Investigation of non-equilibrium adsorption character in solid adsorption refrigeration cycle

Abstract

The adsorber is the key element in an adsorption refrigeration system. Its characteristic coupled with heat and mass transfer and adsorption dominats the cycle performance. In general, the velocity of adsorption in adsorber is not faster than that of heat transfer, that is, the adsorption rate does not reach the equilibrium value at each status point in real operation. The feature of non-equilibrium adsorption results of apparent different characteristic on adsorption refrigeration performance comparing with the case of equilibrium adsorption model. Based on numerical simulation, both models with equilibrium and non-equilibrium adsorption are compared with each other. The simulations condition includes various surface diffusing velocity coefficients. This paper shows the characteristic of temperature and adsorbed mass rate distribution in adsorber and some thermodynamic analysis on adsorption refrigeration cycle. It could be observed that non-equilibrium adsorption should be taken into account in adsorption refrigeration particularly for short cycle time and vacuum system.