Simulation and analysis of open cycle absorption systems for solar cooling

Abstract

This paper describes a performance analysis of two open-cycle absorption systems for solar cooling. The working fluid is LiClH 2O, where the water desorbs into the atmosphere and is replaceable. Both systems comprise a closed absorber and evaporator as in conventional, single-stage absorption chillers. The open part of the cycle is in the regenerator, used to reconcentrate the absorbent solution by means of solar energy. One of the systems under study has employed direct regeneration in a regenerating collector, exposing the solution simultaneously to the sun and to a stream of air. The other has employed indirect regeneration by contacting the solution with air heated elsewhere in a flat-plate collector. The analysis was performed using a code developed for modular simulation of absorption systems under varying cycle configurations and with different working fluids. The code has been modified to accommodate the features of the open-cycle systems, including the regenerating collector and the air-solution contactor. Based on specified design features, the code calculates the operating parameters in each system for a variety of conditions. The paper presents the performance curves obtained for both systems. Results indicate a definite performance advantage of the direct-regeneration system over the indirect-regeneration one.