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Smart buildings get smarter

Robert L. Mitchell | Oct. 23, 2012
Behind the glittering, sculpted glass skin of the San Francisco Public Utilities Commission's new 13-story headquarters beats the heart of one of the most energy-efficient office buildings in the world.

Saving Energy

Sometimes Fingers Are Better Than Sensors

There are a number of high-tech tools that can help organizations save money and cut energy use by automating building controls, but sometimes the best option is a manual switch.

Consider the case of Union Hospital in Terre Haute, Ind. When officials wanted to save energy in operating rooms, the first thing they did was to stop relying on occupancy sensors to control the air conditioning.

That move might seem to be counterintuitive. Operating rooms require 15 or more air exchanges per hour when in use, and turning down the air conditioning when a room is unoccupied can save a lot of energy -- potentially cutting costs by as much as $10,000 annually per room. The problem was that hospital staffers move in and out of the surgical suites all the time, so the occupancy sensors, which worked fine for lighting, couldn't efficiently control the ventilation system.

CIO Kym Pfrank's next move was to try a product called the Healthcare Environment Optimization (HEO) system from building automation system vendor Johnson Controls. HEO can be integrated with a hospital's surgery scheduling system, and Union Hospital could have configured the software to turn the air conditioning in surgical suites on and off in concert with the surgical schedule.

But that wouldn't have worked either.

"The schedule flexes too much, so you still need a [manual] control" in each room, says Pfrank.

Another option would have been to take advantage of functionality in HEO that activates a room's air-conditioning system when a patient's ID wristband is scanned. But in the end, the surgical teams said that they preferred to activate and deactivate air conditioning manually using the system's touch-screen monitor. Now, a staff person touches the screen when a procedure is about to start and then touches it again when it's over, so HEO can throttle back the air exchanges to five per hour.

"We're still dependent on the human element," says Pfrank. "I don't know that that can be ever taken fully out of it."

-- Robert L. Mitchell

Both energy-efficiency optimization and fault detection and diagnostics are based on rule sets that are typically customized for each project. The rules determine whether equipment is operating efficiently; if there's a problem, the system performs tests to find the cause.

The SFPUC's rules, which were developed using a spreadsheet-based energy analysis tool called eQuest, also calculate the increased cost associated with running a system out of specification. When a critical event occurs, the IBMS can automatically generate a work order in the facilities management system, says Sinopoli.

Microsoft's engineers created 195 rules and used SQL Server's Stream Insight event engine, along with analytics software from Iconics, to perform calculations that identify faults and monitor efficiency. "We not only find the faults, but monetize them," says Smith. For example, variable air volume (VAV) boxes control airflow in the air conditioning system. If one of the 20,000 VAV units isn't properly calibrated, the system alerts the facilities group before any employees call to say they're uncomfortable. The rules also calculate the energy cost savings that would result from fixing the problem, allowing the facilities group to prioritize the work. "We went from walking around to figure out what's not working to figuring what's not working and costing the most. That saved us over $1 million right there," Smith says.

 

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