Advice on thermal storage tank (1040 gallon)

[DSSA]

I’ve procured a 1040 gallon tank to use for thermal storage.

I have it unloaded from the trailer in the garage it will live in, but before getting it upright and moving it, I wanted to see if anyone has advice that I should know/consider with insulation/mounting.

I had planned on spray-foaming the bottom of the tank before standing it upright, but also didn’t know if it was really a requirement or highly suggested to place something between the skirt of the tank and the concrete floor as well.

I’m just trying to have everything planned/thought out before getting it upright and into position—she’s a bit heavy/ungainly (2400lbs.) so I’d like to only do it once.


Thanks for any advice/suggestions on mounting/insulation/anything else I’m not thinking of!

 

[DSSA]

Additional notes/information:

The tank will be housed in an insulated garage which gets to freezing temps. We've had colder nights here lately 15-18 degrees, and the garage, without being heated typically stays above 35 degrees minimum. I'm not too worried about it freezing while not being used, noting the above and it being 1000+ gallons, but would like to string out batch burning as much that can be reasonable, and don't want to cook myself out in the summer when we use it to heat DHW. I've looked at several options, but am unsure what R value I should be shooting for.

If I wasn't trying to conserve space, I'd just build walls around it and insulate it with foam boards/fiberglass/etc., but she's a big girl as it is, and I'm already losing a lot of space in that building for this system. I'm trying to find the best ROI tipping-point here.

 

[PassionForFire&Water]

We use this type of tanks a lot.
We spray foam them with a minimum of 2" of closed cell foam.

We do not put a thermal break between tank and concrete floor.
It is a good idea tough.
Maybe a high-density plastic sheet.

I recommend you use a 2-port piping setup, instead of a 4 port.
Less disturbance of the thermal stratification
It looks like you have at least one 6" port.
Can't see the other ports

 

[DSSA]

We use this type of tanks a lot.
We spray foam them with a minimum of 2" of closed cell foam.

We do not put a thermal break between tank and concrete floor.
It is a good idea tough.
Maybe a high-density plastic sheet.

I recommend you use a 2-port piping setup, instead of a 4 port.
Less disturbance of the thermal stratification
It looks like you have at least one 6" port.
Can't see the other ports

View attachment 344061

Two ports on opposing sides (one high, one low).

I had planned on doing just 2-ports as pictured.

Thanks for the insulation and thermal break info!

Much appreciated!

 

[OffGridICF]

Spray foam is a great option but I ended up using Rockwool batts and regular fiberglass insulation packed into an enclosure around the tanks (minimum R15). You will save some space with spray foam but probably not a lot. I have 4 tanks in series with angle iron legs hooked up in a 2-port configuration. The legs have a flat base plate which sits on a layer of 1/2" OSB and 1" 25PSI EPS foam. I'll include a thermal image showing the temperature gradient from the tank to the concrete floor. With one large tank like yours I'm not sure if 25PSI foam would be adequate. Probably OK with a thicker layer of OSB or some LVLs laid flat to spread the load.

In a 35F garage the heat loss will be significant without good insulation. You might consider spray foam plus 3" of additional insulation, otherwise you may be unintentionally heating your garage. The hottest water will be at the top so adding more insulation there will be good.

If the system is not running, how will you make sure the rest of the plumbing around the tanks does not ever freeze?

 

[DSSA]

Spray foam is a great option but I ended up using Rockwool batts and regular fiberglass insulation packed into an enclosure around the tanks (minimum R15). You will save some space with spray foam but probably not a lot. I have 4 tanks in series with angle iron legs hooked up in a 2-port configuration. The legs have a flat base plate which sits on a layer of 1/2" OSB and 1" 25PSI EPS foam. I'll include a thermal image showing the temperature gradient from the tank to the concrete floor. With one large tank like yours I'm not sure if 25PSI foam would be adequate. Probably OK with a thicker layer of OSB or some LVLs laid flat to spread the load.

View attachment 344071
In a 35F garage the heat loss will be significant without good insulation. You might consider spray foam plus 3" of additional insulation, otherwise you may be unintentionally heating your garage. The hottest water will be at the top so adding more insulation there will be good.

If the system is not running, how will you make sure the rest of the plumbing around the tanks does not ever freeze?

I'm starting to look at spray-foaming the bottom and top, then have been looking at 1/4" Aluminum/PE thermal barrier to wrap it in.

As for freezing, it's not a concern. The system will be tied into the oil boiler in the house, which I can circulate in worst case scenario, and the garage it's housed in has an oil fired furnace that I can run to keep it from freezing if the need arises.

I appreciate your data input, and response. Thank you!

 

[DSSA]

I just received an order of '

Kraken Bond Fastcoat Fire Rated Spray Foam Insulation Kit Closed Cell​

' today. It's supposedly 5.66 R-value per inch.

I planned on cleaning the bottom of the tank (including wiping it down with a solvent to remove any grease), then heating the tank with a weed torch until I see a 90-100 degree reading on the tank metal before spraying a 3" coating on the bottom. I'll heat the garage to around 70 degrees, and will have the foam cans in the furnace room of the house to heat them to around 75-80 degrees.

Just looking for any pointers I may not be aware of before doing this and getting it upright (and off of my damn car lift!).

I understand that the bottom of the tank will be the lowest heat loss area due to stratification, but I'm okay with 'overkill', so long as it's not a blatant waste of money.

I tore off the drain piping and resealed all of the joints already, as I don't want to risk a leak once it's upright and insulated.

Thanks, and Happy New Year to all!

 

[OffGridICF]

Do the instructions say anything about spraying multiple layers instead of trying to get to 3" all in one pass? I've heard of curing issues and heat issues with too thick of an application in one pass.

I used a DIY spray foam kit (two cans mixed in the gun) inside on the roof of a shipping container to prevent condensation. It was going great until an afternoon thunderstorm with some sleet rolled through. The rapid temperature change caused the foam to pop off the ceiling in a giant slab. Fortunately only about 50 square feet had been done. After it warmed back up I redid that area and the rest. That was over 5 years ago and it's held up well.

The stuff sticks especially well everywhere you don't want it! Making a spray booth out of thin plastic sheeting and covering the floor is a good idea. Wearing a Tyvek suit with a hood, goggles, respirator, old clothes and old shoes is also a good idea since it will float in the air and coat everything.

 

[DSSA]

Do the instructions say anything about spraying multiple layers instead of trying to get to 3" all in one pass? I've heard of curing issues and heat issues with too thick of an application in one pass.

I used a DIY spray foam kit (two cans mixed in the gun) inside on the roof of a shipping container to prevent condensation. It was going great until an afternoon thunderstorm with some sleet rolled through. The rapid temperature change caused the foam to pop off the ceiling in a giant slab. Fortunately only about 50 square feet had been done. After it warmed back up I redid that area and the rest. That was over 5 years ago and it's held up well.

The stuff sticks especially well everywhere you don't want it! Making a spray booth out of thin plastic sheeting and covering the floor is a good idea. Wearing a Tyvek suit with a hood, goggles, respirator, old clothes and old shoes is also a good idea since it will float in the air and coat everything.

It went well, I put some plastic and cardboard under the tank while I sprayed, and just wore old clothes and an N95 mask.

The cans cover WAY less than expected, but I have a 3"+ coating on the inside (roughly R-17+) and am fighting adding another layer to bring it above R-20 (overkill-ish, for the bottom of the tank), and it took 5 cans (at about $20/can, so roughly $100). I brought the garage temp up to 70 degrees with the oil furnace, and heated the tank with a roofing torch, up to 60+ degrees and then let it stabilize for about 30 minutes before the first coat. I also misted it with water between coats.

Overall, it went decently, now I'm figuring out how to get the tank upright before the possible 2' of snow we're getting on Sunday, and looking at how hard I'm going to have to grab my ankles to insulate the rest of the tank, and buy the 11", 8-bolt flanges I need to take care of the inlet and outlets to attach piping. :-(