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Part 2: Direct-Digital Controls: Energy Management Lowers Utility Costs
By Dan Hounsell, Editor
May 2011 -
Building Automation Article Use Policy
Wilhelm stresses the ongoing need to bring the benefits of DDC technology to university facilities so system operators can more efficiently control HVAC systems and components. The technology enables operators to more closely control a range of operations. They can route alarms to various locations on the network. Technicians can more accurately diagnose and troubleshoot system and control problems. The technology also allows operators to view system data in various formats, as well as store and analyze data to monitor trends in equipment performance.
Wilhelm also emphasizes the role of DDC technology in achieving UNLV's energy goals. Since 2001, energy-management efforts — from BAS and lighting system upgrades to the installation of variable-frequency drives and new chillers and boilers — have enabled the university to avoid about $12 million in utility costs.
DDC system operators can easily implement such energy-management strategies as demand monitoring and limiting, and they can monitor and control overall demand to a facility by changing system setpoints based on demand levels. They also can schedule components to turn on or shut off in areas of facilities where occupants' schedules change frequently.
Another important goal of the BAS upgrade is to expand the campus's level of control standardization. Several campus buildings already feature the DDC system now operating in the chemistry building.
"When you have numerous systems (from different vendors), you don't have integrated control, where you can monitor numerous buildings at one time," Wilhelm says. Because other buildings use the manufacturer's BAS, the department does not have to invest as much in training technicians to operate and maintain the system.
Standardization, he says, "is the ideal. If you have multiple systems, it requires so much more knowledge, and we're limited by the number of people we have on board. It's hard enough to learn one system, much less two or three. You at least want to have a modicum of commonality among systems."
As a veteran of BAS upgrades, Wilhelm offers suggestions for ensuring the project unfolds as planned to avoid wasting precious resources. One important lesson involves reviewing the job site thoroughly before work starts.
"The more you survey, the less chance you'll have problems with the project," he says. "You have to put your eyes on what's going to be done, everything you're going to touch. That will prevent some problems down the road."
As an example, he cites one challenge the chemistry-building project presented. The contractor performing the upgrade reported that workers could not access a controller in one location because, at some point, workers had installed ductwork for a laboratory fume hood above the drop ceiling and right next to the controller. Wilhelm had to call in another contractor to move the ductwork to allow the BAS upgrade to continue.
Managers also should be sure to start the planning phase of the project with a clear scope of work.
"If it's too general, you might not end up with what you need," he says.
Wilhelm also advises managers to take advantage of any available funding to bring the benefits of DDC technology to facilities.
"We're state funded, so we only get so many dollars," he says. "We have to apply them within the limits of the budget. So as money becomes available, we do it.
"But if it's possible to get the money, it's a wise thing to do."
Tapping into the Power of DDC
Part 1: Direct-Digital Controls Improve Equipment Monitoring
Part 3: Product Focus: HVAC