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Posted: Mon Mar 22, 2010 12:33 am
by jackssmirkingrevenge
POLAND_SPUD wrote:yeah time to use materials you have lying around
now seriosuly... you might try it but I doubt it will work good
It would be easy to make something like this with sutable spacers:

Posted: Mon Mar 22, 2010 12:35 am
by MrCrowley
Friggin' Heck Jack!
As you can see, the toolbox can't accommodate 3 fans on the side, perhaps I can place the two 80mm fans at the same end as the 120mm but one on the front and one on the back of the toolbox. May as well just buy a whole new toolbox though
Tomorrow I'll swap the fans around but leave them where they are, if I'm not satisfied with the cooling I'll think about a new prototype haha.
Posted: Mon Mar 22, 2010 12:56 am
by POLAND_SPUD
....or you can get a larger fan instead... like 10X the power you have now...
you can't go wrong with an overkill
that would simplify things a lot.. just one fan, less wires, and only two holes to cut (one for the fan and one vent)
Posted: Mon Mar 22, 2010 1:17 am
by jackssmirkingrevenge
MrCrowley wrote:As you can see, the toolbox can't accommodate 3 fans on the side, perhaps I can place the two 80mm fans at the same end as the 120mm but one on the front and one on the back of the toolbox.
It doesn't have to, you want the two smaller fans opposite the larger fan:
---->smaller fans [compressor] big fan ---->
The larger fan probably puts in more air than the small ones combined, so better to have it pulling out to avoid an overpressure inside.
Posted: Mon Mar 22, 2010 2:21 am
by spudamine
Everybody seems to be saying the fans are put to best use sucking air out rather than blowing it in. So how come every piece of fan cooled consumer equipment I've ever seen has fans blowing air in with the warmer air flowing out through vents?(eg. any computer).
I think the idea is to blow a stream of air over the object being cooled to remove the warm air which builds up around it. Sucking the air away from around the pump wil not be as effective, air blown out by a fan is in a focused narrow 'jet' whereas air taken in is a much wider but weaker cone.
I would off thought your original design was probably as good as it's going to get without some additional heat sinking.
Posted: Mon Mar 22, 2010 2:46 am
by MrCrowley
Looking in to it on Wikipedia...
http://en.wikipedia.org/wiki/File:Compu ... r_flow.png
Desktop computers typically use one or more fans for heat management. Almost all desktop power supplies have at least one fan to exhaust air from the case. Most manufacturers recommend bringing cool, fresh air in at the bottom front of the case, and exhausting warm air from the top rear.
If there is more air being forced into the system than being pumped out (due to an imbalance in the number of fans), this is referred to as a "positive" airflow, as the pressure inside the unit would be higher than outside. A balanced or neutral airflow is the most efficient[citation needed], although a slightly positive airflow results in less dust build up if dust filters are used. Negative pressure inside the case can create problems such as clogged optical drives due to sucking in air (and dust).
It sounds like it would be better if I closed off the two ports where the 80mm fans are, have them placed at the top sucking air out and leave the 120mm fan where it is blowing air in...
edit:
What about undervolting? This thing is turning more and more in to some 14 year old case modder's wet dream...just need some neons or LED's

Posted: Mon Mar 22, 2010 2:56 am
by spudamine
It sounds like it would be better if I closed off the two ports where the 80mm fans are, have them placed at the top sucking air out and leave the 120mm fan where it is blowing air in...
Sounds like the best plan.
What about undervolting? This thing is turning more and more in to some 14 year old case modder's wet dream...just need some neons or LED's
I think you would want overvolting

Posted: Mon Mar 22, 2010 3:01 am
by MrCrowley
Now i'm thinking; 120mm fan where it is (blowing air in), 80mm fan opposite end sucking air out and 80mm fan at the top vent closer to the opposite end of the 120mm fan sucking air out. Theory being that air from the 120mm fan will hit the compressor and want to go up.
Posted: Mon Mar 22, 2010 3:17 am
by Technician1002
In the work I have done with high power electronics (televion transmitters) the best thermal design I have seen is to prevent heat build up around sensitve components. Instead of blowing cold air on the hot components and blowing the warm air through the rest of the equipment, the best bet seems to have plenty of positive air into the cold areas of the equipment to keep them cold, then taking that air past the hot components such as the CPU hard drive, memory, and graphics chip and directly venting the heated air out using negative flow so the heat can't leak back. Having a hot box of stirred hot air does not help the components keep cool. CPU fans, graphics fans and such should vent diretly out of the case in good thermal management.
With high power used in overclocked machines simply sticking a fan on it is not the best solution. Venting the heat out of the box is.
Posted: Mon Mar 22, 2010 3:17 am
by jackssmirkingrevenge
I think the fans should be inline for smooth airflow, think pneumatic efficiency

any chance of mounting it directly below the compressor? Toolbox/pasta strainer

Posted: Mon Mar 22, 2010 3:25 am
by Crna Legija
by the end of this you would have water proofed it and dunked it in a tub of water
Posted: Mon Mar 22, 2010 3:26 am
by MrCrowley
I think the fans should be inline for smooth airflow, think pneumatic efficiency
With a compressor in the way it's like
fighting your way through a hallway of bad guys with only a hammer
Mounting directly below the compressor is a possibility but you run in to flow issues and from memory the bottom of the compressor doesn't heat up very much.
the best bet seems to have plenty of positive air into the cold areas of the equipment to keep them cold, then taking that air past the hot components such as the CPU hard drive, memory, and graphics chip and directly venting the heated air out using negative flow so the heat can't leak back.
So like what JSR and the others recommended? In that case, would it better to go streamlined, like JSR mentioned, or to have some negative flow out the top too?
edit:
by the end of this you would have water proofed it and dunked it in a tub of water
Or back where it came from...inside a fridge

Posted: Mon Mar 22, 2010 3:30 am
by POLAND_SPUD
to what extent increase in flow affects cooling rate ?? just check CFM of small computer fans and other, slightly more powerful fans.. it isn't that difficult to get much higher flow
Posted: Mon Mar 22, 2010 3:32 am
by MrCrowley
From what I read, CFM is the most important when it comes to computer fan cooling (in terms of the actual fan, not placement).
Posted: Mon Mar 22, 2010 3:45 am
by POLAND_SPUD
this...has mere 100 cubic m/h of flow
while
this thing....410cubic m/h of flow
and
this almost 5700 cubic m/h
get my point ??

there are other things than cooling that are more important... probably 80-90% of the time you won't run the compressor long enough for it to get hot... if you had a large tank it would make sense... but I don't think it's the best idea to waste time how to optimize flow through the tool box or how to build a ghetto radiator if you can simply use a more powerful fan