Simulation study of the heat and mass recovery on the performance of adsorption cooling systems

In this study, simulation was conducted to investigate the effect of mass recovery, heat recovery, pre-heating and pre-cooling time on the system performance of a double-bed adsorption cooling system. Pressures of different system components were considered in the simulation. The adsorbent-adsorbate pair used was silica-gel and water. The heating and cooling temperatures were selected to be 85°C and 27°C respectively. Both the adsorption and desorption phase times were set at 15 minutes. The coefficient of performance (COP) and specific cooling power (SCP) were used to quantify the performance of the system. From the simulation, the basic cycle provided COP and SCP of 0.20 and 40.9W/kg respectively. By conducting heat recovery for 120 seconds, the system COP was largely increased by 99% to 0.40 compared to the basic cycle. The SCP was also increased to 42.3W/kg. Mass recovery, however, did not have too much effect on the system performance. The COP and SCP only increased by 4.5% and 3.9% respectively when conducting mass recovery for 4.7 seconds. For conducting heat and mass recovery, the COP and SCP were increased to 0.36 and 44.68W/kg, respectively. Pre-heating and pre-cooling can also be beneficial in improving both COP and SCP. The COP and SCP were increased by 14.5% and 10.1% respectively, to 0.23 and 45.0W/kg by conducting pre-heating and pre-cooling for 50.3 seconds. The combinations of these processes were also studied. It is suggested heat and mass recovery then preheating and pre-cooling should be conducted to improve COP and SCP. The improvements showed 31.2% for COP, increasing to 0.27, and 11.9% for SCP, increasing to 45.7W/kg.