2002 年 78 巻 1 号 p. 19-35
Thermoelectric system has various merits for use in energy conversion because the temperature difference is only required to generate electric power and there are not movable parts in the system. However, thermoelectric system is not so popular in civil use because its energy conversion efficiency is not high in the present time. But if we consider the exergy flow even in a conventional turbine generator, the turbine generator system can not use energy completely, and a symbiotic and/or hybrid system can be applied, which is introduced in the present study. On the other hand, in fusion reactor there are many parts having large temperature difference because plasma temperature is high and superconducting magnets are used. One of the applications for superconducting system is mentioned and is called Peltier current lead. This can reduce heat leak to low-temperature system, and improve the efficiency of the whole system. Recently, material study has progressed, and various kinds of materials are proposed and studied. The magnetic field effect is introduced as investigated by the author's research group. Magnetic field effect was divided into three levels of the categories. One is in the macroscopic level, and this is characterized by the generalized Ohm's equation. The second level is characterized by Boltzmann equation, and in this level we can discuss the macroscopic transport parameters. The third level is the microscopic level and we discuss the band structure to solve the carriers themselves, for example Schrödinger equation. In this paper, our recent activities are mentioned in these fields.