Conservative Powers

mechanical engineering power 2002

conservative powers

Automated comfort controls and new lighting systems aim to cut electricity costs and reduce pressure on the grid.

by Michael Valenti, Senior Editor

Managers of commercial or industrial buildings constructed a decade or more ago are retrofitting them with new controls that optimize heating, ventilating, and air conditioning. By matching HVAC use to demand, the controls are cutting electric bills and easing strain on the local grid, often earning credits from utilities. Similarly, advanced lighting systems are providing needed illumination using less electricity than conventional overhead lighting.

The One Verizon Way building in Thousand Oaks, Calif., earned the top Energy Star award, called the Corporate Commitment Award, on March 26, from the Department of Energy and the Environmental Protection Agency in recognition of improved energy efficiency. The agencies present the awards to buildings whose energy efficiency is in the top 25 percent of comparable edifices nationwide.

"The building's HVAC costs were about $65,000 per month in the winter, and about $100,000 per month in the summer, before we made the improvements," said Denny Harnstrom, chief engineer at Verizon's western regional headquarters. Monthly costs have fallen to $32,000 in winter and $65,000 in summer. Moviegoers might recognize the interior of the building, which has served as a set in a dozen films, including My Stepmother Is an Alien, Demolition Man, and Clockstoppers.

Much of One Verizon Way's improvements are derived from its HVAC control panel and a reciprocating chiller, both designed and installed by McQuay International of Minneapolis. Among users of the company's tailor-made HVAC systems are the Georgia Dome in Atlanta, the Phoenix Library in Arizona, and Nestlé headquarters in Vevey, Switzerland.

The Verizon building in California earned the Energy Star award for improved energy efficiency.

At the Verizon building, McQuay technicians equipped two 325-ton centrifugal chillers and one 109-ton model with its MicroTech and chiller system control panels. They let operators run the chillers based on demand; that is, higher power during the hotter hours. Operating the system with the fewest necessary chillers at near-full capacity improves energy efficiency.

In addition, Verizon uses a chilled water return option. MicroTech controls reset the cooling water supply temperature from 42°F to as high as 52°F to maintain a constant 57°F return chilled water temperature. This earned Verizon a $28,000 rebate from Southern California Edison, Harnstrom said.

MicroTech's open architecture allowed the installers to connect the controls to the building management's personal computers so that the controls can be monitored remotely, as well as on-site.

The McQuay WHR050 water-cooled, dual-compressor reciprocating chiller used to cool the computer data center ran at reduced loads, cutting costs.

Verizon also installed a McQuay WHR050 water-cooled, dual-compressor reciprocating chiller to cool the building's computer data center to further trim energy costs by running at reduced loads. The 50-ton chiller replaced two original 10-ton hermetic compressors. "These units had difficulty cooling the new computer server rooms that were added over the years, and the old data center housing additional computer systems," noted Harnstrom.

The WHR050 is connected to the building's chilled water loop and backup condenser pump, but is programmed with MicroTech controls. At night and on weekends, the McQuay chiller provides cold water to eight chilled water fan coil systems running at 25 percent of full load to maintain temperature.

Illuminating Savings

Lighting, which consumes up to 40 percent of a facility's electrical costs, is another target for increasing efficiency. Advanced lighting systems are cutting expenses by illuminating specific work areas with a required level of brightness. The Lighting Systems Research Group of Lawrence Berkeley National Laboratory developed a table lamp that provides the same illumination as a 300-watt halogen lamp or a 150-watt incandescent table lamp, but uses less energy than either one. Named the Berkeley lamp, it was funded by the Department of Energy's Office of Building Technologies and the California Energy Commission.

The lamp is designed to replace halogen torchieres and standard fluorescent overhead fixtures. The lamp draws less electricity than the one, and wastes less light than the other.
Fluorescent overheads illuminate an entire office space to the level required for detailed task work, but usually only desktop work spaces actually need that kind of lighting, according to Erik Page, a mechanical engineer and staff research associate at Lawrence Berkeley. The first person in an office at 6 a.m. who turns on the overhead lights consumes much more energy than by lighting an individual desk lamp.

The Berkeley lamp consists of two independently controlled, compact fluorescents, both of which cast less heat than halogen lamps and can be fully dimmed. One fluorescent lamp will shine its light downward directly onto the working surface. The other aims its light upward to provide indirect lighting.

The Berkeley lamp's designers placed an optical septum—an aluminum reflector dish painted white—between the two lamps to permit three different modes of lighting—down, up, or a combination of the two. The downward, directly focused light is intended for reading or writing, and the indirect, upward light for low glare, suitable for working on a computer, Page said. The combination serves when the worker is busy shuttling between paper and keyboard and, in all modes, uses standard 120-volt current.

Dimmers regulate the level of illumination from 10 to 100 percent, so workers can adjust light energy to what they actually need in a changing environment, for example, on a sunny day.

The lamp's designers arranged the shade, fluorescent elements, and septum to provide a uniform light, minimizing hot spots, which are areas of concentrated brightness.

Designing the optical septum was the singular challenge of creating the lamp, according to Page. "We equipped our first prototypes with a relatively flat septum that only partially separated the light output," he said. "We then extended the edge of the septum to mate with the top edge of the lampshade's upper aperture to completely block the two light modes. However, because this cast an unattractive shadow on the top three inches of the shade, we worked on the optics and curve of the septum to eliminate the shadow."

Last summer, a hotel in Sacramento replaced the banker's-type desk lamp (left) with the Berkeley lamp in its guest rooms in order to test its relative efficiency.

In a test last November, the City of Berkeley defied superstition and installed 13 of the original lamps at a building it leases for its draftsmen. The building was equipped with older, magnetic ballast fluorescent overhead lights. Besides being less efficient than modern electronic ballast overheads, the older ones often hummed and buzzed like a beehive, and emitted a harsh light.

"Proper lighting is critical for these people, who draw on real desktops as well as on computer screens," said Neal De Snoo, energy officer for Berkeley's housing office. De Snoo is responsible for implementing the office's energy conservation programs and, with three years to go on the drafting building's lease, determined that using the new table lamps would be cheaper than replacing the lighting with new overheads.

"We installed the Berkeley lamps on desktops and some common areas, and asked workers to turn off the overhead lights in those areas," De Snoo said. The housing office also attached electric meters to the lamps and the overheads to measure energy consumption over two weeks, and found that the Berkeley lamps cut energy use in half in their work areas.

"Although they were originally skeptical, the lamps' users tell us the lamps provide a more inviting, warm light than the old overheads, and they appreciated the ability to use the dimmer to regulate illumination," De Snoo said.

The city has since ordered another eight Berkeley lamps, and plans to purchase more, not just for city use. "We intend to retail Berkeley lamps to promote energy efficiency in the private sector as well," De Snoo said.

Another beta site was the Hilton Doubletree Hotel in Sacramento, which installed 200 Berkeley lamps in its guest rooms last August, with the assistance of Lawrence Berkeley and the Sacramento Municipal Utility District. "We replaced the existing banker's-type desk lamp with the Berkeley lamps in both suites and single bedrooms because insufficient lighting was among the top 10 complaints we received from our guests," said Bob Hughes, the regional director of engineering for Hilton Hotels. The old lamps also incurred significant labor for repair and replacement.

Hughes said that Doubletree guests often use the Berkeley lamp exclusively, without turning on overhead lights, reducing energy consumption. "Both lighting complaints and labor costs to replace failed parts have dropped significantly since we switched to the new lamps," Hughes said.

In December, Light Corp. of Grand Haven, Mich., began marketing the lamps. Light Corp. specializes in fabricating lighting for office furniture manufacturers, including Hon, Herman Miller, and Steelcase. By April, the company had sold more than 2,000 Berkeley lamps, at a suggested retail price of $265 each, according to product manager Tom Volkema.

"We're generating the most interest on the West Coast and Hawaii, where there are concerns over energy shortages," said Volkema. Customers have cited the pleasing quality of the Berkeley lamp's light, which is opening some interesting niche applications.

"Colleges are using the Berkeley lamps in dormitory rooms, hospitals are installing them in patient rooms, and more upscale hotels want them for executive suites equipped with work spaces," Volkema said. "We are also hearing from architects who are under pressure from clients that specify new construction for innovative ways to minimize energy usage."