Split flow principle implementation for advanced subcritical double stage organic rankine cycle configuration for geothermal power production

The main goal of research is to find the most suitable combination of working fluids, for double stage Organic Rankine Cycle configurations which ensure maximum net power output for low to medium enthalpy geothermal sources with temperatures from 120 degrees C to 180 degrees C. All obtained results are compared with the values obtained in simple Organic Rankine Cycle configuration. In general, it can be concluded that the highest net power output is produced by the double stage Organic Rankine Cycle configuration in the geothermal temperature interval from 120 degrees C to 132 degrees C. In the geothermal fluid inlet temperature interval from 143 degrees C to 180 degrees C double stage Organic Rankine Cycle configuration achieves the highest net power output values at 150 degrees C, 160 degrees C, 170 degrees C and 180 degrees C and that 40,93 (kW) with a combination of working fluids R236fa/R1234yf (high temperature stage/low temperature stage), 49,85 (kW) with R236ea/R227ea, 59,03 (kW) with R236ea/R227ea and 69,40 (kW) with nButane/R1234ze(E). In the temperature interval from 132 degrees C to 142 degrees C all considered configurations achieve similar values of net power output.