Is the UK missing a trick when it comes to specifying the pipe work associated with district heating schemes?
There is growing evidence that the use of pre-insulated “plastic” piping offers significant advantages over steel piping when taking heat loss and overall system life cycle cost into account.
Numerous research projects have highlighted the advantages of such products – the plastic system can reduce heat loss potential over steel piping. The effect is the ability to reduce boiler source temperature (and enhance efficiency) and allow for more extended replacement schedules because plastic networks do not suffer from the same corrosive limitations as steel.
This creates a number of benefits for scheme owners and operators – improved overall energy efficiency, lower long-term system life cycle costs and extended operational periods between pipe replacements.
Steel and hot water do not make comfortable bedfellows but with the superior flow characteristic of plastics resulting in the use of smaller pipes and improved heat loss performance, source temperatures can be reduced to the point where plastic networks are now a viable alternative to the conventional rigid steel pipework. In addition, they also have greater flexibility in site storage, laying and connecting.
As we are aware, most district heating schemes in the UK use steel pipework, but this inevitably means that city centre schemes need to be maintained, repaired and replaced due to corrosion and the corresponding risk of leakage.
So where can such flexible pipe systems add value? Certainly, in many city-wide schemes with district heating mains, such as Sheffield, Leicester and Nottingham, a sound business case can be made for the inclusion of plastic for secondary systems, based on network design, ease of installation and whole life cycle costs.
Any reluctance is as much to do with historic attitudes to materials usage – but the opening up of the DHS ownership and management market looks set to bring with it a more open attitude to plastic based on proven cost advantages, ease of installation, low maintenance, eco benefits and enhanced ROI when replacement schedules are taken into account.
Indeed, the emergence of energy service companies provides an apt moment to take stock of how we intend optimising the value of district heating schemes in the future.
Moreover, scheme owners owe it to the public to provide the most cost effective service available, for example in social housing properties where utility cost is key for users, or in high profile publicly-funded developments where ROI, energy efficiency and environmental benefits are key considerations.
Sandy Fairley is sales director at Flexenergy