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post #11 of 15
OK, well now what you're describing is a thermosyphon (also called gravity loop heat pipe). Just like a wick heat pipe, except no wick so they must be oriented ad you have shown so that gravity can return the condensed liquid to the evaoprator. They work just fine, comparable to other heat pipes depending on working fluid and construction of the heat exchange surfaces. Water is a terrible working fluid... Refrigerants are normally used, in particular acetone.
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post #12 of 15
Quote:
Originally Posted by DetroitAC View Post

OK, well now what you're describing is a thermosyphon (also called gravity loop heat pipe). Just like a wick heat pipe, except no wick so they must be oriented ad you have shown so that gravity can return the condensed liquid to the evaoprator. They work just fine, comparable to other heat pipes depending on working fluid and construction of the heat exchange surfaces. Water is a terrible working fluid... Refrigerants are normally used, in particular acetone.

Ok..so..I'm feeling that filling a copper pipe with acetone..then trying to seal it up with heat...aka flame..before you blow
your face off would not be a good idea :thinking.gif: A pinhole leak could make it a bomb.
 
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post #13 of 15
Quote:
Originally Posted by Schmuckley View Post

Ok..so..I'm feeling that filling a copper pipe with acetone..then trying to seal it up with heat...aka flame..before you blow
your face off would not be a good idea :thinking.gif: A pinhole leak could make it a bomb.

Naw, there are plenty of techniques to safely fill a closed system with a hydrocarbon. These are all practical refrigeration techniques, like install a service valve in a brazed assembly, or braze the assembly and then fill via a small tube, pinch it off and braze it. It's done all the time
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post #14 of 15
Thread Starter 
Why is water a bad working fluid in this particular arrangement? Latent heat of vaporization too high? Ideally the whole loop is at the same temperature, which is why I thought specific heat was more important.

Whenever I get around to building it I suppose I could test different working fluids.
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post #15 of 15
It's an engineering field of it's own, very complicated and I won't pretend to know very much.. BUT, gas phase density is very low. I'm not going to perform the calculations, but my guess is you need pipes ~5x bigger to transport gas phase with water. I know this is the case with water based refrigeration, gas side machinery has to be huge because of low density. Look it up on Google, consumer electronics heat pipes generally use Acetone as the working fluid.
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