Help me build an outdoor furnace to heat my greenhouse/hot tub

Nevin

I have a woodburner that has a BIG firebox. It has water coils(not domestic) inside, but is not a boiler. I want to clamp 3 Cast Iron Radiators to the top and both sides to collect heat and pipe it to my 3 buildings.

I am using 3/4" copper lines inside a 4" plastic pipe filled with styrofoam "Peanuts". The copper lines will be suspended by wooden rings that have holes drilled for the copper lines. The buildings will be heated by forced-air radiators taken from a bus. The system will be filled with 50% automotive anti-freeze, and buried below the frost line.

Each building will have a thermostat which will operate the circulator for that building. The water will be pumped from the building to the return line. Each radiator will have a manual air vent. A bladder expansion tank will pressurize the system. An in-line thermostat will run a combustion blower. It will have a pressure safety relief valve.

I plan to run the cold line to both side Radiators, and then the top one which should be hotter, and then the inside coils which should be hottest, and out to the buildings. I plan to cover the furnace with Fiberglas batts, and cover the whole thing with tin.

I appreciate any comments and input
from you guys who are much more knowledgeable
than this incurable tinkerer is.

I will add your e-mailed comments to my web page:
http://www.gardengrapevine.com/FurnaceOutdoor.html

Nevin
nhawlman@juniatataxpayers.com

hot_rod

Sounds Rube Goldburg-ish to me!

But.. Typically all the components would match. For instance the amount of heat emitter area should match, somewhat, to the amount of boiler output.

I'd worry that those radiators "glued" to the boiler, would adversly effect the boilers ability to heat them Will these be inside or outside the fire box?

Inside the firebox may cause a serious creasote producer. Outside, I wonder about the thermal transfer and condensation issues.

All that aside, do it safely, install adequate pressure relief valves sized for the potential output of this beast, move the women and children to a safe location, and up your insurance coverage

Although I would be embarassed to tell you about some of my "Rube" projects. Play safe and consider the energy bottled up in that devise. A little steam, out of control, is a lot like a stick of dynamite.

hot rod



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John Lenhart

I agree with hot rod. You might become the only guy on the block with a backyard rust-maker.Just kidding! something you could consider is a HAHSA. It stands for Heating And Heat Storage Apparatus. My father built one in our back yard when I was younger. It's a 10x10 block building with a 2x2x8 foot firebox. On top of the firebox is about 1000 feet of plastic pipe surrounded by about 3 to 4 ton of sand. The sand is the heat sink and will hold heat about 2 to 4 days. I found the address of the company that sells the plans.

Hahsa Co.
PO Box 112
Falls Pa. 18615 1-800-34hahsa
Hope this helps. Good luck

Nevin

Wright Brothers descendent

I should report that I'm an indirect descendent of the Right Brothers.
Once or twice I have also been related to the Wrong Brothers.