Swiss researchers have developed a device that uses solar energy to heat to more than 1,000 C. The technology could make it possible to use solar energy to decarbonize energy-intensive industries that require high temperatures for production processes.
A research team from the Swiss research institute ETH Zurich has developed a new thermal trap technology that can absorb concentrated sunlight and provide heat of more than 1,000 C.
The thermal trap system consists of a quartz rod with a diameter of 7.5 cm and a length of 30 cm, coupled with a ceramic absorber that, due to its optical properties, can absorb sunlight and convert it into heat.
The left end of the system’s rod is exposed to concentrated solar radiation and the right end is in contact with an opaque silicon carbide disk, which serves as a solar absorber. According to the research article, tThe use of opaque material is important because when exposed to solar radiation, the material absorbs the radiation at the surface and transmits it across the walls via conduction, which means that the highest temperature is reached on the absorbing surface.
Image: ETH Zurich/Emiliano Casati
In laboratory-scale experiments, the researchers exposed the rod to artificial light with an intensity 135 times that of sunlight, reaching temperatures of up to 1050 C. According to the university, previous studies by other researchers have reached a maximum of 170 C. with such thermal traps.
The methodology opens the doors to an alternative to burning coal or oil to produce cement or steel, the scientists said. It is thought that the technology could make it possible to use solar energy not only to generate electricity, but also to decarbonise energy-intensive industries on a large scale. this offers the potential to make important industrial applications, such as cement production and metallurgical mining, independent of fossil fuels.
“Our approach significantly improves solar absorption efficiency,” says the study’s lead author, Emiliano Casati. “We are therefore confident that this technology will support the deployment of high-temperature solar power plants.”
The new thermal trap was presented in the paper “Solar thermal energy collection at 1,000 °C and above”, which was published in the latest edition of the scientific journal Device. Detailed technical and economic analyzes are still pending, as such work was beyond the scope of the current experimental investigation.
“To combat climate change, we need to decarbonize energy in general,” Casati added. “People often think of energy in terms of electricity, but we actually use about half of our energy in the form of heat.”
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