Heat Storage....Finally...!!!

[jpelizza]

After 6+ years of heating with my 150K Econoburn I'm finally getting storage bank! Can't wait till its all hooked and running.......been wanting this for LOOOOOOOONG TIME

I've been through lots of options on how to do it. I've settled on ordering 1100 gallon unpressurized 88"x88", 54" tall from americansolartechnics.com known on here as tom from Maine...

I'm putting it in my finished basement in a room that kicks out 12x16.

I'm just planning on running 1 1/4 pex from my heat bank to primary loop in utility room. I have radiant heat. I'm thinking of putting one circulator that will run automatically at 90 degrees or more. having two shut offs one for supply and one return by primary loop.

wondering how I get temp readings easily so I know what heat storage is an when I need another fire...

also any ideas how to tie into heat for pool as well.

tom helping get this all straight too but will take any ideas so I don't miss any thing...

thanks...

 

[peakbagger]

I have had a smaller AST tank for several years. One suggestion is to put dricore under the base insulation https://www.homedepot.com/p/DRIcore...core-Subfloor-Panel-CDGNUS750024024/202268752. This prevents any possibility of water pooling underneath the base. I put the base foam right on top of it.

Temp readings are easy. RTD type temperature readouts are cheap, you can mount RTDs in the foam making sure that its taped over before you put the liner in. Tom supplies a copper cap to put on top of the vent pipe. I put a slice in mine and have an aquatrol bulb hung down the vent pipe and also a type K thermocouple stuck down next to it. The only important temp you need is the top of the tank temp as the rest of the tank stratifies.

Tom warns you that the top of the tank can not be used for storage yet there is quite a bit of space above it. I built a set of wooden frames that are attached to the floor rafters above it and then have a removable deck that lays across the supports. I had to replace a liner at one point after it was in place and with the decking removed it didnt get in the way.

 

[warno]

To answer the temperature reading question, I went with some cheap temp display units from eBay. They were discussed here in a thread not that long ago. Here's the thread

Here's a pic of mine.

 

[jpelizza]

I have had a smaller AST tank for several years. One suggestion is to put dricore under the base insulation https://www.homedepot.com/p/DRIcore...core-Subfloor-Panel-CDGNUS750024024/202268752. This prevents any possibility of water pooling underneath the base. I put the base foam right on top of it.

Temp readings are easy. RTD type temperature readouts are cheap, you can mount RTDs in the foam making sure that its taped over before you put the liner in. Tom supplies a copper cap to put on top of the vent pipe. I put a slice in mine and have an aquatrol bulb hung down the vent pipe and also a type K thermocouple stuck down next to it. The only important temp you need is the top of the tank temp as the rest of the tank stratifies.

Tom warns you that the top of the tank can not be used for storage yet there is quite a bit of space above it. I built a set of wooden frames that are attached to the floor rafters above it and then have a removable deck that lays across the supports. I had to replace a liner at one point after it was in place and with the decking removed it didnt get in the way.

Tom did tell me to put 1" foam under heat bank when I asked him, I like what you sent me link on I'll do that, thanks!
looks like I can get a few temps by looking at what you did and that thread from other post here...

I do want one I can know what it is without going into my basement so either wireless if possible or maybe I can get a baby monitor with screen looking at a read out or something...

 

[jpelizza]

To answer the temperature reading question, I went with some cheap temp display units from eBay. They were discussed here in a thread not that long ago. Here's the thread

Here's a pic of mine.

View attachment 222344

thanks!, looks great!, I'll look at that thread...

 

[Marshy]

@jpelizza, I'm in the process of installing a new system in my house and have a 820 gal AST tank. I used the DryCore under my tank, then I put a base layer of 2" rigid foam board down and built the tank on it. If you want to see more of that install you can find it here...
https://hearth.com/talk/threads/froling-add-on-install.163423/

 

[BoiledOver]

Congrats on your storage install, you will enjoy it for sure.

Having more than one temp sensor in storage has benefits. I might have gone overboard but am happy to have all five inputs to determine the fire loads. The five are located at; the very bottom of the first tank (the zero gallon mark), midway up the first tank (the 250 gallon mark), on top of the first tank (500 gallon mark), midway up the second tank (750 gallon Mark), and on the top of the second tank (1,000 gallon mark). The tanks are 500 gallon propane units. This input allows for a very close account of how many btu's are stored and how many pounds of firewood is needed to get to a target amount of btu's in storage.

 

[peakbagger]

I had some spare thermocouples so I mounted them in the tank when I installed the liner. They just terminate with thermocouple plugs on the outside. I have looked at the numbers in the past but came to the conclusion with a single square tank its going to stratify and I am not going to be able to change that unless I circulate the liquid in the tank. Maybe it makes sense for multiple tanks but not really important with an single tank. I realize some folks like to over instrument these systems, but the best approach is KISS (keep it simple stupid).

 

[tom in maine]

One minor suggestion about what goes underneath one of our tanks.
Nothing wrong with something like Dricore, except if there is any dribbling from a fitting or condensation, over time, the OSB is going to fail.
Probably not a big issue, but if you want a drainage plane under the tank, use just the plastic part of the Dricore or get similar material, which is just the plastic (I cannot remember the product name!)

Sitting directly on Styrofoam is still going to allow any wetness to go around it onto a concrete floor.
Here at our shop, where we have a test tank that is not sealed, there are no issues sitting on foam on the floor.

No big deal either way, I am just apprehensive about anything that can decay due to wetness or the general humidity in the basement that cannot be easily dissipated.

 

[NateB]

This is what I used to get heat out of the tank and into the house.
https://www.supplyhouse.com/Honeywe...5-200F-range-5-30F-Adj-Differential-1738000-p

This is what I use to put heat into the tank. It has 2 sensors. I put one half way down the side of the tank, and the other sensor I put on the primary loop before the tank tees.
https://www.supplyhouse.com/Tekmar-156-Difference-Setpoint-Control-On-Off-7954000-p

I can give more details if you need.

I put the one inch of foam under my tank, and since it is in 2 pieces, I would see water coming out of the crack first if I had a leak.

 

[peakbagger]

Without going into details on the cause I got to see tank leaks in person twice on my installation and am glad I had a way of insuring that the air flow could dry the space under the tank.

 

[tom in maine]

To try to put this in perspective. If one of our tanks is wet on the bottom from a wet floor, a leak or condensation from another source,
the tank will dry itself once the issue is gone. A wet tank dries once heat is back in the tank.
Installing one of our tanks directly on a concrete floor is okay if the floor is dry. If it is damp or wet, there could be some corrosion on the framework.
1" of styrofoam on the floor, to segregate the tank frame from the concrete is prudent.
This being said, I have yet to see any failures due to the tank bearing directly on concrete.

With a layer of foam or a simple poly sheet under the tank protects the base in case some moisture finds it way to the bottom, the corrosion is not exacerbated by wet concrete in contact with metal.

The air space is not critical, but is not a bad idea, for any metal on damp surfaces.

 

[jpelizza]

This is what I used to get heat out of the tank and into the house.
https://www.supplyhouse.com/Honeywe...5-200F-range-5-30F-Adj-Differential-1738000-p

This is what I use to put heat into the tank. It has 2 sensors. I put one half way down the side of the tank, and the other sensor I put on the primary loop before the tank tees.
https://www.supplyhouse.com/Tekmar-156-Difference-Setpoint-Control-On-Off-7954000-p

I can give more details if you need.

I put the one inch of foam under my tank, and since it is in 2 pieces, I would see water coming out of the crack first if I had a leak.

thanks I'm checking all that out!

 

[jpelizza]

Ok trying to figure this out.

Have radiant heat so temps down to 90-100 during day heating , 115-125 nighttime heating..

Planning on running 1 1/4 pex from AST tank to primary loop in utility room...

I'm not sure on this part ... put a 90 degree circulator (its on anytime temp over 90 degrees) on the supply or return to tank near primary loop connection...???

Thought Is run boiler to charge up tank to 180..., turn boiler off, circulator runs heat from AST to primary loop as long as heat above 90 degrees...

Am I close...?

Also want to add another supply/return from primary loop to pool pump area to heat pool in may early June...

 

[jpelizza]

This is what I used to get heat out of the tank and into the house.
https://www.supplyhouse.com/Honeywe...5-200F-range-5-30F-Adj-Differential-1738000-p

This is what I use to put heat into the tank. It has 2 sensors. I put one half way down the side of the tank, and the other sensor I put on the primary loop before the tank tees.
https://www.supplyhouse.com/Tekmar-156-Difference-Setpoint-Control-On-Off-7954000-p

I can give more details if you need.

I put the one inch of foam under my tank, and since it is in 2 pieces, I would see water coming out of the crack first if I had a leak.

so does the acua stat then you set at what temp you want it to turn on circulator then??

 

[peakbagger]

I run my storage up to 185 F and then run the water from the heated water from the coil to the radiators when the zone thermostats call for heat until the temp out of the storage drops below 140 F. I have conventional baseboard so Its heating capacity drops quickly after that. Once the storage is below 140 F the tank coil is taken out of the loop. My oil boiler has a lockout relay on the burner so when the storage temp goes below 140, the oil burner turns on and the system becomes a regular run of the mill oil fired hydronic system that any burner tech can diagnose. If I turn the power off to the wood boiler, it also reverts back to an oil system. This complicates the controls a bit as I need to use relays and spring loaded valves to get everything to revert back to a regular oil system. A PLC would be easier but I dont use them as I have past experience with old PLCs and the loss of the ability to program them due to software compatibility.

 

[jpelizza]

I plan to turn propane back up off once I start to burn especially having heat bank..., so I just want simple... do they make circulator that will just pump to primary loop from heat bank above 90 degress...?


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[jpelizza]

This is what I used to get heat out of the tank and into the house.
https://www.supplyhouse.com/Honeywe...5-200F-range-5-30F-Adj-Differential-1738000-p

This is what I use to put heat into the tank. It has 2 sensors. I put one half way down the side of the tank, and the other sensor I put on the primary loop before the tank tees.
https://www.supplyhouse.com/Tekmar-156-Difference-Setpoint-Control-On-Off-7954000-p

I can give more details if you need.

I put the one inch of foam under my tank, and since it is in 2 pieces, I would see water coming out of the crack first if I had a leak.

Ok looks like that Tekmar I understand a little, I have a Tekmar that runs my radiant heat but looks like this one I hook into circulator that is on heat bank to primary loop, then I would just set it to run at 90+ degrees....right?


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[NateB]

Tekmar is little bit more complicated. It has a delta setting, a minimum setting, and a maximum setting. It compares the temperature of the primary loop with the temperature of the tank. You don't want to circulate 90 deg water into your 150 deg tank. The Tekmar is the scavenger of the system it takes the leftover heat and stores it, but if it is cooler it lets the water go back to the boiler to warm up. This part lets your boiler run full tilt until the wood is gone, and store the heat in the tank. It also has upper limit protection to keep from over heating your tank. Which is important because liners do have an upper limit. I think it is 185, but I never push the temp that high.

The aquastat is in charge of using the heat from the tank, or using heat from your propane boiler. There are 3 contacts on the aquastat one for power coming in, one to power if the temp is low, and one to power if the temp is high. The aquastat gets power from a relay that is turned on/off by the house thermostat. The aquastat only need to know the temp of the tank. Low turn on the propane circ, High turn on the tank circ.

Unrelated to the question, but I use a second relay to power the zone circ.

 

[TonyVideo]

I believe there is a sticky on this above the threads in this forum.

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[jpelizza]

Tekmar is little bit more complicated. It has a delta setting, a minimum setting, and a maximum setting. It compares the temperature of the primary loop with the temperature of the tank. You don't want to circulate 90 deg water into your 150 deg tank. The Tekmar is the scavenger of the system it takes the leftover heat and stores it, but if it is cooler it lets the water go back to the boiler to warm up. This part lets your boiler run full tilt until the wood is gone, and store the heat in the tank. It also has upper limit protection to keep from over heating your tank. Which is important because liners do have an upper limit. I think it is 185, but I never push the temp that high.

The aquastat is in charge of using the heat from the tank, or using heat from your propane boiler. There are 3 contacts on the aquastat one for power coming in, one to power if the temp is low, and one to power if the temp is high. The aquastat gets power from a relay that is turned on/off by the house thermostat. The aquastat only need to know the temp of the tank. Low turn on the propane circ, High turn on the tank circ.

Unrelated to the question, but I use a second relay to power the zone circ.

I was thinking I would circulate tank down to 90 degrees as my radiant heat will still heat daytime down to 90 degrees. so thats why I was thinking to have heat bank circulate all the time from 180 down to 90 degrees to primary loop...its night time that radiant calls for closer to 120 degrees...

 

[NateB]

I was thinking I would circulate tank down to 90 degrees as my radiant heat will still heat daytime down to 90 degrees. so thats why I was thinking to have heat bank circulate all the time from 180 down to 90 degrees to primary loop...its night time that radiant calls for closer to 120 degrees...

Yes you will set the aquastat to 90 degrees, so if the tank gets below 90 it will turn on the circ for the propane, or if it is above 90 it would turn on the circ for the tank.

Remember the aquastat gets power when the thermostat calls for heat.

 

[jpelizza]

Yes you will set the aquastat to 90 degrees, so if the tank gets below 90 it will turn on the circ for the propane, or if it is above 90 it would turn on the circ for the tank.

Remember the aquastat gets power when the thermostat calls for heat.

ok I think that sounds like a plan, i had an aqua stat for propane back up but it stopped working so I just turn propane boiler off now, when I start burning I just want to burn no back up...any ideas on size of circulator?

 

[NateB]

I use grundfos 15-58 fc for the boiler and the tank. I did not buy those based on any calculation. I bought those cause that is what fit in the budget.

 

[maple1]

They are very good circs. The 3 speeds can be very handy at times.