Experience with / thoughts on Softank for thermal store?

[mapratt]

Hi, everyone -

Does anyone have experience with the Softank?

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

 

[pybyr]

Hi Marilyn; we in the Boiler Room all try and usually manage to be more responsive, especially to newcomers, than we've managed to be with you on this one.

Here's my take on your question:

The softank was an early design by the company you link above. My understanding is that their rectangular tanks are actually successor products that have some desirable characteristics that the softank may not. If I were going with a knocked-down unpressurized storage unit, I'd definitely go with their rectangular product.

That said, the softank configuration has been widely copied, both by commercial vendors, and DIY-ers, and used with considerable success, so it's clearly got some good features.

Also, if you have a layout that will allow you to get used propane "lawn submarine" tanks into the location for your storage, you have a potentially low-cost option that has some appealing advantages: low tank cost; savings by eliminating one or more heat exchangers; elimination of worries about tank liners that could eventually have issues; and the ability to push your storage to higher temperatures (which has the net effect of making your storage hold more "banked BTUs").

 

[mapratt]

Thanks, Trevor! I appreciate it. Silence can could mean there's a big storm everyone's battling, or no one on the forum has used it ;-). I was guessing the latter, and appreciate the balanced reply.

Lawn submarines are fine - I need to build a shed for this anyway. I just need to find a source or two; initial searches make it look like in some areas that can be a challenge.

Still learning all my options, gathering info. This is a great site; good conversations, beautiful drawings, great pictures - thanks and kudos to you all.

Careful - I'll ask if anyone has gotten into wood-fired steam-powered generation of electricity ;-)

 

[Hunderliggur]

I looked at liner tanks and propane tanks. Meaning no offense to the liner tank crew, I had some concerns with liner life at higher storage tempratures. My dream solution is to use my wood boiler with solar assist in the SUMMER to run an absorption chiller. You need HOT(180 - 210) water for this. Most high temp liners are spec'd in the 180's. Also, the liner has a life (temperature dependent) which I did not want to experience in my basement. In your case, you could provide a "drain pan" under a liner tank and pipe it outdoors.

The people having problems finding tanks are Canadians mostly. Must be some Canadian law or regulation that keeps them from reselling old tanks.

If you are doing storage in an out building, be sure to consider the Garn unit with integral storage.

Good luck and welcome.

 

[killick]

I looked at liner tanks and propane tanks. Meaning no offense to the liner tank crew, I had some concerns with liner life at higher storage tempratures. My dream solution is to use my wood boiler with solar assist in the SUMMER to run an absorption chiller. You need HOT(180 - 210) water for this. Most high temp liners are spec'd in the 180's. Also, the liner has a life (temperature dependent) which I did not want to experience in my basement. In your case, you could provide a "drain pan" under a liner tank and pipe it outdoors.

The people having problems finding tanks are Canadians mostly. Must be some Canadian law or regulation that keeps them from reselling old tanks.

If you are doing storage in an out building, be sure to consider the Garn unit with integral storage.

Good luck and welcome.

I see where the source listed in the link above now has a liner available capable of prolonged 200 degree storage temperatures. As a Canadian I am experiencing first hand the frustration of finding propane tanks for pressure storage. The propane companies will not sell them and salvage companies don't handle them. Classed as dangerous goods I believe. I am reconsidering using open storage for my needs.

Earl

 

[tom in maine]

Since this thread relates to one of our products, just a couple brief comments.
We are in the process of changing over to a new liner which is similar to the one that we have used
for about 30 years.
It is rated at 200F continuous exposure and tolerates boiling very well.
Our "acid" test is boiling the liner every day. We have done this for about four months, cycling from boiling for several hours a day
(it gets steamy in here!) to a low temp of 180F before re-heating.

There is no deterioration of the liner in these simple extreme tests. This material already has a pedigree of being able to tolerate
200F with no ill effects. Boiling a liner, any liner, really stresses it beyond what might be considered normal for the applications we use them for.

This is an inert material that does not break down and is a thermoelastomer that we have custom formulated for us.
We have been testing it for over seven years.

Looks good.

 

[Hunderliggur]

Gret to hear you are working on higher temp products. I bet you will get a lot of takers. If I ever decide to add more storage I might go that route.