Salt and water vapor are used for the heat battery, explains Olaf Adan, professor of applied physics at Eindhoven University of Technology. “If you bring them together, heat is released. But you can also separate them from each other.”
No heat loss
By adding heat, the water evaporates and you heat the salt dry. “As long as no water gets to this dry salt powder, the heat remains stored in it. Unlike other types of heat storage, nothing is lost,” he tells EditieNL.
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You can charge the battery in places with a lot of residual heat, such as in power plants. The heat is stored and can be used later in another place, for example in homes or offices. Time or place don’t matter. “And that’s special, because there is no other storage technique that is lossless,” explains Adan. “Normally, heat is lost during transport over long distances.”
Potassium Carbonate
However, the process is not possible with every kind of salt. “We do it with potassium carbonate. It’s non-toxic, non-flammable, and abundantly available. You have to mine potassium chloride and bubble CO2 through it. We get it from Germany, because that’s where one of the major producers of potassium carbonate is.”
Advantages
According to professor Adan, the new heat battery has three major advantages. “It’s greener than other solutions, it’s much cheaper – salt is in stock – and it goes much faster. We don’t have to lay pipes and the heat we use is already there, because it’s residual heat.”
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The first pilot will soon start in Sittard. “In order to be able to do it on a large scale, we still have to achieve a breakthrough on two fronts: to stabilize the salt, we developed a device three years ago. We are now scaling up this process. In addition, it is difficult to obtain financing. to get it done on a large scale.”
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moving salt
Han Slootweg, professor of electricity supply, also sees a challenge. “If you want to get heat from elsewhere, for example from a factory, you have to move the salt grains with trucks. Won’t that be very much?”, he wonders.
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About 20 cubic meters of salt is needed to supply fifty homes with energy for one to two weeks. “So you need a lot of salt for 3.5 million households.”
Still, Slootweg is enthusiastic. “The advantage of such a battery is that it can store heat. The energy that your solar panels generate during the day when you are not at home can be converted into heat. This is stored and you can use it to heat your house in the evening. .”
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