Investigation into the use of thermoelectric modules as an alternative to conventional fluxmeters: Application to convective and radiative heat flux in buildings

Abstract

The aim of the present work is to propose a methodology for the use of thermoelectric modules (TEM) as an alternative to conventional heat flux sensors, for estimating convective and radiative heat flux. In this experimental study, the performance of TEMs as heat flux sensors is compared to that of the heat flux sensor (HFS), a type of conventional heat flux sensor, based on the premise that the HFS has been proven to perform acceptably in heat flux measurement. The interest of this comparison arises from the cost and sensitivity of the TEM with respect to the HFS. A simple measurement device is proposed, consisting of heat flux and temperature sensors with a general formulation for decoupling the convective and radiative parts. This methodology is implemented in two cases (low and high thermal stress). The radiative part is found to be the same by using the TEM and the HFS in both cases. However, the convective part measured by the TEM is found to be about 2.5 times larger than the HFS measurements in case of low thermal stress, and 1.6 times larger for tin case of high thermal stress. To explain this difference, the extended surface approximation was employed. This approximation indicates that the convective heat flux estimated from the TEM is always expected to be 1.6 and 1.4 times larger than that from the HFS for the low and high thermal stresses respectively, when their thermoelectric properties and geometry are taken into account.