Energy and Exergy analysis of water- lithium bromide absorption systems

Absorption systems have been in the spotlight of scientists due to their capability to utilize excess energy and heat produced by other working systems. One of the inhibitory factors in using these systems is their low efficiency. This inhibitory factor has been a reason for scientists to propose different configurations for these systems. Investigation of these systems using the second law of thermodynamics could lead to understanding of the reasons behind their low efficiency. In this paper, variations of coefficient of performance and exergetic efficiency of single, double and triple effect parallel and series water-lithium bromide absorption systems with generator temperature in different evaporator temperatures are analyzed using a code written in Engineering Equation Solver (EES). The obtained results demonstrate the excellence of triple effect absorption systems in comparison to double and single effects. Exergetic efficiency increases 10 to 18 percent for each increase of complexity of system. These results also depicts the excellence of parallel systems to series ones. Also, the rate of refrigerant fluid working in the cycle to heat delivered to the high temperature generator is higher for parallel systems compared to series ones and is higher for triple effect systems.