =.8808 Br =.9726 CFMe = 888 Theat = 65 Tcool = 75 Qgains = 3808 Tbalheat = Tbalcool = Tlow = -35 Tcomf = -35 Furn =.00 Kwadd=.00 To Hours DDbal Cap InKw COP Qbase Qdis Fon PLF Dte Qneed Qhp Qaux DuctEff SysEff Summary Toavg DDbal KWHbase KWHneed KWHhp KWHaux KWHtot DuctEff SysEff Savings relative to Cooling Electric Furnace Heating kWh Total %

38 Portland

39 Portland

40 Portland

41 Portland

42 MISSOULA: Typical Ducts YKC 4.06 Tons Ho = Hg = He = Ko = Kg = Ke = Jo = Jg = 9.98 Buffer Zones = 2 As =.900 Ar =.900 Bs =.9356 Br =.9855 CFMe = 1692 Theat = 65 Tcool = 75 Qgains = 4895 Tbalheat = Tbalcool = Tlow = -35 Tcomf = -35 Furn =.00 Kwadd=.00 To Hours DDbal Cap InKw COP Qbase Qdis Fon PLF Dte Qneed Qhp Qaux DuctEff SysEff Summary Toavg DDbal KWHbase KWHneed KWHhp KWHaux KWHtot DuctEff SysEff Savings relative to Cooling Electric Furnace Heating kWh Total %

43 Missoula

44 Missoula

45 Missoula

46 Missoula