REHAU supplies first stage of future district heating scheme

The Regional Performance Centre (RPC) Dundee at Caird Park, Dundee, is a community hub that not only provides the community with sporting facilities, but also marks the beginning of a district heating revolution for the area.

With the UK Government announcing its 2050 net-zero emissions policy, and the Scottish Government setting a 2045 net-zero target, contractors are increasingly required to prioritise sustainability when constructing new developments. It was clear the centre would need a heating system that could supply both itself and the surrounding buildings with hot water in an environmentally friendly manner.

In this situation, a district heating scheme represented an innovative solution. By using a district heating network to supply multiple homes, this development could eliminate the cost and environmental damage incurred through fossil fuel boilers in individual properties. It also demonstrates an alternative heating system for developers and local authorities to consider that adheres to the Future Homes Standard 2025, as well as the ‘net-zero’ targets.

Determining the heat requirements

Following the selection of the technology by Dundee City Council for their project, the ESB appointed polymer plumbing solution specialist REHAU to supply the required pre-insulated district heating pipework, RAUTHERMEX, which was installed between the energy centre and the rest of the development.

Now Scotland’s largest ground source heat pump (GSHP) system, the development uses three GSHPs supplied with water from a series of 120 boreholes around 200m deep, circulating hot water from the on-site energy centre. Powered by a combined heat and power (CHP) unit, these heat pumps supply the main sports hub building and smaller athletics building through the RAUTHERMEX pipework, which is connected to a low-pressure hot water and domestic heat exchanger in each building.

With the heating source and the type of pipework determined, pipe sizes needed to be specified to ensure the immediate and future heating requirements of the development would be satisfied. REHAU and Dundee City Council entered into discussions surrounding the Regional Performance Centre’s short- and long-term requirements to determine the suitable sizing of RAUTHERMEX pipework.

“We had a dialogue with Dundee City Council surrounding the total heat loads of the development,” said Kenny Boyle, Heat Networks Specialist at REHAU. “At that point, we could demonstrate that reducing the piping sizes would satisfy the design criteria and not incur any drops in pressure or velocity.”

He added, “After carrying out the same calculations based upon future expansion heat loads, we were able to present the relevant information that helped the council settle on the 160mm pipe size.”

Flexibility and speed from polymer

Due to the flexibility of its polymer material, excellent thermal performance afforded by the polyurethane rigid (PUR) foam and the speed at which connections can be made, ESB favoured the RAUTHERMEX pipework over other potential solutions. They appointed Pro-Weld to install the RAUTHERMEX pipework due to their high level of expertise and experience they have with this REHAU product.

“Because RAUTHERMEX was so flexible, we were able to bend the pipework slightly around sweeping corners, reducing the amount of elbow joints in the network and therefore the friction in the water flow,” said Gregor Ford, Project Manager at ESB. “The range of options and accessories available meant we were also able to adapt to anything that changed on site.”
“We were very happy with how quick and easy it was to install RAUTHERMEX,” said Allan Davidson of Pro-Weld. “Because we were able to install it directly into the trenches and make the connections and joints there and then on site, RAUTHERMEX was very helpful from a logistical standpoint. Thanks to the polymer pipework’s lighter weight, the installation process could be carried out more quickly and easily than a steel installation.”

Pre-insulated polymer pipework is a practical option for renewable district heating systems because it ensures minimal heat losses across the network and improves system efficiency. The lower flow temperature of the heat network is also well-suited to polymer piping as it allows for a lifespan of well over 50 years.

Changing the route

The adaptability of the polymer pipework proved to be essential midway through the project. Upon discovery of a large steel water main that could not be diverted or removed, the contractor and installer both needed to change their plans for installation. Thanks to the flexibility of the polymer pipework, they were able to install the district heating pipes below the water main.

“When we needed to reroute the pipeline at least 500mm below the water main, we had to come up with a solution to make sure the flow would not be affected,” said Mr. Ford. “Using the flexible polymer pipework and the range of components on offer, we were able to use two 45-degree elbow joints and bend the pipe under the main, meaning there was very little disturbance in the flow.”

A network in the pipeline

As sustainability becomes a growing priority in construction, the future of traditional heating systems is becoming increasingly uncertain. With that in mind, this project gives a good insight into a practical alternative solution to supplying our nation’s homes with hot water. Because of initiatives such as the net-zero policy targets and the Future Homes Standard 2025, the Dundee RPC represents a renewable, low-emissions source of energy for the community that provides a sustainable future heating supply for future developments in the area.

So far, the scheme only supplies the sports centre. However, the network has two termination points which mark the beginning of housing developments that will be part of this network. As pressure from the Government to reduce energy bills grows, centralised heating networks such as these are becoming a more viable option for providing environmentally friendly and sustainable heating for communities. Furthermore, by reducing the installation, operation and maintenance costs of individual boilers in homes, these communities can also enjoy lower-cost energy bills.

“As a supplier of pipework solutions, we at REHAU are aware of our important responsibility to create innovative systems that make for a sustainable future for our communities,” said Steve Richmond, Head of Marketing & Technical at REHAU Building Solutions’ division. “Our pre-insulated district heating piping ranges, RAUVITHERM and RAUTHERMEX, provide the thermal performance and durability that is required for sustainable, renewable district heating networks.”