Iron-based element for low temperature thermoelectric generator

Direct conversion of low temperature waste heat source into electrical energy with thermoelements is an interesting and challenging problem. In this study, the thermocouple consisting of a junction between Fe and Fe-7 similar to 12mass%Al alloy has been developed. The uni-couple exhibits the power of 40 mu at room temperature which is equivalent to that for the junction between Cu and Constantant. The iron and iron-aluminum alloy may be of great significance as materials for low temperature thermoelectric energy conversion because of their abundant production. Cold-roll formed steel sheets were used for trial manufacture of a generator with a series connection of thermoelectric elements. The steel sheet was bent in sharp waves, wrapped with aluminum foils tightly on the reciprocal planes of the waves and heat-treated for alloying by diffusion of aluminum into the steel matrix. Electric power generating facility using the iron and iron-based devices may have definite advantages It has no moving parts and requires very little attention. It cannot wear out. Therefore, the determining factor of the possible use of thermoelectric generator is its efficiency. So, the latter half of this paper has been focused on the possibility to convert low temperature heat source into useful power with high efficiency. Recovery of electricity was discussed on the basis of a thermoelectric generator of the heat exchanger type in which the heat transferred by conduction through a energy panel consisted of a series of thermoelectric elements is accumulated in the air circulating as coolant and recycled as a heat source for the use to a subsequent thermoelectric panel.