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4DH gives expert advice to EU’s Energy Efficiency Directive

4DH Research puts District Heating on Global Agenda

District heating research affect European energy strategy

4DH reduces energy costs more than fossil fuels

Everything about the 2nd International Conference on Smart Energy Systems and 4DH on 27-28 September 2016 in Aalborg

New video: Smart Heating Systems save money and CO2

The Hypothesis of this project was that it is possible to convert the existing district heating grid from high temperature to low temperature. This means reducing supply/return temperatures to 50/25 in areas with low energy demand buildings and extend DH grids to areas where the existing buildings will be energy renovated over the next decades or newly built-areas with low energy demand buildings. By lowering district heating operating temperature, it is possible to utilize low-grade energy sources and renewables to provide heating. This is fundamental in the Danish objective of being 100% fossil fuel free by 2050.


Finding the optimal supply temperature in existing DH system has a key role in the implementation of low-temperature district heating. Reducing supply temperature will results in a heat loss reduction in the distribution network. It may however also result in an increase in pump power demand in the network.

The study aimed to develop a new model for applying low temperature DH concept for existing DH network by evaluating several factors simultaneously. The model was developed to find the optimal supply temperature in existing network, considering pipe network heat loss, bypass heat loss, pump power demand and return temperature all together.


Furthermore the new configuration for bypass system was evaluated in order to reduce the heat loss and inefficiencies caused by bypass in existing DH networks. The developed model was applied in district heating network in Harlev, Aarhus, to find out the optimal supply temperature for an existing system.


The main outcomes of this project were related to:
• Optimal supply temperature in existing DH network
• Proposing new configuration for bypass application in district heating system to reduce losses.
• Recommending and applying possible modification in existing DH networks (Case study area) in line with the possible modification in existing buildings which results in reduction in supply and return temperature in DH networks.
• Recommendation for reduced return temperature (EUDP project- March 2014)

 

Related articles


Conversion of existing DH systems to low temperature operations and extentions of new area of buildings
Presentation by Soma Mohammadi on the 4DH Ph.d. Fellow seminar, March 6th 2012, Aalborg University.

 

 

 

 

 

 

 

 

 



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