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899 Northgate Building Slashes Energy Use by 17 Percent with Open Systems

Built in 1987—when energy costs were a fraction of what they are today—the 899 Northgate Drive building in Terra Linda, California, was overdue for an energy-efficiency upgrade. The installation of a Circon Systems building automation system based on LonWorks® technology from Echelon has reduced energy costs, while also making building systems management simpler, easier, and faster.

The 899 building is managed by the Trammell Crow Company, one of the largest diversified
commercial real estate services companies in the United States. Due to an aging system, the building was becoming difficult to manage and costly to run. "The lights and the HVAC were all on an antiquated time clock system," recalls Paul Kerrigan, Chief Building Engineer with Trammell Crow. "It was very complicated, very hard to manage, and if there were any problems, we were down waiting for parts and the system was on override. It was a nightmare. And the tenants could leave their heating or cooling on all night or all day long by turning the thermostat on the wall up or down and we had no control over it. That’s just not cost effective. We needed to do something, and that’s why we made the change."

Building a Case for Efficiency

Kerrigan considered several different alternatives, but after talking with John Clark of Conseil Engineering in Oakland, California, a LonWorks Systems Integrator, he selected a system from Circon Systems Corporation, which develops, designs, and manufactures LonWorks based facility automation systems for commercial, institutional, and light industrial facilities. "John went through the whole system with me," says Kerrigan. "I was sold on it. It was much easier to operate and it seemed like it would be a lot easier integrating it with the existing system we had."

LonWorks technology is a non-proprietary architecture developed by Echelon Corp. It provides the backbone for device-to-device communication and enables many systems to be integrated and managed from a single workstation. Selecting a LonWorks based system allows building owners and managers to choose any LonWorks standards-based products, services, and vendors based on performance, features, and costs without being locked into one vendor.

The new building automation system adapted to the existing equipment. The system controls all of the temperature set points in the building. "I have the ability to change any of the set points if I want hotter or cooler water, cooler temperatures, or zone control," says Kerrigan. Sixty-five Circon UHC-201 HVAC controllers were installed to control each of the heat pumps in addition to two Circon UHC-200 programmable HVAC controllers. The system also integrates with the two cooling towers, two condenser water pumps, two modulating boilers, and two hot water pumps.

To control lighting, six Circon LLC-200 low voltage lighting controllers were installed. These integrate with 12-zone GE lighting control panels on each of the five floors and also control lighting in the parking lot and garage areas.

Two Echelon LonPoint® DI-10 input modules integrate sensors, actuators, and controllers into a peer-to-peer, interoperable network. Five Echelon LPR-10 routers provide networking communications capabilities between all of the building automation system components. These modules and routers create an open, distributed system architecture in which every device performs some control processing and can be accessed from any location in the network. Distributing the processing throughout the network and providing open access to every device lowers the overall installation and life cycle costs, increases reliability by minimizing single points of failure, and provides the flexibility to adapt the system to a wide variety of applications.

The entire system runs on top of Echelon’s network operating software and is managed from a PC using Circon Systems Integrator software. Circon Visual Integrator Graphics software displays the condition of every device connected to the LonWorks network. A quick check in the morning enables the on-site building engineer to instantly identify and pinpoint any problems. An Internet connection even allows Kerrigan, who spends most of his time in the San Francisco office 20 miles to the south, to check the building’s condition remotely. And, this same connection enables Conseil to log on to assist with diagnostic issues. The ability to accurately monitor and respond to tenant- or equipment-related problems has simplified Kerrigan’s job. "I would definitely say it’s easier now. It gives us more time for preventive maintenance and other types of construction. We’ve gone from eight calls a day from tenants to change temperatures to maybe three a week."

Building in Savings

The building is not only easier to manage, but less costly to run. A key element of the building’s energy saving capabilities is the Circon TouchBASe Telephone Override and Billing software, which allows tenants to turn on lights and heat or air conditioning after hours. The building’s lights and HVAC are on from 7am to 6pm Monday through Friday. After hours, tenants can call into the TouchBASe system and turn on lights and heat or air conditioning in their area for up to six hours at a time. Lighting is provided at no cost, but tenants are billed by the system’s billing software for after-hours use of heat or air conditioning. Each tenant has an ID code.

The energy savings realized by the energy management system have been significant. Average monthly kilowatthour usage in 2001, the last full year before installation of the new system, was 84,293 kWh. In 2002, that figure dropped to 71,413. And in 2003, the first full year with the new system, average kWh usage dropped to 66,226, a 22-percent decline from 2001. While approximately five percent of that savings can be attributed to a lighting retrofit, the net savings from the Circon LonWorks based energy management system have been considerable.

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