Decision working medium for lower cycle CCGT trinary type

Abstract

The object of the study are low-boiling substances, which can be used as working fluid in the Organic Rankine cycle (ORC) combine cycle gas turbine (CCGT) trinary type. Purpose of research is search for substances with the best thermodynamic, thermophysical and ecological properties. The calculation algorithm represents a mathematical calculation of CCGT in which the lower cycle, operating on low-boiling fluid and utilizes low-potential heat, as an air-cooling device On the basis of available scientific and practical facts on the use of working fluids the organic Rankine cycle for analysis were selected ozone-safe refrigerant: butane, pentane, R236ea, R236fa, R123, R245ca, R245fа, R365mfc, RC318. For these substances were found and tabulated critical pressure and temperature, condensation pressure, density and dynamic viscosity at a given condensation temperature. Studies have shown that the highest thermal net efficiency is achieved when using natural Freon pentane and synthetic R365mfc. Net efficiency CCGT strongly depends on the condensation temperature of the substance. For example, when using pentane when the condensation temperature decreases on 10 °С net efficiency increases about 0.71 %.