How district heating can be optimized
By using a more dynamic approach to system dimensioning, the district heating network can be optimized. This is what new research from FVB and RISE shows.
When dimensioning service lines, the current accepted industry practice is that the flow rate should not exceed 1 m/s or a pressure drop of 100 Pa/m. This practice is designed to guarantee supplies, but also to avoid high noise levels and achieve comfort for the customer.
“In the project, we have investigated where the practical limits are for maximum flow rates in service lines in order to optimize the district heating system,” says Kristin Åkerlund at FVB.
As part of the project, we have conducted a literature study of current industry practices for dimensioning, but also for noise problems and internal damage to service lines. To get a broader and more detailed understanding of noise and where noise arises in the district heating system, several network owners and material and service providers have given us their point of view based on their experience. In the project, RISE has also performed measurements on pipes in different materials and dimensions and two different heat retention valves.
“We have been able to determine that the current industry practice of 100 Pa/m includes a safety margin to avoid large pressure drops in the network and is not linked to the risk of noise occurring in the system,” says Kristin Åkerlund.
The measurements indicate that at 1 m/s, it is not the service lines themselves that produce noise, rather the noise comes from components in the district heating plant.
“By adapting the dimensions of the service lines to the local conditions, you get a more optimal system. The project has therefore also produced a guide for dimensioning and a digital cheat sheet as a support for designing service lines,” Kristin Åkerlund concludes.
The report “Dimensioning service lines in distribution systems (Swedish)” can be downloaded for free at energiforsk.se. The project has been funded by Energiforsk.
For more information:
Kristin Åkerlund, 026-14 16 20