EXPERIMENTAL STUDIES ON AN ORGANIC RANKINE CYCLE (ORC) SYSTEM UNDER VARIABLE CONDENSATION TEMPERATURE

asme-orc2015 Tracking Number 64

For a thermal power system the operating condensation temperature fluctuates significantly throughout the year in many areas due to the change of ambient temperature. Therafore, off-design operation of an organic Rankine cycle (ORC) system is unavoidable. The present paper focuses on the test and analysis of an ORC system using R123 as the working fluid under various condensation temperature conditions. A scroll expander was integrated into the ORC system and connected with a synchronous generator. The exhaust gas from a furnance and the water from cooling tower were adopted to simulate the low-grade heat source and the cold source,respectively.The temperature of the exhaust gas was about 180°C.With the increasing of the cold water temperature from 22°C to 42°C,the condensation temperature of the working fluid varied from 50 °C to 65 °C and the pressure from 0.21MPa to 0.32MPa, respectively. It affected the expansion ratio and the temperature difference between the inlet and out of the expander, evaporator, condenser, pump and the whole system were influenced subsequently. The measured electric power output declined from 2.36kW to 1.54kW, and the thermal efficiency fell from 7.25% to 5.52% as well. Under the operation conditions, the electric power and thermal efficiency decreased, by34.75% and 23.86%, respectively.These results indicate that the operating condensation temperature plays a key role on the performance of the ORC system, and suggest that a proper condensation temperature is important to the design and operation of the ORC system.