engineers at the university of nebraska – lincoln have created a nano-thermal-mechanical device, a thermal diode, which provides an alternative energy source for computing at temperatures exceeding 600°f, according to a report on the school website.  

sidy ndao and mahmoud elzouka developed this thermal diode that may allow
computers to use heat as an alternate energy source. (karl vogel/engineering)

the concept goes against the standard thinking with computers, which is avoiding heat in order to ensure performance. the engineers, sidy ndao and mahmoud elzouka, believe that they have created the building blocks for a thermal computer and expect that it will work in heat as extreme as 1,300°f.

this could be a breakthrough for space exploration, oil drilling, underground explorations, and help control energy consumption during the computing process by limiting the amount of energy that is wasted. thermal battery technology could benefit from this research.

the researchers have filed for a patent, but insist there is still work to be done to improve the diode and to build a working thermal computer.

an article on phys.org explained, “the function of a thermal diode is to allow heat to flow primarily in one direction but not the other, similar to how an electronic diode allows electric current to flow primarily in one direction. this ability to control the direction of flow enables diodes to produce two distinct levels of a signal, forming the basis for the ‘0’ and ‘1’ binary logic levels.

the new thermal diode achieves two distinct levels of heat flow by controlling the distance between two surfaces: a moving terminal and a stationary terminal. the researchers showed that changing the relative temperatures of the two terminals changes the gap size between them, which changes the amount of heat transfer, which in turn depends on the direction of heat flow.”

the article added that the device is composed of 24 pairs of moving and fixed terminals on two thin-film platinum microheaters, which control and measure temperatures at the terminals.

it continued, “when the fixed terminal is hotter than the moving terminal, the gap is large, resulting in a low heat transfer rate. when the moving terminal becomes hotter than the fixed terminal, the moving terminal moves closer to the fixed terminal and the gap decreases, leading to a higher heat transfer rate.”

the research was recently published in scientific reports. the abstract stated:

“limited performance and reliability of electronic devices at extreme temperatures, intensive electromagnetic fields, and radiation found in space exploration missions (i.e., venus & jupiter planetary exploration, and heliophysics missions) and earth-based applications requires the development of alternative computing technologies.

“in the pursuit of alternative technologies, research efforts have looked into developing thermal memory and logic devices that use heat instead of electricity to perform computations. however, most of the proposed technologies operate at room or cryogenic temperatures, due to their dependence on material’s temperature-dependent properties. here in this research, we show experimentally—for the first time—the use of near-field thermal radiation (nftr) to achieve thermal rectification at high temperatures, which can be used to build high-temperature thermal diodes for performing logic operations in harsh environments.

“we achieved rectification through the coupling between nftr and the size of a micro/nano gap separating two terminals, engineered to be a function of heat flow direction. we fabricated and tested a proof-of-concept nanothermomechanical device that has shown a maximum rectification of 10.9% at terminals’ temperatures of 375 and 530 k.

“experimentally, we operated the microdevice in temperatures as high as about 600 k, demonstrating this technology’s suitability to operate at high temperatures.”