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Energy technology that cuts emissions

Woman in front of a heat pump.
Monika Ignatowicz, PhD student at the Department of Energy Technology in front of a self-built prototype of a HTHP pump.
Published Jan 29, 2025

The principle and technology are similar to those found in refrigerators, tumble dryers and ice rinks. However, high temperature heat pumps (HTHP) are based on a more advanced and powerful technology that can save energy and radically reduce emissions from both buildings and industry.

"The technology, which is relatively new, is constantly improving and has enormous potential in terms of energy efficiency, but there are still challenges that require further research," says Monika Ignatowicz, PhD student at KTH's Department of Energy Technology.

The development of high-temperature heat pump technology has really taken off in the last 20 years, as the technology has become more and more in demand due to increasing demands for energy efficiency and reduced carbon dioxide emissions in order to protect resources and the climate.

Long tradition at KTH

Conventional heat pumps have been used since the early 1900s, and KTH has a long tradition of research in the field, which has laid the foundation for the development of today's high-temperature heat pumps, in which Sweden and KTH have a strong international position.

The energy demand for heating and cooling in industry and housing is enormous. It accounts for more than 50 per cent of the EU's total energy consumption and is expected to grow. In Sweden, the picture is somewhat different, as we use more energy from renewable sources. In the work on decarbonisation, i.e. phasing out fossil fuels and reducing greenhouse gas emissions, HTHP can make a big difference.

Both the Swedish climate targets and the EU's Fit for 55 climate targets call for a significant reduction in emissions by 2045 and 2030 respectively.

"Existing HTHP technology can meet about 10 per cent of the industry's energy needs and reduce CO2 emissions by about 67 per cent, but in the long term the technology will become even more efficient, depending on how high temperatures can be achieved, " Monika Ignatowicz says.

Powerful energy efficiency

The steel, chemical and food industries are examples of production that relies on high-temperature heating. At present, it is possible to reach about 150 degrees.

"But in the long term we hope to reach 260-400 degrees and a very high level of energy efficiency," .

Another advantage of the technology is that you can take waste heat from one building or industry and reuse it in another.

"Yes, it's about being able to integrate different energy systems and finding ways to trick the system so that you can recover energy and reuse it at a local level - connecting a supermarket to a residential building, for example."

However, there are several challenges for HTHP technology. One is ensuring that refrigerants such as ammonia, carbon dioxide and others can be used in a safe and environmentally friendly way, and the initial investment costs are significantly higher than for conventional heating systems. Energy storage is another issue that could become increasingly important in the long term.

Important in the transition


"We are in dialogue with industry and there is a lot of interest in HTHP and how we can use the technology in existing systems in the future,' says Monika Ignatowitcz, who notes that a complex transition of energy systems is a long process. But instruments such as a carbon tax can also speed up the process, where many other EU countries are lagging far behind Sweden."

Monika Ignatowitcz leads the way up a steel-clad spiral staircase to the laboratory where her HTHP prototype is located. It's the first of its kind - built at a university and big enough to heat and cool a house, so she can test the technology in different areas.

"It's important to test, adapt and then take the next step. In five to ten years' time, HTHP will be an important part of the transition," Monika Ignatowicz says.

The HTHP methodology

HTHP and other heat pumps work by drawing heat from sources such as air, water or waste heat, and then using a compressor to increase the pressure and temperature of the refrigerant, such as ammonia or carbon dioxide, which is used to transport the heat.The temperature is then raised very sharply - up to 150 degrees in the case of HTHP.The refrigerant is used as a working medium in refrigerators, freezers, heat pumps and air conditioners, among other things.

On greenhouse gas emissions

The EU will achieve climate neutrality and net negative emissions by 2050 and will reduce its net greenhouse gas emissions by at least 55% by 2030 compared to 1990.The common climate targets also include the combined development of carbon dioxide emissions and removals in forests and soils. According to Sweden's climate target, greenhouse gas emissions from Swedish territory should be at least 85% below 1990 levels by 2045.

Text and photo: Jill Klackenberg

Page responsible:redaktion@kth.se
Belongs to: About KTH
Last changed: Jan 29, 2025