Enclosed space cooling

[corus]

I wish to cool an enclosed space by insertimg holes into the outside surfaces to allow air to flow through. How big should the holes be (and how many), before I can assume that natural convection to an ambient outside temperature occurs?

corus

 

[quark]

What is the total room heat load? Or, the dimension of the room, No. of people working, No. of lights, Equipment wattage, any exposed walls etc. Do you wish the air to flow by natural convection?

Regards,

 

[corus]

It's not a room but a steel container that has a heat source on one side. The question is general as I want to know of the correct method to use to evaluate this or of empirical data that can be perhaps extrapolated to fit these circumstances.
To rephrase the question, what size openings do you need relative to the size of the container so that sufficient flow occurs for natural convection to ambient to be assumed on the internal surfaces, approximately? Radiation to ambient would obviously be partially blocked and can be evaluated.

corus

 

[MintJulep]

Essentially, as the air temperature inside the container increases the density of the air decreases. When the bouyency difference inside to outside is sufficient to overcome the pressure drop across the holes, convective flow will start. The flow rate will tend to balance itself, as resistance increases with flow rate.

Search the archives here for stack draft or chimney effect.

It is impossible for natural convection to ever cause the temperature inside to equal the temperature outside.