New NP Storage Tank

[mtnmizer]

Heres a pic of my version of a storage tank.. Many
thanks to everyone on this forum for all the information
shared that was put into this project. I hope to get
it all hooked up soon and ready for winter.

Details on the tank are 420gal 5'x6'x2' 10 ga mild steel, folded corners,
externally reinforced via 2" angle in the middle,bottom and top,
lapped and double welded on the end seams. 3 piece bolt down top,
3 3/4 taps for vent, drain ect. Maybe 500lbs I can lift one end, took over
a hour to unload from pickup and move into daylight basement

Stainless Steel might have been better but @ 3x cost,
this should outlive me. I asked if it had been leak tested,
and was told "Jeff welded it". Need I say more

Can anyone suggest the best insulation option
bottom coating/paint and
anti corrosion additive in water.

Would 100' of 3/4 copper be enough for 150k
boiler split into 2 coils?

Comments, suggestions appreciated

MM

 

[sdrobertson]

As for the insulation - I went with building a box to enclose the tanks and then filling the box with blown in celulose insulation. High insulation value, will take the heat, and is treated with rodent repellent. My tanks are propane tanks standing on end with a rim welded for a stand. I used 12 to 14 inches of styrofonam beads (block wall filler) for the bottom in case I ever get moisture in the box as the beads will shed the moisture and the bottom 4 inches of the tanks should never get above 180 degrees.

 

[stee6043]

The photo almost looks like you're putting your tank on plywood sub-flooring??? Is it not in the basement? That hoss will be heavy....I hope you have concrete under it and not just floor joists?

 

[mtnmizer]

The photo almost looks like you're putting your tank on plywood sub-flooring??? Is it not in the basement? That hoss will be heavy....I hope you have concrete under it and not just floor joists?

It's on a 4.5" concrete slab with radiant piping & 2" of blueboard insulation . The weight calculations
total @ over 2K and at 300+lbs sq ft. Might have to fab a strap or two over to a stud. The
red stuff is redgard antifracture membrane for tileing..

I'm thinking a foam board insulation held in place with banding, I'm not aware of
any adhesive that's rated at 200 degrees. 1" of iso under 2" of blueboard?

Anyone know if the water additives at woodboiler solutions have an unpleasant smell?

MM

 

[deerefanatic]

Yes, they do..... I used their Preclean-776 and it smelled.... I didn't use the anti-corrosive additive though.....

 

[Nofossil]

Why split your heat exchanger coil into two? A single bi-directional coil gives you twice the performance for both charging and discharging. A 100' coil is a bit small, but a 50' coil wouldn't even be close for the transfer rate you're talking about, especially as the tank gets hot.

 

[mtnmizer]

Why split your heat exchanger coil into two? A single bi-directional coil gives you twice the performance for both charging and discharging. A 100' coil is a bit small, but a 50' coil wouldn't even be close for the transfer rate you're talking about, especially as the tank gets hot.

Thanks for some input here.

I'm thinking 1.25" as a the output size on the boiler which would need
two .75" coils in the tank in order to flow a 10gpm pump.
Boiler is a Econoburn 150K-- each 10k btu needs 1 gpm or am I
too under sized in my calcs? Or a pair of 100ft .75" coils off of a
1.25 line? Copper is dropping in price at the scrap yards should
work through at the supply end in time..or maybe do a flatplate
HX. MM

 

[Nofossil]

Why split your heat exchanger coil into two? A single bi-directional coil gives you twice the performance for both charging and discharging. A 100' coil is a bit small, but a 50' coil wouldn't even be close for the transfer rate you're talking about, especially as the tank gets hot.

Thanks for some input here.

I'm thinking 1.25" as a the output size on the boiler which would need
two .75" coils in the tank in order to flow a 10gpm pump.
Boiler is a Econoburn 150K-- each 10k btu needs 1 gpm or am I
too under sized in my calcs? Or a pair of 100ft .75" coils off of a
1.25 line? Copper is dropping in price at the scrap yards should
work through at the supply end in time..or maybe do a flatplate
HX. MM

The 1 gpm per 10k BTU is based on a 20 degree drop / rise. It's a good rule of thumb for boiler circs and for heating zones, but it's simplistic for storage - especially if there's a heat exchanger involved. Here's the problem: boilers and heat zones have pretty constant temperatures, but storage does not. When you first start heating a cold tank you're looking at a temperature drop somewhere near 80 degrees - doesn't take much of a flow rate to transfer 150K BTU under those conditions. As the tank gets hot, you'd like to operate with a temperature drop of less than ten degrees. That's very hard to do at any flow rate. You probably need to resign yourself to transferring a lot less than 150,000 BTU per hour as the tank gets closer to peak temperature. By the way - most boilers don't operate continuously at their peak rating. My EKO is rated at 80,000 BTU, and it can put out a bit more than that. However, a more realistic average over the course of a fire is 60k or 65k.

I don't have the calculations here, but I think you can flow 10gpm through 3/4" pipe with no problems.

 

[mtnmizer]

Thanks NoFossil, looks like I give a 100' of 3/4
a try and add more later.. MM