Home > Issue by Date > November 2006

IMAGE CREATED BY JEFF CLAPP, CREATIVE DIRECTOR; PHOTO ©2006. IMAGE AT TOP PROVIDED BY WIREMOLD/LEGRAND

Wireless: Generation Next

As wireless sensor networks evolve, the potential benefits for facility management operations are increasing.

By Anne Vazquez

Many facility managers have discovered how wireless technology can boost the performance of their buildings, both publicly and behind the scenes. Access to a cell phone signal and the ability to log on to the Internet using a laptop are expected by occupants in most buildings today. Facilitating such activities in their buildings has required many facility managers to install equipment and implement strategies to maximize signal strength.

Additionally, wireless technology is being used more and more to control building automation systems. The continued development of wireless sensor networks for building controls is beginning to make the technology more visible to potential end users. Learning more about wireless building controls systems can help a facility manager to determine if the cost and benefits of the technology are a good fit for a particular building.

Problem Solving With Wireless Controls

When Russell Hussey, building manager at the Newburyport Masonic Temple in Massachusetts, needed to lower energy costs and gain greater control of the indoor environment of the facility, he did not initially expect wireless technology would provide a solution. However, he eventually learned that such an approach to an HVAC upgrade would not only solve his problems, but it would also address two related concerns—budget constraints and preservation of the building’s historic structure.

Built in the early 1800s and upgraded in 1929, the 24,000 square foot building Hussey manages relied on an aging control system for heating operations in 10 zones. These zones were unable to communicate with each other, and only two were able to control the boiler. The facility’s inconsistent operating hours also contributed to unnecessary energy consumption, since Hussey was not always present to turn the system off when it was not needed.

These control and monitoring issues could be addressed by installing an automated system, but there were issues of cost along with concerns over penetrating walls to install wiring and related infrastructure.

In the end, a wireless building controls system solved Hussey’s problem. Existing thermostats were replaced with wireless controllers and digital sensors; each zone in the building was linked to a master controller; and Hussey can now view and control all the system elements from his computer. Since the required wiring was minimal, this solution saved on installation costs and eliminated the need to alter the structure.

Wireless Coming Of Age?

The story of the Newburyport Masonic Temple illustrates several points about the potential for wireless technology in the realm of facility management. While some in the profession have adopted building automation controls based on wireless technologies, the application is not widespread.

Facility managers are generally concerned with the cost, reliability, and security of wireless building automation controls. With this in mind, some take the leap from freestanding, independent building controls to a completely integrated, wireless automation approach. Others already have facilities with building automation systems and consider weaving wireless technologies into the existing infrastructure.

As president and founder of Building Intelligence Group, a consulting firm in St. Paul, MN, Paul Ehrlich, P.E., works with facility professionals who are implementing building automation systems, both wired and wireless.

“Regarding building controls,” he says, “we see managers and owners looking for two things. The first is the ability to make their staff more productive by being mobile with the ability to receive a work order or troubleshoot a problem without having to be in an office.”

In terms of a wireless solution, Ehrlich says, “Wireless building controls provide a benefit in the form of dramatically reduced costs as well as the flexibility to relocate or add sensors to the network easily.”

Ankit Shukla, a research analyst with Frost & Sullivan, a growth consulting company based in Palo Alto, CA, who has researched the issue of wireless building automation, says, “With wireless technology finding greater adoption in building automation, the number of addressable applications is large. Seen in both a supportive and/or disruptive role with existing wired infrastructure, wireless technology has opened many new fronts.

“As part of a wireless sensor network, sensors provide information about the physical world around us,” continues Shukla. “And their mass deployment in building areas that are difficult or very costly to wire can be addressed via the use of wireless technologies.”

Shukla notes that the first wave of wireless sensor products for building management has consisted largely of sensors used to measure carbon dioxide, temperature, and pressure. He terms these “under the ceiling” applications, as opposed to wider building management systems such as HVAC, lighting, and security.

Accommodating The Facility

The use of wireless sensor networks can present cost benefits on the installation end. In many cases, implementing a wireless system will be less costly than a comparable wired system, due to less wiring and the fact that the installation process may not be as labor intensive.

Jon Williamson, product marketing manager at TAC in North Andover, MA, says, “The power of wireless is in its ability to solve installation problems. This includes when a project is considered too costly due to the installation of wires; when the installation is too difficult because of building materials and wall penetrations; or when the installation is too damaging to a historic building. In any of these situations, wireless provides an excellent and cost effective solution.” TAC performed the installation at the Newburyport Masonic Temple, where all of these issues were present.

Williamson adds that wireless can also be appropriate when maximum flexibility is required, such as in modular office spaces that are frequently changed.

Says Linda McDaid, senior install market manager at Honeywell Building Solutions in Minneapolis, MN, “As [the cost per point] comes down, wireless will be used more and more in the new construction arena to lower total install costs. Applied in the right building type, there will definitely be a benefit of reduced costs.”

However, this is not always the case, and each facility has specific conditions and requirements that may or may not make wireless the best choice. Structural issues should be a key concern,” advises McDaid. “If an existing building has severe limitations with regards to existing wireless technology—for example, if cell phone reception is poor—it may not be a good candidate, because the expense to implement wireless may far outweigh the benefit.”

Regardless of whether the system is going to be installed in a new or existing building the proper design and implementation of the wireless infrastructure is critical, according to McDaid. Much depends on the expertise of the engineering team.

Standards Helping To Reduce Costs And Increase Reliability

Over the past few years, the costs of the devices used to create a wireless sensor network in a building have decreased. The emergence of standardization for the technology is one reason for this evolution.

In 2003, the Institute for Electrical and Electronic Engineers, Inc. (IEEE) introduced the 802.15.4 Standard for Low-Rate Wireless Personal Area Networks (WPANS). A general definition of a WPAN is “a network for interconnecting devices centered around an individual workspace,” with the objective of facilitating seamless operation among devices and systems.

The applications addressed by IEEE’s Standard 802.15.4 are characterized by low data rate, low power consumption, and low complexity. This focus aligns with the function of wireless sensor networks used for building management applications.

Unlike cell phone and Internet use, which require a constant signal in order to be powered, building automation control systems do not need to access the wireless signal constantly. They are able to “power down” between active use. Additionally, when data is transmitted through the network, the information for a building management system is significantly less than the data volume for cell phone and Internet use.

Says Shukla, “Cost associated with the current state of wireless technology, which is based on ratified protocols, is going down tremendously. The key is whether wireless technology is a ‘nice to have’ or a ‘have to have.’ The cost reductions will eventually turn most of the ‘nice to have’ scenarios into ‘have to have’ scenarios. This will also take place once wireless products and solutions have proved their performance and reliability compared to traditional wired technology.”

Working in concert with the specifications contained in IEEE Standard 802.15.4, the ZigBee Alliance began developing communication protocols that would build on IEEE’s low data rate and low power consumption goals. The ZigBee Standard, which was ratified in 2004, adds a significant building block to a uniform wireless infrastructure, since it was designed and optimized specifically for sensor network applications.

Bob Heile, chairman of the ZigBee Alliance, notes two advantages of the organization’s standard that are also making it cost-effective for manufacturers to use—complexity is low, and the technology is mature.

“ZigBee chose a radio technology and modulation scheme which is the same as [IEEE] 802.11b [existing Wi-Fi], so there is a lot of fabrication experience,” explains Heile. “The technology is well understood and inexpensive. Yet, because ZigBee is a low data-rate solution, tolerances on both the transmitter and receiver are a lot more relaxed than they need to be for 802.11b, thereby increasing yields and further reducing costs.”

 

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