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Terms for 5GDHC/anergy networks

There are many different terms for 5GDHC/anergy networks. On this page, you will find an overview of the most common terms for 5GDHC networks.

General terms in energy engineering and research

  • Cold district heating networks: The term cold district heating (in German: kalte Nahwärme) is very common in German-speaking countries.
  • Anergy network: Especially in Switzerland but also in Germany and Austria, the term "anergy network" is very common.
  • 5th Generation District Heating and Cooling (5GDHC): The label 5th generation is commonly used in the international research community. It is based on the classification of district heating system into five generations.
  • District heating 5.0: This term results from the term district heating 4.0. The classification 4.0 or 5.0 originates from the different generations of heating networks, which are distinguished in international district heating research. Here, 4th generation district heating (4GDH) networks represent modern low-temperature networks, which are operated at temperature levels of 40 - 80 °C. They have lower heat losses than third generation networks. However, since 5GDHC networks differ greatly from the fourth generation, for example in terms of network temperatures, the term "fifth generation" has become common.
  • Bidirectional low temperature networks: The term "bidirectional" refers to the two-way energy flow between the building and the heating network: Buildings can draw heat from the 5GDHC network or feed heat into the network (prosumer). "Bidirectional" does not refer to the mass flows in the network. To describe the non-directional mass flows in the network, the term undirected network has become established.
  • Ambient loop: Here, the word "ambient" refers to the network temperatures, which are close to the ambient temperature.
  • Balanced Energy Network: The term "balanced" here refers to the fact that heating and cooling loads can be partially balanced by the network, and thus the heating and cooling power supplied from the energy hub can be greatly reduced in some cases.
  • Combined heating and cooling (CHC) networks: The term "combined" emphasizes that a heating network can cover both heating and cooling needs. The term was proposed in a scientific study from 2021 for 5GDHC networks.
  • In French, 5GDHC networks are called Boucle d'eau tempérée and means "tempered water loop".
  • In Denmark, 5GDHC networks are also referred to as Termonet (Thermonet).
  • In the United States, the term Geogrid is also common.

Commercial marketing names

  • ectogridTM: The German utility company E.ON commercializes 5GDHC networks under the label ectogridTM. The focus of these systems is on the supply of heat and cold, which maximizes the balancing of heating and cooling demands and therefore leads to high system efficiencies. A smart system control is used which also helps to connect multiple districts using cloud solutions to exploit synergy effects between different districts.
  • GeoGridTM: The US company EcoSmart Solution offers a 5GDHC system with geothermal sources under the label GeoGrid.
The nPro tool has been developed especially for the planning and design of 5GDHC networks.

Less suitable terms

  • Low-temperature networks: This term is also used occasionally. However, it is not a good choice because it also includes ordinary heating networks with flow temperatures of 40 °C and above.
  • Low-exergy network (LowEx network): The term low-exergy network is not sharply defined and generally refers to low-temperature networks, not just 5GDHC networks. "Low-exergy" emphasizes that due to the low supply temperatures, the share of exergy in the delivered heat is lower than in hot networks. The term is therefore related to the term "anergy network", which expresses that the heat supplied is entirely anergy and not exergy.
  • 4th generation district heating (4GDH): Low-temperature networks are also referred to as 4th generation heating networks in accordance with the common classification of district heating networks.
  • Ultra-low temperature network (ULTDH): Although a uniform definition is missing, the term "ultra-low temperature network" (ULTDH) is mostly used to describe heat networks that can cover space heating demands directly with heat exchangers and only provide domestic hot water with decentralized heat pumps in the buildings. However, 5GDHC networks are systems in which decentralized building heat pumps must be installed for the provision of domestic hot water and space heating.


  1. Information on ectogridTM system by E.ON
  2. Information on Balanced Energy Networks on
  3. Scientific study about the terminology of modern district heating concepts: Vocabulary for the fourth generation of district heating and cooling, M. Sulzer, S. Werner, S. Mennel, M Wetter, Smart Energy, 1, 100003, 2021, DOI: 10.1016/j.segy.2021.100003
  4. Modeling and Simulation of a Heating Mini-Grid for a Block of Buildings, K. Filonenko, K. Arendt, M. Jradi, S. Andersen, C. Veje, 16th IBPSA International Conference, 2.-4. September 2019, Rome, 2019.

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