Human-based and automation-based optimization complement each other.
Some optimization measures can be completed by facility staff, “if they have the training and abilities,” notes Pabst. “If not, the BAS technician can perform the diagnostics within the network and update drivers and software.”
In human-based optimization, “you can only look at the building systems or the data from them when you are physically working on them,” Stark points out. “For example, you may inspect a damper and it is working properly. But your inspection is only for a small time frame in proportion to the total operation of that damper.”
Automated commissioning, on the other hand, can look at that damper’s operations over much larger time spans and find certain conditions are causing it to be opening or closing inappropriately.
“This is where automation really shines. You can analyze trended data and see that the damper actually is opening and closing over a longer period of time,” Stark explains.
What’s more, with advanced BAS and analytics, Stark believes more optimization can happen more frequently and for less cost than in the recent past. “If buildings are truly going to be intelligent, the facility manager should not have to wait for a breakdown or wait until the end of the month to find out the energy bill went up,” Stark says. “We should be using the BAS to constantly monitor and optimize and to preemptively tell us that something is going to happen.”
However, Stark also concedes that automation is no match for a highly skilled technician “who can walk into a mechanical room and hear when something doesn’t sound right.” Detecting a pump or fan bearing prematurely wearing out would be harder and more expensive using an automated commissioning system.
“There are just certain things that a person can do and sense that an automation system cannot,” says Stark. “Each has its own strengths and weaknesses, so they both need to be evaluated to see how they work best together.”
Don’t skip these steps
Stark realizes that real time optimization is not always practical or available. Nor do all facility budgets allow for retrocommissioning by independent engineering consultants. For those situations, Stark recommends that the facility management staff perform some basic system checkouts and visual inspections annually.
“If the BAS is allowed to degrade the operation of the systems and equipment it controls, there will likely be a corresponding increase in operating costs,” points out Cooke. “A building, its systems and components are not static, but ever changing.”
Even on a limited budget, some steps should not be skipped. What’s on the basic to-do list for BAS optimization? “At a minimum, owners should have an annual program in which all sensors are calibrated and actuator operation is verified,” suggests Windom.
In addition, both scheduling and overridden set points should be investigated and software updates should be installed regularly. “Most in-house staff should be able to perform these tasks,” Windom says.
Time to act
How frequently BAS optimization should occur depends on many factors. As a rule of thumb, says Cooke, “a reasonable maximum period is every five years.”
However, Cooke says the following factors color how frequently a specific facility actually may benefit from BAS optimization.
• The facility manager’s expertise in building systems and equipment, as well as commitment to the BAS.
• Changes in facility management/engineering staffing.
• Age of the building’s systems/equipment.
• Significant change in hot/cold calls or user/occupant work requests.
• Repeated repairs of major equipment/components.
• Changes or advances in building equipment or BAS technology.
• Major building remodel or addition.
• Major building occupancy change.
• Significant change in energy consumption.
All building automation systems older than five to eight years should have their energy saving performances reviewed, recommends Pabst. “Technology has changed drastically in just the past two years,” says Pabst.
Rita Tatum, a contributing editor for Building Operating Management, has more than 30 years of experience covering facility design and technology.
Email comments to edward.sullivan@tradepress.com.
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