Wireless: Building automation's future?
Looking around, it's safe to say that wireless communication has permeated our daily lives. Not only are cell phones used extensively, but even church steeples in New England now support cell towers. Domestic wireless communication is growing so fast that 24 million new subscribers signed up for cell phones in 2000. So why not wireless building control as well?
A wireless communications link can provide mobile computing devices, such as personal digital assistants (PDAs), complete access to facility operational data. It allows maintenance operators and facility managers — no matter where they are — to see what is happening in real time. Remote access can increase productivity and uptime in critically important operational systems.
For instance, the operational staff can be instantly alerted to events, alarms and operational data. They will be able to analyze activities or problems as they occur and can take initial actions by remote control of motors, fans, pumps and other building systems.
Moreover, wireless makes sense simply because wire pulls can be expensive, especially when retrofitting older buildings where access is limited. Low-priced wireless technology presents a more appealing and cost-effective alternative.
Despite exciting developments, the use of wireless in commercial and industrial applications will evolve gradually.
The goal is a system that will transmit over long distances and function in moving vehicles. At present, this is still the stuff of dreams. Users must segment applications and prioritize either bandwidth or distance to keep costs down.
Although IT departments, PDA users and consumers vie for more bandwidth and greater transmission distances, the wireless requirements for BAS are actually relatively simple. Except for the operator interface, BAS are typically stationary, low-bandwidth systems operating in proximity. Wireless transmission for low-bandwidth local communication has a low cost, resulting in the advent of competitive products for the type of applications required in BAS.
Wireless operator interfaces offer one of the most immediate returns for building automation. They use standard Internet protocols to send and return data. Data from the building system is centralized in an Internet server that is a communications link to wireless computing devices carried by the operating staff. Standards such as wireless application protocol (WAP) allow a mini-browser on a PDA or cell phone to connect to the Internet. This same technology enables users to monitor or control BAS.
Eventually, when cell technology with 2-megabit per second (Mbps) bandwidth is implemented, real-time video access to cameras placed in the facility will permit even higher levels of surveillance and control with mobile devices.
Sensors, controls and switches
A growing number of companies currently manufacture wireless temperature, pressure and flow sensors. Additionally, they have introduced wireless read, verify and change controls for pumps, motors, fans and variable-air-volume controls. These devices use a variety of technologies.
Because of relatively higher costs, wireless switches for lighting control have not been widely used. However, as the prices of wireless devices come down and the costs of labor and materials increase, wireless switches will become increasingly competitive. Wireless technology has also made advances in fire and security systems.