DIY Pressurized Storage

[danmitchell9]

As a carpenter I think I'm going to need some help on this project. I've seen people use old propane tanks for storage, but I'm wondering about the "fitting/cutting into the tanks" aspect of the project. Any good links with up close pictures? Or does anyone recommend a good book?

 

[Nofossil]

Most folks do minimal cutting and welding. With pressurized, you don't need to put a HX coil inside, so most welding is just threaded fittings. Probably worth having a pro do it. It's not hypercritical - the tanks are rated for 300 psi, and hydronic systems max out at 30.

 

[Dave T]

If your thinking about DHW I have not seen it yet but I've heard of folks wrapping there propane tanks with coils of copper under the insulation for DHW, anybody have pics and results of this type of setup??If you have any doubt what so ever that your welds won't work have a pro do the tank welding I would not recamend learning on a pressure vessal..Dave

 

[tuolumne]

I had some trouble with welding fittings to a propane tank. Ulitimately, the mig I was using was underpowered. After borrowing a 220v stick welder I was able to achieve some leak proof fittings after several tries.

 

[djblech]

I would be very hesitant to cut or weld on an empty propane tank. There was a guy down the road that tried that about 20 yrs ago. The fire dept picked up the pieces after the tank blew up. He was killed instantly.

djblech
Greenwood 100

 

[DaveBP]

I would be very hesitant to cut or weld on an empty propane tank. There was a guy down the road that tried that about 20 yrs ago. The fire dept picked up the pieces after the tank blew up. He was killed instantly.

The safest way to prepare a propane tank for ANY work, even just moving it, is to completely fill it with water and then drain it. It will still smell like gas but the propane will be gone. The smell can linger for a long time and no, propane will not diffuse out of the "pores" of the steel and make it explosive again.

The dealer I bought mine from wouldn't let a tank off his lot without doing this and spray-painting WATER on both sides of them in large letters. I piped a small blower on mine and ran a gentle breeze through them for a couple months last summer. Hardly smell now.

 

[Huskurdu]

I am in the final stages of installing an 1.25" inlet tube into the far end of my heat storage unit (old propane tank), I've used it all winter for heat storage. It didn't work well because the inlet and outlet were right next to each other on one end of the tank, towards the top. We're welding a 1.25" black pipe on the other end that goes down to about 8" from the bottom of the tank. That should help diversify the heat I'd think. I'll try not to drop the pipe to the bottom of the tank the first time.
It's been full of water for several months so we're 'hoping' we live to tell the story. Shouldn't be a problem.

np

 

[hyattpeters]

Where are the best locations to place the inlets and outlets,and what about temp gauges and how many?? Whats the best way to place the tank(s) (horizontal or vertical) How big of black pipe should you use to plumb your tank(s)?? Do the copper coils wrapped around the tank work for DHW or is there some other way??

 

[Piker]

WHen charging the tanks... water goes in at top, out and back to boiler at bottom.

WHen discharging the tanks... water goes out from top, and back in to tank at the bottom.

You have to reverse the flow from charging to discharging. This can be done easily with Nofossil's simplest pressurized storage posted as a stickey at the top of the boiler room. I have researched pressurized storage extensively in the past months, talked to a few engineers, and this is the very best and simplest method I have seen.

The inlet and outlet size will be determined by how much flow is required.

Vertical will yield the best stratification... but horizontal will work fine.

I don't think wrapping copper around the tanks would be all that efficient... it seems like that would take an awful lot of copper to get enough heat transfer to do the job. I haven't tried this myself however... maybe someone has figured a way for it to work? I will be piping the DHW as it's own zone off the manifold. It's probably a little more expensive than how most folks do it though.

cheers

 

[2.beans]

I am in the final stages of installing an 1.25" inlet tube into the far end of my heat storage unit (old propane tank), I've used it all winter for heat storage. It didn't work well because the inlet and outlet were right next to each other on one end of the tank, towards the top. We're welding a 1.25" black pipe on the other end that goes down to about 8" from the bottom of the tank. That should help diversify the heat I'd think. I'll try not to drop the pipe to the bottom of the tank the first time.
It's been full of water for several months so we're 'hoping' we live to tell the story. Shouldn't be a problem.

np

screw a fitting on the end of the pipe that is going to be out of the tank then drop it in. the fitting will stop it from falling in.

 

[DenaliChuck]

I used a hole saw to cut 3.5" holes into my tanks...i filled them with water and then cut while full. Water is a good, cheap lube too.

I'm in the process of installing 80' of 3/4" copper laying on top of my hottest tank as a DHW preheat. I'll post if it works. I'm using this pattern:

__________________________
1_________________________
__________________________1
1_________________________

 

[mpilihp]

Would folks with pressurized storage mind saying what they have for connections on their tanks, where they are and what they are? IE Number on the top, what size they are, what they are used for and what type of connection (meaning is it a dip tube and is it wet or dry?)


State that for top, bottom and anywhere else?

THanks

Phil

 

[2.beans]

Would folks with pressurized storage mind saying what they have for connections on their tanks, where they are and what they are? IE Number on the top, what size they are, what they are used for and what type of connection (meaning is it a dip tube and is it wet or dry?)


State that for top, bottom and anywhere else?

THanks

Phil

i didnt use any of the factory locations for the pipes. on my first tanks i start from one end and equally divide the tank up for four new holes. then i lay them out supply from the wood boiler to the top return from the house to the bottom via dip tube, supply to the house to the top return to the wood boiler to the bottom via a dip tube. all pipe is black is 1" black iron. the dip tube are about 6" from the bottom of the tank. the tanks are placed in horizontally. the last two tanks i built i did them the same except the wood boiler supply i put in at the end of the tank at the top to try to help the tank from mixing.

 

[DenaliChuck]

2, 500 gallon tanks, plumbed in series, each with a 3" diptube to input to tank top and a 3" tube pulling from the tank bottom. Plumbed but not operational yet

 

[hyattpeters]

Can anyone post any pictures of their pressurized storage systems (2 500 gal. propane tanks in series) or links that have been posted in the past?? Just to help out with visual aspect. Maybe a dumb question but what is ment by a dip tube?? and what about cutting out and fabricating a flange in the side of the hottest tank to except a DHW coil out of a boiler for a prheat for the DHW Tank has any done this.(Like the type as in the attached pic.)

 

[mpilihp]

Hi Guys thanks, so what about temperure monitoring? Also do you have any aqustats to tell heat system if water is hot enough to heat from and how are those connected??

Phil

 

[WoodNotOil]

Hi Guys thanks, so what about temperure monitoring? Also do you have any aqustats to tell heat system if water is hot enough to heat from and how are those connected??

Phil

You could put wells in for temp monitors or threaded thermometers in threaded holes. Some of the existing fittings on the tank may be good for this. For digital temp these are nice and for analog there are these. As far as controlling the charge of the tank a differential controller works the best like the Tekmar 156.