Laboratory buildings are very energy intense. Laboratory buildings use energy for technical equipment, lighting, heating and cooling. They also use significant energy to heat or cool air to make up for air that is exhausted. Fume hoods are a major factor in facility design and energy use, influencing exhaust capacity, duct size, fan power requirements, boiler size and chiller capacity.
Providing a safe environment for all personnel is the primary objective in the design of HVAC systems for laboratories. Fume hoods require high exhaust air flows, which leads to higher outside air flows than those required by the occupants. Therefore, the energy needed to condition and transport the air supply is often determined by the fume hoods, rather than occupant considerations. In order to reduce the energy needs of laboratories, either the exhaust air flow for fume hoods must be reduced or the fume hoods have to be supplied with auxiliary air not being conditioned.
The reduction of exhaust air, if no counter-measures are taken, leads to lower face velocity, which increases the risk of spilling pollutants from the fume hood to the laboratory.
While the performance of a conventional hood depends on an even air flow distribution of air flow in the face of the hood, the energy efficient fume hood proposed here works on the principle of low flow displacement ventilation. This concept was tested in hospital operating theaters. A tube made of porous material was pressurized with filtered outside air; if the tube was placed around a patient’s wound, no airborne particles would enter the protective space created by the displacement ventilation provided by the tube (Esdorn et al 1977).
A similar principle is used for protecting the face of a fume hood. Instead of using a tube, we designed a frame which encloses the face. Air at low velocity and low turbulent intensity is supplied towards the center of the face. At the air outlet, flow is perpendicular to the air flow found in conventional hoods. The supply air flow (NOT auxiliary air flow!) builds a protective buffer zone between the volume of the hood and the laboratory space. With this flow direction, face velocity does not have meaning anymore!
Co-founded by Helmut Feustel and Geoffrey Bell, in conjunction with Chris Buchanan, William Fisk, Darryl Dickerhoff, and Doug Sullivan, the new fume hood uses only 30 percent of the airflow of standard laboratory fume hoods. This could result in a downsizing of building HVAC systems, saving energy and construction costs. Dale Sartor, of LBL Environmental Energy Technologies Division's Applications Team, estimates that 360 gigawatt-hours could be saved per year in California alone.
ATMI Inc. has also signed an agreement to develop a version of the containment technology for use in semiconductor manufacturing facilities.
The new fume hood has passed standard tests and Fisher Hamilton Inc. is currently building units for testing and demonstration at Montana State University's EPICenter Project, an environmentally friendly 21st century academic laboratory. Berkeley Lab is one of MSU's partners in the design phase of this project.
The technology was shown at the Laboratories for the 21st Century Conference in September 2000 in San Francisco.
Last Modified: June 27, 2000