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Key Objective: 7. Fume Hoods Conversion from CAV to VAV

Convert all CAV fume hoods to variable air volume (VAV) systems with heat recovery.  

Convert all remaining Continuous Air Volume (CAV) fume hoods to Variable Air Volume (VAV) systems with heat recovery.

Associated Metric

No metric specified for this objective

Explanation

"Fume Hoods: The campus is estimated to have between 1,700 and 1,800 fume hoods in operation at the present time. The majority of these are constant air volume (CAV) hoods without heat recovery that operate continuously. Several hundred variable air volume (VAV) hoods also exist, which are in operation only when the hood sash is raised. These hoods, however, are often operated continuously. Based on a Trane TRACE energy model for a typical fume hood on campus, the cost of conditioning air to replace the air vented by a CAV fume hood over the course of a year is estimated to be approximately $5,500 per year. The energy model also predicts an energy usage for VAV hoods, CAV hoods using heat recovery, and VAV hoods using heat recovery to cost about $2,100, $3,200, and $1,500, respectively. Fewer than 200 of the campus’ 1,700 fume hoods are VAV. These figures provide an opportunity to significantly reduce fume hood energy consumption. If the campus takes into account some portion of fume hoods that utilize VAV or heat recovery, the University can conservatively assume the average cost of hood operation to be $3,750 per year. Using this average cost, the total energy cost that can be attributed to campus fume hoods is roughly 9 percent of the campus total. The University believes the physical number of fume hoods in operation can be reduced by 20 percent to 25 percent. This is based on the fact that many rooms have multiple hoods that do not require simultaneous use, and that many of these fume hoods are currently used for chemical storage and cannot be removed. The remaining fume hoods should all be converted to VAV systems with heat recovery—these can reduce a CAV hood's energy consumption by 70 percent. This strategy will also require an educational component. Groups and individuals will need to be educated on operating hoods correctly and to shut the hood sashes when not in use. The above actions can reduce campus energy consumption by at least 2 percent. Our new target for fume hoods is 2 percent."

Theme

Project History

  • 2/1/2017

    There were nine projects approved by the Revolving Loan Fund selection committee, see attached image.

  • 4/19/2014

    My information is a bit dated, but I had calculated $5.25/cfm for constant air versus $3.23/cfm for variable flow hoods.