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Sizing header

cabowen
cabowen Member Posts: 20
edited January 2019 in Radiant Heating
Hi-

I am plumbing two 500 gallon tanks for a gassification wood boiler storage. I have to use them horizontally and would like to plumb them in parallel with a two pipe system per Siegenthaler. Picture attached. I will have 1 1" supply to the tanks from the boiler and 2 1" feeds to my infloor distribution system. Will using closely spaced tees as below give me hydraulic separation ( 1 feed to each tank, 2 feeds to the floors, and one 1" inlet), like this:




Thanks...


Comments

  • Ironman
    Ironman Member Posts: 7,367
    I'm a little confused. You said you want to pipe them in parallel, but the drawing that you posted with yours has them in series. Also, in your drawing, what's gonna induce flow into and between the tanks?

    Are you asking for a correct drawing?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    GroundUp
  • cabowen
    cabowen Member Posts: 20
    edited January 2019
    Thanks for your reply. I only showed the supply header. There would be an identical return header at the other end of the tanks, putting them in parallel.

    When there is no heating demand, with the wood boiler firing, the hot water from the boiler is pumped into the tanks. When the tanks are fully charged and the boiler is not firing, water is pumped from the tanks to the zones as demanded.

    When the boiler is firing, and there is a heating demand, depending on the demand, supply from the boiler feeds the zones, with any additional required flow taken from the tanks. Similar to below:


  • GroundUp
    GroundUp Member Posts: 1,889
    Having the feed from the boiler and the draws from the tank in the same header like is drawn will not work, if that's your question. Loads need to come directly from the tank, typically 180 degrees from the boiler feed to the tank. Google "buffer tank" and study up a little, there is plenty of great info out there
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,452
    If you have 1" from the boiler I would feed each tank with 3/4" and I would put a balancing valve on the feed to each tank so you can balance the flow.

    As @GroundUp mentioned the zones should come off the tanks directly
  • cabowen
    cabowen Member Posts: 20
    edited January 2019
    GroundUp said:

    Having the feed from the boiler and the draws from the tank in the same header like is drawn will not work, if that's your question. Loads need to come directly from the tank, typically 180 degrees from the boiler feed to the tank. Google "buffer tank" and study up a little, there is plenty of great info out there

    The are not buffer tanks per se, but rather storage tanks...Please have a look at this:

    https://www.pmengineer.com/articles/92398-different-ways-to-pipe-a-thermal-storage-tank
  • cabowen
    cabowen Member Posts: 20

    If you have 1" from the boiler I would feed each tank with 3/4" and I would put a balancing valve on the feed to each tank so you can balance the flow.

    As @GroundUp mentioned the zones should come off the tanks directly

    If the two legs are identical I wouldn't need any balancing valves, right?

  • Ironman
    Ironman Member Posts: 7,367
    Are you attempting to accomplish thermal stratification? If so, it's not gonna be that much with a horizontal tank.

    If you're trying to accomplish tank loading with two tanks (as shown in Siggy's last drawing above), then I'd pipe from the wood boiler directly to the first tank (in series), then out of it to the second tank with everything else as shown in that drawing.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    Canucker
  • cabowen
    cabowen Member Posts: 20
    edited January 2019
    Yes, I am looking to get thermal stratification. Why not so much with horizontal tanks? I will have dip tubes which direct the flows inside the tanks along the horizontal axis....??? The results of this study seem to indicate I can expect stratification in my horizontal tanks:

    http://www.academia.edu/33514571/An_experimental_and_numerical_study_of_thermal_stratification_in_a_horizontal_cylindrical_solar_storage_tank

  • cabowen
    cabowen Member Posts: 20
    edited January 2019
    Looking into this a bit more, it seems the crucial details are to place the tees feeding the load as close to the tank as possible, and to use "generously sized" headers from the tee to the tank, as below. This gives hydraulic separation between the boiler supply circ to the tanks and the load circ to the load by keeping the head loss to their common piping as low as possible....

    Thanks for the replies...