Power consumed by heating, air-conditioning and lighting is increasingly a focus in commercial real estate too. Intelligent building automation has consequently become an essential component of effective energy economy. Interesting in this context is the use of wireless switches and wireless sensors, resulting in dramatic simplification of the cabling needed for a building. The full benefit of wireless technology makes itself felt when room arrangements have to be altered at a later date, or if a flexible system of dividing walls is set up in the first place. EnOcean delivers innovative basic technology for the purpose. It needs no batteries, meaning that it can operate entirely without maintenance.

When a company moves into new premises, it can mean a lot of stress and strain for the facility manager. Actually the structure for use of the facility and how rooms are arranged should be finalized long before the moving-in date. Because all the cabling of light switches, shutter switches and temperature sensors for heating and ventilation control has to be properly integrated in building automation. Everything would be much simpler, of course, if you could do away with all these cables in the first place. The ideal solution is wireless technology. The switches and sensors need not be cabled. Instead you simply attach them straight to the wall where you want them after the rooms are ready. Then you no longer require all the installation boxes either. It does not matter whether a door will open to the left or the right, inwards or outwards, whether the user wants to control shutters from the window or next to the door, or whether a thermostat has to be moved out of the way of office furniture.

Added to this, in big companies you find an almost continuous change of departmental and personnel structures. As a rule, even a few weeks before a company moves in, there may consequently be requests to alter the room arrangement. That means routing new cables, breaking up freshly plastered brickwork, or opening ready dry walls. This is naturally followed by all the dirt and inconvenience of filling, finishing and painting over. Plus, you need people for the job who work on an unscheduled and more expensive day-by-day basis.

Later you find the same repeated need for alterations of course – project or sales teams are newly composed, whole departments must relocate, or an open-plan office may require an extra conference room with glass walls. Wireless technology saves time-consuming cabling and rewiring in all these cases. 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 that are available are nevertheless not without their drawbacks. 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 for the facility manager from time to time. And if wireless sensors have a battery compartment that naturally adds to their installed depth. Then there is the risk of degraded operating reliability in wireless installations of a larger scale within somewhat tight confines.

Maintenance-free wireless sensors without batteries

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.

Window handle with wireless transmitter or temperature sensor with solar cell

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 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.

Interface with 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.

For large office and administration blocks, clinics and senior citizens' homes as well as for industrial use, EnOcean has developed wireless receivers that interface with very different, intelligent automation solutions. The spectrum ranges from EIB/LON gateways through to wireless adapters with an RS232, RS485, USB or Ethernet interface. In the meantime the likes of ABB Gebäudetechnik, Beckhoff, Siemens, Thermokon, Wago and Wieland offer EnOcean wireless receivers for their automation systems. 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.

Self-powered sensors from EnOcean have established themselves on a broad front. Aqualisa is one example. This company developed 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.

Wireless technology already well tried and tested

Today there are more than 50 manufacturers offering industrial products with EnOcean 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.

Summary

For a facility manager self-powered wireless technology from EnOcean not only means simplified cabling of a building. It also enables them to respond faster to frequent requirements for rearrangements within a building. Plus, the sensors do away with any need for regular maintenance. At the same time this means more freedom and convenience for the users of an office, because if there are no batteries to be replaced, switches no longer have to be installed at a prescribed location. Instead it is quite conceivable that someone might place the switch for the blinds directly on the desk in front of them.