neo86 said:
RhoXS, wouldn't having a slower pump allow more time in the radiator also thus allowing more time for heat exchange there?
Neo, you do
NOT want the water in the radiator very long. The longer the water is in the radiator, the cooler it gets. That's good, right? Wrong. It decrease delta T between the water and the cooling air. Decreases in delta T mean efficiency will decrease. If you want your radiator to dissipate the maximum amount of heat, let the water get real hot. That's good, right? Wrong. That will decrease the delta T between your CPU and the water, decreasing efficiency there. If you want to dissipate the most amount of heat at your CPU, get the water as cold as possible. You want to do this again? Cause it goes in circles. The "sweet spot" is a natural equilibrium that will occur based on CPU temp, ambient temp, and water and intake air flow rate. RhoXS is 100% correct, more flow is better, hands down, no argument. Physics does not lie. For both water and air.
He is also right on with the heat from the pump, cruel world, isn't it? More flow, more better, more flow, more heat. Find the balance. The beautiful thing is that it takes a lot of energy to heat up water. As the water flows past the CPU, it does not pick up that much energy, so temp does not increase that much per pass. This means that small flow rates are fine on the CPU side, and increasing rates will decrease returns quickly. Radiators are different though. There is a lot of surface and tube to flow through in a rad, so temp will drop significantly in a rad per pass. So high flow is more important for rads.
One thing also that I should mention, intake air is the same concept. More flow, the better. And since the air is exhausted and not recycled(I'm not gonna get into your room as a system, in which it is recycled, so we can assume constant ambient temp) "pump heat" for air is negligible. More air es bueno. Hands down, no argument. If you can increase air flow or rad surface area to the point that it will drop rad temps to near ambient, that is very good, but very hard. As rad temps decrease, delta T decreases, decreasing efficiency. Thermodynamics sucks, huh?
The lesson from this? Increasing flow rate is good, for both air and water. Air is better since it has less consequence for increases in flow, no "pump heat". But both increase rad efficiency. Hope this helps, RhoXS did a pretty good job, but I was bored and felt like kicking in support for him.