The first Buildings Control Show organised by BSEE was a unique event. With memories of big events like EcoBuild still fresh, none of us really knew what to expect and were pleased to find ourselves at an event where visitors were as excited as us about new ideas coming to market. Equally useful was the opportunity to talk to other exhibitors about how all our products work together, because the increasing use of open protocols has now changed the way systems integrators work and the way that manufacturers think.
I’ve always been passionate about the way that open protocols like KNX mean that different manufacturers’ equipment works seamlessly together. And, while my colours as an employee of the Theben group and its main representative for its building controls in the UK are nailed to the KNX mast, what really struck home at this show was how well the different protocols work together. There are gateways between all the significant protocols now – I think Theben’s recent launch of an Opentherm/KNX gateway was the final link in the chain. Indeed, control systems for managing larger buildings are sold with a range of protocols built in – KNX, BACNet, and Modbus. You make your choice and pay your money for the enabling code.
Nevertheless, I still believe that it is KNX that ticks all the boxes as the only truly open and international bus protocol for modern, future-proof building management, and it still remains the best choice when there is an opportunity to improve building efficiency by integrating equipment from different manufacturers, as must increasingly be the case with complex building control.
Flexibility and simplicity
Increasingly KNX is chosen not just for new build and major refurbishment, but as ‘islands’ within buildings as areas are gradually updated. Rather than extend the installation building’s existing protocols, installers are opting for the flexibility and simplicity of KNX. The tables will continue to turn, and it is not KNX but its predecessors that will be the islands, although, I can see that BACNet over IP will still be preferred, for now, in particularly intensive applications where high bandwidth is an issue.
The bottom line is that re-cabling for KNX is neither complicated nor expensive, and the long term benefits quickly return the investment in change.
A single KNX bus wire will carry control data to and from devices throughout a building and the key point is that because it is a truly open protocol you can choose KNX-compatible devices from over 200 different manufacturers on merit, safe in the knowledge that they will work together.
KNX does away with the problems of isolated building management devices by ensuring that all components communicate via one common language, one that is entirely independent of any manufacturers. All bus devices are connected to the KNX cable via twisted pair, radio frequency, power line or IP/Ethernet and are able to exchange information. Bus devices can either be sensors or actuators needed for the control of building management equipment and almost all building functions can be controlled, monitored and signalled via a uniform system without the need for extra control centres.
In larger buildings there will probably be a permanent control station, but this is typically nothing more demanding on the budget than a dedicated PC or two. For smaller buildings or family homes, you can simply plug in a laptop to programme or adjust the system.
Some of you may remember EIB (European Installation Bus or Instabus), EHS (European Home systems Protocol) and BatiBUS, predecessors to KNX. The basic concept is the same, but it has grown up a bit. KNX combines the communication (or protocol) stack of EIB with the physical layers, configuration modes and application experience of BatiBUS and EHS. What this adds up to is a robust protocol built on years of experience – you know that once you’ve chosen KNX all certified compatible devices will communicate and work together. In the UK, of course, we have been rather slow to embrace this new technology, which means that now we benefit from the early integrators.
The UK is lagging behind Europe, with probably less than 10% of new projects adopting the KNX standard.
This may be because of our traditional Chinese Walls between lighting control (seen as electrical) and HVAC control (falling into the M&E camp). It may be because building control still means lighting control and DALI to many of us. But that should not be a barrier to taking advantage of KNX as there are now several KNX-DALI gateway devices available. Similarly, there are gateways with the EnOcean wireless protocol and the American Society of Heating, Refrigerating and Air-Conditioning Engineers’ BACNet.
Of course, there are lots of legacy proprietary lighting management systems already in the marketplace, which restrict end users choice of devices and usually involve them in expensive engineering contracts. Yet once installed, there is a degree of inertia because ripping them out and replacing them with a more open system represent a large initial outlay, but the rising costs of energy may soon tip the balance and create new opportunities to replace these systems once and for all.
For now, I would encourage anyone involved in a partial refurbishment to start to introduce KNX. The capital outlay is low – simply the cable. The choice of devices you can connect is ever growing and, importantly, subject to real free market competition so that manufacturers are driven to keep prices competitive and to keep innovating. You really need to look at the long-term cost of ownership before choosing which way to go on building management – and when you do that I am confident that you will agree with me that KNX has to be the way forward.
The main focus of building control in the UK projects that have employed KNX is still on lighting, which quite simply reflects the projects that integrators are doing in the marketplace. A quick look at my own sales book tells the story: while Theben offers a complete range of KNX-compatible devices including superb multi-channel room controllers, the bulk of sales are still our sophisticated presence detectors.
For example, at BBC’s Media City on Salford Quays, there are over 3000 of our square detection field Compact Office sensors maintaining the required lighting by combining natural light with the minimum of artificial light. As well as delivering energy savings in use, they proved cost effective to install. EnTech’s Project Manager for MediaCityUK said: “The Theben detector is years ahead in terms of functionality and sensor quality. The large square detection zone means that fewer sensors are required within a design, meaning less programming and cost to the project.”
Watch this space, as I can promise that Theben will continue to lead the way in the development of presence detectors in the future.
We do, of course, stand ready to support projects controlling and integrating all of a building’s systems because the next few years are going to be all about containing total cost
s. Investment in building management will deliver quicker returns against a background of rising energy costs and government incentives. The right choices will be the systems that are easy to install, easy to maintain and that deliver measurable results.