EXPERIMENTAL STUDY ON ORGANIC RANKINE CYCLE ADOPTING DUAL-EXPANDERS WITH DIFFERENT CAPACITIES IN PARALLEL

asme-orc2015 Tracking Number 146

This study aims to experimentally investigate the possibility of an organic Rankine cycle (ORC) adopting dual-expanders with different capacities in parallel. The proposed ORC system was designed to provide competitive advantages over basic ORC system having single expander in case of applications with large waste heat variation. The system could have three operating modes according to the operated expanders; Single mode1, Single mode2, and Dual mode. In Single mode, only one expander (expander1 or expander2) is operated, and in Dual mode both expanders work. Hence, each operating mode has each different heat recovery capacities, and each operating mode has its own design point which can achieve the maximum performance. Therefore, the three heat recovery capacities and the three design points in single ORC system allow more effective heat recovery in applications with large waste heat variations. Two scroll expanders, which have 1 kW and 5 kW class capacities, were utilized in an ORC loop for the experimental test. The ORC test bench consisted of a 100kW heater as the heat source, an ORC loop, and an air-cooled chiller as the heat sink. R245fa was used as working fluid. In order to evaluate the performance characteristics of the system, efficiencies and shaft powers for each operating mode were measured under various evaporative heat transfer conditions. The appropriateness of utilizing proposed ORC system and optimal operation mode which can produce higher power output will be discussed with experimental results.