Air Conditioner unit for enclosure

[utimgr]

I have a project where the box has a small AB PLC and a user interface panel, around a 20x20x8 NEMA4 enclosure.

So the customer wants a AC unit to keep the unit cool...so who makes small AC units to mount on the side? I am thinking heat exchanger or the like and I think most the heat will be convected heat into the box from the New Mexico sun. I cant just use fans to move the air but need a coolor.

 

[jraef]

A heat exchanger will only work if there is a 10 degree delta between the inside and outside of the box. In your case, it will likely pump heat IN to the box!

Look for thermoelectric (Peltier Effect) air conditioners, they are sometime smaller than compressor types for light heat loads. Something like this.

http://www.thermoelectric.com/2005/pr/ssac/fhp-450xe.htm

Eng-Tips: Help for your job, not for your homework Read faq731-376

 

[utimgr]

Excellent...I hadn't thought that it might drive heat into it.

These thermoelectric units basically remove heat from the box by using the Peltier plates, so as long as the interior of the box remains below the setpoint, the unit remains off..correct?

So what about using a fiberglass box (my preferene actually) vs a steel...should make NO differene to the unit, but the convection of heat into the box should be reduced?

 

[itsmoked]

Also you MUST (that's absolutely) shade the box. Direct sunlight is death to electronics. Especially PLC type stuff.

The shade should be included in the design from the very start. Don't leave it as an "oh yeah" item at the end. I would agree with a non-mechanical cooling system. Make sure you have an efficient power supply as you can essentially throw away cooling capacity, directly, by using a crummy PS.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[jraef]

Non-metallic boxes are fine when cooling is used, but their thermal transfer rates are slower so they are not as good when you are trying to avoid having to use an external cooling unit. Fiberglass is also problematic when you use compressor type A/C units because the vibration they create wears the mounting holes oblong and eventually the box integrity fails. Thermoelectric coolers have no moving parts, ergo no vibration. So yes, fiberglass would be fine in that case.

I'll add my voice to Keith's: shade shade shade.

Eng-Tips: Help for your job, not for your homework Read faq731-376

 

[N1PIY]

utimgr,
I use a small AC units which are mounted on the outside of control cabinets for my CNC routers. They work very well at keeping the internal mounted control drives at normal operating temperatures. Check out this site for details.

http://www.mcleanthermal.com

Good luck stay cool.
N1PIY