Cycle performance analysis and experimental validation of a novel diffusion absorption refrigeration system using R600a/n-octane

Diffusion absorption refrigeration (DAR) is a promising cycle with regard to renewable energy utilization, as the cycle can operate using only a thermal energy input. This study focuses on the application of a low-global warming potential (GWP) refrigerant as a substitution for conventional ammonia refrigerant. In this study, R600a/n-octane is chosen as a novel refrigerant/absorbent pair for DAR. The cycle operation characteristics are investigated through numerical analysis, in terms of the coefficient of performance (COP) and minimum temperature. The influences of five key parameters (driving temperature, total pressure, evaporator temperature, absorber effectiveness, and solution heat exchanger effectiveness) on the COP are also analyzed. Furthermore, additional experiments are performed to validate the simulation results through comparisons with the experimental data. The variation trend of the COP shows good agreement between the simulations and experiments, and the mathematical model provides a reasonable estimation of the maximum COP. It is concluded that R600a/n-octane has significant potential for DAR application, as a maximum COP of 0.162 is achieved at a driving temperature of approximately 100 °C, making it more favorable than other low-GWP refrigerant working fluids pairs and applicable for solar cooling.