Performance analysis of an innovative multimode, multisalt and multieffect chemisorption refrigeration system



The conceptual design of an innovative multimode, multisalt and multieffect solid-gas chemisorption refrigeration system with evaporation and resorption processes is presented. In the proposed system, both the evaporation heat of the refrigerant during adsorption process and the reaction heat of the low-temperature salt during resorption process are employed to provide useful cooling. The reaction heat of the high-temperature salt is recovered for the regeneration process of the middle temperature salt. The presented system has the distinct advantage of larger cooling capacity per unit of heat input in comparison with other types of sorption refrigeration systems, based exclusively on evaporation or resorption. To identify the expected COP of the proposed system, two groups of working pairs containing metal chlorides and ammonia were analyzed. The ideal coefficient of performance (COP) can be improved by more than 59 to 169% if compared to the COP obtained with other kinds of cycle. When the sensible heats of the reactant, the refrigerant and the metallic part of the reactors are considered in the calculation of the COP, this figure can reach values between 0.91 and 1.80, according to the salts employed and the mass ratio between the metallic part of the reactor and the salt. © 2007 American Institute of Chemical Engineers AIChE J, 2007