Just bought an isolated 50 acre property in West Virginia with 10 acres of grass, 40 acres of very mountainous big-tree woods and a small 100 year old farmhouse on it. Would like to be able to use an outdoor wood heating scheme that also gets me electricity. Much prefer to have a wood-burner that only needs to be loaded up twice a week, preferably with 15" diameter logs, 30" long. Definitely NOT going to split or chip wood to feed it. Considering: #1 a big gasifier with hot water circulation to the house and a woodgas 3 kilowatt tri-fuel generator for power, #2 a large fluidized bed burner also with hot water circulation to the house with 500 watt TEG units for minimal power, or #3 a big gasifier with hot water circulation to the house and a woodgas (muffled) pulsejet with a turbine for 500 watts power. The pulsejet idea is attractive to me due to having zero moving parts. I'm concerned with tars eventually gumming up a tri-fuel generator's valves. I have read that fluidized beds are popular in China due to being able to burn rocky low-grade coal or green wood. Thoughts?
All my experience with gasification tells me your desire to use large bulky wood will hurt you. The low efficiency outdoor boilers work on just about anything but they are a smouldering mess. The more efficient the design, such as a gasification boiler, the more attention you will need to the fuel consistency. I think you should consider a large water reservoir and twice a week fire off a well cut well dried load. Fuel prep is everything in gasification. Fuel prep is even more important for running engines. I like charcoal myself so I split the gasification process into heat from the wood stove and high grade fuel charcoal.
It sounds to me like you're looking for all the benefits of natural gas or propane, but from wood.
I am a huge fan of wood, but even if you're growing fuel wood that is calorically dense enough to do what you're doing, the physical properties of wood are going to be the limiting factor. The single best wood-fuelled option I have come across that doesn't require near-constant monitoring and at least daily feeding is a worm-screw feed pellet stove or furnace, whereby you load a giant hopper beside the furnace with pelletized wood, which is fed in small quantities into the burn chamber, where it burns at an optimal temperature before more are added.
I can't think of a wood-fired appliance that could be used as you're indicating without also being a huge fire risk, at least to itself. I mean, what does the feed system look like? Or does the half-week's worth of wood sit stacked on one side of the burn chamber to what, slowly slide in as it burns? What ensures it doesn't all burn?
Have you looked into Rocket Mass Heaters? They have the benefit of mass as thermal battery, such that the fire can burn hot, the wood and associated gases burn completely for a short time, and the mass traps the heat for slow release. If you haven't, do look into them. Also worth looking at are other masonry-based solid-fuel appliances that occur in different iterations from Russia all across northern Europe, and across the whole temperate world.
My concern, and it resonates with yours, is that a slow-burning fire will be, of necessity, a low-temperature one, increasing the generation of incomplete combustion products, including tar and soot. A single, high-temperature burn with something to capture the heat and release it slowly, or in the case of the pellet stove, a continuous small fire at the correct temperature for complete combustion, are both far superior to a soot-belching, tar-leaking low-burn.
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