peltier temp when at idle

[randy]

I AM NEW TO PELTIER COOLING. I FINALLY THREW TOGETHER A DIRECT WATER COOLED PELTIET RIG. KINDA WEAK, 96 W PELT COOLED BY A 4 GALLON BUCKET AS A RADIATER/RES, POWERED BY A 230 W AT POWER SUPPLY. COOLING A PENTIUM III 1000 EB @1.25. NOW THE PROBLEM, MY TEMPS IDLING, AND SCREWING AROUND HOVER IN THE 40'S AND 50'S. PLENTY COOL FOR ME, BUT WHEN THE COMPUTER IS AT IDLE, I.E. SCREEN SAVER ON, IT CLIMBS TO THE 70'S. CAN'T FIGURE IT OUT. I THOUGHT IT SHOULD GET FROSTY AT AN IDLE. PLEAS HELP, RANDY.

[bigben2k]

First off, welcome to ProCooling.

Your problem is obvious: you can't use a res to cool down a system.

You have to remember that the heat that goes into the system, from the CPU has to exit somewhere. In your case, it exits where the surface of your res contacts the ambient air.

That being said, the warmer the water is, the more heat will be released into the air. If you think about it, there's no heat transfer when both the water and the ambient air are at the same temp.

In your particular case, you've got good temps at idle, but because the heat transfered is much higher when the CPU is really given a run, your water temps will rise, up to the point where the amount of heat that's transfered to the ambient air is the same as what the CPU is putting in the loop.

The solution here is to replace your res with a radiator. We mostly use car heatercores, because they're cheap and efficient.

With that, you'll bring your "load" temps back down to what you currently have for idle temps, and probably even lower!

[randy]

my temps are not raising under load. that is why i am so confused. when i wake my computer from idling the temp returns to the 40's and 50's even under load. i am pleased with temp's in the 40's and 50's, i am not looking to achieve sub-zero just real cool. what temp difference do you thimk i could get with a heater core? just need a cure for the temp rise at idle. thanks for the imput, and the welcome to the forums.

[bigben2k]

Understood.

There is something with your screensaver going on that's causing the CPU to be running, otherwise your temps would stay the same. Since there are more screensavers out there then there are sand grains on any beach, there's no way to tell.

The important point is that your CPU isn't running at idle, when your SS is on.

Pretty much any heatercore will do you a world of good. I don't know what kind of heat a P3 gives out, but I'm sure that with a heatercore, you'll be able to achieve temps near ambient, and probably below, regardless of the load on the CPU.

Did you ever check the temperature of your water? That alone should give you a good clue.

Here's an article on radiators, from Bill Adams. You don't need all the theory, but I think you'll get the point.

[utabintarbo]

Originally posted by bigben2k


There is something with your screensaver going on that's causing the CPU to be running, otherwise your temps would stay the same. Since there are more screensavers out there then there are sand grains on any beach, there's no way to tell.

If you are using one of the openGL screen savers, that could easily peg your CPU. We had a server once that was essentially unusable until we went to one of the more pedestrian screen savers. Those pipes look cool, but...


Bob