Influence of bed temperature on performance of silica gel/methanol adsorption refrigeration system at adsorption equilibrium

This paper presents a thermodynamic model for predicting the cooling performance of a single-bed single-stage silica gel/methanol adsorption refrigeration system. Solar heat was collected through flat plate collectors and then stored in a hot water tank. Desorber bed was heated by the hot water from the hot water tank. The temperature of the desorber bed was varied from 65 degrees C to 85 degrees C, and its effect on system performance was observed. A numerical model was developed on the basis of mass and energy balance equations, adsorption equilibrium, and kinetic equations (Dubinin-Astakhov equation) for predicting the performance of the adsorption refrigeration system under the said conditions for four major parts (adsorber, desorber, condenser, and evaporator). A programing code was written in FORTRAN for solving these equations under pre-defined material properties, and the simulation result was observed. A refrigeration effect of 577 kJ with a coefficient of performance (COP) of 0.38 could be produced for a maximum bed temperature of 90 degrees C, which was restricted up to 90 degrees C because after this temperature, the input increases more than the refrigeration effect, and COP values reduce due to a reduction in desorption mass.