Developmens of alternative systems for automotive air conditioning - A review

Vapor-compression refrigeration (VCR) systems are still the most widely used type of automotive air conditioning (A/C) systems in spite of their high energy consumption and negative environmental effects. Although the significant amount of research conducted during the last three decades, the automotive alternative (A/C) systems are yet immature. Despite some remaining constraints only (VCR)-type of A/C systems, powered by electric energy and used in EV's, have reached the commercialization level. Also thermoelectric A/C systems powered by recovered exhaust energy and used for seat occupant cooling as well as (VCR) A/C systems powered by solar energy, are developed to the extent that they can be commercialized in the near future. Whereas the other alternative systems still suffer from many challenges that make them unable to satisfy the severe requirements of automotive air conditioning. Among those challenges: Large system size and complexity which do not realistically work in the demanding automotive environment, low coefficient of performance (below one for most of them) which prevents them from competing with the conventional (VCR) systems, high initial cost and lack of enough heat to power most of the systems. However alternative A/C systems have the advantage of being eco-friendly. A future development roadmap is presented to overcome the above-mentioned challenges.