Climate Insider Brief:
- Industrial processes like cement, metal, and chemical production require extremely high temperatures, traditionally achieved by burning fossil fuels, leading to substantial greenhouse gas emissions.
- These processes are difficult to decarbonize due to the efficiency needed at such high temperatures.
- Researchers at ETH Zurich, led by Emiliano Casati and Aldo Steinfeld, have developed a thermal trap using a quartz rod and ceramic absorber that efficiently converts sunlight into heat.
The production of cement, metals, and many chemical commodities requires extremely high temperatures, often exceeding a thousand degrees Celsius. Currently, these temperatures are achieved by burning fossil fuels such as coal or natural gas, leading to significant greenhouse gas emissions. While much of the global economy and society are moving towards carbon neutrality, these industrial processes remain challenging to decarbonize due to the high efficiency required at these temperatures.
Researchers at ETH Zurich have now made a significant breakthrough that could help reduce the reliance on fossil fuels for these processes. They have developed a device capable of using solar radiation to generate the necessary heat at high temperatures. The team, led by Emiliano Casati from the Energy and Process Systems Engineering Group and Aldo Steinfeld, Professor of Renewable Energy Carriers, has created a thermal trap that efficiently converts sunlight into heat.
This thermal trap consists of a quartz rod coupled with a ceramic absorber designed to absorb sunlight and convert it into heat efficiently. In their lab-scale experiments, the researchers used a quartz rod measuring 7.5 centimeters in diameter and 30 centimeters in length. By exposing the rod to artificial light with an intensity equivalent to 135 times that of natural sunlight, they were able to reach temperatures of up to 1050 degrees Celsius. This is a significant improvement compared to previous studies, where similar thermal traps achieved a maximum of 170 degrees Celsius.
While large-scale solar concentrating technologies already exist for solar power generation, typically operating at up to 600 degrees Celsius, they suffer from increased radiative heat losses at higher temperatures, which reduces efficiency. The thermal trap developed by ETH Zurich researchers addresses this issue by minimizing radiative heat losses, thus improving the efficiency of solar absorption.
“Our approach significantly improves the efficiency of solar absorption,” says Casati. “We are, therefore, confident that this technology supports the deployment of high-temperature solar plants.” However, the team notes that detailed technical and economic analyses are still required and were beyond the scope of the current experimental study, which has been published in the scientific journal Device.
Casati is continuing his research to further optimize the process. He envisions that this technology could eventually enable the use of solar energy not only for electricity generation but also to decarbonize energy-intensive industries on a large scale. “To combat climate change, we need to decarbonize energy in general,” 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.”
The development of this high-temperature solar technology by ETH Zurich researchers represents a promising step towards reducing industrial reliance on fossil fuels and contributing to a more sustainable, carbon-neutral future.
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SOURCE: EurekAlert!Featured Image: Credit: ETH Zurich / Emiliano Casati
