Storage question

[Paso]

When you have a storage tank tee'd into the return line are you flowing the water thru the tank or just relying on thermo siphoning?

I know when you have two tanks side by side and they are teed together at the bottom both tanks maintain the same level of liquid.

I also know when using a side arm on the side of the water heater it will completly heat the water inside the water heater due to thermo siphoning.

So ........ when you have a storage tank right beside the boiler teed together at the bottom would the cold water be replaced or heated by the hot water in the boiler.

I would expect there would be a temperature difference between the two tanks but I am wondering if it would be significant temp difference.

The boiler tank water level would be higher than the tank by a few inches which would be equalized by a open pipe out the top possibly teed into the expansion tank on the boiler.

I'm thinking themo siphoning would heat the cold water to almost the boiler water temp.

What do you think????

 

[Paso]

Both would be open in this application. Boiler system now currently is an open system

I just thought that the heated water expands so it would, or possibly could, spill out of the top of the lower of the two tanks
( inches)

would the water heat is my main concern.

 

[Paso]

Does nobody have two tanks side by side teed at the bottom ?

I believe that the boiler water temperature would almost equalize simply by thermo siphoning Just as a side arm does.

Circulating the water would speed up the process.

I can't believe no one has any comments For or against I'll have to try it and report back.

 

[stee6043]

I think your question is a bit confusing. Most people heat open storage tanks with heat exchanger loops which receive hot water supply from the boiler. I've never heard of someone heating storage with gravity or thermosiphoning. I don't think you'd get particularly efficient heat exchange if you tried to run in this fashion. It may "work" but it also may take forever to heat your tanks. Also, how would you plan to retrieve the heat from your tanks???

 

[Nofossil]

Does nobody have two tanks side by side teed at the bottom ?

I believe that the boiler water temperature would almost equalize simply by thermo siphoning Just as a side arm does.

Circulating the water would speed up the process.

I can't believe no one has any comments For or against I'll have to try it and report back.

For thermosiphoning to work, you'd need connections top and bottom. In that case the tanks would equalize. IMHO, a much better approach would be to plumb them (and/or their heat exchangers) in series top-to-bottom to maximize stratification and get the greatest possible difference between the cold end and the hot end of your storage.

 

[Paso]

Sorry for the confusion

Yes I would be pulling water out the other side of the tank to feed a second oil fired boiler. Both boilers ( when operating )would be dumping water into the primary loop.

The OWB would be doing most of the work ( over capacity boiler at times)

I was hoping the thermo siphoning action would be getting the temperature up in the extra tank that the other boiler would be drawing from when it was needed, and at that point the water would be somewhat already heated.

We have extreme temperature swings and I was hoping to shorten the time the water came up to temperature by having storage .

 

[Nofossil]

Unless I'm missing something, storage will not help the system come up to temperature more quickly. Storage is typically used to absorb excess output to be used later when the wood boiler is not running.

 

[Paso]

I was thinking ( debatable that when the second boiler is needed it would be drawing from partially heated water.

Taking water from 50 F to 180 would take longer than taking water from 120 to 180 F

Is my thinking that far out of line??

 

[Nofossil]

I was thinking ( debatable that when the second boiler is needed it would be drawing from partially heated water.

Taking water from 50 F to 180 would take longer than taking water from 120 to 180 F

Is my thinking that far out of line??

If you don't have storage, then you don't have 50 degree water for more than a few minutes. The volume of water in the pipes is small and gets heated very quickly.

I do have to admit, though, that I circulate water from storage to flush cold water out of the zones when my controller detects that a wood fire has been started.