Energy literally surrounds us from all sides. The whole question is how to get it. A team at the Massachusetts Institute of Technology (MIT) has developed a device - a thermal resonator, with which you can extract electricity from the surrounding air using daily temperature drops.
Experiments with temperature fluctuations as a source of energy have been carried out for a long time. Most of the devices designed to do this generate electricity by exploiting the differences in temperature between the two sides of a material. As you know, heat moves from the warmer side to the colder one, "dragging" the charges along with it, resulting in a voltage difference - that is, an electric current.
Thermoelectric experiments have already been carried out with clothing, paints and cooking pots, which can be integrated into the power grid of enterprises to recirculate waste heat. However, in order to get the desired output, the temperature differences must be quite significant.
The thermal resonator is filled with a heat-trapping material - a foam composed of copper, nickel and a phase-forming wax - octadecane, which shrinks and hardens at certain temperatures. The foamy mixture is covered with a layer of an excellent heat carrier - graphene.
Taken together, this combination of materials gives the device a very high effusion (the slow flow of molecules through tiny holes without colliding with each other). This means that the material efficiently generates heat to the adjacent environment.
Basically, heat is trapped on one side of the device and slowly radiated through the material to the other. Since one side of the material is always colder than the other, heat will constantly circulate, trying to establish balance. At this point, energy can be harvested using conventional thermoelectric systems.