This paper discusses a hot spring power generation system using the thermal energy obtained from the temperature difference between the hot water drawn up and the hot water supply to the hot spring facilities. In order to clarify the feature of a hot spring power generation system using ammonia (NH_3) as the working fluid, the thermal efficiency, required hot water flow rate, and sizes of heat exchangers and turbine rotor are calculated compared with the conventional system using chlorofluorocarbon (R134a, R123, R22 ) as the working fluid. As the results, it shows the effectiveness of a hot spring power generation system using NH_3.
