The recently-published draft Code of Practice for heat networks from the Chartered Institution of Building Services Engineers and the Combined Heat and Power Association marks yet another important milestone in the UK’s burgeoning district heating sector.
It is a clear indication that the technology is entering the mainstream and it could be argued that in establishing such a framework that details best practice, district heating is finally growing up.
Having been around in the UK since the 1970s, many would argue that it is already an old technology. These pioneering systems and many of their subsequent failures have been well documented, but the increased focus on heat network development that has taken place in recent years following the technology’s recognition by the government has heralded a new generation of systems.
With targets to increase the market share from around the current 2% of homes to around 20% by 2030, this could certainly be viewed as a new beginning – and the next target of 40% by 2050 as revolutionary.
An important aspect of the draft Code of Practice is a suggested best practice in regards to flow temperatures. This recommends that they should be kept below 80°C, which effectively levels the playing field for pre-insulated polymer pipe systems to compete with their once ubiquitous steel counterparts.
Pre-insulated steel pipe systems still have a role to play in the development of larger district heating networks, particularly where transmission and arterial systems are required and, of course, designed, installed and operated correctly.
At the distribution level – for example, a large housing estate – polymer-based pre-insulated networks can offer many advantages over their steel counterparts. The most obvious is the effective removal of corrosion.
Whether the choice is for rigid polymers such as polypropylene in straight lengths or flexible, cross-linked polyethylene in continuous lengths, the issue of thermal expansion and problem of dodging underground obstacles get a whole lot easier.
Onsite jointing becomes quick and simple, with a variety of methods available – from mechanical couplings through to electro-fusion typically being available and offering excellent levels of joint security.
It is important to note that by selecting these corrosion-free polymer-based systems, designers, installers and operators are not absolved from responsibility.
Every aspect of a network’s development still must concentrate on ensuring quality – both in terms of its ability to deliver heat and maintain its efficient operation.
The new draft Code of Practice sets out a framework under which this can happen. Jointing techniques in all types of pre-insulated pipe systems must be of primary focus, whether it is the service pipe joint or the casing – both can have a profound effect on a system’s efficiency and life expectancy.
The whole sector – from system owners and developers through to installers and operators – must all pull together and ensure that this new Code of Practice is fully embraced and seen as the go-to standard on which a successful system can be developed.
Mark Whettall is managing director at CPV