On Sun, 13 May 2012 10:16:58 -0500, dpb wrote:

On 5/13/2012 9:25 AM, Steve B wrote:
...

maybe like 4" outer 2" inner, and half inch tubing. Just have to make a
chart on ID's and OD's and see what looks like the best fit.


Seems to me the starting place would be to decide on necessary flow
rates and then the required velocities to achieve same w/ a given
annulus size and resulting friction losses, etc., etc., etc., ...

Then when have the design reqm'ts the pipe sizes will fall out as what
they must be (or the concept will be shown to be flawed/feasible).

Aaaaand consider that there are alternate sizes - in Copper hard pipe
and soft tubing there's a second whole series besides L and M water
pipe, Refrigeration copper is thicker wall and higher pressure, comes
cleaned nitrogen purged and plugged at the ends - and has intermediate
sizes available that water pipe doesn't.

1/2" ID water pipe is 5/8" OD refrigeration, 3/4" ID is 7/8" OD, 1" ID
is 1-1/8 OD - that all crosses, and the fittings interchange.

But ACR refrigerant line goes down to 1/4" OD flexible, 3/8" OD hard,
and up to 1-5/8" OD flexible and 3-1/8" hard. And 20-foot lifts are
the standard, so you don't have as many joints to braze (or leak...)
in a big refrigeration install.

If you use copper, remember vibration flexing will crack it - you will
want to rig up spacers for the annular space to keep it either
centered or pushed off to one side and steady.

-- Bruce --