DavidNJ

All of the measurements published seem to be the amount of heat dissipated at a 10°C air/coolant temperature differential. They measure different coolant flow numbers, however they tend to be fixed unless the the radiator can dissipate more heat than the coolant is carrying.

However, most systems have a fixed heat dissipation need. The size of the radiator and the its effectiveness (including the fans) determines the temperature differential needed to dissipate that amount of heat.

Isn't what we need to know is what the air/coolant temperature differential is for a given heat load. If there is a 200w processor, at a given air flow/air pressure differential, what temperature differential to ambient would a BIX 360, PA120.3, or GTX480 need? In Ira's shroud tests, he was running around 2-3°C differential to ambient.

billbartuska

What does they refer to?

If the rad dissipates more heat than the water contains then the water gets cooler, less and the water heats up. Assuming a constant load, either continues until an equilibrium state is reached. The air/water temp differential changes the same way.

NO, in all systems the heat load is dynamic. As CPU/GPU loads increase, more cooling is needed.

Well, yes and no...
Heat removed from components is carried by the water and then transfered to the air. So measuring the heat carried by either will tell how much heat is removed from the components. The problem is that measuring water flow is much, much easier/cheeper than measuring air flow. Since the same parameter (heat removed) can be determined for either, the testers use the latter

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DavidNJ

They in the first instance was the coolant flow rate.

The maximum heat dissipation need, say under OCCT or Prime95 is fixed. You aren't going the vary it as a cooling system adjustment parameter.

The point on the third is measuring heat dissipated as the variable is inadequate. And using a 10°C air/coolant differential is inadequate. We need to to see how cooling works at different air/coolant differentials, including differentials less than 10°C.

A radiator that works fine at 15°C differential may be much less effective at a 5°C differential. This would affect overall design...how thick are the cores...two pass vs. one pass., how dense the fins, how numerous the tubes, the air pressure and velocity between the tubes, etc.

ira-k

The closer you can keep your rad out to ambient delta the better off temp wise you are....The 10C standard is way to high I think...I hate ever getting over a 5C delta, with a 500W load I'm holding it at right around 4C.....Fans cfm, fan config and rad type and flow will all affect your rad out to ambient delta....

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ChielScape

at what voltage do you run that tec to get only 500W of load?

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AMD2600

You can measure the temperature difference between the water in vs. water out. Inline temperature gauges due exist.

OC_RoB

I have done 2 systems this way at the inlet and outlet of a MCR320QP and a PA120.3 The most I have ever seen it change is 1 degree C.

each with Yateloons and Panaflos.......

I honestly would expect more..... but Ambient has a great deal to do with it I guess? Im not sure why there is never much variant in the IN and OUT. For me anyway.

DavidNJ

The heat capacitance of the water does. 1 gallon/minute takes 265 watts to increase on degree. If you are running at 300 whats and 1.5 gallons/minute...you will never see more than a degree rise in water temps.

The question is, how did your water temps compare to ambient temperature?

Martinm210

Thermochill has both heat dissipated and c/w curvers that are based on that 10C result. I'm not sure if it's a linear relationship or some sort of curve, but I'm about to find out with some of my own testing.

http://www.thermochill.com/PATesting/

If you want a c/w value for any "Heat Dissipated" curves, just take the 10C/X watts dissipated" and that's your c/w.

If the relationship is linear your water/ambient delta would then be this c/w value X the #Watts dissipating.

Example

PA120.3 Nexxus fans at 7V


Heat dissipated at .5GPM is 200watts.
10C/200watts = .05C/W

That matches the c/w posted in their c/w chart here:


Swiftech and Thermochill are the only ones to have any sort of c/w curves posted on their radiators. That's a big part of why I took an interest, I got tired of all the guesswork happening and hoping I can provide something useful.

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