Estimation of power generation in a thermal oil heater by a new material based thermoelectric generator

During the last three decades, there has been growing interest in applying thermoelectric technology to improve the efficiency of waste heat recovery. This study reports an estimation of the amount of power produced by a thermoelectric generator (TEG) placed between the flue gas duct and fresh air duct of an industrial thermal oil heater to recover waste heat. A plate fin heat sink is used to transfer the heat from flue gas to the thermoelectric generator. The effects of various design parameters and flow parameters were investigated in order to maximize the power generation. Then the best suited conditions were applied to new a thermoelectric generator module based on recently developed Bi₂Te₃, PbTe and TAGS thermoelectric group materials. A thermoelectric generator based on p-type (Bi,Sb)₂Te₃ and n-type hot forged Bi₂Te₃ generates 4.4 W, which is about 19% improvement in output power compared to a commercial module (HZ-2). For a proposed system, in a biomass fired thermal oil heater, the estimated annual power generation could be around 181,209 kWh. The thermal efficiency of the TEG modules based on recently developed thermoelectric materials could be enhanced by up to 8.18%. The specifications of plate fin heat sinks as well as thermoelectric properties of the p-n materials of the system have a substantial impact on the performance of the TEG module.