Pieces of the Green Puzzle
OTHER PARTS OF THIS ARTICLEPt. 1: Specifying BACnetPt. 2: BACnet: Beyond HVACPt. 3: This Page
Environmental responsibility is second nature to BACnet. By making it easier for facility executives to monitor and control building operational efficiency and comfort, BACnet pays an “environmental dividend” of reduced energy consumption.
Thanks to BACnet’s range of objects, services and networks, the protocol provides meaningful performance data that facility executives can gather quickly, analyze and review to better understand the impact of building occupant behaviors and make better choices for energy management.
“Green building designs specify aggressive targets for improved efficiency and continuous monitoring,” says Brian Dutt, vice president of sales and marketing for Delta Controls. “It is impossible to accomplish these requirements without the use of sophisticated building controls systems.”
There’s a lot of talk about the “triple bottom line” — financial, environmental and social. BACnet fits into the triple bottom line payback model, says Tom Zaban, vice president of sales and marketing of Reliable Controls Corp.
“It really does embody the triple bottom line approach,” he says. “It has an immediate financial ROI simply because it is an open standard that prompts manufacturers to make better products designed to efficiently control building operations and help facility professionals monitor building information and make informed decisions. It has an environmental return because it’s geared toward controlling environments and increasing efficiency. The social return on investment comes from its ability to inform building occupants and to empower them to make change.”
A facility operating a building automation and controls system under the BACnet standard fits comfortably into the U.S. Green Building Council’s (USGBC) Leadership in Energy and Environmental Design (LEED) certification program, both for new construction (LEED-NC) and existing buildings (LEED-EB).
“Building automation and control systems play a critical role, carrying on the intent of green design by providing the application and visibility required to efficiently operate and maintain sustainable facilities,” says Mark Clark, regional manager at Automated Logic Corp. and a LEED Accredited Professional (LEED-AP).
Having a building automation and control system does not provide a LEED credit in and of itself. But effective control is a big piece of the green building puzzle because it helps a facility be energy efficient — which does garner credits. Efficient operations require proper application of controls to an energy efficient HVAC design, executing the intended sequences in a manner that provides a comfortable atmosphere for occupants and maintains efficient facility operation. The proper application of a control system uses a broad base of historical information to provide the operator with tangible comfort values for each of the controlled spaces in the building or the facility as a whole.
What’s more, a building automation system provides the data gathering and historical record keeping required to maintain the intent of sustainable design and to document the operation for the performance period between initial certification and recertification of the building.
To Manage, Measure
Visibility also is essential. What is measured, gathered and reviewed provides a picture of operational performance, while what isn’t collected and assessed is often neglected.
“It’s essential that more information — such as temperatures, carbon dioxide, utility metering and submetering, to name only a few — be brought into the control system,” Clark says. “This information base allows a complete picture of the operation to be developed during building commissioning. It is also the accountability piece — a good control function will gather the historical data that documents the continuing sustainable ideas of the original design. As the connection between various building systems and equipment, interoperability cannot be denied as being an essential piece in the metering and monitoring required in green design. It can provide an additional level of information normally not available or economically feasible.”
This can be done with discrete point monitoring on chillers and more complex pieces of equipment. Interoperability also provides a single point of access for all of the major building systems, offering a more complete information set than would be available by accessing systems individually.
“Having BACnet, as well as the ability to accommodate other protocols and custom applications, completes the interoperability picture,” Clark says. “But interoperability itself is the key — BACnet just makes it happen easier.”
Triple Bottom Line
As important as sustainability has become, green measures aren’t the only things that matter in the design and operation of buildings — even buildings that are LEED certified.
The Aurora Municipal Center in Aurora, Colo., is a case in point. The center, completed in 2002, was certified at the Gold level in the LEED for New Construction program. The building automation system uses BACnet-capable controllers.
“To maintain a LEED certification, a building must continue to operate in a sustainable fashion,” says Terry Hoffmann, director of building automation systems marketing at Johnson Controls. “BACnet provides insurance to obtain and implement the necessary technology to do this at the lowest cost.”
But at the Aurora Municipal Center, BACnet plays a broad role. “BACnet made possible the integration between a comprehensive security management system and a fire alarm system — not just between systems from two different manufacturers but in multiple city buildings as the city expanded its controls upgrade,” says Dave Klee, LEED-AP, director, channel marketing and strategy, building efficiency systems, Johnson Controls.
As the Aurora Municipal Center shows, BACnet isn’t limited to HVAC or even energy management functions. Because it provides a route to interoperability for a wide range of building automation applications, BACnet is an important tool in the design of buildings that are truly high-performance in all areas.