Weekly Subject 03 - Cooling

Went looking for this, so copy/paste. cooling sites from the Langalist I got several months ago.
Sure a passel of them. http://www.3dfxcool.com/ http://www.pcpowercooling.com/home.htm http://www.heatsinkfactory.com/ http://www.inflowdirect.com/ http://www.coolerguys.com/ http://www.overclockin.com/ http://www.ocworkbench.com/ http://www.overclockers.com/ http://www.hardocp.com/ http://www.overclockershideout.com/ http://www.athlonoc.com/ http://bxboards.com/

If you are overheated Try this KOOOLLLL!

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Good Morning World, Oh me. More reading. Be in and out today. https://discussions.virtualdr.com/

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Hi all

DrMDj just about made a summarisation.
https://discussions.virtualdr.com/ COOL https://discussions.virtualdr.com/

He even mentions power supply fans don't always blow out.
And yes, once upon a time I mentioned rebadged CPU.
I too heard this practice still exists.
(sometimes they even advertise them as overclocked... in that teeny weeny small font and low contrast, but it happens, and I actually came across a few such adverts.)

in one of the tips I saved I read about the power consumption of a single CPU.
well, I was surprised when I found out how many watts it has to dissipate.

there is a lot left to research.
power consumption of various brands and types of CPU, graphics cards, motherboard (or the mobo chipsets),
different speed hard drives,
burners,

one could say, if you need a 400W power supply unit (aka PSU), you gonna have to get rid of 400W of heat...
how true would this be?
anyone know how many cubic feet of air one has to expell when one has to dissipate 300W, and ambient is 23C, and acceptable exhaust is 35C ?
I bet that's ever harder in british thermal units, and fahrenheit.
it can get complicated.
watt and joulle and calori confuse even me

also note I already used cubic FEET/m
we should talk of cubic meter nominal to stay in the metric system.

an example
to increase temp of one gramme of water with one centigrade, one uses 1 calori
(If I recall correct, to evaporate it takes 570 calori)

I also believe one cubic meter of air at nominal has a mass of around 80 grammes

I don't say these numbers are correct.
anyone interested in a science project?
well, tackle this one.


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You help someone with a similar problem if you tell us what worked.
When you do, please post solution in the original thread?
Kind regards, Jaak

Sounds like a good project jaak. But, not mine https://discussions.virtualdr.com/

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no kidding?
didn't trains run on steam?
and gosh, Charles WATT invented them
no wonder they went electric... https://discussions.virtualdr.com/


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You help someone with a similar problem if you tell us what worked.
When you do, please post solution in the original thread?
Kind regards, Jaak

jaak
my name sake http://www.neumedia.net/~cassrr/graphics/num_6a.jpg

More here

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[This message has been edited by Train (edited 06-10-2001).]

ahh,
don't let my unscientifically construed suggestion for a research project "derail" this "thread".

https://discussions.virtualdr.com/

...and I'm working on developing a quantum computer made from sugar water and baling wire. Think I have a clear idea on how to do it.
Uh....by the way...what's a "watt"?

Watts on second Bistro. Who's on first.

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Ya'all have gone over the edge. Just not sure which one. https://discussions.virtualdr.com/ https://discussions.virtualdr.com/

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Good Morning All, There was a wealth of information contributed on the subject of cooling in the past few days. For those of you reading and have a question or two about any part or a question about a problem you may have, ask away.

Does anyone see anything we have missed on cooling?

Should we need to keep going on this subject, I will start a part two tonight.

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Quote:

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Originally posted by greengoose1:
Should we need to keep going on this subject, I will start a part two tonight.

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I think that is enough about cooling, look forward to next discussion.

Well...I was gonna cover how to make a real neato case out of a Frigidaire deep freezer, but yeah...that about covers cooling for now.
https://discussions.virtualdr.com/

science is wonderful
and wonderfully simple in its complexity
and extremely complex in its research of wonders.

anyway
been looking for something about printed circuit boards (aka PCB)
http://www.mayahtt.com/tmwiz/convect/forced/pcb/pcb.htm

and I said something about the mass of air, and how much air would need to be moved thru the case to stay within a acceptable limit of increased air temperature.
Air at room temp will always contain water vapour.
To increase its temp takes more energy than it would for dry air.
Dry air is heavier than damp air at same temp .

Exerpt from "Thermal properties of damp air"
The heat content, usually called the enthalpy, of air rises with increasing water content.
The enthalpy of dry air is not known. Air at zero degrees celsius is defined to have zero enthalpy. The enthalpy, in kJ/kg, at any temperature, t, between 0 and 60C is approximately:

h = 1.007t - 0.026 below zero: h = 1.005t

The enthalpy of liquid water is also defined to be zero at zero degrees celsius. To turn liquid water to vapour at the same temperature requires a very considerable amount of heat energy: 2501 kJ/kg at 0C

At temperature t the heat content of water vapour is: hw = 2501 + 1.84t

Notice that water vapour, once generated, also requires more heat than dry air to raise its temperature further: 1.84 kJ/kg.C against about 1 kJ/kg.C for dry air.

The enthalpy of moist air, in kJ/kg, is therefore:
h = (1.007*t - 0.026) + g*(2501 + 1.84*t)
g is the water content in kg/kg of dry air

When I used the calculator found at http://www.natmus.dk/cons/tp/atmcalc/atmocalc.htm
I saw I remembered at least something half right.
to wit, mass of air can be way different in winter and high summer,
Two factors play their role.
air temp, and humidity.
cold humid air is lighter than cold dry air

I've oft told people riding a pushbike why its harder to ride in 30 klicks headwind during winter than during summer.
(I first read about this in a book by Isaac Asimov)
http://www.natmus.dk/cons/tp/atmcalc/atmoclc1.htm
extremes I calculated ranged from around 55 to 140 gram/cubic Meter

btw, don't let this fool you
but for completeness, you have to consider a fan has a limited capacity.
Your car top speed will be higher if air density is around 70, than it would be if it's around 110 g/cM. Its fuel consumption will be a lot higher while plowing through denser air at same speed.

a fan has to work to move air.
5 Watt will only move so many grammes/s
10 Watt will move more
the air contact surface and material its made of (the heatsink) will play a role in heat transfer.

And the thermal interface between the heatsink and die is truly important.
As a matter of fact, I am gonna get me some of that artic silver.
The stuff I got is adequate, but I'd like to see lower temp at full load.
(I already mentioned this, what use is a heatsink if one finds an insulator on the die...)

I just came across this last link I'll provide, since it looks like it belongs here. http://www.benchtest.com/clinks.html

Greengoose1,
in a way I have to thank you for "coercing" me to partake into these here discissions.
I am learning a ton.
https://discussions.virtualdr.com/

[This message has been edited by jtdoom (edited 06-11-2001).]

[This message has been edited by jtdoom (edited 07-04-2001).]

*Oh, Lordy...somebody's just GOTTA take jtdoom's Scientific Calculator OFF his system...* https://discussions.virtualdr.com/