wood heat

 This may not be the right group for this question, but here goes.  I
have a 21wide x36long x20high greenhouse that is killing me on propane
heating costs and it's not even winter yet here in Tennessee.  I have
20 acres of wood with lots of dead wood.  Even buying wood would cost
a small fraction of the propane we're going through.  I've been
thinking of building a cinder block or firebrick "stove" to use on
cold nights to supplement the propane.  I've looked on the net but
haven't found what I'm looking for.  Before launching into the design
and building I hope to get some input from folks that know about such
things.

I thought about basically a stone box with a iron cover and stove pipe
chimney with damper.  A door on the front with a way of limiting air,
or a vent from outside to furnish oxygen for combustion.  The floor of
the greenhouse is dirt so the stove could be build directly on the
ground or a layer of firebrick.  The plan would be to load it up with
wood at bedtime and close the damper to slow down combustion.  The
brick would heat up and radiate warmth to the greenhouse until solar
would take over at sunup.  Any comments or sources of info would be
appreciated.

Any other groups that I could post this to?

Thanks,
Harry

  My son worked for a farmer that did this. He stoked up the fire and
pumped hot water through tubing grillwork in the ground of the plants
in the greeenhouse, each day, heated the earth  up and it really makes
the plants grow too. The large thermal mass of the soil holds the heat
quite well until the next day or so. The woodstove was outside and
designed for it.

You will need steam blow-off valaves and expansion tanks and other
serious equipment as this can be dangerous. Woodstove heaters are
common to buy but expensive. I believe proper woodstove heaters are
designed with all the bells and whistles for this application. Just
need a couple of manifolds and lot of PEX tubing that you can get off
eBay for much cheaper than the supply houses. The pump may be in the
unit.

 

Hello Harry

Could this principle be a solution ?
http://www.vtbrickoven.com/masonry/masonry.html

The mass stove is used more and more in this country.
It is cheap, simple to build and very efficient.

regards Niels

 

Is that the same as a "Russion fireplace"?

 

I don't think so.
The stove I know is also called a Finnish stove (Invented in Finland ages
ago)
The special thing about a Finnish stove is that it has a relatively large
firebox.
You fill it completely with wood and light it at the TOP of the wood pile.
This gives a controlled and very clean burn with no creosote because the
gasses are heated to a very high temperature.
Efficiency around 80%

regards Niels