In the future, solar energy could be used to produce cement or steel, i.eInstead of burning coal or oil for this purpose. Researchers at ETH Zurich have developed a heat trap capable of absorbing concentrated sunlight and radiating heat in excess of a thousand degrees. Celsius.
- The new heat trap uses sunlight to reach temperatures above a thousand degrees Celsius.
- New technology minimizes heat loss, enabling efficient generation of this high temperature
- This approach could help provide high temperatures to industrial plants and thus make these industries carbon neutral.
Industrial thermal processes
The production of cement, metals and many chemicals requires extremely high temperatures, over a thousand degrees Celsius. Currently, this heat is generally obtained by burning fossil fuels: coal or natural gas, which emit large amounts of greenhouse gases. Heating with renewable electricity is not an alternative as it would be ineffective at these high temperatures. Although much of our economy and society will need to become carbon neutral in the coming decades, these industrial processes will likely continue to be powered by fossil fuels for the foreseeable future. They are considered difficult to decarbonize.
Breakthrough in solar thermal technology
Scientists from ETH Zurich demonstrated in the laboratory a way to make these industries independent of fossil fuels. Using solar radiation, they designed a device capable of providing heat at the high temperatures required for production processes. A team led by Emiliano Casati, a scientist in the Energy Systems and Process Engineering group, and Aldo Steinfeld, a professor of renewable energy carriers, developed the heat trap. It consists of a quartz rod connected to a ceramic absorber which, thanks to its optical properties, can effectively absorb sunlight and convert it into heat.
In their laboratory experiments, the team used a quartz rod with a diameter of 7.5 centimeters and a length of 30 centimeters. They exposed it to artificial light with an intensity 135 times greater than that of the sun, reaching temperatures of up to 1050 degrees Celsius. Previous studies by other researchers have reached a maximum of 170 degrees with such heat traps.
Large-scale concentrating solar energy technologies have already been implemented on an industrial scale for solar energy production, for example in Spain, the United States and China. These plants usually operate up to 600 degrees. At higher temperatures, radiation heat losses increase and reduce plant efficiency. One of the main advantages of the heat trap developed by ETH Zurich researchers is that it minimizes heat loss by radiation.
High-temperature solar power plants
Our approach significantly improves the efficiency of solar absorption,” explains Casati. “Therefore, we are convinced that this technology supports the introduction of high-temperature solar power plants. » But detailed technical and economic analyzes are still awaited, he says. Such an analysis goes beyond the scope of the current experimental study, which the researchers published in a scientific journal Device.
Casati continues his research to optimize the process. This technology could one day enable the use of solar energy not only for electricity generation, but also for the decarbonization of energy-intensive industries on a large scale. “To fight climate change, we need to decarbonize energy in general,” says Casati. “People often think of energy as electricity, but we actually use about half of our energy as heat. »
To learn more about this research, see Solar Energy Breaks the 1000°C Barrier for Industrial Heating.