Heat Pump Research Project

Sponsored by the

Heat Pump Working Group

June 7, 2005

Project Goals

1. Assess energy use and savings from heat pumps installed under C&RD/ConAug and EWEB.

2. Assess base case installation practices.

3. Assess heat pump performance under laboratory conditions to identify optimal settings.

4. Assess the general approach of installers to control, sizing and performance issues, and of manufacturers to new technologies, etc.

Billing Results

EWEB Billing Analysis Results

C&RD / ConAug Billing Analysis Results

All Cases NAC Saved with 90% C.L.

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

kWh

/ye

ar

Revised Results Previous Results

Billing Analysis Results by System Type

All Cases NAC Saved with 90% C.L.

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

kWh

/ye

ar

SF Sqft with 90% C.L. by Systype, n= 470

0

500

1,000

1,500

2,000

2,500

3,000

kW

h/y

ea

r

Billing Analysis Results by Building Type

C&RD MH Cases NAC Saved by System Type with 90% C.L., n= 124

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

10,000

Heat P

ump

FAF

w/CAC

FAF

w/oCAC

Zona

lAll S

ysTy

pes

All C&RD M

F

kWh

/yea

r

C&RD SF Cases NAC Saved by System Type with 90% C.L., n= 549

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

Heat P

ump

FAF

w/CAC

FAF

w/oCAC

Zona

lAll S

ysTy

pes

All C&RD S

F

kWh

/yea

r

Billing Analysis Results by Vintage

SF NAC Saved with 90% C.L. by Vintage Bin, n= 523

0

1,000

2,000

3,000

4,000

5,000

6,000

1 2 3

All C&RD

kW

h/y

ea

r

MH NAC Saved with 90% C.L. by Vintage Bin, n= 114

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

1 2 3

All C&RD

kWh

/yea

r

Legend:

1 Pre 19812 1981 – 19943 Post 94

Realization Rates by Program Year Base

Prog Year

Area n Gross NAC

kWh/yr

Net NAC

kWh/yr

90% CI

Antici-

pated

kWh/yr

RR

2002-2003

Zone 1 518 4,698 4,584 490 7,288 63%

Zone 3 318 3,795 3,681 590 6,815 54%

All C&RD

836 4,354 4,240 382 7,108 60%

Realization Rates for C&RD Calculator, Initial

C&RD Billing Analysis

Unadjusted AdjustedkWh kWh R.Rate kWh R.Rate

2003Zone 1 6563 3838 0.585 4359 0.664Zone 2 6464 3432 0.531 3681 0.569

2005Zone 1 5478 3838 0.701 4359 0.796Zone 2 5456 3432 0.629 3681 0.675

Realization Rates, Revised

Realization RatesMeasure

Sector Year FAFw/ AC FAFw/oACHP UpgradeZonalManufactured Homes 2003 66% 71% 218%

2005 70% 118% 215%

Single Family Homes 2003 60% 70% 489% 84%2005 69% 83% 254% 129%

kWh Savings estimates

Savings: C&RDMeasure

Sector Year FAFw/ AC FAFw/oACHP UpgradeZonalManufactured Homes 2003 5613 6654 1773

2005 5289 4005 1798

Single Family Homes 2003 8054 7010 976 34232005 7035 5905 1879 2243

Savings: Billing AnalysisMeasure

Sector Year FAFw/ AC FAFw/oACHP UpgradeZonalManufactured Homes 2003 3692 4713 3860

Single Family Homes 2003 4858 4880 4773 2890

Laboratory Results

HSPF: Fixed Orifice & TXV

Purdue FEO, Zone 4 (blue), Zone 6 (red)

H

SP

F

Air Flow Rate (scfm)500 1000 1500 2000

6

7

8

9

10

70

70 70

100

100100

130

13013070

7070

100

100 100

130

130130

Purdue TXV, Zone 4 (blue), Zone 6 (red)

H

SP

F

Air Flow Rate (scfm)500 1000 1500 2000

6

7

8

9

10

70

7070

100

100100

130

130 13070

7070

100

100

100

130

130 130

H

SP

F

Charge (%)60 80 100 120 140

6

7

8

9

10

800 800 800

13001300 1300

1700

1700

1700800

8008001300

13001300

1700

1700 1700

H

SP

F

Charge (%)60 80 100 120 140

6

7

8

9

10

800 800800

13001300

130017001700 1700

800 800 800

1300

1300 1300

1700 1700

1700

Summary of Lab Results

• Impacts of refrigerant charge minimal except at very reduced levels (70% of specification)

• Impacts of air flow also limited to cases with very low air handler flow (less than 300 CFM/ton).

• Low air flow appears to occur in about 25% of “base case” installation practice

• TXV improves overall performance but has minimal impacts on the effects of low charge and low air flow

• Cd higher than modeling assumptions for fixed orifice, lower than assumption for TXV

• Defrost degradation factors largely stable at values near the modeled and manufacturer’s assumptions.

Field Data Summary

Field Study Overview

• 160 field sites in 4 regions (Central Oregon, Kitsap Peninsula, Clark Co., Yakima/Walla Walla) started September 2004

• “Base case” sites, chosen at random to represent non-PTCS installations– Combine field findings with billing data to recalibrate

performance assumptions used in RTF calculations

• On-site review consists of two visits– Duct/house review (complete)– Heat pump review by service tech. (110 sites now in,

additional 15 sites expected)

Site Selection

• Sites selected via random telephone dial to have air-source heat pump and be within appropriate utility territory

• Sites might have basements/interior ducts• Clark County chosen vs. Portland because of paucity

of HPs in PDX Pacific Power svc territory– Clark actually has HP inspection program so non-typical vs

other areas

Key Audit Outputs(house/duct)

• House heat loss rate (UA)– Integral part of modeling house performance vs bills– Includes infiltration component (blower door test)

• System airflow (CFM)– System capacity & efficiency

• Duct system insulation and leakage– System operating pressures also measured

• Duct leakage fraction (%)– Effect on overall delivery efficiency/energy use

• Homeowner interaction with system (via survey)

Key Audit Outputs (heat pump review)

• HP control strategy – Indoor thermostat type, setting and staging– Outdoor thermostat presence, setting and operation– Compressor low ambient cut out

• Refrigerant charge level

Building Characteristics – Heat Loss Rate

.2.3

.4.5

.6U

A p

er s

q.ft.

Pre-76 76-80 80-86 86-92 92-2000 2000+

Blower Door Results

– Median ACH50 is 7.6 for 149 clean cases; mean is 8.3

– This converts to median ACHnat of 0.38

– Highest ACH50 19.0

– Lowest ACH50 1.60.0

5.1

.15

.2.2

5F

ract

ion

0 5 10 15 20ach50

Blower Door Results by Vintage Bin

05

1015

20B

D r

esul

ts a

t 50

pa

Pre-76 76-80 80-86 86-92 92-2000 2000+

Duct Leakage Fraction (all sites)

0.1

.2.3

.4.5

Leak

age

frac

tion

Nonzero RLF omitted

Return leak fraction Supply leak fraction

Duct Leakage by Vintage Bin0

.1.2

.3.4

.5S

uppl

y le

ak fr

actio

n

Pre-76 76-80 80-86 86-92 92-2000 2000+

0.1

.2.3

.4R

etur

n le

ak fr

actio

n

Pre-76 76-80 80-86 86-92 92-2000 2000+

Supply Side Return Side

Supply vs. Return Leakage

0.0 0.1 0.2 0.3 0.4 0.50.0

0.1

0.2

0.3

0.4

0.5

Return Leakage Fraction

0.0 0.1 0.2 0.3 0.4 0.5

Supp

ly L

eaka

ge F

ract

ion

0.0

0.1

0.2

0.3

0.4

0.5Supply vs. Return Duct Leakage Fraction

System Fan Flow

• Median flow is 340 CFM/ton (n=126)

• Lower quartile is <=292 CFM/ton

• ECM cases (n=21*), median flow is 338 CFM/ton*final # will be larger

Airflow Distribution 0

.05

.1.1

5.2

Fra

ctio

n

200 300 400 500Indoor unit CFM/ton

System airflow by size of outdoor unit

200

300

400

500

CF

M fa

n flo

w p

er to

n

1.5 2 2.5 3 3.5 4 5

Tons

Refrigerant Charge Evaluation

• Review predominantly done in swing seasons– Heating season evaluation

combined tech’s review of operating pressures and sensible split in context of ambient temp., system airflow, coil match

• About 1/3 of systems evaluated in cooling only mode or in addition to heating mode– Superheat/subcooling

evaluation

Charge Results

• 60% of cases evaluated as having correct charge

• 28% of cases evaluated as being overcharged

• 10% of cases evaluated as being undercharged– 2 had serious leaks (no

refrigerant)

Refrigerant Charge Digest

• Over/undercharge amounts likely under-reported vs weigh-in approach

• However, cases of severe undercharge were very limited

• ½ of overcharged cases had an accumulator• 2/3 of remaining overcharged cases were units with

Trane compressors or scroll compressors

Heat Pump Efficiency7

7.5

88.

59

9.5

HS

PF

Bend Clark Kitsap Yakima

77.

58

8.5

99.

5H

SP

F

1.5 2 2.5 3 3.5 4 5

HSPF by Region HSPF by Equipment Size

HVAC Usage(from median low bill analysis of 124 bills)

010

,000

20,0

0030

,000

Bend Clark Kitsap Yakima

02,

000

4,00

06,

000

8,00

0

Bend Clark Kitsap Yakima

Heating - Annual kWh Cooling - Annual kWh

Normalized Heating Load by Vintage and Region

02

46

810

Pre-76 76-80 80-86 86-92 92-2000 2000+

Heating - Annual kWh/sf Total Usage - Annual kWh/sf

010

,000

20,0

0030

,000

40,0

0050

,000

Bend Clark Kitsap Yakima

Normalized Heating Usage0

510

1520

25

No Wood Wood

Region No Wood

Wood Total

Bend 64.86 35.14 100

Clark 59.38 40.63 100

Kitsap 36.84 63.16 100

Yakima 66.67 33.33 100

Total 56.85 43.15 100

Impact of wood – Annual kWh/sf Percentage of Sample Using Wood

Modeled Duct Efficiency(efficiency of 1 is perfect ducts)

.5.6

.7.8

.9

Bend Clark Kitsap Yakima.5

.6.7

.8.9

Pre-76 76-80 80-86 86-92 92-2000 2000+

By Region By Vintage

Duct Insulation0

5010

015

020

025

0to

tal U

A o

f sup

ply

duct

s

0 20 40 60 80 100retua

05

1015

20

Pre-76 76-80 80-86 86-92 92-2000 2000+

Supply vs. Return UA R-Value of Supply Ducts

TXV Summary (Outdoor Unit)

50%

35%

61%67%

32%

0%

10%

20%

30%

40%

50%

60%

70%

80%

overall Bend Clark Kitsap Yak/WW

TXV Summary (Indoor Unit)

64%70%

81%

38%

63%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

overall Bend Clark Kitsap Yak/WW

Thermostat/Homeowner Interaction

• ~80% of systems have programmable stats…• ~1/3 of occupants say they understand their

thermostat and/or like how it keeps their house comfortable

• ~1/3 say they tolerate their thermostat (but wish they understood it better)

• ~1/3 have thrown up their hands and use the HOLD feature

Controls: Indoor Thermostat

• 78% programmable• Median heating

setpoint: 70 F• Median setback: 65 F• 55% of systems with

setback > 5 F– Estimated 75% of

programmable stats have adaptive recovery

Controls: Outdoor Thermostat

• About 35% of sites visited had an operating ODT (75% of Clark sites have ODT)

• Average setting 40° F• About 2/3 of sites without

ODTs had the extra wires needed to install one without fishing new wire

• Only 15% of systems had elements on in Stage 1 heating– Median on-time 5 minutes

Market Actor Interviews

HVAC Installer Interviews(detailed results)

• 32 shops throughout region in urban, suburban, rural areas (29 full interviews)

• Shops range from 2 trucks to 30, median of 6

• Median 50% new construction

• Participants install all major (and some secondary) brands of equipment

• Almost all participants report use of non-intuitive heat pump and duct sizing tools (Manual J, Manual D, etc.)

• Wide range of experience with utility, state, national incentive/marketing campaigns and installation procedures

Technician Certification

Percentage of Respondents

0 5 10 15 20 25 30 35

Per

cent

age

of T

echn

icia

ns

0

20

40

60

80

100NATE-Certified Technicians

Installer System Sizing Criteria

Percentage of Respondents

0 10 20 30 40 50 60

Both

Cool

Heat

Typical Sizing Priority

Percentage of Respondents

0 10 20 30 40 50 60

Cool

Heat

Sizing Priority When Loads Differ

Characteristics of Efficient Line

Percentage of Respondents

0 10 20 30 40 50 60 70 80

HS

PF

7

8

9

10

11

12HSPF of Efficient Line

8.0

9.5

9.85

10.5

Percentage of Respondents

0 10 20 30 40 50 60 70 80S

EE

R

8

10

12

14

16

18

20SEER of Efficient Line

17

15

14

13

12

11

Installation Characteristics - TXVs

Percentage of Heat Pump Installations

0% 20% 40% 60% 80% 100%

Perc

enta

ge o

f R

espo

nden

ts

0

10

20

30

40

50

TXV on the Outdoor Coil

Percentage of Heat Pump Installations

0% 20% 40% 60% 80% 100%

Perc

enta

ge o

f R

espo

nden

ts

0

10

20

30

40

50

TXV on the Indoor Coil

Availability/cost of Outdoor Unit TXV

Percentage of Respondents

0 10 20 30 40 50 60E

stim

ated

Cos

t ($/

Uni

t)

0

100

200

300

400

500Cost of Field-Installed TXV

Percentage of Respondents

0 10 20 30 40 50 60

Perc

enta

ge o

f U

nits

0

20

40

60

80

100Factory Equipped TXV

Acceptance of TXV Technology

Percentage of Respondents

0 20 40 60 80 100

Negative

Neutral

Positive

Unsure/Don't Know

General Opinion of TXV Technology

Outdoor Thermostat/Low Ambient Cutout

Percentage of Respondents

0 20 40 60 80 100

No

Often

Seldom

Low Ambient Cut Out Enabled?

Percentage of Respondents

0 20 40 60 80 100

No

Yes

Outdoor Thermostats Typically Installed?

Most respondents set at 40° F

All “often” cases in TriCities/Yakima

All “seldom” cases as above or Mid-Columbia

Installation Characteristics – Aux Heat

Percentage of Respondents

0 10 20 30 40 50 60 70 80

Never

Often

Seldom

Element wired in first stage heating?

Out of 7 cases answering “seldom” or “often”, 5 In Zone 2 (E Wash or Boise)

Installer Target System Airflow

Percentage of Respondents

0 10 20 30 40 50 60 70 80

Air

flow

Per

Ton

300

350

400

450Preferred Airflow per Ton

R410a

Percentage of Respondents

0 5 10 15 20 25

Evacuation concerns

Guardedly optimistic

Higher duct temp

Higher pressure

Like it

More labor

Too expensive

Too new

Unimpressed

General Opinion of R410a

Percentage of Respondents

0 5 10 15 20 25

Perc

enta

ge o

f In

stal

latio

ns

0%

20%

40%

60%

80%

100%Heat Pumps Installed with R410a

PTCS

Percentage of Respondents

0 10 20 30 40 50 60 70

1 to 25

26 to 50

51 to 75

76 to 100

Percentage of PTCS-Certified Installations

Percentage of Respondents

0 10 20 30 40 50 60 70

No

Yes

Familiar with PTCS specifications?

Familiarity With Third Party Charge Checking

Percentage of Respondents

0 10 20 30 40 50 60 70

1 to 25

26 to 50

51 to 75

76 to 100

Number of Check Me Certifications

Percentage of Respondents

0 10 20 30 40 50 60 70

No

Somewhat

Very

Familiar with CheckMe/ACRx/EEnalysis Programs

Acceptance of Third Party Mechanisms

Percentage of Respondents

0 20 40 60 80 100

Aids 'upselling'

Improved data

Advantages of CheckMe and Similar Programs

Percentage of Respondents

0 20 40 60 80 100

Hard to sell

Requires 2 site visits

Too much paperwork

Disadvantages of CheckMe and Similar Programs

Energy Star

Percentage of Respondents

0 10 20 30 40 50

Never heard of

Somewhat aware

Very aware

Familiarity with Energy Star HP Efficiency Requirements

Penetration of Incentives & Tax Credits

Percentage of Installations

10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Perc

enta

ge o

f R

espo

nden

ts

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0Installations Receiving Tax Credits or Incentives

Marketing Impacts

Percentage of Respondents

0 20 40 60 80 100

No

Yes

Does lower ETO requirement make a difference in sales?

Percentage of Respondents

0 20 40 60 80 100

No

Yes

Do Incentives Impact Bottom Line?

Challenges in Explaining Tax Credits/Incentives to Customers

Percentage of Respondents

0 20 40 60 80 100

Access to information

Not difficult

Too complicated

Client Priorities

Percentage of Respondents

0 20 40 60 80 100

First Cost

Operating Cost

Both

Most Important Factor to Customer

Comments on Thermostats

Percentage of Respondents

0 10 20 30 40 50 60 70 80 90 100

Difficult to program

Touch screens much better

Perceived Trends

Percentage of Respondents

0 10 20 30 40 50

Consumer awareness

Fuel cost

Fuel selection

Improving technology

Incentives

Perceived Trends in Consumer Interest in Heat Pumps