Individual System Architecture
An automated building using wireless components can be realized with different system architectures according to its individual requirements. When choosing a system for particular retrofit projects, it is important to consider the conditions onsite and the goals of automation.
A wireless decentralized automation system can serve as a basis. Thereby the wireless sensors are programmed directly onto the specific receivers (relays). This could be, for example, switches for shutter control or occupancy sensors that turn on the light depending on the presence of persons. With the application of sensors, which capture different parameters (light intensity, temperature and presence), one device can cover several functionalities and, therefore, save costs.
With wireless components connected to a central web server, building operators can bring together, visualize and control automation at a central point. Gateways can incorporate the wireless components in other systems, like BACnet or KNX. For a secure data transmission to the central control or a gateway, energy-harvesting wireless solutions offer built-in security measures for safe two-way communication in building automation. To avoid transmission errors, a checksum is appended to every data packet. This ensures the radio telegrams are not altered during transmission (integrity is safeguarded) and so prevents transmission errors. Moreover, each wireless module has a unique 32-bit identification number that cannot be changed or copied, which protects against duplication. This authentication method checks that the identity of a sensor is genuine. For applications requesting additional data security, batteryless wireless communication can be protected with enhanced security measures, such as a rolling code incremented with each telegram or AES 128 encryption algorithm.
In the Right Position
The correct positioning of the sensors and actuators is also important for a meaningful plan. The receiver devices (relays) turn on, dim or control and should–as a general rule–be positioned in the standardized installation zones. If there are no (bus) cables or empty conduits available, then planners can use decentralized wireless actuators.
Sensor positioning demands more attention. Occupancy sensors should not be placed in common areas. Temperature sensors and air-quality sensors should not be positioned at places with drafts of air, such as beside an entrance door. In temperature sensors, direct sunlight can compromise the measured data. Switches should always be positioned in the customary place. In addition, for comfort purposes, switches can be placed at office desks or used as a handheld mobile device. For all sensors, the following applies with equal measure: The sensors must be adjusted accordingly whenever the office structure changes. Wireless devices fulfill all these demands. Even with basically wired relays, wireless sensors should be built in.
Along with flexibility, wireless automation systems for HVAC and lighting offer meaningful cost advantages. In new builds, they save typically between 15 and 30 percent of installation costs with savings of as much as 70 percent in retrofit projects. The automation itself reduces the energy consumption of a building in operation from 20 to 40 percent, offering a return on investment between two and seven years.
Worthwhile Expertise
Building codes do not dictate in detail the degree of automation of a building. All the more, many automation functionalities have a positive effect on the energy balance of a building. The new-build sector can therefore significantly reduce primary energy needs and is already prepared for upcoming future tightening of savings goals. Existing buildings improve their carbon footprint and thereby the market value of the property.
As soon as facility managers gain exposure to building codes, they should familiarize themselves with building automation. Technically meaningful and user-defined installations can exploit savings potential and simultaneously minimize effort and keep costs down. Whoever establishes punctual expertise in building automation lays the founding stone for an energy-efficient and therefore high-value building–a crucial competitive advantage in the property market and, these days, because of strengthened building codes, a legal obligation.
IMAGES: EnOcean