February 2015
Test Report
RioLite™ HomeStove™ with Wood Fuel
Air Pollutant Emissions and Fuel Efficiency
Prepared by:
James J. Jetter, P.E.
Seth Ebersviller, Ph.D.
U.S. Environmental Protection Agency
Cookstove Testing Facility operated by:
Craig Williams
Jerroll Faircloth
ARCADIS ARCADIS U.S., Inc.
A contractor to the U.S. Environmental Protection Agency
Research Triangle Park, North Carolina, USA
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Notice
The U.S. Environmental Protection Agency (EPA), through its Office of Research and
Development, has financially supported the testing described here. This document has been
reviewed by the Agency. Mention of trade names or commercial products does not constitute
endorsement or recommendation by the EPA for use.
Prepared by:
James J. Jetter, P.E., Principal Investigator
Seth Ebersviller, Ph.D., Post-Doctoral Fellow
Air Pollution Prevention and Control Division
National Risk Management Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
i
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Executive Summary
The U.S. Environmental Protection Agency's (EPA's) cookstove testing program was first developed to
assist the EPA-led Partnership for Clean Indoor Air (1) and is now part of the U.S. Government's
commitment to the Global Alliance for Clean Cookstoves (the Alliance) (2). Goals of the testing program
are to:
1. Support the development of testing protocols and standards for cookstoves through ISO TC
(Technical Committee) 285: Clean Cookstoves and Clean Cooking Solutions (3).
2. Support the development of international Regional Testing and Knowledge Centers (many
sponsored by the Alliance) for scientifically evaluating and certifying cookstoves to international
standards (4).
3. Provide an independent source of data to Alliance partners.
This work supports EPA's mission to protect human health and the environment. Household air
pollution, mainly from solid-fuel cookstoves in the developing world, is estimated to cause
approximately 4 million premature deaths per year (5), and emissions of black carbon and other
pollutants from cookstoves affect regional and global climate (6). An Alliance-coordinated multi-
national multi-disciplinary approach, including the development of standards and testing, is designed to
improve global health and the environment through clean cooking solutions (7).
This report provides testing results for a cookstove system consisting of the stove, cooking pot, fuel, and
operating procedure. A detailed description of the system is provided in the body of the report. During
testing, the stove was operated as intended by the manufacturer. Actual performance of a cookstove
used in the field may vary if the system is different (e.g., a different fuel is used) or is not operated as
intended.
The cookstove system was tested using the Water Boiling Test (WBT) Version 4.2.3 (8) and following the
ISO (International Organization for Standardization) IWA (International Workshop Agreement) 11-2012,
Guidelines for Evaluating Cookstove Performance (9) (10), unanimously affirmed by more than 90
stakeholders at the ISO International Workshop on Cookstoves on February 28-29, 2012 in The Hague,
Netherlands. IWA Guidelines are being used while further development of testing protocols and
standards is underway through ISO Technical Committee 285 (3). For measuring air pollutant emissions,
the "total capture" method (also known as the "hood" method) was used, as described on Pages 60-61
of the WBT protocol (8). The WBT protocol specifies that the stove is tested at high power (cold- and
hot-start phases) and low power (simmer phase). The cold-start phase begins with the stove at ambient
temperature, and the hot-start phase begins with the stove at operating temperature. During both
phases, the stove is operated at high power to heat water in the pot from ambient to boiling
temperature. During the simmer phase, the stove is operated at low power to maintain the target
water temperature at 3°C below the boiling point. Fuel burning rates determine the power levels.
During testing, variation in fuel burning rates between test replications is minimized. Actual
performance of a cookstove used in the field may vary if the stove is operated at different fuel burning
rates and hence at different power levels.
ii
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Test results summarized on Page iv were obtained in accordance with ISO IWA 11:2012 guidelines for
rating cookstoves on tiers of performance for four important indicators: [1] Efficiency/fuel use, [2] Total
Emissions, [3] Indoor Emissions, and [4] Safety. Tier ratings range from 0 (baseline) to 4 (best). Tier 0
represents the performance of typical traditional open three-stone fires used for cooking, and Tier 4
represents aspirational goals for solid-fuel cookstoves. Efficiency/fuel use, total emissions, and indoor
emissions are tested at high- and low-power operating conditions, and sub-tier values and ratings are
reported for the two power levels, while the overall rating is the lowest sub-tier rating, as specified in
the IWA. Sub-tier values and ratings for many different stove types are compared in Figures 3 & 5-8 of
this report. Following are brief descriptions of performance indicators specified in the IWA.
Efficiency/fuel use is an important indicator, especially for cookstoves used in areas where fuel is scarce
or expensive or where forest degradation is an issue due to unsustainable harvesting of wood for fuel.
Greater fuel efficiency is desirable, but increased efficiency does not always correlate with reduced
emissions of air pollutants. Efficiency/fuel use tier levels are based on thermal efficiency at high power
and specific energy use at low power, per the IWA.
Total emissions of air pollutants from cookstoves have potential impact on human health and climate
change. CO (carbon monoxide) and PM2.5 (fine particulate matter) are indicator pollutants specified in
IWA 11:2012, and emissions of additional pollutants are quantified in this report, including gaseous
pollutants C02 (carbon dioxide), THC (total hydrocarbons), CH4 (methane), and NOx (nitrogen oxides), as
well as particulate OC (organic carbon), EC (elemental carbon), and BC (black carbon). Total emission
tier levels are based on the mass of pollutant emitted per useful energy delivered at high power and the
specific emission rate at low-power, per the IWA.
Indoor emissions have a potential direct impact on human health, and emissions may be reduced by
stoves with cleaner combustion and/or with chimneys (flues). Stoves without chimneys are tested for
total emissions into the indoor space, and stoves with chimneys are tested for fugitive emissions from
the stove. Indoor emissions tier levels are based on emission rates, per the IWA.
Safety is also an important indicator included in IWA 11:2012 for evaluation of stoves for protection
from risk of burns and other injuries, but safety is not evaluated in this report.
Cooking power is not an IWA performance indicator, but it is reported in the summary because it can be
important for meeting user needs.
Fuel burning rates are reported to define the test conditions.
IWA tier ratings are based on the performance of the stove system operated as intended with low-
moisture fuel. Additional test results are provided in this report for energy efficiency, fuel use, and air
pollutant emissions for both low- and high-moisture fuel. Discussion of results, observations, and
quality assurance are also included in the report.
iii
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Stove Manufacturer
& Model
BioLite™ New York, NY, USA
HomeStove™ H504T3-01
Testing Center
EPA-Research Triangle Park, North Carolina, USA
Test Protocol
WBT Version 4.2.3, EPA Rev. 4 [see Reference (8)]
Fuel Used
Red Oak, average moisture content 8.4%, dimensions: 2 x 2 x 36 cm
Pot Used
Standard flat-bottom 7L pot with 5L of water, with pot skirt
Test results were obtained in accordance with ISO (International Organization for
Standardization) IWA (International Workshop Agreement) 11:2012. See previous page for
brief description.
Metric
Value
Unit
Sub-Tier
Efficiency / Fuel Use
Tier
2
High Power Thermal Efficiency
33
%
2
Low Power Specific Energy Use
0.027
MJ / (min L)
3
Total Emissions
Tier
3
High Power CO
1.0
g / MJdelivered
4
Low Power CO
0.07
g/ (min L)
4
High Power PM2.5
155
mg / MJdelivered
3
Low Power PM2.5
1.4
mg / (min L)
3
Indoor Emissions
Tier
2
High Power CO
0.07
g/ min
4
Low Power CO
0.28
g/ min
4
High Power PM2.5
12.3
mg / min
2
Low Power PM2.5
6.0
mg / min
3
Tiers 0 4 (best)
Value
Unit
Cooking Power (average of Cold Start and Hot Start phases)
1313
W
Fuel burning rate (average for Cold Start, based on equivalent dry fuel consumed)
11.7
g/ min
Fuel burning rate (average for Hot Start, based on equivalent dry fuel consumed)
14.3
g/ min
Fuel burning rate (average for Simmer, based on equivalent dry fuel consumed)
6.4
g/ min
IV
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Acronyms and Abbreviations
Alliance Global Alliance for Clean Cookstoves
ASTM American Society for Testing and Materials (now known as ASTM International)
BC black carbon
C carbon
C3H8 propane
CH4 methane
cm centimeter
CO carbon monoxide
C02 carbon dioxide
CPC condensation particle counter
EC elemental carbon
EPA Environmental Protection Agency
g gram
HEPA high-efficiency particulate air
ISO International Organization for Standardization
IWA International Workshop Agreement
kg kilogram
kJ kilojoule
L liter
MCE modified combustion efficiency
Met Lab Metrology Laboratory
mg milligram
min minute
MJ megajoule
MJdeiivered megajoule of useful energy delivered
mm millimeter
n.a. not applicable
NIOSH National Institute for Occupational Safety and Health
NOx nitrogen oxides
OC organic carbon
PM2.5 particulate matter with an aerodynamic diameter < 2.5 micrometers
RTP Research Triangle Park
SD standard deviation
SMPS Scanning Mobility Particle Sizer
SOP Standard Operating Procedure
TC Technical Committee
TC total carbon
THC total hydrocarbon
W Watt
WBT Water Boiling Test
v
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Contents
Notice i
Executive Summary ii
Acronyms and Abbreviations v
Figures vi
Tables vii
Cookstove Testing Program 1
Description of Cookstove System Tested 1
Test Protocol 3
Test Results for Low-Moisture Fuel 3
Test Results for High-Moisture Fuel 13
Discussion of Results and Observations 20
Quality Assurance/Quality Control 21
Acknowledgements 23
References 24
Figures
Figure 1. BioLite HomeStove with pot skirt 2
Figure 2. Cooking power versus fire power during high-power 5
Figure 3. Specific energy consumption during low-power versus thermal efficiency during high-power... 5
Figure 4. Modified combustion efficiency, low-power versus high-power 6
Figure 5. CO versus PM25 emissions per useful energy delivered to the cooking pot during high-power.. 6
Figure 6. CO versus PM25 emissions per liter of water simmered per minute during low-power 7
Figure 7. CO versus PM25 indoor emission rates during high-power 7
Figure 8. CO versus PM25 indoor emission rates during low-power 8
vi
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Tables
Table 1. Low-moisture fuel, high-power cold-start - WBT, PM2.5, and gaseous pollutant parameters 9
Table 2. Low-moisture fuel, high-power hot-start - WBT, PM2.5, and gaseous pollutant parameters 10
Table 3. Low-moisture fuel, low-power (30-min simmer) - WBT and pollutant emission parameters 11
Table 4. Low-moisture fuel - emissions of OC (organic carbon) and EC (elemental carbon) in PM2.5 12
Table 5. Low-moisture fuel - PM2.5 mass fractions of organic carbon to total carbon (OC/TC) and
elemental carbon to total carbon (EC/TC) 13
Table 6. Low-moisture fuel - emissions of BC (black carbon) measured with aethalometer 13
Table 7. High-moisture fuel, high-power cold-start - WBT, PM2.5, and gaseous pollutant parameters.... 14
Table 8. High-moisture fuel, high-power hot-start - WBT, PM2.5, and gaseous pollutant parameters 15
Table 9. High-moisture fuel, low-power (30-min simmer) - WBT and pollutant emission parameters.... 16
Table 10. High-moisture fuel - emissions of PM2.5 OC (organic carbon) and EC (elemental carbon) 17
Table 11. High-moisture fuel - PM2.5 mass fractions of organic carbon to total carbon (OC/TC) and
elemental carbon to total carbon (EC/TC) 17
Table 12. High-moisture fuel - emissions of BC (black carbon) measured with aethalometer 18
Table 13. Comparison of low- and high-moisture fuel - WBT, PM2.5 and gaseous pollutants 19
Table 14. Comparison of low- and high-moisture fuel - PM2.5 organic and elemental carbon 20
Table 15. Comparison of low- and high-moisture fuel - emissions of black carbon (aethalometer) 20
Table 16. Carbon balance, percent difference based on fuel carbon (see Appendix) 22
Table 17. Measurement quality objectives for critical measurements 23
vii
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Cookstove Testing Program
The U.S. Environmental Protection Agency's (EPA's) cookstove testing program was first developed to
assist the EPA-led Partnership for Clean Indoor Air (1) and is now part of the U.S. Government's
commitment to the Global Alliance for Clean Cookstoves (the Alliance) (2). Goals of the testing program
are to:
1. Support the development of testing protocols and standards for cookstoves through ISO TC
(Technical Committee) 285: Clean Cookstoves and Clean Cooking Solutions (3).
2. Support the development of international Regional Testing and Knowledge Centers (many
sponsored by the Alliance) for scientifically evaluating and certifying cookstoves to international
standards (4).
3. Provide an independent source of data to Alliance partners.
This work supports EPA's mission to protect human health and the environment. Household air
pollution, mainly from solid-fuel cookstoves in the developing world, is estimated to cause
approximately 4 million premature deaths per year (5), and emissions of black carbon and other
pollutants from cookstoves affect regional and global climate (6). An Alliance-coordinated multi-
national multi-disciplinary approach, including the development of standards and testing, is designed to
improve global health and the environment through clean cooking solutions (7).
Description of Cookstove System Tested
A cookstove system consists of the stove, cooking pot, fuel, and operating procedure. The default
operating procedure used for testing is the written instructions provided by the manufacturer, or
operation as intended by the manufacturer. Actual performance of a cookstove used in the field may
vary if the system is not operated as intended.
Development and dissemination. The HomeStove, shown in Figure 1, was developed by BioLite, New
York, NY, USA, and is manufactured in China. The stove is designed for dissemination in the developing
world.
Type of stove. The HomeStove is a forced-draft (fan) type of stove, and it may also be classified as a
rocket-type stove. If the fan fails, then the stove will operate as a natural-draft rocket stove, albeit at a
lower level of performance. A thermoelectric generator, powered by the heat from combustion,
provides electrical power to the fan and may be used as an auxiliary source of electricity for low-power
applications such as charging a mobile device (e.g., cellular phone) or operating a light emitting diode
(LED). The stove is designed to burn wood fuel sticks that are manually fed into an opening in the lower
front of the stove. The fan operates automatically with no user controls and no rechargeable battery.
Construction materials. The base, lower combustion chamber, and top are constructed of cast iron.
The outer shell and upper combustion chamber are stainless steel. A molded polymer housing located
on the back side of the stove contains the fan and electronics. Total weight of the stove is 8.3 kg.
1
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Dimensions.
Height (not including pot skirt): 30.4 cm
Height (including pot skirt): 38,1 cm
Outside diameter of base: 27.5 cm
Outside diameter of top: 27.5 cm
Fuel/air inlet opening: 12 cm wide x 9.5 cm high
Inside diameter of upper combustion chamber: 7.7 cm
Figure 1. BioLite HomeStove with pot skirt
Accessories. An adjustable pot skirt was supplied with the stove, and the stove was tested with the
skirt. Pot skirts tend to improve performance by enhancing heat transfer from the combustion gases to
the cooking pot. Performance may vary if the stove is used without the skirt.
Cooking pot. A default standard flat-bottomed pot was used for the tests. This pot has a weight of
approximately 815 grams. Full capacity is approximately 7 liters, and the pot is used with 5 liters of
water for the tests. Material is stainless steel. Outside diameter of the rolled edge at the top of the pot
is 257 mm, and inside diameter of the pot at the top is 244 mm. Outside diameter at the bottom is 243
mm. Height (not including handles) is 162 mm. The pot was obtained from the CICCI company
(Copenhagen, Denmark) that provides supplies for emergency relief and development projects around
the world. Performance may vary if the stove is used with a different cooking pot.
Fuel. A hardwood, Red Oak (Quercus rubra), was obtained from a local supplier. Bark was removed,
and the wood was saw-cut to dimensions of 2 cm x 2 cm x 36 cm long for low-moisture fuel and
dimensions of 1 cm x 2 cm x 36 cm long for high-moisture fuel. Wood was air dried, and high-moisture
fuel was preserved in air-sealed containers in a freezer. Moisture content is reported on a wet basis in
Tables 1-3 for low-moisture fuel and in Tables 7-9 for high-moisture fuel. Performance may vary if the
stove is used with a different type of fuel.
Operating procedure. At the time of testing, a manual was not available for the stove, but
manufacturer representatives demonstrated its operation for the EPA testing team. During tests,
fuelwood sticks were manually fed into the stove at a consistent burning rate, as reported in the results
section.
Cost. The manufacturer declined to share this information.
Quantity disseminated. The manufacturer declined to share this information.
2
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Lifetime. Expected typical lifetime is five years, according to the manufacturer. In the future, a
durability testing protocol may be developed through ISO TC 285, and durability testing may provide
more comparable and quantitative results than estimated lifetime.
Test Protocol
The cookstove system was tested using the Water Boiling Test (WBT) Version 4.2.3 (8) and following the
ISO International Workshop Agreement Guidelines for Evaluating Cookstove Performance (9) (10).
Further development of testing protocols and standards is underway through ISO Technical Committee
285 (3). For measuring air pollutant emissions, the "total capture" method (also known as the "hood"
method) was used, as described on Pages 60-61 of the WBT protocol (8). Emissions were captured in a
fume hood and were drawn under negative pressure through a primary dilution tunnel and then
through a secondary tunnel with additional HEPA-filtered dilution air. Gaseous air pollutants were
sampled from the primary dilution tunnel, and particulates were sampled from the secondary tunnel.
The WBT protocol specifies that the stove is tested at high power (cold- and hot-start phases) and low
power (simmer phase). The cold-start phase begins with the stove at ambient temperature, and the
hot-start phase begins with the stove at operating temperature. During both phases, the stove is
operated at high power to heat water in the pot from ambient to boiling temperature. During the
simmer phase, the stove is operated at low power to maintain the target water temperature at 3°C
below the boiling point. Fuel burning rates determine the power levels. During testing, variation in fuel
burning rates between test replications is minimized. Actual performance of a cookstove used in the
field may vary if the stove is operated at different fuel burning rates and hence at different power levels.
Test Results for Low-Moisture Fuel
A summary of results for low-moisture fuel is presented in accordance with ISO IWA 11:2012 (9) on Page
ii of this report. IWA tier ratings are based on the performance of the stove system operated as
intended with low-moisture fuel.
BioLite HomeStove test results are compared with previously published results (11) in Figures 2-8. Key
indicators of performance shown in the figures are described in Jetter et al. 2012 (11). Error bars on the
data points for the HomeStove indicate ± one standard deviation. For reference, data points for the 3-
stone fire are indicated by red-colored X markers. Two data points are shown on each graph for a
carefully-tended and a minimally-tended 3-stone fire. The carefully-tended fire performed better than
the minimally-tended fire in all measures (11). Data points (blue diamonds indicated by the letter "P")
are indicated for the Philips HD4012 stove for comparison, because it is a well-known and relatively
high-performing forced-draft stove. Data points for other stoves with previously published results are
not identified in Figures 2-8, but stoves are identified in the journal article (11). All data shown in the
figures are for stoves tested with low-moisture fuels, as described in the published results (11).
Figure 2 shows cooking power versus fire power (in units of measurement of Watts) during high-power
(average of cold-start and hot-start phases of the WBT). Cooking power is the rate of useful energy
delivered to the contents of the cooking pot, while fire power is the rate of fuel energy used. Adequate
3
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cooking power is important for user acceptability, and cooking power is correlated with "time-to-boil"
(11). The ratio of cooking power to fire power is thermal efficiency - shown in Figure 3.
Figure 3 shows specific energy use during low-power (simmer phase of the WBT) versus thermal
efficiency during high-power (average of cold-start and hot-start phases of the WBT). These metrics are
used to determine IWA Tier ratings, and the IWA Sub-Tiers are indicated in the figure.
Figure 4 shows low-power versus high-power MCE (modified combustion efficiency). MCE is defined as
[C02/(C02 + CO)] on a molar basis and is considered a reasonable proxy for true combustion efficiency.
MCE is not used to determine IWA Tier ratings, but stoves with higher MCEs tend to have lower
emissions of air pollutants. Best performance is indicated in the upper right corner of the graph.
Figure 5 shows CO (carbon monoxide) versus PM25 (particulate matter with an aerodynamic diameter <
2.5 micrometers) emissions per useful energy delivered to the water in the cooking pot during high-
power phases of the WBT. Pollutant emissions per useful energy delivered and thermal efficiency are
key IWA metrics because they are based on the fundamental desired output - cooking energy - that
enables valid comparisons between all stoves and fuels.
Figure 6 shows CO versus PM25 emissions per minute per liter of water simmered during the low-power
phase of the WBT. Useful cooking energy is not accurately measured during the low-power test phase
of the WBT (11), therefore the specific emission rate is used as the metric, per the IWA.
Figure 7 shows CO versus PM2 5 indoor emission rates during high-power phases of the WBT.
Figure 8 shows CO versus PM2 5 indoor emission rates during the low-power phase of the WBT.
Tabulated data for the BioLite HomeStove with low-moisture fuel, including data for test replicates, are
shown in Tables 1-3. The tables include data for parameters of the Water Boiling Test (8) and of
emissions of PM25 and gaseous air pollutants, as described in Jetter et al. 2012 (11). Test Numbers
shown in the column headings may not be sequential, because tests were rejected if quality assurance
requirements were not met (see Quality Assurance/Quality Control section below).
4
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A*P
¦
~
~
1
~
A
X
¦ ¦
~ ~
X
¦
¦
~
X
3-stone fire
¦
~
Charcoal stove
Forced-draft stove
A
0
Natural-draft stove
Liquid-fuel stove
2,000 4,000 6,000
Fire Power (W)
8,000
10,000
12,000
BioLite HomeStove
Error bars:
± one standard
deviation
"P" indicates Philips HD4012
forced-draft stove
Figure 2. Cooking power versus fire power during high-power
5%
X 3-stone fire
¦ Charcoal stove
~ Force d-d raft stove
A Natural-draft stove
O Liquid-fuel stove
15%
25%
35%
45%
55%
Sub-Tier 0
Sub-Tier 1
Sub-Tier 2
Sub-Tier 3 Sub-Tier 4 (best)
Thermal Efficiency, High-Power
^ BioLite HomeStove
Error bars:
± one standard
deviation
"P" indicates Philips HD4012
forced-draft stove
Figure 3. Specific energy consumption during low-power versus thermal efficiency during high-power
5
-------
o
CL
-Q
E
o
u
¦a
"D
O
100%
95%
90%
85%
80%
A A
P o*
A A
x ~
X
X 3-stone fire
¦ Charcoal stove
~ Forced-draft stove
A Natural-draft stove
O Liquid-fuel stove
80%
85% 90% 95%
Modified Combustion Efficiency, High-Power
100%
^ BioLite HomeStove
Error bars:
± one standard
deviation
"P" indicates Philips HD4012
forced-draft stove
Figure 4. Modified combustion efficiency, low-power versus high-power
100
1
0.5
10
~
~Pa
1
~ A"
100
1,000
PM2.5 Emission, High-Power (mg/MJde|ivered)
X
3-stone fire
¦
Charcoal stove
~
Forced-draft stove
~
Natural-draft stove
o
Liquid-fuel stove
10,000
Sub-Tier 4 (best)
Sub-Tier 3
2
1
Sub-Tier 0
^ BioLite HomeStove
Error bars:
± one standard
deviation
"P" indicates Philips HD4012
forced-draft stove
Figure 5. CO versus PM2.s emissions per useful energy delivered to water in the cooking pot during high-
power
6
-------
£
cy
I—
Q)
g
o
Q_
£
UJ
o
U
1.0
0.1
0.01
0
~ X
~ p
I ^
~
X
~
10
Sub-Tier 0
ZD
X 3-stone fire
¦ Charcoal stove
~ Forced-draft stove
A Natural-draft stove
O Liquid-fuel stove
100
BioLite HomeStove
Error bars:
± one standard
deviation
"P" indicates Philips HD4012
forced-draft stove
PM2.5 Emission, Low-Power (mg/min/L)
Figure 6. CO versus PM2.s emissions per liter of water simmered per minute during low-power
~
X 3-stone fire
¦ Charcoal stove
o
~ Forced-draft stove
A Natural-draft stove
O Liquid-fuel stove
10
100
1,000
4 (best)
Sub-Tier 3
2
1
Sub-Tier 0
PM2i5 Indoor Emission Rate, High-Power (mg/min)
Figure 7. CO versus PM2.s indoor emission rates during high-power
BioLite HomeStove
Error bars:
± one standard
deviation
"P" indicates Philips HD4012
forced-draft stove
7
-------
10 T
o
-------
Table 1. Low-moisture fuel, high-power cold-start - WBT, PM2.5, and gaseous pollutant parameters
Parameter
Units
Average
SD
Test 21
Test 3
Test 4
Fuel moisture (wet basis)
%
8.3
1.02
7.2
8.8
9.0
Fuel consumed (raw)
g
488.9
5.3
484.5
494.8
487.3
Equivalent dry fuel consumed
g
354.1
25.4
375.1
361.4
325.8
Time to boil 5 liters of water, 25 to 100°C
min
28.74
2.0
28.96
30.57
26.69
Thermal efficiency
%
31.0
1.7
29.9
30.1
33.0
Fuel burning rate
g/min
11.7
0.5
12.3
11.3
11.7
Temperature-corrected specific fuel consumption
g/liter
69.7
5.0
73.9
71.2
64.2
Temperature-corrected specific energy use
kJ/l iter
1277
92
1353
1304
1175
Fire power
W
3582
160
3753
3437
3556
Cooking power
W
1110
71
1124
1033
1174
Modified combustion efficiency
%
99.4
0.1
99.3
99.4
99.5
PM2.5 temperature-corrected total mass
mg
264.0
42.8
245.9
312.9
233.3
mass per effective volume of water boiled
mg/liter
54.6
8.9
51.0
64.7
48.1
mass per fuel mass (raw)
mg/kg
566.6
85.6
534.5
663.6
501.7
mass per equivalent dry fuel mass
mg/kg
783.1
112.8
690.3
908.6
750.3
mass per fuel energy
mg/MJ
42.8
6.2
37.7
49.6
41.0
mass per useful energy delivered (to water in pot)
mg/MJ
138.3
23.1
125.9
165.0
124.1
mass per time
mg/hour
549.3
56.5
509.4
614.0
524.5
CO temperature-corrected total mass
g
2.20
0.29
2.53
2.08
1.98
mass per effective volume of water boiled
g/liter
0.45
0.06
0.52
0.43
0.41
mass per fuel mass (raw)
g/kg
4.72
0.68
5.50
4.40
4.26
mass per equivalent dry fuel mass
g/kg
6.50
0.55
7.10
6.03
6.37
mass per fuel energy
g/MJ
0.36
0.03
0.39
0.33
0.35
mass per useful energy delivered (to water in pot)
g/MJ
1.15
0.13
1.30
1.10
1.05
mass per time
g/hour
4.59
0.59
5.24
4.08
4.46
C02 temperature-corrected total mass
g
565
12
574
551
568
mass per effective volume of water boiled
g/liter
117
3
119
114
117
mass per fuel mass (raw)
g/kg
1,213
40
1,249
1,169
1,222
mass per equivalent dry fuel mass
g/kg
1,680
127
1,613
1,601
1,827
mass per fuel energy
g/MJ
92
7
88
87
100
mass per useful energy delivered (to water in pot)
g/MJ
296
6
294
291
302
mass per time
g/hour
1,183
98
1,190
1,082
1,277
THC (as CsHs) temperature-corrected total mass
g
0.25
0.02
0.24
0.24
0.27
mass per effective volume of water boiled
g/liter
0.05
0.00
0.05
0.05
0.06
mass per fuel mass (raw)
g/kg
0.54
0.04
0.53
0.51
0.59
mass per equivalent dry fuel mass
g/kg
0.75
0.11
0.68
0.70
0.88
mass per fuel energy
g/MJ
0.04
0.01
0.04
0.04
0.05
mass per useful energy delivered (to water in pot)
g/MJ
0.13
0.01
0.12
0.13
0.15
mass per time
g/hour
0.53
0.07
0.50
0.48
0.61
CH4 temperature-corrected total mass
g
0.06
0.01
0.05
0.06
0.05
mass per effective volume of water boiled
g/liter
0.01
0.00
0.01
0.01
0.01
mass per fuel mass (raw)
g/kg
0.12
0.02
0.10
0.14
0.12
mass per equivalent dry fuel mass
g/kg
0.17
0.03
0.13
0.19
0.18
mass per fuel energy
g/MJ
0.01
0.00
0.01
0.01
0.01
mass per useful energy delivered (to water in pot)
g/MJ
0.03
0.00
0.02
0.03
0.03
mass per time
g/hour
0.12
0.02
0.10
0.13
0.12
NOx temperature-corrected total mass
g
0.24
0.00
0.24
0.24
0.23
mass per effective volume of water boiled
g/liter
0.05
0.00
0.05
0.05
0.05
mass per fuel mass (raw)
g/kg
0.51
0.01
0.52
0.51
0.50
mass per equivalent dry fuel mass
g/kg
0.71
0.04
0.67
0.69
0.75
mass per fuel energy
g/MJ
0.04
0.00
0.04
0.04
0.04
mass per useful energy delivered (to water in pot)
g/MJ
0.12
0.00
0.12
0.13
0.12
mass per time
g/hour
0.50
0.03
0.50
0.47
0.52
1 Test 1 rejected and not included due to improper ignition of fuel
9
-------
Table 2. Low-moisture fuel, high-power hot-start - WBT, PM2.5, and gaseous pollutant parameters
Parameter
Units
Average
SD
Test 1
Test 2
Test 3
Test 4
Fuel moisture (wet basis)
%
8.5
0.87
8.8
7.2
8.8
9.0
Fuel consumed (raw)
g
436.5
13.2
426.5
449.0
423.9
446.7
Equivalent dry fuel consumed
g
311.7
28.4
311.0
349.4
280.6
305.9
Time to boil 5 liters of water, 25 to 100°C
min
21.03
2.7
21.56
24.46
17.93
20.18
Thermal efficiency
%
34.7
2.3
33.9
31.9
37.3
35.7
Fuel burning rate
g/min
14.3
0.6
13.8
13.7
15.0
14.6
Temperature-corrected specific fuel consumption
g/liter
61.9
5.9
62.1
69.5
55.2
60.9
Temperature-corrected specific energy use
kJ/l iter
1134
108
1137
1273
1010
1116
Fire power
W
4355
186
4222
4181
4574
4442
Cooking power
W
1515
165
1431
1336
1707
1586
Modified combustion efficiency
%
99.5
0.1
99.4
99.5
99.7
99.5
PM2.5 temperature-corrected total mass
mg
327.9
92.7
277.7
462.9
258.9
312.2
mass per effective volume of water boiled
mg/liter
67.9
19.4
57.8
96.1
53.2
64.7
mass per fuel mass (raw)
mg/kg
779.8
200.2
678.8
1075.0
637.7
727.8
mass per equivalent dry fuel mass
mg/kg
1084.6
205.7
930.8
1381.5
963.5
1062.7
mass per fuel energy
mg/MJ
59.2
11.2
50.8
75.5
52.6
58.0
mass per useful energy delivered (to water in pot)
mg/MJ
172.4
43.4
150.0
236.2
141.0
162.6
mass per time
mg/hour
925.8
153.9
772.6
1135.7
866.6
928.2
CO temperature-corrected total mass
g
1.55
0.40
1.88
1.63
0.97
1.72
mass per effective volume of water boiled
g/liter
0.32
0.08
0.39
0.34
0.20
0.36
mass per fuel mass (raw)
g/kg
3.70
0.93
4.61
3.79
2.40
4.01
mass per equivalent dry fuel mass
g/kg
5.16
1.19
6.31
4.87
3.63
5.85
mass per fuel energy
g/MJ
0.28
0.06
0.34
0.27
0.20
0.32
mass per useful energy delivered (to water in pot)
g/MJ
0.82
0.21
1.02
0.83
0.53
0.89
mass per time
g/hour
4.40
0.94
5.24
4.00
3.26
5.11
C02 temperature-corrected total mass
g
488
36
482
503
442
526
mass per effective volume of water boiled
g/liter
101
8
100
104
91
109
mass per fuel mass (raw)
g/kg
1,165
57
1,177
1,168
1,088
1,225
mass per equivalent dry fuel mass
g/kg
1,637
118
1,614
1,501
1,645
1,789
mass per fuel energy
g/MJ
89
6
88
82
90
98
mass per useful energy delivered (to water in pot)
g/MJ
258
14
260
257
241
274
mass per time
g/hour
1,404
146
1,340
1,234
1,479
1,563
THC (as CsHs) temperature-corrected total mass
g
0.22
0.03
no1
0.19
0.24
0.24
mass per effective volume of water boiled
g/liter
0.05
0.01
no1
0.04
0.05
0.05
mass per fuel mass (raw)
g/kg
0.52
0.08
no1
0.44
0.58
0.56
mass per equivalent dry fuel mass
g/kg
0.75
0.17
no1
0.56
0.88
0.81
mass per fuel energy
g/MJ
0.04
0.01
no1
0.03
0.05
0.04
mass per useful energy delivered (to water in pot)
g/MJ
0.12
0.02
no1
0.10
0.13
0.12
mass per time
g/hour
0.65
0.17
no1
0.46
0.79
0.71
CH4 temperature-corrected total mass
g
0.03
0.01
0.04
0.03
0.02
0.03
mass per effective volume of water boiled
g/liter
0.01
0.00
0.01
0.01
0.00
0.01
mass per fuel mass (raw)
g/kg
0.07
0.03
0.10
0.06
0.04
0.07
mass per equivalent dry fuel mass
g/kg
0.10
0.03
0.14
0.08
0.06
0.11
mass per fuel energy
g/MJ
0.01
0.00
0.01
0.00
0.00
0.01
mass per useful energy delivered (to water in pot)
g/MJ
0.02
0.01
0.02
0.01
0.01
0.02
mass per time
g/hour
0.08
0.03
0.12
0.07
0.06
0.09
NOx temperature-corrected total mass
g
0.21
0.02
0.19
0.23
0.20
0.22
mass per effective volume of water boiled
g/liter
0.04
0.00
0.04
0.05
0.04
0.05
mass per fuel mass (raw)
g/kg
0.50
0.03
0.47
0.54
0.48
0.52
mass per equivalent dry fuel mass
g/kg
0.70
0.05
0.64
0.69
0.73
0.76
mass per fuel energy
g/MJ
0.04
0.00
0.03
0.04
0.04
0.04
mass per useful energy delivered (to water in pot)
g/MJ
0.11
0.01
0.10
0.12
0.11
0.12
mass per time
g/hour
0.60
0.06
0.53
0.57
0.65
0.66
1 THC data rejected and not included because it did not meet QA acceptance criteria per Table 17.
10
-------
Table 3. Low-moisture fuel, low-power (30-min simmer) - WBT and pollutant emission parameters
Parameter
Units
Average
SD
Test 1
Test 2
Test 3
Test 4
Fuel moisture (wet basis)
%
8.5
0.87
8.8
7.2
8.8
9.0
Fuel consumed (raw)
g
193.3
21.1
193.7
222.3
183.7
173.4
Equivalent dry fuel consumed
g
193.2
11.4
184.8
207.5
197.2
183.4
Fuel burning rate
g/min
6.4
0.4
6.2
6.9
6.6
6.1
Specific fuel consumption
g/liter
44.9
2.8
43.2
48.4
45.7
42.2
Specific energy use
kJ/liter
822
51
791
887
837
773
Fire power
W
1966
114
1880
2105
2015
1866
Modified combustion efficiency
%
96.1
0.2
95.7
96.3
96.3
96.1
PM2.5 total mass
mg
181.1
42.9
156.9
160.0
162.2
245.3
mass per volume of water remaining
mg/liter
42.0
9.6
36.7
37.3
37.6
56.5
mass per fuel mass (raw)
mg/kg
956.8
312.6
809.8
719.8
882.8
1414.9
mass per equivalent dry fuel mass
mg/kg
944.9
263.6
848.8
771.0
822.5
1337.4
mass per fuel energy
mg/MJ
51.6
14.4
46.4
42.1
44.9
73.0
mass per time
mg/hour
362.3
85.7
313.7
319.1
325.8
490.7
CO total mass
g
8.42
0.47
9.07
8.24
7.96
8.39
mass per volume of water remaining
g/liter
1.96
0.12
2.12
1.92
1.85
1.93
mass per fuel mass (raw)
g/kg
43.91
5.02
46.81
37.08
43.35
48.39
mass per equivalent dry fuel mass
g/kg
43.73
4.47
49.07
39.72
40.39
45.74
mass per fuel energy
g/MJ
2.39
0.24
2.68
2.17
2.21
2.50
mass per time
g/hour
16.84
0.92
18.14
16.44
16.00
16.78
C02 total mass
g
325
6
320
333
323
323
mass per volume of water remaining
g/liter
76
2
75
78
75
74
mass per fuel mass (raw)
g/kg
1,694
157
1,652
1,499
1,760
1,865
mass per equivalent dry fuel mass
g/kg
1,685
74
1,732
1,605
1,640
1,763
mass per fuel energy
g/MJ
92
4
95
88
90
96
mass per time
g/hour
650
10
640
664
650
647
THC (as CsHs) total mass
g
0.58
0.11
no1
0.56
0.69
0.48
mass per volume of water remaining
g/liter
0.13
0.03
no1
0.13
0.16
0.11
mass per fuel mass (raw)
g/kg
3.01
0.67
no1
2.51
3.77
2.74
mass per equivalent dry fuel mass
g/kg
2.93
0.51
no1
2.69
3.52
2.59
mass per fuel energy
g/MJ
0.16
0.03
no1
0.15
0.19
0.14
mass per time
g/hour
1.15
0.22
no1
1.11
1.39
0.95
CH4 total mass
g
0.19
0.04
0.20
0.13
0.20
0.21
mass per volume of water remaining
g/liter
0.04
0.01
0.05
0.03
0.05
0.05
mass per fuel mass (raw)
g/kg
0.99
0.27
1.05
0.60
1.10
1.20
mass per equivalent dry fuel mass
g/kg
0.98
0.23
1.10
0.64
1.03
1.14
mass per fuel energy
g/MJ
0.05
0.01
0.06
0.03
0.06
0.06
mass per time
g/hour
0.37
0.07
0.41
0.27
0.41
0.42
NOx total mass
g
0.12
0.01
0.12
0.13
0.13
0.11
mass per volume of water remaining
g/liter
0.03
0.00
0.03
0.03
0.03
0.02
mass per fuel mass (raw)
g/kg
0.63
0.04
0.60
0.60
0.69
0.62
mass per equivalent dry fuel mass
g/kg
0.62
0.02
0.62
0.64
0.64
0.59
mass per fuel energy
g/MJ
0.03
0.00
0.03
0.03
0.04
0.03
mass per time
g/hour
0.24
0.02
0.23
0.26
0.26
0.22
1 THC data rejected and not included because it did not meet QA acceptance criteria per Table 17.
11
-------
OC (organic carbon) and EC (elemental carbon) particulate emissions were measured using NIOSH
Method 5040 (12), and results are reported for low-moisture fuel in Table 4. Particulate samples were
collected on quartz fiber filters, and gas-phase samples were also collected on quartz fiber filters
downstream of PTFE membrane filters to account for the gas-phase absorption artifact (13). Mass
fractions of organic and elemental carbon to total carbon in particulate matter are reported in Table 5.
Table 4. Low-moisture fuel - emissions ofOC (organic carbon) and EC (elemental carbon) in PM2.s
Parameter Units Average
SD Test 1 Test 2 Test 3
Test 4
High-power cold-start
OC temperature-corrected total mass
mg
91.7
16.5
no1
73.6
106.0
95.7
mass per effective volume of water boiled
mg/liter
19.0
3.4
no1
15.3
21.9
19.7
mass per fuel mass (raw)
mg/kg
196.8
33.3
no1
160.0
224.7
205.7
mass per equivalent dry fuel mass
mg/kg
274.0
58.4
no1
206.6
307.7
307.7
mass per fuel energy
mg/MJ
15.0
3.2
no1
11.3
16.8
16.8
mass per useful energy delivered (to water in pot)
mg/MJ
48.1
9.4
no1
37.7
55.9
50.9
mass per time
mg/hour
191.8
34.3
no1
152.5
207.9
215.1
EC temperature-corrected total mass
mg
241.2
55.2
no1
230.5
301.0
192.2
mass per effective volume of water boiled
mg/liter
49.9
11.4
no1
47.8
62.2
39.7
mass per fuel mass (raw)
mg/kg
517.6
113.5
no1
501.2
638.4
413.3
mass per equivalent dry fuel mass
mg/kg
713.2
140.2
no1
647.3
874.2
618.0
mass per fuel energy
mg/MJ
38.9
7.7
no1
35.4
47.7
33.8
mass per useful energy delivered (to water in pot)
mg/MJ
126.3
29.2
no1
118.0
158.8
102.2
mass per time
mg/hour
500.2
81.7
no1
477.7
590.7
432.1
High-power hot-start
OC temperature-corrected total mass
mg
89.8
43.8
53.3
153.5
75.2
77.4
mass per effective volume of water boiled
mg/liter
18.6
9.1
11.1
31.9
15.4
16.1
mass per fuel mass (raw)
mg/kg
213.1
98.8
130.3
356.4
185.2
180.4
mass per equivalent dry fuel mass
mg/kg
295.0
117.4
178.6
458.1
279.8
263.4
mass per fuel energy
mg/MJ
16.1
6.4
9.8
25.0
15.3
14.4
mass per useful energy delivered (to water in pot)
mg/MJ
47.1
21.6
28.8
78.3
40.9
40.3
mass per time
mg/hour
251.6
94.4
148.3
376.6
251.6
230.1
EC temperature-corrected total mass
mg
311.6
95.3
256.8
448.4
237.4
303.6
mass per effective volume of water boiled
mg/liter
64.6
19.9
53.4
93.1
48.7
63.0
mass per fuel mass (raw)
mg/kg
740.4
206.9
627.9
1041.2
584.8
707.8
mass per equivalent dry fuel mass
mg/kg
1029.0
219.8
860.9
1338.1
883.5
1033.4
mass per fuel energy
mg/MJ
56.2
12.0
47.0
73.1
48.3
56.4
mass per useful energy delivered (to water in pot)
mg/MJ
163.7
45.0
138.7
228.8
129.3
158.1
mass per time
mg/hour
878.0
166.9
714.6
1100.0
794.6
902.6
Low-power (30-minute simmer)
OC total mass
mg
89.3
39.0
54.7
78.5
78.6
145.3
mass per volume of water remaining
mg/liter
20.7
8.9
12.8
18.3
18.2
33.5
mass per fuel mass (raw)
mg/kg
475.2
249.1
282.1
352.9
427.9
838.0
mass per equivalent dry fuel mass
mg/kg
466.1
221.8
295.7
378.0
398.7
792.1
mass per fuel energy
mg/MJ
25.5
12.1
16.2
20.6
21.8
43.3
mass per time
mg/hour
178.6
78.0
109.3
156.5
157.9
290.6
EC total mass
mg
80.1
12.4
84.4
89.4
61.7
84.8
mass per volume of water remaining
mg/liter
18.6
2.9
19.7
20.9
14.3
19.5
mass per fuel mass (raw)
mg/kg
415.7
64.1
435.6
402.2
336.0
489.1
mass per equivalent dry fuel mass
mg/kg
415.7
69.8
456.6
430.8
313.1
462.3
mass per fuel energy
mg/MJ
22.7
3.8
24.9
23.5
17.1
25.2
mass per time
mg/hour
160.2
24.5
168.8
178.3
124.0
169.6
1 Test 1 rejected and not included due to improper ignition of fuel
12
-------
Table 5. Low-moisture fuel - PM2.s mass fractions of organic carbon to total carbon (OC/TC)
and elemental carbon to total carbon (EC/TC)
High-Power Cold-Start
High-Power Hot-Start
Low-Power (Simmer)
Mass fraction of OC/TC
0.275
0.224
0.527
Mass fraction of EC/TC
0.725
0.776
0.473
BC (black carbon) was measured with a microAeth® Model AE51 (AethLabs, San Francisco, CA, USA)
aethalometer, and results are reported for low-moisture fuel in Table 6.
Table 6. Low-moisture fuel - emissions ofBC (black carbon) measured with aethalometer
Parameter
Units
Average
SD
Test 1
Test 2
Test 3
Test 4
High-power cold-start
BC temperature-corrected total mass
mg
259.7
72.9
no1
239.3
340.6
199.2
mass per effective volume of water boiled
mg/liter
53.7
15.1
no1
49.6
70.4
41.1
mass per fuel mass (raw)
mg/kg
557.0
150.4
no1
520.2
722.4
428.5
mass per equivalent dry fuel mass
mg/kg
767.2
192.8
no1
671.9
989.1
640.8
mass per fuel energy
mg/MJ
41.9
10.5
no1
36.7
54.0
35.0
mass per useful energy delivered (to water in pot)
mg/MJ
136.0
38.7
no1
122.5
179.6
106.0
mass per time
mg/hour
537.4
116.0
no1
495.8
668.4
447.9
High-power hot-start
BC temperature-corrected total mass
mg
333.1
101.0
305.9
473.2
232.6
320.7
mass per effective volume of water boiled
mg/liter
69.0
21.1
63.7
98.2
47.8
66.5
mass per fuel mass (raw)
mg/kg
791.9
220.7
747.9
1098.9
573.0
747.7
mass per equivalent dry fuel mass
mg/kg
1098.8
229.5
1025.5
1412.3
865.7
1091.7
mass per fuel energy
mg/MJ
60.0
12.5
56.0
77.1
47.3
59.6
mass per useful energy delivered (to water in pot)
mg/MJ
175.1
48.0
165.3
241.5
126.7
167.0
mass per time
mg/hour
936.1
166.2
851.2
1161.0
778.6
953.5
Low-power (30-minute simmer)
BC total mass
mg
78.9
12.2
90.9
78.1
62.4
84.3
mass per volume of water remaining
mg/liter
18.3
2.9
21.3
18.2
14.5
19.4
mass per fuel mass (raw)
mg/kg
411.5
76.9
469.4
351.1
339.5
486.0
mass per equivalent dry fuel mass
mg/kg
410.9
79.7
492.0
376.1
316.3
459.3
mass per fuel energy
mg/MJ
22.4
4.4
26.9
20.5
17.3
25.1
mass per time
mg/hour
157.8
24.2
181.8
155.7
125.3
168.5
1 Test 1 rejected and not included due to improper ignition of fuel
Test Results for High-Moisture Fuel
Tabulated data for the BioLite HomeStove with high-moisture fuel are shown in Tables 7-12 in the same
format as Tables 1-6, as described in the previous section for low-moisture fuel. A side-by-side
comparison of data for low- and high-moisture fuels is provided in Tables 13-15. Results for high-
moisture "green" wood fuel are indicated by the green background color in the tables, while results for
low-moisture (dry) fuel are indicated by the tan color. Moisture content was approximately 30 percent
(wet basis) for high-moisture wood fuel, but some low-moisture fuel was required for starting the fire
and maintaining combustion. Fuel moisture content is reported as the average (on a mass basis) of low-
and high-moisture fuels, as described in Jetter et al. - see Supporting Information (11).
13
-------
Table 7. High-moisture fuel, high-power cold-start - WBT, PM2.5, and gaseous pollutant parameters
Parameter
Units
Average
SD
Test 1
Test 2
Test 3
Test 4
Fuel moisture (wet basis)
%
17.6
2.47
19.9
19.2
14.5
16.7
Fuel consumed (raw)
g
843.4
61.4
860.3
886.1
752.7
874.4
Equivalent dry fuel consumed
g
561.7
26.9
556.1
568.5
528.8
593.4
Time to boil 5 liters of water, 25 to 100°C
min
58.38
2.0
56.80
61.15
57.06
58.49
Thermal efficiency
%
25.5
0.6
25.0
25.2
25.4
26.3
Fuel burning rate
g/min
9.3
0.3
9.5
9.1
8.9
9.6
Temperature-corrected specific fuel consumption
g/liter
119.5
6.4
118.9
122.7
110.8
125.5
Temperature-corrected specific energy use
kJ/l iter
2189
118
2179
2249
2029
2300
Fire power
W
2829
104
2912
2765
2717
2922
Cooking power
W
721
36
728
696
690
769
Modified combustion efficiency
%
98.5
0.1
98.4
98.4
98.4
98.7
PM2.5 temperature-corrected total mass
mg
628.5
59.6
683.6
565.2
636.6
no1
mass per effective volume of water boiled
mg/liter
138.1
12.4
150.1
125.3
138.9
no1
mass per fuel mass (raw)
mg/kg
783.8
116.2
815.8
654.9
880.7
no1
mass per equivalent dry fuel mass
mg/kg
1178.8
136.9
1262.0
1020.8
1253.6
no1
mass per fuel energy
mg/MJ
64.3
7.5
68.8
55.7
68.4
no1
mass per useful energy delivered (to water in pot)
mg/MJ
255.3
29.7
275.2
221.2
269.4
no1
mass per time
mg/hour
648.7
85.6
722.1
554.6
669.4
no1
CO temperature-corrected total mass
g
9.52
0.83
9.67
10.59
9.19
8.64
mass per effective volume of water boiled
g/liter
2.10
0.18
2.12
2.35
2.00
1.94
mass per fuel mass (raw)
g/kg
11.75
0.98
11.54
12.27
12.71
10.48
mass per equivalent dry fuel mass
g/kg
17.63
1.56
17.85
19.13
18.10
15.44
mass per fuel energy
g/MJ
0.96
0.09
0.97
1.04
0.99
0.84
mass per useful energy delivered (to water in pot)
g/MJ
3.78
0.40
3.89
4.14
3.89
3.20
mass per time
g/hour
9.78
0.68
10.21
10.39
9.66
8.87
C02 temperature-corrected total mass
g
975
51
964
1,015
907
1,013
mass per effective volume of water boiled
g/liter
215
14
212
225
198
227
mass per fuel mass (raw)
g/kg
1,203
48
1,151
1,176
1,255
1,229
mass per equivalent dry fuel mass
g/kg
1,803
24
1,780
1,833
1,787
1,810
mass per fuel energy
g/MJ
98
1
97
100
97
99
mass per useful energy delivered (to water in pot)
g/MJ
386
9
388
397
384
375
mass per time
g/hour
1,002
37
1,018
996
954
1,040
THC (as CsHs) temperature-corrected total mass
g
1.39
0.31
1.53
1.59
1.52
0.94
mass per effective volume of water boiled
g/liter
0.31
0.07
0.34
0.35
0.33
0.21
mass per fuel mass (raw)
g/kg
1.73
0.41
1.83
1.84
2.10
1.14
mass per equivalent dry fuel mass
g/kg
2.59
0.61
2.83
2.87
2.98
1.68
mass per fuel energy
g/MJ
0.14
0.03
0.15
0.16
0.16
0.09
mass per useful energy delivered (to water in pot)
g/MJ
0.56
0.14
0.62
0.62
0.64
0.35
mass per time
g/hour
1.43
0.32
1.62
1.56
1.59
0.96
CH4 temperature-corrected total mass
g
0.30
0.09
0.29
0.40
0.31
0.19
mass per effective volume of water boiled
g/liter
0.07
0.02
0.06
0.09
0.07
0.04
mass per fuel mass (raw)
g/kg
0.36
0.11
0.34
0.46
0.43
0.23
mass per equivalent dry fuel mass
g/kg
0.55
0.16
0.53
0.71
0.61
0.33
mass per fuel energy
g/MJ
0.03
0.01
0.03
0.04
0.03
0.02
mass per useful energy delivered (to water in pot)
g/MJ
0.12
0.04
0.12
0.15
0.13
0.07
mass per time
g/hour
0.30
0.08
0.30
0.39
0.33
0.19
NOx temperature-corrected total mass
g
0.42
0.04
0.42
0.44
0.37
0.45
mass per effective volume of water boiled
g/liter
0.09
0.01
0.09
0.10
0.08
0.10
mass per fuel mass (raw)
g/kg
0.52
0.02
0.50
0.51
0.51
0.55
mass per equivalent dry fuel mass
g/kg
0.78
0.04
0.77
0.80
0.73
0.81
mass per fuel energy
g/MJ
0.04
0.00
0.04
0.04
0.04
0.04
mass per useful energy delivered (to water in pot)
g/MJ
0.17
0.01
0.17
0.17
0.16
0.17
mass per time
g/hour
0.43
0.03
0.44
0.44
0.39
0.47
1 PM2.5 data rejected and not included due to a damaged filter
14
-------
Table 8. High-moisture fuel, high-power hot-start - WBT, PM2.5, and gaseous pollutant parameters
Parameter
Units
Average
SD
Test 1
Test 2
Test 41
Fuel moisture (wet basis)
%
19.0
1.02
19.8
19.3
17.8
Fuel consumed (raw)
g
678.7
44.2
630.9
718.0
687.3
Equivalent dry fuel consumed
g
451.5
36.7
409.2
471.4
473.9
Time to boil 5 liters of water, 25 to 100°C
min
38.00
3.2
34.33
40.20
39.48
Thermal efficiency
%
27.7
0.9
28.7
27.5
26.9
Fuel burning rate
g/min
11.4
0.1
11.6
11.4
11.3
Temperature-corrected specific fuel consumption
g/liter
92.2
7.6
83.8
98.6
94.3
Temperature-corrected specific energy use
kJ/l iter
1690
140
1535
1806
1728
Fire power
W
3488
44
3536
3478
3449
Cooking power
W
966
44
1015
955
928
Modified combustion efficiency
%
98.9
0.1
98.8
98.9
99.0
PM2.5 temperature-corrected total mass
mg
305.1
23.0
291.0
292.7
331.7
mass per effective volume of water boiled
mg/liter
64.8
4.7
61.3
63.0
70.2
mass per fuel mass (raw)
mg/kg
469.0
46.9
474.8
419.6
512.8
mass per equivalent dry fuel mass
mg/kg
705.0
57.3
732.1
639.1
743.7
mass per fuel energy
mg/MJ
38.5
3.1
39.9
34.9
40.6
mass per useful energy delivered (to water in pot)
mg/MJ
139.0
11.9
139.2
127.0
150.9
mass per time
mg/hour
483.2
40.3
508.7
436.8
504.1
CO temperature-corrected total mass
g
5.29
0.33
5.22
5.66
5.01
mass per effective volume of water boiled
g/liter
1.13
0.08
1.10
1.22
1.06
mass per fuel mass (raw)
g/kg
8.12
0.38
8.51
8.11
7.74
mass per equivalent dry fuel mass
g/kg
12.23
0.95
13.12
12.36
11.23
mass per fuel energy
g/MJ
0.67
0.05
0.72
0.67
0.61
mass per useful energy delivered (to water in pot)
g/MJ
2.41
0.12
2.50
2.46
2.28
mass per time
g/hour
8.39
0.76
9.12
8.44
7.61
C02 temperature-corrected total mass
g
748
64.64
674
784
787
mass per effective volume of water boiled
g/liter
159
14.87
142
169
167
mass per fuel mass (raw)
g/kg
1,147
62.39
1,099
1,124
1,218
mass per equivalent dry fuel mass
g/kg
1,724
36.94
1,695
1,712
1,766
mass per fuel energy
g/MJ
94
2.02
92
93
96
mass per useful energy delivered (to water in pot)
g/MJ
340
17.97
322
340
358
mass per time
g/hour
1,182
13.85
1,178
1,170
1,197
THC (as CsHs) temperature-corrected total mass
g
0.60
0.10
0.71
0.58
0.51
mass per effective volume of water boiled
g/liter
0.13
0.02
0.15
0.12
0.11
mass per fuel mass (raw)
g/kg
0.92
0.20
1.16
0.83
0.78
mass per equivalent dry fuel mass
g/kg
1.40
0.34
1.79
1.27
1.14
mass per fuel energy
g/MJ
0.08
0.02
0.10
0.07
0.06
mass per useful energy delivered (to water in pot)
g/MJ
0.27
0.06
0.34
0.25
0.23
mass per time
g/hour
0.96
0.25
1.24
0.87
0.77
CH4 temperature-corrected total mass
g
0.13
0.04
0.17
0.14
0.09
mass per effective volume of water boiled
g/liter
0.03
0.01
0.04
0.03
0.02
mass per fuel mass (raw)
g/kg
0.21
0.07
0.28
0.19
0.14
mass per equivalent dry fuel mass
g/kg
0.31
0.12
0.44
0.30
0.21
mass per fuel energy
g/MJ
0.02
0.01
0.02
0.02
0.01
mass per useful energy delivered (to water in pot)
g/MJ
0.06
0.02
0.08
0.06
0.04
mass per time
g/hour
0.22
0.08
0.30
0.20
0.14
NOx temperature-corrected total mass
g
0.33
0.05
0.28
0.38
0.33
mass per effective volume of water boiled
g/liter
0.07
0.01
0.06
0.08
0.07
mass per fuel mass (raw)
g/kg
0.51
0.04
0.46
0.54
0.52
mass per equivalent dry fuel mass
g/kg
0.76
0.06
0.71
0.83
0.75
mass per fuel energy
g/MJ
0.04
0.00
0.04
0.05
0.04
mass per useful energy delivered (to water in pot)
g/MJ
0.15
0.01
0.13
0.16
0.15
mass per time
g/hour
0.52
0.04
0.49
0.56
0.51
1 Test 3 rejected and not included due to burning rate too high
15
-------
Table 9. High-moisture fuel, low-power (30-min simmer) - WBT and pollutant emission parameters
Parameter
Units
Average
SD
Test 1
Test 2
Test 3
Fuel moisture (wet basis)
%
22.01
0.48
22.45
22.09
21.49
Fuel consumed (raw)
g
327.4
20.1
306.7
346.8
328.6
Equivalent dry fuel consumed
g
234.4
4.6
230.9
232.6
239.6
Fuel burning rate
g/min
7.9
0.2
7.7
8.0
8.0
Specific fuel consumption
g/liter
55.5
1.4
53.9
55.9
56.6
Specific energy use
kJ/liter
1017
26
987
1025
1038
Fire power
W
2414
55
2350
2451
2440
Modified combustion efficiency
%
97.3
0.4
97.1
97.7
96.9
PM2.5 total mass
mg
346.3
40.6
299.6
365.7
373.6
mass per volume of water remaining
mg/liter
82.0
10.5
69.9
87.9
88.3
mass per fuel mass (raw)
mg/kg
1056.1
80.0
977.0
1054.5
1136.9
mass per equivalent dry fuel mass
mg/kg
1476.4
154.7
1297.9
1572.2
1559.1
mass per fuel energy
mg/MJ
80.5
8.4
70.8
85.8
85.0
mass per time
mg/hour
701.2
88.4
599.3
757.1
747.2
CO total mass
g
7.52
1.45
7.50
6.08
8.99
mass per volume of water remaining
g/liter
1.78
0.33
1.75
1.46
2.12
mass per fuel mass (raw)
g/kg
23.12
5.04
24.46
17.54
27.34
mass per equivalent dry fuel mass
g/kg
32.05
5.68
32.49
26.16
37.50
mass per fuel energy
g/MJ
1.75
0.31
1.77
1.43
2.05
mass per time
g/hour
15.19
2.69
15.00
12.60
17.97
C02 total mass
g
418
22
400
411
443
mass per volume of water remaining
g/liter
99
6
93
99
105
mass per fuel mass (raw)
g/kg
1,279
84
1,305
1,185
1,347
mass per equivalent dry fuel mass
g/kg
1,783
59
1,734
1,767
1,848
mass per fuel energy
g/MJ
97
3
95
96
101
mass per time
g/hour
846
43
801
851
886
THC (as CsHs) total mass
g
1.12
0.43
0.75
1.02
1.59
mass per volume of water remaining
g/liter
0.27
0.10
0.17
0.25
0.38
mass per fuel mass (raw)
g/kg
3.41
1.27
2.44
2.94
4.84
mass per equivalent dry fuel mass
g/kg
4.75
1.73
3.24
4.38
6.64
mass per fuel energy
g/MJ
0.26
0.09
0.18
0.24
0.36
mass per time
g/hour
2.26
0.85
1.50
2.11
3.18
CH4 total mass
g
0.28
0.13
0.19
0.22
0.43
mass per volume of water remaining
g/liter
0.07
0.03
0.04
0.05
0.10
mass per fuel mass (raw)
g/kg
0.84
0.39
0.61
0.63
1.30
mass per equivalent dry fuel mass
g/kg
1.17
0.53
0.81
0.93
1.78
mass per fuel energy
g/MJ
0.06
0.03
0.04
0.05
0.10
mass per time
g/hour
0.56
0.26
0.37
0.45
0.85
NOx total mass
g
0.16
0.02
0.15
0.17
0.17
mass per volume of water remaining
g/liter
0.04
0.00
0.03
0.04
0.04
mass per fuel mass (raw)
g/kg
0.50
0.03
0.47
0.50
0.53
mass per equivalent dry fuel mass
g/kg
0.70
0.06
0.63
0.74
0.72
mass per fuel energy
g/MJ
0.04
0.00
0.03
0.04
0.04
mass per time
g/hour
0.33
0.04
0.29
0.36
0.35
16
-------
Table 10. High-moisture fuel - emissions ofPM2.s OC (organic carbon) and EC (elemental carbon)
Parameter Units Average SD
Test 1 Test 2 Test 3 Test 4
High-power cold-start
OC temperature-corrected total mass
mg
402.6
92.4
501.4
388.1
318.3
no1
mass per effective volume of water boiled
mg/liter
88.5
20.5
110.1
86.0
69.4
no1
mass per fuel mass (raw)
mg/kg
496.1
88.7
598.4
449.7
440.4
no1
mass per equivalent dry fuel mass
mg/kg
751.2
155.6
925.7
700.9
626.9
no1
mass per fuel energy
mg/MJ
41.0
8.5
50.5
38.2
34.2
no1
mass per useful energy delivered (to water in pot)
mg/MJ
162.8
34.9
201.9
151.9
134.7
no1
mass per time
mg/hour
415.1
101.9
529.7
380.8
334.7
no1
EC temperature-corrected total mass
mg
165.2
67.5
225.5
178.0
92.3
no1
mass per effective volume of water boiled
mg/liter
36.4
14.9
49.5
39.5
20.1
no1
mass per fuel mass (raw)
mg/kg
201.0
70.8
269.1
206.2
127.6
no1
mass per equivalent dry fuel mass
mg/kg
306.5
118.0
416.2
321.4
181.7
no1
mass per fuel energy
mg/MJ
16.7
6.4
22.7
17.5
9.9
no1
mass per useful energy delivered (to water in pot)
mg/MJ
66.5
26.0
90.8
69.6
39.1
no1
mass per time
mg/hour
169.9
70.7
238.2
174.6
97.0
no1
High-power hot-start
OC temperature-corrected total mass
mg
107.0
45.4
137.2
129.1
no2
54.8
mass per effective volume of water boiled
mg/liter
22.8
9.7
28.9
27.8
no2
11.6
mass per fuel mass (raw)
mg/kg
164.6
71.8
223.9
185.1
no2
84.7
mass per equivalent dry fuel mass
mg/kg
250.0
114.6
345.3
282.0
no2
122.9
mass per fuel energy
mg/MJ
13.6
6.3
18.8
15.4
no2
6.7
mass per useful energy delivered (to water in pot)
mg/MJ
48.9
21.3
65.6
56.0
no2
24.9
mass per time
mg/hour
172.0
80.3
239.9
192.7
no2
83.3
EC temperature-corrected total mass
mg
207.1
11.0
197.4
219.0
no2
205.0
mass per effective volume of water boiled
mg/liter
44.0
2.8
41.6
47.2
no2
43.4
mass per fuel mass (raw)
mg/kg
317.7
4.1
322.0
314.0
no2
317.0
mass per equivalent dry fuel mass
mg/kg
478.2
18.4
496.5
478.3
no2
459.7
mass per fuel energy
mg/MJ
26.1
1.0
27.1
26.1
no2
25.1
mass per useful energy delivered (to water in pot)
mg/MJ
94.2
0.9
94.4
95.0
no2
93.3
mass per time
mg/hour
327.8
16.7
345.0
326.9
no2
311.6
Low-power (30-minute simmer)
OC total mass
mg
225.1
44.9
187.6
274.9
212.8
no3
mass per volume of water remaining
mg/liter
53.4
11.5
43.8
66.1
50.3
no3
mass per fuel mass (raw)
mg/kg
684.0
95.8
611.7
792.7
647.6
no3
mass per equivalent dry fuel mass
mg/kg
960.9
195.1
812.7
1181.9
888.1
no3
mass per fuel energy
mg/MJ
52.4
10.6
44.3
64.5
48.4
no3
mass per time
mg/hour
456.6
100.6
375.2
569.1
425.6
no3
EC total mass
mg
76.1
32.0
97.9
91.1
39.4
no3
mass per volume of water remaining
mg/liter
18.0
7.6
22.9
21.9
9.3
no3
mass per fuel mass (raw)
mg/kg
233.9
102.8
319.3
262.6
119.8
no3
mass per equivalent dry fuel mass
mg/kg
326.7
141.5
424.1
391.5
164.3
no3
mass per fuel energy
mg/MJ
17.8
7.7
23.1
21.4
9.0
no3
mass per time
mg/hour
154.4
65.6
195.8
188.5
78.7
no3
1 Data rejected and not included due to a damaged filter
2 Test 3 rejected and not included due to fuel burning rate too high
3 Test 4 rejected and not included due to fuel burning rate too high
Table 11. High-moisture fuel - PM2.s mass fractions of organic carbon to total carbon (OC/TC)
and elemental carbon to total carbon (EC/TC)
High-Power Cold-Start
High-Power Hot-Start
Low-Power (Simmer)
Mass fraction of OC/TC
0.709
0.341
0.747
Mass fraction of EC/TC
0.291
0.659
0.253
17
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Table 12. High-moisture fuel - emissions of BC (black carbon) measured with aethalometer
Parameter
Units
Average
SD
Test 1
Test 2
Test 3
Test 4
High-power cold-start
BC temperature-corrected total mass
mg
246.9
101.5
264.5
200.6
142.8
379.7
mass per effective volume of water boiled
mg/liter
54.7
23.1
58.1
44.5
31.2
85.2
mass per fuel mass (raw)
mg/kg
301.5
116.9
315.7
232.4
197.6
460.3
mass per equivalent dry fuel mass
mg/kg
452.6
172.9
488.4
362.3
281.3
678.3
mass per fuel energy
mg/MJ
24.7
9.4
26.6
19.8
15.3
37.0
mass per useful energy delivered (to water in pot)
mg/MJ
96.5
35.0
106.5
78.5
60.4
140.7
mass per time
mg/hour
254.0
105.0
279.4
196.8
150.2
389.5
High-power hot-start
BC temperature-corrected total mass
mg
216.8
26.2
187.3
225.7
no1
237.4
mass per effective volume of water boiled
mg/liter
46.1
5.8
39.5
48.6
no1
50.2
mass per fuel mass (raw)
mg/kg
332.1
31.6
305.6
323.5
no1
367.0
mass per equivalent dry fuel mass
mg/kg
498.8
30.9
471.3
492.8
no1
532.3
mass per fuel energy
mg/MJ
27.2
1.7
25.7
26.9
no1
29.0
mass per useful energy delivered (to water in pot)
mg/MJ
98.5
9.2
89.6
97.9
no1
108.0
mass per time
mg/hour
341.7
17.2
327.5
336.8
no1
360.8
Low-power (30-minute simmer)
BC total mass
mg
81.4
21.8
95.3
92.5
56.2
no2
mass per volume of water remaining
mg/liter
19.3
5.2
22.2
22.2
13.3
no2
mass per fuel mass (raw)
mg/kg
249.5
71.5
310.8
266.9
171.0
no2
mass per equivalent dry fuel mass
mg/kg
348.4
98.9
412.8
397.9
234.5
no2
mass per fuel energy
mg/MJ
19.0
5.4
22.5
21.7
12.8
no2
mass per time
mg/hour
164.9
45.4
190.6
191.6
112.4
no2
1 Test 3 rejected and not included due to fuel burning rate too high
2 Test 4 rejected and not included due to fuel burning rate too high
18
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Table 13. Comparison of low- and high-moisture fuel - WBT, PM2.5 and gaseous pollutants
Parameter
Units
High-power
cold-start
High-power
hot-start
Low-power
30-minute simmer
Fuel moisture (wet basis)
%
8.3
17.6
8.5
19.0
8.5
22.0
Fuel consumed (raw)
g
488.9
843.4
436.5
678.7
193.3
327.4
Equivalent dry fuel consumed
g
354.1
561.7
311.7
451.5
193.2
234.4
Time to boil 5 liters of water, 25 to 100°C
min
28.74
58.38
21.03
38.00
n.a.1
n.a.1
Thermal efficiency
%
31.0
25.5
34.7
27.7
n.a.1
n.a.1
Fuel burning rate
g/min
11.7
9.3
14.3
11.4
6.4
7.9
Temperature-corrected specific fuel consumption
g/liter
69.7
119.5
61.9
92.2
44.9
55.5
Temperature-corrected specific energy use
kJ/l iter
1277
2189
1134
1690
822
1017
Fire power
W
3582
2829
4355
3488
1966
2414
Cooking power
W
1110
721
1515
966
n.a.1
n.a.1
Modified combustion efficiency
%
99.4
98.5
99.5
98.9
96.1
97.3
PM2.5 temperature-corrected total mass
mg
264.0
628.5
327.9
305.1
181.1
346.3
mass per effective volume of water
mg/liter
54.6
138.1
67.9
64.8
42.0
82.0
mass per fuel mass (raw)
mg/kg
566.6
783.8
779.8
469.0
956.8
1056.1
mass per equivalent dry fuel mass
mg/kg
783.1
1178.8
1084.6
705.0
944.9
1476.4
mass per fuel energy
mg/MJ
42.8
64.3
59.2
38.5
51.6
80.5
mass per useful energy delivered (to water in pot)
mg/MJ
138.3
255.3
172.4
139.0
n.a.1
n.a.1
mass per time
mg/hour
549.3
648.7
925.8
483.2
362.3
701.2
CO temperature-corrected total mass
g
2.20
9.52
1.55
5.29
8.42
7.52
mass per effective volume of water
g/liter
0.45
2.10
0.32
1.13
1.96
1.78
mass per fuel mass (raw)
g/kg
4.72
11.75
3.70
8.12
43.91
23.12
mass per equivalent dry fuel mass
g/kg
6.50
17.63
5.16
12.23
43.73
32.05
mass per fuel energy
g/MJ
0.36
0.96
0.28
0.67
2.39
1.75
mass per useful energy delivered (to water in pot)
g/MJ
1.15
3.78
0.82
2.41
n.a.1
n.a.1
mass per time
g/hour
4.59
9.78
4.40
8.39
16.84
15.19
C02 temperature-corrected total mass
g
565
975
488
748
325
418
mass per effective volume of water
g/liter
117
215
101
159
76
99
mass per fuel mass (raw)
g/kg
1,213
1,203
1,165
1,147
1,694
1,279
mass per equivalent dry fuel mass
g/kg
1,680
1,803
1,637
1,724
1,685
1,783
mass per fuel energy
g/MJ
92
98
89
94
92
97
mass per useful energy delivered (to water in pot)
g/MJ
296
386
258
340
n.a.1
n.a.1
mass per time
g/hour
1,183
1,002
1,404
1,182
650
846
THC (as CsHs) temperature-corrected total mass
g
0.25
1.39
0.22
0.60
0.58
1.12
mass per effective volume of water
g/liter
0.05
0.31
0.05
0.13
0.13
0.27
mass per fuel mass (raw)
g/kg
0.54
1.73
0.52
0.92
3.01
3.41
mass per equivalent dry fuel mass
g/kg
0.75
2.59
0.75
1.40
2.93
4.75
mass per fuel energy
g/MJ
0.04
0.14
0.04
0.08
0.16
0.26
mass per useful energy delivered (to water in pot)
g/MJ
0.13
0.56
0.12
0.27
n.a.1
n.a.1
mass per time
g/hour
0.53
1.43
0.65
0.96
1.20
2.26
CH4 temperature-corrected total mass
g
0.06
0.30
0.03
0.13
0.19
0.28
mass per effective volume of water
g/liter
0.01
0.07
0.01
0.03
0.04
0.07
mass per fuel mass (raw)
g/kg
0.12
0.36
0.07
0.21
0.99
0.84
mass per equivalent dry fuel mass
g/kg
0.17
0.55
0.10
0.31
0.98
1.17
mass per fuel energy
g/MJ
0.01
0.03
0.01
0.02
0.05
0.06
mass per useful energy delivered (to water in pot)
g/MJ
0.03
0.12
0.02
0.06
n.a.1
n.a.1
mass per time
g/hour
0.12
0.30
0.08
0.22
0.37
0.56
NOx temperature-corrected total mass
g
0.24
0.42
0.21
0.33
0.12
0.16
mass per effective volume of water
g/liter
0.05
0.09
0.04
0.07
0.03
0.04
mass per fuel mass (raw)
g/kg
0.51
0.52
0.50
0.51
0.63
0.50
mass per equivalent dry fuel mass
g/kg
0.71
0.78
0.70
0.76
0.62
0.70
mass per fuel energy
g/MJ
0.04
0.04
0.04
0.04
0.03
0.04
mass per useful energy delivered (to water in pot)
g/MJ
0.12
0.17
0.11
0.15
n.a.1
n.a.1
mass per time
g/hour
0.50
0.43
0.60
0.52
0.24
0.33
1Not applicable to the low-power 30-minute simmer phase
19
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Table 14. Comparison of low- and high-moisture fuel - PM2.5 organic and elemental carbon
Parameter
Units
High-power
cold-start
High-power
hot-start
Low-power
30-minute simmer
Fuel moisture (wet basis)
%
8.3
17.6
8.5
19.0
8.5
22.0
OC temperature-corrected total mass
mg
91.7
402.6
89.8
107.0
89.3
225.1
mass per effective volume of water
mg/liter
19.0
88.5
18.6
22.8
20.7
53.4
mass per fuel mass (raw)
mg/kg
196.8
496.1
213.1
164.6
475.2
684.0
mass per equivalent dry fuel mass
mg/kg
274.0
751.2
295.0
250.0
466.1
960.9
mass per fuel energy
mg/MJ
15.0
41.0
16.1
13.6
25.5
52.4
mass per useful energy delivered
mg/MJ
48.1
162.8
47.1
48.9
n.a.
n.a.
mass per time
mg/hour
191.8
415.1
251.6
172.0
178.6
456.6
EC temperature-corrected total mass
mg
241.2
165.2
311.6
207.1
80.1
76.1
mass per effective volume of water
mg/liter
49.9
36.4
64.6
44.0
18.6
18.0
mass per fuel mass (raw)
mg/kg
517.6
201.0
740.4
317.7
415.7
233.9
mass per equivalent dry fuel mass
mg/kg
713.2
306.5
1029.0
478.2
415.7
326.7
mass per fuel energy
mg/MJ
38.9
16.7
56.2
26.1
22.7
17.8
mass per useful energy delivered
mg/MJ
126.3
66.5
163.7
94.2
n.a.
n.a.
mass per time
mg/hour
500.2
169.9
878.0
327.8
160.2
154.4
Mass fraction of OC/TC
-
0.275
0.709
0.224
0.341
0.527
0.747
Mass fraction of EC/TC
-
0.725
0.291
0.776
0.659
0.473
0.253
Table 15. Comparison of low- and high-moisture fuel - emissions of black carbon (aethalometer)
Parameter
Units
High-power
cold-start
High-power
hot-start
Low-power
30-minute simmer
Fuel moisture (wet basis)
%
8.3
17.6
8.5
19.0
8.5
22.2
BC temperature-corrected total mass
mg
259.7
246.9
333.1
216.8
78.9
81.4
mass per effective volume of water
mg/liter
53.7
54.7
69.0
46.1
18.3
19.3
mass per fuel mass (raw)
mg/kg
557.0
301.5
791.9
332.1
411.5
249.5
mass per equivalent dry fuel mass
mg/kg
767.2
452.6
1098.8
498.8
410.9
348.4
mass per fuel energy
mg/MJ
41.9
24.7
60.0
27.2
22.4
19.0
mass per useful energy delivered
mg/MJ
136.0
96.5
175.1
98.5
n.a.
n.a.
mass per time
mg/hour
537.4
254.0
936.1
341.7
157.8
164.9
Discussion of Results and Observations
As shown in the Results Summary, the BioLite HomeStove's cooking power was 1313 W (average of
cold-start and hot-start test phases of the WBT) with low-moisture fuel. As shown in Figure 2, cooking
power for the HomeStove was similar to that of the 3-stone fire, while fire power for the HomeStove
was less due to its better efficiency. The HomeStove is rated at Tier 2 for Efficiency/Fuel Use, as shown
in Figure 3. MCE was better at high-power than at low-power, as shown in Figure 4. The previously
tested Philips HD4012 forced-draft stove had better thermal efficiency (without a pot skirt) and better
MCE at low-power, but it required extra fuelwood preparation (10 cm or less in length), while the
HomeStove has the advantage of using fuelwood sticks with long lengths - similar to fuelwood used in
many traditional stoves.
The HomeStove is rated at Tier 3 for Emissions, as shown in the Results Summary. CO emissions are
rated at Sub-Tier 4, and PM2.5 emissions are rated at Sub-Tiers 3 and 4 for high- and low-power,
respectively. The overall Tier rating is based on the lowest Sub-Tier rating, per the IWA. As shown in
Figures 5 and 6, many previously tested forced-draft and natural-draft stoves were rated at Sub-Tier 4
for CO emissions, but fewer stoves were rated at Sub-Tiers 3 or 4 for PM2.5 emissions. The HomeStove is
rated at the same Sub-Tiers for Emissions as the previously tested Philips HD4012 stove.
20
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As shown in the Results Summary, the HomeStove is rated at Tier 2 for Indoor Emissions, and the lowest
Sub-Tier value is for high-power PM2.5 emissions, as shown in Figure 7. Indoor Emissions Tiers are based
on emission rates (pollutant mass per time) into the household space. A stove with an effective
chimney could have relatively high Total Emissions (low Tier rating) but low Indoor Emissions (high Tier
rating). The HomeStove does not have a chimney.
The fraction of organic to total carbon in PM2.5 was greater at low-power than at high-power with low-
moisture fuel, as shown in Table 5. Elemental carbon is generally considered a reasonable proxy for
black carbon, but black carbon is not scientifically well defined yet. Black carbon emissions can be
operationally defined by an aethalometer instrument, as presented in Table 6. Discrepancies in mass
between EC and BC and between TC and PM2.5 may sometimes be observed due to the different
methods and measurement uncertainties.
As expected, performance was generally better with low-moisture fuel than with high-moisture fuel, as
shown in Tables 13-15. With low-moisture fuel, fuel consumption was lower, thermal efficiency was
higher, cooking power was higher, and air pollutant emissions were mostly lower. Emissions of particle-
phase organic carbon were lower with low-moisture fuel, and emissions of elemental and black carbon
were somewhat lower with high-moisture fuel, as shown in Tables 14-15.
Average cooking power was greater during the hot-start test phase (see Tables 2 and 8) than during the
cold-start (Tables 1 and 7), because the stove's thermal mass absorbs more heat during cold-start.
The HomeStove performed without any problems during testing. The HomeStove is simple to operate -
similar to typical rocket stoves. With its cast iron components, the HomeStove is similar in weight to
some portable stoves with ceramic components, and it is heavier than previously tested portable metal
stoves. BioLite has experience developing the successful CampStove for the recreational market, and
the HomeStove has a high-quality manufactured appearance. For more information, see the BioLite
web site (14).
Quality Assurance/Quality Control
A Quality Assurance Project Plan meeting EPA requirements (15) was prepared and was reviewed by an
EPA Quality Manager. Specifically, work was in compliance with Category II Quality Assurance Project
Plan requirements "...for important, highly visible Agency projects involving areas such as supporting the
development of environmental regulations and standards" (16).
An important indicator of overall data quality for cookstove performance testing is the carbon mass
balance. Carbon measured in the emissions is compared with carbon measured in the fuel consumed. A
percent difference based on carbon in the fuel is calculated for each test phase. A positive result
indicates that more carbon was measured in the fuel than in the emissions, and a negative result
indicates that less carbon was measured in fuel than in emissions. The absolute value of the percent
difference is used as a quality indicator and is considered to be excellent when < 10%, good when < 15%,
acceptable when < 20%, and unacceptable when > 20%. A continuous improvement process is used in
pursuit of excellent results, and tests are rejected when the carbon balance is > 20%. Carbon-balance
21
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results are shown in Table 16. Test replicates were rejected if the carbon balance or any other
measurement quality objectives (described below) were unacceptable.
Table 16. Carbon balance, percent difference based on fuel carbon
Fuel
Moisture
Test phase
Units
Test 1
Test 2
Test 3
Test 4
06/07/2013
06/20/2013
06/21/2013
06/25/2013
Low
High-power cold-start
%
Rejected1
10.6
11.4
-1.2
High-power hot-start
%
10.7
16.7
8.9
1.0
Low-power (simmer)
%
0.9
8.3
6.8
-0.2
07/09/2013
07/10/2013
02/21/2014
02/28/2014
High
High-power cold-start
%
3.1
0.0
-0.7
1.1
High-power hot-start
%
8.2
7.4
Rejected2
4.2
Low-power (simmer)
%
4.6
3.4
-7.2
Rejected3
1 Rejected due to improper ignition of fuel
2 Rejected due to fuel burning rate too high
3 Rejected due to fuel burning rate too high
The carbon balance is an overall indicator of many of the critical measurements included as
measurement quality objectives listed in Table 17. Test results included in this report were based on
measurements that met or exceeded these quality objectives. Data were rejected if measurements did
not meet acceptance criteria.
22
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Table 17. Measurement quality objectives for critical measurements.
All data included in this report were based on measurements that met or exceeded these objectives.
Measurement
Reference
Indicators
Acceptance
Criteria
Water and Fuel Mass,
Electronic Balance
EPA RTP Met Lab SOP,
MS-0501.0
Accuracy
Precision
±lg
±lg
Water Temperature,
Thermocouple
EPA RTP Met Lab SOP,
TH-0301.0
Accuracy
Precision
± 0.5 °C
± 0.5 °C
Fuel Heat of Combustion
ASTM D5865-04
Accuracy
Precision
± 0.5%
± 0.5%
Fuel Moisture Content Mass,
Electronic Balance
ASTM D4442-07
Accuracy
Precision
±lg
±0.5g
PM2.5 Mass,
Microbalance
EPA Method 5
Accuracy
Precision
± 0.01 mg
± 0.01 mg
PM2.5 Mass,
Sampling Air Flow
EPA RTP Met Lab SOP
FV-0237.1
Accuracy
Precision
± 1 Ipm
± 1 Ipm
SMPS sample flow rate
EPA RTP Met Lab SOP,
FV-0205.3
Flow cal., Classifier
Flow cal., CPC
± 1% of target
± 10% target
PM OC/EC Mass
NIOSH Method 5040
Accuracy
Precision
± 16.7%
± 10%
THC Concentration
CH4 Concentration
EPA Method 25A
Calibration linearity
Zero bias
Span bias
Zero drift
Span drift
± 2% of scale
± 5% of scale
± 5% of scale
± 3% of scale
± 3% of scale
CO Concentration
EPA Method 10
C02 Concentration
EPA Method 3A
NOx Concentration
EPA Method 7E
Duct Gas Velocity
EPA Methods 1 & 2
Accuracy
Precision
± 5% of reading
± 5% of reading
Duct Gas Temperature
Thermocouple
EPA RTP Met Lab SOP,
TH-0301.0
Accuracy
Precision
±1°C
±1°C
Acknowledgements
(Alphabetical Order)
Dale Greenwell, EPA Instrumentation
Jerroll Faircloth, Arcadis Instrumentation and Stove Operation
Michael Hays, EPA OC/EC Analysis
Amara Holder, EPA Aerosol Instrumentation
Laura Nessley, Arcadis Quality Assurance
Bakul Patel, EPA OC/EC Analysis
Chris Pressley, EPA Electronics Shop
Michael Tufts, Arcadis Metrology Laboratory
Richard Valentine, EPA Facilities
Craig Williams, Arcadis Project Lead
Robert Wright, EPA Quality Assurance
23
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References
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testing/learn-about-testing-protocols/protocols/downloads/wbt-protocol.pdf.
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http://www.iso.org/iso/catalogue_detail?csnumber=61975. IWA 11: 2012.
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12. NIOSH Method 5040, Diesel Particulate Matter. Atlanta, GA, USA : National Institute for
Occupational Safety and Health, 2003.
13. Measuring and simulating particulate organics in the atmosphere: problems and prospects.
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[Online] 2001. [Cited: September 26, 2014.] http://www.epa.gov/quality/qs-docs/r5-final.pdf.
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