Experimental study of operating load variation for organic Rankine cycle system based on radial inflow turbine

Based on the self-developed high-speed radial inflow turbine and R245fa as the working fluid, organic Rankine cycle (ORC) testing rig of low-temperature waste heat power generation was built. The effects of different operating load power on the ORC system performance were studied through the experiment. The results show that the isentropic efficiency of the turbine, output power, electric power, thermal efficiency, and exergy efficiency of system, all reach the maximum values at the optimal load power of 1.7 kW, and at this condition, electric power, thermal efficiency and exergy efficiency of system are 1.424 kW, 2.52% and 8.09%, respectively. Therefore, when the ORC system is designed, the turbine, generator and load power should be matched to the optimal performance of the system. By grey relational analysis (GRA), it is concluded that electric power has the closest correlation with load power, with its grey relational grade being 0.632. Compared with the exergy efficiency, the thermal efficiency maintains a higher relational grade. In addition, according to exergy analysis, the evaporator is the component with the highest exergy loss, followed by the condenser.