Residential Heat Pump Water HeatersUES Measure Update Proposal

Regional Technical ForumNovember 18, 2014

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Presentation Outline

• Measure Overview and Context• Summary of Provisional Measure and Research• Subcommittee Summary• Measure Savings, Cost, Life, TRC B/C• Proposed Decision

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Measure OverviewMeasure Developers Ecotope, NEEA, BPA

Contract Analyst Review Yes (Christian Douglass, Adam Hadley)

Technical Subcommittee Review Yes

Research & Evaluation Subcommittee Review

Not yet

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Context

• 55% of 4 million households in PNW have electric water heaters (2011 RBSA SF Survey)

• 2.7 people in a house use 3,380 kWh/yr on site (2014 RBSA Metering Study)

• 3.38 MWh/yr x 2.2 million households / 8760 hrs/yr = 850 aMW of site electricity

• HPWHs have roughly an annual COP of 2• Site electric savings potential = 425 aMW

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Provisional Measure Summary• Approved as Provisional UES on October 4, 2011 (Tier 2

ducted approved February 14, 2012)• The measures cross the entire PNW and are not separated by

climate zone

Annual Energy Saving (kWh/yr) Tier 1 Tier 2

HPWH Location Space Heat TypeSmall Tank

Large Tank Any Size

Unheated Buffer Location Any Heat Type 887 1,817 1,794 Interior Location Gas Heated 1,547 2,169 1,724 Interior Location Zonal Electric Heated 648 957 952 Interior Location Electric Furnace Heated 556 833 837 Interior Location Heat Pump Heated 1,189 1,686 1,243

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Research Plan (October 4, 2011)

7 Regional HPWH Research• Field Studies

1. “NEEA Heat Pump Water heater Field Study Report.” Fluid Market Strategies, for NEEA. October 22, 2013.2. “Heat Pump Water Heater Model Validation Study” DRAFT REPORT. Ecotope, for NEEA. July 28, 2014.

• Lab Coefficient of Performance (COP) Tests1. Larson, B. and M. Logsdon. “Laboratory Assessment of Sanden GES-15QTA Heat Pump Water Heater.” Ecotope

for NEEA. Nov 6, 2013.2. Larson, B., and Logsdon, M. February 2012. Laboratory Assessment of AO Smith Voltex Hybrid Heat Pump Water

Heater. Prepared for the Northwest Energy Efficiency Alliance. Retrieved from: https://conduitnw.org/_layouts/Conduit/FileHandler.ashx?RID=888

3. Larson, B., and Logsdon, M. February 22, 2012. Laboratory Assessment of AirGenerate ATI66 Hybrid Heat Pump Water Heater. Prepared for the Northwest Energy Efficiency Alliance. Retrieved from: https://conduitnw.org/_layouts/Conduit/FileHandler.ashx?RID=887

4. Larson, B., and Logsdon, M. September 2012. Laboratory Assessment of General Electric GeoSpring Hybrid Heat Pump Water Heater. Prepared for the Northwest Energy Efficiency Alliance. Retrieved from: https://conduitnw.org/_layouts/Conduit/FileHandler.ashx?RID=1183

5. Larson, B. March 2013. Laboratory Assessment of AirGenerate ATI80 Hybrid Heat Pump Water Heater. Prepared for the Northwest Energy Efficiency Alliance. Retrieved from: https://conduitnw.org/_layouts/Conduit/FileHandler.ashx?RID=1522

6. Larson, B. June 2013. Laboratory Assessment of Rheem HB50RH Heat Pump Water Heater. Prepared for the Northwest Energy Efficiency Alliance. Retrieved from: https://conduitnw.org/_layouts/Conduit/FileHandler.ashx?RID=1646

7. Larson, B., and Logsdon, M. August 2014. Laboratory Assessment of AO Smith SHPT-50 Heat Pump Water Heater. Retrieved from: https://conduitnw.org/Pages/File.aspx?RID=2179

• Space Heat Interaction Studies1. Widder SH, JM Petersen, GB Parker, and MC Baechler. July 2014. Impact of Ducting on Heat Pump Water Heater

Space Conditioning Energy Use and Comfort. PNNL-23526, Pacific Northwest National Laboratory, Richland, WA.

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RTF Research Plan & Outcomes• http://rtf.nwcouncil.org/meetings/2012/02/HPWH_Ducted_Interior_Instal

lations_Provisional_Proposal_021412_v5.pptx

Study Area Research Outcome Status

Hot Water Consumption

100+ Households successfully metered. Draw profiles created for 1, 2, 3, 4, & 5+ occupancy households

In-field COP • 100+ Households successfully metered.

• Inlet & outlet water temperature. • Ambient air temperature. • Water heater energy use.

Space Conditioning Interaction (non-ducted and exhaust ducted units)

Indeterminate

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Summary of Research Outcomes, By Parameter

Parameter Existing ProposedTank Setpoint ~122.5°F 128°F

Inlet Water Temperature

Assumed constant ~50°F Varies throughout the year and based on water source

Hot Water Consumption

45 gal/day with no draw schedule

40 gal/day average. Independent draw schedules for 1, 2, 3, 4, & 5+ person households

Ambient Space Temperatures

Estimates with “loosely” calibrated simulations

Calculated based on model fits to observed data

Heating System Interaction

100% 65% (subcommittee judgment)

HPWH Efficiencies Based on lab tests Based on lab Tests and calibrated to field data

Model Calibration Uncalibrated Calibrated

Subcommittee Summary: Dates & Attendees

October 21, 2014 (2 hours)

Link to PresentationLink to Meeting Notes

Attendees:• Jennifer Anziano• Christian Douglass• Ben Larson• Robert Weber• Aaron Winer• David Thompson• Josh Rushton• Andie Baker• Rick Knori• Brad Acker

November 6, 2014 (1.5+ hours)

Link to PresentationLink to Meeting Notes

Attendees:• Jennifer Anziano• Christian Douglass• Ben Larson• Robert Webber• Aaron Winer• David Thompson• Josh Rushton• Andie Baker• Mark Johnson• Dave Kresta• Sarah Widder• Kevin Price• Jeff Harris• Kevin Watier• Adam Hadley

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Subcommittee Summary: Consensus on Specifics

• Model calibration (10/21)– The HPWH model developed within SEEM is sufficiently calibrated for

the purposes of estimating a UES.• How to treat the impending federal water heater standard

(10/21)– Assume the federal standard goes into effect now (instead of April

2015). The staff resources to develop multiple measure sets is not worth the effort and could be cumbersome for programs.

• Whether to have an "any size" tank measure or separate small/large tank measures (10/21)– An "any size" measure based on the weighting of small and large

tanks in the region is appropriate. A relatively short sunset date (~1 year) should be used to monitor market shifts in average tank size.

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Subcommittee Summary: Consensus on Specifics (continued)

• Valuing self-install labor at zero cost (10/21)– Defer this discussion to the broader RTF, since it relates to the Guidelines

and many measures in addition to HPWH.• HVAC interaction for interior installations (11/6)

– Provisionally assume a heating interaction factor of HCf = 65% for exhaust ducted and non-ducted.

– Pursue a dual research plan using a.) the PNNL lab homes and b.) a “paper study” which looks at the correlation between temperature depression and HCf.

• Baseline for large tanks impacted by federal standard (11/11 - 11/14 over email)– Collecting data on existing tank size is appropriate– An additional or supplemental survey may be used to elicit baseline

information• Where to include houses with DHPs (11/11 - 11/14 over email)

– Bundle DHPs with Heat Pumps in the measure identifier

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HVAC Interaction Factor Research Options Considered

• Option 1: Additional study using PNNL lab homes (~$100k)– Will help provide a better understanding of the range of interaction factors by

testing four more HPWH locations throughout the lab home

• Option 2: “Paper study” (~$10k)– Low cost option using existing data and models to help bound interaction factor

• Option 3: Large scale, “flip-flop” field research study (~$1M)– The most comprehensive study, it would provide a direct output of the factor of

interest– Is such an expensive study worth it?

• Yes, because HPWH is a huge resource (~400 aMW) and our current uncertainty causes savings to vary by +/- 20%?

• Subcommittee recommends developing a research plan combining Options 1 and 2– Why? Options 1 and 2 are relatively low cost, yet they may bound the factor to

an acceptable level– If this turns out not to be the case, Option 3 is still on the table

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Proposed Measure Summary• 57 measure applications• Measures identified by tank location, HVAC type, efficiency, and exhaust

ducting (yes/no) (note: tank size not a proposed identifier at this time)

HZ1Location / HVAC Type Tier 1 Tier 2 Tier 2 Ducted

Interior Gas 1,231 1,309 1,218 Interior EFAF 892 911 798 Interior HP 1,089 1,134 1,047

Interior Zonal 930 956 786 Garage 1,016 1,220 N/A

Basement 1,116 1,223 N/A

HZ2Location / HVAC Type Tier 1 Tier 2 Tier 2 Ducted

Interior Gas 1,297 1,376 1,281 Interior EFAF 982 1,006 842 Interior HP 1,114 1,156 1,045

Interior Zonal 1,018 1,049 806 Garage 847 1,252 N/A

Basement 1,155 1,267 N/A

HZ3Location / HVAC Type Tier 1 Tier 2 Tier 2 Ducted

Interior Gas 1,328 1,436 1,337 Interior EFAF 1,040 1,096 900 Interior HP 1,143 1,208 1,059 Interior Zonal 1,074 1,136 849 Garage 708 1,287 N/A Basement 1,161 1,314 N/A

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Measure SavingsHeating Zone 1

Gar. = Garage, Base. = Basement

Gas EFAF HP Zonal Any Any Gas EFAF HP Zonal Any Any Gas EFAF HP Zonal Any AnyInterior Gar. Base. Interior Gar. Base. Interior Gar. Base.

Tier 1 Tier 2 w/ Exhaust Ducting Tier 2 NO Ducting

0

500

1,000

1,500

2,000

2,500

Existing, Large Tank Existing, Small Tank Proposed, Any Size Tank

Tota

l Sav

ings

(kW

h)

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Measure Savings (continued)Heating Zone 2

Gar. = Garage, Base. = Basement

Gas EFAF HP Zonal Any Any Gas EFAF HP Zonal Any Any Gas EFAF HP Zonal Any AnyInterior Gar. Base. Interior Gar. Base. Interior Gar. Base.

Tier 1 Tier 2 w/ Exhaust Ducting Tier 2 NO Ducting

0

500

1,000

1,500

2,000

2,500

Existing, Large Tank Existing, Small Tank Proposed, Any Size Tank

Tota

l Sav

ings

(kW

h)

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Measure Savings (continued)Heating Zone 3

Gar. = Garage, Base. = Basement

Gas EFAF HP Zonal Any Any Gas EFAF HP Zonal Any Any Gas EFAF HP Zonal Any AnyInterior Gar. Base. Interior Gar. Base. Interior Gar. Base.

Tier 1 Tier 2 w/ Exhaust Ducting Tier 2 NO Ducting

0

500

1,000

1,500

2,000

2,500

Existing, Large Tank Existing, Small Tank Proposed, Any Size Tank

Tota

l Sav

ings

(kW

h)

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Cost & Life• Measure life

– Existing: 15 yrs (Source: ??)– Proposed: 13 yrs (2009 DOE TSD)

• Incremental Cost

Tier 1 Tier 2 w/ Exhaust Ducting

Tier 2 NO Ducting $-

$200 $400 $600 $800

$1,000 $1,200 $1,400 $1,600 $1,800 $2,000

Existing, Large Tank

Existing, Small Tank

Proposed, Any Size Tank

2006

$

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TRC B/C Ratios

Heating System Location Tier Climate ZoneHZ1 HZ2 HZ3

AnyGarage Tier1 1.6 1.3 1.1

Tier2 0.7 0.8 0.8

Basement Tier1 1.8 1.8 1.8Tier2 0.7 0.8 0.8

Zonal Electric Resistance

Interior Tier1 1.3 1.4 1.5Tier2 0.5 0.6 0.6

Ducted Tier2 0.4 0.4 0.4

Electric Furnace Interior Tier1 1.2 1.4 1.4Tier2 0.5 0.6 0.6

Ducted Tier2 0.4 0.4 0.4

Heat Pump Interior Tier1 1.6 1.6 1.6Tier2 0.7 0.7 0.7

Ducted Tier2 0.5 0.5 0.5

Gas Furnace Interior Tier1 1.4 1.6 1.6Tier2 0.7 0.7 0.8

Ducted Tier2 0.6 0.6 0.6

Proposed Decision

“I ______ move the RTF:• Update the savings, cost, and life for the HPWH UES

measures as proposed and set the measure to Provisional category and Under Review status

• Direct staff to develop research plan focused on:1. HVAC interaction factor, using a combination of a PNNL lab homes

study and a paper study, as proposed; and2. Determining baseline for large tanks (>55 gal), using data on existing

tank size and possibly survey data.

• Set the sunset date to 4/2015, at which time the RTF will review the proposed research plan, and if approved, set the measure to Active status.”

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Backup Slides

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Heating System Interaction• Applies only to interior ducted or non-ducted installations (i.e. garage and

unconditioned basement installs are excluded from this discussion)• Heat pump water heaters extract heat from the space where they are

installed. Some of that heat energy is replaced by the heating system.• We have observed that not every unit of energy removed from the air by

the HPWH is replaced by the heating system

Electric Storage Tank Water HeatersLocation Overall nBasement 29% 240Main House 44% 361Garage 19% 155Crawl 4% 31Other 3% 27

Is the WH Space Location Conditioned?Location No YesBasement 16% 84%Main House 5% 95%Garage 92% 8%Crawl 86% 14%Other 75% 25%Overall 30% 70%

Source: RBSA

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• HVAC System Interaction = m*cp*ΔT + QUA

• Typical air Δ T at 68F entering air: ~15F

Warm House Air

Cool HPWH Exhaust Air

Tank Heat Losses

Conditioned Space Installation Heat Flows

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• HVAC System Interaction = m*cp*ΔT + QUA

• Δ T now depends on outside air T• m now depends on added infiltration load

Warm House Air

Cool HPWH Exhaust Air

Tank Heat Losses

Ducted to Outside, Conditioned Space Heat Flows

Added Infiltration Load

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Available Studies

• Field study of HPWH interaction factors was inconclusive• What we know from PNNL Lab Homes Study1

– Interaction factor for interior HPWH installations ≈ 49%– Interaction factor for ducted HPWH installations ≈ 44%– Study looked at one installation of a HPWH in a closet next to an

exterior wall

1 PNNL. Impact of Ducting on Heat Pump Water Heater Space Conditioning Energy Use and Comfort. July 2014.

26 PNNL Study – Water Heater Location

PNNL. Impact of Ducting on Heat Pump Water Heater Space Conditioning Energy Use and Comfort. July 2014.

27 Logic Behind 65% Heating Interaction Assumption

• Subcommittee agreed that HVAC factor would differ for heated basements versus more central, “main house” locations

• Assume HVAC factor of 50% for heated basements, 75% for main house

• Weight these by RBSA saturation for electric tank locations (basement - 36.8%, main house – 63.2%)

• Weighted average ≈ 65%