Quote:When the tiny hole let outside air into the vacuum.. even though no liquid leaked out.. the boiling point went back to 100c. At a guess vacuum puts boiling point at about 30c so it starts piping heat away.
Heat pipes are vacuum sealed pipes with a small amount of liquid, usually distilled water, this is under low pressure to bring down the boiling point. The inside of the pipe is lined with a layer that acts as a wick, a woven wire mesh or sintered copper. The water boils at the source of the heat (CPU), the gas diffuses to the cooler ends of the pipes where it condenses into the wick and capillary action takes it back to the site of the heat again.
People often say "I don't think my cooler is working properly. The top of my cooler isn't even warm to the touch. Well, for heat pipes to work properly one end of the pipes has to be cool and one end hot or it won't work. So of course the top of a cooler is cool.