Storage Tank Idea!

[Dean_O]

So for the last several months I have been putting together on paper a heating system that would hopefully be efficient and would utilize the full potential of the equipment that has been chosen, while also trying to be keep the bottom line at a reasonable level. I have calculated out my needs and I am pretty sure I have done a decent job of determining our heating loads for our house. I have used several resources for these calculations from this website, and I couldn't be more grateful for all information that is on here!

So I have purchased the wood boiler that I feel like will give me the best service and longevity, It hopefully will be delivered within the next week or so. I chose to use the Portage and Main EGR 100 for my heat source. The calculations that I came up with for storage was around 800 gallons, so I have been looking for storage tanks that I could utilize, and I remember a tank that my wife's uncle had sitting outside his barn.
i couldn't believe what I had found, and I think it is going to be a really good option.
I had remember that this tank was stainless but didn't really remember anything else about it, upon looking it over it was an old refrigerated milk tank that had been disassembled and used as a watering tank. It just so happened that it was 800 gallons! Woo Hoo also it was insulated. I was so excited at the find that I didn't even realize there was another benefit to this vessel.
There where 4, 1/2 inch copper lines sticking out the end of the tank that where used for the refrigeration coils that jacket the tank. My question is do you thing these coils would be sufficient for heating the water in the tank?

 

[Bob Rohr]

Any data on the tank that would help determine the length of those copper loops? What is the actual output of the Portage? That would help determine the flow rate that you need to build around.

Nice about the dairy tanks, they usually have a large manhole to allow you to install coils inside. Copper or CSST makes for some nice high capacity coils.

 

[Dean_O]

I can't find much information on this tank online due to the age and the company being out of business.
Here is what I know
Water tank
102" long
60" wide
800 gallon
Model #921-4
Wv800
Zero tank

 

[Dean_O]

The Portage has an maximum output of 125k BTU.

 

[huffdawg]

Will your system be open or closed?

 

[Bob Rohr]

When dairy tanks like that get removed around my area, it is often because the refrigeration side leaked or failed?

Maybe get the coil spec on a similar tank of another brand.

You could evacuate the coil with compressed air, fill with water, purge air out, then empty into a bucket or two to get an idea of how many feet of coil.

If you determine the id of the tube you can look up fluid capacity of the tube.

 

[maple1]

This might be what huff was getting at - but with an open boiler, and open tank, I would likely consider hooking them both up directly, and using the coil as a HX to run the system water though. I.e., not to heat the water, but to draw heat with. Can you tell exactly where the coils are situated? Are they all around the tank? Or just on the bottom part? If they don't get to the upper reaches, you would lose some effectiveness from them not picking up the hottest part of the tank, unless you took to mixing the tank water up.

If things are still intact, that is. Hopefully they are - should make for a nice setup. Time for some pressure & leak testing, me thinks.

 

[Dean_O]

I will hopefully have the tank back at my house this weekend. I will pressure test and determine the length of the lines as soon as I can.

I was really thinking to use them to heat the water possibly, just to keep the boiler water volume as low as possible to keep treatment cost down. Is this not good practice? That would keep the boiler water sealed, and the heating circuit water could be open.

 

[maple1]

The P&M boiler is an open boiler - correct? So it won't be 'sealed'. But yes, if you can keep the boiler water volume to just that, you would certainly need less treatment. You would still need a separate HX between the tank & heating system though - you don't want the heating system to be open. Usually too many things there that you don't want to expose to corrosion potential. Plus some pressure is usually good to get & keep water flowing to where it needs to go in the system. So my thoughts were moreso to possibly eliminating a heat exchanger than anything else

 

[peakbagger]

I used to date a girl in northern VT and there were a lot of old dairy farms that had stopped milking as they were too small. Lot of old brans with these tanks in them. I always was looking for one on sale at the side of the road but wasn't sure where I was going to be living so I never pulled the trigger. Hard to beat them. The ones I looked at had refrigerant coils but they were generally too small. I would suggest contacting American Solar Technics (TominMaine on this forum) and see if he can make a custom coil that will drop in the manway.

 

[Dean_O]

Update, I finally got my tank home! After doing some investigating and testing the built in coil is not going to work. It only covers the bottom of the tank, and it did not pass a pressure test. Oh well, I will just make my own internal heat exchanger.


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