Sustainability is not just about solar and wind power. Contractors should focus on the basics, and intelligent building control can facilitate big reductions in costs. EMC looks at one such solution – the KNX protocol

Rising costs, security of supply, environmental impact and sustainability, legislative targets. Whichever aspect you focus on, the issue of energy is generating news headlines like never before.

Factor in an increasingly inhospitable economic climate that some analysts suggest could soon tip over into full-scale recession, and it is easy to see why many businesses are now poring over their energy use statistics in search of potential savings.

Intelligent building control has been a hot topic among property developers, contractors and commercial facilities managers for more than half a decade, but the economic slump has put it even higher on the agenda. Consequently, there has been renewed interest in a number of technological solutions and enablers, not least, KNX.

KNX is an international network protocol for intelligent buildings. Owned and administered by the KNX Association, KNX facilitates communication between primary building systems via an open standard, enabling them to respond to users’ behaviour and requirements. By doing so, it is possible to minimise unnecessary use and reduce overall energy consumption of a home, industrial facility or commercial building.

Siemens is one of KNX’s most ardent advocates. Russell Downing, business development manager at Siemens, says this widespread acknowledgement of the technology’s energy-saving potential hasn’t arrived a moment too soon.

“A KNX control system provides building managers and owners with a highly cost-effective way of ensuring energy is conserved, facilitating financial savings and a reduction in business costs,” he says. “The concept of an energy-efficient building is not only desirable, but – for regulators, purchasers and industrial managers – it is essential.”

One of the benefits of the technology is its ease of implementation. One twisted-pair KNX cable will serve both a refurbishment or a new-build. This cable can be placed in the same containment as the power cables because of the foil insulation. By the same token, system expansion at a later date is also eminently achievable.

“There is a definite bonus in terms of future-proofing because it’s relatively straightforward to expand a system further down the line,” confirms Downing. “When considering the benefits in terms of what KNX can do, most would agree it to be a cost-effective system, and in the medium term, it easily repays the investment.”

It’s not just manufacturers who are singing the praises of KNX. An increasing number of electrical contractors and integrators are also advocating the protocol as the most accessible route to comprehensive and flexible intelligent building control.

Alan Vickery, managing director of intelligent building solutions integrator EnTech, emphasises the advantages of an open standard approach.

“The fact that some of the most trusted names in the electrical world are supplying into that protocol gives the end-user peace of mind,” he says. “The decentralised nature of the system – if one element shuts down, the rest of the system carries on – is also a major benefit, as is the long life-expectancy of KNX products.”

“I believe in it,” says Paul Davies, co-owner of Intelecs, KNX integrator for EnTech. “Not only can it reduce overall energy costs by 40%, it is also easily upgradeable and expandable, as long as you have got a bus system in there. Also, the fact that it is an open protocol means that you can mix and match equipment from different manufacturers.

“New products are coming out all the time now, and the great thing is that you are not restricted to the one company.”

While KNX can be integrated into heating, ventilating and air conditioning, security and numerous other key building systems, it is in the area of lighting where the benefits are most readily apparent. Not only can lights be dimmed or shut off altogether if a room or building is unoccupied, they can also be precisely adjusted on a zone-by-zone basis.

At the simplest level, KNX means that the unwelcome vision of an unoccupied office block that is lit throughout the night for no apparent reason can finally be consigned to the past. At a more intricate level, the protocol also allows lighting to be tailored to the requirements of various departments, even the preferences of individual users.

The average life of a modern lamp is increased by using the KNX protocol. Lighting fixtures are used more sparingly and at lower levels of output, and the KNX Association claims that lamp replacement cycles can be extended by months, if not years.

“Lighting is the key driver for this technology,” confirms Siemens’ Downing. “This is the area that will show the quickest return on investment as it’s the thing that consumes the most electricity if it is misused.”

While Siemens will continue to develop its range of KNX-compliant equipment, including the Gamma range of building management systems, Downing emphasises that the KNX protocol can only be one part of a fully realised, energy-efficient installation. A step change in employer policy and employee behaviour is required. Companies need to make a well-rounded and easily understood energy strategy the first item on their priority list.

“An average building management system requires a significant human element for optimal effective operation, even if it is correctly specified and installed,” says Downing. “Understanding the concept of intelligent buildings is vital in order to appreciate the true benefit of the available functionality and the consequences of being able to control all aspects of a building from a central point.”

Education is absolutely fundamental to successful KNX implementation. While no-one underestimates the level of commitment and investment that can be required during the early stages, the potential of this technology to bring substantial cost savings – even in the relatively short term – is ensuring that more businesses are factoring it into their new-build or refurbishment planning procedures.

Systems integrators are increasingly finding that they have to be ready to advise on, specify and install the KNX protocol in order to satisfy the requirements of the end-customer.

“KNX has crossed over into the mainstream,” concludes Vickery. “What has been for many years a slow, steady evolution is now turning into a revolution.”

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What is KNX?

  • KNX, formerly known as the European Installation Bus, is an open protocol specific to building controls
  • KNX is recognised internationally as Cenelec standard EN 50090
  • Around 120 manufacturers produce 11 000 KNX products
  • All new products are backwards-compatible
  • The system works on a simple two-pair bus cable
  • There is a maximum of 64 devices per line, 12 lines per zone and 15 zones
  • The maximum total length of a line is 1 km and the maximum distance between devices is 750 m
  • The maximum distance between device and power supply unit is 350 m
  • Minimum distance between two power supply units is 200 m on the same line