550 Corporate Center Building Powers Down with Open Systems
Built in the early 1990s—when energy costs were low—the all-electric, 20-story, 343,000 square foot 550 Corporate Center building in San Diego was anything but energy efficient. Phased retrofits to the building’s automation system begun in 1999 to incorporate a LonWorks based system from Echelon have resulted in considerable reduction in electrical consumption and assisted in helping the building to win two consecutive "The Office Building of the Year" (TOBY) awards from the Building Owners and Managers Association (BOMA). Currently managed by CB Richard Ellis, one of the largest property management firms in the country, the 550 Corporate Center building was due for a building automation system overhaul in 1999 to meet Y2K compliance. The building’s engineering staff did not want to simply replace the Honeywell Excel system with yet another proprietary system. “The goal was to have a system that was open, flexible, and expandable,” says John Gibson, the chief engineer at 550 Corporate Center. “A system that could truly be managed in-house without having to pay someone to come out and tweak or fine tune it. We believed LonWorks was the future of building automation.” The Power to ChooseSeveral proprietary vendors were considered, but in the end, a LonWorks based system was chosen. To plan and install the new system, Control Contractors, Inc. was selected. CCI, headquartered in Seattle, Washington, with six offices including San Diego, has been designing and deploying building automation systems since 1975. The firm has implemented a number of LonWorks based systems, including one at the W Hotel across the street from the 550 Corporate Center building. LonWorks technology is a non-proprietary architecture that provides an open network to which many systems can be integrated. Selecting a LonWorks based system has allowed the 550 Corporate Center building to pick any LonWorks standards-based products, services, and vendors based on performance, features, and costs without being locked into one vendor. This has been key in getting disparate building systems to work together seamlessly as one to optimize management and energy utilization. It has also allowed Gibson to expand the system in phases to add new capabilities. The first phase of the upgrade in 1999 involved taking control of all of the physical plant and the major air handlers on all the tenant floors, also control of exterior and parking garage lighting within the building. Thirteen Honeywell panels that controlled up to two floors each were replaced with LonWorks compatible Invensys MNL 200 series MicroNet rooftop controllers that manage the chiller plant and air handlers. Other devices tied to the LonWorks network, which runs the LNS® Network Operating System, include Echelon DIO-10s, GE Sontay 20-schedule schedulers, Douglas lighting panels, and an Echelon LPR-12 router for each floor. Because of the non-hierarchical architecture of the LonWorks network, new devices can be added easily. This has simplified subsequent additions to the network, which have included: 4 Invensys MNL 800 series controllers for the parking garage fans and 16 Douglas lighting panels for control of the lighting systems on the tenant floors. Each year, two floors of variable air volume (VAV) boxes are retrofitted with Invensys MNL V2R VAV series controllers. The building-wide network currently consists of nearly 190 nodes. The Power to SaveOne of the key energy savers is the ACS system, which allows tenants to turn on lights and air conditioning after hours. The building’s lights and air conditioning are on from 8am to 6pm Monday through Friday. After hours, tenants can call into the ACS system and turn on lights and/or air conditioning in their area for two, three, or four hours at a time. Lighting is provided at no cost, but tenants are billed for after-hours use of air conditioning by this system. Each tenant has a four-digit ID code, and each user from each tenant has a four-digit PIN code. The system can have up to 9,999 tenants and each tenant can have up to 9,999 users. This is much better than the old system, which only gave the tenants one user code each. As part of its contract with tenants, the building used to run lights and air conditioning on Saturday from 8am until 1pm, whether anyone was in the building or not. “We’d cool 343,000 square feet of space and five people would show up to work in the whole building,” says Gibson. “Now, individual users can turn it on in their areas using their four-digit PIN code when they come in. Even though we don’t charge for Saturday usage, that feature has paid for the system a couple of times over. In addition to that, the flexibility of the LonWorks based system, and the ability to fine-tune it, has been another big factor in saving energy. We were able to cut back on energy just about the time when energy prices were quadrupling in early 2001, providing payback on the entire system that much faster.” After-hours energy consumption is also reduced by a two-stage air conditioning system. Two Trane CDHE 400-ton chillers cool the building during the day. At night, a small, 100-ton Trane reciprocating chiller is left running to specifically cool about a dozen computer rooms for various tenants. Gibson knows that the system is doing what it was intended to do—reduce energy consumption. “Every year since 1999, our electrical usage has trended downward, while occupancy has remained in the 96% to 100% range,” says Gibson. In 1999, the last year before LonWorks implementation began, usage topped 5.4 million kWh. In 2000 the number dropped to under 5.2 million kWh, a 4 percent decrease, as the first phase of the LonWorks deployment was completed. In 2001, with additional LonWorks devices deployed, usage dropped to less than 4.8 million kWh, 11 percent off the 1999 peak. “At today’s average rate of about ten cents a kilowatt hour, that represents an annual savings of about $60,000,” says Gibson. As a result, the building was honored by BOMA for its energy conservation efforts in both 2001 and 2002. Management of the system is accomplished through a Wonderware® front-end that provides a graphical user interface. Gibson uses WorkPlace Tech Tool, a LonWorks compatible PC-based program, to configure and download controller applications. Future enhancements to the system include the refitting of the remaining VAVs. Eventually, Gibson would like to connect the security and parking garage systems into the LonWorks network. This could mean less reliance on outside suppliers. Connecting the LonWorks network to the parking garage access system could also enable the system to automatically turn on the lights or air conditioning in their office as they swipe their card entering the garage after hours or on weekends.
|
||
 |