Experimental comparison of the sorption and refrigerating performances of a CaCl 2 impregnated composite adsorbent and those of the host silica gel

Abstract

In this paper, the adsorption and refrigerating performances of a composite adsorbent (S40) and its host microporous silica gel matrix (S0) are investigated comparatively in which water is used as refrigerant. The composite adsorbent is developed by impregnating the silica gel (S0) with calcium chloride. A lab-scale single-bed adsorption chiller system, functioning without any valve on its refrigerant circuit, is designed and used as test rig. The mass ratio (MR), defined as the ratio of the specific cooling power (SCP) of S40 to that of S0, is found to be higher than 2, while the COP has been improved by 25%, in average. The S40 has been tested to have, not only the capacity of adsorbing water vapour more than twice as much as the S0 does, but also, kinetically, to adsorb and desorb faster. The cycled amounts of refrigerant (CAR), calculated from measured isobaric adsorption levels, further show that the S40 can be regenerated at lower temperatures, with respect to S0.