Skip to content

Perspective

District energy

District heating

Modern district heating pipe systems – the most efficient way to save energy

Total cost of ownership is crucial for future district heating projects.

Design of and choice of system for district heating networks have a major influence on performance in terms of energy efficiency, CO2 emissions and operating costs.

Financial results and environmental impact are influenced by the piping system

The pipe systems for transmission and distribution of district heating are capital goods for society and the district heating company. The pipe system is a way to  provide customers with heat and by extension, comfort and convenience. The functionality of the district heating  network has a major influence on how the district heating company performs in relation to energy efficiency, CO2 emissions and operating and maintenance costs.

The technical life span for today’s pre-insulated pipe systems is over 30 years. Therefore, it becomes important to review and optimize the long term Total Cost of Ownership (TCO) and thereby ensure the functionality and improve the energy efficiency of the pipe systems and the district heating operations over time. In that way, a modern pipe system safeguards the considerable investments related to transmission and distribution of
district heating.

Total cost of ownership is the key to choosing an optimal pipe system

The long technical service life of a pipe system means that choosing a high quality solution far outweighs the initial higher cost. Calculations, tests and experience prove that the major part of the TCO stems from heat losses from the pipe systems. Thus, minimizing heat loss during the entire operating period of the system will significantly improve efficiency and thereby lower  he operating costs of the network. This is also illustrated by the example  from Hillerød in Denmark below.

Low Total Cost of Ownership in the City of Hillerød

The TCO was applied in the selection of the pre-insulated pipe system installed in the Danish city of Hillerød.

Project details:

  • 14 km of trench primarily in DN80 – DN150
  • Operating conditions, Tf/Tr:/Ta 80/40/8 °C
  • Energy costs: 27 EUR/MWh
  • Required system: TwinPipe

The different solutions considered by LOGSTOR:

  • TwinPipe insulation series 1, 2 or 3

The chosen solution:
The basis for evaluation of the incoming tenders included, in addition to the direct capital costs, operating costs related to the heat loss from the  transmission systemduring a 30-year period, which makes up for approx. 40 per cent of the total capital costs. The technical value of the proposed products and solutions was also included in the evaluation.

The project owner decided to install a pipe system based on TwinPipes in insulation series 2 offered by LOGSTOR. This system provided the lowest TCO taking into consideration the investment cost and the heat loss cost over 30 years.

Benefits:
An energy efficient system with approx. 20 per cent energy savings in comparison to a solution based on Twin pipe series 1 and +40 per cent savings in heat loss in comparison to a traditional pair of single pipes in insulation series 2.

Download our publication on district energy

This article is part of our publication ‘District Energy’

Download now

The key issues in optimization of a pipe system

Total Costs of Ownership is influenced by several parameters:

The design of the pipe system must be based on the real operating assumptions in a way that secure the minimum expected life span of more than 30 years. This is secured by using the guidelines in the European standard EN 13941 resulting in simplifying the system and reducing the number of
compensators, U-loops etc.

The components must be chosen so thatthey fulfill the functional requirements for the pipe system. This goes for the pipes, T’ees, valves etc. but especially for the jointing system, where the lifespan relies not only on the product itself but also on a proper installation.

The greatest contributor to the TCO is theheat loss from the pipe system. Therefore, it is essential to choose pipe systems with the optimal insulation properties. In addition, heat loss can be reduced by choosing TwinPipe systems instead of a single pipe system, using higher insulation thickness and choosing pipe systems with a diffusion barrier between the outer PE casing and the PUR foam. The diffusion barrier secures that the initial low heat loss remains unchanged during the life span.

In order to monitor the pipe system continuously over its lifespan, the system should  be designed with a surveillance system that can detect at any time if there is a defect in the system and moisture is coming into the foam. If this happens, an alarm will be given immediately and repair can be arranged in good time. This ensures the expected long lifespan.

You should consider reading

District energy
District heating

publications

Power-to-x

+15

Green hydrogen is Danish hydrogen

19 September 2023
Get a full overview on how hydrogen can produce green fuels for transport and industry, create value for electricity supply and the electricity grid, and deliver heat for district heating - provided the input is green energy.

publications

Buildings

+12

Energy renovation of buildings

1 June 2022
How to realise the untapped potential of the built environment with energy renovation of buildings.

publications

CHP

+10

District Energy

1 October 2021
Green heating and cooling for urban areas

publications

Wind energy

+23

India and Denmark: Energy – a strategic green partnership with global potential

10 February 2023
How one of the world’s largest countries and one of the smallest join forces to create a new era of just, green transition. India and Denmark's Green Strategic Partnership paves the way for green growth and new business opportunities. Explore green energy solutions and start the journey today.

News

Urban planning and development

+12

Aalborg prepares to host international conference on sustainable cities

10 May 2024
In October, over 1,000 politicians and civil servants from across Europe will gather in Aalborg to discuss how European municipalities can best support the green and sustainable transition.