Heat Storage, 1 large or many small tanks

[Blofeld69]

Hello
Hard to get a large tank where I am, I am wondering the advantages/disadvantages of having a large tank over having more smaller tanks connected together but same volume of water?
Many thanks

 

[ewdudley]

I went with three 250 gallon propane tanks.

They're short and skinny, so all three standing on end with insulation take up 4.5 ft wide x 9 ft long x 9 ft high, which makes a decent amount of storage, with a small, long and narrow footprint. With the room width available it worked out nicely, but of course most every situation will have its own optimum layout.

Disadvantages include more fittings, more complicated piping, and more complicated rigging and millwright work to get them situated. Also it takes a fair amount more insulation (per gallon) to do a good job of insulating simply because the storage is less compact with multiple tanks.

 

[stee6043]

As EW mentioned above the plumbing expense can really add up on when adding more and more tanks. Shut offs and the like are not cheap!

 

[arngnick]

One tank if you can find one that you can move into the space you have for it. One tank will give better stratification but many small tanks will work well if set-up correctly.

 

[Blofeld69]

I found a tank, about 5000 litre which is 1320 us gallons, what do you guys think? about 1000 us dollars. I thought this would be good as when not using it in the summer I could use it as a hot tub, tile it and deck the sides

 

[kopeck]

I found a tank, about 5000 litre which is 1320 us gallons, what do you guys think? about 1000 us dollars. I thought this would be good as when not using it in the summer I could use it as a hot tub, tile it and deck the sides

Is it Stainless steel? If it isn't you are going to have to line it some how. That being said it shouldn't be a huge deal to put a PVC liner in it but then you have to insulate it as well so you will have some money tied up...

K

 

[Blofeld69]

its been painted, its not enough?

 

[kopeck]

its been painted, its not enough?

I don't know of any paint that can take being submerged in 200 degree water for any amount of time. I guess you could drain and touch up every year or two...

You will also have to use some sort of heat exchanger.

K

 

[Blofeld69]

or I found this one a lot cheaper. It was originally used for heating oil, the seller says its been cleaned and is rust free...would this work?

 

[hobbyheater]

(broken link removed to http://www.americansolartechnics.com/heatbank1100.html)

 

[Blofeld69]

I am in Europe and on a budget. This tank is 180 bucks

 

[hobbyheater]

I am in Europe and on a budget. This tank is 180 bucks

I have the plans for building your own soft tank , the plans are about 12 pages long so it will take 2 posts .
If you want I will post them !

 

[Blofeld69]

yes please!

 

[maple1]

Will this be for a pressurized or non-pressurized application?

Big difference in the tank you'll need - and I don't think you've mentioned yet.

(Either way stay away from oil tanks...)

 

[hobbyheater]

 

[Blofeld69]

thanks. it will be non-pressurized

 

[hobbyheater]

It has been recommended that pressure treated lumber be used,and stainless steel fasteners .
Also today there are much better liners than EPDM , and I'm sure the company that I linked above would put you onto them.

 

[kopeck]

Build your own tank/frame and then get the liner from Tom, that would keep the shipping down.

What are you going to be using for exchangers?

K

 

[Blofeld69]

What do you guys think of a rubber tank? This is german made and 4600 litres so 1215 us gallons

 

[peakbagger]

Most "rubber" tanks are synthetic and few are rated for high temperature. From personal experience even tanks rated for high temperature occasionally fail. There is a lot to be said for a welded PVC liner rated for the appropriate temperature. Unfortunately it may be hard to get in Europe as PVC is generally not recycleable.