A new system, based on graphene, can draw power from daily temperature swings. The technology can harness temperature fluctuations of many kinds in order to produce electricity.
The new thermoelectric device comes from the Massachusetts Institute of Technology (MIT) and it draws power from the daily cycle of temperature swings. The concept is generating power when one side of the device is at a different temperature from the other side. This process produces sufficient to power remote sensors and several types of communications systems.
In the trials the device, reacting to a 10-degree-Celsius temperature difference (between night and day), generated 350 millivolts of potential and 1.3 milliwatts of power.
The material selected was a metal foam formed of copper. This was then coated with a layer of graphene to enhance the thermal conductivity. The foam was next infused with octadecane, which is a phase-change material that resembles a wax. Octadecane can change between solid and liquid at a particular range of temperatures. Through the material heat is collected from one side and it gradually radiates through to the other.
The research has been reported to the journal Nature Communications, and the research paper is titled “Ultra-high thermal effusivity materials for resonant ambient thermal energy harvesting.”
In related energy news, the U.S. regulators have permitted large-scale energy storage using batteries for the first time, disrupting the monopoly held by state power grids. See the Digital Journal article “Market barriers removed for energy storage technology.”