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Info New High Airflow Case Design

Hardware Hound

Junior Member
Dec 22, 2020
3
1
6
blur-photo.com_1608137622.jpg

Got a new case design I'm sharing with everyone. I've shared this at several forums now and yes, I hope this is a design that can make it to market someday soon. However, I've gotten some interesting push back on the design based on suggestions from untested illustrations. I want to start by explaining in detail my theory on why this design is necessary for airflow. I'll also show the graphs that kind of prove my theories, though I hope to do more testing in the future. I feel like AnandTech is a more technical site, so I feel the detailed explanation will be a bit more appreciated here.

blur-photo.com_1608137622.jpg

Long story short, I've been working on improving airflow for years on a computer case. This is a personal project I took on for my own Crossfire/SLI heat problems. After testing several different ideas, this is the first one that worked, and even worked overall, above my expectations. Basically, I studied wind tunnels to see how I could get this to work. I thought I would discover some super technical means to improve airflow using a series of fans. Instead, I discovered one big fan in the front of the tunnel and one big fan at the back of the tunnel. The two fans are placed, exactly parallel to each other to maximize airflow in the testing spot. I've tried this before using fans at the bottom and top of a case and moving the PSU out of the way. Unfortunately, the chimney effect heated up all the upper components, making the tradeoff not worth it.

Case Invention Compressed (1).jpg

Of course the problem with parallel fans in the front and back is that we need room for our cables to plug in. EVGA tried using a secondary back panel with the DG-87 case, but Hexus tested it and the results were underwhelming. There's two problems that case has. Number one is that the normal back panel will act as a restriction to airflow. The other problem is that distance also hurts airflow, and the extra back panel puts more distance between the fans where air needs to flow. While it took me a while to come to this conclusion, the angled back panel was the perfect answer. It allows air to travel as straight as possible, with the shortest distance, and prevent a chimney effect in the components. Also, the smallest face of the graphics card is angled directly at the fans. Basically, the card is a big flat board which can restrict airflow. Having its smallest edge facing the fans allows the air to flow around it the easiest. That's why my temps showed a pretty dramatic improvement system wide I believe. The cards were less dramatic, since the limitation is probably the heatsink size. Also, the R9 290X pushed the limits so much that airflow is unlikely to do much. I hope to test with a different high end card in the future.

Crossfire Gaming Test.jpg

Also, noise levels were pretty dramatically improved. I even stopped my 140mm fans and was still humming at 42dB in my Thermaltake Core V71 test case. Here's why I think it that happened, even though both cases had the same NZXT 200mm fans. You hear a lot about positive or negative pressure in case airflow. While evidence is strong that positive pressure is better, pressure in and of itself is a bad thing. It indicates that the case is restricting airflow. My theory is that those pressure differences can cause a resonance in the fan blades, reflected in increased noise. The reason we have pressure problems is really, changes in direction and elevation of intake and exhaust fans.

Noise Levels.jpg

Remember, the wind tunnel keeps the fans exactly parallel to each other. Air doesn't naturally change directions. While the nice little marketing arrows show cool air entering the bottom front of the case and gently sloping upwards to exit the top back, that isn't what will happen. The reality is the air will blow directly into the case, collide with the components and panels in the back, and start bouncing off in all kinds of directions. This is basically turbulence inside the case. While some molecules will spin around, get pulled up and find the exhaust fans out of the case, others will spin around for periods of time collecting more heat. This is inefficient and while it may not matter for mid range or budget components, this can really hurt performance or stability in higher end components that generate a lot more heat. While my new design still has an angle and isn't perfectly parallel, the change is minor enough that air flows at peak efficiency through the components without having a chimney effect. Also, the angle puts the intake and exhaust fans closer so that the air doesn't have a chance to slow down as much.

I work a full time job and just had a new baby, so testing these theories more will take me time. However, I have a plan to show this a bit better. I want to run my gaming tests for 3-4 hours and try to find the case equilibrium. Based on experience, I expect it would take around 2 hours on my traditional case to reach that. I need to get numbers though. If my experience is accurate, then my new design will have reached equilibrium in the first 30 minutes. In other words, gaming for several hours won't cause everything to slowly heat up more and more as heat builds up in the case. Here's some more pictures so you can see the design. I did file a patent pending just in case my design is patentable, but I really don't care if it is or not. I would just love to see this design in a production case, rather than my plastic cardboard / duct tape prototype.

Case Invention Compressed (3).jpgCase Invention Compressed (4).jpgCase Invention Compressed (5).jpgCase Invention Compressed (6).jpgCase Invention Compressed (8).jpgCPU Test.jpg
 
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Jimminy

Member
May 19, 2020
114
36
61
You might be able to lower the temps a tiny bit if you turn off the RGB bling. In critical wind tunnel designs, every little bit helps.
 

Hardware Hound

Junior Member
Dec 22, 2020
3
1
6
You might be able to lower the temps a tiny bit if you turn off the RGB bling. In critical wind tunnel designs, every little bit helps.
Actually, the sun is what causes the wind currents on the planet. It's clear that RGB is helping airflow, not hurting it! lol
 

mindless1

Diamond Member
Aug 11, 2001
5,855
591
126
It seems a bit like you are taking great effort and possibly added expense to end up with a drop in temperatures that is not needed, as long as the temp is low enough to have stability and promote acceptable lifespan.

You started with the premise that the base case is 4 x 200mm & 2 x 140mm fans while that isn't the average case, more of something manufacturers use as a marketing feature. It can depend on what you're doing with your GPUs but a pair of cards for gaming does not need 4 x 200mm fans. A single side panel fan on a case that has only two 120mm fans will work. The larger fans do allow less noise if set up properly but if at the same RPM to reach lower temps, you have more noise and then there is dust.

A "little" positive case pressurization is a good thing. The small amount of airflow lost is not as important to many owners as not having dust come in every nook and cranny, including depositing in the rear I/O ports. Some people, myself included, want positive pressure and accept even further reducing airflow with effective filters in the intake fans to keep more dust out. Few cases have filters that are effective enough, so making the entire front ineffective at filtering dust, is a step backwards to those people.

Over time this reduces the maintenance of cleaning the case out, made even more burdensome if you have a lot of fans, and between cleanings, having less dust deposit on the video card heatsinks (where your primary cooling airflow rate requirement comes from in most cases) results in a better temperature to airflow & noise ratio.

I'm not suggesting that the way you set that case up is a bad idea, just something that is pretty subjective, not desirable to everyone and not needed to have a stable, reasonably quiet system, provided you aren't putting the system right next to your monitor on the desk so the front fan turbulence is a fairly close, straight shot to your ears.

I do think there's a market for this case design, and that it's better than the one in your pics where there's 3 fans on the botton and 3 on the top, which was never optimal for an ATX case. Front in, rear out was always the best place for the primary fans, unless the motherboard uses a design altered to rearrange everything to better suit top and bottom fans which would be difficult because it would put the rear card ports on either the top or bottom of the case while most people want them in the rear. Of course there are exceptions, a bottom fan directly under a single video card instead of two cards, can also be effective, but you only need one fan on the bottom for that.

One other issue is the way the rear fans are slanted, it creates extra burden to access the rear of the case interior. I'm not the type to muck around much in a case once a system build is complete so it wouldn't bother me much but others are more often fiddling around inside, including having to clean dust out if it doesn't have positive pressure and a filtered intake.

Lastly about cost. I don't buy new cases anymore, don't need to when I can recycle used ones to reuse, so an additional cost to make that case, as well as the 4 x 200mm fans, is going even further away from my needs. Also if you don't have filter panels nor fan guards, that's a lot of open area with blades spinning around. The design seems to make a lot of concessions so it is a niche that would take targeted advertising to reach the right buyers.

blahblahblah, you should just ignore me, I was never your target case owner. ;)
 
Last edited:

BonzaiDuck

Lifer
Jun 30, 2004
14,817
1,005
126
It seems a bit like you are taking great effort and possibly added expense to end up with a drop in temperatures that is not needed, as long as the temp is low enough to have stability and promote acceptable lifespan.

You started with the premise that the base case is 4 x 200mm & 2 x 140mm fans while that isn't the average case, more of something manufacturers use as a marketing feature. It can depend on what you're doing with your GPUs but a pair of cards for gaming does not need 4 x 200mm fans. A single side panel fan on a case that has only two 120mm fans will work. The larger fans do allow less noise if set up properly but if at the same RPM to reach lower temps, you have more noise and then there is dust.

A "little" positive case pressurization is a good thing. The small amount of airflow lost is not as important to many owners as not having dust come in every nook and cranny, including depositing in the rear I/O ports. Some people, myself included, want positive pressure and accept even further reducing airflow with effective filters in the intake fans to keep more dust out. Few cases have filters that are effective enough, so making the entire front ineffective at filtering dust, is a step backwards to those people.

Over time this reduces the maintenance of cleaning the case out, made even more burdensome if you have a lot of fans, and between cleanings, having less dust deposit on the video card heatsinks (where your primary cooling airflow rate requirement comes from in most cases) results in a better temperature to airflow & noise ratio.

I'm not suggesting that the way you set that case up is a bad idea, just something that is pretty subjective, not desirable to everyone and not needed to have a stable, reasonably quiet system, provided you aren't putting the system right next to your monitor on the desk so the front fan turbulence is a fairly close, straight shot to your ears.

I do think there's a market for this case design, and that it's better than the one in your pics where there's 3 fans on the botton and 3 on the top, which was never optimal for an ATX case. Front in, rear out was always the best place for the primary fans, unless the motherboard uses a design altered to rearrange everything to better suit top and bottom fans which would be difficult because it would put the rear card ports on either the top or bottom of the case while most people want them in the rear. Of course there are exceptions, a bottom fan directly under a single video card instead of two cards, can also be effective, but you only need one fan on the bottom for that.

One other issue is the way the rear fans are slanted, it creates extra burden to access the rear of the case interior. I'm not the type to muck around much in a case once a system build is complete so it wouldn't bother me much but others are more often fiddling around inside, including having to clean dust out if it doesn't have positive pressure and a filtered intake.

Lastly about cost. I don't buy new cases anymore, don't need to when I can recycle used ones to reuse, so an additional cost to make that case, as well as the 4 x 200mm fans, is going even further away from my needs. Also if you don't have filter panels nor fan guards, that's a lot of open area with blades spinning around. The design seems to make a lot of concessions so it is a niche that would take targeted advertising to reach the right buyers.

blahblahblah, you should just ignore me, I was never your target case owner. ;)
There are at least a few of your key points with which I agree.

Right now, I'm starting to window-shop for a new case. But my flagship system -- down for repair -- uses an old Coolermaster Stacker 830 mid-tower. The Newegg page says "full tower", but the 830 is indeed the case I'm using, and it's a mid-tower.

As BonzaiDuck on these forums since around 2005, I -- maybe others -- called me the "Duct-Meister". I wish I had the the pics for my Skylake system, but, as I said, the system is down for repair, and it will only be a matter of luck if I find them on my server upstairs. I'll take a look later to see what I can post here.

The web-search turned up someone on EBay offering the Coolermaster 830 for $299. I found that offer a few days ago, and was inspired to go back and toy with the idea of paying the buckets of ducats to obtain a case which is probably a 15-year-old design. Then, I discovered the seller is located in Russia. It's not the shipping cost of $100 that concerns me -- note that I had used the Kaspersky anti-virus for more than ten years. I just decided to back away from the prospect.

Purpose of ducts is to restrict airflow by directing it through narrowed apertures to targeted hot-spots. When I started to tear down my Skylake, I felt nearly awestruck to see what I'd done with this case four years ago. I'm trying to remember how many times I'd pulled the case apart between October, 2016 and June, 2017. I almost fail to believe that I built that thing.

I was not too eager to take out the CM 12" barrel-fan so I could get at the SATA plugs, because I remembered the screws and "shock-absorbers" were tiny and come apart easily, but it was no problem at all. The barrel fan sucks air off the motherboard from under a Lexan duct-plate. There are two 140mm sidepanel fans (the CM 830 has a hinged fan-frame that allows for four such fans). Two more 140 Viper fans feed the case front. Everything is filtered. I built an interference-fit frame of foam-art-board and metal screen for the front 140's. I similar foam-board and screen fits on the opposite side of the motherboard panel over a matrix of holes in the aluminum for under-mobo air-flow, so the barrel fan sucks air from under the board as well as from the topside and the Lexan panel.

What amazes me is the dust -- there is a total lack of cruft inside the case, but there is still a barely-noticeable film of very, very fine dust on the inner components. The barrel fan acts as an exhaust, blowing air out the right side of the case, and a Gentle Typhoon AP-30 120mm as rear-exhaust complements a 140mm Viper fan on the front of the Grand Macho cooler -- ducted from its rear side to the AP-30.

I REALLY want to build another system just like this one, but I won't be able easily to find another CoolerMaster 830. Even so, some of the new Coolermaster cases still have a place for the barrel fan.

The side-panel fan-pair and the front fan-pair, together with the two heatsink fans and barrel-fan are controlled by the motherboard and PWM splitters. Nobody can tell me my system is noisy, AP-30 notwithstanding. I always choose intake fans so that the total rated CFM exceeds the exhaust CFM. The ducting does the rest of it.

I will look on my server to see if I saved some snaps there . . . .
 

SamMaster

Member
Jun 26, 2010
100
40
91
There are at least a few of your key points with which I agree.

Right now, I'm starting to window-shop for a new case. But my flagship system -- down for repair -- uses an old Coolermaster Stacker 830 mid-tower. The Newegg page says "full tower", but the 830 is indeed the case I'm using, and it's a mid-tower.

As BonzaiDuck on these forums since around 2005, I -- maybe others -- called me the "Duct-Meister". I wish I had the the pics for my Skylake system, but, as I said, the system is down for repair, and it will only be a matter of luck if I find them on my server upstairs. I'll take a look later to see what I can post here.

The web-search turned up someone on EBay offering the Coolermaster 830 for $299. I found that offer a few days ago, and was inspired to go back and toy with the idea of paying the buckets of ducats to obtain a case which is probably a 15-year-old design. Then, I discovered the seller is located in Russia. It's not the shipping cost of $100 that concerns me -- note that I had used the Kaspersky anti-virus for more than ten years. I just decided to back away from the prospect.

Purpose of ducts is to restrict airflow by directing it through narrowed apertures to targeted hot-spots. When I started to tear down my Skylake, I felt nearly awestruck to see what I'd done with this case four years ago. I'm trying to remember how many times I'd pulled the case apart between October, 2016 and June, 2017. I almost fail to believe that I built that thing.

I was not too eager to take out the CM 12" barrel-fan so I could get at the SATA plugs, because I remembered the screws and "shock-absorbers" were tiny and come apart easily, but it was no problem at all. The barrel fan sucks air off the motherboard from under a Lexan duct-plate. There are two 140mm sidepanel fans (the CM 830 has a hinged fan-frame that allows for four such fans). Two more 140 Viper fans feed the case front. Everything is filtered. I built an interference-fit frame of foam-art-board and metal screen for the front 140's. I similar foam-board and screen fits on the opposite side of the motherboard panel over a matrix of holes in the aluminum for under-mobo air-flow, so the barrel fan sucks air from under the board as well as from the topside and the Lexan panel.

What amazes me is the dust -- there is a total lack of cruft inside the case, but there is still a barely-noticeable film of very, very fine dust on the inner components. The barrel fan acts as an exhaust, blowing air out the right side of the case, and a Gentle Typhoon AP-30 120mm as rear-exhaust complements a 140mm Viper fan on the front of the Grand Macho cooler -- ducted from its rear side to the AP-30.

I REALLY want to build another system just like this one, but I won't be able easily to find another CoolerMaster 830. Even so, some of the new Coolermaster cases still have a place for the barrel fan.

The side-panel fan-pair and the front fan-pair, together with the two heatsink fans and barrel-fan are controlled by the motherboard and PWM splitters. Nobody can tell me my system is noisy, AP-30 notwithstanding. I always choose intake fans so that the total rated CFM exceeds the exhaust CFM. The ducting does the rest of it.

I will look on my server to see if I saved some snaps there . . . .
I'm using a Cooler master HAF XB Evo in my main rig. Another high air flow case. The 140mm front fans are controlled by the motherboard and only ramp up past 65C on the CPU. Even when gaming, the system stays quiet.
 

BonzaiDuck

Lifer
Jun 30, 2004
14,817
1,005
126
I'm using a Cooler master HAF XB Evo in my main rig. Another high air flow case. The 140mm front fans are controlled by the motherboard and only ramp up past 65C on the CPU. Even when gaming, the system stays quiet.
Well, I couldn't find my snapshots on my server. They're on the system that's down for repair. I really need to get to work on it. I'll finish testing the old Sabertooth board, and go from there. I couldn't help myself: the Skylake i7-6700K was great and certainly good enough, but I found an i7-7700K retail-box in unopened shrink-wrap, and plan to send it to Silicon Lottery for their $40 delid-relid service.

I really did a great job with that Coolermaster 830. Without the pictures, it's harder to explain.

Anyway, high-airflow experiments are interesting. The OP's project is interesting. Personally, I want some front bays for devices, USB ports, removable drives and so on.

And, as I said, the key is not simply to push gobs of air through the case -- in and out. You can use less CFM, smaller fans -- use some strategically placed ducts, pressurize the case and get the best air-cooling that is likely possible. Of course, building ducts is tedious. A motherboard duct-plate is best made out of Lexan, so you can see the board and components. You can fuse Lexan and black foam-art-board, which reduces the drudge of cutting extra Lexan parts. A heatpipe cooler like the Grand Macho has an accordion-duct accessory you can buy.
 

BonzaiDuck

Lifer
Jun 30, 2004
14,817
1,005
126
Anyway -- I don't want to rain on the OP's parade. The high-airflow DIY design looks nice. It's got a "lotta fan", but it apparently works. I'd just want more removable drive caddies, an optical disc, some front-panel USB ports and so on.
 

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