New guy DIY heat storage and MB55 Solo plumbing

[nhtreehouse]

so with the propane tanks i don't have to worry about rust since they are much thicker?

Yes. My 1000 gallon tank is 5/16" thick on the cylinder and 1/4" thick on the heads. It should weigh in at around 1800 lbs. In comparison, oil tanks are measured in gauge, not inches. I'm sure someone here knows how thick they are, but a guess would be 14 gauge. That's a bit over 1/16". Pressure is no problem with propane tanks as they are originally built for something like 250 PSI. Another important fact is that with a propane tank you can run the system pressurized without a heat exchanger, as others have commented on here.

Other members have cut propane tanks down and used multiple tanks for tight locations. It works.

I put together a simple spreadsheet to calculate tank volume. Using that tool, I come up with about 277 gallons per tank if you start with a 500 gallon tank which is typically 37" in diameter, and cut it down to 6' length overall. That assumes the heads/ends are hemispheres which is not always the case. Your mileage may vary here. Happy to share the spreadsheet - just PM me.

 

[maple1]

so with the propane tanks i don't have to worry about rust since they are much thicker?

Well, partly. Most of the rust worry goes away by having things pressurized - no fresh air in the water to make rust. And LP tanks allow for pressurized. But if you are cutting & welding them, you want to be very careful how you do it. They are designed the way they are for the pressure, so changing that by reconfiguring the tank itself can change their pressure handling capabilities. That plus making sure the new welds themsleves can stand the pressure without leaking. I had bungs welded on mine by a pro shop and even they had to touch them up in spots due to pinholes in the welds. Partly my fault for accidentally getting cast fittings.

 

[peakbagger]

Your question raises a red flag. There are two types of storage, pressurized and unpressurized. With pressurized you heat up a tank of water through a heat exchanger and then you need a heat exchanger (maybe the same one) to get the heat back into the radiators. Its decidedly more complicated.The reason you need the heat exchangers is that most wood, gas and oil heaters are cast iron with iron pipes. If you just circulated the water in the boiler to the tank without a heat exchanger, oxygen would get into the boiler water and rot the boiler out quickly. A pressurized system uses a closed tank that can be operated at the boiler pressure with no need to vent oxygen into the system. Its simpler to hook up but the trade off is you ned a tank capable of being pressurized with the right connections. A propane tank when built did have the pressure rating but not the right connections. This means that you need to have the right connections welded onto the tank. Unless the welder and his company has a special certification, the tank loses its official pressure rating. The typical reason the tank is available to begin with is its age or condition means that the original owner did not want to re-certify it or it was not able to be re-certified.

Some states like Mass technically require that any pressurized tank installed have a valid certification, many do not. The risk for a tank full of water failing is very low compared to one full of propane or air. Water cant be compressed so when the tank fails it most likely leaks all over the floor. When a tank full of propane or air fails it can explode and throw shrapnel around. Therefore many folks who heat with wood and use a modified propane tank accept the risk from a leak and go pressurized.

At this point I would suggest you do a lot of research before buying anything. Plenty of folks are willing to help you decide but ultimately if you are DIYing it you need to understand the basics or you will get into trouble.

 

[sardo_67]

yes i am doing a pressurized system, much simpler, easier and cheaper than building the heat exchanger and what not.

i have been a production welder for a few years before my current job and will be pressure testing these before i install them, it's just hot water, not working on 4,000PSI natural gas transfer lines here, ill put about 50psi into the tank then check all the welds with some soapy water for bubbles.

my issue is i have an MB55 which is 140,000BTU for my house and garage that only add up to about 1500sq feet of living space so i really need storage or the boiler will be choked down very low and clog up pretty quick. then add in the horrible efficiency which won't help either.

i've been reading a lot on here over the past year+ and learned a lot, just things didn't work out last year as i took on too many things at once, now i am in a much better situation both time and finance wise to finally finish this project.

 

[sardo_67]

ok one thing i forgot to ask about is how to insulate these?

build a box around them?

spray foam?

blankets of some kind?

 

[maple1]

I did a simple box.

 

[sardo_67]

going to start cutting and welding on my tanks, however i am not 100% sure how i am going to route the water flow and plumbing.

simply put should i go with option 1 or two?
i know there is a lot more in the system however i just made it extra simplified for conversation sake

 

[salecker]

going to start cutting and welding on my tanks, however i am not 100% sure how i am going to route the water flow and plumbing.

simply put should i go with option 1 or two?
i know there is a lot more in the system however i just made it extra simplified for conversation sake

Neither.
My system was designed by the guy i bought the boiler from,he is supposed to be one of the best in the Territory of 40000 people.
My sytem feeds into the top of tank 1 with 11/2 pipe with a reducing tee to the top of tank 2 with 11/4.
Then the return comes out of the bottom of tank 1 with 11/4 and upsizing to 11/2 at the tee from tank 2 which is 11/2.This a reverse of the input plumbing. My tanks balance equal both charging and discharging.

 

[sardo_67]

Neither.
My system was designed by the guy i bought the boiler from,he is supposed to be one of the best in the Territory of 40000 people.
My sytem feeds into the top of tank 1 with 11/2 pipe with a reducing tee to the top of tank 2 with 11/4.
Then the return comes out of the bottom of tank 1 with 11/4 and upsizing to 11/2 at the tee from tank 2 which is 11/2.This a reverse of the input plumbing. My tanks balance equal both charging and discharging.

ok so how are they organized though, one feeds into the other or both equal?

i am going to use the HS tarm print here as my basic guide but i am not 100% sure about all of it. like as you mentioned what size to use for the pipes and fittings or where to place them on the tanks.

(see wood plumbing example #4)

 

[salecker]

ok so how are they organized though, one feeds into the other or both equal?

i am going to use the HS tarm print here as my basic guide but i am not 100% sure about all of it. like as you mentioned what size to use for the pipes and fittings or where to place them on the tanks.

(see wood plumbing example #4)

They both feed equal in the top and return in the bottom.They are standing. the flows to top is reversed from the flows from bottom bottom.
top feed from boiler is 11/2" pipe then a reducing tee with 11/2" feed going into tank 1 and 11/4" into tank 2
return feed to boiler is 11/2" pipe as well,comes out of tank 1 with 11/4" then into a a tee which picks up tank 2 with 11/2"pipe.
The reversing of which tank is first in line is what helps the tanks charge even.
I was told to build a double check valve into the return line as well,not sure what it does.Sometimes i look at it and think that it may have been a joke on me,seeing i didn't know anything about hydronic heating when i built the system.

 

[maple1]

AKA 'reverse return'.

 

[sardo_67]

Salecker1 do you have your diagram still?


Also since my tank is open should I put any baffles or anything inside it?

 

[salecker]

Salecker1 do you have your diagram still?


Also since my tank is open should I put any baffles or anything inside it?

My diagram was in my head.
We layed out all the fittings in the shop where i bought everything.Started at the boiler hot side and built it on the floor till everything was accounted for.Then he put everything in 2 box's,one copper and one threaded black iron.
I got home and emptied out the box's of fittings and though what did i get my self into. Remember that i had zero experience with hydronic heating.But i ended up doing the same thing on the boiler room floor built the system with fittings,then all i had to do was measure pipe,clean,grab a fitting clean and solder,or prep the threads for hemp and install.
And no you don't need any baffles.Make sure you have enough ports for what you want.I have 3 wells in my tanks for temps,i only used 2 so far top and bottom.Inlet at top outlet on bottom.I kind of wish i had put a big port near the bottom for a big electric heating element,just in case i have electricity to burn from a solar installation,but i would rather sell it to the grid if that happens,wood is free.

 

[sardo_67]

how many bungs should i weld into my tanks and where do i need them located?

90* straight in on the cylander part or up higher/lower on the cap part?

 

[maple1]

Generally speaking- as few as possible and as high and low as they will go.

 

[warno]

You can put your ports anywhere you want but like maple said generally as high and as low as possible. I put my supply header about center of the head on my top tank. Keep in mind my tanks are horizontal. Only reason I centered it was because I use a portion of my top tank as expansion as well.

Don't be scared to put the ports directly into the heads, that's the strongest part of the tank anyway.

 

[sardo_67]

ok that is what i was thinking but i wanted to make sure, as for the bottom one i'll probably put that one up a i little so any sediment that collects on the bottom of the tanks won't get sucked thru the system.

if work lets up this weekend i plan on welding at least one of the up

 

[sardo_67]

Cut and welded both back up, doing a leak test and re-welding a few sections with pin holes.


Will be talking with Chris at Tarm Monday to go over a system and buy all the needed parts.

 

[sardo_67]

1-1/2" bungs welded in top and bottom, used some pieces i had laying around as a jig to make sure i welded them in and won't have any alignment issues.

for the bottom feed i will be using a 45* street elbow into a 1-1/2" 90* with 3/4 bung for the boiler drain so i'll be able to empty them if i ever need to in the future, last pic shows a mock up of what i will have as i was playing around with possible combo ideas. according to Chris at HS Tarm in NH i will have 1-1/2" connecting the tanks then T off in the center to 1-1/4" pipe for the rest of the system to wood/oil boilers and the house zones.


later this week i will be getting my friend L48 to pick up and lower them into my basement where i can start plumbing once the Tarm plumbing parts and controls get here.

 

[warno]

Looks like it's coming together. You plan on running that this year?

 

[sardo_67]

haha yea, i mean it better be up and running in a week or so, i'm already burning oil that i don't want to pay for

 

[salecker]

Do you have any temperature wells to monitor your water temps in your storage?
And are you doing a reverse loop to charge/draw from them?

 

[sardo_67]

Do you have any temperature wells to monitor your water temps in your storage?
And are you doing a reverse loop to charge/draw from them?

i was logging on here now to ask about that, i have 3/4" NPT bungs i will weld in at the top and bottom, for temp sensors, should i do pressure as well?

my idea was to put remote sensors in the tank then have a monitor i can see all 4 on since i will have these insulated and don't want to cut holes in them to see the gauges. will something like this work? if i run these type of gauges what is the simplest way to monitor them? https://www.amazon.com/dp/B079BP9HCJ/?tag=hearthamazon-20

other idea was to put wells into the bungs so i can change sensors out later if needed without making a mess, good idea or over thinking it? https://www.amazon.com/dp/B0087VJX9I/?tag=hearthamazon-20


i was on google and it sent me to amazon so i'm not set on any one mfgr or what ever, just the concept and preferaby not having to spend a few hundred, original idea was to get cheaper NAPA type analogue temp gauges for cars and run 4 of those.


i am going off of the Tarm example and how chris at Tarm said to plumb it, if you go up and look at post #34 the info is there

 

[maple1]

I wouldn't bother with wells or sensor bungs. More chance of leakage. I just used surface mount temp sensors, under my layer of FG insulation. If spray foaming I would still do that but stick a small tin can or something on the surface of the tank before spraying that the sensor can live in and still touch the tank surface. Or just spray & scrape a small area off after for the sensor to go on.

 

[sardo_67]

i'm just using foam sheets and 2x4s to frame up a simple box around them, nothing too crazy.

surface mounted sensors will work to show the temp difference?