Low-Energy Fume Hoods to Reduce Operation Costs

Fume hood operation may soon be significantly less expensive because of a new design developed at Lawrence Berkeley National Laboratories.

The new design, which requires a smaller amount of air to circulate within the hood than forms currently in use, is slated to undergo testing at an advanced laboratory facility at Montana State University at Bozeman.

The newly designed fume hood uses approximately one-third of the air circulated in currently used models, according to Geoffrey Bell, a researcher at the laboratory's Environmental Energy Technologies Division.

Reducing the amount of air in the hood could reduce the costs of operating the machines by approximately $30 million a year in California alone, Bell said. If installed nationally, the scientists estimate that the fume hoods could result in energy savings of $300 million.

Fume hoods, which are box-like structures designed to protect scientists from fumes emitted by toxic chemicals, are used in industrial, medical and university research facilities.

The average hood is 6 feet wide and 2 to 3 feet high, circulating air at a rate of approximately 100 feet per minute. Because the hoods often operate around the clock and require large fans, energy costs associated with running the hoods are high.

Current fume hoods use a large fan that moves air within the hood. This fan is located at the back of the machine, requiring a large amount of energy to move air.

"In the back of the box, there is a round duct where air is sucked out of the fume hood," Bell said. "It works like a chimney with a mechanical fan."

Because chemicals contained within the hood are often extremely toxic, a large quantity of air is required to keep the air surrounding scientists safe.

"To draw these fumes that are going to be created in flasks, you have to move a lot of air," Bell said. "Consequently, it takes a lot of energy to move that air."

The new fume hoods work by using a fan at the bottom of the hood's face and another fan at the top of the hood. This creates a push-pull system within the hood and also creates a wall between scientists and the toxic chemicals.

This technology employs a small fan and greatly reduces the amount of energy required to run the hood, Bell said.

"With our situation, we are introducing positive airflow to assist and to provide a cushion of clean air. This creates a divider," Bell said. "It is a lot more effective to put out a candle by blowing on it than by sucking on it."

The new hoods not only reduce the amount of air needed to operate the system, but also blow clean air into the face of the user, a feature that could increase worker safety, Bell said.

In addition, the new hoods are more environmentally friendly than the older models - normally, contaminated air gets dumped into the atmosphere to be diluted to a concentration no longer dangerous to humans. The new system dumps fewer toxins into the environment.

Because of the energy efficiency of the new hoods, they could be installed in all laboratories that require the machines. Laboratories could refit existing hoods with the new technology or install entirely new fume hoods.

"The new fume hoods will offer such substantial savings that scientists could replace the whole system and still save," Bell said.

The private sector has already begun to express interest in the new hood design, said researcher Dale Sartor in a statement.

"ATMI Inc. has signed an agreement with Berkeley Lab to develop a version of the fume-containment technology appropriate for semiconductor manufacturing facilities," Sartor said. "The technology has the potential to reduce operating costs and increase chip fabrication yield."

The scientists who developed the new technology have applied for a patent for the low-energy fume hood.

Tags: