Output Power Characteristics of Reciprocating Heat Engine Using Shape Memory Alloy

In order to develop the utilization technology in which unexploited energy is retrieved and transformed into power, we have proposed a heat engine incorporating shape memory alloy wires. In this work, the output power characteristics are investigated experimentally from the viewpoints of maximization of the output power, stabilization of the power during operation and the amount of work to failure. Experiments are conducted at various heating and cooling temperatures, volocities of heating and cooling water and wire diameters. As a result, it is clarified that the output power increases with increases in both the heating temperature and the velocity of heating water. The output power also increases with decreasing cooling temperature. However, the velocity of cooling water at which the output power is maximum varies with the cooling temperature. Furthermore, the amount of work to failure does not always increase with increasing fatigue life and becomes maximum under the operating conditions at which the output power becomes maximum.