1 air source heat pumps potential changes in the rtf’s specifications & savings estimates and...

1

Air Source Heat Pumps

Potential Changes in the RTF’s Specifications & Savings Estimates and Their Impact on C&R Discount

Program Credits

2

Why “Things” Are Changing – New Energy Star Specifications

• Energy Star labeled air source heat pumps established new performance criteria effective October 1, 2002– Split System Minimums

• SEER – 13.0

• HSPF - 8.0

• EER – 11.0

– Package System Minimums• SEER – 12.0

• HSPF – 7.6

• EER – 10.5

3

Why “Things” Are Changing – PNW Climates Are Different

• 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

4

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

5

Why Things Are Changing – Control Practices Reduce Performance

• Set-Back Thermostats (with or without “ramp up” features) often result in use of electric resistance heat

• Timed-defrost controls (particularly in Heating Zones 2 & 3) operate even when relative humidity is too low to produce icing

• Compressor “cut-out” temperatures are set too high, so compressor doesn’t operate even when it has a COP above 1.0.

6

Control Adjusted HSPF

94%97%

68% 65%62%

0%

20%

40%

60%

80%

100%

Per

cent

of

AR

I R

atin

g


7

Why Things Are Changing - Failure to Properly Commission Heat Pumps

• Field studies of heat pump and air conditioner installations reveal– Over/Under Charging of Refrigerant– Low air flow across evaporator coils

8

Commissioning Adjusted HSPF

94% 94%82% 82% 79%

0%

20%

40%

60%

80%

100%

Per

cent

of

Rat

ed H

SPF


9

Cumulative Adjusted HSPF

85% 88%

60% 59% 56%

0%

20%

40%

60%

80%

100%

Per

cent

of

Rat

ed H

SPF


10

SEER Doesn’t Match Label Either

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

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

– Nominal 10 SEER => Real 6.5 SEERNominal 10 SEER => Real 6.5 SEER

11

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

12

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

13

Post79/Pre93 Construction Forced Air Furnace Space Heating Use

0

5,000

10,000

15,000

20,000

25,000

30,000


Ann

ual U

se (

kWh)


14

Post92 Construction Forced Air Furnace Space Heating Use

0

5000

10000

15000

20000

25000


Ann

ual U

se (

kWh)


15

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


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

16

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



17

However, 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



18

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

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Air Source Heat Savings Adjustments for Pre1980 FAF w/o CAC – “Worst Case”

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

20

Air Source Heat Savings Adjustments for Post79/Pre93 FAF w/o CAC – “Worst Case”

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)


21

Air Source Heat Savings Adjustments for Post1992 FAF w/o CAC – “Worst Case”

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)


22

Air Source Heat Savings Adjustments for Pre1980 FAF w/o CAC – “Worst Case”

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

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Air Source Heat Savings Adjustments for Post79/Pre93 FAF w/o CAC – “Worst Case”

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)


24

Air Source Heat Savings Adjustments for Post1992 FAF w/o CAC – “Worst Case”

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)


Example 1 – Pre80 Single Family w/Furnace in Heating & Cooling Zone 1

Case Annual Savings (kWh)

C&R Discount Credit ($)

Current w/o PTCS 6,839 $ 2,241

Current w/PTCS 8,055 $ 2,661

Proposed w/o PTCS 4,298 $ 1,407

Proposed w/PTCS 6,484 $ 2,155

Example 2 – Post79/Pre93 Single Family w/Furnace in Heating Zone 1 & Cooling Zone 2







Example 3 – Post92 Single Family w/Zonal Heat & No CAC in Heating Zone 1 & Cooling Zone 3



Current w/o PTCS 2,944 $ 744


Proposed w/o PTCS 631 $ (136)

Proposed w/PTCS 2,906 $ 699

Example 4 – Pre80 Single Family w/Furnace & w/o CAC in Heating & Cooling Zone 2







29

RTF Estimates Compared to City of Richland’s Analysis

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

1,600

1,600

1,600

Savings (kWh/yr) 5,552 –6,706

8,560

6,444

7,532

4,495

Savings/Ton (kWh/yr)

1,828 - 2,154

2,853

2,148

2,511

1,498

Savings/sq.ft./ floor area

2.7 – 3.1

5.3

4.0

4.7

2.8

30

RTF Estimates Compared to City of Richland’s Analysis

City of Richland

Original w/PTCS

Revised w/PTCS

Original w/o PTCS

Revised w/o PTCS

CAC Use - (1,020) (1,254) (1,226) (1,845)

Net Savings (kWh/yr)

5,552

7,540

5,190

6,307

2,650

Net Savings/sq.ft.

2.7

4.7

3.2

3.9

1.7

Just One More Thing . . .

Any Questions?

Comments?

32

The Impact of Climate on HSPF

01

2345

6789

Cli

mat

e A

djus

ted

HSP

F


Rated HSPF = 7.1 Rated HSPF = 8.0

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The Impact of Controls on HSPF

0

1

2

3

4

5

6

7

8

Con

trol

Adj

uste

d H

SPF



34

Impact of Improper Commissioning on HSPF

0

1

2

3

4

5

6

7

8

Com

mis

sion

ing

Adj

uste

d H

SPF



35

Cumulative Impact on HSPF

0

1

2

3

4

5

6

7

Cum

ulat

ive

Adj

uste

d H

SPF



1 air source heat pumps potential changes in the rtf’s specifications & savings estimates and...

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