Simpler Heat storage setup???

Ok, I've been around here since 2007. I've owned a outdoor wood boiler for 10 years and ever since I've read about adding heat storage I've been fascinated by it. The only problem is everytime I start reading about it and how to set it up I just get confused on how to set it up. My current set up is a primary/secondary piping and works great. My outdoor wood burner is a unsheltered type and is 40ft from my house in a 8'x12' shed. My primary loop goes from my shed to my house and over to my shop and back to the shed. I have a Taco 011 pump on my primary loop that runs all the time. In the house I have a side arm heater on the primary loop heating my electric water heater. It then runs over by my forced air LP furnace where I have 2 tees 6 inches apart with a Taco 007 pump on one tee controlled by a thermostat and a heat exchanger in the plentum. I have the same setup in my shop but don't use it much in my shop. This was all designed by a guy that designs heating and cooling systems for a living. My house is 1100 square feet and my unfinished basement is 28'x28'. I've come to the conclusion that I would need at least 500 gallons of storage to make it worth while. My boiler is a pressurized system and I'm thinking of making a wooden heat storage tank with the proper liner that is unpressurized. I've seen many storage tanks built this way and looks like the easiest setup to build. There is no way I can get a 500 gallon propane tank in my basement. Plus if in the future when I'm older or whatever and I decide not to have the boiler setup anymore it would be easier to remove it.
So after all this babbling about my current setup now comes the question. What would be the simplest way to plumb a wooden rubber lined heat storage tank into my system? I seem to think if I build a copper piped heat exchanger and install it in the unpressurized tank then just plumb it into my primary circuit. Why wouldn't it work? I really want to batch burn has I can see all kinds of positive things about it. Like I said, I understand heat storage and how it works and I can see the advantages of it, but I just can't figure a good, simple, and cheap way to plumb it into my system.

I've studied that diagram in the past. I understand the plumbing part where I get lost is in the controls. You mention "solar water heater control"? Do you have a reference to the part your using? Can you give me a brief run down of how your controls work?

NateB said:

https://www.supplyhouse.com/Honeywe...5-200F-range-5-30F-Adj-Differential-1738000-p

This is the aquastat is powered when a thermostat calls for heat via a relay. (above 140 turn on the tank circ, below 140 turn on the oil boiler circ)

https://www.supplyhouse.com/Tekmar-156-Difference-Setpoint-Control-On-Off-7954000-p

I use this control to put heat into the tank. It has 2 temp probes one for the tank, one for the primary loop after all the loads, but before the tank. If the water is 20 deg warmer the tank circ turns on.

Relays
https://www.supplyhouse.com/Functio...Amp-SPST-Override-w-10-30-VAC-DC-120-VAC-Coil

I used 4 for 2 zones. One to feed the aqua stat, and one to turn on the zone circ.

Hope this helps

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Thank you, yes this helps a bunch!

Karl_northwind said:

Hi,
Sometimes with an OWB storage is worth it, sometimes it's not. It really depends on the type of boiler, what sort of efficiency it burns at and how well it shuts down. If the boiler is crap efficiency and only runs at 40% if it's running well, don't bother. that is a function of boiler design, wood selection, and air control.

if on the other hand it's capable of running at 65-70% when tuned and running well, storage might gain you something. pressurized storage is a pain, unpressurized storage is a pain.

what sort of boiler is it? if it's outdoor and pressurized in this neighborhood I'm going to guess that it's an aquatherm. they all seem to be pretty bad combustion wise, and serious forest eaters, in which case adding storage probably won't get you much. the reason everyone here on hearth loves storage (and rightly so) is they are mostly burning low-mass gasifiers, which aren't designed to run without storage (mostly) and will run 80-90% efficiency when doing it right.

If you smell a lot of "mostly" coming off my post, it's because the exception always is going to prove the rule here, as soon as I make a claim, someone will be doing it differently.

There is a whole lot of "your-mileage-may-vary" in this solid fuel combustion world.

cheers.
karl

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Yes I do have an Aquatherm. The reason I'm wanting storage is so I'm not tied to this boiler. I've operated this thing for 10 seasons now and have a pretty good handle on how to run it. My first season I used close to 10 full cords. I now use 5-6 full cords. This reduction in wood has come from learning the boiler and knowing how much wood to feed it. I also learned the first year that seasoned wood is the only kind of wood to burn. That being said, I'm not expecting any effiencey gains by adding storage but just convience in operating it and not feeling tied to it all winter. Take this week for example. Monday mourning got up to outdoor temperature of -1F. Tomorrow (Wednesday) is forecasted to be 42F. With temperature swings like this I'd be able to skip a day of adding wood or having a fire. Plus when it gets above 32F my stove idles too much and likes to get bad creosote build up.I know I can adjust the differential on my aquastat, but don't care too. I know my boiler will never be has efficient has a gasifier, but a little more convient would be nice.