Scientists harness the solar power to generate heat above 1,000°C

Thermal-trapping device reaching 1050 degrees Celsius. Credit: Device/Casati et al.

Researchers in Switzerland have found a way to use solar power instead of fossil fuels to generate heat above 1,000°C, which could revolutionize industries like steel and cement production.

This groundbreaking study, published on May 15 in the journal Device, uses synthetic quartz to trap solar energy, showing its potential to provide clean energy for industries that typically rely on fossil fuels.

“To tackle climate change, we need to decarbonize all forms of energy, not just electricity,” says Emiliano Casati of ETH Zurich, Switzerland. “About half of the energy used today is in the form of heat.”

Industries that produce materials like glass, steel, cement, and ceramics require extremely high temperatures, often over 1,000°C.

These processes currently depend heavily on burning fossil fuels, which contributes significantly to global energy consumption and carbon emissions.

Researchers have been exploring solar power as a cleaner alternative. Solar receivers, which use thousands of mirrors to concentrate sunlight and generate heat, have shown promise. However, efficiently transferring solar energy at temperatures above 1,000°C has been challenging.

Casati and his team have developed a new method to improve the efficiency of solar receivers using semitransparent materials like quartz. Quartz can trap sunlight through a phenomenon called the thermal-trap effect. The team created a device by attaching a synthetic quartz rod to an opaque silicon disk, which acts as an energy absorber.

When exposed to intense sunlight, equivalent to the light from 136 suns, the absorber plate reached a temperature of 1,050°C, while the other end of the quartz rod stayed at 600°C. “Previous research has only demonstrated the thermal-trap effect at temperatures up to 170°C,” Casati explains.

“Our research shows that it works well above 1,000°C, which is crucial for real-world industrial applications.”

The team also used a heat transfer model to simulate the quartz’s thermal-trapping efficiency under different conditions. Their findings showed that thermal trapping could achieve the target temperature at lower sunlight concentrations or higher efficiency at the same concentration.

For example, a modern solar receiver has an efficiency of 40% at 1,200°C with a concentration of 500 suns. The new receiver, shielded with 300 mm of quartz, achieves 70% efficiency at the same temperature and concentration.

Casati and his colleagues are now working to optimize the thermal-trapping effect and explore new applications for the method. They have also experimented with other materials, fluids, and gases to reach even higher temperatures. The ability of these semitransparent materials to absorb light or radiation is not limited to solar energy.

“Solving the energy issue is crucial for the survival of our society,” says Casati. “Solar energy is abundant, and the technology exists. To encourage industry adoption, we need to demonstrate the economic viability and advantages of this technology on a large scale.”

This research marks a significant step toward cleaner and more sustainable industrial processes, potentially reducing our reliance on fossil fuels and helping combat climate change.

Source: Cell Press.