Case Ventilation Questions

Kmpkt

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Feb 1, 2016
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Hey Guys,

As I've mentioned previously, I've been working on a case design for a while. I am currently going back and forth between a couple of venting/airflow patterns and was hoping people here could help me out a bit with deciding what will likely provide the best cooling. The current layout of components is essentially like that in the Firewolfy MI-6 and Hutzy XS with HDPlex 300 AC-DC directly under the GPU and DC-DC board directly under the motherboard. The power delivery components can be moved to accommodate airflow. Airflow options I am considering are as follows:

1.) Vented side panels like the S4 mini. Solid aluminum top, bottom and front panels and some ventilation at the back around the I/O. No case fans as GPU/CPU have direct access to airflow from the outside via side panels. ~1cm of space between side panel and CPU/GPU coolers assuming a 40mm CPU cooler like the L9i. AC-DC and DC-DC power components would need to cool passively although there is a significant amount of heat sinking onto the case itself for both of these components

2.) Vented front panel with intake fans, vented back panel, all other panels solid. Forced air moving across all components from front to back. The GPU and CPU would each have about 1cm of clearance to the side panels.

3.) Solid front panel with vented top and bottom panel moving air in a pattern like the Lone Industries L1 and solid side panels. Power components would move to inside of front panel and fans would either go at top or bottom with a view to moving air upwards to exhaust out the top of the case.

I'm open to any other suggestions as well regarding potential layouts. The overall width right now is 127mm and I'd ideally like to keep that dimension. The other dimensions are open for modification. Cheers for any advice people can offer on the matter.
 
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Thehack

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I would say having the 1st layout makes the most sense. It is efficient, allows cool air access, requires no additional fans to take up more volume. The 2nd requires at least 10mm of clearance for your cooler, which adds to volume in addition to front fans.

At 127mm width total width, that is really wide for a DC/DC board case. What's your reason for that? My current build is 144mm wide that uses the Meanwell PSU, and that is with no riser.
 
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Kmpkt

Innovation through Miniaturization
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As far as 127mm for width, a dual slot GPU is typically about 40mm wide. Add another for 40mm heatsink, and another probably another 20mm for the motherboard tray, offsets, motherboard and CPU and you're already at 100mm. Add 10-15mm to each side for cooler clearance so you don't suffocate them against the side panels and you've got 127mm. Were I to perforate side panels to allow fresh air straight into the GPU/CPU I'm not certain it would do a ton to slim the case more than 10-15mm.

Secondly this not merely a DC-DC board case. I am planning to have both the new HDPlex 300W AC-DC internally as well as a custom variant of the 300W DC-DC sitting side by side on the bottom of the case. The new HDPlex AC-DC is 62mm wide and has cooling fins on the sides and as such should probably be allotted 70mm if you're going to have air circulated over its surface (which I am planning to). The HDPlex DC-DC 300W board which my custom solution should be roughly as wide as the new 300W-Hi-Fi-DC-ATX at 53mm. Again 127mm is pretty much spot on for these two components to sit side by side. I'm pretty much bound to this width for both of those reasons.

Looking back on my OP, I think I wrote the question poorly. I am currently using option #2 in my design and am quite far along with it, but am wondering if I would be better off either pulling the fans and perforating the side panels to reduce size and simply rely on the CPU/GPU fans to do their jobs adequately through the side panels. The obvious upside to taking the fans out is that I reduce case size by about 10% (210mm down to 185mm). The downside is that I lose active cooling to the AC-DC and DC-DC elements of the case which worries me somewhat. Furthermore, I can't help but think that with fresh air pushed across both the GPU and CPU, thermals would be significantly improved.

Thanks for the input anyhow and hopefully I've clarified things a bit. I'm trying to figure out how to get some screen shots from the 3D PDF my designer sent me last.
 

Thehack

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As far as 127mm for width, a dual slot GPU is typically about 40mm wide. Add another for 40mm heatsink, and another probably another 20mm for the motherboard tray, offsets, motherboard and CPU and you're already at 100mm. Add 10-15mm to each side for cooler clearance so you don't suffocate them against the side panels and you've got 127mm. Were I to perforate side panels to allow fresh air straight into the GPU/CPU I'm not certain it would do a ton to slim the case more than 10-15mm.

Secondly this not merely a DC-DC board case. I am planning to have both the new HDPlex 300W AC-DC internally as well as a custom variant of the 300W DC-DC sitting side by side on the bottom of the case. The new HDPlex AC-DC is 62mm wide and has cooling fins on the sides and as such should probably be allotted 70mm if you're going to have air circulated over its surface (which I am planning to). The HDPlex DC-DC 300W board which my custom solution should be roughly as wide as the new 300W-Hi-Fi-DC-ATX at 53mm. Again 127mm is pretty much spot on for these two components to sit side by side. I'm pretty much bound to this width for both of those reasons.

Looking back on my OP, I think I wrote the question poorly. I am currently using option #2 in my design and am quite far along with it, but am wondering if I would be better off either pulling the fans and perforating the side panels to reduce size and simply rely on the CPU/GPU fans to do their jobs adequately through the side panels. The obvious upside to taking the fans out is that I reduce case size by about 10% (210mm down to 185mm). The downside is that I lose active cooling to the AC-DC and DC-DC elements of the case which worries me somewhat. Furthermore, I can't help but think that with fresh air pushed across both the GPU and CPU, thermals would be significantly improved.

Thanks for the input anyhow and hopefully I've clarified things a bit. I'm trying to figure out how to get some screen shots from the 3D PDF my designer sent me last.

The suffocation occurs because of low perforation. You will encounter the same issue if you put the fans in the front. In order to overcome it, you need one of two things:

1) Large free-flowing vents.

2) 25mm Static pressure fans.

Cases like Dan's have small perforation. I'm sure Dan did tests comparing performance vs strength vs aesthetics and decided on his perforation ratio. Whether you put fans in the front or allow the coolers own fan you will have to deal with it regardless. If you add large cutouts you could've done it for the sides as well. If you have small perforations, then you need to have enough static pressure and that requires bigger fans which requires more space. So in the end, the only logical answer is to use the side panels as air vents since you're going to deal with it regardless. If Dan had gone for more perforation ratio, he could have easily had a case whose performance is even closer to an open bench.

If the perforations aren't open enough, and you give it space, it may make it worse as the GPU may recycle the air around it since now their is a buffer of air above it.

I would add a 40mm fan in the front, to keep air moving over the DC-DC and PSU components.
 

Lone

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#1, plus if you can add a single small fan to pull air across the AC-DC then that would be ideal. The 160W AC-DC I have gets surprisingly warm.
 
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Kmpkt

Innovation through Miniaturization
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Yeah I've used the same one (I assume you mean HDPlex) and it's quite warm. It's why I'm worried about not having forced air through at the very least that portion of the case. I'm thinking of taking out the top fan (120mm) now to provide more space for the GPU.
 

Aibohphobia

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Do you have a prototype that you could mock up the various panel variants with cardboard? That's what I did for Cerberus in the beginning, because we can speculate all day but in the end it's empirical data that counts.
 

Kmpkt

Innovation through Miniaturization
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KMPKT
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I don't have a prototype yet, but am planning to roll one out as soon as I can get a trial version of my DC-DC which I anticipate to be in Feb/March. I'd ideally like to hash out all of the potential issues by bouncing ideas off more experienced designers now so that hopefully there isn't much refinement to be done when I actually go to production.
 

Aibohphobia

aka James
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You could cobble together something I'm sure. Here's my thermal test rig for what became Cerberus:



I took an old SG02, gutted the frame, then taped cardboard panels to it, but it worked :p