Equivalent electrical circuit of thermoelectric generators under constant heat flow

Over the past decade, due to the rising demand of energy and increasing awareness of its efficient use, many research works have adopted the energy harvesting technologies as an alternative to the standard energy generation patterns. Due to its free availability and abundance, energy harvesting from heat by using Thermoelectric Generators (TEGs) is one of the most viable renewable sources of electricity. Thermoelectric generators can be used under constant temperature gradient or constant heat flow conditions. In this paper, a thermoelectric generator under constant heat flow conditions has been analyzed and modeled electrically. Moreover, an equivalent electrical circuit describing faithfully the TEG's behaviour under constant heat conditions has been presented. The circuit is simulated and validated with a SPICE environment and compared with the exact analytical model. The observed error is below 1%. The proposed model provides useful information about the influence of different TEG's parameters on the conversion efficiency, facilitating the properly design of thermal energy harvester.