i've decided i'm going to suspend the hard drive in a vacuum. the drive will be in a aluminum tray suspended by heavy duty rubber bands in a plastic vacuum chamber.

i'm going to rely on convection alone for heat transfer, which would seem to work okay due to the passive aluminum tray/heatsink.

only question is would the drive work in a vacuum. i would think it does, but that 'breathing hole' of the hard drive does concern me. does it need air to suck in and out for internal cooling?

this would be for my backup drives that will be replaced by barracuda v.

It think another question is will convection work in a vacuum? And that is definetely a no! Heat wont travel through a vacuum except by radiation, so i would think the HD would overheat very quickly unfortunately...

Sorry to put a downer on yer idea, but i think it would end in a burned up HD

sorry. i meant to say radiation, or is it?

if i remember correct from yyyeeearrrrs back, there are three different ways for heat to 'move'.

convection (air)
something else (by solid medium)
radiation (just as sun heat reaches its planets)

correct me if i'm wrong.. i could use some physics lesson

Yes, then you meant radiation. But even still radiation isnt going to give anywhere near enough cooling unfortunately. I can prolly go find some equations, but it would be hard to work it out with all the variables. Also remember that your HD is still in a plastic box, which is a poor conductor anyway.
Radiation relies on a high T. I think it might even be proportional to T^4.

PS: btw fyi ( )
convection - fluid currents
conduction - molecular interaction
radiation - electromagnetic transfer


PS2 (the edit) heres a link i found for black body radiation http://geosci.uchicago.edu/~archer/PS13 ... ermal.html

He probably means conduction cooling.

And I do think it could work, sorta. In order to get the heat conducted out of the HDD you'd have to have a heatsink (sidesinks perhaps) the penetrated the vacuum chamber. That way the heat could be conducted across the sink and out into the external air.

The problem with this is that the heatsink will also transfer the vibrations out to the air as well, completely defeating the purpose.



As for your question about the breathing hole. No, its not used for cooling. It's purpose is to allow for the equalization of the barametric pressure inside the drive to that outside. In a vacuum chamber the air inside the drive would just come out through the hole, eventually leaving the drive equalized again.

SungHyun7, I think that is a really really cool idea. Much applause from the inventors bench for originality. It won't be easy though...

• You will have to very carefully depressure the drive so that it's breather doesn't overload and pop. Also any air bubbles within the bearings (especially sleave/fluid types), will need to migrate away very slowly in order to not push oil out into the rest of the drive. See the Bell Jar, and the article Bubbles and Gel Candles, which talks about de-gassing and messes.
• Heat transfer by radiation relies on heat shining away as infra red light, which hopefully gets absorbed by something else and taken away. In outer space they have a damnable time loosing heat. They have to use refrigeration units to concentrate it, then special radiators that glow IR out into space and away. That's not going to work nearly well enough in your idea.
• If - you could get plastic flexible heat pipes (they are on the way), they might move heat out to external heat sinks, without conducting significant noise.

I think we'll have to live with Seagate's offerings for now, and at least they are not nearly so aweful as the past. It's too bad we cant just remote the CD's ad FDD's, and move the main box out to pasture somewhere, without adding big$$$ and complexity to our systems. Hopefully won't be long coming though.

A possible alternative:

• plain heatpipes are cheap these days - just maybe a bit tricky to get. Solder/clamp one or two pipes to a strip of plate copper that screws tightly with thermal compound, on each side of the hard drive. That way each side of hard drive has 1 or 2 well coupled heat pipes running a ways out back.
• Build a very thick acoustic foam/lead/foam/lead/foam/lead layering to catch all the sound. You can get the stuff as acoustic liner for engine rooms and such. Other materials could work well too. Wrap it and wrap it and wrap it.
• Now add cooling fins or water blocks or whatever to the back end of the heatpipes.
• Or easier still, do the same wrapping, but use water cooler plates directly on the HD sides, inside all that sound barrier, and run the hoses out.

To add to crisspy's suggestions, I'd suggest you go to the link in another thread: http://forums.silentpcreview.com/forums/viewtopic.php?t=2312

That dude in Japan has got some crazy cool ideas on quieting his HD's. Silicone caulking/plastic wrap/rubber/aluminum sandwich? omigosh!

(edit) PS: I'm a little too chicken to try the caulking idea for now. I still need to experiment with 1" rebond foam/suspension first.

mmm...

my first guinea pig = IBM 75GXP 7200rpm 40gb HDD

experiment date = possibly 11-16-02 (or i can wait until seagate v comes out)

preliminary experiment protocol:
1. aluminum heatsink made out of 2mm thick (hopefully i'll find one with some ridges). this will be added directly to my hard drive with no pad in the middle. i'll put it on the back of the drive, not onto the circuit board to avoid shorting. will drill a hole for that 'breathing hole' of the drive.
2. my suspension idea:
get four long screws that i'll attach to the side of the hard drive (where the short screws normally affix the drive to the case). and i'll tie my elastic ropes to those screws.
3. vacuum chamber:
reinforced lay's bulls bbq potatoe chip bag ($2.99, and you get a free snack) . reinforcement will be made out of few of my metal chopsticks i've been saving in the last kitchen drawer just for this occasion.
4. cables:
attach normally then carefully make a hole in the potatoe chip bag which I'll seal very well with heavy duty tapes. when everything's complete before creating the vacuum, i'll cover the whole bag with the duct tape couple times.
5. the vacuum:
i bought one of those closet savers. you put clothes in it, then you vacuum out the air with a regular vacuum cleaner to compress the clothes. that's the only option i got... so if it's going to be too quick, well, i got no choice.

well my guess is, the drive will overheat and die on me in minutes if not seconds. heatpipe idea sounds good, but i don't have soldering iron to implement it. my actual intension is just to set some precedence for a very few of you to follow, and hopefully a few of those will suceed in the future.

this is an overkill, but i believe it is a necessity if you really want a dead silent drive that'll work unless you want to shell out $3000 for a solid state drive.

only issue is heat... (and possibly that breathing hole)... you have no air to the dissipate heat by the conventional convection method. plastic heatpipe sounds good, and i'll think about it in the near future (proven they work).

It's your biggest issue. If you actually manage to create a vaccuum, the drive will probably cook in 5 mins or less. EVERYthing thermal assumes at least air convection for cooling. No air & no conduction path means the heat simply builds up.

How about A firewire/usb 2 drive and a long cable? Put it in the basement or closet...Cable length is not really an issue if you use repeaters (I think thats what theyre called)

maybe it's best if i best for those plastic heatpipes... yea it sounds like sure thing that drive will fail. i can't imagine radiation alone will dissipate nearly enough heat from the drive.

Sorry to rain on your parade, but you ain't gonna get the vacuum you need to block sound like that. For a much easier experiment than a HD, try using a small battery alarm clock. Set it for 5 Min later. Put it in a rigid container. Vacuum seal it up, no wires to go wrong. Now, when it rings listen to the volume, then cut the seal. Does it get louder? How much?

Some small air conditioners have vacuum pumps that might get you close. See Vacuum Basics from the Bell Jar.

Serial ATA lets you go up to 1M or 1.2M (?) with quite thin & relatively flexible data and power cables (yes, they are separate). With that much length to work with, you can easily build a dedicated muffled hard drive box (with as much cooling as you can devise) that sits outside the main PC. Inside the dedicated drive box, you could suspend, sidesink, heatpipe -- basically, anything you want because you're not restricted in terms of size, form factor or what have you. All you have to do is make sure the cable will reach.

With reasonably intelligent design and execution, such a box would let you use whatever drive you want -- the noisiest biggest fastest SATA-based RAID drive setup could be silenced in a box like this.

good points. i'll try the alarm clock method and evaluate my experiment again. it's never going to be a perfect vacuum with my method due to the lag time between getting the vacuum hose off and putting the cap on. ah wells... it was fun while it lasted... at least for me. i plan to get the aluminum plate anyway and will try to copy one of the sandwiches in the mod section. basically as i understand it, it's sponge pad/aluminum plate on the circuit board side, aluminum on the other side, bolt the two plates together, sponge the sides, and that's it right? i'll suspend it right in front of my intake duct. sounds simple enough. 2mm seems to the thickness we all agree on for ideal heat conduction. and i'm guessing the breathing hole obstruction by one of the aluminum plates shouldn't concern me.

well, change of plans then

by the way, what is the breathing pole's function anyway? if it for simple cooling? or for something i wouldn't want to spend the time to get to know? most drives come with big warning saying, do NOT cover this hole like the drive's going to explode if i do.. i'm just curious.

The last few hard drive that I have got I haven't managed to find the breather holes on them though... what does this mean guys?

Could be hiding out underneath, behind the cct. board. One never knows without a giga sacrifice. Seriously, the thing's surely gotta have one. Or could they really be that well sealed?

with the breather holes that I saw on the old HDD's though they have big warning stickers not to block those holes....... no idea actually... wondering whenever or not I can seal a HDD in RTV Silicon.. and mount it into a Al enclosure box..... I decided to use RTV silicon cause,
- it conducts heat
- not electricity
- rubberised silicon so vibration decoupling
- would look pretty sweet with blue LEDS inside this setup cause RTV Silicon is translucent
- give VERY good shock absorbtion

oh yeah and I was looking for a crazy mod to do
that japanese guy inspired me

Just my humble thought... isn't this whole discussion useless?

I've always been thinking that the heads rely on 'air' to float on the disks
when they're spinning, meaning they would crash in vacuum.

Someone out there with other opinons? (surely )

duh... ummm... .

Of course you are absolutely right gommer, the heads fly on the air current. I knew that too. Thanks for having a brain.

However, I just also remembered that IBM Microdrives are vacuum compatible. They have been used in outer space by NASA astronauts for digicam work, if I remember correctly. I think I saw it in an ad somewhere. I wonder how they do it. Maybe at that small size they had to suspend the heads b/c the air layer wouldn't do the job. Or maybe they are sealed, which wouldn't be a bad plan for something that is expected to be mobile and often live in wet/dirty environments. 14.7psi (or more) is not a lot to hold inside a small enclosure like that.

Any which way, I expect that normal large harddrives would quickly crash and burn given very much thinning of the air. Even airplanes are dramatically affected by air density, both for prop efficiency and wing lift capability. If the air was just a bit too thin to counter the head suspension, both heads and platters would grind very quickly.

Still SungHyun7, if you do the alarm clock experiment let us know. May be we could run our fans in a vacuum . Just joking, really. We all get a little egg on our faces now and then trying to work the bleeding edge for new angles on old problems.

oops again,

IBM Microdrives have a breather hole, I'm not sure they are vacuum compatible. They say they work in zero gravity environments, but don't mention vacuum. Was probably only used inside. Oh well.

I guess the Vacuum idea was to silence the drives if so just replace all your hdd's with Seagate IV's, and sell any noisy ones while they are still worth some money.

Unless you have a near silent system you wont hear the Seagate's. As the hdd's are the only noise producing item in my system I do want to silence them completely so I can finally call it true silent. I have them effectively cooled by a water block and intend to isolate them in a double glassed box, suspended by anti vibration mounts. Will probably do it in Perspex initially as it's easier to work with, but if it's not good enough I'll then try Glass. Double glassing can be extremely effective at reducing unwanted noise, and special types are often used in houses and offices that are near very busy roads or airports

Probably the only way to go truly silent is to have zero moving parts. Solid state storage is by its very nature silent. (and will work in a vacuum too )

I saw a press release from Pretec that they're going to be releasing 3 Gig Compact Flash Memory cards. http://www.pretec.com/default.htm


But, if you have to ask the price, you proably can't afford it. ($2499 for the 3 gig)

Actually, this has been in the digital camera forums since the Microdrive was released, since it stated in the FAQ's/data from IBM that it had a 10,000 foot altitude ceiling. Some have exceeded this with success though, so I'm sure it's more of an air pressure issue, since the heads "float" on a cushion of air and if there isn't enough, then they crash into the disk surface.

Here's some recent linkage:
http://forums.dpreview.com/forums/read. ... ge=3905566

So, I'd say that a hard drive would not last very long in a complete vacuum. But, if you had said hard drive contained in a container that was surrounded by vacuum, except a vent tube that led to the back of the computer, that should significantly reduce sound. I'd use something of about 1/4" diameter and make sure it never kinked. Of course, the place that the tube left the surrounding vacuum chamber would have to be cushioned to prevent noise transmission, also.


Good luck. =)

It would need to be a strong casing on the hard drive to handle that. You would have an internal pressure of approx. 15psi inside the drive, and approx 0psi outside. IBM MicroBalloonDrive. Seagate Ballacooda. Maxtor SphereMax...

I don't think the whole vaccuum idea will fly. Too many obstacles.

There are simpler, cheaper effective solutions already.

If the vaccuum is being used only to silence and not destroy the drive (which may be a side effect), Why does the drive need to be englufed in a vaccuum? Doesn't it just mean that it needs to be surrounded by a vaccuum?

So what we need is a wide, high-end thermos... the kind they use to keep soup hot. We also need some very, very effective rails coming out of the other side and maybe a 5v panaflo. Maybe a Pizoelectric cooler and a big heat sink?

The sound wouldn't be completely self-contained, but would be shielded from going forwards in the case. Wrap the corners of the drive in foam to prevent vibration transmission, aim the can at something likely to break up the soundwaves (like a video card), and enjoy the ride.

Ideas? Anyone in Boston have a thermos?

-C

Yea, the vaccum idea would probably be too complex and bulky to be worth while.

What I would like to have is a small enough electronic noise cancellation device, that would fit inside the pc, be omni-directional, so it could cancel out all of the fan noise.

An electronic noise cancellation device is basically a microphone, computer and speaker that recieves noise, then transmits back, almost instantaniously, an exact copy of the incoming noise, only 180 degrees out of phase, which cancels out the noise.

Right now, though, it would probably cost more than your computer...

Actually CRT_Leech, I've been thinking about this idea for a while now.

In theory it wouldn't be that complicated: Since fan noise is of a constant frequency all you'd need is a DSP plugin to convert the noise 180 degrees out of phase. Your computer already has the hardware it needs; a soundcard with a line in for the mic's and a line out for the playback speakers.


But in reality its alot more complicated. The fan noise comes from too big a source to be damped by 1 speaker. You'd need an array of mic's and speakers working together. The system would require individual tuning based on its particular environment, and that tuning would be much more sensitive than what a hobbiest could do. Even the slightest imperfection in the sound wave interferences and instead of reducing the noise you make it twice as loud.

Somewhere I ran across a java app online that sends 1 frequency to your left speaker, and the inverse to your right. If you put the 2 within an inch of each other there was silence, but move 1 even a tiny bit and it got really loud.


One way this could be made to work would be to put the mic, speaker, and processing chip all inside the hub of the fan. By being within the source of the noise 1 speaker could cancel it out by itself. Of course this would require some seriously tiny electronics, and would probably result in a fan that costs $500 each.

Hey Rusty, we need a new thread outside of the dead vaccuum topic if we're going to start talking noise cancellation. I think it's a very feasible idea for the right applications, and well deserves a good going over by the crew in here. How about we should start a new thread under the fans topic?