Abstract
Chlorofluorocarbon and hydrochlorofluorocarbon refrigerants have been widely used in traditional cooling systems. These refrigerants accelerate the depletion of the Earth's ozone layer. Therefore, adsorption air-conditioning technology attracted much attention recently as an alternative solution due to its advantage of environmental friendliness. This system as it powered by waste and/or solar heat can help to reduce required energy and thermal pollution. This paper presents an overview of research which have been carried out on adsorption cooling systems powered by waste heat from automobiles. Many adsorption pairs have been studied. Zeolite-water as a working adsorption pair has been widely used in automobile adsorption cooling systems. This pair has been powered by exhaust gases from the engine due to its relatively high working temperature. Silica gel-water pair has been also widely used in automobile adsorption cooling systems. It has been powered by waste heat from water coolant in the engine due to its relatively low working temperature. Results show that this technology can help in increasing overall engine efficiency and reduce thermal pollution from engines. Various modifications in adsorption cooling systems are still required. One of the bottlenecks which prevents the improvement of adsorption cooling technology is its relatively low performance compared to conventional vapor mechanical compression technologies. (C) 2015 Elsevier Ltd. All rights reserved.