mikeyny said:
I have access to lots of hardwood chips from a chip truck. The tree guy will dump all I want. I k now there are commercially made chip boilers out there but they are big bucks. Anyone build their own? I have some materials and some fabrication skills, and Im thinking about experimenting with it. Naturally most of the chips will be green and wet. There is no practical way to dry chips in volume that i know of so burning as is would be part of the challenge. Any thoughts?
Chips are usualy burned green as you noted.
As a result, a lot more chips are used.
Efficency in fuel use generaly doesn't enter the equation until fuel cost becomes an issue.
Nevertheless, being able to dry the chips at all would reduce the resulting polution as well as amount of fuel used.
I have long envisioned a system where the chips are fed into the burner through the exhaust stream, possibly drying at least some.
Enough philosophy.
You will need a self clearing hopper and an auger or some other mechanism to deliver chips.
You will need to be able to regulate the volume of chips delivered, and since the moisture content IIRC will be about 50%, you will likely need to supply
forced combustion air. Not sure about that though.
As an aside, since you want to go down this road anyway, there would be a lot of overlap between a chip boiler and a wood gas producer.
Using the flamable gas from a wood gas producer, one could power a water-cooled internal combustion gen-set.
The internal combustion engine would be your "boiler", using a heat exchanger the engine coolant could heat your home, charge your storage tank or whatever, and the electricity you generate, through net metering could power your home year round, even though you only run it during the heating season, if the gen-set were sized correctly.
Wood gas producers are well established technology at this point, with a hundred year history, and can be bought "off the shelf" or built by a handyman with some fab skills.
Sized correctly, you could even charge electric cars and be energy independent, all from free woodchips, without the work involved in cordwood.
There is lots of info on wood gasification on the web.