Electrifying industry with flexible heat pumps—a new approach may help companies generate carbon-free process heat

Whether or not producing meals, drinks, medicine, metals or paper or treating surfaces and textiles, industrial firms want course of warmth for a lot of purposes. A lot of that is nonetheless generated by burning fossil fuels. Consequently, the technology of course of warmth accounts for a big proportion of greenhouse fuel (GHG) emissions within the world industrial sector. In Switzerland, it’s liable for some 8% of complete GHG emissions.

The commercial sector might already be producing course of warmth of as much as 200 levels Celsius in an eco-friendly method, utilizing industrial heat pumps that run on electrical energy generated from renewable sources. But regardless of this potential, warmth pumps are nonetheless unusual in industrial settings. It is because present fashions are typically costly constructions which can be custom-made for a particular industrial utility and temperature.

Now, researchers from ETH Zurich and the Jap Switzerland College of Utilized Sciences in Buchs have developed an answer that permits warmth pumps to generate warmth cheaply and flexibly at numerous temperatures of as much as 200 levels Celsius. This suits the sector’s wants way more intently than commercially out there options, which is why quite a few Swiss and worldwide firms have already expressed an curiosity within the expertise. The examine is printed within the International Journal of Refrigeration.

Harnessing warmth from the surroundings

Warmth pumps harness the vitality saved in waste heat or within the ambient air, groundwater or soil. They generate warmth for heating or course of warmth by evaporating a refrigerant fluid in a closed system after which passing the fuel by way of a compressor to extend its temperature. The warmth obtained on this course of can then be used to warmth buildings or for industrial processes.

In typical warmth pumps, the achievable temperature and temperature profile are largely decided by the selection of refrigerant. All the warmth pump’s elements—from the evaporator and compressor to the condenser and growth valve—are tailor-made to this refrigerant.

If a manufacturing unit requires warmth at totally different temperatures for a number of purposes, this may at the moment be achieved solely by utilizing a number of warmth pumps, every with a special refrigerant. That is each expensive and inconvenient, which is why warmth pumps have did not make headway within the industrial sector.

Refrigerant mix boosts flexibility

André Bardow, Professor of Power and Course of Programs Engineering at ETH Zurich, believes his staff has give you a greater resolution, “Instead of a single refrigerant, we use a blend. This allows a heat pump to use different heat sources and generate different temperature profiles.”

The composition of the refrigerant mix may be diversified to cater to totally different purposes. This can be a key profit for firms: as a substitute of getting to revamp the whole warmth pump every time they want a special temperature, they’ll merely modify the combination, which is way less complicated and cheaper.

The combination itself consists of a conventional refrigerant and one additional part. The temperature profile of the warmth pump is dictated by the ratio of those two components. “In principle, you can have any number of different profiles for industrial processes, as long as the temperatures don’t exceed 200 degrees. That’s the major advantage our technology offers,” Bardow says.

Utilizing a pc mannequin to establish the proper mix

To establish appropriate elements for the refrigerant mix, the researchers developed a computer model that simulates the heat-pump circuit with totally different variants of refrigerant combination. “We extended the existing thermodynamic models for heat pumps by integrating the heat-pump components as well as the composition of the mixture into the optimization process,” says Dennis Roskosch, Senior Scientist in Bardow’s analysis group.

The researchers’ mannequin attracts on over 200 million identified artificial molecules to simulate a mix of two molecules that gives essentially the most environment friendly heat-pump efficiency.

Preliminary companions for pilot plant

As soon as the researchers discovered the optimum refrigerant mix, they confirmed its properties within the heat-pump laboratory on the Jap Switzerland College of Utilized Sciences. “The tests showed that our mixture increases the efficiency of a commercially available industrial heat pump by up to 25%, just as we predicted,” says Professor Stefan Bertsch, who heads up the heat-pump laboratory. The researchers had been additionally in a position to reveal how totally different compositions of the refrigerant combination have an effect on the temperature profile.

The staff now hopes to supply much more concrete examples of how their expertise may benefit particular industrial purposes. The brand new warmth pump is more likely to be of explicit curiosity within the meals, pharmaceutical and chemical industries, the place quite a few processes require temperatures of lower than 200 levels.

On the similar time, the researchers are working intently with heat-pump producers akin to MAN Power Options or Scheco AG and with Swiss {industry} companions akin to Lindt. The subsequent step is to plan and construct a pilot plant to hold out additional assessments.