In addition to saving energy, lower system temperatures are a prerequisite for a cost-effective increase of the proportion of renewable energy sources in district heating systems.
The new guidebook entitled Low-Temperature District Heating Implementation Guidebook documents that existing buildings can be comfortably heated with flow temperatures from district heating plants in the range of 50-60 °C most of the year, and that return temperatures can be in the range of 25-35 °C if the heating systems in the buildings are well controlled and operated.
Seeing that European district heating systems are expected to supply approx. 950 TWh in 2050, the benefit of full implementation of low-temperature district heating can be estimated at more than EUR 14 billion annually.
Possible transition from the current heat supply (expressed with the origins of the supply) to buildings within the EU being fully decarbonised by 2050, according to the Heat Roadmap Europe cluster project. (Illustration from the new guidebook).
The new guidebook contains a number of case studies in which low temperatures have been implemented. The guidebook also describes five groups of network configurations in 14 variants for implementation of low temperatures. Finally, it contains information on distribution costs and the factors that should be considered when choosing a business model for low temperature district heating.
The new guidebook has been prepared over a period of three years by energy researchers from a number of countries. The work has been performed within the framework of the International Energy Agency’s working group on district heating and cooling. The contents are based on more than 250 scientific publications and 165 different specific measures aimed at implementing lower temperatures in buildings and district heating networks. From Denmark, DTU has contributed to the work with participation of Professor Svend Svendsen (PhD), PhD Dorte Skaarup Østergaard, researcher Michele Tunzi (PhD), and PhD student Theofanis Benakopoulos. Director Oddgeir Gudmundsson (PhD) from Danfoss has also contributed to the guidebook with Danish experiences with district heating technology, supported by funds from the Danish Energy Agency.
The new guidebook can be downloaded free of charge from https://publica.fraunhofer.de/eprints/urn_nbn_de_0011-n-6402040.pdf
A number of trials and experiences with lowering temperatures in Danish district heating systems are included as a central part of the basis for the new guidebook. (Illustration: Maryna Miliushchanka. Photo: Sven Werner).
A large number of case studies from many parts of Europe are included in the new guidebook. (Illustration: Fraunhofer IEE. Map taken from Eurostat).