Theory and simulation of a thermally matched micromachined thermopile in a wearable energy harvester

In this paper, a new theoretical concept in the thermoelectric theory is discussed, which is important for design optimization of a thermoelectric energy harvester. The general conditions are defined, which are required to make a thermoelectric converter effective in energy harvester application. The necessity of the work has been prompted by the fact that while modeling the harvesters neither a constant temperature difference nor a constant heat flow can be assumed. It is shown that the proposed equations allow thermal optimization of energy harvesters to reach their top performance characteristics. The example of thermal optimization in case of MEMS thermopiles is discussed then. It is shown that the knowledge of thermal properties of the environment, i.e., those of a heat source and a heat sink, play the key role in the optimization procedure.