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The paper deals with potential augmentation of the present R134a automotive air conditioning system with the intent to lower its total equivalent warming impact (TEWI) which is a source of concern from the standpoint of environmental benignity of the system. It is identified that the most effective augmentation strategy includes (1) increase in compressor isentropic efficiency, (2) increase in condenser effectiveness, (3) decrease in lubricant circulation through the system, (4) decrease in air side pressure drop in evaporator through improved condensate management, (5) increase in condenser airflow, (6) decrease in air conditioning load via permissible increase in the amount of recirculated air through the passenger compartment and (7) reduction in direct emission of R-134a from the system through conservation and containment measures. The effect of each of these augmentations on the coefficient of performance (COP) of the system is quantified in a rigorous fashion.

The focus of the present paper is the energy efficient automotive air conditioning system, which ipso facto is also environmentally friendly from the standpoint of global warming impact. Two efficiency enhancement strategies are presented - one entailing the use of judicious amount of recirculated air and another relying on reduction in the amount of reheating of the chilled air employed in the conventional system. The first strategy, referred to as the air inlet mixture strategy, reduces the air conditioning load by mixing proper amount of recirculated air with the outside air. The second strategy, referred to as the series reheat reduction strategy, reduces reheating of chilled air under low to moderate load conditions. Analytical relations are presented for the determination of reduction in air conditioning load due to mixing of outside air with varying amounts of recirculated air as well as due to reduction in the series reheat.