Cold district heating
The term cold district heating is composed of the terms "cold" and "district heating" and has characteristics of both, as we explain on this page. Cold district heating is also referred to as 5GDHC networks (5th generation district heating and cooling) or anergy networks.
Heat supply through cold district heating
Cold district heating describes a network-based heat supply at a very low temperature level. The network temperatures are so low that heat pumps are installed in the buildings to raise the heat to the required temperature level for the provision of space heating and domestic hot water. Current research investigates whether cold district heating networks are a solution to decarbonize ordinary conventional district heating networks and whether district heating networks can be transformed into cold district heating networks. The main problem here is that very large pipe cross-sections are required for cold district heating network and that buildings must be equipped with water-to-water heat pumps in order to achieve the flow temperatures of the respective heating systems in the buildings. Ambient sources (e.g. rivers or lakes) can serve as a heat source for cold district heating networks, which are often available in large cities and represent a uniquely large and relatively easy to exploit heat source potential. Another heat source that is widely available in large cities is waste heat from sewage water or subway shafts. Sewage water has year-round temperatures of around 12 °C and is therefore suitable for feeding cold district heating networks.
Advantages of cold district heating
The advantages of cold district heating are that, on the one hand, there are almost no distribution losses, which is a major advantage over conventional heat networks, especially in summer when heat consumption is low. In addition, cold district heating networks can provide not only heat but also cooling energy at low cost with the same network infrastructure. The waste heat fed into the network by cooling processes can be used by other buildings, for example, to provide domestic hot water. On the subpages on 5GDHC networks, a full list of advantages can be found.
Which cold district heating networks exist?
A few hundred cold district heating systems are already in operation. Project examples are described in the list of 5GDHC networks. Most projects are realized in Germany, Switzerland and Scandinavia. However, the technology of 5th generation district heating and cooling currently spreads around the globe and first projects in North America and Asia are developed as well.
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