A way of achieving a low $/W and a decent power output from a thermoelectric device

While most research concerning thermoelectrics has focused on the enhancement of the thermoelectric figure of merit, zT, the $/W is a direct indication of its practical use. It is suggested that in the conventional device architecture, it is better to reduce thermoelectric material consumption rather than to increase zT for higher conversion efficiency, i.e., higher power output with given heat input for lower costs, in certain cases. As a result of this, a thermoelectric device with low $/W suffers from its low power output. Here, we present another way to lower the $/W value, while maintaining a decent power output of a thermoelectric device by changing the device architecture. In the analytical expression which we deduced, we demonstrated that the $/W value can be reduced to around 10% while maintaining ∼65–70% of the maximum possible power output with a given zT. The device architecture we propose should be useful to recover low quality waste heat, which is abundant and could be harvested as long as the $/W value is low enough in general.