| Abstract: | The present thermoelectric semiconductor integrated into the commercially available thermoelectric units are not designed elaborately for low temperature difference operation. Those elements available in the room-temperature range are usually applicable for the temperature difference around 60 K with relatively poor coefficient of performance. For air-conditioning purposes, it is expected that the thermoelectric energy conversion will have a high coefficient of performance as well as economical advantage because of the low temperature difference operation. This paper describes basic and analytical considerations for low temperature-difference operation, and also the new design systems desired from viewpoints of the effective and economical use of environmental energy. An appropriate design allows a drastic economy in the material and also a drastic improvement in the coefficient of performance, and it is possible to put the material, with the presently available figure of merit, in practical use. The availability of a simple cascade connection is discussed for the operation under some increased temperature difference. The concept of the cooling or heating systems using thermoelectric units driven by a solar-cell array will also be proposed and experimental results will be illustrated. |
