Hybrid wood burning fireplace assembly

A hybrid wood-burning fireplace assembly configured for burning wood-based fuel, wherein the burning generates combustion exhaust, the assembly comprising:

• a fire box having an interior area, a base portion, and a top portion with an exhaust outlet;
• a baffle in the interior area defining a lower combustion chamber below the baffle and an upper combustion chamber above the baffle, the upper combustion chamber having an upper exhaust passageway between baffle and the top portion of the firebox;
• a primary combustion airway having an inlet that receives primary combustion air therein and having at least one outlet in the firebox that directs the primary combustion air to the lower combustion chamber for primary combustion with the burning wood-based fuel;
• a secondary combustion airway having an inlet that receives air therein for secondary combustion of at least portions of exhaust from the burning wood-based fuel in the lower combustion chamber, the secondary combustion airway having air outlets in the firebox that directs the secondary combustion air adjacent to the baffle to mix with the exhaust for non-catalytic secondary combustion of the exhaust before the exhaust flows through the upper exhaust passageway;
• and
• a catalytic combustion unit in the firebox and supported on the baffle spaced apart from the exhaust outlet and across the upper exhaust passageway whereby the exhaust will pass through the catalytic combustion unit after the non-catalytic secondary combustion of the exhaust and before the exhaust exits the upper combustion chamber through the upper exhaust passageway;
• wherein the air outlets of the secondary combustion airway are sized and positioned as a function of a size of the firebox, a desired oxygen level for mixture with the exhaust gasses prior to secondary combustion, and the catalytic combustion unit to provide;
• and
• wherein the combustion exhaust entering the exhaust outlet has a maximum particulate emission level of up to approximately 1.0 grams/hour.

A method of reducing emissions from a wood-based fuel burning fireplace assembly, comprising:

• burning a wood-based fuel in firebox of the fireplace assembly during primary combustion of the fuel to generate exhaust with particulates therein, the fireplace assembly having a baffle in the firebox that divides an interior area into an upper combustion chamber and a lower combustion chamber, the upper combustion chamber having an upper exhaust passageway between baffle and a top portion of the firebox;
• directing secondary combustion air into the lower chamber below the baffle for mixing with the exhaust for secondary combustion of the exhaust in the firebox;
• burning particulates in the exhaust in the secondary combustion adjacent to the baffle;
• passing a first portion of the exhaust after the secondary combustion through a catalytic combustion unit positioned across an exhaust passageway in the upper combustion chamber above the baffle, wherein passing the exhaust through the catalytic combustion unit removed additional particulates from the exhaust after the secondary combustion;
• passing a second portion of the exhaust after the secondary combustion through a bypass to an exhaust outlet in the firebox whereby the second portion of the exhaust does not flow through the catalytic combustion unit and
• directing the first portion of the exhaust out of the firebox through the exhaust outlet after the first portion of the exhaust exits the catalytic combustion unit and passing the second portion of the exhaust through the exhaust outlet after the second portion of the exhaust exits the exhaust bypass.