Hash Fellow robcat2075 Posted May 25, 2013 Hash Fellow Share Posted May 25, 2013 Explain this to me... A typical (air) fan cooler clamps a piece of conductive metal to the top of the CPU. The metal transfers the CPU heat to radiator fins that transfer the heat to air a fan blows across them... A typical liquid cooler also clamps a piece of conductive metal to the top of the CPU. The metal transfers the CPU heat to a flowing liquid that carries the heat to radiator fins that transfer the heat to air a fan blows across them... So... why does inserting that extra step of transferring the heat to a liquid before it gets to the radiator fins get any more efficient cooling? The ability of the radiator fins and the fan to discharge the heat at the end of the chain is the limiting factor in both cases, right? Any heat the fins can't dissipate stays in the system. Quote Link to comment Share on other sites More sharing options...
Tore Posted May 25, 2013 Share Posted May 25, 2013 Water cooling is less noisy! Quote Link to comment Share on other sites More sharing options...
*A:M User* Roger Posted May 25, 2013 *A:M User* Share Posted May 25, 2013 Water cooling *is* less noisy but the reason it is more efficient is water has a higher specific heat capacity. It can absorb more heat than can be removed by air cooling. That is the primary reason. If you are near a large body of water in winter it will be marginally warmer (or marginally cooler in the summer) due to this heat abosrbing capacity. Phase-change cooling (the kind your fridge does) is even better, though. And of course if you want real street-cred you need to use liquid nitrogen (but this is not practical long-term). Quote Link to comment Share on other sites More sharing options...
*A:M User* Roger Posted May 25, 2013 *A:M User* Share Posted May 25, 2013 And now that I think about it, liquid nitrogen cooling is actually phase-change cooling, since you are converting the liquid to a gas, just not going through the bother of using condenser coils. Quote Link to comment Share on other sites More sharing options...
Tore Posted May 25, 2013 Share Posted May 25, 2013 Plus the fact that the fan in a water/liquid cooled system isn't bound to sit on top of the heat source, but can be placed in whatever place that's most efficient. Quote Link to comment Share on other sites More sharing options...
Hash Fellow robcat2075 Posted May 25, 2013 Author Hash Fellow Share Posted May 25, 2013 Why is a fan for a water cooler quieter? They are the same shape, they spin at the same speed, they churn the same air. Water cooling *is* less noisy but the reason it is more efficient is water has a higher specific heat capacity. It can absorb more heat than can be removed by air cooling. That is the primary reason. But the water is not what discharges the heat. It is not like a river that carries heat from a nuclear power plant, where the heated water goes away and doesn't come back. The water in a CPU cooler is a closed loop. It is merely transporting heat to some cooling fins that are now a foot away from the CPU rather than two inches. The water can only lose as much heat as the metal cooling fins can take from it. The water itself discharges no heat from the system. The heat capacity by volume of water is only about 20% greater than copper. The thermal conductivity of copper is far greater than water, about 800x greater. Edit: I've been reading some more about this on TomsHardware... main conclusions from the article... -The potential advantage of watercooling is not that water cools any faster, it is that the water can carry the heat to a larger, more massive set of cooling fins that can be reliably bolted directly to a CPU. This larger set of fins may require less fan activity (noise) to cool it off. -In actual practice, however, few water coolers (of the ones they tested) are designed well enough to do a better job of dissipating heat and do it more quietly than a comparably priced regular cooler. Most do a poorer job of cooling or have to be noisier to cool more. Quote Link to comment Share on other sites More sharing options...
*A:M User* Roger Posted May 25, 2013 *A:M User* Share Posted May 25, 2013 Maybe the fan required can turn at lower rpm because it is larger and pushing air across a larger surface (the radiator)?? The fan I have on my radiator is a 120mm fan whereas the largest fan I've seen attached directly to a heatsink is 80 or 90mm. Maybe that has something to do with it? All I know is, is that I get a larger temperature drop using water cooling on my i7 than I did with a traditional heat sink. It is also quieter. It was not cheaper, though. Maybe there are some actual engineers out there that can shed some light on the subject? The mostly reliable Wikipedia had this to say: http://en.wikipedia.org/wiki/Water_cooling Quote Link to comment Share on other sites More sharing options...
steve392 Posted May 25, 2013 Share Posted May 25, 2013 I would have thought that these days there could be a water cooler but with freeon in rather than water a bit like a fridge works .But I know NOTHING <_> Quote Link to comment Share on other sites More sharing options...
Tore Posted May 25, 2013 Share Posted May 25, 2013 This is a paper from Intel on the subject - very technical though...:-) http://www.intel.com/content/dam/www/publi...-appl-paper.pdf Quote Link to comment Share on other sites More sharing options...
higginsdj Posted May 25, 2013 Share Posted May 25, 2013 Water is more efficient at transferring heat than metal is. In the first example, heat is being transferred from the cold plate to the exchanger via copper. In the second, water (or a liquid) is doing the transfer. If the former was more efficient then your car would have a liquid filled radiator! Quote Link to comment Share on other sites More sharing options...
thejobe Posted May 25, 2013 Share Posted May 25, 2013 i just put a ziplock bag of ice on my CPU. that cools it down nice and quick. Quote Link to comment Share on other sites More sharing options...
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