Researchers are looking for ways to generate power from different sources and this includes heat energy too. In a recent presentation UNSW team’s dark solar device can power US space stations.
A team of researchers from UNSW Sydney displayed the possibility of creating light-based electricity in the dark. This demonstration took place a few years ago and in 2024 they are nominated for the Eureka prize. It is Australia’s most prestigious science award. Moreover, they also have secured funding from the US Airforce for developing their technology to use in outer space.
Professor Ned Elkin-Daukes, leader of a team at the University of New South Wales (UNSW) said, “What these devices do is the opposite of a solar panel. In this case, we call it a thermoradiative diode. This device is warm and it generates power when it emits light into cold surroundings.”
Heat to Light
The thermoradiative diode uses the light produced by the heat energy. The warmer parts of the building emit light. Instead of measuring the light waves from heat, the diode turns it into electricity of much lower energy density.
Unlike solar panels, the concept of efficiency is not applicable to this technology. This is because the energy source is variable. This means the diode could have higher efficiency, somewhere 50% more than PV panels but generate little power. It is also possible for it to have single-digit efficiency but generate higher power.
Suppose a PV panel generates 220 watts per square meter, the 2022 version of thermoradiative diode in the lab reaches 2 milliwatts per square meter. Presently, the team aims to increase this output to tens of watts per square meter.
The 1st Demonstration
In 2019, the project showed that the concept works on thermodynamic theory. According to it, any type of light generated by heat should be able to generate electricity. Even if its wavelength is too low to be visible to the human eye, it is possible to work.
The 2nd Approach
Then in 2021, they developed a prototype with materials found in night-vision goggles. This was a lab-bench-top model operated at room temperature. But even at that stage, their approach was unable to secure any funding.
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The 3rd Try
This time the team is building a thermoradiative semiconductor alloy III-V instead of mercury cadmium telluride. It is more adaptable than the night-vision ones. They are also testing it under temperatures experienced in space.
The approach is to add technology to satellites in low Earth orbits that usually have 45-minute day and 45-minute night.
With advancements in microelectronics, researchers are hopeful that it won’t take long to transition from rooftops to sky.
Source: Dark solar UNSW team win US funding for night-light electricity
