Vapor absorption system powered by different solar collectors types: Cooling performance, optimization, and economic comparison

Abstract

The current article presents the comprehensive thermodynamic modeling to compare the performance and optimization of single-stage LiCl-H2O and LiBr-H2O type absorption cooling system integrated with different solar collector types for the Gujarat, India. A 10 kW system at 7°C is analyzed which includes four different solar collectors (flat-plate collectors, parabolic-trough collectors, flat plate with compound parabolic collector reflectors, and evacuated-tube collectors) attached with insulated thermal storage tank to power the LiCl-H2O and LiBr-H2O vapor absorption system. The study investigated the effect of heat source temperature on performance aspects of systems. Optimum heat source temperature corresponding to energetic and exergetic aspects for LiCl-H2O pair is found to be lower in comparison to LiBr-H2O pair for all collectors type system. The examined performance parameters are exergetic efficiency, coefficient of performance, and area of collector. Exergetic optimization of each system estimated the required optimum collecting area for cooling. At optimum collector areas, capital cost is evaluated. Differentiation between optimized systems determined that evacuated-tube collectors-based technology is most economic and from exergetic point-of-view, parabolic-trough collectors is recommended. For effective comparison and conclusion, key performance indicator is evaluated to select optimum collector and working fluid pair from both thermodynamic and economic criteria.