Solar cookers are a great way to cook food using the energy of the sun. They
can be made from various materials that are available and don't require a
fuel source like other cooking devices other than sunlight. The basic
idea behind making a parabolic solar cooker involves concentrating the solar
rays to a point or region that food can be warmed at. Unlike other solar
cookers that involve trapping heat in a confined box, parabolic solar cookers
just focus the heat onto the food.
How to make a Parabolic Solar
A little intro
Here are some pictures of parabolic solar cookers that may inspire or better
explain the process.
Parabolic solar cooker
pictures This site has pictures of parabolic solar
cookers that have been used all over the world. Most of the designs
are pretty similar but some have distictly different elements that may be
more useful for different regions or building materials. The images
can be viewed larger if clicked on.
As one would suspect, parabolic solar cookers are based on a parabolic curve.
This involves relatively basic math skills for those that have finished
high school algebra. This is not always a reality in third world countries
where this is likely to be promoted so the basic design can be taught by a
volunteer or agency. This, if the level of education is high enough,
can be used as a way to teach math in schools as well. It is a direct
way to show the useful elements of math in everyday life.
Here is a good site about
cookers in India: a great introduction to the idea of solar cookersThis site is from a compilation of site that focus on India.
This site focuses on the logic of using parabolic solar cookers in
India. There is also a breakdown of the different materials and elements
important in making a cooker.
is another introduction to the different types of solar cooking This is a pdf that goes through the construction and different
types of solar cookers for developing countries.
Good site for many of the pros and cons of solar cooking This site runs through the differnt kinds of solar cookers
that can be made and a run down of what kinds are good for different situations.
i.e. how complicated the project should be. This is a good site
to look at before deciding to make one in an area that has not had them before.
Parabolic solar cookers are not going to use up precious fuel sources and
will not pollute the environment with toxic chemicals, green house gases (particularly
carbon dioxide) or obnoxious odors. Parabolic solar cookers are easy
to make and can be used to heat food or water. The time involved is
reduced because fuel does not need to be collected and a flame does not need
to be maintained.
Carbon dioxide impacts on
the environment Site covering the history of carbon
dioxide in the atosphere and the problems associated with increased carbon
rural women making parabolic solar cookers A foundation
decdicated to raising the status of women in all countries.
A short math lesson
The basic equation of a parabola is y=x^2
Remember this?!? Take your x and square it. If x is 1 then y is
1. Go over one and up one. If x is 2 then y is 4. Go over two and up
four. It is an exponential increase. This curve causes the lines
from a point source to be focused at one point. In other words, when
the sun's rays hit the sides of the cooker, the shape of the cooker causes
all of the rays to focus at one point and allow heating of whatever is there.
Manipulation of the equation can cause a change in the focal point
of the rays.
use a parabolic shape? Link from HSU showing how
the parabolic shape allows for the concentration of solar rays to cook food.
The four graph links on the right side of the page allow for the creation
of a parabola that can be printed and traced to make a cooker. TRACE A COOKER HERE
A wonderful website for determining where the focal point will be.
on making a parabolic solar cooker from the CCAT group at Humboldt State University.
This site is great for explaining how to create a solar
Constructing your cooker
Things to remember when collecting materials:
1) the inside will need to be shiny to reflect solar rays
2) the dish will need to be on some sort of platform to angle it in the direction
of the sun
3) think about where it will be used and for what (size) and how much it will
be moved around (weight)
4) optional: an arm or bar to hold the food or pot
A previous example of making a parabolic cooker.
Some more basics
about parabolic cookers This is another good site
for tracing a parabola. This site explains how the curvature of the
parabola reflects all the sunlight to the same source. TRACE A COOKER HERE
Thinking about (1)
Anything shiny to line the sides of the cooker will work.
Most often metal is used but when working in a situation with few resources,
it is time to get creative. Snow is quite reflective and the solar
rays will be focused not on the snow but above it so a makeshift snow solar
cooker is a possibility. Foil pieced together will work such as gum
wrappers or packagings of candy.
Thinking about (2)
As most of us have notice, the sun moves across the sky,
it doesn't stay in one place. Therefore, the cooker should be moveable
to focus it in the direction of the sun.
A site that describes
a way in which to reduce movement during cooking This site shows how a cooker can be left for long
periods of time without the need to continuously move it to face the sun.
Thinking about (3)
Start small unless you know what you are doing. When
adding materials together the cooker can become heavy. Once you know
your materials better and the stability of the design you use you can determine
how large you want to make your cooker. Roasting marshmellows and cooking
a chicken will involve different amounts of light and therefore different
sizes of cookers.
Simple construction techniques
Great site for cheap ways to make a cooker. This
site has a design for using a winebox which is one of the simplest and cheapest
ways to create a solar cooker.
Thinking about (4)
One option is to hold the food using a stick but this may
get tiring. Having an arm that extends over the focal point that is
moveable to allow for different sized items is a good possibility. Another
is to have a bar that is attached at both ends. This may be more feasible.
Great site involving the different
materials involved This site goes through set by
step how to make a parabolic solar cooker including the materials and how
to put the layers of the parabola together.
Thinking about (5)
The cost of making a solar cooker can vary greatly. The
cheapest way is to make it out of basic materials such as a wine box (also linked
under thinking about (3)). This would require a wine box, some scissors
or exacto knife, some paper to give the ridges a little more stability, and
a reflective surface (foil). The box can be picked up free at a grocery
store or liquor store and the other materials shouldn't cost more than a
few dollars. More costly cookers can be made or even bought (see the
last section). Of course, the better a cooker is made the better it
will work but it is likely to be more expensive to make or the materials
will be harder to get ahold of.
Depending on how you want to cook your food, a perfect focal point may not
be what you want (YEAH! you don't have to be perfect with your construction).
If the focal point is more diffuse then you can cook over a larger area.
If your focal point is very accurate then that one point will get very
hot. So, toss some food on a stick or grab a pan (the darker the better)
and start cooking.
An international organization that has a strong focus
on the use of solar energy.
A great source of information Runs through some of the costs associated and different
ways to tweek a parabolic solar cooker into more uses.
Another site for solar cooking created by another Peace Corps volunteer
This site runs through the main points of solar cooking
with a focus on
Solar cooking in Nepal
This site includes a manuel on making solar cookers
and suggested local materials in Nepal.
solar cooking in Ethiopia Site runs through making
cookers in Ethiopa including specific projects.
Energy saving in
Hawaii This site discusses the future of energy
in Hawaii and the pros and cons of solar energy in Hawaiian homes.
a site that looks at the many
aspects of solar use This site is a do-it-yourself
site for creating a solar home
Not feeling the urge to make one? then buy one
Here are some sites for buying solar cookers. They may inspire a design
for your own.
SolarReflex Parabolic Cookers
This site sells solar cookers of all shapes
and sizes for different uses. Prices range from $10 to $160.
the more high tech cooker This is a website for
alternative energy hobbies. It contains materials for making parabolic
solar cookers that can be used for more high tech cookers.