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Bitcoin => Hardware => Topic started by: jeppe on November 08, 2014, 05:04:06 PM



Title: can anyone explain evaporative cooling system
Post by: jeppe on November 08, 2014, 05:04:06 PM
hi,
so im thinking about designing a new bitcoin shed for my farm as a project.
i have fell across this farm: http://www.thecoinsman.com/2014/08/bitcoin/inside-one-worlds-largest-bitcoin-mines/
and they are using a evaporative cooling system to cool there miners and i thought it was a cool idea however had some doubts.

The writer describes it as "durable paper product that looks like the wavy corrugated part on the inside of cardboard. Water is pumped to the top and flows down, and the fans blowing outwards on the other side create negative air pressure, drawing fresh air through the holes and cooling it." however i don't understand how they do it with all the moisture coming into the farm at night and from the system itself wouldn't  it damage the miners? how do the keep the moisture away from the rigs? Can  :-X explain this cooling system in more detail?
Thanks,
Jeppe


Title: Re: can anyone explain evaporative cooling system
Post by: wh00per on November 08, 2014, 05:05:36 PM


try this >> http://en.wikipedia.org/wiki/Evaporative_cooler  It's pretty easy ..


Title: Re: can anyone explain evaporative cooling system
Post by: jeppe on November 08, 2014, 05:40:36 PM
But how do they keep the moisture/humidity out from damaging the equipment??


Title: Re: can anyone explain evaporative cooling system
Post by: dogie on November 08, 2014, 06:20:10 PM
But how do they keep the moisture/humidity out from damaging the equipment??

<95% humidity isn't a danger to electronics, its only when you start getting fully saturated air that it begins to deposit droplets everywhere.


Title: Re: can anyone explain evaporative cooling system
Post by: klondike_bar on November 08, 2014, 11:30:03 PM
But how do they keep the moisture/humidity out from damaging the equipment??

hot surfaces = evaporation.
cold surfaces = condensation
miners and heatsinks are hot surfaces, so theres no water on them to cause shorts


Title: Re: can anyone explain evaporative cooling system
Post by: JessicaSe on November 08, 2014, 11:41:05 PM
Can anybody explain what is the different between evaporative cooling system as compare to water cooler fan?


Title: Re: can anyone explain evaporative cooling system
Post by: bee7 on November 09, 2014, 12:14:57 AM
This reading might be interesting: https://bitcointalk.org/index.php?topic=313087.0


Title: Re: can anyone explain evaporative cooling system
Post by: aosmith on November 09, 2014, 01:13:07 AM
Evaporative cooling relies on the amount of energy it takes to excite water from a liquid to a gaseous state.  If you increase the humidity by say, 10% that means you are actively moving water into a gaseous state.  This transition from liquid to gas requires energy, which lowers the temperature of the air.



Title: Re: can anyone explain evaporative cooling system
Post by: Photon939 on November 09, 2014, 02:32:42 AM
Can anybody explain what is the different between evaporative cooling system as compare to water cooler fan?

Common PC water cooling systems use a metal radiator to dissipate heat into the air, it's the same as a normal heatsink but you're using water to move the heat away from the source instead metal conduction directly to the dissipation surface.


Evaporative cooling makes use of the fact that it takes something like 970BTU to evaporate 1lb of water. If you have a large surface area covered with water and blow a fan over it, you get sensible temperature reduction from the energy taken to evaporate some of the water. It's much more efficient than a normal air conditioner but they don't get used much for air conditioning normally because it dumps a crapload of humidity in the air. Miners don't care so it can be an advantage.

Also evaporative cooling effectiveness is inversely proportional to the humidity of the outside air. If it's already humid as shit outside, you don't get much gain with an evaporative cooler. In the desert, they work great


Title: Re: can anyone explain evaporative cooling system
Post by: Medow on November 09, 2014, 09:06:22 AM
We use evaporative cooling on our house , and it use much less power around .75 kw per unit.

And as aosmith said, if you have dry air you gain more cooling power.

The evaporative cooling system used on that mining farm , is consist of two part the durable paper with continuous water above it and behind it there is a fan that suck the cold air come through that paper.


Title: Re: can anyone explain evaporative cooling system
Post by: mavericklm on November 09, 2014, 09:33:09 AM
swamp cooler


Title: Re: can anyone explain evaporative cooling system
Post by: antirack on November 10, 2014, 04:02:52 AM
But how do they keep the moisture/humidity out from damaging the equipment??

<95% humidity isn't a danger to electronics, its only when you start getting fully saturated air that it begins to deposit droplets everywhere.

Which caused some problems at Facebook a few years ago.

http://www.opencompute.org/blog/learning-lessons-at-the-prineville-data-center/

Automated systems, or simple weather changes on the outside (temperature during day and night, weather moving through) etc can cause problems, especially for power supplies.

The Chinese farms have these problems on the large scale, along with dirt and pollution. But of course difficult (for them) to tell if it's just crap quality of components or simple physics at work.


Title: Re: can anyone explain evaporative cooling system
Post by: BTCish on November 10, 2014, 05:15:40 AM
Evaporative cooling relies on the amount of energy it takes to excite water from a liquid to a gaseous state.  If you increase the humidity by say, 10% that means you are actively moving water into a gaseous state.  This transition from liquid to gas requires energy, which lowers the temperature of the air.



Thanks, this explains it pretty good.


Title: Re: can anyone explain evaporative cooling system
Post by: aurel57 on November 14, 2014, 10:05:01 AM
Legionnaires Disease


Title: Re: can anyone explain evaporative cooling system
Post by: xstr8guy on November 14, 2014, 10:15:36 AM
Don't bother with evaporative cooling unless you live in an extremely dry environment. It is a very efficient method of cooling only if you don't have high humidity. Otherwise it just raises humidity levels without adding any significant cooling effect.

I was very surprised to see evaporative cooling used in that private data center in Thailand that burned down. How did they think that would help with cooling at all?


Title: Re: can anyone explain evaporative cooling system
Post by: Medow on November 15, 2014, 01:29:24 PM
Don't bother with evaporative cooling unless you live in an extremely dry environment. It is a very efficient method of cooling only if you don't have high humidity. Otherwise it just raises humidity levels without adding any significant cooling effect.

I was very surprised to see evaporative cooling used in that private data center in Thailand that burned down. How did they think that would help with cooling at all?

It is because it was very cheap and it didn't take much electricity , and i think they may life in a dry area.