Sizing header

cabowen

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...

Ironman

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?

cabowen

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

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

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

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

EBEBRATT-Ed said:

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

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.

cabowen

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

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...