Consulting-Specifying Engineer - May 2008 - (Page 12) M/E Roundtable PARTICIPANTS Wireless controls The advantages, future, and obstacles facing the development of wireless Jim Kohl Senior Product Manager Trane Commercial Systems Piscataway, N.J. controls are discussed with this month’s panel of experts. BY MELISSA HILLEBRAND, Associate Editor CSE: What are the advantages of wireless controls? TIM KUHLMAN: As with other systems that use wireless, it allows for more flexibility in making connections in the system. It can lower the cost of construction by not having to route cabling in areas that are inaccessible or where conduit penetrations can be expensive or problematic. There are advantages to avoiding a roof penetration or routing conduit through an ornate building lobby to make a control system connection. STEVE TOM: The primary advantages of wireless controls are reduced installation costs, particularly in retrofit projects, greater flexibility, and better architectural compatibility in some situations. The reduction in installation costs comes from no need to pull communication wiring to the device. This is especially advantageous for battery-powered wireless sensors, as there is no requirement for power wiring either. It also is an advantage for externally powered wireless controllers, as running wires to the nearest source of power may be easier than pulling communication wiring throughout the building. Greater flexibility stems from easily repositioning controllers and sensors after installation to accommodate building reconfigurations or new construction. The architectural compatibility issue primarily relates to wireless sensors, as they can be mounted on marble, concrete, historic structures, etc., where drilling is not practical and exposed wiring is not acceptable. KEITH LANE: The advantage of installing wireless technology within a commercial building is the potential reduced cost of installing a conventional wired network. The cost per control point for both lighting and HVAC systems can be reduced when using wireless controls. Building owners, especially those looking for a LEED-certified building, want the most energy efficient and occupant friendly building at the lowest costs. There is sometimes a compromise between the initial cost of control points within an energy management system and the ability to control the HVAC system based on having real time accurate data. Lower-cost wireless controls allow for more effective operation of energy managements systems and as a result a more efficient building. Wireless control integrated into lighting systems also allow the occupant more control of his or her work area. JIM KOHL: Wireless controls offer users a greater level of location flexibility for better sensing accuracy. Wireless controls also offer reduced installation times, especially in renovation projects, and lower relocation costs. CSE : What obstacles impede wireless controls? TOM: The primary obstacles that impede wireless controls are an increased potential for communications failure, potentially increased maintenance costs, and a lack of long-term experience with wireless controls. Conventional wired control systems have excellent reliability. On rare occasions noise from nearby equipment can create communication problems. Once installed, they tend to work flawlessly for decades. When problems do occur, troubleshooting and correcting them can be much more time consuming than with wire led networks. Tim Kuhlman, PE, RCDD Electrical Engineer CH2M Hill Portland, Ore. Keith Lane, PE, LEED AP Principal/Partner Lane Coburn & Assocs. LLC Seattle Steve Tom Dir. of Technical Information Automated Logic Kennesaw, Ga. 12 Consulting-Specifying Engineer • MAY 2008
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