Building Automation Systems: Experienced Users Discuss Benefits, Challenges of the BACnet Open Data Communication Protocol
By BOM Editorial Staff - May 2005 - Building Automation
Report prepared for the BACnet manufacturers association
Three decades ago, building automation systems — sensors, control devices and wiring — were installed around a single product from a single manufacturer. Proprietary equipment, often from the lowest bidder, meant that facilities executives were locked into a system that might not be the most cost effective in the long run. A replacement part had to come from the original equipment manufacturer, and there was no guarantee that it would be the least expensive. Even worse, changing the building automation system meant changing everything from the control panel and front end to the network and setup.
In organizations with many buildings, the problem multiplied each time a new system was installed. That’s one reason that large organizations have been leaders in the move to BACnet, an open data communication protocol for building automation and control networks. Developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), the protocol allows the open connectivity of BACnet-compliant equipment from different manufacturers and delivers system information to a single front end. It became an ASHRAE/ANSI standard in 1995 and an ISO standard in 2003.
During that time, BACnet has become well–established and widely used, with a growing number of manufacturers offering an increasingly broad array of BACnet-compliant products. Those systems and devices are being used in facilities of all types and sizes. But it is large organizations that pose some of the toughest challenges for open systems. And a look at applications in those organizations shows how BACnet is handling demanding real-world tests.
Open at OSU
Ron Sharpe, manager for building automation at The Ohio State University in Columbus, has had his share of headaches with proprietary building automation systems. He has been involved with control systems since the 1970s, and he knew even then that efficient building control systems had to be interoperable.
“We needed a way that any manufacturer’s system would work with any other manufacturer’s system,” says Sharpe. “If you go with a proprietary system, you get locked in with the low bid. The hook is set.”
BACnet has taken Sharpe and other facilities executives like him off the hook. “BACnet is a true open protocol,” Sharpe says.
Sharpe, a member and past chair of the BACnet Interest Group - North America, has had his eye on the protocol since its beginning in 1987. He admits it wasn’t love at first sight. “We’d hoped for plug-and-play,” he said. “When I read the first review, I was disappointed that it wasn’t plug-and-play.”
Input from potential users improved early versions of the protocol. When Sharpe finally got his hands on a working panel in 1999, it could do everything that he wanted it to do.
“Our local integrator brought out a panel to try,” he says. “I gave it to my head supervisor and said, ‘See what’s wrong with it.’ After two weeks of testing, he came back and said, “I like it. It did everything I wanted it to do, and it is easy to use.”
About the same time, Sharpe faced a catastrophic equipment failure in a lab building and had to decide whether to repair the old system or scrap it and start over. Replacing the system was not much more than buying the parts needed to get the old system running.
The choice was easy. And when installed, the new BACnet system worked as reliably as the test panel. Since then, OSU has consolidated nine building automation systems with different protocols and different front ends to five. Sharpe wants to streamline the operation to one front-end system within the next five years.
“We needed to have a platform that could communicate with multiple vendors to eliminate different front ends and multiple computers,” Sharpe says. “We need to improve compatibility among systems.”
The reason is obvious. OSU has about 12 million square feet of academic and research space. That number is growing as the school continues capital improvement projects. BACnet is installed in about 25 percent of the university’s 149 academic and research buildings. The protocol is used for direct digital control, variable speed drives, chillers, fume hoods and fire alarms. With BACnet, Sharpe and his staff get systems information faster and easier than before.
“If I can’t convert a vendor over to BACnet, we replace it with new,” he says. “We use buildings for about 50 years. If they are historic, we use them longer than that. Most electronics last 10 years. BACnet is good way of staying on top of all that.”
BACnet can also be used for lighting control and other building automation functions. At OSU, for example, elevators will be the next system brought online. With BACnet, the supervisor in charge of that system will be able to monitor their condition and know immediately when and why a car might stop moving. BACnet’s flexibility will allow a customized Web page to pop up when there is a problem.
Central Washington University
Pat Nahan, manager of engineering and resource conservation for Central Washington University in Ellensburg, Wash., has also used BACnet successfully. In 1997, the university was building a state-of-the-art science facility. “Because of the life-safety nature of the science facility, we felt we needed to make an energy control management change,” Nahan says. “Before that, we had a campus wide proprietary system that was cumbersome and difficult to use.”
Selected through a competitive bidding process at Central Washington’s facilities, BACnet brought the school a new level of reliability and user-friendly access to systems through its open protocol delivered to the desktop via Microsoft Windows.
Since the first installation eight years ago, Central Washington has expanded the BACnet-based energy management system to its 30 academic buildings and its central cooling plant. The protocol is used for all heating, ventilation and air-conditioning systems as well as the irrigation well pump.
Combined with energy performance contracts, the system has helped the university make significant reductions in energy consumption.
“When we first expanded the system throughout campus, we were investing in energy conservation measures through $20 million in infrastructure upgrades,” Nahan says. “We have done extensive HVAC upgrades within the existing buildings through performance contracting with an energy services company. Part of performance contracting is to confirm energy savings based on reduced energy costs.”
The upgrades allow the university to manage its energy dollars better — it has reduced electricity consumption by 14 percent and natural gas by 18 percent, despite a 10 percent increase in square footage, Nahan says.
BACnet is now included in all specifications for building construction, including a new music education facility, which includes a lighting control interface.
“In theory, we could use a lot of control equipment that is not manufactured by my EMS supplier,” Nahan says. “If everyone would offer the BACnet interface for every device, we could integrate directly with the energy management system.
“BACnet is an open and published protocol,” Nahan says. “To be BACnet-compliant, manufacturers just have to adhere to specific rules.”
But he says it’s important to make sure that every piece of equipment is completely BACnet-compliant. “Some terminal pieces that are partially
BACnet-compliant use a different protocol at the periphery of the components,” Nahan says.
BACnet will become increasingly important to Nahan as Central Washington opens its new 228,000-square-foot Student Union Building and Recreation Center in May 2006. The $63.3 million project will include full BACnet-controlled integration.
University of Ottawa
Founded in 1848, University of Ottawa, located in the Canadian capital, is one of North America’s premier bilingual universities. Students study in English or French. Like its student body, the university’s building automation systems speak two languages.
The legacy building automation system dubbed UDO I, is a proprietary system, installed in the mid-1980s. BACnet-driven UDO II was installed on campus in the mid-1990s. For now, and for the foreseeable future, these two systems reside comfortably side-by-side. Eventually, they will share the same front end through the use of a browser-based, graphic-user interface.
UDO I was, and is still, doing extremely well on campus, says Phillipe St. Pierre, electricity and instrumentation supervisor in the university’s physical resources services and a member of the team that made the BACnet project successful.
“Over the years, we have been able to upgrade the UDO I front-end software to a Web-based system for less than $10,000,” says Andre Lagault, computing network administrator from the university’s physical resources services and a member of the team. “UDO I will be transferred over to UDO II only through attrition or through major renovation projects that would require the introduction of VAV (variable air volume) boxes or fume hood systems.”
UDO II, the main BAS system, integrates BACnet-compatible devices at a controller level. The University of Ottawa uses BACNet in VAV boxes, fume hood controls and chillers.
“Before the advent of electronic VAV boxes, a building with three HVAC units, two heat exchangers, one cooling control bridge and a bunch of miscellaneous points might cost $60,000,” says Raymond Carrey, lead technician from the university’s physical resources services, and a member of the BACnet project team. “Today with electronic VAV boxes, a BAS system could easily reach $600,000 if we include 300 VAV boxes.” Like OSU and Central Washington, the University of Ottawa turned to BACnet to minimize operating costs.
“Changing a BAS is eventually going to be limited to set-up time and people,” says John Samulack, senior consultant, Ameresco Canada, and a member of the team. “Changing the BAS will be people-based and not product-based. It will be choosing the appropriate company to interface with.”
True to the mission of a university, the University of Ottawa’s biggest BACnet accomplishment has come in terms of education.
“We have managed to educate our local controls contractors in BACnet,” St. Pierre says. “We have been able to minimize finger pointing sessions, and we have managed to get controls contractors to work together.”
Voices of Experience
A knowledgeable, experienced integration team is the key to a successful BACnet integration, facilities executives say.
The first thing Sharpe tells other facilities executives is simple: “Talk to somebody who has used BACnet and has used more than one manufacturer.” He recommends that facilities executives find an integrator who is knowledgeable in networking and control systems. “The integrator is the key to a successful operation. A good integrator knows products from a range of vendors. Our integrator got systems from three vendors up and running on our system when vendors couldn’t do it.”
St. Pierre and Carrey agree that a qualified consultant and support from the university’s network data and communication services is crucial.
“BACnet is still relatively new, and we have found that the problem with new concepts and systems is always due to people and not technology,” Carrey says.
Carrey and St. Pierre say that the industry should focus on training personnel in both technologies — like BACnet and the Internet — and in people skills, like the ability to communicate with others.
“Finding solutions to technical problems is easy,” says St. Pierre. “Once you identify the key people and put them on your team.”
The BACnet Manufacturers Association seeks to promote the successful use of BACnet in building automation and control systems. Interoperability testing, educational programs and promotional activities are BMA’s focus.
Members of the group include companies that design, manufacture, install, commission or maintain control equipment that uses BACnet for communication. BMA membership also includes individuals interested in BACnet.
Among the benefits of membership: participation in vendor interoperability testing sessions, attendance at meetings and seminars, product-testing opportunities, and participation in BMA working groups.
For more information about the BACnet Manufacturers Association, call (312) 540-1200, or log onto the group’s Web site.