Mitigating climate change with district heating innovation

27 Jun 2022

Turku (Finland)

The world is getting warmer and it is an indisputable fact that we all need to significantly reduce our carbon dioxide (CO2) emissions to better protect our planet. So, what part can GEA play by applying our technology to collaborative district heating projects?

In countries around the world, the debate about CO2 emissions rages on. Just last year at COP26 in Glasgow, UK, dozens of governments reaffirmed their commitment to reducing their emission levels by any means possible. Alongside the significant environmental pledges made by food processing and other influential industries that are responsible for a large proportion of harmful emissions, district heating systems are rapidly becoming a go-to solution to tackle CO2 release beyond just a home or a business to an entire locality.

Heat pumps are nothing new; but, with the rapid rise in the use of renewable energy, they have taken on increased importance in the battle against CO2 emissions. Combine this highly efficient method of heat conversion with initiatives to develop district heating systems for domestic and municipal buildings and you have a potential revolution in the making. Add to this the increasing use of natural refrigerants, such as ammonia, and all the technology is in place for a genuinely “green” communal heating solution.

Unnecessary reliance on gas

According to Eurostat, 27.2 percent of all energy in Europe is used by domestic households. Of this, almost 80 percent is used for hot water and heating.1 A recent survey (March 2022) by Statista showed that 87 percent of domestic heating in the UK was by gas.2 Add to this all the civic buildings — including offices, libraries, courts, swimming pools, schools, etc. — and the level to which we humans rely on gas to keep us warm is extraordinary.

But, according to Kenneth Hoffmann, Product Manager Heat Pumps, GEA Heating & Refrigeration Technologies, this is totally unnecessary: “If your house is kept at a regular temperature between say, 18 to 21 °C, there is no need to burn gas at 600 °C to make it comfortable. Using heat pumps, we can boost the temperature of air brought in from outside to make your home very comfortable without using any gas.”

If the same concept was applied to a number of houses, it would be a significant step towards reducing our overall emissions; do it on an industrial scale, for entire districts and communities, and you have a game changer!

Why are heat pumps better?

If we are decarbonizing the generation of electricity, but a heat pump runs on electricity, how can it be better than the status quo? Kenneth Hoffmann explains that the electricity system simply could not cope. “It would never be able to supply the increased power requirement,” he says. “But by using heat pumps which generates up to five times more heat energy per kWh usage of primary energy (electricity) compared to burning gas or direct electrical boilers, the total electrical usage can be kept within acceptable limits.”

As electricity is increasingly generated from renewable sources, a heat pump installed today will have a smaller carbon footprint every year until the electricity is from 100 percent renewable sources. “By combining energy efficiency with burning less gas, we can achieve the decarbonization of society that we desire,” adds Kenneth.

The district heating system

A modern, efficient district heating system, using ammonia-based heat pumps, takes the concept to its best possible conclusion. With a small input of (ideally renewable) electricity, such a solution has the ability to generate heat from a wide range of sources, including the air, the ground, a factory, a subway network or a water treatment plant, to name just a few. This can then be boosted to temperatures of up to 95 °C to supply heating or hot water (or both) directly to the neighborhood.

The system works best in areas with a high population density and makes most economic sense when installed during the initial development of an area or during major infrastructure projects — although this is not a prerequisite. In Malmö in southern Sweden, for example, there are four GEA 10 MW heat pumps installed next to a sewage treatment plant and a waste incinerator near the harbor. They now provide 8 percent of the total energy usage of approximately 100,000 homes, saving close to 50,000 tons of CO2 every year.

GEA raises the bar for standard heat pumps to +95 °C

GEA raises the bar for standard heat pumps to +95 °C

GEA technology and the importance of ammonia

The use of ammonia is a key advancement in the development of district heating technology. Many older systems still use fluorinated (F-) gases for refrigeration, which are being phased out throughout Europe. Unlike F-gases, ammonia is climate friendly, widely available, inexpensive and has no impact on global warming. GEA has been at the forefront of the development of this technology in recent years.

Having first investigated and perfected the methodology, GEA’s engineers then applied the technology in ways that really make a difference in terms of serving local communities better and drastically reducing the level of CO2 generated by utilities.

GEA is constantly innovating to increase its heat pump portfolio and stay ahead of the district heating curve. We will shortly be unveiling yet more advancements in this ground-breaking technology, including an order recently secured for a 22 MW heat pump in Eastern Europe, which includes our new high-pressure screw compressor.

The technology at work

For now, let’s look at some incredible innovations that are already helping the environment. The huge Marienlyst ice rink in Drammen, Norway, provides a competition-standard skating surface during the winter with a 400 m racing circuit and a full-size soccer pitch in the summer. The heat extracted when forming the ice is boosted by GEA heat pumps, which is subsequently used to supply the local town with heat. When summer comes, the temperature under the pitch is raised and the heat pump operate as a ground source heat pump to provide the houses with carbon-neutral hot water.

Meanwhile in Turku, Finland, GEA has supplied a 10 MW district heating system using the residual heat from a combined heat and power plant. The ammonia heat pumps boost the heat from around 25 °C up to 85 °C to supply the city’s 190,000 residents via the domestic heating grid. Again, other than a small addition of electrical power, which is increasingly derived from renewable sources, the whole process is carbon neutral.

In the London Borough of Islington, Bunhill Heat and Power Network (BHPN) uses waste heat from the London Underground — boosted by GEA heat pumps — to supply heating and hot water to around 1350 homes, a school and two leisure centers. It has seen as a major contribution to the Borough’s aim of becoming carbon neutral by 2030.

These are just a few examples of the tireless work that GEA engineers do, every day, all over the world, to bring the benefits of GEA’s ammonia-powered heat pumps to district heating systems.

GEA heat pump in Islington, London

GEA Heat pump installed at Bunhill 2 Energy Centre to reuse waste heat from London Underground.

Action not words

Heating accounts for more than half of global energy consumption, so there is no doubt that it plays a huge role in CO2 emissions.3 We cannot underestimate the importance of integration and a systems-led approach to dramatically upscaling renewable energy with heat that would otherwise be wasted. Equally, phasing out coal and other fossil fuels while innovating for the future is an absolute imperative. The use of heat pumps in district heating not only helps the global environment, it also has local effects; unlike gas boilers, heat pumps do not emit nitrogen oxides (NOx). They therefore lead to cleaner air in cities and other urban areas — and also offer financial advantages.

Let’s return to those global commitments to the environment; according to COP26, if the global temperature were to rise by 2 °C, there would be a severe and widespread impact on both people and Nature. At 1.5 °C, the effects would be serious but less severe. The latter target currently remains in place and it is open to debate whether even more stringent demands will be made in the future.

A sustainable strategy

GEA is already on the case — and has been for many years. Our Sustainable Energy Solutions (SEnS) initiative plays a key role in that strategy by revolutionizing the integration of processes and utilities (cooling and heating) to force down energy consumption, reduce carbon footprints and slash costs across multiple sectors.

Collaboration and innovation are essential parts of tackling the climate challenges that lie ahead, hence our multimillion-Euro investment in new test centers that will come online in 2023. These will be home to cutting-edge rigs that use natural refrigerants, are 90 percent automated, can operate 24/7 and are Industry 4.0 ready.

District heating systems powered by GEA heat pumps are just a single part — albeit a significant one — of the whole solution. In addition, we should never underestimate the power of persuasion: if a householder sees their energy bills and emissions reducing as a result of a district heating system, they are more likely to get behind other sustainable initiatives and encourage big business to be part of the solution, not the problem.

If the world is to achieve its carbon goal of net-zero by 2050, time is running out. GEA has the knowledge, the technology and the ability to successfully implement projects to generate cleaner heating solutions that help to ensure compliance with current and future emissions targets and make a genuine difference to the environment for tomorrow’s generations.

Decarbonizing district heating with heat pump technology


Join GEA’s Cooling Club webinar on District Heating entitled “Decarbonizing district heating with heat pump technology”. Svend Vinther Pedersen, Senior Consultant from The Danish Technological Institute and GEA district heating expert Kenneth Hoffmann will provide their insights on how to decarbonize district heating and decrease energy bills with heat pumps.

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