Advancing the science of wireless control
The average of 7 m of cabling associated with sensors in a building-management system quickly add to the cost and time of installing such systems. Andreas Schneider looks at the many benefits of wireless, self-powered devices.
Tougher environmental standards and soaring energy costs demand optimised concepts for the way we use our energy in buildings. This necessitates building-automation technologies that enable such concepts to be speedily and seamlessly implemented, whilst reducing operational and maintenance costs.
Self-powered wireless technology is particularly effective. In addition to saving energy, it can also greatly simplify the cabling of a building, minimise maintenance requirements and allow faster response to changes in building configuration.
EnOcean GmbH has supplied components for self-powered wireless technology for over six years. They harvest their energy from resources available in their immediate environment. Circuitry inside switches is powered by mechanical energy dissipated as the button is pressed, and thermostats are powered by small solar cells. Other components harvest energy from rotational movements, vibration or minor temperature differences. For building specifiers, contractors and installers, there are several key benefits.
• Flexibility: Many physical first-fix activities can be eliminated, co-ordination issues with other trades’ schedules reduced and last-minute changes or design constraints easily accommodated. In a lighting-upgrade project for the entrance and bar area of a Dubai hotel, the renovation was completed using self-powered wireless technology while the hotel continued operating normally. Lighting energy consumption was reduced by over 87% and overall illumination increased.
• Simplicity: Cabling topologies are greatly simplified, freeing installers to adopt a ‘radial’ point-to-point format. There is also no need for power cabling to individual units. Numerous office refits worldwide have used this technology to allow sensors or actuators to be installed on walls and non-permanent features such as room partitions, allowing office spaces to be quickly reconfigured in future without compromising the building-services infrastructure.
• Cost effective: About 10% of the cost of the entire building-automation system when first installed can be saved. For example, 4200 wireless sensors in one building alone saved the cost of over 30 km of cable installation.
These compelling advantages have led to over 100 000 buildings being successfully deployed with self-powered wireless technology. Further development of technologies and standards aim to increase adoption and advance the prospects for wireless, self-powered control in building-automation and other sectors.
Future-proof
The first generation of EnOcean technology was built using numerous discrete components. However, the introduction of a new system architecture (EnOcean Dolphin) based on a sophisticated, power-saving custom integrated circuit, unites wireless technology and programmable digital electronics in a single, ultra-compact, low-power, low-cost unit. By supporting energy-autonomous actuators, bidirectional communication with sensors, and innovative routing concepts, this platform creates the foundation for a wide variety of new products and applications to save energy, enhance comfort and security, and support efficiency-oriented initiatives such as detailed consumption metering.
The Dolphin architecture was developed to enable non-proprietary systems to match the increasing demands of many different applications. It has an intuitive operating system and software features that speed up design and maximise flexibility for independent developers of wireless modules and system applications.
Recent innovations based on the Dolphin platform include a bidirectional, self-powered room sensor to transmit measured values of temperature and humidity and remain awake to receive a message such as a new temperature set point, a time-synchronisation signal, or feedback information to present on a display for the user. This allows a room sensor to indicate, for example, if a window is open, so that the heating or air-conditioning can be adjusted accordingly.
The platform has also enabled ultra-low-power timers that enable devices such as radiator actuators to obtain their settings in cycles from a central station and draw their energy from the difference in temperature between the heating and their surroundings. In the future, through further development of EnOcean communication, it will be possible to wirelessly control a heating radiator valve.
Among OEMs currently developing products using the EnOcean platform, MK Electric has won success in lighting applications and other local-switching challenges with its Echo wireless self-powered switches. In a recent project, a highly distributed plant-control infrastructure implemented using multiple Echo switches at the Aberdeen-based oil-and-gas engineering company Acergy has saved workers walking up to 85 m to switch items of equipment on or off from a central controller in the plant room.
Product interoperability
To ensure continued, seamless cross-vendor product interoperability for EnOcean-enabled products, the EnOcean Alliance has published the first open specification for battery-free wireless sensors. Jointly devised by the members of the international consortium, the specification enables implementation of non-proprietary and cross-facility smart solutions for energy-efficient building automation.
Some 50 EnOcean equipment profiles (EEPs) in the specification define different switching functions, remote controls, sensors and combinations of sensors for temperature, brightness, motion and humidity. EEPs are also defined for devices such as dimmers and other actuators. These EEPs are unique identifiers that describe the functionality of an EnOcean-enabled device, irrespective of its manufacturer. To ensure interoperability, every manufacturer must make a binding declaration that their product meets the EnOcean Alliance specification.
The specification is a major milestone towards the worldwide implementation of flexible, wireless, low-energy systems to manage services and resources in all types of premises, from domestic homes to commercial properties, hospitals, schools and even large yachts. For building installers, contractors and specifiers, it will result in an even greater selection of components and more implementation possibilities, as a result of a growing number of products and suppliers.
Andreas Schneider is executive vice-president and founder of EnOcean GmbH.
