Suggestions on storage tank piping, drawings now included

[goosegunner]

The other day I posted a question about Return to storage piping method.

https://www.hearth.com/talk/threads/78772/

I drew 3 different methods I am considering for piping

1. The Simple Pressurized storage Method

2. The Hydraulic Separator Method

3. Combination, Which is more pipe and a few more valves but I think it would allow me to use either style piping depending on the time of year or what I am heating.


Please provide any comments or suggestions on Which method you feel is best. I have also included the near boiler piping picture.

gg

 

[ewdudley]

The other day I posted a question about Return to storage piping method.

https://www.hearth.com/talk/threads/78772/

I drew 3 different methods I am considering for piping

1. The Simple Pressurized storage Method

2. The Hydraulic Separator Method

3. Combination, Which is more pipe and a few more valves but I think it would allow me to use either style piping depending on the time of year or what I am heating.

Please provide any comments or suggestions on Which method you feel is best. I have also included the near boiler piping picture.

'Simplest' and 'Separator' are pretty much the same, except 'Simplest' would supply hotter water somewhat sooner when starting a new burn after depletion of storage.

In diagram 1 connections to the tank could be on opposite ends as shown, or on the same end, no difference.

If storage tank mixing matters, which maybe it doesn't, it would be best to devise some way of getting the flows entering the tank to be horizontal, or maybe a nipple with its end sealed off, threaded into a double-tapped bush with a bunch of holes drilled in the sides.

 

[goosegunner]

My consideration for the Hydraulic separator method where I show using all for connection points is that it would be run as two independent systems. Charging on one end and Load on opposite. Also when I heat the pool in the summer it would temper the cooler return water before it hits the Danfoss allowing for more high temp water to reach the tank.

But maybe that is completely wrong way to think and would cause too much reduction in tank temp.

The tank ports are 2" I have 4 double tap 1-1/2" bushings. For the top ports I was going to put in 3 inch nipple with bottom capped and hole cut on side to help send water horizontally on the supply. I was going to leave the bottom ports straight out the bottom so I can drain completely when needed.

I thought the Simple Pressurized method was to be supply one end and return the other?

gg

 

[ewdudley]

My consideration for the Hydraulic separator method where I show using all for connection points is that it would be run as two independent systems. Charging on one end and Load on opposite. Also when I heat the pool in the summer it would temper the cooler return water before it hits the Danfoss allowing for more high temp water to reach the tank.

Both would function the same hydraulic-separator-wise. If excess flow from boiler some or none goes to load, the rest goes to the tank. If excess draw from load, some or none comes from the boiler, the rest comes from the tank.

The Danfoss does not care [much] if it has 90 degF or 128 degF at its 'C' port, it adjusts the proportion of flow coming in the 'H' and 'C' ports in order to deliver constant 140 degF (or whatever it's configured for) out the 'M' port.

I thought the Simple Pressurized method was to be supply one end and return the other?

It happens to be drawn that way in the sticky, but it means nothing.

 

[goosegunner]

Thanks for your input!

I could use the center ports for connections if that would help any thing.

I guess I have been making this thing more complicated than I need to. I should also be able to cut the costs down, especially if the Combination method is not needed, 1-1/2" copper is pretty expensive these days and I like the idea of using as many ball valves.


How about check valves, My circulators have the plastic checks, Do I need the weighted check valve in both Boiler supply and return?


gg

 

[ewdudley]

I could use the center ports for connections if that would help any thing.

Whatever is most convenient, I would think. The hot water will accumulate at the top of the tank and the cooler water at the bottom no matter what ports you choose.

I should also be able to cut the costs down, especially if the Combination method is not needed, 1-1/2" copper is pretty expensive these days and I like the idea of using as many ball valves.

From the photo it looks like the load lines are already teed to the boiler lines on the wall above and below the expansion tank shelf. I don't see why you need more that a single line over to the top and the bottom of the tank from there.

How about check valves, My circulators have the plastic checks, Do I need the weighted check valve in both Boiler supply and return?

I believe one thing you need to watch out for is that heated water can't reverse flow back though the boiler when the fire is out, where it could cool off and then flow to the bottom of storage continuously. The integrated flow check valve in the pump and the Danfoss should prevent that, but then again the Danfoss could open from H to C as low as 140 degF, so having another check valve might be better, although it looks like in the photo that it would need to be inserted between the Danfoss tee and the load tee left and above the expansion tank.

You already have the flow check in the pump to prevent forward flow when the boiler pump is off, not that you'd need it because hot water migrating to storage would normally be a good thing.

The other thing to prevent is parallel forward flow through the boiler when the load pump is drawing from storage and the boiler pump is off. The integrated flow check in the boiler circ should accomplish this and a weighted check would probably be overkill.

I guess I have been making this thing more complicated than I need to.

The complicated part is over on the load side where you may want to worry about storage mixing and backup boiler integration. If you have only radiant heating, the pool, and no DHW, then mixing might not be much of a concern.

 

[goosegunner]

Yes the boiler lines are T with the load lines. I did it that way so I could run it without storage.

So basically you are saying I only need to run the 1-1/2" boiler line to the tank. and leave the 1-1/4" lines dead end to the valve. When I run storage just open the 1-1/2" ball valves going to the tank.

I guess I thought the T lines had to be close to the storage, thats why I was going to put them right at the tank.


The check you speak of would be in the supply? (right between the T to Danfoss and the T between the supply and Load).


I have;

Winter
Forced air coil for winter heat that will heat down to 130 degree water. Aqua-stat kills pump if water is not 130 after time delay of 3 minutes
Eventually will add DHW.
May heat garage some when needed
Shed eventually occasionally

Summer
Pool heat
Maybe DHW

 

[goosegunner]

Updated drawing using T's already in the system.

gg

 

[ewdudley]

Yes the boiler lines are T with the load lines. I did it that way so I could run it without storage.

So basically you are saying I only need to run the 1-1/2" boiler line to the tank. and leave the 1-1/4" lines dead end to the valve. When I run storage just open the 1-1/2" ball valves going to the tank.

I guess I thought the T lines had to be close to the storage, thats why I was going to put them right at the tank.

It's normally drawn that way, and if it is physically that way then you're got a pretty good guarantee that the load pump will pull only from storage and will not draw any parallel flow through the wood boiler. But with your nice big pipes and with the boiler pump integrated flow check there should be no parallel flow through the boiler when the boiler pump is off and the load pump is running.

The check you speak of would be in the supply? (right between the T to Danfoss and the T between the supply and Load).

The more I think about it, my speculation about a need for that check valve would only come true in some fantasy condition. There would need to be flow from the H to C port on the Danfoss and than could only happen if the temperature was just so and the flow was just right to maintain the temperature just so. Ain't going to happen, and if it did, so what, pipe gets warm for a while. The check valve in the boiler pump will prevent reverse cooling flow through the boiler and that's all you really need to worry about.

I have;

Winter
Forced air coil for winter heat that will heat down to 130 degree water. Aqua-stat kills pump if water is not 130 after time delay of 3 minutes
Eventually will add DHW.
May heat garage some when needed
Shed eventually occasionally

Summer
Pool heat
Maybe DHW

With water to air HX maintaining storage stratification is pretty important. If the flow to the HX is too much then water goes round and round through storage and loses less heat than it should on each lap. As storage cools the HX fan runs longer and longer to maintain conditioned space temperature. With proper flow stratification the water is cooled as much as possible before returning to the tank and the amount of air per btu delivered remains constant through the storage depletion cycle.

But that problem doesn't affect what the storage piping you're doing now, so no need to worry about it for this phase of the project.

--ewd

 

[goosegunner]

Thanks for taking the time to respond with such detailed posts. Its funny how I studied these drawings for so long and with a some outside tips it really makes a lot more sense.


My problem is the computer, I get crazy ideas like this boiler, my pool and many other things. Many times I am dumb enough to do these projects myself and not smart enough not to try...

I did tell my wife after this Building, boiler project I should probably throw the computer out.


Thanks again for your help!

gg