Conventional and advanced exergoeconomic analyses of geothermal district heating systems

• Comprehensive advanced exergoeconomic assessment of GDHSs for the first time.
• Determining conventional exergoeconomic factor to be 5.53%.
• Calculating modified exergoeconomic factor to be 9.49%.
• Deducting inefficiencies of the system components for possible improvements.

The present study deals with analyzing, assessing and comparing conventional and advanced exergoeconomic analyses to identify the direction and potential for energy savings of a geothermal district heating system in future conditions/projections. As a real case study, the Afyon geothermal district heating system in Afyonkarahisar, Turkey, is considered while its actual operational thermal data on 8 February 2011 are utilized in the analysis, which is based on the specific exergy costing method. In this study for the first time, based on the concepts of avoidable/unavoidable and endogenous/exogenous parts, cost rates associated with both exergy destruction and capital investment of the geothermal district heating system are determined first, and the obtained results are then evaluated. The results indicate that the internal design changes play a more essential role in determining the cost of each component. The cost rate of unavoidable part within the components of the system is lower than that of the avoidable one. For the overall system, the value for the conventional exergoeconomic factor is determined to be 5.53% while that for the modified one is calculated to be 9.49%. As a result, the advanced exergoeconomic analysis makes more sense given the additional information in splitting process of the components.