Could Automotive HVAC Become An EPA/DOE Energy Star?

EPA/DOE energy star program has effectively improved efficiency of home air conditioners by 25% with $25 billion annual saving due to the requirement of minimum SEER 10. The population of AC powered vehicles is estimated at around 180 million. The quantity may be even larger than that of home AC. Currently automotive AC seems t o work less efficiently with estimation for EER of 5 typically. If the Energy Star program could extend into automotive AC to promote energy efficiency, the result would be a significant energy saving valued at 3.38 billion gallons of gas ($5.4 billion) annually would be resulted. To find out what caused the situation, a contrastive study has been conducted on refrigerants thermal properties, system cycling performances etc. R134a used in automobiles may not be a key factor for such a negative result, but the AC compressors may be evidently a prominent consideration. A realistic prediction for the EER rating on automotive application is 8, which would result in a $4.05 billion saving per year and a $5.4 billion if it reaches 10.