Energy and Exergy Analysis of a Compression and Absorption Chiller Coupled with Solar Energy

Abstract

The performance of a water-ammonia air-cooled absorption chiller cycle is evaluated using a low-temperature source of solar thermal energy in accordance with Tehran's climatic conditions in different working conditions. Energy and exergy analysis of an absorption chiller with computer code written in EES software is performed. Exergy analysis showed that 71% of the exergy loss in the system is related to the generator and 24% is related to the absorber. The results showed that with increasing the generator temperature to a certain temperature, the coefficient of performance increased. The generator temperature of 70 degrees at low absorber temperatures performs better than other generator temperatures. As the generator temperature rises to about 70 ℃ , the exergy efficiency increases, and then the exergy efficiency decreases with increasing temperature. As the temperature of the generator decreases, the circulation ratio increases, and at temperatures below 70 degrees, this increase is seen as exponential and so undesirable that it makes it practically impossible to use the cycle at temperatures below 70 degrees. With the other negative effects seen at temperatures above 80 ℃ to reduce the exergy efficiency, the generator temperature between 70 and 80 ℃ seems appropriate for the proposed absorption cooling system.