Performance comparison and optimal parameters evaluation of solar-assisted NH3–NaSCN and NH3–LiNO3 type absorption cooling system

Abstract

This paper represents the detailed thermodynamic study to compare the performance of solar energy-assisted ammonia–sodium thiocyanate (NH3–NaSCN) and ammonia–lithium nitrate (NH3–LiNO3) absorption cooling system coupled with various solar collectors. A 15-kW absorption cooling system at evaporator temperature − 5 °C is considered and analyzed integrated with flat plate collectors (FPC), evacuated tube collectors (ETC), flat plate with compound parabolic collector reflectors and parabolic trough collectors (PTC) connected with storage tank to operate the absorption system. In this study, minimum generator (cut-off) temperature to operate the system is evaluated for both NH3–NaSCN and NH3–LiNO3 working pairs. Analysis of variance is performed to find out most critical operational parameters for cut-off temperature. In addition, the influence of heat source temperature on energetic, exergetic and economic aspects of systems is depicted. Exergetic optimization of each system estimated the required optimum collecting area for cooling. Required capital cost of solar collector at optimized area is also evaluated. The performance comparison from thermodynamic perspectives shows that NH3–LiNO3 coupled with ETC is superior to NH3–LiNO3 coupled with FPC. NH3–LiNO3 VARS coupled with PTC exhibited 23% higher value of optimized cost and 0.7% higher value of $$\eta_{{{\text{II}},{\text{system}}}}$$ in comparison with NH3–LiNO3 integrated with ETC. Key performance indicator is evaluated for the selection of optimum system. On the basis of key performance indicator, NH3–LiNO3 system coupled with ETC is recommended by considering thermodynamic and economic criteria.