MODELING AND SIMULATION OF A SOLAR POWERED ADSORPTION REFRIGERATION SYSTEM

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Department of Engineering

ABSTRACT
The search for renewable, eco-friendly energy source other than fossil fuels which is ozone depleting and responsible for climate change to power refrigeration systems has led to the present research. The modeling and simulation of a solar powered adsorption refrigeration system using three types of collectors (flat plate, evacuated tube, and parabolic trough collectors), with activated carbon/methanol as the adsorbent/adsorbate pair has been undertaken in this study. A study of the adsorption bed was carried out to determine the effects of generation, evaporation and condensation temperatures on the performance of the cooling system. This was then used in the optimization of the solar thermal system in the sizing of the collector area and hot water storage tank. A transient simulation of the cooling system with an evaporator temperature of 0oC and condenser temperature of 25oC was subsequently carried out with the TRNSYS software over a period of a typical year. The Flat plate collector system gave average values of refrigeration effect of 4814.83 kJ, solar coefficient of performance (COPs) of 0.024, a cooling coefficient of performance (COP) of 0.608 and a heating efficiency of 0.46. The Evacuated tube collector powered system achieved average values of refrigeration effect of 5528.05 kJ, COPs of 0.025, a COP of 0.612 and a heating efficiency of 0.61. The Parabolic trough collector powered system however gave average values of refrigeration effect of 5654.73 kJ, COPs of 0.025, a COP of 0.613 and a heating efficiency of 0.76. The three systems were able to achieve a cold room temperature of about 1oC. Some experimental results were used to validate the simulation results and they were determined to have a good level of agreement with a consistent overestimation of COP of 29.9%.