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Research Highlights

Energy-Efficient Fume Hood To Begin Field-Testing Phase

After passing industry standards for safety and containment earlier this year, the energy-efficient high-performance fume hood will begin field testing this summer. Current research has reduced air flow to 30 percent of a typical hood installation. Because less air is flowing through the hood, a building's environmental conditioning system can be downsized, saving both energy and initial costs of construction.

The revolutionary low-flow fume hood technology began development under supervision by Helmut Feustel in 1995. The U.S. Patent and Trademark Office has issued a patent for the technology. The Applications Team's Geoffrey Bell and Dale Sartor are currently leading the research team. Field testing will take place at Montana State University (MSU) in Bozeman and at the University of California, San Francisco this fall. Both testing phases will run for several months. MSU is working with a national team including Berkeley Lab to design a 21st century academic laboratory that will function as a showcase for environmental stewardship.

Beth Shearer, Tatiana Muessel and A-Team's Geoffrey Bell view the fume hood.

Beth Shearer (right), director of DOE's Federal Energy management Program, and Tatiana Muessel, the Project Financing Team Leader, get a demonstration of the energy-efficient fume hood from A-Team's Geoffrey Bell.

The Berkeley Lab high-performance design uses a "push-pull"approach to contain fumes and move air through a hood. Small supply fans, located at the top and bottom of the hood's face, gently push air into the hood and into the user's breathing zone, setting up a "divider"of air. The air divider helps prevent fumes from reaching a user standing in front of the hood and pushes air toward the hood's exhaust outlet. Consequently, the fume hood's exhaust fan can operate at a much lower flow.

To measure the effectiveness of the hood, the research team is testing air flow through the hood by various means. For example, the team has used a schlieren system to help visualize air flow inside the fume hood. The schlieren system enhances natural light diffraction caused by air at different densities, so the diffraction can be seen on camera with temperature differences of as little as 3°F.

The Applications Team is partnering with several industry leaders to disseminate information on the fume-hood technology. The research team is working with Labconco, a prominent fume-hood manufacturer, to enhance the current fume-hood design. The team is also partnering with ATMI, a semiconductor distributor, to apply the containment technology to applications in the microelectronics industry, such as for wet benches. The low-flow fume hood was showcased at this year's Laboratories for the 21st Century conference, which was held from September 6-8, 2000 in San Francisco, CA. Berkeley Lab was one of the organizers of the conference. Visit the Lab 21 Web site.

— Annie Tsai

For more information contact:

Dale Sartor

(510) 486-5988; fax (510) 486-4089

Geoffrey Bell

(510) 486-4626; fax (510) 486-5394

Unusual Approaches to Investigating Energy Efficiency

Berkeley Lab researchers sometimes resort to unusual approaches to understand how energy is used and the opportunities to conserve. EETD's Alan Meier has been studying standby power use in appliances—i.e., the energy consumed when appliances are switched off or not performing their primary function. Almost all devices with remote controls (such as TVs, VCRs, and garage-door openers), soft keypads (microwave ovens), or rechargeable batteries (cordless phones) have standby power consumption. Meier estimates that almost 10 percent of the electricity used in California homes is now devoted to standby.

Meier expects that set-top boxes for TVs will be the next important appliance with standby power. These devices receive signals from a cable or satellite and feed them into the TVs. Because some include Internet access, digital hard disks, and other features, they are becoming increasingly complex. One of the curious aspects of set-top boxes is that they use nearly as much power when switched off as when switched on. To learn where the power is going, Meier used infrared photos to determine which components were energized in its various modes. The initial goal was to identify energized components that were not required or where more efficient ones could be substituted. Meier, along with graduate student Stefan Zandelin, photographed the units with an infrared camera. Energized components appeared as bright red objects. The researchers could then determine those component's functions

electricity consumption (13W) by components of a cable box in the 'on' position
electricity consumption (12W) when the box is 'off'.

Figures. The figure on the left shows electricity consumption (13W) by components of a cable box in the "on" position. The figure on the right shows the electricity consumption (12W) when the box is "off."

Meier found many cases where components (such as image-processing chips) were switched on, even when there was no possibility they would be needed. Since some of these chips consume lots of power, there was obvious potential for energy savings. He found that simple redesign of some set-top boxes could cut power consumption by as much as 90 percent without any reduction in services or features.

Investigating Standby Energy Use of New Internet Technology

Dale Sartor of the Applications Team (A-Team) recently upgraded the Internet connection on his home computer from a dial-up to a fast DSL modem. Noticing that the new modem was running hot to the touch, Dale contacted EETD's Alan Meier and Karen Rosen, who have been studying standby power loss in household appliances. They outfitted him with a watt meter and sent him back home. Sure enough, Dale found that his new equipment had bumped up his "standby"usage by 14 watts, which amounts to a 26% increase in load.

In the mode that many users leave their computer, (i.e., computer on, monitor off), the 67 watts of standby power (seen in Table 1) is about half of the total energy used when both the computer and monitor are on, connected at high speed to the Internet, and in print-ready mode (138 watts on Dale's PC).

The computer monitor remains the largest energy consumer for PC components. When Dale's 17" monitor is on, it consumes up to 60 watts. Many people also use a screen saver. Screen savers don't save energy. In fact, standby energy use of a personal computer with a screen saver almost doubles. On Dale's PC, it increases energy use to 122 watts (from 67 watts).

Fortunately Dale has an Energy Star™ compliant monitor which powers down into a "sleep"mode after a set length of inactivity. His monitor goes to sleep after 15 minutes and the standby losses are reduced to 67 watts (with only 2 watts going to the monitor). Many computers have this feature, but it is often disabled.

The DSL modem and router added 26% to Dale's standby power consumption. Karen Rosen reminds us that even switching "off"the computer may leave the power supply and some internal equipment components "on" (almost 7 watts in Dale's case). Alan Meier's recommendation: If you don't need continuous access, unplug the computer at the power strip to eliminate this waste.

Table 1. Power consumption of PC in standby mode (watts)
  Plugged in, but "off" Turned on, but not being used
DSL model 1.4 7.4
DSL router with firewall 2.7 6.5
Ink jet printer 2.4 7.7
17" monitor 0.7 2 (±1)1
Generic PC CPU 0 43 (±3)
Total standby power 7 67

1 Computer off or in ENERGY STAR "sleep mode."

—Karen H. Olson

Lab's Energy-Efficiency Research Benefits Shippers of Perishables

An inexpensive advanced insulating material developed by Berkeley Lab researchers has been licensed by San Diego startup Cargo Technology Inc. for use as a thermal packaging to ship perishable cargo such as seafood, meat, fruit, prepared foods, and pharmaceuticals.

The Cargo Technology product, AirLiner, is an inflatable insulating bag that converts an ordinary corrugated box into a cooler to keep perishables cold and fresh during shipping. AirLiner can be inflated with ordinary air or, to further enhance its thermal performance, with inert gases.

Cargo Technology says the markets for insulated packaging materials for shipping perishable cargo by air are growing and estimated at about $500 million annually. The company says that about 5.5 billion pounds of perishables are shipped by air without refrigeration annually in both the U.S. domestic and import/export markets in nearly 100 million containers.

Currently, most of these shipments are kept cold in expanded polystyrene foam containers. Polystyrene is a 30-year-old technology that is bulky, cumbersome, and prone to cracking and leaking.

AirLiner is produced from plastic films with internal baffles that inhibit heat transfer. AirLiner can be transported to shippers in flat packages, saving warehouse space and delivery expenses for shippers who use foam boxes. About 50 AirLiner bags fit into the same space now as one similarly sized foam container.

EETD researchers developed the gas-filled panels used in AirLiner back in the 1980s as a spin-off of research on superwindows. Superwindows are double- or triple-paned energy-efficient windows with infrared-reflective coatings and inert gases filling spaces between panes for extra insulation.

The gas-filled panel technology was developed and patented at Berkeley Lab and was extensively tested at Oak Ridge National Laboratory to confirm its insulating performance. Since then, these panels have been used as thermal insulation in a variety of applications, notably in prototype energy-efficient cars and appliances, and as a potential insulating material in buildings.

The honeycombed layers can be filled with air or gas to produce a superior insulating material.

Figure. The honeycombed layers can be filled with air or gas to produce a superior insulating material.

Gas-filled panels are made of multiple, honeycombed layers of thin, aluminized plastic filled with a gas, either air or an inert gas: argon, krypton, or xenon. The insulating value of the panel depends on which gas is used as a fill-it ranges from R-5 per inch (air-filled) to R-20 per inch (xenon-filled). By comparison fiberglass insulation for buildings is rated at about R-4 per inch. In 1991, gas-filled panels won the Grand Prize for Home Technology in Popular Science's "Best of What's New" awards.

"We are hopeful that this market success will motivate others in the building and appliance field to look again at this promising, high-performance insulation technology," says Stephen Selkowitz, Head of the Lab's Building Technologies Department.

Gas-filled panels web site


In the Spring 2000 issue of EETD News, an article in the Research Highlights section titled "Miscellaneous Electricity Usage Growing" inadvertently omitted EETD's Karen Rosen, primary author of several papers on the subject. The article states that the combined electricity usage of small appliances (TVs, VCRs, audio equipment, etc.) in the "miscellaneous" end-use category often approaches that of the refrigerator, which is typically considered the largest electricity-using appliance in the home. The article further states that most of this energy consumption occurs while these small appliances are not in use.

To put some figures to these assertions, research by EETD's Karen Rosen and Alan Meier has shown that consumer electronics use about one-third of the electricity in the "miscellaneous" end-use category, or about 10 percent of total residential electricity use. Energy used while these systems are not providing the main service for which they were designed adds up to 60 percent of this total, for about six percent of total residential energy use.

For more information, see Rosen, Karen B. and Alan K. Meier. "Energy Use of U.S. Consumer Electronics at the end of the 20th Century," LBNL-46212, in the Proceedings of the 2nd International Conference on Energy Efficiency in Household Appliances and Lighting. 27-29 September 2000, Naples, Italy: Association of Italian Energy Economics (Rome).

Karen Rosen

(510)486-5784; fax: (510)486-4673

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