Heat Pump Water Heaters

Heat Pump Water Heaters

Provisional UES Proposal Regional Technical Forum

October 4th, 2011

UES Analysis by: B. LarsonRTF Staff Review by: A. HadleyPresentation by: B. Larson, A. Hadley, K. Bedney, J. Harris

2

Introduction• More time for discussion today than at the last meeting• Decision today?

– We’ll see how it goes.• What changed from last meeting

– 45 gal/day• (was 40 gal/day for small tank and 60 gal/day for large tank)

– Aggregated many measures (from 108 to 15 measures)– Tank size definitions

• Small: 50 to 75 gallons – (was 55 gal or less)

• Large: more than 75 gallons– (was greater than 55 gal)

– Other more minor changes (we’ll point them out)

3

Measure Summary• Measure name: Heat Pump Water Heater• Measure description

– Installation of a heat pump water heater instead of a standard electric tank water heater in single family site built homes.

• Measure type: UES• Today’s Request: Discussion, Review, (Decision???)• Change in measure status: Proposed Provisional• Change in measure savings: n/a• Change in measure cost effectiveness: n/a• Other or follow-on work for RTF: Tier 2 interior

4

UES Analysis Summary

5

Measure Classification and PropertiesMarket Sector ResidentialMarket Segment Water HeatingMeasure Category Heat Pump Water HeaterMeasure Description Installation of a Northern Climate-compliant heat

pump water heater instead of a standard electric tank water heater in single family site built residences.

Sunset Criteria not established

Primary Workbook Res_HPWH_v0_8.xlsmLinked Workbooks PNWClimateZones_6thPlan.xls, Copy of

PNWResSectorSupplyCurveUnits_6th_Fnl.xls, ResDHWFY10v2_1.xls, OccupantsperHomebDwellingType.xlsx

Number of Measures, and UES Components

15 measures with 3 UES components each. - 3 Efficiency Levels/Tank Size- 5 Installation Locations

6

Measure IdentifiersIdentifierEfficiency Level/Tank Size

HPWH Installation Location

Possible Values Further Explanation and SourcesTier 1 Small Tank; Tier 1 Large Tank;

Tier 2 (any tank size)

Tier levels defined by NEEA Northern Climate HPWH specification.

Tier 2 interior must have exhaust duct connected.

Small Tank: 50 to 75 gallonsLarge Tank: Greater than 75 gallons

Unheated Buffer Location; Interior (gas heat; hp; eFAF; or zonal electric)

Unheated Buffer Location is defined as a space which:a) is adjacent to the thermal boundary of the house, and b) has no positive heat supply under thermostatic control.

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ParameterAmbient Temperature Inside Conditioned SpaceWater Heater Temperature Rise

Baseline Water Heater Heat Loss Rate

People Per Single Family House

Hot Water Consumption

Constant Parameters

68 deg F

45 gal/day

72.5 °F Outlet water temperature of 122 °F to 127 °F based on measurements from Quaid, Maureen, Rick Kunk le and Brian Lagerberg, 1991. RCDP 2 Appliance Analysis, Washington State Energy Office, August 1991

Inlet Water Temperature of 52 °F based on average of outdoor temperatures + 2 °F based on Roos, Carolyn and David Baylon, 1993. Non-Space Heating Electrical Consumption in Manufactured Homes RCDP Cycle II. Ecotope Inc. May 1993.

2.47

Small Tank: 1.83 Btu/F/hrLarge Tank: 2.89 Btu/F/hr

Small Tank: EF 0.921; Large Tank: EF 0.888.(Source: ResDHWFY10v2_1.xls. Weighted average EF of tanks on the

market.)

Possible Values Further Explanation and Sources

Source: "Non-Space Heating Electrical Consumption in Manufactured Homes RCDP Cycle II" study gave an equation for DHW energy use as a function of people in the household (1169 kWh/person + 624 kWh). That equation matches closely both the MH and SF RCDP 2 results. Using that equation for 2.47 people per household results in 45 gallons per day per house (assuming 72.5 delta T).

Other Studies:a.) Analysis of 10 field studies in the US showed an average and median daily hot water use of 58.7 and 50.6 gallons per day, respecitvely. "...daily hot water use is highly variable both among residences and within the same residence." Lutz, J.D., et.al. "Hot Water Draw Patterns in Single-Family Houses: Findings from Field Studies. LBNL. May 2011.b.) Ductless Heat Pump project (preliminary data) showed general agreement with the RCDP but also shows a potential, slight downward trend in energy use per occupant ~80kWh/yr.c.) EPRI/BPA field sites showed 67 gpd (n=3) for the 80 gallon AO Smith unit and 46 gpd (n=21) for the 50 gallon GE unit.

US Census Bureau's American Housing Survey (n=17,232 homes in ID, WA, OR, & MT)

[Note: EPRI study had 2.825 people per house, n=40]

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ParameterBaseline Water Heater COP versus Ambient Temperature

HPWH COP versus Ambient Temperature

Basement Annual Temperature Profile

For each tank size, calculated based on baseline water heater heat loss rate, hot water consumption, and a 75 degree water heater temperature rise at each

ambient temperature bin.

see graph on 'Presentation' tab

see graph on 'Presentation' tab Basement annual temperature profile developed using SEEM simulation model.

see graph on 'Presentation' tab Tier 1 - Small Tanks: For ambient temperatures above 50 deg, linear regression of COP versus ambient temperature generated using average daily data from the EPRI/BPA field study for the 21 GE sites (up to 4 months of data per site - Jan 2011 through April 2011). For ambient temperatures below 50 degrees, field data for the GE units are used directly.

Tier 1 - Large Tanks: For ambient temperatures below 60 degrees, EPRI/BPA field study data for the 3 AO Smith sites are used directly. Since there were no field data above 60 degrees ambient temperature, lab test results of compressor COP and tank heat loss (Larson, Ben. "Interim Report and Preliminary Assessment of AO Smith Voltex PHPT-80 Hybrid Heat Pump Water Heater." Prepared for BPA. 7/12/2011. ) are used in conjunction with field COP and daily water use data at lower ambient temperatures to determine resistance element runtimes. Calculated resistance element runtime at 57 deg F (0.17 hrs/day) is assumed along with lab reported COP to determine average COP.

Tier 2 - Small Tanks: The intermediate efficiency outputs of the Northern Climate Energy Factor calculation (COP's for each temperature bin derived from a line drawn through EF67 and EF50) for the ATI 66 model are used. There are no field data available for small Tier 2 units, so this was used as a proxy because performance is expected to be the same for each size category in Tier 2 due to the limitation put on operation of resistance heat.

Tier 2 - Large Tanks: The intermediate efficiency outputs of the Northern Climate Energy Factor calculation (COP's for each temperature bin derived from a line drawn through EF67 and EF50) for the ATI 66 model are used.


9

ParameterGarage Annual Temperature Profile

Heating/Cooling System Efficiencies

Heating Zone Weightings

Unheated Buffer Location Weightings

Heating System Weightings

Tier 2 Tank Size Weightings

Small Tank: 75%Large Tank: 25%

Estimated. Small tank expected to make up majority.

see graph on 'Presentation' tab Basement annual temperature profile developed using SUNCODE hourly simulation model.


Gas FAF: AFUE 0.90Heat Pump: HSPF 8.5Central AC: SEER 13.0

Duct System Efficiency: 90%

Estimated.

Heating Zone 1: 80%Heating Zone 2: 15%Heating Zone 3: 5%

Source: PNWClimateZones_6thPlan.xls

Garage: 50%Unheated Basement: 50%

Estimated.

Gas FAF: 64%Heat Pump: 13%

Zonal Electric: 11%Electric FAF: 12%

PNWResSectorSupplyCurveUnits_6th_Fnl.xls

10

0.700

0.800

0.900

1.000

27 32 37 42 47 52 57 62 67 72 77 82

COP

Ambient Temperature (deg F)

Baseline Water Heater COP versus Ambient Temperature

Small Tank - EF 0.921 at 45 gal/day Large Tank - EF 0.888 at 45 gal/day

11

0.00

0.50

1.00

1.50

2.00

2.50

3.00

27 32 37 42 47 52 57 62 67 72 77 82

COP

Ambient Temperature (deg F)

HPWH COP versus Ambient TemperatureTier 1, <= 75 gal Tier 1 > 75 gal Tier 2 (both sizes)

12

0.00

0.05

0.10

0.15

0.20

0.25

0.30

77726762575247423732

Frac

tion

of D

ays i

n Bi

n

Temperature Bin (deg F)

Unheated Basement Annual Temperature Profile

Heating Zone 1Heating Zone 2

Heating Zone 3

13

0.00

0.05

0.10

0.15

0.20

0.25

0.30

77726762575247423732

Frac

tion

of D

ays i

n Bi

n

Temperature Bin (deg F)

Garage Annual Temperature Profile

Heating Zone 1

Heating Zone 2

Heating Zone 3

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Unit Energy Savings (UES) Estimation Method, Parameters and Sources

Measure Type

UES Component Analysis approach

Primary Parameter / Adjustment Factor

Baseline Description Efficient Case Description Baseline

Source Efficient Case Source

DHW Savings

Energy consumption for baseline and efficient case determined by applying the water heater annual COP to the daily hot water consumption and water heater temperature rise.

For Tier 2, results are aggregated using Tier 2 Tank Size Weightings.

Water Heater Annual COP

Small Tank: 0.9

Large Tank: 0.89

Tier 1: small: 1.69; large: 2.29 Tier 2: 2.19

Baseline Water Heater COP at 67 degrees Ambient Temperature

HPWH COP at 67 degrees Ambient Temperature

Space Heating Savings

Space Cooling Savings

Tier 1:<= 55 gal: 535 Btu/hr

> 55 gal: 718 Btu/hr

Tier 2:TBD

(will be calculated using SEEM)

Not a HPWH, so no heat extracted.

Compressor daily runtime determined for 67 deg ambient temperature using compressor COP from lab data (Larson studies), system COP from field data (EPRI/BPA), and hot water consumption assumption of 49 gal/day. HPWH heat extracted calcuated as sum of heat pump heat extracted (based on compressor COP and power from lab data and runtime) and standby losses heat extracted (a negative value).

HPWH - Inside

Conditioned Space

SEEM runs of a well insulated 2200 ft2 prototype for each of the three heating system types with (efficient case) and without (baseline) HPWH heat extracted from inside of the house. (Uses the standard SEEM internal gains input.)

Results are aggregated using Heating System Weightings, Heating Zone Weightings, and, for Tier 2, Tier 2 Tank Size Weightings.

HPWH Heat Extracted

0

15

Measure Type

UES Component Analysis approach

Primary Parameter / Adjustment Factor

Baseline Description Efficient Case Description Baseline Source Efficient Case Source

DHW Savings

Energy consumption for baseline and efficient case determined by applying the water heater annual COP to the daily hot water consumption and water heater temperature rise.

Water Heater Annual COP

BasementSmall Tank: HZ1: 0.88 HZ2: 0.88 HZ3: 0.87Large Tank: HZ1: 0.87 HZ2: 0.87 HZ3: 0.87

GarageSmall Tank: HZ1: 0.88 HZ2: 0.88 HZ3: 0.87 Large Tank: HZ1: 0.87 HZ2: 0.87 HZ3: 0.86

BasementTier 1: HZ1: small: 1.36; large: 2.02 HZ2: small: 1.26; large: 1.87 HZ3: small: 1.17; large: 1.72 Tier 2: HZ1: 2.05; HZ2: 2.02; HZ3: 1.99

GarageTier 1: HZ1: small: 1.32; large: 1.93 HZ2: small: 1.26; large: 1.81 HZ3: small: 1.08; large: 1.44Tier 2: HZ1: 2.04; HZ2: 2.01; HZ3: 1.64

Baseline Water Heater COP versus Ambient Temperature applied to the Basement and Garage Annual Temperature Profiles.

HPWH COP versus Ambient Temperature applied to the Basement and Garage Annual Temperature Profiles.

Space Heating Savings

Space Cooling Savings

1st & 4th Quarters (winter): 210 Btu/hr2nd Quarter (spring): 380 Btu/hr3rd Quarter (summer): 540 Btu/hr

Not a HPWH, so no heat extracted.

Using average field measured system COP's for AO Smith (> 55 gal) and GE (<= 55 gal) models from EPRI/BPA data, determine compressor daily runtime using average compressor COP's from lab data (Larson studies) and hot water consumption assumption of 49 gal/day. HPWH heat extracted calcuated as sum of heat pump heat extracted (based on compressor COP and power from lab data and runtime) and standby losses heat extracted (a negative value). Winter applies to 47 degree ambient, spring to 57, and summer to 67.

HPWH - Unheated

Buffer Location

Basement: SEEM runs of a well insulated 2200 ft2 prototype for each of the three heating system types with (efficient case) and without (baseline) HPWH heat extracted from the basement. (Uses a custom-modified version of SEEM.) The basement slab and walls are uninsulated. The basement ceiling is insulated.

Garage: House space heating and cooling energy requirements estimated using SUNCODE hourly simulations of the 2200 ft2 prototype with minimal insulation in the wall and ceiling connecting the house and garage. Heating system efficiencies applied to model outputs to determine space heating and cooling energy use.

Results are aggregated using Heating Zone Weightings, Unheated Buffer Location Weightings, and, for Tier 2, Tier 2 Tank Size Weightings.

Water Heater Heat Extracted

from Unheated Buffered Location

0

16

Measure CostSize Category Case Model

Equipment Purchase

Price (2011$'s)GE 50 gal $1,000 at sears.com 75% to GE / 25% to AO SmithAO Smith 60 gal $1,653 at lowes.com Whirlpool Model #:HPE2K60HD045V

Baseline 50 gal EF 0.921 417$ ResDHWFY10v2_2.xls 2008 Summit Blue Cost StudyTier 1 AO Smith 80 gal 2,024$ $2024 at lowes.com HPE2K80HD045V

Baseline 75 gal EF 0.888 542$ ResDHWFY10v2_2.xls 2008 Summit Blue Cost StudyAir Generate 50 gal Air Generate $1,699 MSRP for ATI 50Air Generate 66 gal Air Generate $1,999 MSRP for ATI 6650 gal EF 0.92175 gal EF 0.888

Large

Source & Notes

SmallTier 1 1,163$

2008 Summit Blue Cost StudyResDHWFY10v2_2.xlsBaseline

Tier 2Any

448$

1,849$

Item Cost (2011 $'s) Source NotesInc. Install (Small) 113$ Inc. Install (Large) 125$ Louvered Door Adder 51$ Source: DOE TSD. Applies to interior Tier 1 applications only.Exhaust Venting Adder 275$ Source: DOE TSD. Applies to interior Tier 2 applications only.Annual O&M 29$ Clean Filter:1/4hr @$25/hr once/yr + Ref.Service: DOE TSD pg.8-B-4

Other Costs

DOE TSD (incr. labor + condensate + drain pan incr. cost)

17

Measure Life

• 15 years– Same as standard RTF water heater measures.– Northern Climate Specification warranty

requirements:• Tier 1: 6 years (Energy Star)• Tier 2: 10 years

18

Intermediate Values &

Measure Aggregation Methodology

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WeightingsHeating Zone 1 80%Heating Zone 2 15%Heating Zone 3 5%

Garage 50%Unheated Basement 50%

Gas FAF 64%Heat Pump 13%Zonal Electric 11%Electric FAF 12%

Small Tank 75%Large Tank 25%

Tier 2 Tank Size Weightings (Estimated)

Heating System Weightings (6th Plan)

Heating Zone Weightings (6th Plan)

Unheated Buffer Location Weightings (Estimated)

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HPWH Location Size HZ1 HZ2 HZ375 gallons or lessgreater than 75 gallons75 gallons or less 3233 3243 3255greater than 75 gallons 3415 3432 345275 gallons or less 3236 3244 3290greater than 75 gallons 3420 3434 3510

Unheated Basement

Garage

Baseline Energy Use (kWh/yr)

Heated Basement or Inside

31863339

21

Note: These values do not take into account space heat interaction.

HZ1 HZ2 HZ3 HZ1 HZ2 HZ375 gallons or lessgreater than 75 gallons75 gallons or less 860 692 519 1809 1794 1777greater than 75 gallons 1850 1660 1517 2003 1997 199075 gallons or less 1052 958 612 1824 1808 1529greater than 75 gallons 1924 1841 1504 2009 1998 1749

Garage

14792081


Unheated Basement

Tier 1 Tier 2DHW Energy Savings (kWh/yr)

HPWH Location Size

18702023

HZ1 HZ2 HZ3 HZ1 HZ2 HZ375 gallon or less -914 -936 -998 -1205 -1229 -1312

greater than 75 gallon -1234 -1260 -1344 -1205 -1229 -1312Unheated Basement any -187 -202 -227 -187 -202 -227

Garage any -194 -187 -213 -194 -187 -21375 gallon or less -360 -439 -551 -474 -460 -606





greater than 75 gallon -32 -32 -35 -31 -32 -34Unheated Basement any in therms in therms in therms in therms in therms in therms

Garage any in therms in therms in therms in therms in therms in therms

75 gallon or less -38 -39 -42 -50 -51 -55greater than 75 gallon -51 -52 -57 -50 -51 -55

Unheated Basement any -6 -6 -7 -6 -6 -7Garage any -8 -7 -9 -8 -7 -9

Space Heating Savings (kWh/yr)Tier 2Tier 1

Htg System HPWH Location Size

Heat Pump

Gas

Heated Basement or InsideZonal

Electric



Gas(furnace fan)


Space Heating Savings (therms/yr)

Eletric FAF


Tier 1 Tier 275 gallon or less 91 118

greater than 75 gallon 121 118Unheated Basement any 36 36

Garage any 10 10

Space Cooling Savings (kWh/yr)PNW

ModelHPWH LocationClg System

13 SEER


22

• Annual Savings (kWh/yr)

One Unheated

Buffer Space, Small Tank, Tier 1

Measure

One Unheated

Buffer Space, Large Tank, Tier 1

Measure

One Unheated

Buffer Space Tier 2

Measure

Eight Interior Tier 1 Measures

Four Interior Tier 2

Measures

HZ1 HZ2 HZ3 HZ1 HZ2 HZ375 gallons or less Heated Basement or Inside 656 634 573 783 758 676greater than 75 gallons Heated Basement or Inside 967 942 857 937 912 83075 gallons or less Unheated Basement 709 525 328 1657 1628 1586greater than 75 gallons Unheated Basement 1698 1493 1326 1851 1831 179975 gallons or less Garage 868 781 409 1641 1631 1327greater than 75 gallons Garage 1741 1664 1301 1825 1821 1546




Tier 1 Tier 2

Tier 1 Tier 2

Tier 1 Tier 2

Tier 1 Tier 2

Zonal Electric Heated Home

Heat Pump Heated Home

Gas Heated Home

Electric Furnace Heated Home

23

• B/C Ratio’sHZ1 HZ2 HZ3 HZ1 HZ2 HZ3

75 gallons or less Heated Basement or Inside 0.8 0.8 0.7 0.5 0.5 0.5greater than 75 gallons Heated Basement or Inside 0.7 0.7 0.6 0.7 0.6 0.675 gallons or less Unheated Basement 0.9 0.7 0.4 1.4 1.3 1.3greater than 75 gallons Unheated Basement 1.3 1.2 1.0 1.5 1.5 1.575 gallons or less Garage 1.1 1.0 0.5 1.4 1.3 1.1greater than 75 gallons Garage 1.4 1.3 1.0 1.5 1.5 1.3

HZ1 HZ2 HZ3 HZ1 HZ2 HZ375 gallons or less Heated Basement or Inside 1.5 1.4 1.2 1.1 1.1 1.0greater than 75 gallons Heated Basement or Inside 1.3 1.2 1.1 1.2 1.2 1.175 gallons or less Unheated Basement 1.0 0.8 0.6 1.4 1.4 1.4greater than 75 gallons Unheated Basement 1.4 1.2 1.1 1.6 1.6 1.675 gallons or less Garage 1.3 1.1 0.7 1.4 1.4 1.2greater than 75 gallons Garage 1.4 1.4 1.1 1.6 1.6 1.4



Zonal Electric Heated Home

Heat Pump Heated Home

Gas Heated Home

Tier 1 Tier 2Electric Furnace Heated Home

Tier 1 Tier 2

Tier 2Tier 1

Tier 1 Tier 2

24

Results

25

Tier 1 Tier 1 Tier 2HPWH Location Space Heat Type Small TankLarge Tank Any SizeUnheated Buffer Location Any Heat Type 881 1,811 1,913 Interior Location Gas Heated Home 1,547 2,169 TBDInterior Location Zonal Electric Heated Home 648 957 TBDInterior Location Electric Furnace Heated Home 556 833 TBDInterior Location Heat Pump Heated Home 1,189 1,686 TBD

Tier 1 Tier 1 Tier 2HPWH Location Space Heat Type Small TankLarge Tank Any SizeUnheated Buffer Location Any Heat Type (4) (4) (4) Interior Location Gas Heated Home (38) (52) TBD

Tier 1 Tier 1 Tier 2HPWH Location Space Heat Type Small TankLarge Tank Any SizeUnheated Buffer Location Any Heat Type 1.1 1.4 1.6 Interior Location Gas Heated Home 1.6 1.4 TBDInterior Location Zonal Electric Heated Home 0.8 0.7 TBDInterior Location Electric Furnace Heated Home 0.7 0.6 TBDInterior Location Heat Pump Heated Home 1.5 1.3 TBD

Tier 1 Tier 1 Tier 2HPWH Location Space Heat Type Small TankLarge Tank Any SizeUnheated Buffer Location Any Heat Type 859$ 1,608$ 1,516$ Interior Location Gas Heated Home 910$ 1,659$ 1,792$ Interior Location Zonal Electric Heated Home 910$ 1,659$ 1,792$ Interior Location Electric Furnace Heated Home 910$ 1,659$ 1,792$ Interior Location Heat Pump Heated Home 910$ 1,659$ 1,792$

Annual Energy Saving (kWh/yr)

TRC B/C Ratio's

Annual Energy Saving (therms/yr)

Capital Cost (2011$'s)

26

Plans for Additional UES’s

• Tier 2, Interior, with required Exhaust Duct– Plan to model within revised version of SEEM

• New SEEM model (available this month) will perform a more detailed hourly simulation of whole house infiltration

– This will include the ability to input exhaust fan schedules.

27

Study Design From the Guidelines, for provisional UES status: “A study design has been developed that is likely to result in data on efficient-case energy consumption that will support RTF approval for active UES values.”

28

Study Design• Goal: Collect data useful in determining the next iteration of provisional UES

for heat pump water heater measures.– Intentionally straying from Guidelines’ purpose of provisional data collection due to:

• measure’s potential importance to the Region• expected evolution of HPWH technology over the next few years

• Three primary data collection areas– Hot Water Consumption– Space Conditioning Interaction (model inputs)– In-field COP

• Study Dates– Site/Participant recruitment

• Program participants through 3/31/2013• Overlap of site selection across data collection areas expected

– Study data collection period: 6/1/2013 – 5/31/2014• Installation of monitoring equipment would occur well before 6/1/2013

– Provisional UES Sunset Date: 12/31/2014

29

Study Area: Hot Water Consumption

• Data Collected– Monthly hot water consumption (gallons)

• Sample– 200 sites

• Random/representative sample of program participants

30

Study Area: Space Heat Interaction

• Data Collected– Unheated Buffer Space-to-House UA– Unheated Buffer Space estimate of internal gains

(equipment audit)• Sample

– 50 sites

31

Study Area: In-Field COP• Data Collected

– Hot water consumption (gallons)– Unheated Buffer Space-to-House UA– Unheated Buffer Space estimate of internal gains (equipment audit)– HPWH energy consumption

• Compressor and Fan• Electric resistance

– ΔT of water delivered– Ambient temperature– For tier 2 (assumes constant speed fan):

• Two-time measurement of – airflow – incoming air temperature

• Sample– 75 sites

• Site selections weighted by program occurrence of HPWH model, installation location, and heating zone.

32

Guideline Response Notes

1. Introduction and PurposeSponsor(s) BPASavings Estimation Method

Unit Energy Savings XPriority High High regional savings potential. High regional interest.

2. Measure SpecificationMeasure Identifiers Yes

Savings Baseline Yes

Implementation Standards Yes

Product Standards Yes Northern Climate specifications will be finalized in September 2011.

3. Unit Energy SavingsProvisionalSufficient data collection ?

UES adopted ?

Sunset criteria Yes 12/31/2014

Type of Estimation Procedure Yes Calibrated Engineering

Input Parameters Yes

Model Calibration ? DHW energy use known from field data, but space interaction not.

UES Components Yes DHW savings, space heat savings, space cool savings

Interactions between Measures Yes

Heating/Cooling Interactions Yes

Reliable Baseline Data ? Is 45 gpd reliable?

Reliable Efficient-case Data No Need larger sample size & more variation. Space interaction estimated.

Model Calibration - Baseline ?

Model Calibration - Efficient-Case No 2.5 people per household?

Sound Analyses Used ? Many assumptions used regarding space heat interaction.

3.2.3 Standard for Reliability Did RTF determine savings were reliable? ?

Summary Sheet Completed? YesMeasure Classification and Properties YesMeasure Identifiers YesConstant Parameters YesEstimation Method, Parameters and Sources Yes

Costs estimated YesMeasure Effective Useful Life (years) YesProCost analysis complete Yes

3.4 Documentation

Standard

Checklist: Guidelines for the Development and Maintenance of RTF-Approved Measure Savings Estimates

3.2 Required Quality of Savings

Estimate

3.1 UES Estimation Procedure

33

Discussion

34

Open Issues (1)• Baseline Energy Use Reliability

– RCDP cycle 2 data too old? (from early 1990’s)– Is the 2.5 people/house assumption reliable?– Applying 45 gpd to both tank sizes

• Will it “reliably” represent the future program participants?

35

Open Issues (2)

• Study Design– Adequate Study Areas?– Sample sizes?

• Need input/statistics applied• Operating modes – will study design capture the

“average” operating mode?– Length of study– Need a Control Group?

36

Open Issues (3)• Analysis Approach

– Gallons Per Day versus Household Size• Current proposal does not distinguish between household

size.– Gallons Per Day versus ODT

• Current proposal assumes the same volume of water every day of the year.

• RCDP (kWh/month) and EPRI (gal/month) data show significant variation by month; DOE TSD shows significant variation by season.

• Study Design allows future analysis to vary gal/day by outdoor temperature.

– Space Heat Interaction

37

Open Issues (4)

• Sunset Date– 12/31/2014

• Expected timing for study results and analysis completion

– Also• New/revised equipment expected• New Federal Standard effective April 16, 2015

• Measure Life

38

IF there were to be a motion today, it MIGHT look something like this:

“I _________ move that the RTF approve the UES for Heat Pump Water Heaters under provisional status with a sunset date of December 31st, 2014.”

(Tier 2 interior location heat pump water heaters will be pursued/added at a later date.)

Documents

Heat Pump Water Heaters