Jim Dunmyer said the following to Mike Ross on the subject of
RE: POWER SOURCE/PUMP (25 Jan 98  10:53:48)
 > It can be a 1 pipe or 2 pipe system. The 1 pipe type must have a larger
 > gauge because the hot and cold water create opposing flows in the same
 > pipe. A 2 pipe type only has flow in 1 direction so the gauge can be
 > smaller.
 JD> I've heard of single-pipe STEAM heating systems, but never a
 JD> single-pipe HOT WATER operation. The steam is pretty simple, they use
 JD> fairly large pipe, sloped down to the boiler. The hot steam rises,
 JD> condenses in the radiator, and the condensate (a small fraction of the
 JD> volume of the steam) runs back down the pipe to the boiler.
 JD> Are you SURE you've seen or heard of single-pipe hot water heating
 JD> systems?
I only read that a gravity hot water system could be 1 or 2 pipe. A 1
pipe steam system is pretty obvious as you described it but it's not as
clear with gravity hot water. I'm guessing, that if one pictures a pipe
as wide as the heated tank, without doubt the water will still convect
in such a pipe though certainly not nearly as well as a 2 pipe system.
The system would need a larger main pipe and require a minimum amount
slope for it to work. The radiators would tap off the top of the main
pipe for the hot side and return to the bottom of the main pipe on the
lower slope. As I wrote, this just a guess because I've never seen it
either but it doesn't seem too outrageous either.
Thanks for making me think!
... Ice Storm of the Century refugee.
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