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Air Source Heat Pumps

Air Source Heat Pumps. Potential Changes in the RTF’s Specifications & Savings Estimates and Their Impact on C&R Discount Program Credits. Why “Things” Are Changing – New Energy Star Specifications.

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Air Source Heat Pumps

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  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

  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

  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

  9. Cumulative Adjusted HSPF

  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 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

  13. Post79/Pre93 Construction Forced Air Furnace Space Heating Use

  14. Post92 Construction Forced Air Furnace Space Heating Use

  15. Revised Estimates of Air Conditioning Loads Are Lower (e.g.,Pre1980 Construction)

  16. Revised Estimates of Air Conditioning Load Are Lower (e.g., Post92 Construction)

  17. However, Some Revised Estimates of Air Conditioning Load Are Higher and Lower (e.g.,Post79/Pre93 Construction)

  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

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

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

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

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

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

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

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

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

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

  28. 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

  30. RTF Estimates Compared to City of Richland’s Analysis

  31. Any Questions? Comments? Just One More Thing . . .

  32. The Impact of Climate on HSPF

  33. The Impact of Controls on HSPF

  34. Impact of Improper Commissioning on HSPF

  35. Cumulative Impact on HSPF

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