Precision control for intelligent buildings

KNX, the world wide open standard for building and home control is fast becoming the building automation system of choice throughout the UK with high profile projects in landmark buildings and luxury homes. The KNX international standard brings together control technology from leading manufacturers, which works together seamlessly and, as we all know, the whole is inevitably greater than the sum of the parts. The international KNX Association has partnership agreements with more than 21,000 installer companies in 70 countries: KNX has unequivocally arrived.

As the backbone of a building’s control system KNX brings together all of the technology in a building. Integrators and specifiers can choose equipment from a pool of off-the-shelf technology from a range of manufacturers, to build a unique solution for any building, be it an airport terminal building or a home for assisted living.


Electrical equipment can be controlled according to time, temperature, humidity, the presence of people etc, or any combination of these triggers. It is in presence detection that Theben AG, parent company of UK-based Timeguard Ltd, has a clear lead with its own manufactured range of products.


Presence detection


There is no official standard definition of a presence detector, but it is generally accepted that these are highly-sensitive PIRs that will detect and react to small movements such as normal hand/arm movements made while operating say a PC. It is also generally accepted that the switching behavior of presence detectors is controlled by both presence detection and light levels. So for example a person is detected in a working area, but there is enough natural sun light so that the lights can be switched off. The amount of natural light required at the workers desk would be agreed and pre-programmed into the KNX system. The system could dim lights, in conjunction with variable levels of sun light, so a constant light level is achieved.  There is even the option of a remote control for the user to make predefined changes.


It’s not just lighting though, for example HVAC systems can be controlled by KNX presence detectors along with other sensors such as thermostats. So heating can be set back if no one is in the room. Presence Detectors such as the Theben Compact Office offer accurate detection to control lighting and heating thus maintaining a comfortable environment and save energy.


Not surprisingly, the main demand for presence detectors is in office and commercial environments, including flagship projects such as Heathrow’s Terminal 5. 


Square zones


Theben’s presence detectors with their signature, patented square detection zones make planning an installation with 100% coverage easier and more economical, as fewer detectors are needed.


This makes them perfect for developers planning a single or large zoned area, depending on both occupancy and ambient light level conditions at any time. So areas by a window might not require so much artificial lighting, while adjacent areas deeper inside the building do.  Ideal candidates for KNX control are spaces where work practices or other occupancy patterns are unpredictable, such as the British Library or Leeds’ new landmark multi-occupancy building at Bridgewater Place.


Theben has estimated that, it is possible to design lighting for a large open plan office area with no gaps between detection fields and cutting the number of detectors used in some cases by almost a half, saving on both hardware and installation costs.  As one specifier so eloquently put it:  the less ‘acne’ on the ceiling of expensively designed spaces, the better, no matter how attractively-designed the devices are.


Price-performance ratios can be further boosted when specifying Theben presence detectors by using master-slave parallel connections.


The Theben Quickfix system for flush mounting in hollow ceilings reduces costs even more at the installation stage, and both initial commissioning and subsequent modifications in the ceiling mounted sensors can be made with remote control handsets. This remote control option is a major advantage as it is obviously safer and less expensive than having someone having to climb up to the sensor to make adjustments and reduces the risk of potential damage to the fabric and décor of the ceilings when devices are taken in and out, and it is the only practical solution in areas with high ceilings such as sports halls


No more blind spots


Theben’s Compact Passage detector has two detectors, facing in opposite directions and can be mounted centrally for complete coverage of passageways. Although the concept is simple, packing two sophisticated KNX-compatible detectors into a single, small and discreetly attractive casing is another Theben first.  The Compact Passage corridor detector has been a big success for Theben in the UK and the rest of Europe.


Just one of these innovative presence detectors provides complete end-to-end coverage for corridors up to 30m long and 4m wide. The old alternative, to use standard single detectors, with a number of them installed along the corridor, can now be avoided.


These detectors offer a simple solution for corridors and walkways: one device and one install for complete coverage.


Niche market


Providing control isn’t just about presence detection because Theben offer a range of products to suit many different needs, a good example of which is the KNX CO2 air quality sensor.


Even marginal increases in the levels of carbon dioxide in the air can affect concentration, as anyone who has been in a stuffy meeting room or classroom will know. However, the simple expedient of opening windows does not sit well with current thinking on energy efficiency or comfort. Far better to use the Theben KNX CO2 air quality sensor to monitor and control levels through KNX controlled HVAC equipment or automatic window actuators.


Theben’s unique KNX wall mounted sensor monitors carbon dioxide along with temperature and humidity, to enable the KNX building control system to manage air quality. This CO2 detector will be especially useful in conference and meeting rooms, classrooms, low-energy homes and conservatories. Thresholds for each of the three parameters – CO2 levels, humidity and temperature – can be managed separately.


It is widely recognised that concentration can waver when CO2 levels reach just 0.1% (1000ppm). With fresh air containing 0.35% CO2 and exhaled air carrying 4%, ambient levels in busy or closed rooms can quickly reach levels where concentration fades. Higher levels can cause illness adding to absenteeism and therefore the addition of a CO2 air quality sensor can really reap rewards.


More KNX controls


Theben is widely recognised for its high quality KNX presence detectors but Theben has a wide range of KNX building control solutions that are available to UK specifiers and integrators.


The company has a long history of innovation and is a specialist in time, light and environment control equipment, and has KNX-certified solutions for everything from lighting and heating actuators to individual room regulators and combined temperature /light sensors.

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