While the idea of generating solar power after the sun has set may seem impractical, researchers at the University of New South Wales have found a way to accomplish it. They have developed a new technology that could soon be powering our homes at night.
Notably, the researchers have already tested this device on the Earth, and now they are planning to assess its usability in space as well.
Their technology works on the principle of thermoradiative power generation. This process capitalizes on the temperature difference between the Earth’s surface and the coldness of space. For reference, all objects, including the Earth, emit infrared radiation.
Capturing and converting radiant heat
The newly developed device captures this outgoing radiation and converts it into electricity. The key component of this device is a semiconductor, which has been specifically designed to take advantage of this radiant heat.
As the Earth emits infrared light, the semiconductor captures this energy and generates an electrical current. By capturing and converting this radiant heat into electricity, the device essentially generates “solar power during the night-time.”
“What we did was we made a semiconductor device … it takes advantage of that radiant heat that’s leaving the Earth, and as that light is emitted, it generates some electricity,” team lead Ned Ekins-Daukes told ABC News.
Inspiration from night-vision
According to a press release issued by the researchers, the semiconductor device was a type of thermoradiative diode. Interestingly, the materials that were used to create this device were similar to those found in night-vision goggles.
“In the same way that a solar cell can generate electricity by absorbing sunlight emitted from a very hot sun, the thermoradiative diode generates electricity by emitting infrared light into a colder environment,” explains Dr Phoebe Pearce, one of the researchers on the project.
“In both cases the temperature difference is what lets us generate electricity.”
The efficiency of this new technology is currently low, but the research team is optimistic about future improvements.
The amount of power was small, 100,000 times less than that supplied by a solar panel, but it was an ‘unambiguous demonstration of electrical power,’ said Professor Ekins-Daukes in the press release.
From wearables to satellites – Potential applications
The research team anticipates that this new technology will have a wide range of applications, going beyond the limitations of current energy sources. Professor Ekins-Daukes even suggests the possibility of harnessing body heat to generate power.
“Down the line, this technology could potentially harvest that energy and remove the need for batteries in certain devices – or help to recharge them. That isn’t something where conventional solar power would necessarily be a viable option,” he remarked.
On a larger scale, the team is actively working on adapting the technology for use in spacecraft. Satellites in low Earth orbit experience frequent eclipses, relying on batteries during periods of darkness. The thermoradiative diode offers a potential solution, generating power even in the absence of sunlight.
“We now generate very large quantities of electricity from solar power for our homes using silicon solar cells, that technology which was first used in space. In a similar way, we intend to fly the thermoradiative diode in space within the next 2 years,” concluded Prof. Ekins-Daukes.
This breakthrough could pave the way for a future where renewable energy is available 24/7. It has the potential to lead to a world where homes are powered even when the sun is down, using nothing but the Earth’s own radiant heat.
