Investigation of stepwise porosity and perforated fins in finned tube adsorption bed for adsorption refrigeration

Adsorption refrigeration is a green refrigeration technology. The characteristics of its key component, the adsorption bed, directly affect the operational performance of the entire system. In this study, two novel types of structures, stepwise porosity and perforated fins, were applied to three types of conventional finned tube adsorption beds to improve heat and mass transfer. Using the finite element analysis method, the impacts of porosities and perforations were systematically evaluated to clarify the application range and development potential of this new technology. The results indicate that the overall performance of the system using a finned tube adsorption bed with an annular outer fin is better than that of a plate outer fin and annular inner fin. Stepwise porosity can help maintain the system coefficient of performance (COP) and reduce the degradation of the specific cooling power (SCP) when the finned tube adsorption bed is designed with a long fin or large fin spacing. The perforated fin structure improved the refrigeration performance of the finned tube adsorption bed. Stepwise perforation affects the values of the COP to some extent, but the variations in the value of the SCP are minor. Stepwise perforation combined with stepwise porosity might be a potential structure for further improving heat and mass transfer in the adsorption bed.