Solar penetration into blast furnaces

Swiss researchers have developed a way to achieve particularly high temperatures using solar energy. For cement and steel production, this so-called “heat trap” offers a much cleaner alternative to coal or oil.

The production of cement, metals and many chemicals requires very high temperatures, often exceeding a thousand degrees Celsius. Currently, these temperatures are typically achieved by burning fossil fuels, but they negatively impact the climate. Heating with green electricity is not an effective alternative for such applications. Therefore, industrial applications are difficult to remove carbon.

But a Swiss breakthrough may change that. Researchers at ETH Zurich have developed a “heat trap” that efficiently collects sunlight and converts it into heat. Sunlight is captured by the ceramic material and transmitted to the quartz rod. Temperatures of up to 1050°C were reached at the end of this rod.

Less radiation

The main advantage of the design is that it reduces heat loss through radiation, which is more difficult with other systems.

“Our approach significantly improves the efficiency of solar energy absorption,” says Emiliano Casati, who leads the research. “We are confident that this technology will enable the deployment of high-temperature solar power plants.”

But before the system can be used in practice, a lot of research is still needed, including economic feasibility.

“To combat climate change, we need to make energy generally carbon dioxide-neutral,” says Casati. “People often think of energy in terms of electricity, but we actually use about half of our energy in the form of heat.”