Energy and Exergy Assessment of Salihli Geothermal District Heating System

Abstract

The present study undertakes an energy and exergy analysis of the Salihli geothermal district heating system (SGDHS) in Manisa, Turkey. In the analysis, actual system data obtained on 1 February 2004 directly from the system are used to assess the district heating system performance, through energy and exergy efficiencies. Energy and exergy losses within SGDHS are determined and compared (for a dead state temperature of 0?C). It is found that the exergy losses in the system are essentially due to the fluid flow and take place in the pumps and heat exchangers, as well as the exergy losses of the thermal water (e.g., geothermal fluid) and the natural direct discharge of the system. As a result, the total exergy losses account for 1.72% in pumps, 16.47% in the discharge and 23.62% in heat exchangers, based on the total exergy input to the entire SGDHS. The overall energy and exergy efficiencies of the system are found to be 53.73% and 58.20%, respectively. In addition, the efficiencies of the system elements are studied to evaluate the individual performances and performance improvement possibilities.