Global Warming Impact of Automotive Air Conditioning Systems

As a prelude to the assessment of the global warming impact of automotive air conditioning, fundamental scientific facts about global warming are reviewed. A comprehensive mathematical model is next developed to quantify the total equivalent warming impact (TEWI) of the automotive air conditioning. Using this model, intensive calculations are performed to determine the TEWI of the present R-134a air conditioning system as well as the proposed alternate systems. The calculated results indicate that TEWI of the present R-134a system is higher than those of the flammable subcritical systems (R-152a, R-290 and R-717) but lower than those of the supercritical carbon dioxide system (R-744) and open air (R-729) cycle system. The calculated results show that TEWI of 303 million R-134a automotive air conditioning systems in the worldwide fleet is no more than 0.14% of TEWI of the greenhouse gases emitted annually into Earth's atmosphere due to human activity. According to the TEWI reduction cost estimates developed by the Council of Economic Advisers to the U. S. President, the cost of eliminating automotive air conditioning TEWI should not exceed $12.60 per system over its life span of 12 years. Taking cognizance of the miniscule contribution of automotive air conditioning to the global emissions and the acceptable cost to eliminate them, it is concluded that the most felicitous and cost effective solution to deal with the automotive air conditioning TEWI is to continue to improve the existing R-134a system through reduction of the refrigerant emissions and enhancement of the overall system efficiency.