Feasibility Study on a Small Power Rankin Cycle Driven by a Low Temperature Difference

We aimed to develop a small power Rankine cycle for suppling an auxiliary power by the hot spring water, which provides a small temperature difference from the ambient temperature. According to the results of the performance test of an actual scroll turbine, the mechanical efficiency of the turbine was approximately 30%. In the comparison among the three kinds of organic refrigerants, the cycle driven by R245fa indicated the lowest power consumption in the feed pump and the highest thermal efficiency. Our analysis indicated that the net output of the cycle was lower than that of the designed output, because the pressure did not reduce to the theoretical value due to the inherent pressure ratio of the volume type turbine