Heat Pump Research Project
description
Transcript of Heat Pump Research Project
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