4th generation district heating requires lower temperatures

In an R&D project, Cilla Dahlberg Larsson describes how we need to adapt the equipment in new residential buildings to be able to use 4th generation district heating, 4GDH, with significantly lower temperature levels than today’s district heating systems.

 Cilla works as a project manager at FVB in Gothenburg. She has been the project manager for the research project “Fastighetsanpassning för 4GDH” (Adapting properties for 4GDH), with Patrik Selinder, FVB, and Håkan Walletun, W2, also contributing. The project has been funded by Energiforsk’s program Futureheat.

The research report builds on an earlier project report produced by Sven Werner and Helge Averfalk at Halmstad University, “Framtida fjärrvärmeteknik” (The future of district heating technology).

“You could say that our report describes the practical dimension of how to build for 4GDH and thus be able to lower the temperature levels in the district heating systems to 50–55 °C in the supply and 20–25 °C in the return,” says Cilla.

“It shows how 4GDH will be used in new houses through modified technical solutions.

Traditional district heating requires relatively high heating needs to achieve economic profitability. Because future apartment buildings will have significantly lower heating needs, there is a risk that the market will choose different heating solutions than resource-efficient district heating.”

By investing in new technology that results in lower temperature levels, distribution losses are reduced and you get lower costs for pipes. More residual heat sources can also be used in the system, sources that currently have too low a temperature and are thus expensive and difficult to use. Even the heat from solar collectors is becoming more economical to use.

The solution is based on a district heating substation being installed in each apartment with a third pipe on the primary side to ensure sufficient temperature to the customers’ district heating substations. Each apartment owner thus becomes a district heating customer with individual metering. This involves some technical adjustments to the internal heating systems.

“For this to have an impact, it requires good dialogue with all parties involved in the construction process. It is a new idea, which means you have to plan to build this way right from the start.”

“It is important to do it right from the start and dimension all the components correctly because there are smaller margins, as the delivered temperature level is significantly lower than the current conventional, 3rd generation district heating,” says Cilla.

For more information:
Cilla Dahlberg Larsson, 031-10 60 86