Planning water storage. How to size the take?

[RDabate]

Hi guys,

I'm planning the next steps and I'm looking to add water storage to the mix. I'm not a do it your self-er as I lack the heating knowledge, so I'm not going to make one like a lot of you guys do. I do not have a walk out basement, so I would need to get the tank down through the bulk head. I'm heating about 2800 sq ft, baseboard. I'm looking at the 820 Gallon Heat Bank from the link below. Do you guys think this tanks is big enough? Or maybe it's to big? Or maybe there is a better option?

http://www.americansolartechnics.com/820.html


Any suggestions would be great.

 

[sparke]

Definitely not to big. The owner of that company (Tom) knows his business, you are in good hands. As far as another type of tank , your best bet is to find a used propane tank... It took me about 3 years but I finally found a nice pressure tank on craigslist for $200.

 

[bigburner]

I have some open storage, if I did it all over again I would use pressurized-- put a ton of money into the open tank and chemicals to deal with and evaporation. If you are never adding solar!! If you pull out the stairs & bulk head, a 500 gal might fit, for sure a couple 250 would. I ended up with 4,000 gals open, but I was trying to buy a 12,000 pressurized bulk tank, that might have been the record here. LOL

 

[RDabate]

Unfortunately, my stairs are cement. That's why I don't think I'll be able to go with pressurized storage, and that's why I was looking at storage tanks like this.

 

[DaveBP]

If I were going with non-pressurized storage, American Solartechnics is the first (and only) place I would talk to.

 

[ewdudley]

Unfortunately, my stairs are cement. That's why I don't think I'll be able to go with pressurized storage, and that's why I was looking at storage tanks like this.

Check out the modular pressurized units, e.g. the Aqualux advertised by smokelessheat.com on this site. They look like they would fit down most all basement stairs. They look expensive but are purpose-built, 'feature-rich', and pre-insulated.

Also you may be able to find a fabricator locally that could build a couple pressurizable units custom designed to fit down your stairs for less money than you might expect.

As for size, you may have a nice advantage with your smaller boiler. An appropriately sized boiler will burn the fuel load slowly enough such that a lot of the heat is stored in the wood waiting to be burned. With a big boiler you're in a hurry up and wait situation with a lot of heat now that needs more storage to accommodate.

--ewd

 

[stee6043]

Describe your access to the basement. Sometimes temporarily widening a door frame or modifying a wall can actually be a LOT less expensive than a non-pressurized tank setup. For reference propane tanks range in widths from 32"-37" at roughly 120" long (500 gallon)...

 

[pybyr]

If I were going with non-pressurized storage, American Solartechnics is the first (and only) place I would talk to.

Agreed. And while the 820 is their standard size, I think that they can readily bump up or down in size.

As to sizing, 8.34 BTU will raise one gallon of water one degree F. Similarly, you can extract that amount when you pull a gallon of water down one degree F.

Figure out the highest temperature to which you can safely/ feasibly charge your storage. EPDM lined tanks can't go above 180, some say it is best to not go above 170. I think I recall that the American Solartechnics tank can safely go to 190 or 200, but you should check.

Pressurized storage may give you the option to push the top temp considerably higher.

Then figure out the lowest temperature at which your baseboards can put out useful heat.

That "useful temperature swing range" and the figure of 8 BTU/ gallon will give you an ability to ball-park how much storage a given number of gallons will actually give you.

Also figure in the fact that heat exchangers will be less than perfectly efficient, and that you will have losses from the storage and from the piping to and from storage (less of an issue if it is all in a space that benefits from heat given off).