air pressure

papasmurf

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I wonder what the effects of having a higher or lower air pressure does to temperatures. perhaps if we could find a way to raise the air pressure the heat would better be conducted, has anyone had any experiances with say a realy high elevation compared to a realy low one?


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cakecake

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Not sure what you mean. More CFM's are always better?

I've found that surface area that contacts air is important. Mainly it's because air is circulating all the time. If you cup your hand around your ear you can hear air circulating. Without this everything would overheat way too easily as any air molecules nearby a heat producing component would simply stay put and heat up and eventually bake the components around it. If you encapsulate something so that it has absolutely no way for air to travel in and out, then you are doing the same thing as getting rid of surface area, and that's bad for your components if it gets out of hand.

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papasmurf

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so your theory is that the lower the air pressure, the more the air can circulate therefore the more cfm's and heat dissipitated, I would immagine this is the case, however perhaps compressing air allows for better absorbtion of heat,I need to test this, also air content may be a factor, I read somewhere (not sure if it is true) that water itself can not conduct electricity very well, the tiny mollecules inside floating around do, it is probably not true, but the idea still applies cleaner air may also conduct heat better, the idea of this post is to try to figure out how to get the most out of air cooling, perhaps there is a better way than just blasting the air at something, or perhaps the things mentioned would make little or no difference.

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Bardic

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In an open system to try to make the air hit the heatsink surface harder you would have to restrict some of the air out from the HS and increase the size of the fan so you still have the same amount of airflow. Otherwise it would just be more CFM which we already know helps.

If you construct a doughnut shaped tube, air tight, with a heatsink and a fan circulating the air around the loop, then you could pump up the preasure, or decrease the preasure for testing. But you would have to have some way to cool the air before it came back around.

Would elevation be enough difference to test? You would probably want to use the same computer with the same case temp at the 2 elevations.
 

cakecake

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Yes, it's true water itself doesn't conduct electricity. There are particles in water that give the water a pH +/- of 7, causing it to be ionic and therefore conductive. If you pour distilled water into a running computer it may stop the computer from working but once dried up it may still run fine. Curious isn't it?

Fluorinert is a liquid made by 3M that costs about $500 per gallon. It's completely nonconductive and you can soak your computer components in it. It's a curious idea although I have no clue how you could cool the fluorinert itself once it heats up.

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zigzag

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Actually, I was not referring to the conductive properties of water, rather that more humid air will hold heat longer and therefore, in that expirement, you would need to make sure the humidities of the environments surrounding the two machines were identical. Though you do make a good point cakecake, if you raise the pressure substantially and there is too much water in the air, it could condense and cause electrical problems.

-zigzag