# Air Conditioning Credits in the LightDuty GHG Rule (and Beyond)
29 Jan 2011 

# Update for 2011 MACS Convention Brian Nelson - US EPA

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# Key Elements Concerning A/C Credits

 

## “ Leakage ” credits are calculated using the method described in SAE J2727 (August 2008 version)  

## “ Efficiency” credits are calculated using menu - based approach, where design/control attributes of the vehicle’s A/C system are used to determine the amount of the credit:

– For model years 2012 and 2013, only the menu is used

– For model years 2014 through 2016, the menu is supplemented by an A/C Idle Test

– The A/C Idle Test is used to measure the incremental CO2 emissions due to A/C Use, and adjust the credit amount downward if test result less than 14.9 g/min.  

## “ Off- Cycle ” credits are those which are not capture in an existing 

## test cycle or menu item

– Mfr. must justify rationale for granting an off - cycle credit for “new and innovative” technologies

– Standard test metric does not exist for off - cycle credits

# A/C Efficiency Credit Adjustment (2014 - 2016 only)

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0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

14.0 15.0 16.0 17.0 18.0 19.0 20.0 21.0 22.0 Credit Adjustment Factor

A/C Idle Test Result (g/min.) If test result is 14.9 g/min. or less, the vehicle receives 100% of the applicable A/C efficiency credit If test result is 21.3 g/min. or greater, the vehicle receives 0% of the applicable A/C efficiency credit If test result is greater than 14.9 g/min., but less than 21.3 g/min, the applicable A/C efficiency credit is adjusted downward, as a function of the test result

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# What We Finalized in the A/C Credit Menu

# Early A/C Credits

 

## Available in MYs 2009 – 2011  

## Credits determined using same methodology as used for 

## MY2012 A/C credits  

## To earn early A/C credits for vehicles in California and CAA 177 states, the manufacturer must use one of the EPA early CO2 credit Pathways that covers those vehicles  

## For vehicles outside of California and CAA 177 states, manufacturers may earn early A/C credits regardless of whether or not the vehicles are included in an early CO2 credit Pathway


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# Development of New Test Methods

 

## Have begun discussions with stakeholders to establish a framework for quantifying the power consumed by vehicle A/C 

## systems:

– Development of test methods/procedures

– Use of models to determine expected power consumption

– Verification of model results with vehicle - level testing  

## What we said in the Final Rule concerning next steps:

– “While EPA considers a test cycle that covers a broader range of vehicle speed and climatic conditions to be ideal, developing such a representative A/C test would involve the work of many stakeholders, and would require a significant amount of time, exceeding the scope of this rule. EPA expects to continue working with industry, the California Air Resources Board, and other stakeholders to move toward increasingly robust performance tests and methods for determining the efficiency of mobile A/C systems and the related impact on vehicle CO2 emissions, including a potential adapted SC03 test.”

# Future Rulemaking Proposals:

 From Heavy- Duty GHG Proposed Rule, Federal Register / Vol. 75, No. 229 / Tuesday, November 30, 2010 / Proposed Rules, page 74163: “In addition to the proposed EPA tractor- and engine -based standards for CO2 and engine -based standards for N2O, and CH4 emissions, EPA is also proposing a separate standard to reduce leakage of HFC refrigerant from cabin air conditioning systems from combination tractors, to apply to the tractor manufacturer.”  From Interim Joint Technical Assessment Report: Light - Duty Vehicle Greenhouse Gas Emission Standards and Corporate Average Fuel Economy Standards for Model Years 2017 - 2025, September 2010, page D - 5: “Our proposed approach would associate each component with a specific leakage rate in grams per year identical to the values in J2727 and then sum together the component leakage values to develop the total A/C system leakage. However, in this “percent system leakage per year” approach, the total A/C leakage score and is then divided the value by the total refrigerant system capacity to develop a percent leakage per year .” 

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# Questions/Comments? For more information, contact Brian Nelson 

# at the U.S. Environmental Protection Agency: 

# nelson.brian@epa.gov 734 - 214 - 4278
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