Modeling and performance assessment of a combined geothermal-ejector refrigeration system

This study investigates the integration of an innovative combined power and cooling (CPC) system into the existing infrastructure of the DORA 1 geothermal power plant in Aydın, Turkey. Using real operational data, this research models the integration of an ejector refrigeration cycle to enhance both power generation and cooling capabilities. The proposed system utilizes waste heat from the geothermal power plant's re-injection wells, which operate at temperatures of 81.7 °C and 69.1 °C. Four environmentally friendly refrigerants (R290, R717, R600 and R1234ze) were evaluated for their performance in the refrigeration cycle. Of these, R717 and R1234ze showed superior performance, achieving the highest coefficients of performance (COPs) and exergy efficiencies. The integration of the ejector refrigeration cycle resulted in a 12 % improvement in overall energy efficiency compared to traditional power-only systems, with a maximum COP of 0.72 under optimal conditions. This study fills a significant research gap by providing a practical application of combined geothermal power and refrigeration, and provides valuable insights into the feasibility, efficiency and sustainability of such systems. The results suggest that the proposed system not only improves energy utilization, but also contributes to environmental sustainability by reducing reliance on conventional cooling methods. This research has the potential to guide future developments in the field of geothermal energy and refrigeration, promoting the adoption of integrated energy systems for improved efficiency and reduced environmental impact.