Research heats a new district

In the Swedish city Lund, Kraftringen is building one of the world largest low-temperature systems for district heating. Residual heat from the MAX IV research facility will supply all of the new Brunnshög district with heat. FVB has designed parts of the low-temperature system, which has a supply temperature of 65 degrees Celsius.

There is currently feverish activity in Brunnshög. A new district is being built here where 40,000 people will live and work. Homes, hotels, and offices must be built with high requirements on energy efficiency. MAX IV is also located in this area, which is a laboratory for accelerator physics and research using synchrotron light. The expansion of the facility will be complete in 2026. In the same area, the international research facility ESS is also being built, which will be used for a number of scientific disciplines, such as materials science, structural chemistry, and geophysics.

“MAX IV is already built and supplies residual heat to Kraftringen’s district heating network and low temperature district heating network. ESS will also produce large amounts of residual heat. Lund was selected by ESS partly due to the expanded district heating system that can take advantage of such large amounts of residual heat,” says Anders Jirden, project engineer at Kraftringen, who continues:

“The low temperature district heating system is being created in competition with other energy solutions.”

Lund Municipality sees Brunnshög as a showcase for cutting-edge research and sustainable Swedish urban construction. There is a goal for the district to be self-sufficient in terms of energy. In addition, at least two-thirds of all transport must be on foot, by bike, or by public transportation. Kraftringen is responsible for the low-temperature district heating expansion, but also investments in charging infrastructure for electric vehicles and expansion of solar cells.

The level of innovation in the area is high, which is not only evident in the research facilities but also in district heating, where the low-temperature system is included in an EU project.

“So far, it has been difficult to achieve profitability in areas with low-energy houses, but we are testing a number of new solutions in our low-temperature district heating project – both technical solutions and business model innovations. In theory, this can be a profitable business, now we have to evaluate how it will be in practice,” says Anders Jirden.

Among the innovative features, it is particularly worth noting that plastic carrier pipes are being used instead of steel. This is possible because the temperatures are significantly lower than in a conventional district heating system.

“Laying pipes is one of the major expense items, but with plastic pipes, the pipe laying is made easier with less excavated mass. This is a price-reducing factor,” says Anders Jirden.

However, expanding in the area is not exactly easy.

“We are expanding in the middle of a development area but where the primary customers and production have been separated by land that has not yet been developed,” explains Anders Jirden.

The infrastructure in the ground is also very crowded. Lund Municipality’s high sustainability goals for the district mean that it must be a space-efficient, green district that does not promote car driving. This is done through narrower car roads, more trees, and small street-facing green spaces. With many different types of lines underground, such as low-temperature district heating, district cooling, water and sewer lines, garbage suction lines, and electricity and fiber, it gets very crowded under the streets.

Paving the way for Europe

“But at the same time, it is an extremely exciting project and we have seen a major international interest in the low temperature system. If reality lines up with our theory that the new plastic pipes are much easier – and thus cheaper – to lay in the ground, it paves the way for many projects around Europe,” says Anders Jirden.

“For FVB, this is once again an opportunity to contribute to a more sustainable energy solution. This time, it is the staff from our newly established office in Malmö who have been entrusted with planning a low temperature system where energy that would otherwise be wasted can be used as a source of home heating,” says Lennart Larsson, Office Manager for FVB in Malmö and Gothenburg.
Zahir Ismail is one of FVB’s consultants working on the project and he thinks it is inspiring to work with new technology.

“The technology for laying plastic pipes is somewhat different from conventional district heating technology, and it is exciting to get to work with different technology solutions,” says Zahir Ismail.

When it comes to district heating, Sweden takes advantage of more industrial residual heat than any other country. With ever more energy-efficient buildings, it can also be economical to take advantage of relatively low-temperature residual heat, which is now being done in Lund.

“FVB has extensive experience working with residual heat in various processes and thus contributes to long-term and sustainable solutions for reducing the need for primary energy. Participating in the Brunnshög project feels like a natural and interesting step, where we make use of residual heat with lower temperatures,” Lennart Larsson concludes.

FACTS

• Brunnshög is a new district in northeast Lund. The laboratory MAX IV is based here, and the research facility ESS is being built in the same area.
• The facilities will produce a large amount of residual heat, which will be used in both Kraftringen’s traditional high temperature district heating network and the new low temperature district heating network in Brunnshög.
• The world’s biggest low temperature system is currently being built here, with a supply of 65 degrees Celsius and a return temperature of 35 degrees Celsius.
• In September 2019, the first customers were connected to the low temperature district heating network.

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