1

Proposed Changes to the RTF’s Heat Pump Specifications

Impact on Estimated Deemed Savings and C&R Discount

Program Credits

2

PNW Climates Are Different Than That Used for ARI Ratings

• ARI performance ratings (SEER & HSPF) are based on climates that do not match the Northwest’s.– Heating Zone 1 climate is warmer than the rating

location – HSPF is higher than label– Heating Zones 2 & 3 climates are colder than the

rating location – HSPF is lower than label– All of the Cooling Zones in NW has lower humidity

than the rating location – SEER is lower than label

3

Climate Adjusted HSPF

104%105% 92% 91% 89%

0%

20%

40%

60%

80%

100%

Per

cent

of

AR

I R

atin

g

Portland Seattle Boise Spokane Missoula

4

Duct Leakage and Insulation Levels Have Interactive Affects on System Efficiency

• Duct leakage and conductive losses reduce heat pump capacity.

• Duct leakage and conductive losses increase “buffer space” temperatures.

• As a result, duct location, duct leakage and insulation levels must all be modeled to determine overall “duct system” efficiency.

5

Duct “System” Assumptions

• Four Duct Configurations– Crawlspace – Supply ducts 100% outside conditioned space– ½ Basement - Supply ducts 50% outside conditioned space– Full Basement - Supply ducts 100% inside conditioned space– Manufactured Home - Supply ducts 100% outside conditioned space

• Three Levels of Leakage– 10% - Base– 7.5% - RTF– 5% - PTCS

• Two Levels of Duct Insulation– R-4 – Base– R-11 (R-8 installed) – RTF & PTCS

6

Duct System Efficiency Adjusted HSPF – All Ducts Outside Conditioned Space

75%

80%

85%

90%

95%

100%

Portland Seattle Boise Spokane Missoula

Per

cent

of

AR

I R

atin

g

Crawlspace - Base Crawlspace - RTF Spec Crawlspace - PTCS Spec

7

Duct System Efficiency Adjusted HSPF – > 50% Ducts Outside Conditioned Space

75%

80%

85%

90%

95%

100%

Portland Seattle Boise Spokane Missoula

Per

cent

of

AR

I R

atin

g

1/2 Basement - Base 1/2 RTF Specment - RTF Spec 1/2 PTCS Specment - PTCS Spec

8

Duct System Efficiency Adjusted HSPF – Manufactured Home Supplies Outside Conditioned Space

75%

80%

85%

90%

95%

100%

Portland Seattle Boise Spokane Missoula

Per

cent

of

AR

I R

atin

g

Manufactured Homes - Base Manufactured Homes - RTF SpecManufactured Homes - PTCS Spec

9

Duct System Efficiency Adjusted HSPF – All Ducts Inside Conditioned Space

75%

80%

85%

90%

95%

100%

Portland Seattle Boise Spokane Missoula

Per

cent

of

AR

I R

atin

g

Full Basement - Base Full RTF Specment - RTF SpecFull PTCS Specment - PTCS Spec

10

Commissioning Heat Pumps – Adjustments for Improper Air Flow and Refrigerant Charge

• Field studies of heat pump and air conditioner installations reveal

– Over/Under Charging of Refrigerant

– Low air flow across evaporator coils

• RTF Specifications require:– Air flow verification using either flow plate or “temperature rise” &

“volt/amp” methods

– Refrigerant charge verification “according to manufacturer’s instructions”

• PTCS Specifications require:– Air flow verification using flow plate (TrueFlow)

– Refrigerant charge verification using SubCool/SuperHeat in AC mode.

11

Commissioning Adjusted HSPF

75%

80%

85%

90%

95%

100%

Per

cent

of

Rat

ed H

SPF

Portland Seattle Boise Spokane Missoula

12

Control Impact Assumptions

• Base Case Assumptions– Combination Timer Defrost (20%) & Demand Defrost (80%)

– Some (20%) of systems have w/low ambient temperature compressor “cutouts”

– Some (20%) systems have resistance backup tied to “first stage” of heat pump

• RTF Assumptions– Demand Defrost Only

– Some (20%) systems have outside thermostats which limit “backup” above 35F

– No resistance backup tied to “first stage” of heat pump

• PTCS Assumptions– Demand Defrost Only

– All systems have outside thermostats which limit “backup” above 35F

13

Control Adjusted HSPF

75%

80%

85%

90%

95%

100%

Per

cent

of

Rat

ed H

SPF

Portland Seattle Boise Spokane Missoula

14

Cumulative Adjusted HSPF – All Ducts Outside Conditioned Space

0%

20%

40%

60%

80%

100%

Per

cent

of

Rat

ed H

SPF

Portland Seattle Boise Spokane Missoula

Base RTF Spec PTCS Spec

15

Cumulative Adjusted HSPF – 50% Ducts Outside Conditioned Space

0%

20%

40%

60%

80%

100%

Per

cent

of

Rat

ed H

SPF

Portland Seattle Boise Spokane Missoula

Base RTF Spec PTCS Spec

16

Cumulative Adjusted HSPF – All Ducts Inside Conditioned Space

0%

20%

40%

60%

80%

100%

Per

cent

of

Rat

ed H

SPF

Portland Seattle Boise Spokane Missoula

Base RTF Spec PTCS Spec

17

Cumulative Adjusted HSPF – Manufactured Homes – All Supplies Outside Conditioned Space

0%

20%

40%

60%

80%

100%

Per

cent

of

Rat

ed H

SPF

Portland Seattle Boise Spokane Missoula

Base RTF Spec PTCS Spec

18

SEER Adjustment

• High performance air conditioning equipment is designed to “de-humidify” by recovering latent energy (heat of condensation)

• ARI Test Conditions assume inside temperature of 80F and outside temperature of 82F and relative humidity @100%, 90% and 80%

• Preliminary research appears to show that SEER ratings, when adjusted for the PNW “dry-summer” climate are about 65% of nameplate

19

Other Factors That Are Changing RTF’s Heat Pump Savings

• Revised estimates of “post-weatherization” space heating use– Reduced loads

• Revised estimate of air conditioning loads– New estimates based on hourly modeling of specific

prototypes

• Better calibration with metering studies for space heating and cooling

20

Pre1980 Construction “Post Weatherization” Forced Air Furnace Space Heating Use

0

5,000

10,000

15,000

20,000

25,000

Zone 1 Zone 2 Zone 3

Ann

ual U

se (

kWh)

Original Estimate Revised Estimate

21

Post79/Pre93 Construction Forced Air Furnace Space Heating Use

0

5,000

10,000

15,000

20,000

25,000

30,000

Zone 1 Zone 2 Zone 3

Ann

ual U

se (

kWh)

Original Estimate Revised Estimate

22

Post92 Construction Forced Air Furnace Space Heating Use

0

4,000

8,000

12,000

16,000

20,000

Zone 1 Zone 2 Zone 3

Ann

ual U

se (

kWh)

Original Estimate Revised Estimate

23

Revised Estimates of Air Conditioning Loads Are

Lower (e.g.,Pre1980 Construction)

0

500

1,000

1,500

2,000

2,500

3,000

3,500

Portland Seattle Boise Spokane Missoula

Original Space Cooling Load (kWh/yr) Revised Space Cooling Load (kWh/yr)

24

Revised Estimates of Air Conditioning Load Are

Lower (e.g., Post92 Construction)

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

Portland Seattle Boise Spokane Missoula

Original Space Cooling Load (kWh/yr) Revised Space Cooling Load (kWh/yr)

25

Some Revised Estimates of Air Conditioning Load Are Higher

and Lower (e.g.,Post79/Pre93 Construction)

0500

1,0001,5002,0002,5003,0003,5004,0004,500

Portland Seattle Boise Spokane Missoula

Original Space Cooling Load (kWh/yr) Revised Space Cooling Load (kWh/yr)

26

Overall Implications for C&R Discount Values

• Difference Between “PTCS” Heat Pump (or CAC) Installations & Non-“PTCS” Installations Increases

• Difference between Non-PTCS Heat Pump (or CAC) Installations and “Baseline” Installations Decreases

27

Air Source Heat Pump Savings for Pre1980 FAF w/o CAC with PTCS

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

Heating 1Cooling 1

Heating 1Cooling 2

Heating 1Cooling 3

Heating 2Cooling 1

Heating 2Cooling 2

Heating 2Cooling 3

Heating 3Cooling 1

Heating 3Cooling 2

Heating 3Cooling 3

Ann

ual S

avin

gs (

kWh)

Current with PTCS Revised with PTCS

28

Air Source Heat Pump Savings for Post79/Pre93 FAF w/o CAC with PTCS

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

Heating 1Cooling 1

Heating 1Cooling 2

Heating 1Cooling 3

Heating 2Cooling 1

Heating 2Cooling 2

Heating 2Cooling 3

Heating 3Cooling 1

Heating 3Cooling 2

Heating 3Cooling 3

Ann

ual S

avin

gs (

kWh)

Current with PTCS Revised with PTCS

29

Air Source Heat Pump Savings for Post1992 FAF w/o CAC with PTCS

0

2,000

4,000

6,000

8,000

10,000

12,000

Heating 1Cooling 1

Heating 1Cooling 2

Heating 1Cooling 3

Heating 2Cooling 1

Heating 2Cooling 2

Heating 2Cooling 3

Heating 3Cooling 1

Heating 3Cooling 2

Heating 3Cooling 3

Ann

ual S

avin

gs (

kWh)

Current with PTCS Revised with PTCS

30

Air Source Heat Pump Savings for Pre1980 FAF w/o CAC – with RTF Specification

0

2,000

4,000

6,000

8,000

10,000

12,000

Heating 1Cooling 1

Heating 1Cooling 2

Heating 1Cooling 3

Heating 2Cooling 1

Heating 2Cooling 2

Heating 2Cooling 3

Heating 3Cooling 1

Heating 3Cooling 2

Heating 3Cooling 3

Ann

ual S

avin

gs (

kWh)

Current without PTCS Revised without PTCS

31

Air Source Heat Pump Savings for Post79/Pre93 FAF w/o CAC – with RTF Specifications

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

Heating 1Cooling 1

Heating 1Cooling 2

Heating 1Cooling 3

Heating 2Cooling 1

Heating 2Cooling 2

Heating 2Cooling 3

Heating 3Cooling 1

Heating 3Cooling 2

Heating 3Cooling 3

Ann

ual S

avin

gs (

kWh)

Current without PTCS Revised without PTCS

32

Air Source Heat Pump Savings for Post1992 FAF w/o CAC – with RTF Specifications

01,0002,0003,0004,0005,0006,0007,0008,0009,000

10,000

Heating 1Cooling 1

Heating 1Cooling 2

Heating 1Cooling 3

Heating 2Cooling 1

Heating 2Cooling 2

Heating 2Cooling 3

Heating 3Cooling 1

Heating 3Cooling 2

Heating 3Cooling 3

Ann

ual S

avin

gs (

kWh)

Current without PTCS Revised without PTCS

33

Air Source Heat Pump Savings for Pre1980 FAF w/o CAC – with PTCS vs. RTF

Specifications

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

Heating 1Cooling 1

Heating 1Cooling 2

Heating 1Cooling 3

Heating 2Cooling 1

Heating 2Cooling 2

Heating 2Cooling 3

Heating 3Cooling 1

Heating 3Cooling 2

Heating 3Cooling 3

Ann

ual S

avin

gs (

kWh)

PTCS Specification RTF Specifications

34

Air Source Heat Pump Savings for Post79/Pre93 FAF w/o CAC – with PTCS vs. RTF Specifications

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

Heating 1Cooling 1

Heating 1Cooling 2

Heating 1Cooling 3

Heating 2Cooling 1

Heating 2Cooling 2

Heating 2Cooling 3

Heating 3Cooling 1

Heating 3Cooling 2

Heating 3Cooling 3

Ann

ual S

avin

gs (

kWh)

PTCS Specifications RTF Specifications

35

Air Source Heat Pump Savings for Post1992 FAF w/o CAC – with PTCS vs. RTF Specifications

01,0002,0003,0004,0005,0006,0007,0008,0009,000

Heating 1Cooling 1

Heating 1Cooling 2

Heating 1Cooling 3

Heating 2Cooling 1

Heating 2Cooling 2

Heating 2Cooling 3

Heating 3Cooling 1

Heating 3Cooling 2

Heating 3Cooling 3

Ann

ual S

avin

gs (

kWh)

PTCS Specifications RTF Specifications

36

City of Richland Savings Estimates

• Based on sub-metered data on 54 homes

• Average house size = 2071 sq.ft.

• Average savings = 5552 kWh/yr– (2.7 kWh/sq.ft./yr)

• Average HSPF = 8.24

• Un-reported Pre-conversion space conditioning use and CAC system

37

RTF Estimates Compared to City of Richland’s

Analysis – Heating Only Savings

   City of Richland

 Original w/PTCS

 Revised w/PTCS

Original w/o PTCS

Revised w/o PTCS

House Size

2,071 – 2,136

1,600 -2,200

1,600 -

2,200

1,600 -

2,200

1,600 -

2,200

Savings (kWh/yr) 5,552 –6,706

8,560 – 10,062

5,184 – 8,530

7,532 –8,899

4,537 – 7,467

Savings/Ton (kWh/yr)

1,828 - 2,154

2,853 – 2,875

1,728 – 2,437

2,511 – 2,543

1,512 – 2,143

Savings/sq.ft./ floor area

2.7 – 3.1

4.6 - 5.3

3.2 – 3.9

4.0 - 4.7

2.8 - 3.4

38

Recommendations

• Adopt revised deemed savings estimates for air source heat pump conversions (and heat pump and CAC efficiency upgrades)

• Consider using kWh/sq.ft./yr as “deemed unit” rather than kWh/yr/home

• Revise assumptions in Heat Pump HSPF and CAC SEER “Tradeoff Calculator” to match deemed savings analysis