<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi, Loïk. Welcome to the group.<div class=""><br class=""></div><div class="">I would caution you about neglecting the heat contribution of the cleanroom lighting and the fan filter units. Make sure they are really, truly, negligible, because it is not difficult for them to dominate the total cleanroom heat load under some conditions! In addition, we find that almost all of our equipment is in operation almost all of the time, so before you use the .75 diversity factor, make sure it is realistic.</div><div class=""><br class=""></div><div class="">The ACS has to be designed to meet the worst-case heat load, which will be worst-case weather conditions, plus everything turned on and running, plus maximum personnel heat load, under conditions of worst-case (maximum) makeup air flow. Getting all of this right is one of the most challenging problems in cleanroom design.</div><div class=""><br class=""></div><div class="">Good luck!</div><div class=""><br class=""></div><div class="">--Mike</div><div class=""><br class=""></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Mar 16, 2015, at 10:36 AM, Loïk GENCE <<a href="mailto:Loik.gence@cetuc.puc-rio.br" class="">Loik.gence@cetuc.puc-rio.br</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
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<div text="#000000" bgcolor="#FFFFFF" class="">
Hi Everyone,<br class="">
<br class="">
I am working on the design of a small cleanroom facility (70m2) ISO
5/6. Right now, I am dealing with the problem of thermal load,<br class="">
Which is crucial here in Rio, where the average outside temperature
is of 30 deg C with a relative humidity of 75-80 %.<br class="">
<br class="">
I would like to have your help and/or comments on several points:<br class="">
<br class="">
Most of the manufacturers do not provide a value for the thermal
load (why?). Assuming 2 or max 3 people working simultaneously in
the cleanrooms, and usual cleanroom value: 22 deg C - 55% humidity.
The main issue is: how can I estimate the cooling power required for
the Air Conditioning System (ACS)?<br class="">
<br class="">
I have the list of equipments we'll have and the corresponding
electrical power. I assumed the heat generated by 2 users and added
the total electrical power dissipated as heat inside of the
cleanroom, using a simultaneity factor of 0.75 (all equipments won't
be turned on at the same time) and neglected the heat produced by
the filter fan and lightning. <br class="">
<b class=""> </b><b class=""><br class="">
</b><b class=""> - Is it reasonable for dimensioning the ACS cooling
power ? </b><br class="">
<br class="">
Also most of the equipments have a cooling water circuit. But the
cooling power needed is well described in the installation manual
provided with the equipments. <br class="">
<br class="">
<b class=""> - Should I subtract from the </b><b class="">ACS cooling power</b><b class="">
value, </b><b class=""> the cooling po</b><b class="">wer </b><b class="">from the chillers?</b><br class="">
<br class="">
- <b class="">Do you think a central and unique chiller (placed
outside of the building) is preferred to several smaller chillers
placed closer to the equipment?</b><br class="">
<br class="">
<br class="">
I thank you very much for your kind help or comments.<br class="">
<br class="">
<br class="">
regards,<br class="">
<br class="">
Loïk.<br class="">
<br class="">
<pre class="moz-signature" cols="72">--
__________________________________________
Dr. Loïk Gence
PUC-RIO/CETUC-LABSEM
End Rua Marques de São Vicente, 225-Gavea
CEP:22451-900 Rio de Janeiro, RJ-Brasil
(Telefone) +55 (021) 3527-2193
(Mobile) +55 (021) 99156-5558
<a class="moz-txt-link-abbreviated" href="mailto:loik.gence@cetuc.puc-rio.br">loik.gence@cetuc.puc-rio.br</a>
__________________________________________</pre>
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