Energy and Cost Savings from Advanced Exhaust Dispersion Testing

Chet Wisner, Ambient Air Technologies, LLC

Substantial energy and cost savings are possible when using advanced exhaust plume dispersion modeling to support the design of laboratory exhaust systems. The design of renovated exhaust systems on existing laboratories as well as designs for new laboratories can benefit.

This presentation reports on the savings for a typical modern laboratory design and on the savings for the renovation of a laboratory exhaust system common for those built in the 1970s and 1980s. The reported savings are based on wind tunnel testing of a typical laboratory in a representative campus setting. For the new laboratory, the design, optimized using wind tunnel testing, is compared to a design based on the simple methodology recommended in Chapter 44 of the ASHRAE Fundamentals Handbook. For the renovation design, the new design is compared to the typical 1970s/1980s system. The exhaust system designs restrict the maximum normalized pollutant concentrations to the design criteria recommended by ASHRAE for laboratories. The study focuses on the use of simple design alternatives (e.g., stack height, stack location, exit velocity, intake location) which are commonly available to the design team, but also shows the advantages of some less commonly used design elements such as roof configuration. Examples from actual projects will also be presented.

This presentation focuses on the impact of exhaust system design on the Labs21 principles of minimizing energy impacts and optimizing building efficiency while ensuring the health and safety of laboratory workers and neighbors.

Biography:

Chet Wisner is the president of Ambient Air Technologies, LLC, a Colorado-based firm specializing in wind tunnel modeling of laboratory and healthcare facilities. He has played an active role in the air quality portion of the environmental industry for over 35 years. Applying his experience and expertise in meteorology, engineering, and physics to physical modeling using scale models in a boundary-layer wind tunnel, he has personally managed or directed many wind tunnel studies. Chet coauthored an EPA-recommended protocol for the use of environmental wind tunnel studies to determine plume downwash characteristics for input to EPA's own regulatory dispersion models. He was responsible for some of the largest air quality monitoring networks in the United States, and has conducted numerous field studies of atmospheric dispersion. His educational background includes a Bachelor of Science in engineering physics from the University of California at Berkeley, a Master of Science in meteorology from the South Dakota School of Mines and Technology, and a Master of Business Administration from the University of California at Los Angeles. He is an active member of several professional organizations including ASHRAE, the Air and Waste Management Association, and the American Meteorological Society.

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