Loop Heat Pipes

[HotFoot]

I think most people will agree that for air cooling, heat pipes have become pretty standard equipment, at least in after-market heatsinks. The type of heat pipes I've seen used are all pretty basic: a hollow metal tube, usually with a wick built in. Liquid evaporates to absorb heat at the source (CPU side) and condenses to release it's heat at the opposite end. The condensate then moves back to the CPU through the wick via capillary action. Simple enough.

That's your basic heat pipe as far as I understand it. However, there are much more advanced types, such as loop heat pipes (LHP). These are used in satellites to cool electronics. The principle of the LHP is similar tot he basic model, except that the wicking action travels along a separate line back to the hot end. This separates the hot vapour and cooler liquid phases, and allows for much greater cooling efficiency.

I figured a LHP cooler would probably fit into the extreme cooling category. Certainly I can imagine an LHP costing less than a TEC, and a nice feature is that they can be self-starting with temperature differences of less than 20 C, with no moving parts. However, I haven't seen any CPU coolers for sale with LHP technology. Do any of you Forum members know of one? I would be very interested in trying one out to compare with my conventional heat pipe cooler.

 

[HotFoot]

I get that standard HP tech is great. My cooler has 3 HP's and it was pretty cheap. However, when you're looking for maximum cooling to a concentrated heat source, some people are willing to pay the premium for fancy gear. This is why we see people building $500 liquid cooling systems and then throwing in an extra couple hundred for a TEC. Any idea what a LHP for a CPU cooler would actually cost if it were commercialised?

 

[tool_462]

I don't know much about loop heat pipes, but it wouldn't be more dependent on orientation (vertical/horizontal/upside down) would it? I know if you turn a normal HSF with heat pipes upside down the temp actually does rise, I've tried it. Except my NB HP doesnt change, probably because it is empty as I thought it was and is more for looks and simply being copper is the only thing that moves heat from the NB to the little radiator in the corner of my mobo.

 

[tool_462]

Apparently Arctic Cooling Freezer 7 Pro's dont have good heat pipes then. I really should crack open a heat pipe and see whats going on inside. Is there any free flowing liquid or just enough to soak a wick for capillary action to take effect?

Wonder if there is any data as to how much heat the liquid carries and how much heat the copper carries.

 

[tool_462]

Cool, nice article.

I assume the liquid within most PC heatpipes is something along the lines of acetone/ethanol.