We all have them — Blackberries, laptops, maybe even a Bluetooth-enabled global-positioning system for a car. Wireless technology has become a pervasive part of our everyday lives and, in many cases, is something we take for granted, with its ease of use and convenience. Most of us cannot imagine life without it.
However, we did not get here overnight or without having to overcome many obstacles. There also is much more to wireless than just consumer devices. Imagine this scenario: A facilities engineer is notified automatically via his mobile device that wireless sensors have detected a performance anomaly with a rooftop unit. Using the browser on his personal digital assistant, he immediately issues a command to stop the equipment, preventing damage until he can investigate. The engineer goes to the point of the problem, assesses the situation, and, using the same device and wireless network, downloads the manufacturer's support documentation to help him address the issue. Once the repair is complete, the engineer verifies and tests it using a wireless diagnostic tool and places an order to replenish parts used on the job. This scenario creates relatively little labor and downtime, no equipment damage, and a fast, cost-effective resolution.
Wireless technology is evolving to become a more attractive option for broader monitoring and control of building systems. However, wireless is not a panacea for all building automation. There are implementation risks and application issues to consider before committing time and resources to a wireless-enabled solution.
Wireless can be a cost-effective and non-disruptive way to monitor and maintain building-automation systems and the comfort and security of building occupants.
Wireless can enable faster installations and easier maintenance. It can be a good solution for existing-building retrofits in which extensive demolition or rewiring would be required or there are restrictions prohibiting building alterations, such as the presence of asbestos or historical-preservation guidelines. Wireless also allows builders to reduce labor and materials used during new construction. This helps create a more flexible environment for future changes in space requirements and earns points toward Leadership in Energy and Environmental Design certification, among other benefits.
When done right, wireless helps facility managers network and integrate data from multiple access control points, centralizing the management of lighting, heating, cooling, and security systems for reduced cost and optimized operation.
For instance, HVAC and lighting-control systems generally are good candidates for wireless. These systems tend to have stable wired protocols, such as BACnet or LonWorks, which provide a standardized information-technology (IT) foundation for data sharing. As a result, the wireless transfer of data has more value among systems and can be deployed with lower risk. Using wireless for these types of building systems makes sense in spaces in which it is difficult or impossible to run wire, such as a large atrium.
Metering is another area in which wireless frequently makes sense. As facility managers try to stabilize energy costs and reduce carbon footprints, there is a need to have greater insight into energy use across multiple areas of a facility, not just at a single metering point. By implementing a smart metering system, organizations can better understand energy-use patterns in different areas of a facility through sub-metering and implement strategies to reduce consumption. Wireless technology makes adding energy data-collection points simple and cost effective, enabling information to be fed into a central management system for improved analysis. Using data to better manage energy consumption also can have a favorable impact on rate structures and significantly reduce annual utility costs.
While many recognize the inherent benefits wireless delivers in allowing facility managers and contractors to extend and upgrade building infrastructure with minimal effort, there have been several barriers — and misperceptions — that have slowed widespread adoption.
According to a recent Frost & Sullivan study, interference and reliability are the primary concerns with wireless solutions. Many people in the construction world have taken a cost/benefit approach in comparing the reliability of wired and wireless systems, as wired systems have proven themselves to be dependable over the lifespan of a building control system. If there are issues with a wireless system after a building is constructed, contractors are forced to correct the situation, potentially eroding their margins. However, with the advancement of wireless networking technologies, such as “self-healing” mesh networks (Figure 1), and improved data recovery, the reliability of wireless systems is nearing that of copper.
Facility managers are becoming comfortable using wireless for non-critical applications in which there is less risk in a temporary loss of coverage. However, high-risk components of an HVAC system typically will remain hard-wired. The control of critical valve or pump operations, for example, usually requires the level of reliability currently associated with direct wired connections. But there are a number of applications, such as the use of wireless sensing and control providing tenant comfort, in which a momentary loss of communication would not impact comfort.
Wireless has been perceived by some people to be too expensive, which is one reason why it often is not specified when buildings are being constructed. However, with the continually increasing costs of copper and labor, wireless technology has now matured to the point at which it can deliver a lower total installed cost vs. a comparable wired system.
In addition, when examining ownership expenses over a facility's life cycle, construction costs are only 20 to 25 percent of an outlay. Five years after a building is completed, new tenants may come in, new space requirements arise, demolition takes place, and new wiring is run. Specifying wireless technology up front enables facility owners to avoid many of these associated costs and gives them flexibility in managing space requirements.
During a retrofit, wireless technology allows contractors to more easily complete installation and make changes without disrupting the work of tenants or creating a host of problems in the discovery of hazardous materials when walls and ceilings are exposed.
However, not all installation costs are mitigated with wireless technology. For example, power still is required to drive the actuators on a variable-air-volume box, so technicians still must run electrical wiring.
Facility managers are interested not only in controlling temperature and humidity levels, but in ensuring that equipment and systems operate at an optimum level. Often, existing buildings are wired for temperature and control systems, but those who wired them did not take into consideration some building-equipment “vitals,” such as motor performance in rooftop units. Gathering this type of data wirelessly can be helpful in predictive fault protection and predictive maintenance, lowering overall costs and ensuring automation systems are operating at their best.
Wireless networking technology is improving continually, and there are many secure wireless solutions for facility managers and builders to choose from based on their specific requirements. Some wireless solutions operate on a proprietary platform, which can make sense for niche applications. On the other hand, those interested in deploying a comprehensive wireless system across an entire facility often gravitate toward technology that adheres to more open standards when consistency and flexibility are desired.
For example, Bluetooth is a common protocol used for wireless headsets and numerous other applications. ZigBee is an emerging standard for low-cost, low-power applications to meet the needs of many commercial and residential building applications. There are differing levels of data-communication security and device authentication associated with these implementations to help ensure system reliability.
Traditionally, building management systems have focused on maintaining occupant comfort, putting less emphasis on measuring the actual performance of equipment. Adding wireless technology to an existing wired system at strategic points can help facility managers extract information that otherwise is not being measured, usually at a much lower cost than running new cable. This often is referred to as “condition-based monitoring.”
Wireless sensors can alert a facility manager to a change in the acoustical noise signature of a bearing, for example, indicating the need for servicing. Collecting additional data through wireless also can help engineers predict how well a building is operating to maintain certain environmental ratings or meet state and federal regulations.
In addition to measuring building-equipment performance, most wireless solutions have built-in capabilities to assess their own health. Measuring bandwidth, latency, how many nodes are connected, conditions of batteries, and signal strength can help facility managers anticipate and prevent outages and coverage gaps for optimal building-system performance.
Proper design and implementation of a wireless infrastructure is critical to a system's success. This is the case regardless of whether a system is a retrofit or is installed in a new building.
Engineers first must evaluate the type of facility, the wireless equipment available, and specific performance characteristics to make sure an application is appropriate. For example, high-wattage dishes used for broadcasting in sports arenas might cause interference with some types of wireless technology. Thus, wireless may not make sense in such facilities. Other potential interferences could be elevators or structural objects, such as large concrete pillars or foundations. A rough checklist of questions to consider includes:
Are there potential interferences with other wireless frequencies (Figure 2)? If there are, does the IT department need to be involved to help sort out the issues?
Are there any foil-backed gypsum or shielded rooms, metal floor pans, or roof decking that will degrade radio-frequency coverage?
Are the vendor product specifications aligned with the application requirements, such as range capabilities, environmental specifications, system tool requirements, etc.?
Have maintenance and battery-life concerns been considered?
Structural issues should be a key concern when evaluating the potential for wireless in a facility. If an existing building has severe limitations with regard to existing wireless technology (i.e., poor cell-phone reception), it may not be a good candidate for wireless because the expense to implement may far outweigh the benefit.
Wireless technology has come a long way over the last five years, emerging as a cost-effective and reliable option for existing facilities and new construction. As the application of this technology increases, more facility managers and contractors will recognize the benefits of wireless-enabled solutions for building automation.
For past HPAC Engineering feature articles, visit www.hpac.com.
Jerry Borchardt is a program manager for Honeywell Environmental and Combustion Controls. Mark Cherry is the global platform and applications manager for Honeywell Building Solutions. Both organizations are business units of Morristown, N.J.-based Honeywell International.