Chimney Effect for enclosure cooling!!

[TRWMark]

Hi every one.
We have hit a bit of a problem. We are designing an enclosure that is getting a tad warm. The max ambient temperature that the enclosure will be working at is +50C. At present the temperature rise is about 65-70C, this would give an operating temp of 115-120C. We do need to get this temperature down because this enclosure will be operated in an inhabited area!
Looking at the advice that was give to a guy whose temp rise was only 5C, we are going to try forced air convection, but am a bit concerned that we can tap into a air supply. I presume that the louvre area will have to be calculated based on the volume of air flow. The amount of area available for louvre fitting is very limited!!

Is there any other way that we could cool be integrating a combination of chimney effect cooling and forced air?

Another idea that we had was to paint the inside black!! In anyones experience, is this any good?

Please help.
(PS the enclosure is made out of 1.2mm thick aluminium!!)

 

[prodeng]

If you have louvres on the bottom and either the top or upper sides, you will draw from the bottom creating some additional stack effect. You could also try to create a venturi effect, though you may not get the air to cool where you want it that way.

I would not paint the inside black. Not knowing the specifics of what is inside the enclosure, that may only make the problem worse. Black would absorb the radiant heat much more, and then dissipate it to the outer surface. A type of insulation on the inside surface with cooling air would probably be your best bet. There are some pretty good insulators that are thin-walled. Hope this helps.

 

[RicAdamson]

Don't know what resources you have available or space constraints. If you have access to compressed air, then a venturi cooler will work great. Also don't have a feeling for scale (1kW? 10kW? 100kW? 1MW?)

There are also Peltier effect coolers that can be used to pump heat through the wall. Although these consume power, they can create substantial delta-T across the housing wall without punching holes. R Adamson
VP Engineering
Mariah Energy Corp.