Energy and exergy analysis of a modified absorption cycle: A comparative study

Detailed exergy analysis is conducted on a branched generator-absorber heat exchanger (branched GAX) cycle and the system performance is compared to that for the GAX cycle thermodynamically. By considering the physical and chemical exergies, exergy destruction in each component of the system is calculated and its contribution to the overall exergy destruction is revealed. Parametric studies are also performed to investigate the effects on the coefficient of performance (COP) and the exergy efficiency of some design variables. The results indicate better performance for the branched GAX cycle from the viewpoints of energy and exergy efficiencies. The branched GAX system, however, depends strongly on the condenser temperature which can be accounted as a disadvantage. It is observed that the branched GAX gains an advantage of about 14% in the COP and exergy efficiency for the condenser temperature of 30 degrees C, however, this advantage goes away as the condenser temperature reaches 50 degrees C. Furthermore, the total exergy destruction in the branched GAX cycle amounts to 5.17 kW, i.e., 10.6% lower than that for the GAX cycle.