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Improving performance on renewable heating systems


Steve Richmond, head of marketing & technical at Rehau Building Solutions, discusses the importance of opting for high-efficiency pipework in order to maximise carbon savings on new heating project


Increasing system efficiency


In both use cases, the function of the pipework is to limit heat losses between the heat source and the target destination. The higher the temperature of the heat source, the greater potential for heat losses. Heat losses also increase over longer pipe runs, which can be multiple kilometres long on larger district heating networks. For this reason, it follows that specifying more


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s the Government’s target of achieving Net Zero by 2050 edges ever closer, the nation is beginning to evaluate the role


that technology can play in driving down carbon emissions. Within this, three forms have been touted as the primary solutions to decarbonising the UK’s heating – hydrogen, district heating networks and heat pumps. At present, hydrogen remains in its R&D phase,


rendering it more of a long-term potential solution. However, with the Future Homes Standard set to ban gas boilers in new builds from 2025, the onus falls upon the latter two technologies to make an immediate impact in the meantime.


Low-carbon technologies


Fortunately, the importance of both heat networks and heat pumps has been recognised by recent Government funding, with initiatives such as the Green Heat Network Fund (GHNF) and Boiler Upgrade Scheme (BUS) aiming to drive the uptake of both. Through funding both district heating networks and heat pumps, this provides an all-encompassing approach to decarbonisation – with both commercial buildings, larger communities and individual homeowners able to access grants for low-carbon


Steve Richmond, head of marketing & technical, Rehau Building Solutions


thermally efficient pipework is crucial to achieving greater efficiency building a heat network. For a client or operator of a district heating network, reducing heat losses increases the overall energy savings and hence reduces carbon emissions. As the nation transitions from 3rd generation to 4th generation heat networks, the usage of polymer district heating pipe is increasing as it is well suited to the 4th generation temperatures and pressures specified. Rehau’s Rauthermex pipe has a lambda value of 0.0199W/mK, which combined with its flexibility and long coils, makes it suitable for new heat networks. It is important to be aware that it’s a combination of the lambda value of the foam and the foam thickness itself which results in the actual heat losses per pipe size. For larger diameters above 160mm, the lambda


heating technology. This is crucial to achieving Net Zero, as there will not prove to be a one-size-fits-all approach in this transition.


Pre-insulated pipework


Despite the differences between these technologies, it should be noted that one solution is key to transporting renewable heat underground – pre- insulated pipework. In the case of district heating, underground pre-insulated pipework is used to distribute heat from a centralised heat source to all of buildings within the network. For the latter, flexible pre-insulated pipework is also used for remote heat pump installations, where the heat pump cannot be installed next to the property itself. Instead, the heat pump is installed a short distance away from the building, with pre-insulated pipework used to carry heat between the two.


value of REHAU’s PP-R district heating pipework has recently been improved to 0.023W/mK – a significant decrease over the previous generation. For an example length of 250m, the improved pipework achieves a 24% reduction in heat losses at 70/40°C flow and return temperatures compared to its predecessor.


Closing thoughts


As the nation looks to incorporate low-carbon technologies into its Net Zero strategy, it is important to consider the products that allow these systems to function effectively. Within this, it is possible to identify areas where efficiency gains can be made, in the interest of increasing significant carbon savings in the long term. Only through such a granular approach will achieving the world-leading targets set out by the Government be possible. As heat network and heat pump installations will form a large proportion of the decarbonisation efforts, there is significant scope for major carbon savings in this area, should a more detail-oriented approach to system efficiency be taken for each.


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