Exhaust Fan Energy-Saving Strategies

April 18, 2013
1 p.m. – 2 p.m.
Eastern Daylight Time


There is a significant amount of unrealized energy savings available in our nation's research and teaching laboratories. A typical laboratory consumes up to 10 times the energy per square foot of an office building, while specialized laboratories can consume up to 100 times more energy. The ventilation system (the outside supply, conditioning, and exhaust) often uses up to 80 percent of this energy. Although supply air and conditioning systems account for approximately 60 percent of the ventilation system energy consumption, and have been the focus of laboratory designers for the past several decades, energy saving-strategies often overlook the exhaust system, even though it accounts for approximately 30 percent of the laboratory building's total energy consumption.

Traditionally, laboratories have been designed such that the exhaust system must operate at full load conditions 24 hours a day, 365 days a year—a constant volume (CV) exhaust. This design doesn't take into account the exhaust stream contaminant level nor the wind conditions for the fume reentry set point. Ron Petersen and Brad Cochran, of CPP, Inc., discussed strategies for a variable air volume (VAV) system that can be used, in part or in whole, during the design of a new laboratory or renovation of an existing laboratory to reduce the energy consumption of the exhaust system. Participants learned the different types and benefits of VAV exhaust systems.

Participants in this discussion learned:

  • Determine appropriate strategies for saving fan energy costs during design or renovation.
  • Identify which exhaust systems can provide the most energy savings.
  • Evaluate the benefit of using VAV with and without wind control.
  • Evaluate the benefit of using VAV with and without chemical monitoring.

Registration and Recording

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Professional Development Hours and Continuing Education Credits

Attendees of this course and those who view the recording can earn one Professional Development Hour (PDH) for professional engineers or one Learning Unit (LU) from the American Institute of Architects for registered architects.

Contact I2SL if you would like to receive a professional development credit for viewing the webinar.

Instructor Biographies

As a principal at CPP, Dr. Ron Petersen has led the exhaust dispersion group for more than 30 years, during which time the group has specified the exhaust parameters for more than 500 laboratories. More recently, Dr. Petersen has led the way in developing methods for minimizing fan energy costs while at the same time maintaining health and safety. Much of this development was carried out through ASHRAE- and CPP-funded research studies related to exhaust design.

Brad Cochran, is a Senior Associate at CPP with nearly 20 years of experience conducting wind-tunnel and numerical modeling studies related to laboratory exhaust design. Mr. Cochran has managed projects for such clients as Harvard, the National Institutes of Health, University of Texas Medical Center, Loyola University, Genentech, and the University of California, and several International Pharmaceutical manufacturers.

During the past decade, Mr. Cochran has focused on defining new design techniques to minimize the energy requirements for laboratory exhaust stacks. In 2005 Mr. Cochran developed the first laboratory exhaust system that utilized local wind data to minimize exhaust fan horsepower requirements, and in 2008 introduced the concept of monitoring chemical constituents within the exhaust manifold to reduce volume flow rates when the exhaust is essentially "clean." Both of these techniques are either in use or under development in laboratories across the country.

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