Abstract: The application discloses improvements in a combination solid-fuel-burning, liquid heating and thermal energy storage apparatus in which a firebox is immersed in a large tank for heating the liquid stored therein and in which an improved flue assembly carries gaseous combustion products from the firebox through the tank liquid to an exhaust stack which has an outlet outside the tank. A blower draws combustion air into the firebox, draws the resulting gaseous combustion products through the flue assembly and provides a forced discharge of said combustion products through the stack outlet. The blower preferably includes a rotary fan in a fan housing which is serially connected in the flue assembly and positioned within the liquid inside the tank to provide a heat exchange housing enhancing the transfer of thermal energy from the combustion products to the surrounding tank liquid and minimizing possible high temperature damage to and excessive wear of the blower parts.

Abstract: A wood-fired boiler and hot liquid storage system includes a top-vented storage tank for the liquid, a firebox supported within the tank at a level for complete immersion within the liquid, with the bottom of the firebox spaced above the bottom of the tank, and with a firebox end opening in liquid tight engagement with the edges of a corresponding tank side wall opening, and a firebox door for selectively closing the opening and permitting introduction of solid fuel. Combustion gases from the firebox are discharged through an open vertical stack extending up through the tank and liquid to an outlet opening outside the tank. Preheated combustion air is introduced at the firebox opening and fed by forced draft through the firebox and stack by a blower. The preheating is provided by a special firebox door construction in which incoming air passes between inner and outer walls of the door and is preheated by the hot inner door wall while it also keeps the outer door wall at a lower temperature.