Energy and exergy analysis of refrigeration systems

Abstract

Energy requirement for refrigeration and air conditioning applications bears a huge share of total energy consumption around the world. Since, thermal comfort plays a very important role on the health, working efficiency and activities of all living beings, especially, temperature and humidity. In the excessively hot climates it is necessary to reduce the temperature and humidity whereas in the cold climate there is a need to increase the temperature. When the temperature drops below thermal comfort level, especially in the winter season, the heating systems are employed. In some countries, where the atmospheric temperature is very low, natural heating like solar energy is not sufficient, the heat pump and fuel fired systems are proven to be suitable heating devices. In hot climates, thermal comfort achieved through the use of air conditioning systems. The energy balance is a basic method of any process investigation, which makes the energy analysis possible, points out needs to improve the process and is the basis to develop exergy balance. Energy balance results would disclose the efficiency of energy utilization in particular parts of the process and allow comparing the efficiency and the process parameters with the currently achievable values in the most modern installations. They will also establish the priority of the processes requiring considerations, either because of their excessive energy consumption or because of their particularly low efficiency. newlineFor these reasons, the modern approach to process analysis uses exergy analysis, which provides a more realistic view of the process. The exergy analysis is the contemporary thermodynamic method used as an advanced and useful tool for engineering process evaluations. Whereas, the energy analysis is based on the first law of thermodynamics, and the exergy analysis is based on both the first and second law of thermodynamics.A literature review on different systems reveals that with regards to vapor absorption cycles, it is found that mostly the studies are car