Fin Tube Heat Dump Questions

[DenaliChuck]

I need ~40' of 3/4" fin tube as a heat dump for my Tarm Solo 60. I have a 4' vertical rise from the Tarm to the ceiling and the pipe can run 12' along the ceiling of my shed roof that is a 4/12 pitch.

Two questions:

What is the best way to plumb the heat dump...should it be one 40' loop (12' up ceiling, 8' across (level),12' down and 8' across (level) or would it be better to run it 4' up, use a manifold to split it into four 10' runs going up the sloped ceiling to a return manifold and down to the boiler?

How do I make a non-45*, non-90* bend in 3/4" copper to go from a vertical pipe to follow the sloped ceiling. I thought about using two 90* elbows but this seems less than ideal since it seems like this would limit gravity flow in the loop.

Thanks for your advice!

DC

 

[Jim Post]

I struggled with where to locate my fin tube based heat dump for my Solo 30. I ended up mounting it vertically on the wall next to the boiler. When power is cut to the boiler a valve opens and lets the heated water circulate by gravity up to the top of the fin tubs (3 rows parallel piped) then down through the fin tube sections to the floor and back to the return line of the boiler. It works fine.

jp

 

[Chris S]

Swing fittings
a 90 and a street 90, or 2 90s and a short piece of pipe. will give you any angle you want
Or you could borrow my bender, stop by

Chris

 

[sweetheat]

DC, we used 1 1/4" square fin tubes in parallel on the ceiling of our shop. About 2 feet apart. The 1st fin tube is lowest rising to the next and all rising up to the last then back. Effective. Sweetheat :lol:

 

[tuolumne]

I'm just guessing here since fluid dynamics and thermodynamics were a long time ago. It seems that you either do a manifold at top and bottom with fin tube in parallel, or run the fin tube horizontally (like a leach field) if you want to do series in order to keep a thermosyphon going. You can make any compound angle with pipe fittings if you fiddle for a minute. I'm sure that a 45 and a street 45 will do what you want to go from vertical to a 4 pitch roof.

 

[WoodNotOil]

Something interesting came up in an Eko overheat thread a few days ago that might give Tarm owners an alternative. Eko apparently sells an overheat device that resembles a domestic coil that runs tap water through a coil in the boiler when the electricity goes out. My thought was that Tarm owners with a DHW coil in their boilers could put a normally open zone valve on their DHW coil and have it open when electricity goes out pulling water through the coil to cool the boiler. You of course would need to have the water exit your boiler room somehow. Two questions I have about it though are:

1. Would constant water going through the coil lower the temp enough in a real overheat situation? (ie 10% or whatever of the boiler output)

2. In extended power outages that is a lot of water to waste and the boiler might not even be overheating. How does the Eko system handle that?

Just curious, as it would seem to be less expensive to setup for those with DHW coils already.

 

[DenaliChuck]

WoodNotOil - good idea for those on city water...our well pump and pressure tank have no electricity when the power goes out so it wouldn't work for us. But for others it could be a great heat dump.

tuolumne - do you think either series or parallel would have better flow?

olpotosi - good idea to supply the water in copper pipe to the TOP of the fin tube and let the cooling water in the fin tube help continue the flow down.

Sweetheat - are you tubes plumbed in parallel or series (so the water passes through all fin tubes on its path back to the boiler)?

Thanks for the fitting advice for making the turn. I also thought about filling some copper pipe with sand and using a conduit bender to make the bend too. Two 45* sounds like a good way to go with minimal turns to slow the water down.

Thanks everyone!

 

[sweetheat]

DC: all are in series (all connected together) but also parallel to each other and horizontally mounted under the 2nd floor. sweetheat

 

[DenaliChuck]

DC: all are in series (all connected together) but also parallel to each other and horizontally mounted under the 2nd floor. sweetheat

Got it. Thanks!