used several years data available on the websites of NGOs and institutions
to achieve our projections and our solar cooking projects. For
all countries of the Sahel environment ministries are almost all identical
- The wood is 90% the only energy source used by families.
Over the past 10 years:
- The population grew by 35 % to 50% in each country
- wood energy applications are becoming increasingly important
- The desert areas are constantly expanding
- The price of wood has increased by 30% to 50% depending
on the region
figures project us towards an important energy crisis that will occur
in all countries of the Sahel.
conducted with associations Project Sur
la Piste and Codegaz
we conducted studies and projections on the development of solar cooking.
We followed every day more than 100 families in Burkina Faso distributed
in eight different areas. These studies have allowed us to make databases
on the habits of users of solar cookers for their energy needs and their
Energy took care of all the processing of these databases. More
than 50,000 data were processed, analyzed and synthesized.
key figures obtained by this study in 2012 - 2013 in Burkina Faso:
FOR WOOD KG PER DAY PER PERSON FOR COOKING:
In many reports the numbers are very different needs for
Kilos of wood per day and per person. We must be very careful
on the figures announced. In our study needs can vary from
simple to double depending on the assessment of respondents. One
explanation could be confusion between the needs kg of wood for cooking
and wood needs for all family activities. (Meals, activities,
food processing, dyeing, cleaning tools, etc..)
The figures reported in the reports are national averages
including preparation of meals but also craft, commercial and industrial
activities ... It is common to find wooden figures need
more than 1.5 kg per day per person.
Our studies focus exclusively on the needs kg of wood for
cooking and mainly operates in rural areas. Our
estimates range between 0 75 kg and 0.9 kg of wood per day per person
depending on season and region. needs wood energy
for cooking would therefore 328kg of wood per person per year for an
average of 0.9 kg per day . If this figure by the number
of inhabitants of Burkina Faso, 17 million is multiplied, we can deduce
that more than 5.5 million tons of wood are burned each year to cook
OF DAYS FOR USING A SOLAR COOKER IN BURKINA FASO 2012-2013
Even in the heart of West Africa, it is not possible to
cook with a solar cooker all day and any what time. A solar
cooker is a complementary alternative energy.
Quite simply it is not possible to cook in the evening
or at night. It is not possible to cook the days of cloud,
rain or harmattan. Our average show that over a year it
is possible to use a solar cooker 65% of the time is about
230 days a year.
OF WOOD SAVED BY SOLAR COOKER
The number of kg of wood that can be saved per year with
a solar cooker is more difficult to treat since it will depend on the
actual use of the solar cooker. With the same solar cooker
and over the same period, a family of six people using it only for meals
will not save the same amount of wood a family of 10 people using the
cooker for these meals and activities sale or processing. When
talking about saving wood solar cooker must therefore know the context
in which the solar cookers were used.
During our study we found that the average number of families
using the cooker was 6 people.
Our statements newspapers have allowed us to project an
average of 0.75 kg of wood per day and per person saved to prepare meals
with a solar cooker and a thermos Cart (Bitam Toré).
For a solar cooker and Bitam Toré used only for meal preparation,
we can project the economy of
one ton of wood per year per family of 6.
calculation is as follows:
0.75 kg x 6 people * 230 days = 1035 kg of wood
This figure may represent up to 65% less wood per year
In the case of income-generating activity or community
group we can achieve much higher percentages up to 80% savings. Some
activities such as dyes can be made at any time of the
day and concentrated only on sunny days. FCFA
SAVED It is important to know the financial savings
that can make a solar cooker in a family. This allows to
make projections on the flow capacity of solar cookers. By
the micro-credit system a solar cooker can be completely self-financed.
However it is difficult to project a figure. The
criteria are many and important differences. Depending
on the geographic area the price of wood is very different. North
of the Sahel timber prices can be twice more expensive than in the south.
In cities the price of wood is higher than in the countryside.
Depending on the season and facilities supply timber prices
also vary greatly. All families do not buy wood regularly,
some will look directly into the bush whenever possible. All
these variations complicate projections saving wood. In
our studies we showed an average of 500 FCFA for a 10kg bundle of wood.
In some areas the price of wood has doubled over the last
10 years. To determine the achievable cost savings with
a solar cooker we project a broad range depending on the situation from
50,000 FCFA to 100,000 FCFA savings
per year for a family of 6 people and solar cooker.
CO2 SAVED BY SOLAR COOKER
With the aim to set up a carbon credit we need to project
the CO2 savings that can help make the use of solar cookers. The
documents of the National Organization of Forestry and Environment Ministries
and energy we can find equivalences Kg wood / carbon / CO2.
Equivalencies are as follows: 1 kg of dry wood produce
1.4 kg of CO2 during its combustion. So for a family of
six people in Burkina Faso it is possible to save 1.4
tons of CO2 per year and cooker.
It might also be interesting to calculate the number of
CO2 produced by the cutting and transporting 5.5 million tons of wood
each year to cities and villages ...
NEEDS IN WATTS
We studied the energy that powers the family had at their
disposal with traditional homes. The ownership of an energy
alternative is easier if it is not a constraint or a decrease in the
current comfort. With some calculations (see "Calculating
the power of solar cookers") we determined the wattage of homes used
by families. For families of 6 to 10 people families generally
have at their disposal the powers of 1000
to 1500 Watts with their wood burning
fireplace. To help ownership of solar cooking is relevant
to propose solar cookers are as close as possible to these powers.
In case families would have no other alternative, solar
cookers same less powerful would be used despite the change of habit
that require cooking.
Families use between 2 and 3 am their homes to prepare
meals per day which is a need of about 2.5
kWh per day per family of 6 . A solar
cooker 1000w for the best periods of sunshine can give up 6kWh day.
OF THE POWER OF SOLAR COOKER
There are several ways to calculate the power of a home
or a heat source. We can use these formulas for solar cookers.
Theoretically there is 1000 watts per square meter of sunshine,
but the factors of restitution of this power is much more complex. A
solar cooker with an area of 1m2 never restore 1000 Watts. The
quality of the film mirrors the accuracy of the concentration, the opening
of the parabola are very important factors for the return of power.
Relatively simple tests exist to calculate the power of
a solar cooker. The most widely used method with water
power P is equal to the heated M x C x specific heat the temperature
of the final water mass TF - the initial temperature TI, divided by
the duration D seconds.
= (MXC) x (TF-TI) / D
solar cooker that is boil 3 liters of water at 20 ° to the origin (specific
heat of water is 4180) in an aluminum pot 1.5kg (specific heat of aluminum
850) in 15 minutes ( 900 seconds) will have a capacity of about 1200
x 4180 + 1.5 x 850) x (100-20) / 900 = 1228
used this method for testing solar cookers is a reliable and relatively
easy to implement in accordance with the same protocol and the same
Other techniques exist, it is possible to measure the amount
of evaporated water for a given time in order to calculate the power
of a stove. The method seems a bit more complex to make,
but it allows to compare the results and performance.
A boiling, the water temperature is constant, the container
also. The energy provided by the cooker no longer serves
to raise the temperature but to vaporize the water. M1
calling an initial mass of water to the boiling temperature of the mass
M2 after a duration t bp, H the enthalpy of vaporization of water (2
260 kJ.kg-1). The power of the cooker can be obtained by:
P H = (M1-M2) / t
OF PRODUCTION OF SOLAR COOKER
cookers remain inexpensive to manufacture, however all
equipment materials can not be found. locally
reflectors film or aluminum plates that allow the reflection
of sunlight are complex to manufacture materials. They
are often three-component or four-component that can not be produced
using traditional or local.
Some solar cookers use glass tubes with walls and vacuum
coated aluminum nitride, it is also difficult to manufacture these parts
To achieve solar concentration, satellite antennas steel
very large sizes can be used. In this case the local manufacturing
and small amounts will be almost impossible. It will necessarily
be importing these parables.
Certain parts often require to be imported from China or
Europe to manufacture in Africa.
manufacturing costs are highly uncertain based on the quantities
and import product costs but also on the basis of expected solar cookers
requirements. We can consider the cost of €
75 150 € to achieve an efficient
solar cooker Burkina Faso can be used daily by a family Sahel and this
over several years.
We have in our projects involve different products to allow
optimization of wood savings. The most interesting formula
is a combination of three complementary products. A
solar cooker, a Bitam Toré and cooker Wood Peeler
(EPC or home improvement). We thus arrive at more than
75% of wood per year per person savings for cooking meals. We
estimate a 30% savings possible through the use of an EPC.
cooking when used with cookers with a very specific focal point can
be just as dangerous as cooking over a wood fire or gas. The
temperature at the focal point can exceed 500 ° and burns or fires can
happen. There is no flame or embers with solar cookers,
the heat source is invisible to the naked eye if the focus is not focused
on a pot.
During the pilot project support 139 families We follow
users for almost seven months and carried out important work of raising
awareness about the risks he may be with a solar cooker. Through
this work we have obtained encouraging results, we reported only one
minor accident. A figure of 0.6%
of accidents on the project . This
result is relatively low while the women cooked almost every day with
their solar cooker.
however it was a pilot project with an almost daily user
support. Solar cooking with cookers with a very specific
focal point must be developed carefully and carried out in the framework
of projects supervised by experts and people who know the properly functioning
cookers and risks.