Comparative Exergetic Analysis of Vapour Absorption Refrigeration System Using Three Different Absorbent Refrigerant Fluids: LiBr–H2O, LiCl–H2O, and NH3–H2O

The ever-increasing demand for efficient and sustainable cooling technologies has driven the need to explore advanced refrigeration systems. Vapour absorption refrigeration systems (VARS) are one such promising alternative that utilizes absorption processes to produce cooling effects. In this study, we present an exergetic analysis of VARS using three different working fluid pairs: LiBr–H2O, LiCl–H2O, and NH3–H2O. The objective of this study is to compare the exergetic performance of these fluid pairs and identify the most suitable and efficient option. The analysis is conducted through the evaluation of exergetic efficiency and exergy destruction in each of the system components with different generator temperatures, absorber temperatures, condenser temperatures, and evaporator temperatures. The thermodynamic analysis, utilizing the principles of the second laws of thermodynamics, is conducted employing the Engineering Equation Solver (EES) software and REFPROP software. It’s concluded that the LiBr–H2O refrigerant exhibits the highest exergetic efficiency of 67.2% at specific operating conditions: 5 °C evaporator temperature, 90 °C generator temperature, 50 °C condenser temperature, and 40 °C absorber temperature. Following closely, LiCl–H2O achieves an exergetic efficiency of 62.5%, while NH3–H2O attains a lower value of 46.77%. Additionally, the NH3–H2O refrigerant fluid experiences the highest generator exergy loss of 2.08 kW at a generator temperature of 80 °C. In contrast, the lowest generator exergy loss of 2.80 kW is observed for LiCl–H2O at a condenser temperature of 55 °C.