Dynamic Performance Investigation of Single-Effect NH3 + LiNO3 and NH3 + NaSCN Solar Cooling Cycles: A Case Study for Western Indian Climate

Abstract

This article compares the dynamic behavior of solar-assisted novel salt-based ammonia/sodium thiocyanate (NH3 + NaSCN) and ammonia/lithium nitrate (NH3 + LiNO3) single-effect absorption refrigeration cycles. An evacuated tube collector (ETC) is attached with fully mixed hot water storage tank to power the absorption system. Variations in ambient conditions are determined for Gujarat Region of India and their effects on absorption cycles are quantified throughout the days for the months of April to September. System performance is investigated and compared on terms of coefficient of performance (COP), refrigeration capacity, efficiency and solar COP (SCOP). At same operating conditions, it is found that the NH3 + LiNO3 cycle can achieve much lower evaporator temperature (−13.1 °C) then NH3 + NaSCN cycle (−7.5 °C) and maximum possible COP for NH3 + NaSCN cycle is 0.73 and 0.68 for NH3 + LiNO3 cycle. The working limit of NH3 + LiNO3 cycle is wide ranging and narrow for NH3 + NaSCN cycle due to high crystallization possibility. SCOP varies from 0.18 to 0.43 for NH3 + NaSCN cycle and 0.17 to 0.39 for NH3 + LiNO3 cycle over the period of 6 months. Based on these findings, the suitable working cycle is justified.