[BLDG-SIM] Variable flow laboratory exhaust systems.

JRR energy.wwind at cox.net
Thu Apr 14 06:24:39 PDT 2005


You have no option, the fume hoods have to run 24/7/365. In 1981 
University of Maryland College Park -- Chemistry Department had two grad 
students recrystalize an organic compound
using  warmed 100% N-Octane as the solvent. They wanted to speed things 
up so they
put the beaker in a regular refrigerator ......... The blast wiped out 
three lab rooms on the
4th floor. The frig did not have a sealed explosion proof defroster fan 
motor..........
The classrooms were empty and the two RAs got the munchies and went  the 
basement
vending machines for a candy bar, still the sight of their lab coats 
riddled with glass cuts.....

You can make the fume hoods a separate heating zone, supply them 
directly with heat exchanger
tempered outside air, and use two fan speeds occupied and vacant- hoods 
closed
john ross

Peter Summons wrote:

> OK , its Friday so I am allowed to ask for advice and guidance.
>
> Firstly I am using VisualDoe, I am modeling the energy performance of 
> a 200,000 sf building which has 60,000 sf of laboratories. The labs 
> all have fume hoods so the supply air is balanced to the exhaust air 
> (100% OA).. Now I have the following problem: a fan system is either 
> on or off, therefore the lab fans are on 24 hours a day. I would like 
> to reduce the exhaust flow during unoccupied periods to exhaust air 
> from the fume hoods at their minimum flow of 40%. Reducing the flow 
> would also reduce the make up of outside air to balance the flow and 
> obviously reduce energy consumption.
>
> Am I missing something here or does anyone have a magic trick that 
> will allow me to accomplish my goal. Simply said HELP
>
> Peter Simmonds Ph.D.
>
> Associate
> IBE Consulting Engineers
>
> 14130 Riverside Drive Suite 201
>
> Sherman Oaks, CA 91423
> p:   (818) 377-8220
> f:    (818) 377-8230
> m:  (818) 219-1284
> IDEAS FOR THE BUILT ENVIRONMENT <BLOCKED::http://www.ibece.com/>
>
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