Clean Room Equipment Suggestions??

[BronYrAur]

Any recommendations on a manufacturer or type of equipment for a clean room? I am probably in the 2000-3000 CFM range, of which anywhere from 30% to 100% may be outside air based on hood usage. Location is near Chicago. They want to maintain 68 deg F +/- 1 deg and 45% RH +/- 5%. I'm still kicking around chilled water versus DX and hot water vs electric heat. I will probably need an ultrasonic humidifier for winter.

Any recommended manufacturers, especially one who can really help out with the equipment selection?

 

[nuhvac]

Engineered Air, has UV lights, Ozone plates for oder control, sales men will help you out alot with equipment selection, units can be built all stainless steel with washdown construction. The equipment is all 100% custom so whatever you can think up they can do. They have a sales office in chicago, you can check them out at

http://www.engineeredair.com

 

[BronYrAur]

One other thing, the customer is very concerned with energy efficiency. the hood in the room will have VFD's and they would like to utilize as many energy savings techniques as possible.

 

[nuhvac]

Heat pipe would be a good way to go. No cross contamination and good energy recovery. I would suggest giving the chicago office a call and see what they can do for you.

 

[AbbyNormal]

You will probably be changing the air 20 times in there as a minimum.

You need to know how clean you have to maintain the space, the class

I did a lab unit back in the day when I worked for EngA. Over cool the air to get that dewpoint you want, reheat it with discharge air control (reset) to keep the space at whatever temperature you wanted. We had a fancy dri-steem humidifier in it for winter time.



Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[nuhvac]

Haha you worked for EngA? Thats who I currently work for. Good company with a solid product I believe.

 

[Zesti]

Maybe a rotary heat exchanger (

http://www.klingenburg.de/en/products/rotors.html)

then you also get part of your moisture back so you don't need to humidify as much.

And of course as much recirculated air as you can get.

Why the ultrasonic humidifier? Why not go for steam?

 

[nuhvac]

Zesti, in this application a rotary heat exchanger will have partial contamination carry over, this a bad thing if the exhaust has chemicals and odors you are trying to get out of the room.

 

[Zesti]

I think it is negligible if you are having a cleanroom at over 20 ACH and 100% outside air.

The contaminants are already inside the cleanroom and all the AC does is dilute and extract. The small carry over should be of no influence.

Besides, if you place your fans right there won't be any carry over as there will be positive pressure from the clean air side to the extraction air side of the rotary exchanger.

 

[nuhvac]

Not saying you are wrong, just disagreeing. We as a rule dont use wheels when exhausting anything with contaminants in it. To us the idea of having a 100% OA air unit is to have "clean" air coming in. The idea, to me, to use 100% OA here is because you are trying to exhaust air you dont want in your supply. Yes you can set up your fans for minimal carry over, but we have tested this and we know that regardless of your purge angle there will be some carryover. I guess I just would think it would be just as good of an idea to use a heat pipe. It will transfer just as much energy in the summer and winter (with a tilt feature). The amount of humidity you will gain from the wheel wont amount to much anyway.

 

[AbbyNormal]

Renewaire has cross floor cores that recover some moisture, no moving parts.



Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[AbbyNormal]

make that cross flow

Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[Zesti]

I agree, there will be carry over.

I am not very familiar with heat pipes so I don't know how their thermal efficiency compares to a rotary exchanger.

If the customer is after as much energy-saving as he can get then I still think a rotary exchanger is worth a look. Seems to me there is a saving to be made on humidifying the cold and dry winter air. And when you have high outside humidity in summer, getting rid of a bit of moisture will also cut down on the cooling load.

As for the carry over: if at 20+ ACH of 100% outside air ,with a minimal fraction of carry over, there are still doubts about the indoor airquality, wouldn't it be time to think about putting the workers in suits with fresh air supply to the suit?

What I mean is, I feel the "carry over issue" is often more about psychology than anything else...

 

[nuhvac]

Yeah I do not disagree with that logic at all Zesti! But we are talking about a clean room, so actually even though you probably meant it as a joke, the workers ARE in suits which is why I think even the mention of the possibility of carry over to the engineer would make him freak out. Heat pipes are pretty good at energy recovery about 84%, and depending on the outdoor and supply temperatures they are looking for sometimes a wrap around heat pipe is even better. It lowers your mechanical cooling load by precooling the air and then reheating it all free of charge since it is a closed system.

 

[nuhvac]

One other thing, i dont think conserving the amount of humidification needed is really a concern. This is in Houston! I mean if you can run fast enough and jump, you can swim through the air!!!