Waste heat recovery (WHR) based on thermoelectric generators (TEG) could improve energy efficiency and reduce carbon emissions. TEG could directly convert low-grade heat into electric energy. There have been many reports on laboratory experiments on evaluating the performance of TEG by measuring the power output at different conditions. However, there have been few field tests using waste heat with a temperature of less than 100 °C with TEG devices, which is of great significance because there is huge waste heat within this temperature range. TEGs were usually and mostly used for low-power microelectronic devices. In these cases, only one or several instead of hundreds of TEG modules were utilized. In this study, we conducted the field tests of TEG using the waste heat with a temperature of 80 °C at a gas power plant located in Shanxi province, China. We tested two TEG devices with 10 (240 TEG modules) and 20 layers (360 TEG modules), respectively. To our best knowledge, the number (20) of layers in one TEG device is the biggest so far reported in the literature. The field test results were analyzed and compared with laboratory experiments and other field tests at a high temperature of 170 °C. The power output and efficiency of TEG were measured and calculated at different temperature differences and flow rates. The TEG device could provide a power of 167.8 W for a flow rate of 3 cubic meter per hour at a temperature difference of 60 °C (the temperature of the heat resource was 80 °C). The cost of TEG device used in the field tests was estimated and compared with other power generation technologies. The field test results in this study demonstrate the feasibility of using TEG for recovering large scale waste heat.
Keywords thermoelectric generators (TEG), field test, green power, waste heat recovery