Experimental investigation on waste heat driven activated carbon-methanol adsorption cooling system

This paper presents design and fabrication of an adsorption refrigeration system working with activated carbon-methanol and coupled to the exhaust system of a multi-cylinder turbo-charged diesel engine. We have also carried out experiments to study the cycle time, refrigeration effect and COP of the cycle. This paper is reported of the original experimental data obtained from experimentation of a real adsorption refrigeration setup. We have studied and reported the effects of minimum bed temperature (T1) and maximum bed temperature (T3), the two most important parameters influencing the performance of an adsorption refrigeration system. From experimental result it is observed that the maximum temperature (T3) of the cycle should be kept as high as possible to generate higher volume of methanol from the activated carbon and, hence, higher refrigeration effect and COP. Since, the temperature of hot water circulated through the desorption bed has been restricted to 90 °C, it takes long time duration to achieve T3 above 80 °C and hence, during the experiment, the maximum temperature of the bed (T3) has been limited to 80 °C. It is also observed that the minimum temperature of the bed (i.e., the temperature of the bed after end of adsorption) (T1) should be kept as low as possible to optimize COP of the cycle. The experimental results show that, for T1 of 30 °C and T3 of 80 °C, the maximum refrigeration effect is 1519.41 kJ per cycle for the given configuration of the refrigeration system and the cycle COP is 0.21. Uncertainty analysis predicts that variation of experimental COP varies between ±6.59%. This paper also presents different practical problems that faced by the authors during fabrication of the setup, for the benefit of the future researchers. The study also aims to comment on the capability of meeting the air-conditioning requirement of a vehicle by the waste heat associated with exhaust gases only, without requiring any extra power from the engine, thereby reducing fuel consumption and environment pollution.