Using solar energy to generate heat at high temperatures
The production of cement, metals and many chemical commodities requires extremely high temperatures of over a thousand degrees Celsius. At present, this heat is usually obtained by combusting fossil fuels: coal or natural gas, which emit large amounts of greenhouse gases. Heating with renewable electricity is not an alternative, as this would be inefficient at these high temperatures. Although much of our economy and society will need to become carbon neutral in the coming decades, these industrial processes are likely to continue to be powered by fossil fuels for the near future. They are considered difficult to decarbonise.
Illustration of the experimental thermal trap. It consists of a quartz rod (inside) and a ceramic absorber (outside). Solar radiation enters at the front, heat is generated in the rear area. Visualizations: Casati E et al. Device 2024, edited
Researchers at ETH Zurich have now demonstrated, in the lab, a way to make these industries independent of fossil fuels. Using solar radiation, they have engineered a device that can deliver heat at the high temperatures needed for the production processes. The team led by Emiliano Casati, a scientist in the Energy and Process Systems Engineering Group, and Aldo Steinfeld, Professor of Renewable Energy Carriers, has developed a thermal trap. It consists of a quartz rod coupled to a ceramic absorber which, thanks to its optical properties, can efficiently absorb sunlight and convert it into heat.
In their lab-scale experiments, the team used a quartz rod measuring 7.5 centimetres in diameter and 30 centimetres in length. They exposed it to artificial light with an intensity equivalent to 135 times that of sunlight, reaching temperatures of up to 1050 degrees Celsius. Previous studies by other researchers have achieved a maximum of 170 degrees with such thermal traps.
Large-scale solar concentrating technologies are already established at an industrial scale for solar power generation, for example in Spain, the US and in China. These plants typically operate at up to 600 degrees. At higher temperatures, heat loss by radiation increases and reduces the efficiency of the plants. A major advantage of the thermal trap developed by ETH Zurich researchers is that it minimises radiative heat losses.
High-temperature solar plants
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, detailed technical and economic analyses are still pending, he says. Such analysis is beyond the scope of the current experimental study, which the researchers have published in the scientific journal external pageDevicecall_made.
Casati is continuing his research to optimise the process. The technology could one day make it possible to use solar energy not only to generate electricity, but also to decarbonise energy-intensive industries on a large scale. “To combat climate change, we need to decarbonise 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.”
Journal: Device
DOI: 10.1016/j.device.2024.100399
Method of Research: Experimental study
Subject of Research: Not applicable
Article Title: Solar thermal trapping at 1,000°C and above
Article Publication Date: 15-May-2024
Media Contact
Marianne Lucien
ETH Zurich
marianne.lucien@hk.ethz.ch
Cell: 79 548 62 55
Media Contact
All latest news from the category: Power and Electrical Engineering
This topic covers issues related to energy generation, conversion, transportation and consumption and how the industry is addressing the challenge of energy efficiency in general.
innovations-report provides in-depth and informative reports and articles on subjects ranging from wind energy, fuel cell technology, solar energy, geothermal energy, petroleum, gas, nuclear engineering, alternative energy and energy efficiency to fusion, hydrogen and superconductor technologies.
Newest articles
Innovative 3D printed scaffolds offer new hope for bone healing
Researchers at the Institute for Bioengineering of Catalonia have developed novel 3D printed PLA-CaP scaffolds that promote blood vessel formation, ensuring better healing and regeneration of bone tissue. Bone is…
The surprising role of gut infection in Alzheimer’s disease
ASU- and Banner Alzheimer’s Institute-led study implicates link between a common virus and the disease, which travels from the gut to the brain and may be a target for antiviral…
Molecular gardening: New enzymes discovered for protein modification pruning
How deubiquitinases USP53 and USP54 cleave long polyubiquitin chains and how the former is linked to liver disease in children. Deubiquitinases (DUBs) are enzymes used by cells to trim protein…