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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<br>
using warmed 100% N-Octane as the solvent. They wanted to speed things
up so they<br>
put the beaker in a regular refrigerator ......... The blast wiped out
three lab rooms on the<br>
4th floor. The frig did not have a sealed explosion proof defroster fan
motor..........<br>
The classrooms were empty and the two RAs got the munchies and went
the basement<br>
vending machines for a candy bar, still the sight of their lab coats
riddled with glass cuts.....<br>
<br>
You can make the fume hoods a separate heating zone, supply them
directly with heat exchanger<br>
tempered outside air, and use two fan speeds occupied and vacant- hoods
closed<br>
john ross<br>
<br>
Peter Summons wrote:<br>
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<p class="MsoNormal"><font size="2" face="Arial"><span
style="font-size: 10pt; font-family: Arial;">OK , its Friday so I am
allowed to ask for advice and
guidance.<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Arial"><span
style="font-size: 10pt; font-family: Arial;">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.<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Arial"><span
style="font-size: 10pt; font-family: Arial;">Am I missing something
here or does anyone have a magic
trick that will allow me to accomplish my goal. Simply said HELP</span></font></p>
<p class="MsoNormal"><font size="3" face="Arial"><span
style="font-size: 12pt; font-family: Arial;">Peter Simmonds Ph.D.</span></font><o:p></o:p></p>
<p class="MsoNormal"><font size="3" face="Arial"><span
style="font-size: 12pt; font-family: Arial;">Associate</span></font><br>
<font size="1" color="gray" face="Arial"><span
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Consulting Engineers</span></font><o:p></o:p></p>
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style="font-size: 7.5pt; font-family: Arial; color: gray;"> Oaks, CA
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p: (818) 377-8220<br>
f: (818) 377-8230<br>
m: (818) 219-1284<br>
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