Evaluation of solar source and ground cooling performance in three different organic rankine cycle (ORC) configurations

The performance of three different ORC configurations using R245fa was modeled comparatively in the current study. The three configurations of ORC are the basic ORC (B_ORC), the single-stage regenerative ORC (SR_ORC), and the double-stage regenerative ORC (DR_ORC). These configurations consist of traditional ORC equipment; in the regenerative, unlike the others, a feed heater is added. Secondly, the properties of all points in the configuration have been calculated analytically, and their energy and exergy efficiencies have been examined to make a detailed thermodynamic analysis. When the configurations were compared in terms of given assumptions, the total exergy efficiencies for B_ORC, SR_ORC, and DR_ORC were calculated as 10.99, 12.95, and 13.41%, respectively. Also, in terms of ORC exergy efficiency, it is 43.26, 50.03, and 51.78%, respectively. The configurations were examined in terms of some parameters affecting the performance. Then, the best operating point of the regenerative configurations was found and evaluated from an economic point of view. The soil source has been considered to supply cooling water in the ORC system’s condenser. It is suggested that the fact that the soil temperature remains constant after a certain depth is an essential factor for the cooling water requirement. In the last section of the study, annual electricity production amounts have been deduced for four provinces in different regions of Turkey. The annual total amount of electricity energy produced is 4151 kWh year−1 for Antalya, 3965 kWh year−1 for İzmir, 3286 kWh year−1 for İstanbul, and 2847 kWh year−1 for Trabzon.