[Cooling tip] Air pressure shim for radiators when using "frameless" fans

[RejZoR]

I've talked about this few times in various threads and I had a guy ask me about it today through PM so I decided to make a full blown thread about it.

 

The idea behind it is that water cooling radiators require high static pressure for efficient passing of air through dense fin stacks of the radiator. When using classic rectangular shaped fans, they cover the entire radiator and close almost all the gaps between fan frame and radiator, ensuring basically all air they push at the radiator also goes through that radiator.

 

If you use fans like for example BeQuiet SilentWings 3, they have special anti-vibration corners which work great when it comes to noise, but those massive gaps also means you're losing tons of static air pressure there. Instead of fan blades pushing all the air through the radiator fin stack, the air is bleeding on the sides of the fan because the gaps are huge compared to fin stack and air will just bleed out where it has the least resistance. Which means you're not really pushing air through the radiator fins, it's just bleeding out on the sides and recirculating through the fan over and over. Now, some will still pass through the radiator, but with much lower pressure and thus lower efficiency.

 

I solved that by cutting thin but tough sheet of transparent plastic the exact size of fan openings and the size of entire radiator and placing them in between fans and the radiator, acting like some sort of shim that's preventing air from bleeding out of the fans on the side. All the air that's pushed in now has no choice but to pass through radiator fin stack.

 

This is especially important when you're using high static pressure fans. Without such shim, you're basically wasting all the fan potential or their main benefits anyways. It's odd to see some AiO coolers even come with such "frameless" fans out of the factory and don't use such shims. Which is really weird.

 

Anyway, if you think about it, it makes sense and only time I've ever seen anyone talk about it was actually on EK's website in description of their Vardar fans that have classic rectangular shape for this very reason. And that's where I got the inspiration to address that issue by creating this inexpensive shim for my SilentWings 3 fans specifically. Hell, at worst, you could do this using some thin cardboard if you can't get such plastic sheet. A thin marker and sharp utility knife so you trace those circles somewhat accurately. It's very inexpensive mod and if done well it's nearly invisible on the radiator.

[Bitter]

Has it made a measurable difference?

[RejZoR]

18 minutes ago, Bitter said:

Has it made a measurable difference?

I haven't measured it because there are just too many variables to do it properly. But the logic and fluid dynamics support the idea. Air has to go somewhere and if it goes out on the sides instead through radiator fin stack, there will be loses. Maybe Steve from Gamers Nexus could do it in a more scientific way. He's good at that and probably has the methodology to do it accurately.

[Bitter]

3 minutes ago, RejZoR said:

I haven't measured it because there are just too many variables to do it properly. But the logic and fluid dynamics support the idea. Air has to go somewhere and if it goes out on the sides instead through radiator fin stack, there will be loses. Maybe Steve from Gamers Nexus could do it in a more scientific way. He's good at that and probably has the methodology to do it accurately.

No I mean I get why it works and I've used similar methods to make the air go where I want but I was just wondering if it's actually doing anything that's measurable ya know.

[RejZoR]

5 minutes ago, Bitter said:

No I mean I get why it works and I've used similar methods to make the air go where I want but I was just wondering if it's actually doing anything that's measurable ya know.

I'd have to tear it apart and try without it again and measure both times. That's a lot of work because of how I have my cables routed and I'm not exactly in the mood for doing that. The photos are from weeks ago when I made this. I can say it works great in terms of cooling. I just can't quantify it in numbers for you unfortunately.

[Bitter]

4 minutes ago, RejZoR said:

I'd have to tear it apart and try without it again and measure both times. That's a lot of work because of how I have my cables routed and I'm not exactly in the mood for doing that. The photos are from weeks ago when I made this. I can say it works great in terms of cooling. I just can't quantify it in numbers for you unfortunately.

How about some feels, feels quieter? Feels cooler? Feels...good man?

[RejZoR]

10 hours ago, Bitter said:

How about some feels, feels quieter? Feels cooler? Feels...good man?

Feels cool man