Experimental studies on solar assisted activated carbon based adsorption refrigeration system

Abstract

The refrigeration and air conditioning has become an integral part of today’s life in both domestic and industrial sector and is continuously growing beyond one’s imagination resulted in the price rise of fossil fuels and negative environmental impact due to the existing cooling technologies which works mainly on vapour compression principles using traditional refrigerants. This results in the emission of harmful gases which in turn causes global warming and ozone layer depletion. This has made to find the refrigeration system which is reliable, pollution free, environmental friendly and economical. In this context heat operated systems such as adsorption refrigerators run by low heat source temperatures from solar or waste heat energy are gaining significant importance for cold production. The cooling systems run by vapour adsorption principles are favourable in terms of eco-friendliness and reliability but the coefficient of performance (COP) that can be achieved is low and hence are not able to compete with the vapour compression systems which is due to the lack of technological development. Hence the research activities are still ongoing in this area to solve the environmental, technical and economic issues. The literature indicates that the adsorption refrigeration system’s performance depends upon the working pair used such as silica gel-water, activated carbon-ammonia, zeolite-water etc. and driving temperature. It is also observed that in India, research related to adsorption refrigeration is rare. Hence in the present work using activated carbon and methanol as the working pair, experimental studies are carried out on a solar assisted double bed adsorption refrigeration system to evaluate the performance under different working conditions. Results show that the lowest cool down temperature noticed in the evaporator under no load condition is 2 °C for the operated cycle time and the values of COP obtained were in the range of 0.1–0.3 for different operating parameters studied. The adsorption system is viable to produce cold even with low temperature source of heat.