BIBLIOGRAPHY
BATCAGAN, JERRY D. and FELWA, ALBANESE W. March 2008. Design
and Development of an Improved Biomass Cookstove for Institutional Use.Benguet State
University, La Trinidad, Benguet.
Adviser: ENGR. JOHN JAMES F. MALAMUG
ABSTRACT

The study aimed to design, develop and evaluate an improved biomass cookstove
for institutional cooking in terms of its average kindling time, average boiling time,
power, heat utilization efficiency and fuel consumption.
Over-all test results indicate that the improved biomass cookstove with a riser
height of 20 centimeters recorded the shortest boiling time, highest heat utilization
efficiency and lowest fuel consumption as compared to riser heights of 10, 30 and 40
centimeters. This makes the improved biomass cookstove to be more efficient at a riser
height of 20 centimeters.

The improved biomass cookstove having a height of 20 centimeters when further
compared to two traditional stoves namely the three-rock fire and metal plate stove
showed that the improved cookstove is more efficient than the two conventional stoves.
The improved cookstove was able to yield: shorter average kindling time, shorter average
boiling time, higher power, higher heat utilization efficiency and lower fuel consumption
than the two conventional stoves.

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Based on the findings, similar studies may be conducted to further improve the
performance of the biomass cookstove. Integration of other factors which may include
utilization of other types of heating and construction materials, varying the pot skirt to
suit different cooking vessel sizes, varying the thickness of the pot holder for better gaps
between the pot skirt and pot bottom of cooking pot and other design improvements may
be done.

ii

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TABLE OF CONTENTS



Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

INTRODUCTION
Background of the Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
Statement of the Problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
Importance of the Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
Objectives of the Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
Time and Place of the Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4

REVIEW OF RELATED LITERATURE
5

METHODOLOGY
Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
Design criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
Parts and construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10
Testing method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Gathered data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

RESULTS AND DISCUSSION
Comparison between Different Riser Heights of the Improved Cookstove
Average kindling time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
Average boiling time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Heat utilization efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19
Fuel consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
iii

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Comparison between the Improved Biomass Cookstove
and Traditional Cookstoves
Average kindling time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21
Average boiling time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22
Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Heat utilization efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25
Fuel consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27


SUMMARY, CONCLUSION AND RECOMMENDATION

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
29
Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30


LITERATURE CITED 31


APPENDICES
32

43
FIGURES

iv

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INTRODUCTION



Background of the Study



In the past, traditional sources of energy such as fuel wood, charcoal, and dung were
the only sources of energy used for all types of applications. It is only during the last 250
years that fossil fuels such as coal, oil, gas and electricity have emerged as major sources of
energy in most developed countries. However, nearly 75% of the world’s population who
lives in the developing countries continues to depend on the traditional sources of energy for
most of their energy requirements (Scurlock and Hall, 1989). This situation is very evident in
some Asian countries where traditional; sources of energy account for 60-90% of the total
amount of energy consumed.

This dependence on traditional sources of energy for most developing countries is
brought about by the common method of cooking using an open fire. The fire is usually
shielded or surrounded by “three or more stones, bricks, mounds of mud, or lumps of other
incombustible material” (Foley and Moss, 1983). In short, such fires are called “three-stone”
fires, where the stones or surrounding materials act as support for the cooking pot over the
fire. These three-stone fires have continued to be used for cooking and heating purposes,
mainly due to their simplicity. They are easily to build, virtually free, use a range of fuels and
are adapted to different forms quite easily such as placing them on waist-high platforms for
more convenience to the user. Accompanying these features of traditional stoves however, is
the fact that most sources site the fuel-efficiency of conventional stoves as 5 to 10%.
Since nearly three-billion people in the world use traditional stoves to cook their
meals, efforts to improve the efficiency of cookstoves have been increasingly popular in the
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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developing world. Over time, stoves have been developed to overcome problems of the
conventional stoves making way to improved biomass cookstoves. Improved cookstoves are
an attempt to address the negative environmental and social effects of the three rock fire
stove. Improved stoves increase efficiency of fuel consumption, reduce the amount of
pollution released into indoor and outdoor cooking environments, and are designed and built
in various ways, depending on the local conditions. “At their simplest, improved stoves rely
on providing an enclosure for the fire to cut down on the loss of radiant heat and protect it
against the wind. In addition, attention can be given to devising methods of controlling the
upward flow of the combustion gases, so as to increase the transfer of heat to the cooking
pot” (Foley and Moss, 1983).

Statement of the Problem




Most rural households and industries in Asia use wood energy for various purposes.
The Philippines, particularly in the Cordillera region, some households still rely on the three-
rock fire and other conventional stoves for household and institutional cooking. This is
because of various reasons such as availability and accessibility to fuel wood source, cultural
traditions and practices and of its low cost. This is evident; despite the problems associated
with the use of such stoves such as: inefficient energy since customary wood fires are poor at
transferring the released energy into the cooking vessel; continuous deforestation due to
increased amount of wood harvested from the surrounding environment; increasing use of
time for collection of fuel; and deleterious health and environmental effects.
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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With these outlooks on unhealthy and unsustainable conventional cooking methods,
introduction of modern, improved and efficient biomass stoves can alleviate some of the
problems associated with the use of traditional cookstoves.

Importance of the Study




Due to the foreseeable continued use of biomass fuels in the Cordillera region for the
indefinite future, the introduction of locally made improved biomass cookstoves is beneficial.
Improved stoves reduce the demand for biomass fuel and improve living conditions for
populations who currently use three rock fires. The main justifications for improved stoves
are economical, social and environmental-the stove saves time and money for the users. In
urban areas, where people purchase biomass fuel, the payback time for the cost of an
improved stove is short, thus providing extra cash from purchasing less fuel. In rural areas,
more efficient stoves can reduce the time spent collecting fuel for cooking, freeing time for
child care and income-producing activities. Moreover, improved stoves can help moderate
the environmental externalities of over-harvesting trees.

Objectives of the Study


The general objective of the study was to design and develop an improved biomass
cookstove for institutional use.
Specifically, the study aimed to:
1. Evaluate the performance of the improved cookstove using the water-
boiling test;
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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2. Evaluate the power, heat utilization efficiency and fuel consumption of
the improved cookstove;
3. Evaluate performance of the improved cookstove in relation to various
riser heights;
4. Compare performance of the improved cookstove with two traditional
stoves the three-rock fire and metal plate stove in terms of power, heat
utilization efficiency and fuel consumption.

Time and Place of the Study




The study was conducted from January to March 2008 at Benguet State University,
La Trinidad, Benguet.

Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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REVIEW OF RELATED LITERATURE



With the passage of time, woodstoves have undergone numerous design innovations
mainly by the users, in light of their own experiences. These innovations did increase the
efficiency of the stoves to some extent, but health and other hazards remained. Moreover,
despite human evolution and the development which have taken place in stoves and fuel,
most of the estimated 75% of the people who live in developing countries, are still largely
employing the three-stone fire for cooking and using traditional sources of energy such as
fuel wood and other biomass similar to their pre-historic ancestors several thousand years
ago.
In industrial countries, the switch to more efficient stoves took place smoothly as fuel
wood prices increased and stove makers increased efforts to build more efficient models.
This was followed by a transition to cleaner fuels for cooking, such as coal and petroleum-
based fuels. As the availability of and access to petroleum-based fuels began to increase at
the beginning of the twentieth century, many urban households in developing countries
switched to stoves using oil-based products such as kerosene or liquid petroleum gas as fuels,
just like their developed nation counterparts. On the other hand, rural households continued
their dependence on the burning of biomass fuels for their energy requirements. This was
mainly due to weak delivery channels for petroleum-based products and rural people’s
inability to afford these fuels especially compared to biomass resources, which were more
freely available (Barnes et al, 1994).
Nowadays, the motivation for dissemination of improved stoves is much greater from
the national perspective of today’s developing countries, because the population pressure on
the biomass resources base is much higher. As noted before, many of the traditional stoves
Design and Development of an Improved Biomass Cookstove for
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operate with high fuel wood or energy consumption whereas improved cookstoves can
reduce the amount of wood fuel needed to cook. Improved heat transfer efficiency of energy
from the fire to the cooking vessel in improved cookstoves reduce the amount of energy
wasted, thus reducing the amount of wood needed. This improved heat transfer efficiency is
accomplished through design improvements which normally involve the introduction of a
chimney and the incorporation of other critical features such as a pot skirt that creates a
narrow channel forcing hot air and gas to along the bottom and sides of the cooking vessel.

In addition to a desire to rationalize the continuing reliance on biomass fuels, a desire
to prevent or mitigate deforestation also contributed to the growth of improved cookstoves. A
further motivation was that the increasing pressure on biomass resources often results in the
burning of crop residues and dung (commonly done in Asia), thus reducing their return to
maintain the fertility of the soil (Anderson and Fishwick, 1985).

The first improved stoves began to appear in the early 1980’s and were designed by
aid groups such as United Nations Children’s Fund and Cooperative for American Relief
Everywhere-Kenya (Kammen, 1995). The groups applied an elementary exercise of
improving the efficiency of a common metal stove where they were able to reveal an analysis
that the largest loss of heat from the fire is about 50 to 70 percent, and occurs from radiation
and conduction through metal walls.

Better stove designs gradually came about during the mid-1980. At that time, a
number of academics began to publish serious analyses of optimal stove combustion
temperatures and of the insulating properties of the ceramic liner materials. One of the most
notable contributions to enhanced design came through the responses of several women’s
Design and Development of an Improved Biomass Cookstove for
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organizations that had formed around such issues as community health and protection of the
environment.

China has by far the world’s most extensive program with more than 120 million
improved stoves in place- 7 out of 10 rural households own these units (Kammen, 1995). The
Chinese stoves, which burn wood, crop residues and coal, consist of a brick and mortar
construction with a chimney that fits in the central living area of a home. An insulating
material, such as ash and mortar, is packed around the circular cast-iron opening, which
holds a wok.

One of the first improved stoves-the “Magan Chula” introduced in a publication
called “Smokeless Kitchens for the Millions” (Raju, 1953) advocating the health and
convenience benefits of increasing efficiency in the burning of biomass also further
stimulated the promotion of improved cookstoves. The initial wave of improved cookstove
programs focused on the health aspects of such interventions. The general objective was to
uplift the living conditions of the poor in the developing world (Karakezi and Ranja, 1997).
Attention subsequently shifted to the potential for saving biomass fuels and limiting
deforestation. Currently, there is a refocus on the health-related aspects of improved
cookstoves, as the benefits of moving from traditional stoves to improved ones are
increasingly stressed by public health specialists. In addition, factors such as cooking
comfort, convenience, and safety in the use of stoves are starting to get incorporated into
program designs of improved cookstoves.
Overall, the goal of introducing improved biomass cookstoves is to develop more
energy than non-biomass-burning stoves that can help alleviate local pressures on wood
resources, shorten the walking time required to collect fuel wood, reduce cash outlays
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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necessary for purchased fuel wood or charcoal, and diminish the pollution released to the
environment (Barnes et al, 1994).


Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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MATERIALS AND METHODS



Materials




The materials used in the construction of the improved biomass cookstove were: 20.5
centimeters diameter cylinders (empty refrigerant tanks), 56 centimeters diameter cylinder
(empty sodium cyanide tank), gauge # 18 G.I. sheet, 8 mm diameter round bar, 4 mm flat bar
and 63.5 centimeters diameter institutional metal cooking pot.

Tools and equipment used were: hacksaw, portable drill and drill bits, grinder, drill
press, iron sheet scissors, arc-welding machine and welding rods. After the construction,
devices such as the stopwatch, mercury thermometer and weighing balance were used for the
evaluation process.

Design Criteria


a. Easy to Fire


The cookstove could at least be started easily by using little amount of kindling
material. The fire should be developed as fast as possible and should be maintained within
reasonable time period or must boil the water in the shortest possible time.
b. Simple Design

The design must easily be understood to attract possible users to use or produce it.
c. Availability of materials to be used

The device must be made of materials that are locally available.




Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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Parts and Construction




The improved cookstove for institutional use is composed of the following parts:
1. Fuel Magazine
The fuel magazine is the horizontal part of the combustion chamber. It was
made out of gauge #18 G.I. sheets having an area of 18 centimeters by 20.5
centimeters.
a. Air Duct/Vent - The smaller division beneath the fuel shelf where cold air
enters.
b. Fuel Shelf – It is the part where fuel wood is placed for combustion.
2. Riser /Chimney
The chimney is the vertical part of the combustion chamber where the hot air
from the burning fuel wood and the cold air sucked in from outside of the stove mix
to create higher heat energy. This part was constructed using 20.5 centimeters
diameter empty refrigerant tanks.
3. Outer Cylinder
It is the outermost part of the device which serves as a support to the pot skirt.
It was made out of 56 centimeters diameter empty sodium cyanide tank.
4. Pot Holder
This part serves as a support for the cooking vessel and also provides space
between the pot and the pot skirt allowing hot flue gases from the riser/chimney to
exit. It was constructed out of 8 mm diameter round bars.


Design and Development of an Improved Biomass Cookstove for
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5. Pot Skirt
This part of the device was welded to the chimney/riser and to the outer cylinder
following the shape of the cooking vessel to be used. This would increase the surface
contact between the hot fumes and the pot. It was made out of a 63.5 centimeters
diameter institutional metal cooking pot.

Testing Method


a. Fuel Description
The water boiling test used commercially available native alnus wood from
the La Trinidad Public Market, Km. 5 with an approximate length of 46 centimeters
and a triangular shape measuring 3 centimeters on each side.
b. Kindling Material
Just like in an ordinary household practice in the Cordillera region, pieces of
pine wood were used as kindling material.
c. Boiling Pot
The evaluation of the device made use of a 63.5 centimeters diameter
institutional cooking pot.
d. Water Boiling Test

The water-boiling test used was based on the simplified version of the
Ministry of Energy and Mineral Development, “A Comparison of Wood-Burning
Cookstoves for Uganda: Testing and Development” (Emma George, 2002).
The
test
applied
to
the cookstoves consists of two categories. The first
category is the High Power Boiling Test where 6 kilograms of water was heated as
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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12
fast as possible and boiled for 30 minutes to determine the highest power the stoves
are capable of, the efficiency at that power, and the fuel consumption of the stoves.
The second category is the Combined High and Low-Power Boiling Test where 6
kilograms of water were heated to boiling point and simmered for 90 minutes to
determine: the fuel consumption in performing such task, and an efficiency figure for
the stoves.


In the High Power Boiling Test, where the stove was at its initial condition, 5
kilograms of alnus wood was set to fire immediately by 50 grams of the kindling
material. After taking the initial water temperature, the institutional pot without
cover/lid containing 6 kilograms of water was then placed on top of the stove.
Temperature readings were then taken at 5 minute-intervals as the water was set to
boil. Once the water reached the local boiling point, high power was maintained for
30 minutes. Afterwards, the burning wood was extinguished and the water
temperature and weight were recorded quickly. The remaining unburned fuel wood
and the charcoal produced were also weighed separately.


In the Combined High and Low-Power Boiling Test, 5 kilograms of alnus
wood was again set to fire immediately by 50 grams of the kindling material. After
the initial temperature of water was read, the institutional pot containing 6 kilograms
of water (with the pot covered) was then placed on top of the stove. Temperature
readings were again taken at 5 minute intervals as the water was set to a boil at
maximum power. Once the water reached boiling point, power was reduced to the
minimum level required to keep the water simmering. Simmering was maintained for
90 minutes. Afterwards, burning wood was extinguished and the water temperature
Design and Development of an Improved Biomass Cookstove for
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13
and weight were measured quickly. The charcoal and unburned wood were again
weighed separately.


The water-boiling test procedure described was applied to the institutional pot
using the constructed improved cooktove. The same test was also applied to the
traditional tripod stove and metal plate stove.


The power, heat utilization efficiency, and fuel consumption of the cooking
devices were computed using the accumulated data from their respective water-
boiling tests.
e. Measurement of Local Boiling Point
The local boiling point was determined by putting three (3) kilograms of water
in the testing pot and bringing it to a rolling boil. It was made sure that the fire is very
powerful, and the water is furiously boiling. A thermometer was then placed at the
center of the pot, 5 cm above the pot bottom to measure the local boiling temperature.
The highest temperature recorded which was 97o C was determined the local water
boiling point.
f. Determining the Moisture Content


The moisture content of the fuel wood was determined using the Gravimetric
Method. Fuel samples were oven dried at a constant temperature of 110 degrees
Celsius for 12 hours. The moisture content was then computed using the equation:


Moisture content (%) = Fresh weight – Oven dry weight x 100
Oven dry weight







Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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Data Gathered


a. Average kindling time
The average kindling time was determined by observing how long it took the
alnus wood to start burning using 50 grams of pinewood (“saleng”) as kindling
material.
b. Average boiling time
The average boiling time was the time it took for the 6 kilograms of water to
boil.
c. Fuel Consumption
Fuel consumption was the amount of fuel used. It was calculated by mass of
wood burnt away, taking moisture content into account and mass of charcoal
produced.
d. Power of the Stove
Power is (energy transferred)/ (time taken). Power was calculated on the basis
that temperature rise and mass of water boiled away both represent useful energy
transferred to the water. Taking specific heat of water = 4.185 J/g/oC and latent heat
of water = 2.33 Mj/kg.
In equation:

P= (Tf-Ti) 4185Mwi + (Mwi-Mwf) 2.33 x 10 6
t

where:

P=power of the stove

Tf=final water temperature
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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Ti=initial
water
temperature

Mwi=initial mass of water

Mwf=final mass of water
t=time

e. Heat Utilization Efficiency of the stove
Heat Utilization Efficiency is the ratio between the energy input to the stove
(the wood fuel) and the energy actually transferred to the water. The efficiency of the
stove for the High Power Boiling Test was given by:

E= (Tf-Ti) 4185 Mwi + (Mwi-Mwf) 2.33 x 10 6
(Maf-Mai) Evw – Evc Mc



The efficiency of the stove for the Combined High and Low-Power Boiling
Test was given by:



E= (Tf-Ti)4185 Mwi_________


(Maf-Mai) Evw – Evc Mc





The energy value of the fuel wood was computed by the formula:
Evw=
100x20-2.4
(54+M/100)




100+ (M/100)
where:

E=heat utilization efficiency of the stove

Evw=energy value of fuel wood (Mj/kg)

Evc=energy value of charcoal=30 Mj/kg

Tf=final water temperature
Ti=initial
water
temperature

Mwi=initial mass of water

Mwf=final mass of water
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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Maf=final mass of fuel wood

Mai=initial mass of fuel wood

Mc=mass of charcoal formed
M=computed
Moisture
Content of Alnus Wood (13.341%)



In the evaluation of the cookstoves, there were two tests applied namely: without
lid/cover for the institutional pot where the stove was evaluated using the High
Power
Boiling Test; and with lid/cover for the institutional pot where the stove was evaluated using
the Low Power Boiling Test

Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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RESULTS AND DISCUSSIONS



Comparison between Riser Heights of the Improved Biomass Cookstove


Average Kindling Time


Table 1 shows the average kindling time of the improved biomass cookstove at
different riser heights, height 4 of the improved biomass cookstove has the shortest kindling
time of 5.300000 minutes and height 1 has the longest kindling time of 5.455750 minutes.
However, statistical analysis of the data on kindling time shows that there is no significant
difference in the kindling time of the stove regardless of the different heights.

Data on average kindling time of the stove was only recorded during the High Power
Boiling Test since the Low Power Boiling Test was a mere continuation of high power
boiling.

Table 1. Average kindling time of the improved cookstove as affected by different riser
heights (minutes)


MEANS FOR DIFFERENT HEIGHTS


1
2
3
4
Grand Mean
(10cm)
(20cm)
(30cm)
(40cm)
Without lid





5.45575a
5.40525a
5.31125a
5.3a
5.368063
Means with the same letter are not significantly different from each other


Average Boiling Time





Table 2 shows the average boiling time of the improved cookstove to boil 6 kilograms
of water as affected by four (4) different riser heights of the improved stove. High Power
Boiling without lid gave a longer mean boiling time of 17.2341 minutes while Low Power
Design and Development of an Improved Biomass Cookstove for
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Boiling with lid yielded a shorter average boiling time of 13.6403 minutes. These show that
it took 2.87 minutes to boil 1 kilogram of water for the high power boiling test and 2.27
minutes to boil 1 kilogram of water for the low power boiling test.

These differences of recorded boiling time for the two tests were mainly affected by
the presence of a pot cover/lid. High power boiling was done with no cover for the pot of
water while low power boiling was done with a cover for the pot.

Table 2. Average boiling time of the improved cookstove as affected by different riser
heights (minutes)


MEANS FOR DIFFERENT HEIGHTS


1
2
3
4
Grand
(10cm)
(20cm)
(30cm)
(40cm)
Mean
Without





lid
12.4720a
13.6510a
16.8300a
25.9837b
17.2341






With lid
10.7837a
11.3612a
14.1887b
18.2277c
13.6403
Means with the same letter are not significantly different from each other.


Maximum Power Produced




Table 3 shows the maximum power of the improved cookstove during the high power
boiling test as affected by 4 different chimney heights. The average power produced by the
cookstove is 3475.3975 Watts. This shows that the cookstove would provide this maximum
power value, which is utilized when water is below boiling point.

Height 1 of the improved cookstove gave the highest power value of 4003.7153 Watts
and is closely followed by height 2 with a power of 3795.4243 which makes the two heights
belong into one category. These higher power values were contributed by the shorter
chimney height and shorter time which the energy from the burning wood traveled to reach
the pot bottom.
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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19

On the other hand, heights 3 and 4 both gave lower power values of 3232.8029 Watts
and 2869.6474 Watts respectively. These resulted by the longer distance and time which the
energy from the wood traveled to reach the bottom of the pot. Another contributing factor to
this low power values is the energy that has been dissipated by the walls of the stove’s
chimney.

Table 3. Maximum power produced by the improved cookstove as affected by different riser
heights (Watts)


MEANS FOR DIFFERENT HEIGHTS


1
2
3
4
Grand Mean
(10cm)
(20cm)
(30cm)
(40cm)
Without





lid
4003.7153c
3795.4243c
3232.8029b
2869.6474a
3475.3975
Means with the same letter are not significantly different from each other.


Heat Utilization Efficiency




Heat utilization efficiency at High Power Boiling Test: Table 4.1 shows the
cookstove’s efficiency at high power boiling. These figures show the ratio of the energy
actually transferred to the water from the fuel wood. The figures show an inverse relationship
of efficiency and height. These differences may be a result of heat being absorbed by the
walls of the chimney or the stove’s body since higher chimney height means a wider area of
the chimney is absorbing useful heat. Furthermore, taller chimney heights produce less
smoke but are slightly less efficient due to the greater distance between the pot and the
radiant heat of the burning wood while shorter chimney heights produce more smoke but
have greater heat transfer due to the closer proximity of the pot to the radiant wood.


Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

20
Table 4.1. Heat utilization efficiency at high power boiling of the improved cookstove as
affected by different riser heights (%)


MEANS FOR DIFFERENT HEIGHTS


1
2
3
4
Grand Mean
(10cm)
(20cm)
(30cm)
(40cm)
Without





lid
18.4809a
22.2336b
19.0670a
18.2609a
19.5106
Means with the same letter are not significantly different from each other.



Heat utilization efficiency at Low Power Boiling Test: Table 4.2 shows the
cookstove’s efficiency at low power boiling. The computed results for efficiency in this test
are noticeably lower than that of the High Power Boiling Test. This is due to the reason that
only the energy needed to boil the water and maintain it to simmer was taken into account.
However it was observed that efficiency figures from the 4 different heights were similar to
High Power Boiling Test results-inverse relationship of efficiency and chimney height.

Table 4.2. Heat utilization efficiency at low power boiling of the improved biomass
cookstove as affected by different riser heights (%)


MEANS FOR DIFFERENT HEIGHTS


1
2
3
4
Grand Mean
(10cm)
(20cm)
(30cm)
(40cm)
Without





lid
4.4553a
4.4848a
3.5944b
3.3717c
3.97655
Means with the same letter are not significantly different from each other.


Fuel Consumption




Table 5 shows the fuel consumption of the improved stove. It is higher when the pot
is without lid than when it is with a lid because of the energy escaping through the steam,
since energy is given off as water turns to vapor unlike in low power boiling where the
escape of steam is minimized due to a pot cover.
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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21

At High Power and Low Power Boiling, height 2 of the improved cookstove recorded
the least amount of fuel consumed equivalent to 2.85 kilograms and 2.25 kilograms as
compared to the other three heights.

Table 5. Fuel consumption of the improved cookstove as affected by different riser heights
(kilograms)


MEANS FOR DIFFERENT HEIGHTS


1
2
3
4
Grand Mean
(10cm)
(20cm)
(30cm)
(40cm)
Without





lid
3.45a
2.85b
2.95b
3.10b
3.09
With lid





2.31a
2.25a
2.80b
2.97b
2.58
Means with the same letter are not significantly different from each other


Comparison between the Improved Biomass Cookstove and Traditional Stoves


Kindling Time




The improved biomass cookstove registered an average kindling time of 5.40525
minutes (5 min and 25 sec) while the two traditional stoves the three-rock fire and metal plate
stove had 6.70 minutes (6 min and 4 sec) and 5.98 minutes (5 min and 59 sec) of kindling
time respectively. The differences in the time setting of the fuel wood to burn could be the
effect of environmental factor such as wind movement. It was more advantageous for the
improved stove since the fuel wood and kindling material were shielded from the horizontal
wind movement making the fire to be directed upward to the heap of fuel wood on the fuel
magazine, thus, having a shorter time for the fuel to ignite. On the other hand, the three-rock
fire and metal plate stove were exposed to open air causing the fire to bend sideways every
time there is wind movement which resulted to longer kindling times.
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

22
Table 6. Average kindling time of the three stoves (minutes)

R1
R2
R3
MEAN
1.Improved Stove
5.333
5.750
5.133
5.405
2. Three-Rock Fire
6.43
6.72
6.95
6.70
3. Metal Plate Stove
6.19
6.45
5.30
5.98


Figure 1. Comparison on the average kindling time of the three stoves (minutes)


8
i
n) 7
6.7
m
e
( 6
5.9
m
5.405
5
i
ng Ti 4
i
ndl 3
K 2
1
v
e
r
a
ge
A 0
1
2
3
Stoves

Boiling Time




Tables 7 and 8 show the recorded boiling time of 6 kilograms of water for the
different cookstoves. Boiling time was determined using the High Power Boiling Test
(without pot cover/lid) and Low Power Boiling Test (with pot cover/lid).

The Low Power Boiling Test on the cookstoves was able to yield shorter boiling
times because of the presence of a lid that prevented the escape of heat from the water, unlike
in the High Power Boiling Test where the heat freely escaped into the open air since there
was no pot cover causing more time to achieve the amount of energy needed for the water to
boil.
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

23

The improved cookstove was able to boil 6 kilograms of water at High Power Boiling
in 13.651 minutes and 11.3613 minutes if provided with a lid (Low Power Boiling).
Comparing these test results of the improved cookstove with the two conventional stoves, it
is evident that the improved stove made the 6 kilograms of water to boil faster in both tests
than the traditional stoves. These figures were affected by the ability of the stoves to transfer
the heat produced by the fuel to the water.

Table 7. Average boiling time for the high power boiling test of the three stoves (minutes)

R1
R2
R3
MEAN
1. Improved Stove
12.083
14.770
14.100
13.651
2. Three-Rock Fire
25.000
20.433
26.030
23.821
3. Metal Plate Stove
34.750
28.25
32.10
31.7


Table 8. Average boiling time for the low power boiling test of the three stoves (minutes)

R1
R2
R3
MEAN
1. Improved Stove
10.417
12.617
11.050
11.361
2. Three-Rock Fire
20.167
19.500
17.670
19.112
3. Metal Plate Stove
19.417
21.917
22.733
21.356


















Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

24
Figure 2. Comparison on the average boiling time of the three stoves (minutes)

35
)
31.7
in 30
m
e
( 25
23.821
im
21.356
T 20
g
19.112
Without lid
ilin 15
With lid
o
13.651
11.361
e
B 10
5
v
e
r
a
g
A
0
1
2
3
Stoves


Power




Power refers to the ability of the stove to transfer the energy from the fuel wood to
the water in relation to the time taken in doing the task.

The improved stove registered a power value of 3795.4243 Watts which means that it
was able to direct 227.73 KJ of heat energy to the water in a span of 1 minute. Table 9 shows
the two conventional stoves that displayed lower power values. The improved stove has a
shorter boiling time than the two traditional stoves since the greater power value a stove has,
the shorter the time it will take the stove to transfer heat to the cooking vessel.

The higher power value of the improved stove is mainly due to its designed features.
Its combustion chamber is enclosed, preventing the escape of heat to the open air. The
chimney provides an area for the hot air to mix well with oxygen from the air vent of the
cookstove producing more heat energy and velocity. An added feature of the improved
cookstove is the pot skirt which allows the hot fumes to get in direct contact to the cooking
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

25
vessel causing a more efficient transfer of heat energy. On the other hand, lower power
values were recorded for the three-rock fire and metal plate stove due to the smaller area of
cooking vessel in direct contact to the fire and the loss of useful heat to open air.

Table 9. Maximum power produced by the three stoves (Watts)

R1
R2
R3
MEAN
1. Improved Stove
3910.9815
3862.4060
3612.8855
3795.4243
2. Three-Rock Fire
2603.3856
2744.1685
3076.4046
2807.9862
3. Metal Plate Stove
1952.3192
2049.1001
2188.0730
2063.1641


Figure 3. Comparison on maximum power value of the three stoves (Watts)

4000
3795.4243
3500
3000
)
2807.9862
2500
a
tts
2063.1641
2000
e
r
(W
w 1500
Po 1000
500
0
1
2
3
Stoves


Heat Utilization Efficiency




The heat utilization efficiency of a stove is computed as the amount of energy used by
the water over the amount of energy produced by the fuel wood. Its purpose is to show how
much of the heat energy is actually used since not all of it is utilized effectively; some were
lost during the transfer.
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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26
Table 10 shows the efficiencies of the different cookstoves. The improved cookstove
was able to register an efficiency of 22.2337%, about 9% and 11% higher than the three rock
fire and metal plate stove respectively. This means the stove was able to transfer 22.2337%
of the heat energy produced to the water. Although some of the heat was absorbed by the
stove’s metal walls, this lost heat energy was much lesser as compared to the amount of heat
lost to the open air by the traditional stoves. The more efficient the stove, the higher is the
saving for fuel wood.

Table 10. Heat utilization efficiencies of the different cookstoves (%)

R1
R2
R3
MEAN
1. Improved Stove
22.8280
20.9619
22.9111
22.2337
2. 3-Rock Fire
12.0935
12.6180
12.7592
12.4902
3. Metal Plate Stove
10.7816
11.6698
11.9581
11.4698


Figure 4. Comparison on heat utilization efficiencies of the three stoves (%)

25
22.2337
c
y
n 20
ie
f
f
ic
15
E
n
12.4902
11.4698
a
t
io
10
t
iliz
5
e
a
t
U
H
0
1
2
3
Stoves





Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

27
Fuel Consumption




Fuel consumption refers to the amount of fuel used by the stove. Tables 11 and 12
show the fuel consumptions of the stoves during the tests. During the High Power Boiling
Test where no lid was used, the stoves consumed higher amount of fuel wood for the reason
that the energy being lost to the air by the water was needed to be replaced for the water to
raise and maintain its temperature. The presence of the lid during the Low Power Boiling
Test trapped and prevented the heat from escaping the cooking vessel, resulting to a lesser
amount of fuel needed to raise and maintain the temperature of the water.

Based on the test results, the Improved Stove registered lower amount of fuel used for
both tests compared to the conventional stoves. This advantage was due to its higher
efficiency. The Three-Rock Fire consumed more fuel since much of the heat was lost to the
open air instead of being transferred to the cooking vessel. The Metal Plate Stove on the
other hand had more advantage over the Three Rock Fire since two of its sides were shielded;
however, the ability to transfer heat was lessened due to the lesser pot area exposed to the
radiant fire.

Table 11. Fuel consumption of the cookstoves for the high power boiling test (kilograms)

R1
R2
R3
MEAN
1. Improved Stove
2.75
3.10
2.70
2.85
2. 3-Rock Fire
4.25
4.15
4.47
4.29
3. Metal Plate Stove
4.22
3.80
4.02
4.01







Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

28

Table 12. Fuel consumption of the cookstoves for the low power boiling test (kilograms)

R1
R2
R3
MEAN
1. Improved Stove
2.23
2.40
2.13
2.25
2. 3-Rock Fire
2.43
2.62
2.33
2.46
3. Metal Plate Stove
3.35
3.68
3.20
3.41


Figure 5. Comparison on the fuel consumption of the three stoves

5
4.5
4.29
4
4.01
k
g)
3.5
3.41
i
on (
3
pt
2.85
Without lid
2.5
um
2.46
2.25
with lid
2
ons 1.5
l
C
1
Fue 0.5
0
1
2
3
Stoves



Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

SUMMARY, CONCLUSIONS AND RECOMMENDATIONS



Summary


The improved biomass cookstove was constructed and evaluated from January to
March 2008. It was made out of an empty sodium cyanide tank, a gauge of #18 G.I. sheet and
empty refrigerant tanks.

The water boiling test which is composed of the High Power Boiling Test and Low
Power Boiling Test was used in the evaluation of the power, efficiency and fuel consumption
of the device.

Results showed that the improved biomass cookstove has a better stove performance
at height 2 or a riser height of 20 centimeters as compared to height 1 or riser height of 10
centimeters, height 3 or riser height of 30 centimeters and height 4 or riser height of 40
centimeters.

Comparing these test results with the three-rock fire and metal plate stove, the
improved biomass cookstove had a higher power value of 3795.42 Watts than the three-rock
fire which registered a power value of 2807.99 Watts and the metal plate stove having a
power value of 2063.16 Watts.

The improved cookstove’s efficiency was 22.23% which was also way higher than
the three-rock fire which had an efficiency of 12.49% and the metal plate stove with an
efficiency of 11.47%.

Fuel consumption for the improved cookstove was much lesser than the two
traditional stoves. It consumed 44.83 MJ or 2.40 kilograms of alnus wood at High Power
Boiling Test and 40.88 MJ or 2.19 kilograms wood at Low Power Boiling Test. On the other
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

30
hand, the three-rock fire and metal plate stove consumed 68.02 MJ or 3.64 kilograms of
wood and 66.63 MJ or 3.57 kilograms of fuel wood at High Power Boiling and 43.04 MJ or
2.31 kilograms wood and 59.97 MJ or 3.21 kilograms wood at Low Power Boiling. Fuel
consumption for the improved cookstove is much lesser than the two traditional stoves.

Conclusion


Based on the findings, the following conclusions were drawn:
1. The improved biomass cookstove is more efficient at a riser height of 20
centimeters.
2. The improved biomass cookstove had higher power and efficiency values than the
three-rock fire and metal plate stove.
3. The improved biomass cookstove consumed lesser fuel than the two conventional
stoves.

Recommendations




Based on the findings and conclusion, the following recommendations are provided.
1. Integration of other factors such as utilization of other types of heating and
construction materials, adjustable pot skirt to suit different cooking vessel sizes,
varied thickness of the pot holder for better gaps between the pot skirt and pot
bottom of cooking pot and other design improvements should be integrated
2. .Similar studies may be conducted to further improve the performance of the
biomass cookstove.
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

LITERATURE CITED


OGNAYON, D.S and , B.M II TANGGANA. 2007. Fabrication and Evaluation of a

Biomass Stove for Cooking and Water Heating. Unpublished Undergraduate Thesis,

Benguet State University, La Trinidad, Benguet.

BARNES, D F, OPENSHAW, K, K.R. SMITH, R. VAN DER PLAS: 1993. The Design

and Diffusion of Improved Cooking Stoves. The World Bank Research Observer;
Washington.

GEORGE, E. 2002. A Comparison of Wood-Burning Cookstoves for Uganda: Testing and

Development. The Ministry of Energy and Mineral Development.

KAMMEN, D. M. 1995. Cookstoves for the Developing World, Scientific American.

KARAKEZI, S. and T. RANJA. 1997.Renewable Energy Technologies in Africa, Zed
Books Ltd. London, New Jersey.

REGIONAL WOOD ENERGY DEVELOPMENT PROGRAMME (RWEDP).
Improved Solid Biomass Burning Cookstsoves: A Development Manual. Field
Document No.44. Available online: http://www.rwedp.org/acrobat/fd44.pdf

FAO-REGIONAL WOOD ENERGY DEVELOPMENT PROGRAMME (RWEDP).
Wood Energy conservation. Available online: http://www.webmaster@rwedp.org

FOLEY, G. and P. MOSS. 1983. Improved Cooking Stoves in Developing Countries.
Earthscan, International Institute for Environment and Development, Energy
Information Programme, Technical Report No. 2.


Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

APPENDIX


Appendix Table 1. Result of the Water Boiling Test for the Improved Stove



Kindling
Time
Weight Weight of
Weight
Raise in
Time
to Boil
of
Water
of
Temperature
(min)
(min)
Wood Evaporated Charcoal
(o C)
Used
(kg)
Produced
(kg)
(kg)
Test 1







(High
Power)
H1
R1 5.667
11.583 3.2 3.7 0.29
76
(10cm)
R2
5.167
12.300
3.5 3.4 0.30 75
















R3
5.533
13.533
3.65 3.6 0.41 74.5
H2







(20 cm)
R1
.333
12.083
2.75
3.43
0.27
75








R2
5.750
14.77
3.1
3.65
0.28
74.5








R3
5.133
14.1
2.7
3.3
0.29
74.5
H3







(30 cm)
R1
5.300
18.74
3.15
3.3
0.23
75








R2
5.417
13.883
2.8
2.9
0.26
75.5








R3
5.217
17.867
2.9
3.05
0.25
76
H4







(40 cm)
R1
5.267
23.617
3.5
3.6
0.219
76








R2
5.333
26.167
2.95
3.1
0.23
76








R3
5.300
19.917
2.85
2.65 0.23 76
Test 2







(Low
Power)
H1







(10cm)
R1
8.817
2.31 0.074 74









Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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33



R2
11.117
2.42 0.050 72









R3
12.417
2.19 0.051 73.5








H2
R1
10.417
2.23 0.035 74
(20 cm)








R2
16.617
2.4
0.045
72








R3
11.05
2.13 0.040 72.5
H3







(30 cm)
R1
16.783
2.41
0.036
72








R2
12.733
2.89 0.041 72








R3
13.050
3.1 0.031 73.5
H4







(40 cm)
R1
20.200
2.64
0.029
72.5








R2
16.83
3.03 0.035 72
R3
17.600
3.25 0.026 74



























Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

34
Appendix Table 2. Results of the Water Boiling Test for the Traditional Stoves



Kindling
Time
Weight Weight of
Weight
Raise in
Time
to Boil
of
Water
of
Temperature
(min)
(min)
Wood Evaporated Charcoal
(o C)
Used
(kg)
Produced
(kg)
(kg)
Test 1







(High
Power)
Three-







rock
R1
6.43
25.00
4.25
2.6
0.45
76
fire








R2
6.72
20.433
4.15
2.75
0.39
75.5








R3
6.95
26.03
4.47 3.15 0.37 75.5
Metal







Plate
R1
6.19
34.750
4.215
2.447
0.279
75
Stove








R2
6.45
28.25
3.8 2.26 0.32 75.5








R3
5.30
32.10
4.02 2.68 0.23 76
Test 2







(Low
Power)
Three-







Rock
R1
20.167
2.43
0.095
71.5
Fire








R2
19.5
2.62
0.087
72








R3
17.67
2.33
0.108
72.5
Metal







Plate
R1
19.417
3.35
0.127
71
Stove








R2
21.917
3.68 0.150 71








R3
22.733
3.2 0.095 72



Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

35
Appendix Table 3. Analysis of Variance on the Average Kindling Time of the Improved
Stove as Affected by the Different Chimney Heights


Descriptives
Power
95% Confidence Interval for
Mean
N
Mean
Std. Deviation
Std. Error
Lower Bound
Upper Bound
Minimum
Maximum
10 cm
4
4003.715
155.3164311
77.65822
3756.572274
4250.858476
3863.377
4220.218
20 cm
4
3795.424
130.5889583
65.29448
3587.628151
4003.220499
3612.886
3910.982
30 cm
4
3232.803
66.6441076
33.32205
3126.757278
3338.848572
3138.857
3286.316
40 cm
4
2869.647
234.0529689
117.0265
2497.216972
3242.077978
2698.767
3200.589
Total
16
3475.398
485.1450204
121.2863
3216.881992
3733.913058
2698.767
4220.218




ANOVA Sum
of
df Mean F Sig.
Squares
Square
Kindling Time
Between
.068 3 .023 .764ns .536
Groups
Within
.355 12 .030

Groups
Total
.422
15



ns Not Significant



Height
N
Subset for alpha = .05

1
40 cm
4
5.300000
30 cm
4
5.311250
20 cm
4
5.405250
10 cm
4
5.455750
Sig.
.258
Means for groups in homogeneous subsets are displayed.
a Uses Harmonic Mean Sample Size = 4.000.







Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

36
Appendix Table 4. Analysis of Variance on the Average Boiling Time of the Improved
Stove as Affected by Different Chimney Heights (High Power Boiling Test)


Descriptives
Time to Boil
95% Confidence Interval for
Mean
N
Mean
Std. Deviation Std. Error Lower Bound Upper Bound Minimum Maximum
10 cm
4 12.472000
.8053211 .4026605
11.190554
13.753446
11.5830
13.5330
20 cm
4 13.651000
1.1419845 .5709923
11.833848
15.468152
12.0830
14.7700
30 cm
4 16.830000
2.1141017 1.0570509
13.465992
20.194008
13.8830
18.7400
40 cm
4 25.983750
7.6383499 3.8191749
13.829431
38.138069
19.9170
37.1670
Total
16 17.234188
6.5485009 1.6371252
13.744738
20.723637
11.5830
37.1670





ANOVA Sum
of
df Mean F Sig.
Squares
Square
Time to Boil
Between
448.943 3 149.648
9.242**
.002
Groups
Within
194.299 12 16.192

Groups
Total
643.243
15



**Highly Significant



Height
N
Subset for alpha = .05
1 2
10 cm
4
12.472000

20 cm
4
13.651000

30 cm
4
16.830000

40 cm
4

25.983750
Sig.
.170 1.000
Means for groups in homogeneous subsets are displayed.
a Uses Harmonic Mean Sample Size = 4.000.






Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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37
Appendix Table 5. Analysis of Variance on the Average Boiling Time of the Improved Stove
as Affected by Different Chimney Heights (Low Power Boiling Test)


Descriptives
Boiling Time (combined high and low)
95% Confidence Interval for
Mean
N
Mean
Std. Deviation Std. Error Lower Bound Upper Bound Minimum Maximum
10 cm
4 10.783750
1.4884742 .7442371
8.415255
13.152245
8.8170
12.4170
20 cm
4 11.361250
.9247329 .4623664
9.889794
12.832706
10.4170
12.6170
30 cm
4 14.188750
1.8390299 .9195149
11.262443
17.115057
12.7330
16.7830
40 cm
4 18.227750
1.4250372 .7125186
15.960198
20.495302
16.8830
20.2000
Total
16 13.640375
3.3090594 .8272649
11.877102
15.403648
8.8170
20.2000





ANOVA Sum
of
df Mean F Sig.
Squares
Square
Boiling Time
Between
138.798 3 46.266
21.815**
.000
(combined high and
Groups
low)
Within
25.450 12 2.121

Groups
Total
164.248
15



**Highly Significant



Height
N
Subset for alpha = .05
1 2
10 cm
4
12.472000

20 cm
4
13.651000

30 cm
4
16.830000

40 cm
4

25.983750
Sig.
.170 1.000
Means for groups in homogeneous subsets are displayed.
a Uses Harmonic Mean Sample Size = 4.000.





Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

38
Appendix Table 6.Analysis of Variance on the Power of the Improved Stove as Affected by
Different Chimney Heights (High Power Boiling Test)


Descriptives
Power
95% Confidence Interval for
Mean
N
Mean
Std. Deviation
Std. Error
Lower Bound
Upper Bound
Minimum
Maximum
10 cm
4
4003.715
155.3164311
77.65822
3756.572274
4250.858476
3863.377
4220.218
20 cm
4
3795.424
130.5889583
65.29448
3587.628151
4003.220499
3612.886
3910.982
30 cm
4
3232.803
66.6441076
33.32205
3126.757278
3338.848572
3138.857
3286.316
40 cm
4
2869.647
234.0529689
117.0265
2497.216972
3242.077978
2698.767
3200.589
Total
16
3475.398
485.1450204
121.2863
3216.881992
3733.913058
2698.767
4220.218





ANOVA Sum
of
df Mean F Sig.
Squares
Square
Power Between
3229288
3 1076429.
42.886** .000
Groups
.665
555
Within
301196.
12 25099.72


Groups
697
5
Total
3530485
15
.363
**Highly Significant



Height
N
Subset for alpha = .05
1 2 3
40 cm
4
2869.647475


30
cm 4
3232.802925
20 cm
4


3795.424325
10 cm
4


4003.715375
Sig. 1.000 1.000 .088
Means for groups in homogeneous subsets are displayed.
a Uses Harmonic Mean Sample Size = 4.000







Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

39
Appendix Table 7. Analysis of Variance on the Efficiency of the Improved Stove as Affected
by Different Chimney Heights (High Power Boiling Test)

Descriptives
Effeciency
95% Confidence Interval for
Mean
N
Mean
Std. Deviation Std. Error Lower Bound Upper Bound Minimum Maximum
10 cm
4 18.480925
1.5128140 .7564070
16.073700
20.888150
17.3957
20.6203
20 cm
4 22.233650
.8998894 .4499447
20.801725
23.665575
20.9619
22.9110
30 cm
4 19.067025
.4512003 .2256002
18.349065
19.784985
18.4332
19.4477
40 cm
4 18.260900
.6187002 .3093501
17.276410
19.245390
17.4476
18.9470
Total
16 19.510625
1.8617071 .4654268
18.518591
20.502659
17.3957
22.9110





ANOVA Sum
of
df Mean F Sig.
Squares
Square
Efficiency Between
40.935 3 13.645
14.812**
.000
Groups
Within
11.054 12 .921


Groups
Total
51.989
15



**Highly Significant




Height
N
Subset for alpha = .05
1 2
40 cm
4
18.260900

10 cm
4
18.480925

30 cm
4
19.067025

20 cm
4

22.233650
Sig.
.280 1.000
Means for groups in homogeneous subsets are displayed.
a Uses Harmonic Mean Sample Size = 4.000.





Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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40
Appendix Table 8. Analysis of Variance on the Efficiency of the Improved Stove as
Affected by Different Chimney Heights (Low Power Boiling Test)

Descriptives
Effeciency (combined (high and low)
95% Confidence Interval for
Mean
N
Mean
Std. Deviation
Std. Error
Lower Bound
Upper Bound
Minimum
Maximum
10 cm
4 10.783750
1.4884742
.7442371
8.415255
13.152245
8.8170
12.4170
20 cm
4 11.361250
.9247329
.4623664
9.889794
12.832706
10.4170
12.6170
30 cm
4 14.188750
1.8390299
.9195149
11.262443
17.115057
12.7330
16.7830
40 cm
4 18.477750
1.5102641
.7551320
16.074583
20.880917
16.8830
20.2000
Total
16 13.702875
3.4094072
.8523518
11.886130
15.519620
8.8170
20.2000




ANOVA Sum
of
df Mean F Sig.
Squares
Square
Efficiency
Between
48.160 3 49.387
2.619**
.000
(combined (high
Groups
and low)
Within
6.201 12 2.183

Groups
Total
74.361
15



**Highly Significant



Height
N
Subset for alpha = .05
1 2 3
10 cm
4
4.4553


20 cm
4
4.4848


30 cm
4

3.5944

40 cm
4


3.3717
Sig. .591 1.000 1.000
Means for groups in homogeneous subsets are displayed.
a Uses Harmonic Mean Sample Size = 4.000.








Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

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41
Appendix Table 9. Analysis of Variance on the Fuel Consumption of the Improved Stove as
Affected by Different Chimney Heights (High Power Boiling Test)

Descriptives
Fuel Consumption
95% Confidence Interval for
Mean
N
Mean
Std. Deviation Std. Error Lower Bound Upper Bound Minimum Maximum
10 cm
4 58.222200
6.7322753 3.3661376
47.509648
68.934752
51.0632
67.2374
20 cm
4 44.826600
3.3603379 .6801690
39.479553
50.173647
41.7252
49.4956
30 cm
4 47.694200
3.1227458 .5613729
42.725215
52.663185
44.4928
51.9294
40 cm
4 50.171800
4.1873406 2.0936703
43.508807
56.834793
46.3266
55.9946
Total
16 50.228700
6.5814128 .6453532
46.721713
53.735687
41.7252
67.2374




ANOVA Sum
of
df Mean F Sig.
Squares
Square
Fuel Consumption
Between
398.023 3 132.674
6.325**
.008
Groups
Within
251.702 12 20.975


Groups
Total
649.725
15



**Highly Significant



Height
N
Subset for alpha = .05
1 2
20 cm
4
44.826600

30 cm
4
47.694200

40 cm
4
50.171800

10 cm
4

58.222200
Sig. .142 1.000
Means for groups in homogeneous subsets are displayed.
a Uses Harmonic Mean Sample Size = 4.000.






Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

42
Appendix Table 10. Analysis of Variance on the Fuel Consumption of the Improved Stove as
Affected by Different Chimney Heights (Low Power Boiling Test)


Descriptives
Fuel Consumption (combined high and low)
95% Confidence Interval for
Mean
N
Mean
Std. Deviation Std. Error Lower Bound Upper Bound Minimum
Maximum
10 cm
4 41.329300
1.7892553
.8946277
38.482195
44.176405
39.3704
43.6959
20 cm
4 40.883283
2.0075501 1.0037750
37.688822
44.077743
38.5799
43.4724
30 cm
4 51.462800
5.4540164 2.7270082
42.784243
60.141357
43.9292
56.9656
40 cm
4 54.629975
4.7314677 2.3657338
47.101154
62.158796
48.4346
59.9170
Total
16 47.076339
7.1592261 1.7898065
43.261457
50.891222
38.5799
59.9170




ANOVA Sum
of
df Mean F Sig.
Squares
Square
Fuel Consumption
Between
590.723 3 196.908
13.268**
.000
(combined high
Groups
and low)
Within
178.094 12 14.841


Groups
Total
768.818
15



**Highly Significant



Height
N
Subset for alpha = .05
1 2




20 cm
4
40.883283
10 cm
4
41.329300

30 cm
4

51.462800
40 cm
4

54.629975
Sig.
.873 .268
Means for groups in homogeneous subsets are displayed.
a Uses Harmonic Mean Sample Size = 4.000.


Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

FIGURES




Figure 6. Weighing the fuel wood


Figure 7. The fuel wood and kindling material used

Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

44


Figure 8. Weighing the water for the water boiling test
























Figure 9. The fire at chimney height 1 of the improved stove
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

45

Figure 10. The fire at chimney height 2 of the improved stove


Figure 11. The fire at chimney height 3 of the improved stove
Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

46

Figure 12. The fire at chimney height 4 of the improved stove


Figure 13. High Power Boiling Test (height 1)

Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

47

Figure 14. Low Power Boiling Test (height !)





















Figure 15. High Power Boiling Test (3-rock fire)

Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

48

Figure 16. High Power Boiling (metal plate stove)


Figure 17. Low Power Boiling Test (metal plate stove)



Design and Development of an Improved Biomass Cookstove for
Institutional Use / Jerry D. Batcagan and Albanese W. Felwa.2008

---

Document Outline

• Design and Development of an Improved Biomass Cookstove for Institutional Use
  • BIBLIOGRAPHY
  • ABSTRACT
  • TABLE OF CONTENTS
  • INTRODUCTION
    • Background of the Study
    • Statement of the Problem
    • Importance of the Study
    • Objectives of the Study
    • Time and Place of the Study
  • REVIEW OF RELATED LITERATURE
  • MATERIALS AND METHODS
    • Materials
    • Design Criteria
    • Parts and Construction
    • Testing Method
    • Data Gathered
  • RESULTS AND DISCUSSIONS
    • Comparison between Riser Heights of the Improved Biomass Cookstove
      • Average Kindling Time
      • Average Boiling Time
      • Maximum Power Produced
      • Heat Utilization Efficiency
      • Fuel Consumption
    • Comparison between the Improved Biomass Cookstove and Traditional Stoves
      • Kindling Time
      • Boiling Time
      • Power
      • Heat Utilization Efficiency
      • Fuel Consumption
  • SUMMARY, CONCLUSIONS AND RECOMMENDATIONS
    • Summary
    • Conclusion
    • Recommendations
  • LITERATURE CITED
  • APPENDIX
  • FIGURES

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