A review of developments in solid-vapour adsorption-refrigeration and heat-pump systems

Over the past decade there have been considerable efforts to use solid-vapour adsorption technology for refrigeration, but intensified efforts were initiated only since the imposition of international restrictions on the production and use of chlorofluorocarbons. Yet, to this date only the desiccant evaporative cooling system of the open type has achieved commercial use, predominantly in the USA. Closed-type solid-vapour refrigeration and heat-pump systems are still at the laboratory testing stage. Promising recent developments in Japan, Europe and the USA include the use of porous metal hydrides and composite adsorbents. Various analytical investigations relate to devising methods for improving system performance, such as the use of thermal wave concept. They predict considerable improvement in the performance of solid-vapour adsorption systems with cooling COP values of more than unity. This paper presents the status of solid-vapour adsorption-refrigeration and heat-pump technologies investigated by various researchers, with emphasis on salient experimental achievements.