Waste Heat Recovery Using Thermoelectric Oxide Materials

Oxide thermoelectric materials are considered to be promising ones because of their durability against high temperature, cost, no content of toxic elements, and so on. We have produced many types of modules using p-type Ca(3)Co(4)O(9) (Co-349) and n-type CaMnO(3) (Mn-113). The Co-349/Mn-113 modules show 4.2 kW/m(2) of power density against heated surface area. In order to enhance power generation and conversion efficiency, cascaded modules consisting of oxide and Bi(2)Te(3) modules. Thermoelectric units have been produced by stacking a heat collection fin, oxide and Bi(2)Te(3) based thermoelectric modules, and water jacket for cooling. Each unit includes 4 pieces of oxide/Bi(2)Te(3) cascaded modules. The surface area of the unit is 140 mm x 140 mm. Thermoelectric power generation test was carried out using a kerosene burner. Temperature around the heat collection fin and at the hot side of the oxide module reached about 1373 K and 943 K, respectively. Out put power from one unit is 49 W.