Thermoelectric generators - Design, performance and application

In the present state of the art the construction of useful thermoelectric generators requires careful planning on the part of the design engineer. He must be aware of the significant factors that influence the performance, reliability, life, and ease of fabrication of the generators. This paper illustrates many of the practical problems that are encountered in building present clay generators. A design procedure for free convection air-cooled generators is described. The performance of power thermocouples as a function of junction temperature is discussed and curves illustrating couple efficiency, power output, heat flux, and voltage as a function of hot junction temperature are illustrated. The effects of varying thermocouple length on generator efficiency and generator specific power are shown graphically and methods of predicting generator performance as the number of thermocouple is varied are illustrated. The paper also discusses free convection heat exchangers and fossil fuel burners. In addition, the thermoelectric generator performance on a watts per pound basis is compared with battery and gasoline engine driven generator performance for specific missions.