Called a thermal resonator, the device relies on temperature fluctuations between day and night to produce electricity and can be used without the need for sunlight, batteries or wind
Researchers at MITâ€™s Department of Chemical Engineering recently developed a device that could continuously produce electricity by taking advantage of the swings in ambient temperature that occur during the day-night cycle, without requiring other power sources or batteries. The findings of their work are being reported in the journal Nature Communications.
According to the scientists, the new device -called a thermal resonator- could keep remote sensors or any off-grid device powered up for years, just by using temperature swings â€“ like the natural ones between night and day, for instance. Although they have been experimenting with ways to use temperature fluctuations as a source of energy for years now, taking advantage of temperature differences between two sides of a material, the new technique taps into more gradual fluctuations over longer periods of time, while working with the natural changes in temperature throughout the day. â€œWe basically invented this concept out of whole cloth,â€ says Michael Strano, Professor of Chemical Engineering and co-author of the study. â€œWeâ€™ve built the first thermal resonator. Itâ€™s something that can sit on a desk and generate energy out of what seems like nothing. We are surrounded by temperature fluctuations of all different frequencies all of the time. These are an untapped source of energy.â€
The heat is captured on one side of the device and slowly radiates through the material to the other, while energy resulting from the process is stored in the phase-changing material in the middle. Since one side of the material will always be cooler than the other, the heat will constantly be moving back and forth as it tries to establish equilibrium. This energy can then be harvested using regular thermoelectric systems. â€˜The thermal resonator was shown to outperform an identically sized, commercial pyroelectric material â€” an established method for converting temperature fluctuations to electricity â€” by factor of more than three in terms of power per areaâ€™, says graduate student Anton Cottrill, the studyâ€™s lead author. The deviceâ€™s output is still relatively modest, but its advantage is that it generates energy from ambient temperature changes even in the shade, remaining unaffected by short-term changes in cloud cover, wind or other environmental conditions. This means that it can be located anywhere, even in perpetual shadow or underneath a solar panel, while at the same time allowing it to be more efficient by drawing away waste heat, according to the researchers.
Source: MIT News