First and second law analysis of ammonia/salt absorption refrigeration systems

Ammonia/LiNO3 and ammonia/NaSCN absorption refrigeration cycles are alternatives to ammonia/water cycles for refrigeration applications at temperatures below 0 °C. They exhibit higher coefficient of performance (COP) values and do not require purification of the refrigerant vapor. Entropy data for such solutions calculated using their most recently published thermophysical property data; we study and compare the cycles thermodynamically. The simulation results are used to examine the influence of various operating parameters on performance and the possibility of crystallization in these cycles. It is shown that, for low generator temperatures, ammonia/LiNO3 cycles have better performance. For high generator temperatures, ammonia/NaSCN cycles have better performance, but the range of allowable generator temperatures is quite limited for this mixture.