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Session: Poster session & Sponsor Exhibition
Session starts: Monday 07 October, 14:00

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Eunkoo Yun ()
Hyun Dong Kim (Pusan National University)
Sang Youl Yoon (Pusan National University)
Kyung Chun Kim (Pusan National University)

Abstract:
Organic Rankine cycle (ORC) system has good potential for heat recovery from low-temperature heat sources. But, in some applications including industrial facilities, marine engines, solar thermal heat, and other sources, the heat fluctuation from heat source is very large. Due to the large heat fluctuation, the efficiency of single-expander system could be severely reduced, and the system might be non-operational. In order to overcome the limitation, this study proposes an ORC system with multi-expander in parallel which can actively respond to the large heat fluctuation. This study aims to evaluate the performance of an organic Rankine cycle (ORC) power system adopting multi-expanders in parallel by simulation and experiment. The ORC system consists of two scroll expanders installed in parallel, a hydraulic diaphragm type pump to feed and pressurize the working fluid, two plate heat exchangers for the evaporator and the condenser. The two scroll expanders were modified from two oil-free air scroll compressors (Kyungwon Co., Ltd., Korea) with same specifications, and were tested in the ORC loop with R245fa. The hot water was used as heat source and the temperature was controlled up to 150 °C by the 150 kW-class electric heater. In order to determine the static performance of the system, efficiencies and shaft powers for both single and dual operation modes were measured under various heat source temperature conditions ranged from 110 °C to 140 °C. The maximum isentropic efficiency of each expander was measured about 70%, and the shaft power was reached to about 3 kW at the turbine inlet temperature of 140 °C. In addition, dynamic performance tests were conducted with oscillating heat flux conditions. The characteristics and overall efficiencies of the dual parallel expander ORC system with regards to various heat source conditions and operation modes will be addressed.