Computer-aided conceptual thermodynamic design of a two-stage dual fluid absorption cycle for solar refrigeration

This communication presents thermodynamic assessment of a two-stage dual fluid absorption refrigeration system using H₂O---LiBr and NH₃---H₂O as working fluids at the first and second stage, respectively. Both stages are assumed to be operated with hot water available from separate solar collectors. In the cascading of two-stage absorption systems, the evaporator of the first stage produces cooling water which is circulated in the absorber of the second stage. It is found that two-stage systems can be used for the production of very low temperatures using moderate generator temperatures at the first stage. The effects of generator temperature, absorber temperature and condenser temperature on the coefficient of performance, minimum evaporator temperature and effective refrigeration produced are also presented.