The development of solar reactors is crucial for a future where energy will be 100% clean. This is assured by the international scientific community, which has just taken a promising step in this direction. He did it with the CONTISOL design, as a new solar reactor that operates even at night, with air and without emissions. For this, the experts opted for an innovative approach: the combination of concentrated solar energy and thermal energy storage.
In this sense, the idea on which this new model was built is none other than that of build two reactors in one. “In one, sunlight directly effects chemical processes, and in the other, energy is stored”. Explains Justin Lapp, leader of this project Powered by the German Aerospace Center (DLR) and the Greek laboratory CPERI / CERTH. With this sum of technologies, what has been achieved has been, among other things, to overcome one of the greatest shortcomings of solar reactors. “The problem was knowing what to do at night when the sun is not shining, or even on a cloudy day”. The problem was not minor since, when the temperature dropped, not only was the residual heat of these technologies wasted, but it had to be restarted, from zero, every morning.
To avoid this, they opted for concentrated solar energy on the one hand. Like the combustion of fossil fuels, but without impact, this alternative makes it possible to reach the temperature necessary for the chemical processes necessary to, for example, generate hydrogen. So far, everything is up to standard. However, adding energy storage to the above has been essential. With this, a stable temperature is achieved 24 hours a day, whether the sun is shining or not.
But there is more. CONTISOL adds to the conventional elements of a reactor (usually a tower, solar collectors and the reaction chamber) the storage system from which the heat obtained from the air is transferred to allow chemical reactions. For this, an outdoor receiver is used which, according to experts, “Opens the range of options for high efficiency storage systems, such as thermochemical”.
The fact that it went in the air has more strengths as there are few alternatives as accessible, available, and abundant as this one. In addition, the fact that it is not corrosive is another step forward in terms of costs and safety. Without consequences for leaks, the new model makes the existence of a closed circuit unnecessary. The system “Can collect air from the atmosphere and direct it to the heat exchanger to store heat. Then, once the air has cooled, it can be returned to the outside “.
The potential benefits of this technology for solar fuel production are indisputable. Therefore, the work of experts does not stop after testing their first prototype. The good news is that in laboratory tests, this reactor was able to operate at 850 degrees and with a capacity of 5 kW.
The team itself, which has limited testing to obtaining methane, is the one indicating that there is still work to be done to improve solar reactors. “This scale is only a prototype for understanding how to control the reactor. It would not be marketed with 5 kW “Stresses Lapp. “Commercially, between one and 5 MW would be the minimum for industrial scale reactors, and these could reach 100 MW”, he argues. Besides the size, the field is also vast in terms of solar fuels to obtain, especially hydrogen, as well as many others.
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