Cooling output performance of a prototype adsorption heat pump with fin-type silica gel tube module

Silica gel/water type adsorption heat pump (AHP) is considered to be a promising low-temperature heat utilization system because of its ability to utilize waste heat below 353 K and to generate cooling energy for air conditioning. However, the widespread realization of AHP system has not yet been achieved due to its large footprint, which results from the low power density of the AHP system. In order to improve cooling output performance of the AHP by enhancing heat and mass transfer rates of the adsorber, a fin-type silica gel tube (FST) module consisting of circular finned-tube heat exchanger with silica gel packed between the fins was developed in our previous work. Further, based on the numerical analysis, the optimal fin pitch and fin length of the module were proposed. In this study, a prototype AHP with the new adsorber consisting of the optimized FST modules was made and cooling output performance of this prototype AHP was investigated under various operating conditions. As a result, the ability of the AHP to continuously generate cooling energy, by utilizing a heat source of around 333–353 K, was confirmed. Further, cooling output and COP were found to increase with an increase in hot water inlet temperature. Finally, it was experimentally verified that the optimized FST module can achieve more than twice higher cooling output per unit adsorber volume than the un-optimized module.