A research group at the Massachusetts Institute of Technology has developed a device called a thermal resonator that can produce electricity using a gradual change in ambient temperature throughout the day. Scientists have been experimenting for many years to use temperature fluctuations as an energy source. Most of these devices work on the thermoelectric principle, which means that they use the temperature difference across the material to generate electricity. As heat flows from the hotter side to the cooler side, charge carriers flow with it and create a voltage difference. , thereby generating electricity in the process.
However, in all of these applications, the temperature difference needs to be considerable. Now, the new technology gradually fluctuates more gradually over a longer period of time, enabling it to work with natural changes in temperature throughout the day. This is Called the thermoelectric effect. Michael Stella, one of the authors of the study, said: 'We basically invented this idea with a whole piece of cloth. 'We made the first thermal resonator that can be placed in On the table, energy is generated from where there is nothing. We have been surrounded by temperature fluctuations of all different frequencies. These are untapped energy sources.
The active part of the thermal resonator is a foam made of copper or nickel that is injected with a phase change wax (called octadecane) that liquefies and cures at certain temperatures. The foam mixture is coated on a layer. In graphene, this is an excellent thermal conductor. In summary, the specific combination of this material allows the device to have a very high thermal expansion, which means that it can effectively absorb and release heat into the surrounding environment.
Basically, heat is trapped on one side of the device and slowly radiates through the material to the other side and is stored in the middle phase change material. Since one side of the material is always colder than the other side, the heat will try to build It moves back and forth during the balance. It can then be collected using a conventional thermoelectric system. The researchers tested a sample of this material in 16 days. During that time, the daily temperature fluctuations were as high as 10°C (18°F). The system can be powered up to generate 350 millivolts and 1.3 milliwatts of power. Its performance exceeds the same specification for pyroelectric materials.
The researchers said that the system is capable of running low-power, remote sensors and devices without worrying about batteries. Moreover, because it uses ambient temperature fluctuations, it is not bound by solar or wind energy.
