A discussion about case fans

vbimport

#1

In Dee’s excellent review of an Antec case, there is the mention of ‘negative pressure’ because of the large number of exhaust fans.

I think blowing cooler air onto hot devices is a superior cooling method, rather than ‘exhaust’. Both are important but since retail PC cases aren’t air-tight, I’m not sure how valuable ‘negative pressure’ is.

Since many cases are now coming with two top-exhaust spaces, I’ve wondered if the traditional back-of-case exhaust fan shouldn’t be reversed and blow additional cooler air towards the CPU and over it, past the RAM slots, leaving Top Fans as the only exhaust.

I also think that a changing fan-speed would create greater turbulence (changing air-flow) inside a case, which should - theoretically - be beneficial rather than having a set number of ‘eddys’ pooling up, always in one area inside the case.

But no, I don’t look forward to little mini-rotating room fans whirring left then right, then back again…

The base question becomes - “Why not have most of the fans blowing INTO the case and only a few top-exhaust fans?”

(By the way, on Dee’s Antec review, something that Antec excels in is the air-space between stacks of HDDs. I just wish their rail system was TINY so this air-space would have far smaller drive-bay reflective anti-airflow ‘faces’ near the chin-fans.)


#2

I use a software SpeedFan . It doesn’t work with all motherboards or if the fans are direct molex connected but I don’t have my fans that way . I usually use 75% speed.
It doesn’t control the internal fan in the power supply because it is direct connected as above.
Has anyone tried one with the “vapo” bearing ?
I saw some with that at Newegg & wondered if it was a good bearing.

A couple of things I think should be done are replaceable case filters on the intake side.

An electric cooler that can be put on the intake also .
Something like the coolers that plug into a cigarette lighter in a car & look like an ice chest . Mine like this looks like a lirge flat chip under some aluminum cooling fins. That should be very adaptable to a computer case . (should have its own power supply ).


#3

Oh yes, easily accessed intake-cleaners! That’s another RANT I have against case designers, and I wish I could get case-reviewers to severely degrade recommendations on those failings.

The Antec 302 Case has many fine points, but the bottom intake screen is removable only on one side. If the user puts that side in a difficult-to-reach position, then it won’t be cleaned by most users. (Putting it to be withdrawn only from the back would be slightly better, but the ideal would have been to give the user a choice - lower left side, right or back.)

Reviewers tend to give All Points for Ease Of Building and very little regard to “continued lifespan”, I find. I wish the reviewers had to support customers who run print-shops - the land of paper-dust.


#4

This is some old technology that didn’t catch on . I don’t know why .I don’t beleive it is available .

http://www.xtremetek.com/reviews/index.php?id=67

This is similar but on a larger scale :
http://www.barrytechsales.com/downloads/ko_refrigerantchiller.pdf


#5

Cholla, Hubby was shaking his head, laughing at this - more in a shock-n-awe way, sort of “What will engineers think of next?” way. He said he grew up with ‘evaporative coolers’ and said that, as we drive thru the Panhandle and on, we might see some of those old evaporative coolers on top of some old farm-house or out some side-window. He remembered those as a boy, spraying the outside pads with the garden hose, then coming inside to feel the “lush new cool”, he said.

So, what do you think about all-exhaust or mixtures of fans in cases?


#6

Just to let you know I have a large evaporative cooler In one of my windows.
If you don’t already know modern ones have a water line with a float shut off valve connected to supply water to the tank. Then an electric pump pumps water to the pads . I also have 3 refrigerated air conditioners (window units) . These get used in humid weather but when it’s hot & dry the evaporative cooler works great .

I actually think a mixture of fans is a good idea . I don’t have a cooling tower on my CPU but it is also a good idea. There are lots of things that could be done to keep computers cooler & cleaner. I wish the cooling units had caught on another thing I had thought would be a good is an exhaust pipe so to speak that either took the case exhaust to another room in winter & outside in summer.


#7

I think most modern PC cases use “negative pressure”.
To obtain negative pressure you are trying to suck more air out of the system than the amount of air that can get in.

Example:
You have 5 identical fans in a system, all running at the same speed.
3 of these fans are sucking air out of the system, and 2 of these fans are blowing air into the system. Negative pressure is achieved because you are sucking more air out than you’re putting in.

Negative pressure improves convection. So providing you position the exhaust fans at the top of the case, then all the hot air inside the case should be pulled outside of the case.

Spot cooling components by blowing air at them, can improve the temps of individual components, but if you do this you are reducing the amount of negative pressure. So while that spot cooled component has a benefit, the other components may not be cooled as well as they were before you added the spot cooling.

Remember when people used to remove the side of the case to keep the PC running cooler in hot weather?
Try that on one of these modern cases, and you find system temps rise, simply because you have removed the negative pressure.

The down side of negative pressure is. You must filter the air being pulled into the system, otherwise the system becomes covered in dust.


#8

I just finished changing the guts from 2 workstations and a server to new cases.

I noticed on the workstations that had A370 cpus that it worked best when I had the front floor fan blowing in,the back fan blowing out and the side fan blowing in.

On the server that had a P3 it worked out best have all 3 fans blowing out.

The A370’s are flat mounted to the MOBO and the P3 sticks up in the air off of the MOBO which I am assuming made the difference on how to set up the case fans.


#9

I’m still not sure about Negative vs Positive Pressure. Air Movement seems to be the most important factor, and “limited exhaust” and “high input” would create a lot of movement - turbulents - too. “Better”, though?

This may be so unique to each case, as Bean points out, AND for the components. Since we typically use a boot-drive plus RAID-able HDDs at the front (where chin fans are blowing in), it’s a setup that formal case-reviews hardly consider. “How much air-space is allowed between drives in the bays? How much flat-faced drive-bay structure knocks out direct-air?” Antec provides good spacing. Most other consumer cases don’t - why bother having multiple drive-bays with only a credit-card’s width of space between stacked drives? Why create a drive-bay tower that prevents cooling instead of encourages it?)

Dee’s recent review does have a couple of HDDs plus a couple of SSDs (I think that’s correct), which was closer to our customer setups.

Then in her above comments, she mentions “filters” and, YES, if case-reviews wanted to seriously degrade ANY case based on lack of intake filters OR the lack of Easily Accessible intake filters, I’d greatly appreciate that attitude!


#10

I’m certainly no expert on PC case air flow dynamics.
I guess some experimentation would be required to see what yields the best results, negative or positive pressure.

I have read that positive pressure requires a sealed case, although I’m struggling to understand why positive pressure requires a sealed case, and negative preessure doesn’t.

I’ve also read that negative pressure requires the GPU fan to exhaust the air out of the case, by means of its integrated cooler, I can understand the reasoning behind that.


#11

I’ve seen smoke-tests run inside glass-tower PC cases (following a trace of smoke from the intake-chin fans out the exhaust) and I hope to see more of that. It’s maybe the only reason for “window” cases, in my opinion.

I always get disturbed reading about “sexy” computer parts or hearing any positive comments towards “the window” as if people REALLY DO spend time ooh’ing and ahh’ing about Christmas-tree computer innards instead of doing real work with them!

I can hardly believe I ever read “sexy” about computer parts, or comments about ‘matching colors’. Computers wear Prada. Riiiight - [I]sounds like little boys who haven’t really learned about Girls yet[/I].

Where [I][B]IS[/B][/I] that hubby of mine? I know - out with the dogs and llamas, collecting eggs for breakfast…


#12

[QUOTE=ChristineBCW;2644499]I can hardly believe I ever read “sexy” about computer parts, or comments about ‘matching colors’. Computers wear Prada. Riiiight - [I]sounds like little boys who haven’t really learned about Girls yet[/I].[/QUOTE]

That sounds like me who hasn’t seen any woman (except those on the street, but that’s not any better than watching movies) and loves computer parts far more than girls.

Sexy cases and fans have been very popular here. Sometimes colors on a CPU fan’s useful. Zalman uses different colors to indicate different modes: silent, automatic, highest RPM… But most sexiness seems to do nothing but offer distraction and increase cost. Well, usually the guys spending much on those cases also have to spend US$1~2K a month on girls they are dating so hardware makers are conducting fair business.


#13

Oh, I know! I’d like to drag you down into our computer dungeon and make you compile programs for a few years instead! “That’ll teach 'em to drool over computer parts!!” :iagree::iagree:

With a daughter, though, you’ve liked some woman at least ONE moment in your history, though! Mate Selection is everything!

I’m still on a rampage to find the God Of Case Designs and inflict my will on him. Fewer 5.25 bays, more 3.5s, cases an inch deeper, an inch winder - give us more space between drive-bays and motherboards. Shorter cases, deeper and wider. Also, force them to give us easy access for dust-cleaning!

Next stop - I’ll hunt down the jerks who designed pedestal SATAs on motherboards and make THEM change out Cable #4 (lower middle connector) every minute of their workday for a month… see if they can’t figure out a much better design.


#14

[QUOTE=ChristineBCW;2644680]

With a daughter, though, you’ve liked some woman at least ONE moment in your history, though! Mate Selection is everything!

[/QUOTE]

It’s not one moment, but nearly forever. My ex-wife still matters more than anything, anyone, the next is of course our daughter. For the time being, I just hope she’ll become exceptionally good at the use of English and computers.

Those 5.25-inch bays have survived partly because Compact Disc and Digital Video Disc. Some Japanese companies more than once tried to make smaller discs popular, but MD was expensive and 8cm CD was rarely used. USB NAND sticks are cheap to produce, but still a 16GB USB stick should cost more than what a BD-ROM or DVD-ROM would cost. Since big cases continue to offer lots of 5.25-inch bays meant for CD and DVD writers, we myce.com freaks are partly responsible for some of the unproductive and retrogressive part of PC case design.


#15

We have some Disk Duplicators with multiple 5.25 drives, but outside of those, I’ve never run across a productive PC that needs 2 of them. Maybe water-cooler radiators would have a Best Fit at the top-front of any case, but I’d still be tempted to put those into the Facia instead of inside a drive-bay.

I know there are folks who use multiple burners in a single PC case but I’m still wandering in the King Arthur days of “Slow Burning Creates A More Reliably Playing Disk”.

I never think “fast burning” is a useful measure - Compatible Playability is the only game in town.


#16

I came across this some time ago,

Guess it kept his roof space cool!


#17

[QUOTE=YogiBoar;2645925]I came across this some time ago,

Guess it kept his roof space cool![/QUOTE]Now, that’s a cooling solution. :clap::bigsmile:


#18

[QUOTE=Dee;2645931]Now, that’s a cooling solution. :clap::bigsmile:[/QUOTE]

It needs a triple loop water unit so the place looks good also.:bigsmile::bigsmile::bigsmile:


#19

I think we’ve got a few boxes of those coolers, come to think of it. Solid copper. Worth a fortune to cable thieves, but our pawnshop droolers barely lift an eyelid. “Socket what? 478? Who cares? Now, ya gotta a Mallard solenoid for a TR7, maybe come see me again.”

Sheesh. Not even a TR8. Idiot.

British Leyland, ya let me down again.


#20

Copper on a house roof? Wikipedia says all the gold ever refined by humans amount to just a volume of 20 m x 20 m x 20 m, forming a cube 20 m on a side. It may be slightly over 20 meters on a side. I use cooper-based coolers for some of the previous-generation sockets to cool 3.5-inch HDD’s and motherboard chipsets.