Etude des transferts de chaleur et de masse dans une machine frigorifique à adsorption solaire

Abstract

The aim of this thesis is to study the influence of the constructive parameters of an adsorption bed on the performance of a two-bed adsorption chiller and on the temperature distribution of the adsorbent, the rate of the adsorbate and the pressure in the adsorption bed. In the context of the choice of the adsorbent-adsorbate couple, a very important step in optimizing the performance of an adsorption refrigeration machine, a static model of an adsorption cooling machine was developed. A FORTRAN computation code corresponding to this model has been established allowing the best choice of the adsorbent-adsorbate couple. The performance of two adsorbent bed silica gel-water adsorption chiller and the influences of its adsorbent bed dimensions, the velocity of heat exchange fluid and the adsorbent particle diameter on the transient distributions of the solid phase temperature, adsorbate concentration and the pressure are numerically examined in this study. A transient two-dimensional local thermal non-equilibrium model that takes into account both internal and external mass transfer resistances is developed to simulate the adsorption chiller considered herein. The internal and external mass transfers are predicted by the linear driving force (LDF) model and Darcy’s equation, respectively. The results of our simulations provide useful guidelines for the design of this type of adsorption chillers.