A combustion system, said combustion system comprising:
- a biomass burner that includes:
- i. a firebox,
- ii. a firebase at, or forming, a bottom of the firebox,
- iii. a primary combustion zone for pyrolyzing and combusting the biomass fuel, the pyrolyzing and combusting of the biomass fuel producing gases and particulate matter,
- iv. a first air supply having a first air pathway connected into the firebox to thereby supply primary air into the firebox,
- v. a secondary combustion zone for combusting the gases and the particulate matter produced from the pyrolysis and combustion of the biomass fuel,
- vi. an exhaust flue with an upper part that extends out of a top of the firebox and a lower portion that extends into the firebox to a location above a first portion of the firebase and adjacent a region of said secondary combustion zone,
- wherein the firebase includes a charcoal/reduction layer support region, the charcoal/reduction layer support region supporting a charcoal/reduction layer which forms below the primary combustion zone, in the region of the secondary combustion zone, and between the primary combustion zone and the secondary combustion zone,
- the secondary combustion zone being at least partially surrounded by the primary combustion zone,
- wherein an opening of the lower portion of the exhaust flue is located above the first portion of the firebase, the first portion of the firebase including a first part of the charcoal/reduction layer support region included in the region of said secondary combustion zone in which the charcoal/reduction layer is formed,
- wherein the gases and the particulate matter produced from the pyrolysis and combustion of the biomass fuel in the primary combustion zone pass over, or through, said charcoal/reduction layer and over said charcoal/reduction layer support region including the first portion of the firebase, prior to entering the secondary combustion zone and the opening of the exhaust flue;
- and
- a second air supply comprised of at least one aperture, each aperture having an inlet directly exposed to atmosphere, each aperture extending through the first portion of the firebase and having an outlet located below a lower surface of the charcoal/reduction layer in the region of the secondary combustion zone to thereby introduce a secondary air drawn from outside the firebox, through the at least one aperture, and discharged into the firebox at the first portion of the firebase below and through the charcoal/reduction layer in the region of the secondary combustion zone,
- wherein the secondary air, being discharged through the at least one aperture below a lower surface of the charcoal/reduction layer in the region of the secondary combustion zone, is heated by passing through the charcoal/reduction layer and the secondary combustion zone, as the secondary air is being introduced into the firebox, above 600° C. and maintained above 600° C. at a temperature sufficient to combust the combustible gases and the particulate matter in the secondary combustion zone.