Air Source Heat Pumps

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Air Source Heat Pumps
Potential Changes in the RTFs Specifications
Savings Estimates and Their Impact on CR
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

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Why Things Are Changing PNW Climates Are
Different

• ARI performance ratings (SEER HSPF) are based
  on climates that do not match the Northwests.
• 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

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Climate Adjusted HSPF
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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 doesnt operate even when it
  has a COP above 1.0.

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Control Adjusted HSPF
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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

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Commissioning Adjusted HSPF
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Cumulative Adjusted HSPF
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SEER Doesnt 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 gt Real 6.5 SEER

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Other Factors That Are Changing RTFs 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

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Pre1980 Construction Post Weatherization Forced
Air Furnace Space Heating Use
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Post79/Pre93 Construction Forced Air Furnace
Space Heating Use
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Post92 Construction Forced Air Furnace Space
Heating Use
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Revised Estimates of Air Conditioning Loads Are
Lower (e.g.,Pre1980 Construction)
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Revised Estimates of Air Conditioning Load Are
Lower (e.g., Post92 Construction)
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However, Some Revised Estimates of Air
Conditioning Load Are Higher and Lower
(e.g.,Post79/Pre93 Construction)
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Overall Implications for CR 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
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Air Source Heat Savings Adjustments for
Post79/Pre93 FAF w/o CAC Worst Case
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Air Source Heat Savings Adjustments for Post1992
FAF w/o CAC Worst Case
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Air Source Heat Savings Adjustments for Pre1980
FAF w/o CAC Worst Case
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Air Source Heat Savings Adjustments for
Post79/Pre93 FAF w/o CAC Worst Case
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Air Source Heat Savings Adjustments for Post1992
FAF w/o CAC Worst Case
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Example 1 Pre80 Single Family w/Furnace in
Heating Cooling Zone 1
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Example 2 Post79/Pre93 Single Family w/Furnace
in Heating Zone 1 Cooling Zone 2
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Example 3 Post92 Single Family w/Zonal Heat
No CAC in Heating Zone 1 Cooling Zone 3
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Example 4 Pre80 Single Family w/Furnace w/o
CAC in Heating Cooling Zone 2
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RTF Estimates Compared to City of Richlands
Analysis
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RTF Estimates Compared to City of Richlands
Analysis
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Just One More Thing . . .

• Any Questions?
• Comments?

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The Impact of Climate on HSPF
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The Impact of Controls on HSPF
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Impact of Improper Commissioning on HSPF
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Cumulative Impact on HSPF