Putting ANYTHING through a phase change is not efficant. You're best off with a pump. even if you did go with boiling the water, to keep that process efficant you'd need to do something to recover the heat you put into boiling it... that's going to require coolant and pumps as well.. (thinks about it) or a well primed system so a siphon effect would hual water through the heat exchanger.
IT comes down to, unless you have a LOT of waste heat, boiling water is not efficant.
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Truth is a complex thing. One must govern by simplicity. -M. Mercier, special counsel to his Majesty for domestic matters. The Brotherhood of the Wolf
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