Understanding EPA Phase I - Hydronic Boilers - PDF (69 kb)
Wood Doctor EPA Phase 1 Boilers
Wood Doctor HE10000 Gasification Boiler - EPA Phase
I
The Phase 1 orange tag means the model pollutes about 70% less than unqualified models.
Understanding EPA Phase
II - Hydronic Boilers
- PDF (67 kb)
Polar EPA Phase 2 Boilers
Wood Doctor EPA Phase 2 Boilers
Wood Doctor HE5000 140,000 Btu Boiler
- EPA Phase II
Wood Doctor HE8000 248,000 Btu Boiler
- EPA Phase II
The Phase II white tag means the model pollutes about 90% less than unqualified models
NOT ALL BOILERS LISTED IN THE EPA PHASE
II LIST ARE WOOD BOILERS!
Understanding how the tests get performed.
EPA Hydronic Boiler Tests are designed to test the emissions of the heating appliance, the
EPA Btu listed ratings are generated
from results of the controlled EPA emissions test and
may not represent the actual Btu output of the appliance.
The EPA Wood Hydronic Boiler Emission Tests are performed with fire wood of a specific type, density, moisture content and specific
amount of firewood (we currently have not been provided
the type of firewood used) for a defined eight hour period of time.
This is to set a standard to
ensure that all wood fired hydronic boilers are tested the same, with consistent, comparable
and
controllable results in regards to emissions.
The EPA test Btu rating does not represent the potential Btu output of the appliance, as this is not using cordwood or
testing the hydronic boiler or heating appliance to its fullest capacity.
Wood stoves typically have two Btu output ratings. EPA test Btu and Cord wood Btu. See the specifications of the
Osburn 2400 Wood Stove
as an example. The EPA test 40,900 Btu and cordwood Btu 100,000 rating on this stove. The smaller
the firebox the tighter the Btu between the EPA test and cord wood rating. See the specifications of the
Osburn 1100 Wood Stove
as an example. The EPA test 35,000 Btu rating and cordwood Btu 45,000 rating on this stove.
The amount of wood used for the test on the Wood Doctor HE8000 was 130 pounds of firewood. The hydronic boiler was tested over an
eight hour period. The test information we received did not indicate whether the boiler burned all the firewood in the eight hour period.
The test burn of 130 lbs of EPA test firewood created 896,000 Btu of useable heat between
160 and 180 degrees Fahrenheit.
So 896,000 Btu divided by 8 hours = 112,000 Btu / hour.
In a controlled laboratory burn, it is possible to get 8660 Btu/lb of wood fuel, no more! So 130lbs wood = 1,125,800 Btu input
and 896,000 Btu output would be a 79% efficiency rating not 76%!
Again what kind of wood was used by EPA for the test? As in order to get the EPA 76% rating
of this appliance the results indicate
the input Btu of the wood used would have to have been 1,178,947 Btu/130lbs or 9068 Btu/lb of wood.
The EPA emissions test only filled the firebox of the Wood Doctor HE8000 to less then half of its capacity based on its
13.3 cu.ft. of firebox. As even using white poplar with a weight of 2370 pounds per 128 cu.ft. of "stacked" cord of wood,
is 18.5 pounds per cubic foot would increase the wood capacity of the firebox to 240.5 pounds of firewood and if you optimally
stacked the wood in the fire box and managed to increase the density of the firewood to 100 cu.ft. of solid firewood per cord
(optimum being 80 cu.ft. of solid wood) you could possible increase the capacity to 23.7 pounds per cubic foot. So 23.7 pounds
per cubic foot times the 13.3 cubic feet of firebox = 315 pounds of firewood compared to the EPA test wood weight of 130 pounds.
This is a potential 240% difference in firebox capacity.
Ultimately we need more detailed information on the firewood used and tests actual procedure.
Previous tests in the Wood Doctor yard of the HE8000 with a starting temperature of 180 degree Fahrenheit produced a draw of
300,000 Btu for the first hour (this is because 50,000 + Btu can be stored in the water jacket of 150 gallons between the drop
in temperature from 180F and 160F)and the 248,000 Btu / hour thereafter.