![Return to Lopez Labs Home Page](../../graphics/mastlop.gif)
Test MHA-1640
March 31, 2016
Go to all tests
Repeat of 1627, all birch.
Extra test #5 of matched load series to investigate PM repeatability with cordwood
Log cabin stacking, side ignition,
63.0 lbs including 3.0 lbs kindling
16.2% moisture.
Last test of this series.
"Heavy air" day, rainy and foggy.
Intake air flow down about 5%. Compare lab notes (link below) with MHA-1628,
also a "heavy air" day, also down 5%.
Baffle supports opened up. See MHA-1625
Air slots in firebox unblocked, except for top course (25% restriction)
See MHA-1623 for other modifications.
Original test + 6 matched loads + 5 extra tests
![](MHA%20research%20heater/Data%20Summaries/COV%20cordwood%20MHA1640.JPG)
Coefficient of Variation (CV, or COV) is the standard deviation divided by the average.
25% COV means that on average a PM test number is accurate within +/- 25%
![](MHA%20research%20heater/Data%20Summaries/COV%20graph1640.GIF)
Cumulative coefficient of variation. After the first 3 tests, it looked like the COV was very tight, around 3%.
However, with more tests it settled to its realistic value, around 25%.
Compare with previous Lopez Labs crib repeatability testing, which yielded a COV of 10.2% with 4 sets of matched cribs (8 test runs)
Note
in the crib testing that the CO repeatability was much tigher, within
1.5%, although the CO value itself was about 8X higher than the
Eco-firebox.
In both cases, the efficiency was extremely tight.
Recently, MHA ran the Condar against Method M5G-3 on 3 pellets stoves (18 tests total) and achieved a COV of 3.1%
![](MHA%20research%20heater/Condar%20MHA1640.GIF) |
|
Condar summary
| |
Condar Spreadsheet
Raw Testo Data
Lab Notes![](MHA%20research%20heater/mha1640formatted.GIF)
Gas graph. CO low was 68 ppm
![](MHA%20research%20heater/mha%201640.gif)
Testo gas graph.
![](MHA%20research%20heater/DSC_2358b.JPG)
![](MHA%20research%20heater/DSC_2359b.JPG)
This page was updated on March 31, 2016
This page was created on March 31, 2016