Crystals, jets, magnets — is this the green way to cool?

In a world hit by climate change, cooling technology is no luxury. it saves lives, keeping food fresh and ensuring comfort at home or in the office. Between now and 2050, 10 new air conditioners will be sold every second. According to the International Energy Agency.

However, all these machines run continuously for hours and consume enormous amounts of electricity. These devices tend to contain refrigerant gases that are thousands of times more harmful than CO2 in terms of global warming potential.gas gradually leakeven after throwing away old air conditioning units and refrigerators.

Ironically, cooling oneself to survive climate crisis It can actually make the problem worse. That’s why there are multiple startups. EuropeBut all over the world, we are researching new technologies that can make cooling much more efficient than it is today. And they come up with some unusual ideas.

No liquids, no leaks

Barocal co-founder Xavier Moya has a prototype machine in his Cambridge lab that applies pressure to plastic crystals, lattices of organic molecules. This creates a strong cooling effect, lowering the temperature by, for example, 20 or 30 degrees Celsius.

“We don’t use gas, so it doesn’t leak,” says Moya. Barocal currently has six employees and to date he has raised £1.5m. fundraising.

This technology is based on the fact that molecules in solid refrigerants naturally rotate, but stop when pressure is applied. “When you remove the pressure, the molecules try to rotate again and have to absorb energy, which is why they cool,” says Moya.

He added that the process is a bit like what happens inside liquid crystal displays. Such displays contain molecules such as: Changes direction when an electric field is appliedFor example, you can see the numbers appear on the calculator screen.

Barocal’s solid refrigerants have the potential to be used inside air conditioners and refrigerators, on both domestic and commercial scales, Moya said. He claims the system will be very efficient. In heating and cooling systems, one kilowatt hour (kWh) of electricity is often used to produce several kilowatt hours of heat energy, known as the coefficient of performance (COP). For example, with a modern heat pump, at home he could get COP 3. This means that 3 kWh of heat is produced for every 1 kWh of electricity consumed.

“We hope to more than double the efficiency,” says Moya, adding that it will still be years before his company releases a commercial product.

Another start-up looking to do away with refrigerant fluids is Poland’s Dynamic Air Cooling. The company employs 13 of his people and has raised €3.5 million in funding, of which €2.3 million is being used for grants.

“Mini Tornado”

Co-founder and CEO Pavel Panajuk said he came up with the idea more or less by accident when his team was experimenting with the same technology used in jet engines.

“We created a process that is a lot like a mini-tornado,” he says. The twisting and turning of the air converts the heat energy in the air into kinetic energy instead, creating a cooling effect, he said. The system can reliably lower temperatures by about 45 degrees Celsius, Panasjuk added, and in his experiments it worked with starting points ranging from 0 degrees Celsius to about 35 degrees Celsius.

One of the difficulties is that there is currently no definitive way to determine a specific output temperature, so the team is working on developing a control unit for it. “There is a solution,” hinted Panajuk, adding that the system should achieve a he COP of about 4.

He added that once all the engineering challenges are solved, Dynamic Air Cooling can be commercialized within a year from today. The company targets industrial refrigeration for food storage and transportation.

Germany’s Magnoterm is also determined to make its refrigerators greener, but with a completely different kind of technology. Co-founder and managing director Timur Silman explains that his startup’s device relies on rotating magnets. Imagine he has two things like burger buns above and below the “burger”. In this case, the burger is a special iron alloy with many pores through which water can be pumped. The magnetic field produced by the rotating magnet has the effect of cooling the metal alloy and thus the water passing through it.

Pursuit of efficiency

The company, which employs 32 people, has raised 6.3 million euros to date and has already developed a refrigerator, a small commercial product that it rents to event organizers. Dubbed the Polaris, the refrigerator can hold 100 to 200 drinks, but with a COP of only 1, it’s not very efficient, Thurman said. However, he added, this could be fixed by making the refrigerator bigger.

“The cooling power changes in proportion to the amount of material you put inside,” Thurman says. So by using the same motor and water pump, but using more porous iron alloys, the team hopes to achieve even more cooling and his COP of up to 5 by 2024.

In principle, the same technology could also be used for air conditioning systems, but Magnotherm does not focus on that at the moment. The company’s system is expected to be used in commercial refrigerators as a modular unit that can be pulled out and installed in a new refrigerator whenever a customer, such as a supermarket, decides to update the hardware.

Nicole Miranda, a researcher in the Future Cooling Program at Oxford Martin School, part of the University of Oxford, said it was “amazing” to see so much innovation in the field of cooling. She stresses that in the next few years, passive cooling technologies, from fabrics that keep the body cool to increased shade in urban centers, will become as important as those that require electricity.

However, the demand for air conditioners and refrigerators is truly enormous around the world, so it is important to develop sustainable systems now that do not consume excessive energy or are built with materials that have a high carbon footprint. , she added.

Consider also the many homes located throughout Europe. Not designed to protect against excessive summer heat. And it is not yet clear whether such national energy systems will be able to meet the burgeoning demand for cooling technology over the next few years.

“The simple solution is to go to the store and buy an air conditioner,” says Miranda. “That’s a big risk for the power grids in those places.”