2017 MHA Annual Meeting
Heater by AFPMA
Castable Refractory Oven Experiment
Heater by AFPMA
Multifunctional Masonry Heater
Rocket Cookstove and Heater
Finnish Contraflow for Beginner Masons
by Chris Prior
TU-2200 Top Vent
Tiileri Brick Heater Kit
and firebox floor.
gap between the firebox and the outer skin is a passageway for
enters the firebox through horizontal slots at each course.
air slots are visible. The are created by sitting the firebricks on
of white ceramic fiber create expansion joints between the firebox and
the heat exchanger.
gases will exit the firebox at the top and then downdraft through the
first heat exchange channel.
stainless tube is embedded that will act as a pressure measuring
location for the top of the firebox.
ceiling is a piece of vermiculite board
from the downdrafting heat exchange channel is visible at the bottom.
The vertical brick is a temporary support.
of the air slots.
the gases leave the downdrafting heat exchange channel, they enter the
left side of the horizontal bench.
return at the end, and will exit the right side at the top of the bench.
gases enter a vertical section of brick chimney. The transition
section, shown above, will support 8" stainless pipe.
slabs over firebox.
for stainless pipe.
the bench with soapstone slabs.
slabs are installed as bench tops.
the firebox door.
Lehmann designed the heater. He is a founding member of AFPMA, the
of France. He has developed an open source version of a handbuilt
heater calculation model, based on EN-13384.
is collaborating with MHA to build a testing lab in France and in Canada to do
verification testing to proof the calculator model.
fire with small wood.
Homsted sets up the
Condar portable dilution tunnel particulate sampler.
fire continues with a load of regular firewood. The goal is to have the
heater completely dried out for testing the next day.
test load was lit at 1:07 PM. Note that the camera shows one
earlier. This photo is at 1:40, ie 33 minutes into the test.
The heater has clay plaster, and you can see it starting to dry out
around the door.
intense fire with the Eco-labelled air
The heater was burning way too fast, and the Condar filter plugged up
at 38 minutes, highly unusual.
PM was 5.08 g/kg, or very high (for a masonry heater).
Spoiler alert: we increased the size of the wood slightly for the next
test, and the PM cam down to 0.7 g/kg.
progression in the drying of the plaster from 54 minutes earlier
Homsted pulls the final set of Condar filters for weighing.
balance for weighing the 4" glass Condar filters. Set on a solid
resolves to 0.0001 gram
#2, the following day.
Myren weighing kindling for fuel load.
runs an EPA accredited testing lab in Colville, WA and has more than 30
years experience in the field
the first test, the firebox was still fairly hot from curing late
the day before, which also contributed to the over-amping. It was a
valuable demo. Comparing predicted values from the calculator,
indicated that the heater needed more heat exchange. Ie.., stack
temperature was too high..
This resulted in the burn rate going high enough that there was not
sufficient air anymore, resulting in high emissions.
Paquin helps Ben Myren with the wood.
weight is written on each piece, and the geometry of the fuel pile is
computer on the right runs the Testo 330-2 gas analyzer.
other computer is from the MHA
in Shawville Quebec
down 5 channel version of the pressure sensing setups that we have at
and AFPMA labs.
SDP-610 digital sensors are very accurate and repeatable with
a resolution of 0.1 pa.
are part of our collaborative project
to verify a software model for one-off handbuilt heaters.
lab computer. The white dongle at the back is an IOWarrior
It provides the digital interface between the sensors and the
computer's USB port.
Note there are only 4 wires, yet up to 128 separate channels of
pressure readings can be connected via the
I2C digital communications protocol. The data logging is done via DAQFactory Pro.
the load for the second test run. Larger fuel pieces were used,
compared to run #1.
load was 21.9 kg at 16% moisture.
and piece number (position in the firebox stack) is marked on each
piece and recorded.
sits in a gap between the two larger pieces.
10 minutes, only white steam is visible from the stack.
Myren made a drawing explaining how fire box volume is calculated for
EPA certification testing, to determine the fuel load.
load was 21.9 kg plus 0.8 kg kindling for a total of 22.7 kg.
the new ASTM cordwood method that will be used for EPA testing for
woodstoves, the load for a firebox this size should be 25.0 - 30.4 kg.
Labjack T7 Pro
can handle up to 40 channels of thermocouples or other sensors, and is
interfaced with DAQFactory Pro at the MHA and AFPMA labs.
13 minutes, the stack temperature is high enough that there is no steam
for this run was 0.7 g/kg, which is cleaner than the average of 6
common pellet stoves that we have measured with the Condar.
of portable testing setup showning pressure and temperature connections.
pieces with individual weights marked (in lbs).
fuel load for third test run, Friday afternoon (pizza party day).
nearing the end, as the pizza party is gearing up in the background.
of many reloads.
had the chance to do a bit of destructive testing ;-) to see how the
single thickness firebox would stand up.
2006 Photo Report
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2002 Photo Report
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2000 Photo Report
1999 Photo Report
1998 Photo Report
1997 Photo Report
page was last updated on February 2, 2018
This page was created on April 18, 2017