Comparative analysis of selected thermoelectric generators operating with wood-fired stove

Abstract Nowadays, the use of wood for cooking and heating has become very popular, especially in rural and suburban areas. Fireplaces and solid fuel stoves with heat accumulation provide both low-cost heating and an aesthetic atmosphere from burning wood. Additional benefits may also be connected with micro-scale power generation, realized using thermoelectric generators. The aim of this study was to examine the selected aspects of integration of a typical wood-fired stove with commercially available thermoelectric generators. Among several aspects included in the carried out analysis, there were e.g. the operation parameters of the tested stove (including temperature variations during combustion process), the efficiency of electricity generation in the tested thermoelectric generators and the requirements for the stove configuration and operation. Three types of thermoelectric generators were tested: two generators designed for mounting on a flat hot surface (cooling respectively by air and water) and one designed for mounting on a flue gas channel (cooling by water). The experiments were carried out using dedicated measuring, controlling, and visualizing systems with a PLC controller as well as an infrared camera. Thermographic analysis allowed determining of the temperature distribution on the rear wall of the stove and selection of the most optimal areas for mounting generators. However, non-homogeneous temperature distribution was observed, identified as one reason for lowering of operational efficiency of the generators. A further problem was identified in the case of the generator mounted on the flue gas channel being too low a cross-section of its gas channels (reducing flue gas flow volume). These problems significantly impacted on the operating characteristics of the thermoelectric generators – meaning they produced no more than 41.7, 31.2, and 7.2% of their nominal power, respectively. The obtained results enabled the proposal of two approaches connected with further development of the micro scale cogeneration systems with thermoelectric generators: These two methods would differ in terms of costs, final product price, and necessary fitting of production lines.