抄録
The heat even at relatively low temperature, such as hot spring, solar energy, waste heat from industry, are regarded as an important heat source of a power generation. When the Organic Rankine Cycle (ORC) is used, the great efforts are paid in order to reduce the irreversible loss at the heat exchangers, in addition to the improvement of the efficiency of expanders and liquid pump. In this study, the improvement of the ORC is investigated theoretically. In order to reduce the restrictions on the heat exchange conditions caused by pinch point that appears at the bubbling point in a normal ORC cycle, the use of a heat pump is proposed. R245fa is supposed as the working fluid of the ORC and also as the working fluid of heat pump. As a heat source hot water at 98℃ is supposed, and as the heat sink 30℃ water is supposed to be supplied. By the small temperature difference between heat source and heat sink, the work of the heat pump is kept at small level. The application of heat pump brings 3 to 28% output increase per unit hot water.
