Development of a thermoelectric power generation system using reciprocating flow combustion in a porous FeSi2 element

A thermoelectric power generation system using reciprocating flow combustio n in a porous thermoelectric conversion element has been developed and exam ined in its performance. Mn- (n-type) and Co- (p-type) doped FeSi2 powders were molded into the cylindrical element via a spark plasma sintering proce ss, in which Mn- and Co-doped parts were separated by a thin insulator shee t exclusive of a terminus. The porous element consisted of two semicylindri cal p/n couples, arranged electrically in series but thermally in parallel. A thermopower of 1.0-1.2 mV/K at 295-624 K and an apparent internal resist ivity of 1.6x10(-1) Omega cm at 556-624 K have been obtained for the elemen t. A power generation system was then made using a pair of the elements, wh ich were arranged lengthwise in a cylindrical combustion chamber. A recipro catory flow of dilute fuel gas was introduced into the element, and it was ignited between the element. A steep temperature gradient of about 200 K/cm was formed lengthwise in both elements. The energy density has reached as much as 7 kW/m(3) (excluding combustion chamber and mounting clamp) by the reciprocating flow combustion with a dilute fuel gas which may not even be normally flammable. (C) 2001 American Institute of Physics.