Heat Pipe coolers, Horizontal or Vertical mounting ?

It seems like the top performers CPU cooler uses this type of tech these days and many claim to be even better than a basic Water system.

The basis of HP'S: Heat pipes work on the principle of evaporation and condensation. A working fluid (frequently distilled water) evaporates inside one end of the heat pipe (the hot-end) absorbing heat in the process. A partial vacuum inside the heat pipe allows the water to evaporate at low temperatures. Once formed, the water vapor diffuses from an area of high vapor pressure (where it is being generated) to the other end of the tube where the vapor pressure is lower.

The vaporized fluid then condenses back to liquid (cold-end) and the heat is dissipated into the air from the metal cooling fins. The working fluid returns to the hot end via capillary action thru an internal wicking structure (sintered metal coating, fine wire mesh, or grooves) so the heat pipe does not have to rely on gravity to recycle the working fluid. The key to a heat pipe’s high efficiency is the latent heat of vaporization.




I've read a few reviews and all af them seem to be made on a "test bed", outside a case and placed horizontally.

Since the principal of HP's is base in liquid evaporation, and liquids are affected by gravity my doub is:

How efficient an HP's cooler becames, or how much efficiency it looses ( if any ) when placed Horizontally?

Does it really make a difference ?

Thank you.

yes gravity makes a difference, but the heatpipes also use capillary action.

http://www.heatsink-guide.com/conten...eatpipes.shtml

That's why the ASETek vapochills have to be turned a certain way when mounting them.