Self-powered wireless technology for green buildings
Intelligent building automation is the key to green buildings, cutting the costs of operation and purchases, as well as substantially reducing the energy consumed in buildings. In addition, solutions enabled by EnOcean wireless switches and sensors greatly simplify the cabling of a building for. At the same time they make for enhanced flexibility because no new cabling needs to be routed if alterations are made. With little effort and without damaging walls, EnOcean-enabled products can be attached where they are of optimum benefit and just as easily removed again.
No-maintenance energy at no cost
In 2001, EnOcean, headquartered in Oberhaching near Munich, developed wireless sensor modules that harvest their power from limited energy resources in their surroundings. These modules feature efficient energy converters, ultra-low-power electronic circuitry and a reliable wireless protocol. The EnOcean wireless signal is transmitted in the 868 MHz or 315 MHz frequency band, which means it can be employed in solutions worldwide. The wireless telegrams are just one millisecond long -- about one hundred times shorter than the signal of a conventional wireless switch.
To prevent transmission errors, a telegram is randomly repeated twice in the space of about 30 milliseconds. Transmitting data packets in random intervals makes the probability of collision extremely low. Installation and parallel operation of hundreds of wireless switches and sensors in restricted space is no problem at all. Statistics show that, even in a situation where you have 200 wireless sensors each sending their signals once a minute, the possibility of a data collision is only on every ten thousandth transmission.
The range of EnOcean wireless sensors is 300 meters in the open and up to 30 meters inside buildings. Each EnOcean module comes with a unique 32-bit identification number to prevent any possibility of overlap with other wireless switches.
A technology for every need
Self-powered wireless modules from EnOcean are suitable for use in many different surroundings. EnOcean OEM partners have created products for applications ranging from room thermostats with preset temperature through to maintenance-free wireless window contacts and window handles. All products enabled by EnOcean technology are entirely interoperable.
Energy for the products is produced by the pressing of a button, the turning of a handle, or from tiny solar cells. Another basic principle for harvesting energy that EnOcean is currently exploring is the difference between temperatures. Before long, for instance, we will see sensors that generate the current they need to wirelessly transmit signals from the temperature difference between the radiator and the surrounding air.
Products and systems incorporating EnOcean technology easily integrate into common building automation systems -- regardless of whether these communicate by LON, KNX, BACnet, TCP/IP or Ethernet. Sustainable energy management concepts can therefore be implemented with very little effort or outlay.
Intelligent building automation by mobile phone
An example of the successful use of EnOcean technology is the company headquarters of BSC Computer GmbH in Germany. One element of the total solution includes window handles from HOPPE based on EnOcean wireless. These are simply fitted instead of conventional window handles, with the extra benefit that they signal if a window is shut, open or tilted. The energy enabling this is generated by the closing movement -- no batteries are needed nor an external power source.
The status of all sensors is visualised by BSC BoSe software on a touch panel and by a client at each workstation. The software is also able to control all other devices, for example the lights, the entire data processing installation and other loads such as coffee makers or copiers. BSC BoSeMobile, a client for conventional mobile phones, enables all supervisory and controlling functions to be performed from a mobile phone.
BSC has also connected IP cameras to the system. In this way either single shots or complete live video streams are transmitted by UMTS/GPRS. Access to the system requires authorisation and is protected by a key.
Lighting, heating and ventilation are governed by a Siemens controller connected to EnOcean components. Building automation links to the controller by an IP gateway. All these components are controlled by the BSC software, even the alarm system.
The use of an air/heat pump with appropriate insulation together with the new controller has meant a significant cut in energy costs in the BSC building. Users can also control single rooms or whole floors through the combination of self-powered wireless and BSC software.
Flexibility made to measure
Self-powered wireless technology from EnOcean is gathering pace in building automation. Besides simplifying the cabling of a building, it allows faster response to the need for changes in how a building is internally configured. Plus these sensors do not require any kind of regular servicing. The occupants of an office have more freedom of movement and increased convenience because, if no batteries have to be replaced, they are not restricted in where they can install something. Instead it is quite conceivable that a rocker switch for sunblinds could be positioned right in front of them on their desk.
(www.electronicscomponentsworld.com, 08.09.2009)