Intelligent automation is the key to a major reduction of the energy con-sumed by a building and the whole operation of it. The use of self-powered wireless switches and wireless sensors not only very much simplifies the cabling needed in a building. It also enables flexible room arrangement, be-cause when almost inevitable changes are required, no recabling is neces-sary. EnOcean delivers innovative basic technology for the purpose. It needs no batteries, meaning that it can operate entirely without maintenance.

When you think about it, architects and planners of building services and systems almost need to be clairvoyants. Because when something new is being built, its ultimate use is seldom finalized right down to the last detail. It is very often the case that a tenant or purchaser wants subsequent changes in room arrangement – extra conference rooms if they are commercial premises or repositioning of the living room door in a chic new villa. Even what you might think were the simplest things, like altering the side on which a door hinges, attaching more sunblinds or climate control in individual rooms, can often take quite a lot of additional planning and installation effort. In all these cases the cabling of the building will usually have to be altered, resulting in delays until the new cabling is routed. Freshly plastered brickwork may have to be broken up, or ready dry walls opened for the purpose. This is naturally followed by all the inconvenience of filling, finishing and painting over. And it also means considerable more expense because the work is not likely to have been calculated in the bill of quantities.

Things would be so simple if you could forget all about the conventional cabling of light switches, shutter controls and room thermostats. The ideal solution is there in wireless technology, switches and sensors that need no cabling. Instead you simply attach them straight to the wall where you want them after the rooms are ready. It does not matter whether a door will open to the left or the right, inwards or outwards. Nor is the subsequent addition of room dividers a problem. The switches needed for the newly created rooms require no new cabling. This also applies to conference rooms with glass walls, because the sensors can also be affixed to a smooth surface. And even mobile dividing walls are possible, but still with all the convenience for switching and controlling functions that is otherwise required.

Most of the wireless systems available on the market are not without their drawbacks however. Wireless switches and sensors normally need batteries, which have to be replaced in good time to prevent a service outage, and that means a sizeable logistic chore in commercial premises.

And if wireless sensors have a battery compartment that naturally adds to their installed depth. And where you have multiple wireless solutions in relatively tight confines, there is a limit to how many actuators can be expected to work reliably at the same time.

Self-powered wireless sensors from EnOcean

Since 2001 EnOcean, headquartered in Oberhaching near Munich, has been developing revolutionary wireless sensor modules that obtain their current from the energy of their surroundings. Using power-saving electronic circuitry and an extremely short wireless telegram, EnOcean was already able to offer the first light switch in 2003 that generates its energy solely through finger pressure. The signal subsequently sent wirelessly in the 868 MHz frequency band lasts for less than a millisecond, making it about one hundred times shorter than the signal of a conventional wireless switch. For greater transmission security the data telegram is repeated twice, randomly controlled, within about 30 ms. Working by these basic principles, hundreds of wireless switches and sensors can easily be installed in very tight confines to operate in parallel, because statistics show that even 200 wireless sensors transmitting once every minute could only result in a data collision at every ten thousandth transmission.

Wireless modules from EnOcean are compact and low-profile to fit smoothly into available ranges of switches. The EnOcean Easyfit universal switch insert measures only 55 by 55 millimeters together with a single or double rocker, for instance, and is thus compatible with a large selection of frames from Berker, Gira, Jung and Merten, for example. Depending on the particular application, the wireless switch can also be screwed or adhered to a cabinet or door frame. Even when planning glass dividing walls an architect no longer has to dispense with the usual light switches and shutter switches next to a door or passage. Here switch design is also very flexible with a selection of high-grade, glass and stone frames from PEHA, for example.

Room thermostats, window contacts and more

In addition to its self-powered wireless sensors, EnOcean has also developed power-saving wireless modules for numerous other applications. They obtain their energy from a tiny solar cell with an area of 13 x 35 millimeters for instance, or by the operation of a tow rope. The spectrum of solutions created by industrial partners ranges from room thermostats with temperature presetting through maintenance-free wireless window contacts to switches for roller shutters in car workshops. In the meantime EnOcean technology has even found its way into window handles from HOPPE – these draw their energy quite inconspicuously by turning of the handle and in this way can signal to an alarm system that a window is still open, for instance, or to a climate control system that it should cut back on heating or turn off the air-conditioning to save energy.

Another basic principle for harvesting energy that EnOcean is currently exploring is the difference between temperatures. Before long, for example, there will be sensors to detect and wirelessly transmit the heating energy given off by a radiator that can generate the current they need from the temperature difference between the radiator and the surrounding air. Field trials have shown that this will work at temperature differences of just four Kelvin – so a wireless telegram can be generated once a second.

From flush actuator to intelligent building automation

EnOcean wireless sensors have a range of up to 300 meters in the open or 30 meters through walls and ceilings inside buildings. For reception of the EnOcean data telegrams in simple installations there are single- or dual-channel switching actuators or lighting dimmers that can be housed in a conventional installation box. Compact shutter actuators for direct attachment on the actuating means are available. Receiver modules have also been developed for DIN rail fitting in a multiple actuator or use in an intelligent automation solution. In the meantime the likes of ABB Gebäudetechnik, Beckhoff, Siemens, Thermokon, Wago and Wieland offer EnOcean technology in their solutions for flexible building automation. For special purposes EnOcean has also developed bidirectional receiver modules to enhance wireless range in larger buildings or to report back switching operations in safety-relevant applications.

Nothing is inconceivable – these self-powered sensors have established themselves on a broad front. Architects and building planners can let their creativity loose. Aqualisa for example offers a wireless remote control for showers to modernize buildings in regions with an antiquated water supply network. Its digitally controlled "Powershower" activates a local pump to increase water pressure when water is actually needed in the bathroom. Creating more flexibility in a building, there are self-powered handheld transmitters from Omnio or PEHA – these can remotely control electric sunblinds on a verandah, media installations and garage doors while seated in a car. Funktechnik has even marketed an office chair with an integrated presence detector that can be integrated into workplace control systems.

Technology tried and tested

Today there are more than 50 manufacturers offering industrial products with EnO-cean sensors for building infrastructure. The revolutionary technology can be found in numerous large commercial properties. Extensive wireless sensor technology went into "aviva Munich", the new home of Bosch und Siemens Hausgeräte, in 2003. This office building, designed according to feng shui principles, is notable for its flexible space configuration, made possible by EnOcean-based wireless switches and room operating devices with temperature sensors. A current example is that of SAP Germany, which in early 2007 moved into two new building complexes offering more than 45,000 sqm of floor space at its headquarters in Walldorf. Here EnOcean technology, networked with the building automation, serves for flexible individual control of sunshades and workplace lighting.

EnOcean technology is also much in demand in building rehabilitation, as in the case of truck manufacturer MAN. Since 2005, at its approximately one million sqm factory site near Munich, old office buildings have been continuously rehabilitated from the brickwork up, and fitted with self-powered sensors from EnOcean. Festo banks on EnOcean for rehabilitation and new buildings: the leading world producer of pneumatic and electric propulsion engineering for industrial and process automation emphasizes innovation and corporate design not only in its own products. Building technology follows the same rules, and Festo consequently chose a switch design from Gira with aluminium-coloured rockers and glass frame in the company's own special “caerul” colour. In 2005 a manufacturing sector was converted into an open-plan office structure. EnOcean Easyfit wireless switches of typical Festo design and colour were used for the offices and conference rooms with their glass dividing walls – they were simply adhered to the glass next to the doors.