C A L I F O R N I A E N E R G Y C O M M I S S I O N 2013 Building Energy Efficiency Standards Residential Zoned AC Discussion August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N Zoning Proposal Status CEC Staff Proposal Originally sponsored by the California Statewide Utilities Codes and Standards Program as a Codes and Standards Enhancement (CASE) study CASE study authors –Bruce Wilcox, P.E. –John Proctor, P.E. Proctor Engineering Group, Ltd. –Rick Chitwood, Chitwood Energy Management, Inc August 18, 20112

C A L I F O R N I A E N E R G Y C O M M I S S I O N 3 3 Agenda Importance of AC in California California cooling climate Other AC improvements Why zoning improvements Magnitude of problem and savings Laboratory testing of bypass Review of field studies Zoning Proposal Recap August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N 4 Why Air Conditioning is Important August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N 5 California Cooling Climate Features –high daytime dry bulb temperatures –big solar gains every day –low relative humidity –low nighttime temperatures Results –sensible capacity and EER at high outdoor temperature are important –dehumidification is not useful August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N 6 Staff Proposed AC Improvements Higher solar reflectance roofing Lower SHGC windows (from 0.4 to 0.25) Increased wall insulation in all zones Insulation quality inspections Whole house fans Roof deck insulation Increased attic duct insulation Mandatory AC minimum air flow Improved zonal control systems August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N 7 Why Zoning Improvements There are a lot of unimproved zoning systems in new California homes Unimproved multi-zone ducted systems have significantly lower energy efficiency –Laboratory tests by Carrier –Field tests in new California homes Many alternative zoning approaches can deliver equivalent efficiency Zoning system improvements are cost effective. August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N 8 Zoning Code Change Philosophy Multi-zone systems are fine But Multi-zoned systems should deliver the same (or better) energy efficiency as single zone systems ) August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N 9 12% of the Ducted Systems are Dampered Multi-Zoned Dampered Zoned Split10 (1Heat Pump) Single Split28 (not Zoned) Multiple Split17 Ducted Hydronic w AC11 Heat Pump5 (not Zoned) Package6 Furnace Only3 Total80 August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N 10 Dampered Multi-Zone Systems have Low CFM per Ton and High Cooling Fan Power per CFM August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N 11 Average Energy Impact In typical homes with dampered multi-zone systems: –Air Conditioning SEER and EER are degraded by 17% –Furnace AFUE is degraded by 4.4% August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N Effect of Bypass and Zoning Flow in SEER Terms August 18,

C A L I F O R N I A E N E R G Y C O M M I S S I O N Eliminate Bypass and Obtain a Minimum Airflow August 18,

C A L I F O R N I A E N E R G Y C O M M I S S I O N 14 Carrier Laboratory Testing of Bypass August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N 15 Carrier ASHRAE Paper Literature Review Papers cited by AHRI to support the zoning performance credit –“All but one study employed variable or two speed equipment.” –“… the homes were unoccupied and zone separation (closed doors) was maintained throughout testing caused energy losses to be minimized. Thus, the documented field studies could be considered a ‘best case scenario’ in terms of energy savings.” August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N 16 Code Change Proposals Eliminate bypass ducts Mandatory airflow and fan Watt verification in all zonal cooling modes (the airflow and Watt draw mandate also apply to single zoned systems) Delete the current zonal AC performance compliance credit. August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N 17 Chitwood’s Redding, California Showcase Home With 4 zone ducted AC system that meets the proposed requirements. August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N 18 Zoned A/C Literature Review Study Author(s) Energy Use Compared to Not ZonedNotes HeatingCooling Kenney & Barbour 148% ↑ Central with no set back, Zoned with 15 hours 5°F set back in bedrooms, Basement included 76% ↓71% ↓ Central with no set back, Zoned with 15 hours 5°F set back in bedrooms, Basement excluded, Setback recovery problem, Constant air circulation in cooling Oppenheim (from Kenney & Barbour) 135% ↑ No temperature set up Oppenheim/ASHRAE % ↑ Central with single speed. Zoned with two speed compressor, variable speed furnace, 84% ↓ Central with single speed constant setpoint. Zoned with two speed, variable speed furnace, 15 hour 10°F temperature set up in one zone, 9 hour 10°F set up in the other two zones August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N 19 Zoned A/C Literature Review Study Author(s) Energy Use Compared to Not ZonedNotes HeatingCooling Oppenheim/ASHRAE zones 107% ↑ Central with single speed furnace & burner, 8-hour 12°F setback. Zoned with variable speed and modulating furnace, 10 hour 12°F nightime setback on bedroom zones plus 8-hour 12°F daytime setback all zones. 3 zones 88% ↓ Central with single speed furnace & burner, 8-hour 12°F setback. Zoned with variable speed and modulating furnace, 22 hours continuous setback on bedroom zones, 8-hour 12°F setback in remaining zone. Leslie & Kazmer w Basement 116% ↑ Central with no furnace modulation, 8 hour 12°F setback everywhere. Zoned with furnace modulation, 14 hour 12°F setback in bedrooms, 15 hour 12°F setback in basement, 8 hour 12°F setback in remainder. w/o Basement 100% ↔ Same as above – no basement Heflin & Keller 118% ↑113% ↑ 41% bypass Temple 106% ↑ No bypass, no setback August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N 20 Zoned A/C Dampered Multi-Zone Air Conditioning Impact Bypass and Supply CFM (New California Home Field data) August 18, 2011

C A L I F O R N I A E N E R G Y C O M M I S S I O N 21 Zoned A/C Bypass Effect on Capacity ACCA Zoning Manual (in draft) Compared to Median Field Unit August 18, 2011