Comparative Analysis of Geothermal Powered Organic Rankine Cycle for Supercritical Fluids

Abstract

Turkey's energy consumption has risen in conjunction with its economic growth over the past decades. However, approximately 70 % of the electricity demand is supplied by fossil-based fuels, which are mainly imported from other countries. Thus, it became very important for the country to find alternative ways of meeting the energy requirement. Due to its geographical position, the renewable energy potential of Turkey is fairly well, which is currently contributing to the energy generation but not at the desired level. One of them is the geothermal energy that Turkey has many geothermal areas, and they are relatively appropriate for electricity production. This study aims to investigate the performance of a geothermal based transcritical Rankine cycle for various supercritical working fluids. The geothermal reservoir is located in the west part of Turkey, and the geothermal water temperature is about 156 °C. Using the actual data, comparative thermodynamic analyses are carried out for determining the best working fluid. Results show that the highest power generation rate is calculated for the cycle using R170 with 6125 kW, followed by R744. In addition, the highest irreversibility is calculated for R125 with an exergy destruction rate of 8397 kW.

Keywords

• Geothermal energy,ORC,supercritical,thermodynamic analysis

Evaluation of Transcritical Rankine Cycle Driven by Low-Temperature Geothermal Source for Different Supercritical Working Fluids

Abstract

Turkey's energy consumption has risen in conjunction with its economic growth over the past decades. However, approximately 70 % of the electricity demand is supplied by fossil-based fuels, which are mainly imported from other countries. Thus, it became very important for the country to find alternative ways of meeting the energy requirement. Due to its geographical position, the renewable energy potential of Turkey is fairly well, which is currently contributing to the energy generation but not at the desired level. One of them is the geothermal energy that Turkey has many geothermal areas, and they are relatively appropriate for electricity production. This study aims to investigate the performance of a geothermal based transcritical Rankine cycle for various supercritical working fluids. The geothermal reservoir is located in the west part of Turkey, and the geothermal water temperature is about 156 °C. Using the actual data, comparative thermodynamic analyses are carried out for determining the best working fluid. Results show that the highest power generation rate is calculated for the cycle using R170 with 6125 kW, followed by R744. In addition, the highest irreversibility is calculated for R125 with an exergy destruction rate of 8397 kW.

Keywords

• Geothermal energy,Transcritical Rankine cycle,Supercritical fluid,Exergy

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