Heat pumps in district heating systems

In a new report from the European Celsius Initiative the integration of large-scale heat pumps in future district heating systems is examined. The combination of district heating and heat pumps are foreseen to have a key role in the future energy systems and future district heating systems are predicted to have a larger number of heat pumps installed in the grids compared to today.

Scenarios made by the project Heat Roadmap Europe shows that with an expansion of district heating, it is possible to cover up to 50% of the heating demand in Europe with district heating and around 25% of the energy to the district heating grids will come from heat pumps1. The project shows different scenarios, all including a larger share of district heating. The scenarios show the potential of reducing the CO2 emissions from the European heating sector with more than 70% compared to the current situation.

The reason why heat pumps are foreseen to increase in district heating system is because heat pumps can deliver heat with high efficiency and at the same time create a link between the heating and electricity sector utilizing intermittent renewable energy sources. It enables for an overall decarbonisation of the energy system and the possibility to make district heating an integrated part of a smart energy system. To have an efficient integration of variable renewable sources, the heat pumps would have to operate in a flexible way. Most of their capacity should be used during hours when wind and solar electricity are available. When the demand is low, they can be used to fill up thermal storages with heat. This will allow for further integration of intermittent renewables.

The integration of large-scale heat pumps in future district heating systems are important for multiple reasons:

  1. Heat pumps combined with storage systems have the potential to become a key technology since it enables for future district heating systems to balance the power grid when the production of electricity from intermittent renewable energy sources fluctuates.
  2. Heat pumps makes it possible to utilize excess heat of low temperatures and reduce grid losses.
  3. Heat pumps increase the flexibility of district heating systems, by utilizing multiple sources of heat, it enables higher flexibility of the energy system. Fast commissioning and low start-up costs are some of the benefits with heat pumps, as well as taking advantage of the volatility of the electricity market and the possibility to use the thermal grid and storages as thermal batteries.
  4. Heat pumps play an important role in integrating more renewable energy and phase out fossil fuels from the energy systems.

Text by: Anton Falk, RISE, Research Institutes of Sweden

Read the report
Summary report on heat pumps in district heating systems > (2021)

New HPT Annex about heat pumps in district heating systems
Annex 57 Flexibility by implementation of heat pumps in multi-vector energy systems and thermal networks

More about Celsius
Celsius, is a collaboration hub for efficient, integrated heating and cooling solutions supporting European cities in their energy transition to carbon-neutral systems.
Read more about Celsius >

Release of IEA’s Net Zero by 2050 Roadmap for the global energy sector

The special report released by IEA on May 18, 2021 shows that the pathway to the critical and formidable goal of net zero emissions is narrow, but it brings huge benefits. The report shows that heat pumps and efficient cooling technologies has an important role in reaching the goal.

The pathway requires an unprecedented transformation of how energy is produced, transported and used globally. Climate pledges by governments to date – even if fully achieved – would fall well short of what is required to bring global energy-related carbon dioxide (CO2) emissions to net zero by 2050 and give the world an even chance of limiting the global temperature rise to 1.5 °C, according to the new report, Net Zero by 2050: a Roadmap for the Global Energy Sector.

The report is the world’s first comprehensive study of how to transition to a net zero energy system by 2050 while ensuring stable and affordable energy supplies, providing universal energy access, and enabling robust economic growth. It sets out a cost-effective and economically productive pathway, resulting in a clean, dynamic and resilient energy economy dominated by renewables like solar and wind instead of fossil fuels. The report also examines key uncertainties, such as the roles of bioenergy, carbon capture and behavioural changes in reaching net zero.

Building on the IEA’s unrivalled energy modelling tools and expertise, the Roadmap sets out more than 400 milestones to guide the global journey to net zero by 2050. These include, from today, no investment in new fossil fuel supply projects, and no further final investment decisions for new unabated coal plants. By 2035, there are no sales of new internal combustion engine passenger cars, and by 2040, the global electricity sector has already reached net-zero emissions.

In addition, other defined key milestones, are “no new sales of fossil fuel boilers by 2025” and that “50% of heating demand is met by heat pumps in 2045”, see Figure 4.1 below (page 152 in the report). The share of existing buildings retrofitted to the zero‐carbon‐ready level need to increase from <1% in 2020 to 20% in 2030 and >85% in 2050. The corresponding share for new buildings must be 100 % already in 2030. The stock of installed heat pumps needs to increase from 180 million units in 2020 to 600 million units in 2030 (almost quadruple) and thereafter a tenfold increase to 1800 million units in 2050, see the Figure 3.29 below (page 145 in the report).

Fig 3.29 Global building and heating equipment fr IEA report 2021


Fig 4.1 from IEA report NetZero by 2050

Most of the global reductions in CO2 emissions between now and 2030 in the net zero pathway come from technologies readily available today. But in 2050, almost half the reductions come from technologies that are currently only at the demonstration or prototype phase. This demands that governments quickly increase and reprioritise their spending on research and development – as well as on demonstrating and deploying clean energy technologies – putting them at the core of energy and climate policy.

The special report is designed to inform the high-level negotiations that will take place at the 26th Conference of the Parties (COP26) of the United Nations Climate Change Framework Convention in Glasgow in November. It was requested as input to the negotiations by the UK government’s COP26 Presidency.

The full report is available for free on the IEA’s website along with an online interactive that highlights some of the key milestones in the pathway that must be achieved in the next three decades to reach net-zero emissions by 2050.

Read the press release from IEA and the full report here >

EPA moves forward with phase down of climate-damaging hydrofluorocarbons

The U.S. Environmental Protection Agency (EPA) is to phase down the production and consumption of hydrofluorocarbons (HFCs), commonly used in refrigerators, air conditioners, and many other applications.

The EPA ambition is to sharply reduce production and consumption of these harmful pollutants by using an allowance allocation and trading program.

This phasedown will decrease the production and import of HFCs in the United States by 85% over the next 15 years. A global HFC phasedown is expected to avoid up to 0.5 °C of global warming by 2100.

Read the EPA news release about down phasing of hydrofluorocarbons >

Two new HPT Annexes have started

The Heat Pumping Technology HPT programme is happy to welcome two new Annexes that have been initiated already in January 2021.

Annex 57 focuses on the implementation of heat pumps in district heating and cooling systems. This annex will investigate possible flexibility in the electric grid as well as in thermal networks by the implementation of heat pumps. In addition, possible solutions and barriers for heat pumps on these markets will be examined.

Annex 58 will give an overview of available technologies and close-to-market technologies regarding high-temperature heat pumps. The need for further RD&D developments will be outlined. In order to maximize the impact of high-temperature heat pumps, this annex also looks at process integration by development of concepts for heat pump-based process heat supply and the implementation of these concepts.

Invitation to new participants
HPT TCP welcomes research organisations and industry to participate in Annex 57 and Annex 58. If you are interested to join the Annexes, please contact:

Annex 57

Svend Pedersen, Operating Agent
See Annex 57 web >

Annex 58

Benjamin Zühlsdorf, Operating Agent
+45 7220 1258
See Annex 58 web >

Design and Integration of heat pumps for nearly Zero Energy Buildings

The final report of Annex 49 is now published together with four extensive reports that are focusing on heat pumps in nearly Zero Energy Buildings (nZEB).

The Annex 49 was a follow-on of the work in Annex 40 on heat pump concepts for nZEB, with an extended scope from the balance of single buildings to groups of buildings.

The dominating concept was to reach the zero-energy balance over an annual period for nZEBs.

Annex 49 is sharing experiences on heat pumps in nZEB as well as design of HVAC systems for nZEB in different countries. Development and market situation of heat pump systems in nZEB has also been investigated through this annex that was active during 2016 to 2020.


The results from this project shows that heat pumps can become the standard building technology for nearly Zero Energy Buildings (nZEB). Due to the high performance of heat pumps, nZEB can be achieved cost-effectively. Further on, heat pumps can increase on-site electricity self-consumption and unlock flexibility potentials by smart controls. In this way heat pumps become the backbone of a future sustainable and renewable built environment and energy system.

Read more

Annex 49 has been structured into four parts that are being presented in four reports:

HPT Annex 53 participant – partner in one of the teams who captured Grand Prize in the Global Cooling Prize contest

HPT TCP Annex 53 (participant Baolong Wang (Tsinghua University) partners with Gree Electric Appliances, Inc. (leading Chinese heat pump system manufacturer) to capture Grand Prize in the Global Cooling Prize contest. On April 29, Sir Richard Branson announced the Gree/Tsinghua team as co-winners (along with the Daikin group team) of the Global Cooling Prize contest. The contest began in November 2018 and 139 teams submitted detailed applications in August 2019. From these eight finalist teams were selected. The finalists prepared prototypes of their concepts which were field and lab tested at locations in India between Sept. 2020 to March 2021.

Technology Description

Gree’s innovative Zero Carbon Source cooling technology integrates advanced vapor compression refrigeration, photovoltaic direct-driven technology, evaporative cooling, and ventilation, which efficiently utilizes renewable energy sources and free cooling sources.

The innovative hybrid solution is designed to have an automatic, climate-smart operation in three modes – vapor compression refrigeration, direct evaporative cooling, and ventilation. It can operate individually or in parallel to provide optimized indoor temperature and humidity control according to the weather conditions.

The vapor compression refrigeration system adopts a parallel compression cycle with dual evaporation temperature. It is realized based on a specially-designed triple-cylinder compressor, a low GWP refrigerant, and improved-designed evaporator and condenser. The ventilator, operating in ventilation mode or direct evaporative cooling mode, strives to decrease the indoor cooling load and eliminate the latent load. The energy consumption of the cooling solution can also be decreased by the ventilator even when the outdoor air has a higher enthalpy than the indoor air. A small PV panel is integrated into the power system by a smart modulator for power transformation and distribution.

This climate-adaptive residential air conditioner has 5X lower climate impact than today’s conventional air conditioners. Gree’s cooling solution highlights how the upper efficiency limit of today’s predominant technology—vapor compression technology—can be largely expanded through smart, hybrid design.

More info

Read more about the winning project of Tsinghua University and Gree >

Press release: Breakthrough, Climate-Friendly ACs: Winners of the Global Cooling Prize Announced >

Report: Global Cooling Prize: Solving the Cooling Dilemma >

Read more about Annex 53 >

Launch of the 14th IEA Heat Pump Conference “Heat Pumps – Resilient and efficient”, in Chicago 2023

During the closing ceremony of the 13th IEA Heat Pump Conference, which took place onsite in in Jeju, Korea and online, the 14th IEA Heat Pump Conference was launched by Brian Fricke, the Chairman of the National Organizing Committee. The conference will have the theme “Heat Pumps – Resilient and Efficient” and take place in Chicago on May 15-18, in 2023.

The conference will include workshops, oral and poster presentations, technical exhibits, a banquet, technical tours and an evening social event option as well as a spouse/guest program.

The conference will be held at Renaissance Chicago Downtown Hotel, close to the Theatre district in Chicago. The 10 Must Do’s When Visiting Chicago, the Windy City, including attractions, shopping and dining, were presented during the launch.

Brian Fricke concluded the presentation by welcoming everyone to Chicago in two years.

The winners of the 2021 Rittinger Award

In a ceremony held digitally at the closing session of the 13th IEA Heat Pump Conference in Jeju Korea on April 29 2021, the winners of the prestigious Peter Ritter von Rittinger International Heat Pump Award, the highest international award in the air conditioning, heat pump and refrigeration field were presented.
Jussi Hirvonen, Finnish Heat Pump Association, Professor Ruzhu Wang, Shanghai Jiao Tong University and the Center for Environmental Energy Engineering (CEEE) University of Maryland were given the 2021 Rittinger Award for their efforts in the field.

Jussi HirvonenM.Sc. Jussi Hirvonen, was the initiator of heat pump business in the Finnish market and because of his tireless work, Finland has become one of the leading countries using heat pumps for space heating. Jussi’s 20 years of remarkable lifework in the heat pump sector also includes a large number of commitments in different positions and organizations which have forwarded heat pump business locally and globally. Jussi was the founder member establishing Finnish Heat Pump Association and as well founder member establishing European Heat pump Association (EHPA). He was also one of the members establishing Eesti Soojuspumpa Liit (ESPL) heat pump association into Estonia. Finland participating IEA HPT TCP program was also consequence of Jussi Hirvonen activity.

Yunho Hwang Prof. Ruzhu Wang is full professor and the director of Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University (since 1993). His institute has been recognized a world leading research institute in Refrigeration and Heat Pump Technology. Prof. Wang’s major contributions related to heat pumping technologies include adsorption heat pumps, desiccant based heat pumps and dehumidification, vapor compression heat pumps, absorption heat pumps, and heat pump applications in green building energy systems and industrial waste heat recovery. He has written 12 Books regarding Refrigeration and Heat Pump Technologies (3 in English published by Wiley, Elsevier and Springer respectively). His publications have been extensively cited, thus he has been recognized as 2017 & 2018 Clarivate Highly Cited Researcher in the world.

Center for Environmental Energy Engineering (CEEE), this team of researchers from the Center for Environmental Energy Engineering at the University of Maryland works on cutting-edge heat pump technology research. They have one of the world’s most comprehensive research portfolio on a wide range of heat pumping technologies both in terms of experiments and modeling. This remarkable group of researchers brings a wealth of experiences and expertise to the heat pump research community. Their contributions led to significant gains in technological development. They work collaboratively with researchers from other fields, other countries, and other institutions leading to great breakthroughs in both energy efficiency, improved performance, and reduction of manufacturing and energy costs.

Rittinger Award winners 2021 - Team from Center for Environmental Energy Engineering

Winners of the team from Center for Environmental Energy Engineering: Dr. Reinhard Radermacher, Dr. Yunho Hwang, Dr. Vikrant Aute, Dr. Jiazhen Ling, Mr. Jan Muehlbauer.

The team from the Center for Environmental Energy Engineering that received the 2020Rittinger Award consists of:
• Dr. Reinhard Radermacher, Director of the Center and Minta Martin Professor of Engineering, Professor of Mechanical Engineering
• Dr. Yunho Hwang, Co-Director and Research Professor
• Dr. Vikrant Aute, Co-Director and Research Scientist
• Dr. Jiazhen Ling, Assistant Research Professor
• Mr. Jan Muehlbauer, Faculty Specialist and Laboratory

Pressrelease_Rittinger_Award_2021 >

Opening of the 13th IEA Heat Pump Conference “Heat pumps – Mission for the Green World”

On April 26 the 13th IEA Heat Pump Conference was opened. This is a hybrid onsite-online event. There are about 100 national Korean conference attendees onsite at Ramada Plaza Hotel Jeju in Korea, and in addition, about 260 international participants who attend online.

The conference was opened by Stephan Renz, the Chairman of the Technology Collaboration Programme on Heat Pumping Technologies (HPT TCP) by IEA, who held a welcome address, when he welcomed the participants, gave a brief introduction about the programme and acknowledged those who have contributed to the organization of the conference. Thereafter, Min Soo Kim, the Chairman of the National Organizing Committee held an opening remark when he told the audience that more than 200 papers were going to be presented during the days to follow. In addition, Won Hee-ryong (Governor of Jeju Province) gave a congratulatory address to the conference organizers.

For the plenary speech, six invited speakers from all continents gave their vision on the development of heat pumping technologies.

Mechthild Worsdorfer, IEA Director of Sustainability, Technology and Outlooks talked about “Heat Pumping Technologies in Clean Energy Transitions”. She outlined the three key priorities for heat pumping technologies as IEA see it – deployment across all relevant applications, integration to existing buildings and power systems and that heat pumps should be enhanced to be multi services providers. She also stated that in 2070 heat pumps need to become the market norm for heating equipment and that heat pumps could an and need to be flexibility providers to reach the sustainable development scenario.

Martin Forsén, the President of EHPA told the audience about “the European Legal Framework, which he reported to be well set for a massive roll-out of heat pumps, even though more efforts still are needed to realise this rapid deployment of the technology. Among other things he talked about how the recognition of the technology in European policies had developed during the two last decades. In 2020 the technology was barely mentioned in the EPBD directive, in 2009 the heat pumps were defined as a renewable technology in the Renewable Energy Directive and in 2020, in the Energy System Integration Strategy, heat pumps are described as the most important technology for decarbonisation of buildings. The share of electric based heat is expected to become 40% by 2030 and 50-70% by 2050.

Min Soo Kim, President of SAREK (Society of Air-conditioning and Refrigerating Engineers of Korea) talked about “Korean policy for a green world and heat pumping technologies”. He talked about the Korea New Deal, launched in July 2020, consisting of the Digital New Deal and the Green New Deal. The Green New Deal aims at accelerating towards a transition towards a low-carbon and eco-friendly economy and includes Green Transition of Infrastructure, Low-carbon Decentralized Energy and Innovation in the Green Industry. Examples of activities that will be promoted is integration of more renewable electricity in the grid from solar and wind, the set-up of intelligent smart grid systems for energy conservation and building of smart industries were waste heat are reused. The vision of Korea is to be carbon neutral by 2050 and Min Soo Kim concluded his presentation by stating that heat pumps are essential to the success of the Green New Deal as they can dramatically save heating and cooling energy.

Saikee Oh, Vice President of LG Electronics, Korea held a presentation about “Heat Pump System Technology Trend”. He talked about, current trends in cutting edge technologies to increase the operating range of air source heat pumps to lower ambient temperatures, such as technologies to increase the maximum pressure ratio of compressors, to apply high heating capacity cycles and technologies to enhance oil reliability. In addition, he emphasized that heat pumps are a promising alternative in a wide variety of applications such as home appliances and industrial applications.

Xudong Wang, Vice President of AHRI, USA talked about “Ensuring a Safe Refrigerant Transition”. Such a transition involves regulations, trends, codes and standards compliances, training and stakeholder buy-ins and the presentation explored how the American industry deals with this transition. The content covered the current status on relevant code and standard development, research performed and remaining efforts needed in the transition to low-GWP refrigerants in the future.

Noboru Kagawa, Professor of National Defense Academy, Japan held the final plenary lecture presentation, on the topic “Clean and Safe Air by HVAC systems – Laws and Advanced Technologies in Japan”. Experience of health problems and pandemics changes the design of HVAC systems frequently. Accumulated knowledge which can improve the HVAC technologies and related laws and new technologies in Japan was overviewed. One example was energy efficient heat recovery in ventilation systems applying heat pumping technologies in combination with desiccant systems.

After the opening and plenary sessions, the conference proceeded with a extensive program consisting of three parallell tracks, during three days, including in total 36 sessions with oral presentations and 36 poster presentations.

It is still possible to register for the conference and take part of all the prerecorded presentation online until April 29 2021, at hpc2020.org.

Heat pumps in multi-family buildings – New issue of the HPT Magazine

The first issue of the 2021 HPT Magazine focuses on the possibilities of heat pumps in multi-family buildings. In the topical articles you can read about drivers and barriers for heat pumps as well as the aspects of retrofit projects.

In this issue you also get the latest updates from our Annexes, together with an insight in the big and quite unique market for heat pumps in Finland. The significance of heat pumps has grown in several kinds of buildings and play an important role as a producer of renewable energy.

Read the HPT Magazine 01/2021 >

Annual Report 2020 is here

The Technology Collaboration Programme on Heat Pumping Technologies (HPT TCP) Annual Report for 2020 is now published and can be downloaded.

The Annual Report describes the work of the Programme during 2020 including Message from the Chairman, information about our Annexes, and the highlights of 2020. This and previous Annual Reports can be found in our publication database.

See the Annual Report 2020 >
Search for reports and publications in the HPT database >

Member of HPT Annex nominated for The Global Cooling Prize

The Global Cooling Prize’s virtual Grand Award Ceremony will take place on April 29, 2021. One of the participants of the finalist teams, Baolong Wang of Tsinghua University, is also part of the HPT Annex 53.

We wish Baolong Wang and his team good luck in the final of this award, where AC manufacturer Gree, in partnership with Tsinghua University is presenting an innovative hybrid solution designed to have an automatic, climate-smart operation. In total eight teams are in the final for the Global Cooling Prize.

At the upcoming Grand Award Ceremony, the winner(s) of the Global Cooling Prize will be announced and the winning team(s) awarded with up to $1 Million to support the commercialization of their technology. The Ceremony will feature profiles on each Finalist team, videos of the Prize’s journey, fireside conversations with coalition partners, and special remarks from influential leaders tuning in from around the world. The Ceremony will also highlight what comes next as we Race to Zero in the cooling sector in the lead up to COP26.

This event will serve as an opportunity to recognize the incredible achievements of the Prize participants and global coalition, while also highlighting the ceiling of performance for residential cooling, spurring policymakers, financiers, and industry to support the commercialization and scaling of breakthrough cooling technologies.

Read more about The Global Cooling Price >

Read more about Annex 53 >

Meet the plenary speakers of the 13th IEA Heat Pump Conference

The 13th IEA Heat Pump Conference is providing a program focusing on energy and the environment. Between 26-29 April 2021, experts from all over the world will talk on the subject “Heat Pumps – Mission for the Green World”, digital and on-site in Jeju Korea.

Last chance to register for this event will be on Friday 16 April.

For the plenary speech, six invited speakers from all continents will give their vision on heat pump industry. The first three influential speakers will introduce global heat pump markets and policy followed by three eminent speakers providing excellent summaries on key technologies of heat pump systems.

  • Mechthild Worsdorfer, IEA Director of Sustainability, Technology and Outlooks – “Heat Pumping Technologies in Clean Energy Transitions”
  • Martin Forsén, President of EHPA – “The European Legal Framework is Well Set for a Massive Roll-out of Heat Pumps – but More Efforts are Needed!”
  • Min Soo Kim, President of SAREK (Society of Air-conditioning and Refrigerating Engineers of Korea) – “Korean policy for green world and heat pumping technologies”
  • Saikee Oh, Vice President of LG Electronics, Korea – “Heat Pump System Technology Trend”
  • Xudong Wang, Vice President of AHRI, USA – “Ensuring a Safe Refrigerant Transition”
  • Noboru Kagawa, Professor of National Defense Academy, Japan – “Clean and Safe Air by HVAC systems – Laws and Advanced Technologies in Japan”

The conference will take place on April 26-29, 2021 at Ramada Plaza Hotel Jeju, Korea with an integrated extended online offer for online participants from all over the world. Through the online offer you will have the opportunity to take part of all the highlights of the 13th IEA Heat Pump Conference between the 18th of April until the 1st of May – on-demand when it suites you.

Register and see the whole program here >

Heat pumps key technology in Helsinki Energy Challenge

The City of Helsinki in Finland has arranged a year-long international Energy Challenge to find future-proof solutions to heat the city during decades to come. The competition attracted 252 proposals from 35 countries. An international jury has now selected four winners from the ten finalists in the Helsinki Energy Challenge.

The awarded proposals selected by the jury,  illustrate the diversity of the challenge and the diversity of approaches necessary to achieve a flexible and resilient system. All the winners, presented below, have heat pumps as a key technology in the system solution.

  • HIVE, a flexible plan, based on proven technologies and solutions, such as seawater heat pumps, electrical boilers, solar thermal fields and demand side management measures; the plan is capable of integrating new technologies if and when these emerge.
  • Beyond fossils, an energy transition model based on open and technology neutral clean heating auctions, paving up the path to carbon neutral Helsinki in a flexible and innovation enabling way. According to current technology cost assumptions, the main new technologies would be heat pumps using ground, air, water and excess heat streams as heat sources.
  • Smart Salt City, a solution that melds a novel thermochemical energy storage and artificial intelligence with commercially available energy technologies. We keep the existing DHS as the backbone for the city to which we link several heat sources. One of the new key sources of energy in our proposal is the utilization of waste heat. The largest one of these would be waste heat from the nearby industrial area. In addition, heat pumps utilizing sewage water, other low temperature heat sources, solar, outdoor air and sea water are expected to provide a substantial part of the heat demand.
  • Helsinki’s Hot Heart, a flexible system made of 10 floating reservoirs filled with 10 million cubic meters of hot seawater that can receive different energy sources as input. Four of the cylindrical tanks that make up Helsinki’s Hot Heart would be enclosed with inflatable roof structures to create a new leisure attraction. Electric energy is converted into thermal energy using heat pumps exchanging with the sea. Alternatively, sources of heat are directly plugged into district heating.

All the awarded teams have significant international competence.

Read more about The Helsinki Energy Challenge >