01 Oct 2017


COOL DH project aim was to find ways of utilizing low-grade waste heat in energy efficient buildings by optimizing Low Temperature District Heating (LTDH) solutions.

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October 2017 – September 2022


COOL DH focused on technology innovations – such as exploiting low grade energy sources and new energy efficient heat distribution pipes – and user installations for low temperature district heating combined with integration of local renewable energy sources.

The objective of COOL DH project was to support cities in their endeavour to plan and deploy new, efficient district heating and cooling (DHC) systems, and extend or refurbish existing ones to higher standards. Thus, it allowed greater uptake of renewables, recovering of excess heat or cold while improving the overall efficiency of the systems.


The COOL DH project succeeded to innovate, demonstrate, evaluate and disseminate technological solutions needed to exploit and utilise sources of very low-grade "waste" heat for heating of energy efficient buildings via Low Temperature District Heating (LTDH) and show how the District Heating systems can be more resource efficient and more energy efficient.

The demonstration covered both new developments and stepwise transition of existing areas with district heating and energy retrofitting of buildings.

Specifically, during the project duration COOL DH has:

  • Shared knowledge in workshops and collected input to adjust the approach/plan for the project
  • Developed new innovative solutions
  • Initiated demos in Brunnshög district of Lund, in Sweden, and in Høje Taastrup, in Denmark
  • Completed the demonstrations in Østerby in Høje Taastrup and Heat pump to LTDH connection at Max IV + demos at Xplorion in Lund
  • Developed construction of prosumer heat pumps in Høje Taastrup and LTDH net in Lund
  • Carried out promotion activities, exploring existing ideas and promoting low temperature district heating to the public, COOL DH team came up with exciting ideas on how to use LTDH in the public space

In Figure 1 instalation of a new kind of plastic pipes is shown. Picture was taken during construction in Lund,  Sweden. The new PE-RT pipes comes with benefits such as less joints and more customized design.

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Figure 1- Workers rolling out new types of  district heating pipes - Lund, Sweden

It is also worth to mention, that saving initiated by COOL DH are valued at 10 GWh p.a. in Brunnshög -Lund and 8.8 GWh p.a. in Høje-Taastrup (when fully exploited). Utilised waste heat can save circa 300 kg CO2/MWh.


The COOL DH consortium consists of the utilities and municipalities of the two cities Lund (SE) and Høje-Taastrup (DK) and leading DH energy specialists as well as leading industrial manufacturers:

COWI A/S (Denmark), Kraftringen Energi AB (Sweden), Høje-Taastrup Kommune (Denmark), Lunds Kommun (Sweden), Lund University (Sweden), Euroheat & Power (Belgium), Logstor A/S (Denmark), Høje Taastrup Fjernverme amba (Denmark), COWI AB (Sweden), Alfa Laval AB (Sweden), Lunds Kommuns Fastighets AB (Sweden)

Useful resources:

Report on demo sites and innovations (3 pipe solutions, PE-RT pipes with leak detection, new type of substation)

Calculator on savings

Design guide for LTDH COOL DH solutions


COOL DH Policy Webinar – 4th July 2022 (recording)

European Technical Webinar – 19th September 2019  (recording)

COOL DH Webinar - From the tradition to the future: the Østerby case (recording)

Virtual tours on demo sites : Lund and Høje-Taastrup)

Webinar on business model



Horizon 2020 research and innovation programme