Comparison of Phase II EPA Certified Stoves to Low Mass and

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					Comparison of Phase II EPA Certified Stoves to Low
         Mass and Masonry Fireplaces




          Dan Henry
                        EPA Phase II Certified Controlled Combustion




  HEATED CON-
  VECTION AIR
                                                        BAFFLE
                                                        INSULATION

                                                         EXHAUST

       FIREBRICK                                        BAFFLE

                                                         SECONDARY
   PRIMARY AIR                                           AIR


AIR CONTROLS                                             CONVECTION
                                                         AIR

                                                        AIRWASH AIR


                                                        INCOMING CON-
                                                        VECTION AIR


                   ASH PAN ACCESS
                       EPA Phase II Certified Controlled Combustion



• Stack Flow Rate
  – High Burn under 20 cu. ft/ min
• Air Limited, Controlled Combustion
  – Air to Fuel ratios 10 - 14:1
• High Firebox Temperatures
  – Helps to Initiate and Sustain Secondary Combustion
• Limited Firebox Volume
  – 1 - 5 Cu. Ft.
• Woodstoves are Heating Appliances
  – Less Frequent Fueling with Full Firebox Loads
  – Typically 24/7 Burning Cycle
  – Frequent to Constant Use during Heating Season
                      Low Mass Open Burning Fireplace




                                        DAMPER




        SMOKE SHELF

                                         AIR SPACE




UNCONTROLLED                            FIREBRICK
AIR FLOW                                PANELS



                                       GRATE
                      Masonry Open Burning Fireplace




                                 SMOKE SHELF




                                    DAMPER
                 LINTEL


UNCONTROLLED                       FIREBRICK
AIR FLOW

                                    HEARTH

     HEARTH                       ASH CLEANOUT
     EXTENSION
                          Open Burning Fireplace - Masonry or Low Mass



• High Stack Flow Rate
   – Can be in Excess of 200 cu. ft/ min
• Free Air Flow, Uncontrolled Air Flow Paths
   – Air to Fuel Ratios above 40 - 50:1
• Relatively Low Firebox Temperatures
   – Almost Impossible to Initiate and Sustain Controlled
     Secondary Combustion
• Large Firebox Volume
   – Often > 10 Cu. Ft.
• Fireplaces are Aesthetic Devices
   –   Small Fuel Load Relative to Firebox Volume
   –   More Frequent Fueling with One or Two Fuel Pieces Added
   –   Infrequent Use Pattern (Ave. 3 -10 days per year)
   –    Typically 3 – 4 Hour Burn Cycle
                            EPA Phase II                    Open Burning Fireplace
                            Certified Controlled            - Masonry or Low Mass
                            Combustion

Stack Flow Rate             High Burn under                 Can be in Excess of 200
                            20 cu. ft/ min                  cu. ft/ min
Air Limited, Controlled     Air to Fuel Ratios              Air to Fuel Ratios
Combustion                  Typically 10 - 14:1             Typically above 40 - 50:1
Firebox Temperatures        High to Initiate and Sustain    Below Levels to Initiate
                            Controlled Secondary            and Sustain Controlled
                            Combustion                      Secondary Combustion

Firebox Volume              1 - 5 Cu. Ft.                   Often > 10 Cu. Ft.


Appliance Use and Fueling   Heating Appliances:             Aesthetic Devices:
Characteristics             Less Frequent Fueling with      Small Fuel Loads
                            Full Firebox Loads              More Frequent Fueling
                            Little or no User Interaction   Frequent User Interaction
                            Between Loads                   (Poking)

Burn Duration               Typically a 24/7 Burn Cycle     Typically a 3 to 4 Hour
                                                            Burn Cycle
Use Patterns                Frequent to Constant during     Infrequent Use
                            Heating Season                  Average in Range of 3 – 10
                                                            days per year
                    Open Burning Fireplace - Masonry or Low Mass




• Design Challenges to Obtain Particulate
  Emission Improvement in Fireplaces
  – Reduce Excess Air
  – Control Air Flow Paths
  – Increase Firebox Temperatures
  – Prevent Smoke Spillage from Front of Open
    Fireplace
  – Maintain User Expectations for Open Fire
     • Invisible Technology from Consumer’s Viewpoint
  – Minimize Incremental Cost Increase to Preserve
    Sales Opportunities.

				
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