Performans and exergy analysis with two stage NH3-H20 absorption refrigeration systems

ABSTRACTThermodynamic system analysis are used three methods. This methods are in turn in order;energy analysis (first law analysis), second law analysis methods.The objective of this study is to examine concept of exergy , to give reference information onthe performance and exergy analysis methods how to apply on refrigeration systems , actuallyhow much effective is used on the refrigeration systems.The main aim of refrigeration cycles, like all others, is to increase the cycleefficiency. Inrefrigeration cycles for increasing the cycle efficiency, superheating in the evaparator,multistage compression and subcooling in the condenser methods are used. On the other hand,the more effective arrangement for increasing the cycle efficiency is calculating theirreversibilities in the cycle and taking the necessary measures to reduce the irreversibility ratein the cycle.In this study, methods of exergy analysis will be explained, basic information on first andsecond law analysis methods. Then, basic information about refrigeration cycles are given,thermodynamic analysis will be done theoretical.In the last part of study, numerical example about two stage absorption refrigeration systemswill be done exergy analysis methods, entrophy values of the components of the cycles,exergy loses and COP value of the system are calculated and system performance will beexamined. Maximum exergy loses to be formed on generator and absorber in system.The most important conclusion of this study, COP value of the system straight balanced withefficiency of heat exchanger and heat of evaparator, reverse balanced with heat of absorberand condenser is changed.At the same time , the terms of total entropy and efficiency ofsecond law are changed reverse balanced with COP value of the systems.Keywords: Absorption , refrigeration , exergy analysis , second law , availability , ammonia-waterii