Invention of ‘battery heater’ could make millions of homes gas-free

Researchers believe they can make millions of homes in Europe gas-free in the near future, after inventing a “thermal battery” made from salt and water.

The team from Eindhoven University of Technology say their low-cost, compact battery system is ready for real-world testing and will be a game-changer for the energy transition.

The thermal battery is based on an old thermochemical principle, namely that when water is added to salt, it produces heat. The reverse is also possible, where the heat can be used to evaporate the water, thus storing the heat energy inside the salt.

Storing the heat in the dry salt makes the battery completely lossless, providing an incredibly efficient way to store energy for future use. This is particularly useful when the energy supply comes from renewable sources, such as wind and solar, which tend to fluctuate widely and therefore require gas or other sources to supplement them.

It took 12 years to develop and create a battery design that could actually work on a large scale, with researchers saying it comes at a critical time as European countries seek to wean themselves off Russian gas after the invasion of Ukraine .

The heat source to be stored in the salt can come from industrial by-products, such as residual “waste heat” from factories or surplus heat from data centers.

“If industrial waste heat could be used to heat homes, you have a win-win situation: homes could be made gas-independent – ​​an even more urgent need given Russia’s reliance on gas – and CO2 emissions would be reduced,” Eindhoven University of Technology said in a statement.

The system is composed of a heat exchanger, a fan, an evaporator/condenser and a salt particle boiler. Despite its simplicity, the proof of concept was able to heat an average family of four for two days.

Engineers have since upgraded it to a fully functional prototype, the size of a large cabinet, that could be used in the real world. With nearly 30 times the storage capacity, the system could heat a home for up to two months.

The thermal battery prototype developed by Eindhoven University of Technology

(Vincent van den Hoogen)

“It’s not yet a product, but everything is now ready to be tested for the first time in a real situation,” said Olaf Adan, a professor at Eindhoven University of Technology.

“While the potential is great, we have also seen many technologies with great potential that have not succeeded, so we will keep our feet on the ground and take it one step at a time.”

A pilot is already being set up to test the technology later this year in homes in France, Poland and the Netherlands.

If successful, Professor Adan says it could be used to wean millions of homes off gas in the near future.

“In the Netherlands we have about 150 PetaJoule [a number with 15 zeros] waste heat from industry per year,” he said.

“That would allow you to take almost 3.5 million homes off gas, which is more than double the Dutch government’s target of 1.5 million gas-free homes by 2030.”