Heat pipe coolers

[jim5000]

Was just reading some reviews of coolers and something struck me about heatpipes. It seems they basically work on the principle that the coolant evaporates in the pipe and rises to the top where the fans and heatsink are.

But as most people have towers the heatsink is mounted horizontally and the heat pipes dont actually point up, so the warm liquid\gas of the coolant isn't all going to naturally gravitate towards the fans, which is kinda the point of them?

 

[Glaucus]

I think they are driven by thermal differences and not mavity. So it doesn't matter what orientation they are placed at.

 

[Glaucus]

commercially available heat pipes do not rely on mavity alone to move the liquid back to the heat source; they take advantage of capillary action. The inside of the heat pipe tube is filled with a capillary structure, often referred to as wick.

 

[jim5000]

ah, ok

 

[cmndr_andi]

The coolant far away from the heat source is cooler and thus higher density when compared to the coolant next to the heat source which is high temperature, low density. Therefore there is a pressure gradient setup which pulls the high temp, low density coolant away from the heatsource and up the heatpipe, being replaced by low temp coolant. Hence a convenction current is setup.

Yay for secondary school chemistry

Edit: Or what acidhell said

 

[Audigex]

Layman's terms - physics does stuff which stops it mattering.

Slightly less layman - increasing pressure from it evaporating makes it go up the pipe where it condenses in the lower-pressure, lower temperature end. Capillary action makes is go back down again.

It's actually the evaporating that does the cooling rather than water flowing over it - like sweat, rather than a cold shower.

 

[shadowscotland]

Thats all true but mavity is a factor and all things being equal a TRUE in a tower on it's side is more efficient than the same case standing up (as designed) might only be a degree or two but its a factor