Nice TLUD design. Looks like it will hold up well.
I use a flame-cap biochar system. Not the "best" system, but certainly the most popular.
My friend
Josiah Hunt's (JH in photo) initial approach to making biochar. Apparently, now most people's initial approach.
This is my main way to make biochar. It takes pyromantic intent to pull this off. The flame-cap systems are widely used around the Pacific Rim and are popular throughout the timbered western US and Canada.
Flame-cap systems are not as clean-burning as enclosed biochar systems. It is critical to the earth's health that the flame-cap charista discriminates in the fuel sizing and holds off on a flame-cap kiln burn until ideal fuel/weather (RH, moisture, temperature, wind) conditions. This attention to detail is needed to assure minimal smoke and eliminate fugitive losses of methane and nitrous oxide, invisible but powerful
greenhouse gases. These can escape destruction in the flame cap due to wind stronger than the draft into the cap or insufficient draft from a cooler flame cap from cold, wet, or oversized fuel.
Done right, a flame-cap system quickly makes a bed of pure glowing embers which you then snuff with dirt, or dowse with
water (or snow) to hold the char. Very approachable, popular, scaleable, gets the job done for people who grow for a living. Satisfies that need to watch fire at work.
Josiah Hunt: How to make biochar with only a match (2013)