Exergy performance of a wellbore heat exchanger coupled with a ORC plant. Comparison of two different case studies

This paper analyses the use of a WBHX plant coupled with an ORC power plant in two different case studies: the depleted geopressurized oil field of Villafortuna Trecate and the magmatic area of Campi Flegrei. A comprehensive thermodynamic assessment of the WBHX – ORC plant has been carried out analysing each component, including the cooling tower and ancillary equipment. Different organic fluids have been tested in order to find the most advantageous in the two different cases. The concept of exergy, which is the maximum work output that could be obtained from a system, has been used to compare the performance of two case studies, assessing thermodynamic losses. Results show the relevance of the ancillary system in the assessment of system feasibility that may result in the actual limiting factor for geo-power production.