News From the Hood, Volume 1, March 2002
NOVEMBER Issue No.4 2 0 0 4

Brought to you by The Applications Team at Lawrence Berkeley National Laboratory.

Contact Info

Technical Questions:

Geoffrey C. Bell
gcbell@lbl.gov


Newsletter Feedback:

Evan Mills
emills@lbl.gov


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The Berkeley Hood
Applications Team
LBNL
EETD
Fumehood Picture
Laboratory fume hoods are highly energy-intensive pieces of equipment found across a spectrum of industries and in educational labs. Each hood uses as much energy as three average U.S. homes, and we estimate that existing fume hoods use up to half a billion dollars of energy each year. The Berkeley Hood project is working towards the commercialization of an alternative hood design that will cut energy use by 50% or more, while improving safety through enhanced containment of dangerous materials within the hood and reducing the size and first costs of facility HVAC systems thanks to lower overall airflow. This newsletter keeps readers abreast of new developments in research being conducted in this exciting area by the Lawrence Berkeley National Laboratory (LBNL) Applications Team.

New Industry Partnership with Genie Scientific  

In the latest phase of LBNL-Industry collaboration on commercialization of the Berkeley Hood, Genie Scientific, Inc. (Fountain Valley, California) is building three prototypes for use in demonstration projects sponsored by the California Energy Commission’s Public Interest Energy Research Program (PIER). Currently identified demonstration sites are the National Food Laboratory (Dublin, CA) and ChevronTexaco (Richmond, CA).  One more site within California is being sought (expressions of interest can be provided to Geoffrey Bell, gcbell@lbl.gov ).
 

Toe-to-Toe:
Berkeley Hood Outperforms Standard Fume Hoods

To ensure that Berkeley Hood containment performance is equal to, or better than traditional hoods, LBNL and CAL/OSHA have developed a protocol for dynamic side-by-side testing. 

As a first step, we conducted ASHRAE-110 static tracer-gas tests on six-foot-wide versions of a conventional hood and a Berkeley Hood.  To further test hood containment, we performed more demanding tests such as sash movement effect and a periphery traverse test (moving the detector instrument around perimeter sash opening).

We then extended the “challenge” to include a dynamic human-as-mannequin (HAM) tracer-gas test.  This HAM protocol, developed in collaboration with CAL/OSHA includes a choreographed sequence of 60 movements repeated three times for each hood.  The human subject wears a detector which measures a tracer gas in their breathing zone, while the subject manipulates objects in center, left, and right positions of the hood work area.

While testing the conventional hood per CAL/OSHA’s requirements, we observed typical variations in face velocity both for a given location in front of the hood, and as the test position is varied.  Going beyond the standard Cal-OSHA procedure, we also measured total exhaust to verify the face-velocity measurements.  We tested both hoods in all cases with the sash wide open (a worst-case configuration).

Importantly, both hoods passed the ASHRAE 110 tracer-gas tests (per the ANSI’s containment thresholds, click here for full report), both in as-manufactured (AI) and as-installed (AI) configurations.  However, results for the Berkeley Hood were consistently superior to those of the standard hood. Differences shown in the diagram below were statistically significant different between the two hoods as well as for the different test positions (center, left, and right).  Click here for a full report.


Laboratory Fume Hood Energy Calculator

Laboratory fume hoods are highly energy-intensive. The typical fume hood in US climates uses 3.5-times as much energy as a home.  We have launched a web-based calculator that estimates annual fume hood energy use and costs for user-specified climates and assumptions about operation and equipment efficiencies – Click here to start the calculator (or see http://fumehoodcalculator.lbl.gov/ ). 

The calculator can be used to test the energy and cost impacts of improving component efficiencies (e.g. fans or space conditioning equipment), modifying face velocities, and varying energy prices.  Supply air set points can be varied, as can the type of reheat energy.  Several hundred weather locations around the world are available.  The calculator allows for an instantaneous comparison of two scenarios.  More information on methodology can be found at http://eetd.lbl.gov/emills/PUBS/Fume_Hood_Energy.html