Here are the new results:
By chance the performance of the
EK P280M rad is exactly the same as of the Corsair XR7 360, the 280 is IMO more practical thanks to its compact size:
Thick EK X420M:
Both rads in serie. This time the change of temperature of the room was so significant, that I had to include it in the calculation (marked blue). The measured performance WITH THIS CORRECTION was even slightly better than performance of individual rads summed, which suggests that not correcting the measurement for increase of ambient temperature slightly undervalues the real cooling performance of the rads.
The water flow in 280 rad was approx. 6 l/m, 420 6,5 l/m, both rads in serie 5,3 l/s. The real difference of performance of individual rads summed should not be that much higher than measured performance of rads in serie, because the drop in water flow is not that high.
Summing up my findings so far:
I believe these values are not that far from the real performance. It would
be really interesting to learn the performance of the rads with say 50% fan speed, but I am not planning to make this measurement. I think it would be safe to presume that the cooling power of the rads at this reduced fan speed or even overcoming some dust filters would be 30-45% of the above values.
I have at this moment two Corsair 280 slim rads in the PC. Upgrading them to these EK rads would improve the performance by about
30%, possibly more at lower fan speeds. These rads would be less water flow restrictive than the current ones (air probably too). These rads cost
80% more money than the current rads.
A NOTE ABOUT THE CALCULATION SHEETS: The second graph is not the end result, it is based on columns 8 and 9. There is one more graph based on columns 10 and 13 invisible in the screenshots, which is then used to determine the thermal resitance.
The final table with the results just uses the determined thermal resistance numbers, that is why the cooling power numbers are slightly different from those in column 13 of calculation sheets.
Again, whis was not a lab grade measurement, just something I threw together quickly, however with datalogging thermometer with at least two probes (ambient air going into rads and water temperatures), this simple method has a potencial to produce reliable numbers, and it is quite quick measurement, you just monitor the pretty quick process of the water cooldown, you do not need to wait extensive periods of time for the system to equalize or heat up in another possible measurement set-ups.