Room Cooling CPU cooling

[Stiffe]

Lets say i have a computer underload at 60 degrees C
the computer itself woudl be like a little heaters

now lets say i get a new hsf and it drops down to 40C

would the room be the same temperature for both?


Discuss please

 

[SparkyJJO]

The CPU is still using the same amount of power regardless of whether it is at 60*C or 40*C. Same amount of heat is being put out.

Now, the new CPU cooler is more effective at moving the heat from the CPU to the air (making the CPU run cooler). However, that heat goes to the room air so technically your room could end up a little warmer than before you put the new HSF on the CPU.

 

[phile]

The mean room temp would be the same, assuming the heat dissipated from the CPU remained equal in both scenarios. What would change is how said heat was distributed across all the items in the room.

That's my story, and I'm sticking to it!

-phil

 

[PianoMan]

Originally posted by: SparkyJJO
The CPU is still using the same amount of power regardless of whether it is at 60*C or 40*C. Same amount of heat is being put out.

Now, the new CPU cooler is more effective at moving the heat from the CPU to the air (making the CPU run cooler). However, that heat goes to the room air so technically your room could end up a little warmer than before you put the new HSF on the CPU.

First statement is so true. In an ideal world, you'd have perfect heat transfer from the CPU to the case air, and from the case air to the rest of your room. Disregarding efficiencies (i.e., I2R losses in the CPU [typically, resistance is linear with temp], convective mixing, conduction from CPU to HSF, yada, yada, etc.) both cases would yield the same mean temp in the room (where phile was coming from). In more detail, you've got a higher temp w/lower flow rate that should equal the lower temp w/higher flow rate, and all this is mixed perfectly with the surrounding air in the room.

However, in the real world, with the hotter CPU config, the air exiting your case will be hotter (again, disregarding the case), so depending on your room's convective characteristics, you would actually feel HOTTER in this instance next to the computer as your CPU builds a nice "cloud" for you to enjoy while you're playing at your desk.

Interesting question.

PM

 

[Stiffe]

U see to me if its bad air ventilation in the computer
the computer itself will be hotter so it'll be like a heater.

Where as in if it has proper cooling the hot air is dissapating into the room quiker and the room will be dissapating that air just as quick

do i make sense at all?

 

[cmdrdredd]

Maybe you can turn your room into a refrigerator heh

 

[PianoMan]

Originally posted by: cmdrdredd
Maybe you can turn your room into a refrigerator heh

LOL.

PM

 

[VinDSL]

Originally posted by: phile
The mean room temp would be the same...

Correct answer!

 

[phile]

First Law of Thermodynamics

Wow, something I learned in college finally pays dividends!

-phil

 

[threepointone]

yeah, average room temp is the same, but the temp of the part of the room you're in (i. e. outside of case) increases in temperature. it's a lot of volume, though, so the average temp of the room apart from the case should increase in temperature probably no more than a degree or so

 

[Vertigo0176]

Originally posted by: Stiffe
Lets say i have a computer underload at 60 degrees C
the computer itself woudl be like a little heaters

now lets say i get a new hsf and it drops down to 40C

would the room be the same temperature for both?


Discuss please

Yes because it's still generating the same amount of watts.

 

[hoorah]

Most of you missed the answer completely.

The heat produced by the CPU is entering the room at a given rate that does not change. This raises the temperature of the room until the temperature of the room is greater than the surroundings. When this happens, the room looses heat to the surroundings, unless of course the room is insulated.

If you increase the convection coefficient of the heat transfer between the CPU and the air around it, you lower the temperature of the CPU. You do not decrease the rate at which the room heats up.

Without a high convection coefficient (i.e, no fans), the temperature of the CPU increases until the heat transfer rate equals exactly the heat transfer rate with the fans (until the chip catches fire )

So the temperature of the room can't be changed at all based on the convection coefficient, because overall you're not changing the heat transfer rate. Now, you could change the rate of heat transfer to the immediate local surroundings by decreasing the convection and increasing the temperature of the PC case, but thats not changing the uniform temperature of the room.