Direct-Digital Controls Improve Equipment Monitoring

By Dan Hounsell, Editor  
OTHER PARTS OF THIS ARTICLEPt. 1: This PagePt. 2: Direct-Digital Controls: Energy Management Lowers Utility CostsPt. 3: Product Focus: HVAC

Upgrading a building-automation system (BAS) can be an immense undertaking, given the complexity of the technology and the need to dovetail it to fit a facility's existing systems and operations. But for the University of Nevada, Las Vegas (UNLV), such projects have become nearly routine.

"We've been through so many of them that by now we have all the bugs worked out," says Jim Wilhelm, assistant director of energy management with UNLV, who has been involved in BAS upgrades in about 15 facilities, many on the UNLV campus. So when the timing was right — and the funds were available —contractors began work to bring the operational benefits of direct digital control (DDC) to the university's chemistry building.

The project has brought an additional benefit to the campus. Because the system is from the same vendor as many other building control systems on campus, it has extended the ability of system operators to more closely monitor and control HVAC systems and components. One result is energy savings that have become so crucial for institutional and commercial facilities.

Harnessing DDC

The campus's 48,000-square-foot chemistry building was constructed in 1972. It houses a mix of classrooms, offices and laboratories. Among the main drivers of the BAS upgrade was to address the growing number of too-hot and too-cold calls Wilhelm's department was receiving from building occupants.

"Our main objective was to get the building under better control so we're able to control and monitor it more effectively," he says. "With a pneumatic system, you can't really monitor anything."

Planning for the $300,000 project — which offers a payback of about 10 years — started in September 2010, the actual upgrade started in January of this year, and work was completed this month. The project called for removing the existing pneumatic control system — the building's original system — keeping the existing variable-air-volume boxes, and replacing the control system with a DDC system to better control the operation of boilers, chillers, pumps, motors and related components throughout the building.

"DDC systems are so much more controllable," Wilhelm says. "It's easier to troubleshoot. You can sit at your desk and monitor everything. They allow you to run the minimum amount of capacity in terms of chillers and boilers."

DDC systems use microprocessor-based controllers, as well as converters that transform analog data into digital signals. The technology provides more effective control of HVAC systems by giving system operators more accurate data on temperature, humidity and pressure conditions in the space. The DDC systems also can integrate into control systems for fire, access, and lighting, as well as computerized maintenance management systems.

Continue Reading: Tapping into the Power of DDC

Direct-Digital Controls Improve Equipment Monitoring

Direct-Digital Controls: Energy Management Lowers Utility Costs

Product Focus: HVAC

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  posted on 5/13/2011   Article Use Policy

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