Bear with me.
I'm considering designing a
rocket stove underneath a 240 gallon steel vertical
water tank. It will be filled with water. It will operate similar to a natural gas
water heater except the burner stays on. A flue pipe will be welded thru the center and have secondary air for the first 3' of the flue, and my hope is that the water will absorb the majority of heat, such that stack temperature declines before it exits the wall thimble and be around 250 degrees F or less. I plan to put an air water heat exchanger and water recirculation pump, with a fan that can blow the heat into my shop. I considered using a large automotive radiator because they're designed for this purpose.
My shop is 35'x 55' with 20' ceiling.
The primary advantage that I can see is, once the water is heated to a temperature of 130 degrees, the thermal mass of the tank itself
should continue to provide heat whether the fire is burning or not. I can add external insulation to the tank to increase the thermal retention.
It'll be trial and error to determine how long post fire, the heat will last being circulated, perhaps all night. Which means I would only have to fire the stove once a day, and not continue to add
wood.
Based on a chofu style wood fired hot tub outside, 50 degree water would be raised to 105, in 3-4 hours. I'm guessing 5-6 hours of primary burn per day. This would save a ton of wood instead of having to keep the stove running constantly.
A friend gave me a 240 gallon well storage tank, its beefy. 400 pounds. 32" diameter and 78" tall, 3/16" steel.
I'm a retired pipe welder, so the fabrication aspect is not an issue.
There's a minor additional advantage that if I choose to put a wood fired hot tub in, theoretically I could just plumb it to the tank.
What do you think?
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