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How Does Humidity Affect a CPU temp

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May 21, 2001
because this just accured to me,
san diego (being right next to the ocean) is always humid (70%+ year round) does this mean that the tiny water particles help cool the HSF which allows it to run cooler? because ive never had any heat issues with my CPUs
I believe that the higer humidity does allow it to cool the hsf, because the water vapor invreases the heat capacity of the air, therefore allowing it to cool more. However, humid air is more dense and flow less, so you may not be getting the rated cfm from your fan. A detailed analysis would need to be done to see how the two offset eachother.
I'm in Louisiana where we also stay extremely humid all year long....but it also stays extremely hot here all year long. If anything i think humidity increases temp and decreases life of components. Moisture is bad for electronic components of any kind.
yes i know, but its not hot here in san diego, so its cool and humid so i was thinking maybe that could help me with cooling

and all eletronics are waterproof TO SOME DEGREE (proof is that there is always or almost always tiny water particles in the atomosphere)
Essentially theres not much you can do about humidity...it may help with cooling in the right weather conditions

also may increase temps b/c low boiling point of water may bring moisture to the temp of the surface it makes contact with

just a theory...would make an interesting study though...if you could do it without frying any components :)
i dont think humidity affects boiling temps
and processor doesnt get hot enough to produce boiling temps
AmbientFiction (Jul 30, 2001 11:49 p.m.):
Their is something to do about thier is a fluid that 3m makes its about $500 a drum non conductive liquid you can dunk your board in it and turn that sucker on without problems

whachutalkinbout willis?
Just checked from my psychrometric chart (@ 1atm): Density of air at 25'C, 10% relative humidity is 0.847m3/kg while at 25'C, 70% humidity it's 0.864m3/kg (1.18kg/m3 vs. 1.16kg/m3). Since the power to move fluid for fans at a constant speed is directly proportional to fluid density, (P=Cp*(density)*D5*n3), there won't be much difference in effort in the part of the fan to move more humid air. In terms of sensible energy, the enthalpy difference of 10% humidity air from 25'C to 30'C is 8 kJ/kg while for 70% humidity air it is 17 kJ/kg for the same +5'C increase. That's a whopping 113% increase in specific heat capacity!
Eh, BUT usually the most humid air is also the warmest air (warm air has bigger capacity for moisture), like in the tropics where I live. The really cool humid air would be from a building HVAC that both cools the air and humidifies it for the occupants' comfort. Unless you live in a well-maintained apartment or spend lots of time in a office block, then you won't be getting such 'good quality' air.
cjtune (Jul 31, 2001 02:03 a.m.):
That's a whopping 113% increase in specific heat capacity!

You've got the numbers. I was just going to mention that this is something you hear about in climate and weather. Temperature changes are more drastic in dry than wet climates, evidently because water vapor stores so much heat. Weathermen sometimes mention that high humidtiy keeps night temperatures from dropping much, so on the muggiest days you get the least temp drop at night.

It is the high heat capacity of water that makes it more effective for cooling than air, is it not?

In effect water stays at lower temp for a given uptake of heat, and so keeps the temp difference larger, impoving heat tranfer.
hmm, most interesting... If one could bring highly humid air or even steam to the heatsink, it could then take energy while vaporizing.

Enter mad cooling ideas:

Closed aircooled system. Has small water reservoir with heater to vaporize (humidify?) the air, radiator to cool the humid air, and some sort of ducting to take the air through the HSF. Certainly not better than water cooling, but more safer if leaking...
I think if you heat up water to make it evaporate, the heat is still in the water when it hits the cpu. You could try it if you can make water evaporate without heating it up first. That way you may achieve some temp difference. Also make sure you don fry your parts with condensed water dripping of the heatsink. If anyone is actualy mad enough to try it, I would really like to read about it here. :D

I don't know this for sure though, but it seems logical to me, and it is kinda backupped by my fysics lessons from the past years. :)
Endeavor (Jul 30, 2001 11:53 p.m.):
AmbientFiction (Jul 30, 2001 11:49 p.m.):
Their is something to do about thier is a fluid that 3m makes its about $500 a drum non conductive liquid you can dunk your board in it and turn that sucker on without problems

whachutalkinbout willis?

I think AmbientFiction is talking about Fluorinert. He's right! Its non-conductive and you can submerge the whole dang motherboard in their with no problems. Check out the link!


I wouldn't call him crazy! But the guy on that site is really out there. Couldn't believe it till I seen it!
Remember fellas, it's cool, humid air you want. It's also next to impossible to get totally dehumidified air unless you live in the poles or with the aid of some dehumifying equipment. Evaporated water will only release latent heat when it condenses onto some surface but usually this is achievable only when you forcibly cool the air until it hits a satured humidity level (100% relative humidity, cold air holds, relatively, less water vapour but the amount of water vapour held is still the same), in effect taking away the latent heat.