Energy harvesting analysis of wearable thermoelectric generators integrated with human skin

Abstract

This paper proposes a novel configuration for wearable thermoelectric generators (W-TEGs) in which the fill material only encloses each thermoelectric leg with a specific size. An analytical model for the presented W-TEG integrated with human skin is developed. Numerical results show that the metabolic heat generation can be neglected, but the maximum power density of W-TEG will be underestimated by 30.72% if the influence of heat exchange induced by blood perfusion is not considered. The matched load resistance, the optimal fill factor and optimal length of thermoelectric legs corresponding to maximum power output of W-TEG are also obtained. The matched load resistance ratio and optimal fill factor of the W-TEG are 1.4090 and 10.01%, respectively, which are quite different from the values of classical thermoelectric generators (TEGs). The study further indicates that the performance of W-TEG can be improved by increasing the contact pressure at skin/W-TEG interface. Additionally, the impact of heat convection at lateral surfaces of thermoelectric legs should be taken into account to accurately estimate the power output of W-TEG. The optimization parameters presented in this paper may pave a way for achieving higher performance of W-TEG with actual applications.