District heating systems (DHs) are identified as key systems to achieve a de-carbonized supply of heating energy in European Cities, as they allow the efficient integration and balancing of various sources of renewable and waste heat sources with high levels of efficiency and economies of scale. Yet, DHs only corresponds to a market share of roughly 12% of the EU heating market today. In order to increase that number, innovative solutions and technology demonstrations are needed to pave the way for expanding and modernizing existing DH networks as well as introducing and establishing DHs in emerging EU markets.

One way to achieve this evolution is by reducing the heat intensity in districts with the progressive transformation of the building stock to Nearly Zero Energy Building (NZEB) standards, with Positive Energy Buildings being increasingly common. Low (LT) and Ultra-low (ULT) temperature district heating (DH) systems present fewer technical constraints to incorporate low-grade heat sources. Also, they operate at substantially lower costs due to fewer heat losses, better energy performance of heat generation plants, which is further improved by the use of de-carbonized energy sources at low marginal costs. In the process to substitute present DH networks with LT (50-55ºC) and ULT (~45ºC) DHs, critical issues such as treatment against legionella, adequacy of heat delivery systems, methods to directly inject RES into the district energy network, etc. need to be solved.

RELaTED aims at solving these issues by providing a demonstrated concept of ultra-low temperature network solution for new district heating systems and by implementing the progressive conversion of systems already in operation.

What are the actions foreseen by the project?

  • RELaTED will be demonstrated in four different DH networks comprising different countries, climates and network scales (Denmark, Estonia, Serbia, Spain).
  • 2 regional studies will be performed to assess the feasibility of introduction of ULT DH in two Central and South EU regions.
  • In the transition to the RELaTED ULT concept, conversion route maps and hybrid schemes will ensure successful conversion of DHs already in operation, by progressive ULT conversion of subnetworks, and main heat distribution infrastructure, guided by progressive conversion of substations for each consumer, in order to ensure continuity of service.
  • Energy planning processes will allow the selection of suitable urban areas for the integration, extension and/or development of new ULT DH networks, with better cost/benefit scenarios.

The project will interact with an array of other EU funded projects focusing on developing sustainable heating and cooling solutions in Europe.


Get the latest reports

District Heating De-Carbonisation in Belgrade. Multi-Year transition plan

This paper, presented at Beyond 2020 digital event, summarizes the renovation plans for the District Heating network of the city of Belgrade.

Energy meters in DH Substations for Heat Consumption Characterization and Prediction Using Machine-Learning Techniques

In this paper, an intuitive and clarifier data-driven model is presented, which couples heat demand and weather variables.

Data-driven process for the energy assessment of building envelope retrofits

In the paper “Data driven process for the energy assessment of building envelope retrofits”, a novel method is proposed based on whole-building heat load assessment by means of heat meters, and analytical calculations of building envelope transmission heat load coefficients.

Energy & economic assessment of façade-integrated solar thermal systems combined with ULTDH

Energy & economic assessment of façade-integrated solar thermal systems combined with ultra-low temperature district-heating.


RELaTED in the news

RELaTED present at the Sustainable Places 2020

Join RELaTED and 7 sister projects to learn more about the integration of renewable technologies in District Heating and Cooling.

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District Heating De-Carbonisation in Belgrade. Roadmap.

Discover the renovation plans for the district heating network of Belgrade, one of the biggest in Europe

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Iurreta site turns into an ultra-low temperature system

The new ultra-low temperature network in Iurreta will increase the efficiency of the existing heat plant reducing the energy bill and the CO2 emissions in the building complex.

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RELaTED took part in Celsius talk on low temperature heating systems!

The RELaTED project was showcased during Celsius Webinar on Low temperature district heating!

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Intervention plan in Belgrade’s district heating system

Know more about the different interventions to be performed by the RELaTED project

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