linear tube in tube HE

[mejunkhound]

Cannot recall which thread I was going to put this in, so will post as a general thread.

Rather than a coil, my 5 T water to R22 (or R290) evaporator is simply tying a bunch of coaxial pipe together.

Pic or HE attached to ceiling of basement, with proper slope for refrigerant oil.

Also pic of assembly with spiral 1/4 tube (or even poly rope would work) to get better heat transfer. Note the inner 3/4 Cu tube was radially sanded with 36 grit to further increase turbulence and hence enhance het transfer.

Transition to outer water jacket by simple expedient of casting epoxy seal in side old green bean or OJ cans.

[superlen]

Thanks for posting pics of this & details.

[TechShop]

I like it. There is no reason you have to coil or helix your HX.

I was thinking about your epoxy end fittings. If you wanted to make them serviceable, you could use a standard water tight cord grip or cable gland from the electrical industry. They have plastic and metal versions and they are available with a rubber seal / bushing in the water tight versions. Also, they use standard pipe thread sizes.






Liquid-tite style conduit may be useful in these applications also.

[jeff5may]

Originally Posted by TechShop

I like it. There is no reason you have to coil or helix your HX.

I was thinking about your epoxy end fittings. If you wanted to make them serviceable, you could use a standard water tight cord grip or cable gland from the electrical industry. They have plastic and metal versions and they are available with a rubber seal / bushing in the water tight versions. Also, they use standard pipe thread sizes.






Liquid-tite style conduit may be useful in these applications also.

Don't do it, man! Those fittings don't even work well for drain lines. I have seen many a buddy tempted by the appeal of such cheap, common hardware. A simple rubber grommet around a barb fitting holds up better.

For better ideas, look up shotgun condenser homebrew rigs. Even the hillbillies can come up with better. LM and VM condensing is a bit more refined, but even they have terms like "the dephlegmator".

Not trying to flame you or nothing. Just an urgent warning. I have seen people flood their basements trying to use liquid tight fittings. They tend to fail unexpectedly while you are away. Kind of like the silicone caulk that says "not for aquariums" on the label.

[TechShop]

No offense taken.

I haven't used those parts in this application, so if your experience with them is that they fail, I believe it.

[MEMPHIS91]

Awesome info mejunkhound! Thanks for posting! I wish I had a basement to do this in!

[digiz]

30 days demo.
Design of coiled double-pipe heat exchangers / coaxial tube heat exchangers (KOAX)
lv-soft.com

Here are some calculations.

[digiz]

too small pictures