[Gasification] Cold Inlet Air Observations

[Greg Manning]

Greetings all,

This past "cold snap" (down to minus -30's, and -40's for us) has had quite
the effect on us as a family it has been so cold, for so long, that I had to
go down to the barn with booster cables, to "jump start" the mice, so the
cats would have something to play with....

Ok, seriously though, there appears to be a "finite low point" for wood and
raw outside air to burn correctly.

We have an "wood fired outdoor boiler" that we use to heat water that is
circulated in underground, insulated pipes, to our home and my shop.

At minus -20c or so, I can still get a fire to the point of heating the
transfer water to 80c area, BUT, when the outdoor air dips to the minus -30
mark, it gets real tough to get the fire to heat the water to anything over
70c, and when the air gets to -40, it's down to 60c or so for water.

This is with wood all from the same lot, cut and dried the same time, etc.
etc. etc. The only change is simply outdoor air temperature, which has 
forced
me to do the obvious,set up an inlet air heat exchanger.

This extra "grab" of temperature (at the flue) has had a somewhat negative
effect on the units operation (even though the incoming air is now warm...

It appears that with the lower flue temperature, the chimney does NOT draw 
as much as it use to, forcing me to run the startup fan as a push unit to 
keep the burn rate up, so even though the incoming air is warmer, the 
chimney is colder. I would assume that another 3ft of so, of chimney would 
create more suction, therefore bringing the airflow rate back to acceptable.

I guess in this case, it's "Energy Modeling" that I would have to do, to see 
the reasons, and find answers that would bring everything back to correct 
burn parameters that I had before this all started......

O'well, it's time for a new "slide rule" anyhow.

Greg Manning