Automatic biomass boiler with an external thermoelectric generator

Abstract. This paper presents the design and test results of an external thermoelectric generator that utilizes the waste heat from a small-scale domestic biomass boiler with nominal rated heat output of 25 kW. The low-temperature Bi2Te3 generator based on thermoelectric modules has the potential to recover waste heat from gas combustion products as effective energy. The small-scale generator is constructed from independent segments. Measurements have shown that up to 11 W of electricity can be generated by one segment. Higher output power can be achieved by linking thermoelectric segments. The maximum output power is given by the dew point of the flue gas. The electrical energy that is generated can be used, e.g., for power supply or for charging batteries. In the near future, thermoelectric generators could completely eliminate the dependence an automated domestic boiler system on the power supply from the electricity grid, and could ensure comfortable operation in the event of an unexpected power grid failure