THERMODYNAMIC ANALYSIS OF THE ORGANIC RANKINE CYCLE AND THE EFFECT OF REFRIGERANT SELECTION ON CYCLE PERFORMANCE

TheOrganic Rankine cycle is a power-generation system for lower temperature rangesin which organic fluids with hydrocarbon components are used instead of water.Organic Rankine Cycles, which are suitable for heat recovery applications atlow temperatures, can be used for generating electric energy from various wasteheat sources. In this study, a thermodynamic analysis is conducted on anexample Organic Rankine Cycle that is used to generate electric energy from a geothermalsource. The working fluid to be used in the cycle was selected as R134a,R236fa, R245fa and R600a, which are commonly used. For these selected organicfluids, the required cycle performance to generate 1 MW of energy from theturbine was analyzed according to the geothermal source temperature (90-140°C),and the thermal efficiency of the cycle was calculated. The obtained resultsare presented comparatively with the help of the graphs. R245fa was defined tobe more appropriate for the cycle as a refrigerant at constant work conditions.