Thermoelectric module construction for low temperature gradient power generation

Energy related carbon dioxide emissions are the largest contributors to greenhouse gasses [1]. Thermoelectric power generation that exploits natural temperature differences between the air and earth can be a zero-emission replacement to small stand-alone power sources. Maximizing the temperature drop across the module is crucial to achieving optimal output power. An equation relating output power to thermoelectric module parameters is derived. In addition, several configurations are investigated experimentally. Output power shows a significant dependence on module surface area. In the setups tested, one side of the thermoelectric module was thermally coupled to the earth, while the other side was left exposed to air. This paper evaluates three 110-hour experiments. The surface area of the exposed side was varied by a factor of about 15 without changing the area covered by thermoelectric elements. The output power shows a direct dependence on exposed surface area and changes by about a factor of 25.