[Stoves] Chimneys

Mon Nov 1 14:49:32 CDT 2010

Dear Kevin

Thanks. The data coming out of the lab in Ulaanbaatar us amazing to behold.
We are getting information as good as that on real time particulates PM 1.0,
PM 2.5, PM 4.0 and PM 10.

I know about this thermal efficiency issue long ago as did many others. As
has been shown (not to me though) a fireplace has very little to contribute
to a home if it is made the way the pioneers did it. Terrible excess air
pulling cold air into the house and cooling the room. You know the campfire
story about roasting in front as you face the fire and freezing behind where
there is no heat. Welcome to the log cabin.

>Would a simple bimetal magnetic stack thermometer be able to tell you the
temperature of stack gases, 

Even deleting the rest you have a good suggestion. It is not that it should
be an indicator, it should be a controller. The automatic choke control on
any gasoline engine works the same way: heat a spring (usually heated by the
engine water) and the coil opens the choke.

What I find is that there has to be a lower limit on the choking or there
are gassing risks. And if it runs on heat alone, it needs to be held
manually until the fire is going. That is not a big issue. I think the fuel
saved in a single season will easily pay for it.

The first problem though is the oversized chimneys. They are simply too
large for domestic heating requirements. I am not sure where they came from.
Maybe it is all about being big enough to be clogged a lot and still work.
In other words it is an anticipation of poor combustion. People in UB report
having to clean their chimneys every two weeks. I found that incredible!
That is really, really bad combustion. But they blame the fuel.

A thermo-actuated damper could conceivably save 20% of fuel or more.

Regards

Crispin

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20101101/93322c56/attachment.html>