Huge solar energy could soon be harnessed in the dark of night after significant advances in heat capture technology.
Solar radiation significantly warms the earth’s crust during the day, but that energy is lost in the cold of space when the sun sets.
Now researchers at the School of Photovoltaic and Renewable Energy Engineering at UNSW Sydney have successfully tested a device capable of converting infrared heat into electricity.
The team, including members of the ARC Center of Excellence in Exciton Science, used an energy-producing device called a ‘thermo-radiative diode’, which is similar to the technology in night-vision goggles.
Exciton research associate, researcher Nicholas Ekins-Daukes, leader of the research team, said: “In the late 18th and early 19th centuries it was discovered that the efficiency of steam engines depended on the temperature difference in the engine and area of thermodynamics was born.
“The same principles apply to solar energy – the sun is a source of heat, and a relatively cold solar panel on the Earth’s surface provides a cold absorber. This allows electricity to be produced.
“However, when we think about the infrared emission of the Earth into space, now the Earth is a relatively warm body, and the huge void of space is extremely cold.
“According to the same principles of thermodynamics, it is possible to generate electricity from this temperature difference: the emission of infrared light into space.”
Norwegian researcher Rune Strandberg was the first to investigate the theoretical possibility of such a device, and researchers from Stanford University are exploring alternative approaches to capturing heat energy at night.
The amount of energy produced by this new test is small (roughly equivalent to 0.001% of the solar cell), but the proof of concept is significant.
“We usually think of light emission as something that consumes energy, but in the mid-infrared region, where we all shine with radiant energy, we have shown that it is possible to extract electricity,” Nicholas said.
“We don’t yet have the miraculous material that will make a thermoradiative diode an everyday reality, but we have made a proof of principle and we are eager to see how much we can improve this result in the coming years.”
The team is now excited to move on to the next phase of research in creating and refining their own devices to harness the power of the night and welcome potential industrial partners.
The materials are provided by the ARC Center of Excellence in Exciton Science. Note: Content can be edited for style and length.