How it began...
Said Cathar one day... so from that, I produced:Extrapolating from what I'm seeing it tells me that it should be possible to build a purpose built PC cooling radiator that is:
~16x16cm in size for the core
14FPI
1" thick in the core
single pass
coupled with a single Papst 4412FGL (26dBA fan) sucking on the core via a shroud
and achieve a C/W of slightly less than 0.05, for basically the equivalent performance of the Thermochill 120.2 using a pair of the stronger and noisier 4312L's.
i.e. a silent, compact, and high performing radiator solution that for a water-cooling setup with say a single pump and a hot overclocked CPU running most anything should never really see water temps exceed more than about 4C above ambient.
So how's that for a pointer for a step in the right direction for PC radiator improvements?
As you can see, shrouded at 12.5 degrees from vertical results in it being rather on the large side... 12.5 degrees from Horizontal resulted in a shroud that wasn't worth bothering with as was ridiculously small... and it's single row, single pass.
^^ 14FPI... tis more see-thru than it appears in the photo... wasn't particularly well squared on the radiator...
^^ Beside a PC60 for scale...
^^ Hanging from an old MountainMods wrapper (old as they no longer use the U wrapper, they use 3x separate panels)
^^ And mounted in the MountainMods...
It was decided, obviously, that the shroud in place was far too large... so Cathar returned to the calculator and did some further number crunching...
So back to the drawing board we went, and we now have....Marci, been plugging through the calculations with a flow calculator and the shroud angle.
10-15 degrees shroud angle from the vertical is optimal for the 16x16 -> 12x12cm shroud, with a pressure drop of 1.9Pa given a 50CFM air-flow, for which 35-50CFM is about the sorts of air-flows we're targetting with the low-noise optimised design.
A 30 degree shroud angle (4cm shroud depth), yields just a 2.0 Pa pressure drop.
A 45 degree shroud angle (2cm shroud depth), yields a 2.1 Pa Pressure drop
Given that the sorts of low-noise fans we're talking about are generating 10Pa air pressures at the sorts of air-flow rates we're talking about, then the variation here is trivial at best. We'd only be talking about impacting air-flow rates by 1% by converting the shroud into a very convenient and compact 4cm depth device (fan mounted on outside), and by 2% from "optimal" if the shroud was an even more compact 2cm depth (fan on outside).
In fact, even moving to a super-compact 1cm depth yields just a 3% loss of air-flow from the "optimal" depth.
I would however suggest that 4cm (30 degree angle from vertical) would be a very nice shroud depth for both the blow and suck fan orientations, and still make for a very compact design.
Old Shroud vs New Shroud - quite a saving in the space department
Better shot showing fin spacing
Profile shot of single Rev2 shroud fitted to one side
Shroud without fan
So, that's the 40mm shroud done and dusted and all fitted to the mountainmods testrig. Now that we have it down to a useable size we can get on with proper testing. There was no point doing any indepth testing with the large Rev1 shroud as this obviously wasn't the final shroud, so any figures produced would be largely irrelevant unless used to theoretically predict how it would perform with the Rev2. Testing isn't for theorising in my book. On this project, the theory was done first. The goal of building the rad is to confirm those theories.
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Originally Posted by Marci
) but it is 12 FPI.
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