[Beowulf] Desktop fan reccommendation

[Vincent Diepeveen]

This is all huge decibel junk man.
So any centrifugal fan is out of the question if it produces that  
much noise right next to my desk :)

In general spoken i don't understand why so many persons accept from  
manufacturers those huge soundlevels.

The fans i got here, the 18 CM ones are 700 RPM @ 19 decibel, you  
don't hear them.
The 1500 RPM aerocools 12 CM, you do hear them, but with their own  
rubbers and 1.5 meters away it's acceptable noise,
though it depends upon the heatsinks you got a lot and i had to buy  
some floor isolating material that absorbs a lot of decibels,
to quiet down things more.

Requirement 1 is : it must be low noise of course.

Would be very bad to have something of 60-100 decibel next to  
professional sound equipment.


On Jun 6, 2012, at 10:07 PM, Lux, Jim (337C) wrote:

>
>
>
> -----Original Message-----
> From: Vincent Diepeveen [mailto:diep at xs4all.nl]
> Sent: Wednesday, June 06, 2012 10:46 AM
> To: Lux, Jim (337C)
> Cc: Daniel.Pfenniger at unige.ch; holway at th.physik.uni-frankfurt.de;  
> Beowulf Mailing List
> Subject: Re: [Beowulf] Desktop fan reccommendation
>
>
> On Jun 6, 2012, at 7:28 PM, Lux, Jim (337C) wrote:
>> And a lot of higher performance PCs (like the Dell sitting on my
>> desk) use centrifugal fans (with variable speed, to boot)
>>
>
> When i googled on centrifugal fans, i saw huge prices in the hundreds
> of dollars.
>
> Would mean the centrifugal fans are more expensive than the entire
> cluster which seems a tad odd.
>
> So it's gonna be the cheapskate cardboard solution with some duct
> tape and glue and relative cheap fans.
>
> ---
>
> The fan in my dell is plastic and cheap.. I've seen them surplus  
> for under $5..
>
> But what you want is often sold as a "squirrel cage blower"..
>
> The advantages are:
> a) good performance against backpressure
> b) lots of very small blades, so the "blade repetition rate" noise  
> is high frequency, low amplitude and easily absorbed
> c) they give decent performance at low rotation rates (500-1000 RPM)
>
> they are the dominant device used in, for instance, heating and  
> airconditioning.
>
> A good cheap source is from automotive scrap yards.  The blower  
> that pushes the air through the heater core and all the various  
> ducts in a car is well suited to pushing a lot of air through a lot  
> of loss.  12VDC typically.  Make sure you get the housing too, not  
> just the squirrel cage and motor. This may require a bit of  
> hacksawing on modern cars.
>
> Ones from upscale cars are quieter than more downscale cars.  So  
> find that Mercedes scrap, not the stuff from the DDR (Do Trabants  
> even have heaters, or do you wear your good socialist overcoat)
>
>
> Here's a typical item on eBay
> http://www.ebay.com/itm/Squirrel-Cage-Shaded-Pole-Blower-Fan-220- 
> CFM-Dayton-60-available-/190685633240? 
> pt=LH_DefaultDomain_0&hash=item2c65bfdad8
>
> Here's a 12VDC one
> http://www.ebay.com/itm/454-CFM-12-VOLT-DC-SPAL-007-A42-32D-3-SPEED- 
> CAB-FAN-BLOWER-16-1406-/270917027943? 
> _trksid=p4340.m1982&_trkparms=aid%3D555000%26algo%3DPW.CURRENT%26ao% 
> 3D1%26asc%3D10%26meid%3D8950398135996031222%26pid%3D100009%26prg% 
> 3D1005%26rk%3D1
>
>
> I've also seen somewhat larger versions of this as an appliance..  
> plastic housing, designed to be set on the floor to blow air for  
> cooling or helping to dry  recently mopped floors or wet carpets.
>
> Here's one from a computer
> http://www.surpluscenter.com/item.asp?item=16-1151&catname=electric
>
> I should point out that they make these in huge sizes (as in 1  
> million CFM) for applications like underground mine ventilation