Disclosed are a gas furnace and an air conditioner having the same. The gas furnace includes: a burner for burning fuel; a manifold providing the fuel to an entry of the burner; a heat exchanger spaced apart from an exit of the burner and providing a passage for combustion gas generated by the burner; an inducer for causing a fluid to flow through the burner and the heat exchanger; a blower for causing a flow of air passing around the heat exchanger; and an air shutter positioned between the manifold and the entry of the burner. The air shutter includes: a housing having an inner space that communicates with the manifold and the entry of the burner; and a primary hole formed to penetrate the housing and able to be opened and closed.

A coal-fired power generation system may include a boiler outputting flue gas, a coal pulverizer associated with the boiler, and a heat exchanger. The heat exchanger may be configured to exchange heat from the flue gas to a primary air path and a secondary air path. The primary air path is coupled to the coal pulverizer, and the secondary air path is coupled to the boiler. The coal-fired power generation system may include a controllable air recirculation path coupled from an output of the primary air path to an input of the secondary air path.

A coal-fired power generation system may include a boiler outputting flue gas, a coal pulverizer associated with the boiler, and a heat exchanger. The heat exchanger may be configured to exchange heat from the flue gas to a primary air path and a secondary air path. The primary air path is coupled to the coal pulverizer, and the secondary air path is coupled to the boiler. The coal-fired power generation system may include a controllable air recirculation path coupled from an output of the primary air path to an input of the secondary air path.

Exemplary embodiments of a system and method for bimodal air control in a kettle-style grill are configured to be detachably mounted to the exterior of a kettle-styled grill such as, but not limited to, a Weber® charcoal grill. When mounted to the kettle-styled grill, a plenum-like component directs air flows to the interior of the grill's kettle via the kettle's lower body damper holes. A manually adjustable intake damper in the plenum component allows, restricts, or prevents a drawn ambient air flow into the plenum component. Separately, a forced air flow generated by a fan may also be provided into the plenum component. Adjustment of the intake damper may also adjust damper blades inside the grill's kettle. Ash that falls out of the kettle's damper holes falls through the plenum component and is captured in an ash receptacle that is removably mounted to the plenum component.

A method for burning a fuel in a wood stove having a door to a combustion chamber with a base, which combustion chamber is isolated from the air by an exhaust and an intake at which intake there is provided an air regulator having at least primary, secondary and tertiary air intake ducts. The stove is controlled by a burn controller configured to operate between the different operating, i.e. different combustion states.

A method for burning a fuel in a wood stove having a door to a combustion chamber with a base, which combustion chamber is isolated from the air by an exhaust and an intake at which intake there is provided an air regulator having at least primary, secondary and tertiary air intake ducts. The stove is controlled by a burn controller configured to operate between the different operating, i.e. different combustion states.

Disclosed herein is a combustion apparatus which comprises a chamber having a apertured rotatable tubular auger mounted between end walls of the chamber to convey particulate material from the region of the chamber proxi-mate the feed inlet to the combustion gas outlet and a blower connected to the opposite end of the tubular auger and configured to blow gas into the bore of the auger and out through the apertures into the chamber.

Disclosed herein is a combustion apparatus which comprises a chamber having a apertured rotatable tubular auger mounted between end walls of the chamber to convey particulate material from the region of the chamber proxi-mate the feed inlet to the combustion gas outlet and a blower connected to the opposite end of the tubular auger and configured to blow gas into the bore of the auger and out through the apertures into the chamber.

An opening is defined in a wall, the opening defining a plurality detents along a lower edge thereof. A vent cover affixed to the outer wall such that the vent cover is rotatable to cover and uncover the opening. An indexing mechanism selectively fits into each of the plurality of detents and retain the vent cover from rotation.

An opening is defined in a wall, the opening defining a plurality detents along a lower edge thereof. A vent cover affixed to the outer wall such that the vent cover is rotatable to cover and uncover the opening. An indexing mechanism selectively fits into each of the plurality of detents and retain the vent cover from rotation.