[labnetwork] Thermal load in cleanrooms ISO 5/6

[Mike Young]

Hi, Loïk. Welcome to the group.

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.

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.

Good luck!

--Mike


> On Mar 16, 2015, at 10:36 AM, Loïk GENCE <Loik.gence at cetuc.puc-rio.br> 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 power 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      
> 
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> 
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-- 
Michael P. Young                                (574) 631-3268 (office)
Nanofabrication Specialist                      (574) 631-4393 (fax)
Department of Electrical Engineering            (765) 637-6302 (cell)
University of Notre Dame                         mike.young at nd.edu
B-38 Stinson-Remick Hall
Notre Dame, IN 46556-5637

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