Water storage options....

[brad068]

I am using a 30 plate, 5" x 12" HX, with 1" in/out ports, on my Tarm Solo Plus 40. The HX cost just over $200 on Ebay. The boiler loop powered by its own pump uses antifreeze, and the storage loop powered by its own pump is about 800 gallons of water (3 - 275 gallon old fuel oil tanks in series, got them for $125). The tanks are vented and not pressurized. I have a diversion to a unit heater for immediate heat when needed. Otherwise, the three steel tanks function as large radiators and provide heat without any blowers, fans, etc. All of this is installed indoors in my wood-working shop (20' x 40' x 10'), poorly insulated. The HX takes all the heat the boiler can deliver with less than a 5 degree temperature drop, in other words, 160F into the HX and 155F or more out to storage. A surface mount thermostat on the boiler return line turns on both pumps when the return temperature reaches 150F, and both pumps shut down when return temperature falls to about 140F. This occurs only when the boiler has burned its wood load. In about 8 hours of burn time, with outside temperatures around 10F, the water storage will be brought from about 80F to about 150F. The steel storage tanks, acting as radiators, then heat the shop for 1 to 3 days depending on outside temperature.

jebatty,
Your radiant system is about the same as my situation right now. My homemade Garn principle boiler is setting in my repair shop, (40'x48'x12'H) and is radiating most of its heat into my shop. The tank is a 1500gal milk tank that has about 1300 gal. of water storage, minusing firebox and flues. I have been firing mine about every 36hrs. I fire at 135-140 and usually raise it to 190 with a smaller wheelbarrow full of wood that is not seasoned at all. When it gets up above 30*F and boiler above 150*F, its almost to warm to work in the shop without opening a window. I have future plans to install and insulate the boiler in a separate structure before next heating season.

 

[Eric Johnson]

Thanks for explaining your storage setup, jebatty. No need to do it again in the other thread.

 

[Gooserider]

As a thought for heat exchangers - has anyone thought about using automotive / truck radiators or heater cores? At least the older ones are copper, fairly low cost, and are good for about 25psi of pressure, maximum, should be run at no more than 15psi... Seem like they should be able to pass a pretty high volume of water with low restriction, at least they do in a vehicle... I would think putting one near the top of the tank for the extraction loop and one near the bottom for the charge loop might be a very effective setup.

Gooserider

 

[jebatty]

I had one of these in operation, worked well. It just wasn't pretty. Used a large squirrel cage fan behind an old truck radiator. I replaced it with a used unit heater, mostly because the unit heater fan took much less electricity (and it looked better).

 

[Eric Johnson]

I think he's talking about an intank water-to-water hx, Jim. I know slowzuki was talking about the same thing for basically the same reason.

My only concern is that a new truck radiator is probably mucho dinero, and I'm not sure I'd be comfortable using a used one, not knowing what it's been through.

How about cast iron?

 

[jebatty]

never mind . . .