Abstract: A heating unit and solid fuel feeder comprises a vertical furnace having a combustion chamber for burning solid fuel, a water jacket around the combustion chamber and an exhaust chamber at an upper outlet end of the combustion chamber. A plenum box is connected to the furnace and defines an interior space. Water circulation tubes extend from an upper end of the water jacket, through the plenum and into a water tank positioned on an opposite side of the plenum. Additional water tubes are connected between a lower end of the water tank and a lower end of the jacket. Water circulates as hot water rises in the jacket and falls in the water tank. A plurality of exhaust conduits which also extend in the plenum, are connected between the exhaust chamber and a smoke box. A stack is connected to the exhaust box. Air flowing or blown through the plenum picks up heat from the water pipes and exhaust conduit. Hot water from the tank may be used as an additional source of heat or to heat domestic hot water.

Abstract: A down-draft, gravity fed, bio-mass, solid fuel burning stove or furnace comprises an upright cylindrical housing having a top cover and a fire resistant openable air-tight floor. Fuel drops onto the center of the floor through a central feed tube where it burns in the form of a truncated conical pile. A second tube surrounds the feed tube, defining with it an annular air intake passage for discharging an annular current of air downwardly on the burning fuel. A heat exchanger surrounds the housing and its inner wall defines with the housing a smoke passage for upward escape of the hot gases of combustion. Heat from the smoke passage heats the contents of the heat exchanger. A baffle in the smoke passage enhances heat transfer. The central tube and cover are removable as a unit.