New possibilities for ultra-low temperature district heating in corporate district heating networks


Olga Macias, researcher in the field of energy efficiency in buildings in Tecnalia, explains the intervention developed by the RELaTED project in the demonstration site of Iurreta (Spain), in order to test the possibilities of the ultra-low temperature district heating systems in a corporate building complex.

Tecnalia coordinates the RELaTED project which aims to develop an innovative concept of desentralized ultra-low temperature district heating networks. This new concept will be tested in four demonstrations sites, in Denmark, Serbia, Estonia and Spain.

The Spanish project is located in Iurreta, in the North of Spain. This site is owned by the Department of Security of the Basque Goverment. The based consists on a total of thirteen buildings with different architectonic design and use profiles including administrative buildings, sport facilities, work houses and other constructions for residential use.

In Iurreta there is a district heating network which supplies energy for heating and domestic hot water services to the buildings. Heat is produced by two condensing boilers with a total capacity of 650 kilowats. The system is design for operating at 80 degrees.

On the based in this scenario, the intervention proposed in the frame of the RELaTED project aims to evolve to an ultra-low temperature district heating system where the renewable and waste heat sources could also take part.

To achieve this principal goal proposed interventions include:

  • The adaptation of the system facilities to operate at lower temperatures.
  • The connection of reversible heat pumps to the ultra-low temperature networks that will allow to rise the thermal level where existing terminal units provided higher temperatures.
  • The incorporation of solar energy as an additional energy source in the district.
  • Enable the installation for using the reminding heat arising from heat pumps during summer season.

This new ultra-low temperature district heating is expected to be operational in 2021.

Watch the video here