[SOLVED] How much space does a radiator need?

OrangutanSteve

Commendable
Mar 28, 2019
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EDIT: Sorry this was supposed to be in 'Cooling' but I clicked the wrong thing.

I'm currently designing a liquid-cooled Ncase M1 and I'm wondering how much space a radiator needs on either side. basically, if my setup is Fans, radiator, GPU, how much space would I need in between the radiator and the GPU block for it to function correctly. The pic is from Arjun Mehta on youtube and shows what I'm describing.
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Solution
How much of a gap you need depends on how much airflow you need to get rid of whatever amount of heat you need to get rid of. A few millimeters is enough to push a fair amount of air if you don't mind the fan noise that will come with the need for increased static pressure, more clearance will allow more air through at lower RPM and make things much quieter.
How much of a gap you need depends on how much airflow you need to get rid of whatever amount of heat you need to get rid of. A few millimeters is enough to push a fair amount of air if you don't mind the fan noise that will come with the need for increased static pressure, more clearance will allow more air through at lower RPM and make things much quieter.
 
Solution
I would say that gap is not sufficient. Generally you want to match the gap, to the area of the fans. Using some algebra:

(# of fans)pi(fan radius, usually 60mm)^2 = L*H

That's the ideal. You could probably cut that in half if you needed and still be fine. More than that you you'll have to work your fans much harder to get good temps.
 
I got a custom watercooled NCase and I would advise against a setup with a single slim rad at the bottom. You can only install a 20 mm rad and 15 mm fans. The position at the side with 30 mm rad and regular fans is far better. I run both as 2x240, but its a tight fit and I honestly wonder if my temps were the same ix I would remove the bottom rad and put 25 mm exhaust fans instead.