Keywords: vapour absorption refrigeration, exergy destruction, exergetic efficiency, LiBr-H2O, NH3-H2O, solar power, solar energy, second law, thermodynamics
Exergetic analysis of solar powered absorption refrigeration system using LiBr-H2O and NH3-H2O as working fluids
This study provides an easy to follow description of the second law (of thermodynamics) method as applied to a single effect absorption refrigeration cycle. Two different sets of working fluids: LiBr-H2O and NH3-H2O solution are considered, and a method to calculate the entropy of both working fluids is offered. The total exergy destruction in the system as a percentage of the exergy input from the generator heating water over a range of operating temperature is examined for the system operates on both the working fluids separately. It is found that the total exergy destruction for NH3-H2O solution is significantly higher than the LiBr-H2O solution for a given generator temperature. The exergy destruction in each component and the exergetic efficiency of system operates on LiBr-H2O and NH3-H2O solution is also determined. It is shown that the exergy destructions are significantly occur in generator and absorber, and the exergetic efficiency increases significantly as absorber temperature increases.