The AVUD gasification technology is pioneered and commercialized by Chip Energy. It is called “Another Variation UpDraft” because it has some critical features that distinguish AVUD gasifiers from traditional updraft gasifiers that do not function well at very small sizes.  The diagram shows the basic structure of the gasifier up to the location of the combustion of the gases. 

Fuel is added from hopper onto fuel pile above grate Fuel is top lit with lighter fluid Air enters upward through fuel Hot smoke fills the "smoke maker" above the fuel Air enters the "smoke burner" for clean combustion of the smoke rising from the smoke maker Used fuel becomes hot char and keeps the in-coming raw fuel heated to release smoke (pyrolysis gases) Openings for lower secondary air help control draft Ash and excess char are released after build up

Above the combustion zone are the many different applications of the heat (grill, cookstove, room heater, water heater, fruit dryer, and other process-heat divices).  Therefore the final physical appearances of the whole structure can be extremely different.  But inside, Chip Energy’s AVUD gasifier works basically the same for any application.   [For commercial reasons, some critical features essential for successful AVUD micro-gasification are not fully explained here.]