[labnetwork] Thermal load in cleanrooms ISO 5/6

[Iulian Codreanu]

Loik,

Another thing to keep in mind is the heat that is "taken away from the 
equipment" via exhaust.

The heat generated by a piece of equipment can:
-Be dissipated into the room
-Be "taken away" by the cooling water.
-Be "taken way" by exhaust.

If a piece of equipment is not cooled and does not have exhaust then all 
the heat gets dissipated into the room.

If the piece of equipment is cooled and exhausted only part of the heat 
generated will end up in the room.

If you know how much heat is taken away by the cooling water and/or 
exhaust that is great.  If you do not, I saw engineers using factor such 
as (PCW stands for process cooling water):
100% of the power into  the room if no PCW and no exhaust
50% of the power into  the room is no PCW but exhaust
40% of the power into  the room if PCW but no exhaust
20% of the power into  the room if both PCW and exhaust

I prefer the "unique chiller (placed outside of the building)" approach 
for cooling the equipment.  If you can run the water from the unique 
chiller directly through the equipment, you do not have to deal with the 
heat generated by the "small chillers".

Iulian



iulian Codreanu, Ph.D.
Director of Operations, UD NanoFab
163 ISE Lab
221 Academy Street
Newark, DE 19716
302-831-2784
http://udnf.udel.edu

On 3/16/2015 10:36 AM, Loïk GENCE wrote:
> Hi Everyone,
>
> 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,
> Which is crucial here in Rio, where the average outside temperature is 
> of 30 deg C with a relative humidity of  75-80 %.
>
> I would like to have your help and/or comments on several points:
>
> 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)?
>
> 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.
> ***
> **        - Is it reasonable for dimensioning the ACS cooling power ? *
>
> 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.
>
> *        - Should I subtract from the **ACS cooling power**value, 
> **the cooling po**wer **from the chillers?*
>
>         - *Do you think a central and unique chiller (placed outside 
> of the building) is preferred to several smaller chillers placed 
> closer to the equipment?*
>
>
> I thank you very much for your kind help or comments.
>
>
> regards,
>
> Loïk.
>
> -- 
> __________________________________________
> Dr. Loïk Gence
>
> PUC-RIO/CETUC-LABSEM
>
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>
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>
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>
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