Diagram of a differential temperature thermopile with two sets of thermocouple pairs connected in series. The two top thermocouple junctions are at temperature T1 while the two bottom thermocouple junctions are at temperature T2. The output voltage from the thermopile, ΔV, is directly proportional to the temperature differential, ΔT or T1 - T2, across the thermal resistance layer and number of thermocouple junction pairs. The thermopile voltage output is also directly proportional to the heat flux, q", through the thermal resistance layer.Picture of a heat flux sensor that utilizes a thermopile construction to directly measure heat flux. Model shown is the FluxTeq PHFS-01 heat flux sensor. Voltage output is passively induced from the thermopile proportional to the heat flux through the sensor or similarly the temperature difference across the thin-film substrate and number of thermocouple junction pairs. This voltage output from the sensor's thermopile is initially calibrated in order to relate it to heat flux.
A thermopile is an electronic device that converts thermal energy into electrical energy.[1] It is composed of several thermocouples connected usually in series or, less commonly, in parallel. Such a device works on the principle of the thermoelectric effect, i.e., generating a voltage when its dissimilar metals (thermocouples) are exposed to a temperature difference.[1]
