Duct silliness

honegod

[H]F Junkie
Joined
Aug 31, 2000
Messages
8,192
my cpu required replacement so I went with a 10700K, I also got a NH-U14S for it.
all good.
but.
I really HATE clamping an axial fan directly onto a fin stack, as required for size constraints in a standard case.
having the top and bottom of the fan hanging out, just blowing air randomly is wastful of the fan potential,
although needed to keep the fan from stalling .
so now when I look at my computer I am not happy.
even though it works fine.
to restore my happy I am looking to duct the fin stack to a NF-A12x25 externally mounted on the back of the case.
where my previous cooler was similarly ducted.
I figure I should get at least equal total airflow through the fins even using a smaller fan by using it more efficiently.
I also figure to make the cooler more efficient by evening the airflow across the entire face of the stack, instead of the mutilated donut shape of the stock smashed together config.
 

honegod

[H]F Junkie
Joined
Aug 31, 2000
Messages
8,192
yes, my plans include some DiGiorno frozen Pizza boxes, my raw material of choice.
emptying them will take some effort but are worth the effort.
 

michalrz

2[H]4U
Joined
Jun 4, 2012
Messages
3,823
Noctua has those spacer things, you get foamy spacers to form your dream duct.
The NA-FD1.
Pendragon isn't wrong about mentioning cardboard, though...
 

honegod

[H]F Junkie
Joined
Aug 31, 2000
Messages
8,192
yes, I like those foam duct thingies, but they do nothing about the Very Important spacing of the fan away from the fin array.
a point of ducting is to get even airflow through the entire fin surface, not focussed on the swept area of the fan blades.
a thing I DISLIKE about the U14 is how the heatpipes are clustered to take advantage of the concentrated airflow at the sides of the fin array.
I would much prefer them to be evenly distributed across the face, like twin tower units do it.
but with the direct contact fan requirement that looks to be superior use of what is available, like the overhang stall prevention business.
 

honegod

[H]F Junkie
Joined
Aug 31, 2000
Messages
8,192
the U14S turns out to be not what I want.
it is just too bloody large.
it's too wide,the heatpipes interfere with the M.2 cooling, and the fins completely overhang the entire bottom half of the M.2
it's too tall, the fin stack fills up ALL the space above the motherboard to the top of the case.
the thickness is fine, and it cools just right. so as an emergency choice it was not bad.

a primary goal of this build is maximum storage, I am currently running
5 x 14tb, 3.5" harddrives, and I have 4 more waiting for a way to plug them in.

since the case I am using is a Lian-Li PC-Q33 itx

hgpcQ33.jpg

my stock drive capacity is 3.

two beside the power supply, the final mounted inside the case face.

hgQ335.jpg


since I want more than that, I removed the top/front and have the drives stacked beside the case, from the perspective of the photos (courtesy of newegg, where I bought it) on this side of the case, with all the wiring at the front so it is a straight shot to the PSU and motherboard SATA plugs.

I am now thinking about exactly how many drives I can actually stuff inside the case.
a second drive on the face cover would bring the total up to 4.
a third drive will barely fit on the face. 5
I could hang 4 more drives from the roof. 9

IF the CPU cooler didn't use up all that volume.

a Noctua D9 cooler is 55mm shorter than the U14, letting a 2 drive stack fit, barely, and with NO room for cooling air between them.

hgQ336.jpg


fun !
 

honegod

[H]F Junkie
Joined
Aug 31, 2000
Messages
8,192
a problem with the stock drive mount next to the psu is it uses the center screw hole of the spinner for mounting.
the 14tb do not have this mount, data crowded it out.
2 aluminium plates, drilled for the front and rear drive mounts, one above and the other below, would clamp the Lian Li mount
forming a nice triangulated box clamped to the drives.
a stack of shim washers to replace the absent L L aluminium at the cable end could calibrate the amount of flex that tightening those screws would bend the plates to.
the L L mount is fairly beefy and two thicknesses are a fair bend for the plates

the cheap big step drill should be good for making a cooling hole array aligned with, and continuing from, the L L pattern.
the original setup was to unplug both drives and remove the entire unit to remove either drive, on the bench.
3 screws clamp it to the rear of the case, right below the monitor cable.

I really do like the design of this case.
 

rhkcommander959

Limp Gawd
Joined
Mar 26, 2020
Messages
370
If you're gonna go through with ductwork, you should also make a spacer between the fan and noctua heat sink so you get 100% fin coverage instead of having dead space behind the fan hub. Most people just gut old fans, take some clippers and cut the supports to pull the fan hub/impeller assembly out and you have a ready-made fan spacer.

I would do this with triple radiators, made a difference especially with the big-hubbed fans of those times. With open fin heatsinks it won't help as much but hey, why not?
 

honegod

[H]F Junkie
Joined
Aug 31, 2000
Messages
8,192
so you get 100% fin coverage
that is the exact point of mounting the fan outside the case, to gain distance for the flow to equalise across the fin stack.
I would LOVE to be able to do a fluid flow model of the HS, fan, duct system and 3D print out the perfect flow guide duct to maximise flow at the heatpipe clusters at either end of the fin stack.

on my first [H] system I wanted maximum static pressure so I pulled the motor and blades out of a 120 and glued up a 120mm stator so I could stack two 120 in series,
one on either side of it,
pill bottles had just the right curve to carve vanes out of.
it worked, I got good temperature readings at a stable 200mhz overclock on my 950 thunderbird.
 
Top