A conceptual design and performance analysis of a triple-effect solid–gas thermochemical sorption refrigeration system with internal heat recovery

A conceptual design of a triple-effect solid–gas thermochemical sorption refrigeration system using three kinds of reactive salts and ammonia as working pairs is presented. In the proposed system, two internal heat recovery processes were employed to enhance the energy utilization efficiency. The adsorption heat of a high-temperature salt was recovered for the regeneration process of a middle-temperature salt, while the adsorption heat released by the middle-temperature salt was used to regenerate a low-temperature salt. The presented sorption refrigeration system can produce three cooling-effects in one cycle, at the expense of only one heat input at high temperature. The coefficient of performance (COP) of the system can be improved by 146–200% compared to that obtained with a conventional sorption refrigeration system. When the sensible heats of the reactant, the refrigerant and the metallic part of the reactors were considered, theoretical results showed the calculated COP employing the triple-effect sorption cycle varied between 0.75 and 0.97 with the mass ratio between the metallic part of the reactor and the reactive salt.