by Paul Ehrlich, P.E.
Imagine what your next project would be like if all you had to do was set and mount the equipment and the controls installed themselves. What if you could diagnose a service problem right from your vehicle? It may sound like science fiction today, but with the use of new wireless technologies this may all be possible sooner than you expect!
There is a strong push today to deliver intelligence to smaller buildings, not just large ones. Intelligent control systems have the potential to dramatically improve occupant productivity, while reducing operating and energy costs. One of the most exciting new technologies that will enable us to deliver truly intelligent buildings is wireless communications.
Wireless has already had a dramatic impact on our businesses — and lives. Consider our cell phones, laptop computers, and handheld devices. But this is just the beginning. Radical changes are coming that will significantly impact how we install and service controls in commercial buildings.
Two broad areas where we will see wireless used in buildings are 1) for remote communications and 2) in control communications. Let's take a closer look at each.
Ideally we want to be able to connect to a remote building to troubleshoot a problem or to be notified when something is wrong. Remote communications allow us to provide customer service quickly, efficiently, and cost-effectively. Wireless communications are easily installed and often provide a cost-effective solution to achieve this connection.
There are several strong, existing technologies for remote communications that are easy to install. Both dial-up communications using a phone modem and the newer high-speed network or Internet connections offer easy remote connections. However, both of these options require significant coordination with the building owner as well as monthly connection fees. Using a wireless connection requires less coordination and can be a viable option for many projects.
The type of wireless connection required to remotely communicate with a building is called a metropolitan wireless network. Metropolitan networks provide the broadest coverage and allow for wireless communications over an entire city or region. Your cell phone is an example of a wireless metropolitan network. As you drive, your cell phone automatically moves from cell to cell — hopefully keeping you connected!
While the primary application today for metropolitan-networks is voice communication, there is an increasing-amount of data communication going over these networks. For example you can purchase handheld devices that combine voice with E-mail and Web browsing.
Metropolitan networks can be applied to buildings, providing a good alternative over wired methods. Unfortunately, there are several serious challenges with using wireless technology for monitoring buildings. These include:
Multiple standards for data communications. Today's wireless providers use a variety of frequencies and technologies making it difficult to have a uniform product that can be applied to any building.
Spotty coverage. The coverage for wireless data networks is not typically as broad as for voice coverage. It is unusual for buildings outside of a major metropolitan area to have any type of wireless data coverage.
Lack of uniform pricing and service. Each provider deals with pricing of wireless data service differently. Most do not have a good model for building monitoring.
These challenges are likely to be solved over the next few years, as new wireless data networks are announced. In the meantime, there are some wireless monitoring products on the market today, including those from Notifact and Profile Systems.
Building Control Communications
Installing wiring for control sensors, controllers, and automation within a building is an expensive and risky task. In most projects the cost of communications wiring accounts for 20 to 40% of the project cost and an even higher percentage of the project variability. Being able to reduce or eliminate this wiring offers the potential to dramatically change the cost of delivering intelligent buildings.
An internal antenna, used as part of a Wireless Local Area Network.
Wireless technology has even been applied to make vending machine purchases.
For Retrofit Applications
Wiring costs to retrofit existing buildings can be exorbitant. In the best-case scenario there is the cost of dealing with installation of hundreds of feet of cable and often conduit. In other cases this may include boring through walls or installing in occupied spaces. In the worst scenario we need to deal with asbestos, historic paneling, or other delicate situations. The cost of doing this type of retrofit is expensive — often to the point of making the project infeasible.
For New Construction
In new construction, the cost of running communications wiring is significantly lower than in retrofit. Yet for a typical control system, the communications and sensor wiring accounts for a high percentage of the project cost. Reducing or eliminating this cost can significantly improve price competitiveness and profitability.
Existing and Future Technologies
So how do we eliminate the wiring in the building? There are several existing technologies available, and others on the horizon. We can divide these into three major categories: Local Area Networks, Pointto-Point, and Mesh Networks. Selecting the appropriate one for the application depends on the building's information requirements, distance issues, and cost factors.
Local Area Networks
Chances are you may already be using a wireless local area network (WLAN). These are provided in most new laptop computers and in other devices such as personal digital assistants (PDAs). WLANs use industry standards, which result in low cost and ready availability. These are often referred to as WiFi or 802.11 networks. They are fast, inexpensive, easy to install, and easy to use. However, the communications can only travel a short distance. Also, fairly robust devices are required, which tend to use a lot of power.
While a good choice for a laptop computer or PDA that a technician can carry through a building, this technology may not be suitable for an application such as a lower-cost wireless room sensor that needs to run on a single set of batteries for three to five years.
Point-to-point wireless communications allow one or two-way communications between two devices. Simple examples are your garage door opener, or the remote that locks your car doors. These devices can be inexpensive, work over fairly long distances, and operate with batteries. However, they tend to be proprietary and you need to consider if the amount of data throughput would be sufficient to meet the application's needs. There are a number of devices on the market today for use in buildings that use this technology. Suppliers include Honeywell, Point Six, Kele, Totaline, and others.
Mesh networking is a newer technology that was first used in military applications. With a mesh network, each device is able to act as a radio receiver, transmitter, or repeater. Special software in each device allows for creation of a network where the optimal communications path is established in real time.
Using a mesh network within a building allows for ready communications for a wide variety of low-cost devices. For example, the mesh network could be readily used for wireless sensors, control devices, light switches, light sensors, and fixtures.
A series of standards is being created for mesh networking. The Institute of Electrical and Electronics Engineers (IEEE) approved the basic standards for radio and data communications in 2003 (IEEE Standard 802.15.4). A new organization named Zigbee (www.zigbee.org) is working to define the networking standards.
A number of new companies have formed to provide this technology, and semiconductor companies are starting to produce the mesh networking chips. The industry expects this technology to provide a costeffective solution for sensors and controllers for both retrofit and new construction projects in the next two to four years. Some mesh networking products are already on the market from suppliers such as Kiyon, Ember, Millennial, and Dust.
For now, start to explore the existing point-to-point devices. These may make sense for existing building projects where running wires is prohibitively expensive.
Over the next few years, keep your eyes open as new products are introduced. These will start rolling out for selected applications and will gradually make their way into mainstream projects. Many in the industry expect to see future projects dominated by devices that will allow for ready remote operation of buildings from anywhere.
Paul Ehrlich, P.E., is owner of the Building Intelligence Group, St. Paul, MN, which serves building system suppliers, owners, and managers. He was previously with Trane and Johnson Controls. He chaired the ASHRAE Guideline 13 Committee for specifying DDC controls and the oBIX committee to establish XML standards for building controls.