[Stoves] Coal Heater

[Crispin Pemberton-Pigott]

Dear Jeff

>Is a coal fired hydronic heater with flue pipe out of line?

Nothing is off the books as far as I am concerned. What we have shown so far
is that while retaining pretty much the basic layout of a traditional stove,
we can get emissions down an order of magnitude without changing the fuel.

If you are familiar with the vertical two concentric pipe paraffin fired
water heaters such as the 'Geyser 2000' it is possible to integrate the
water heater into the chimney. They are very efficient actually, despite
their simplicity.

What does not work so well for solid high carbon fuels is a cold wall. The
combustion needs to take place over a relatively long time because it seems
to take a while (meaning physical distance) to get the carbon pulled apart,
mixed and burned to completion. 

There is a coal source called Baganuur which has a young oily coal that
definitely takes longer than usual to burn well. The solution so far is to
run the fire inside a 2-1/2" pipe for more than 2 feet. It works very well
with a CO.CO2 ratio holding below 0.1%. I was unable to get that result
using an open architecture (like a regular stove with a fire at the bottom
of a box). Maybe if the temperature were raised even more....

Regards
Crispin