CPU coolers use a heatpipe design that uses liquid that turns into a vapor in their heatpipes that evaporates and condenses to move heat up the pipe.
In my system I cracked a pipe slightly. I don’t think it’s leaking but it may with further damage. So I was wondering what the pipes are filled with and if they pose a toxic risk if they leak out.
A variety of fluids (ammonia, acetone, ether) may be used in general for heatpipes, but for a home PC, it’s more likely just distilled water, alcohol or a water/alcohol mixture.
Found a member on the Anandtech forums that emailed Arctic Cooling and asked them what they put in their heatpipes.
From what I’ve been reading, most consumer PC heatpipes just use distilled water or perhaps ethanol.
The heat pipes I saw many moons ago used alcohol (perhaps ethanol) as a medium. The low evaporation point allowed the hot end to absorb more heat.
Aha, sounds harmless enough then.
Had a weird sequence of events where I accidentally bumped my computer case, which made it fail to boot up - probably a short because the backplate on the heatsink is improperly spaced - so I took it apart to check it, fiddled with it, got it to POST, but then got a vague burning smell coming out of it and my throat became very irritated, so I was worried that I’d somehow let something toxic out of the heatsink. Now I have no idea what the deal was, but it sounds like whatever it was, it couldn’t have been anything from the heat pipes.
even water is used…
Heatpipes are typically under a vacuum to get the fluid to vaporize at a lower temp than the normal boiling point (i.e. near where the processor’s supposed to run at), and water would work just fine.
That being said, if you think there’s a leak, you ought to replace it- letting air in would break the phase-change part of the heatpipe.
I don’t think this quite captures the strategy. I think heatpipes generally only have the one substance in them, for example water. If you pour water into a length of tubing and seal the ends, and trap air in there too, then water has to diffuse through the air to travel around, and the pipe is not much good. You want nothing but water in there, so that water can evaporate at one end, blow down the length of the pipe, and condense at the other. Since you can’t condense air at the far end, having any air in there would bring the water vapor flow nearly to a stop.
Besides, heat pipes can work at any temperature between the triple point and the critical point. The normal boiling point doesn’t matter.