How to convert a 500g propane tank to a Storage tank

[Kristen]

I have two vertical tanks, because we could not "tip" a single tank due to ceiling height.

They are connected by a "snorkle" tube (purple arrow in photo below) from about 1/3rd down primary to top of secondary. In effect the pair of tanks stratify like a single vertical tank - heat gradient from top of primary to bottom of secondary.

In Summer we turn off the snorkle tube so that we only use the Primary. We only light the boiler occasionally, for the pool (which also has solar heating which is enough 85% of the summer), but we also have solar thermal on the primary store and that definitely cannot heat two tanks! but it keeps the top half of the Primary at 60C / 140F which is enough to heat the domestic hot water (we have a coil at the bottom of the primary to pre-heat the DHW and another at the top for final heat; the bottom coil will do all the work if the Primary is hot enough at the bottom, which prevents destratification, if that is not hot enough then the top coil does the remainder of the work).

 

[jebatty]

Vertical has certain advantages, but they are not overwhelming advantages.... Both vertical and horizontal will stratify effectively, especially if horizontal ports, internal riser and dip tubes, diffusers, or internal elbows are used to minimize vertical jetting.

I have a horizontal 1000 gal tank and ewd is exactly correct. Pictures will explain more fully. Boiler supply to top end of tank about 6" down from top with about an 18" pipe extension in the tank to direct hot supply water across the top of the tank. Boiler return is from the bottom of the tank at the same end, about 6" up from the bottom. System supply is from top of tank near the middle and system return is to bottom of tank near the middle via a diptube.

Personally, if I had the space, I would place a 1000 tank horizontally up on some sort of superstructure so I could use all the space below it. The boiler, plumbing, expansion tank, and a cord or so of wood could all fit below nicely.... You would likely prefer some other arrangement, but my point is that what matters is how best to make use of the space available in your own particular situation, not the question of horizontal vs. vertical..

True again, except that I boxed in my tank and fully use all the space above for storage. Much easier than trying to support a 1000 lb tank with 8,000+ lbs of water off the floor.

If you do go vertical, note that if you use horizontal ports from the sides of the tank, all the volume above the upper port and all the volume below the lower port will be lost for heat storage. To avoid this design defect you need to use an internal riser tube to inject or draw hot water from the top of the tank, and likewise you need to use an internal dip tube for the bottom of the tank.

This also can happen with a horizontal tank. My tank boiler return leaves about 6" of "dead" water below the return fitting, and this essentially does not heat when the tank is charged. The good news is that there isn't much water in this 6" of space, but also my system return at the middle of the tank via a diptube to the bottom does direct warm return water to the bottom of the tank and recovers some of this dead space volume.

Pictures: #1689 - tank in position in my shop
#1689 - welded fitting on the tank
#1695 - tank with boiler supply/return fittings
#1694 - tank with system supply/return fittings
#1705 - tank fully boxed in the raw
#1892 - tank finished boxing in, end with boiler
#1865 - tank finished end
#1815 - tank finished side view, with mural, storage above the tank

 

[Bj1234]

Thanks for all the pics everyone...pictures can tell someone so much... jebbatty- I might get back with you another time to pic your brain about your set up when i get to that point. Basically regarding the top of your tank. I thought in and out were all positioned on the sides but you have pipe and gauges on top of your tank to... is that because 1000gallon tanks are so long that you need to have some hot boiler water coming into the tank from the middle due to the leangth?

 

[maple1]

I don't know if you checked out my install thread or not, but here are a couple pics from it, of my tanks.

This one is after I got them home from the welder. The one on the right is rolled over a bit, the top tank inlet for incoming boiler supply (or outgoing load supply) is at the 2:00 position there, roughly. Bottom outlet to boiler return (or incoming load return) is at the bottom of the tank on the left. (Tank in foreground is for expansion).

This one is the other ends, after I got them painted & stacked and most preliminary fittings in, just before I rolled them inside. They aren't hooked together yet, I did that after I got them parked, but you can see the fittings for it in the middle.

 

[Bj1234]

Maple1..... I did see your threads, very nice.. does the bottom tank have the open inlets on top of the tank to, just like the top tank does?..

or does the bottom tank(on the sides) have 1 side in and 1 side out only..

 

[maple1]

Each tank has an outlet top and bottom, but on opposite ends. Then they're oriented so the top outlet of the bottom tank is on same end as the bottom outlet of top tank - per the last pic. Those get connected together (the 'run around' end, just connects the tanks) - basically makes them one tank. Fittings that would be on the other end of that last pic are top & bottom, that's where water enters & leaves the taks. Very simple.

There are also a couple of other small fittings (1/2 or 3/4, forget now) on each end top & bottom, for drain & vent purposes - can see the drains in the last pic. And I also have a couple of plugged holes on the centre top of the top tank that I could tap into in the future if I wanted.