|
Solar Cooking
Overview
Types of Solar Cookers
Global Highlights
What’s Happening in B.C.
Environmental and Social Matters
Benefits
Can I Use it at home?
What Does it Cost?
Links
Footnotes
Overview
The Essenes, many years ago, heated wafers of grain placed
on rocks in the desert sun. Much later in 1767, Swiss naturalist,
Horace de Saussure, successfully cooked fruit in a solar
box reaching temperatures of 189.5 F. The Rig-Veda says” food
cooked by Sun rays is lovely in appearance, aroma, flavour
and taste. It is the ultimate medicine…” Ancient
wisdom on solar cooking.
Many designs of solar cookers are now available - from simple
home-built box ovens of wood and glass (even woven straw
or cardboard), to factory manufactured thermo-plastic solar
electric hybrid ovens and aluminum formed parabolic solar
barbecues.
Types of Solar Cookers
Hybrid Solar Cooker |
All solar cookers use direct or reflected sunlight to either
focus or capture heat to cook food in dark coloured pots.
A few models are designed to operate at high efficiencies
during periods of cloud or darkness using supplementary power
of electricity or natural gas. The efficiency and cooking
temperature of different cookers varies in relation to their
size, materials and methods of construction, quantities of
food cooked, and the intensity of available sunlight.
Box Cooker
- An insulated box covered with a flat or slanted piece of glass .5mx.5m
( 20”x20”) min
- One or more reflective panels are usually attached
to reflect additional sunlight into the box and heat
is captured via the greenhouse effect.
- Slow, even cooking with minimum attention - food
cannot be burned.
- Built of a variety of materials and is relatively
portable
- Can be permanently built into a kitchen wall that
has good solar exposure. (footnote 3)
Parabolic and Concave Cookers
- A reflector about 1.5m (60”) diameter
focuses sunlight on to a cooking pot.
- Achieves very hot temperatures and quickly cooks, sautés,
or barbecues.
- Made of aluminum or stainless steel.
- Less portable and usually must be secured or permanently
mounted.
- Available in various sizes and configurations
Panel Cookers
- Numerous flat reflective panels surround
and concentrate sunlight to a dark pot that is covered
by a second clear pot or clear heat resistant bag.
- Portable and inexpensive.
- Appropriate for hikers, refugees, or the homeless.
Community Scale Cookers
- Sophisticated trackers and parabolic reflectors of
a fixed cooker that feeds 100’s of people.
- The simple “Villager Sun Oven” is a large
box oven that mounts on a trailer.
Global highlights
China and India each has 25 to 30 years experience in solar
cooking technology and are global leaders. Solar cookers are
well subsidized, with China having manufactured an estimated
560,000 solar cookers (footnote #1), while India has an estimated
400,000 solar cookers (footnote #2). Solar cooking technology
has been introduced to most developing countries, although
programs have been slow to develop due to lack of funding
combined with social and political factors. Many NGO’s,
scientists and other experts are assisting in research and
development.
What’s happening in B.C.?
Currently in B.C., most solar cookers are located in remote
locations without access to the grid, where cottages and
homes rely on renewable energy or propane for cooking.
Some people in B.C. have helped develop solar cooking in
India, Nepal, and Mexico; an example is Powell River’s Community
in Partnership that has contributed in the promotion and
construction of 500 to 1000 solar ovens in Haiti. Some urban
British Columbians use solar cooking and some students in
B.C. have constructed “pizza-box solar cookers” as
science projects.
Environmental and Social Matters
Sun Oven |
Cooking has a significant global impact. ½ of
humanity (about 3.25 billion people) rely on burning wood
or dung to cook their food. 18 African countries rely on
fuel wood for at least 73% and up to 97% of their total
energy consumption. For example, fuel wood as percentage
of energy consumption in a developing country equals 97%
in Nepal, 63% in Thailand and Sri Lanka, and about 35%
in the nations of Pakistan, India, Brazil and El Salvador
(footnote #3). The resulting de-forestation create a plethora
of socio-environmental problems. These include global warming,
landslides, desertification, massive displacement of people,
health problems including burns and respiratory illness,
and increasing assault and abduction of women and children
who forage daily for firewood. 2 billion people live near
or in tropical latitudes where daily bright sunshine is
common year-round (footnote #4). In these regions, solar
cooking could provide much of the cooking required. Every
where on the globe solar cooking requires lifestyle adjustments,
especially for women. These include changes in timing and
routines for the preparation of meals, and flexibility
and skill in terms of the weather and sunlight.
Solar Cooking Benefits
- Slow cooking temperatures can enhance flavours
and preserve nutrients
- Saves time and dinner is ready when you come
home.
- Solar cooking keeps the kitchen cool and comfortable.
- Solar cooking in summer decreases the need for
home air-conditioning..
- Electrical consumption is reduced at dinnertime
during peak demands, helping create a more secure electrical
grid.
- Great for camping or during an emergency.
- Illuminates solar power in practical terms.
Can I use it at home?
Yes, it is possible. In most of B.C. solar cooking can be
utilized commonly for 6 to 8 months of the year (March/April
to September/October), and almost daily during the summer
months. Two requirements are essential:
- A sunny location in your yard or balcony
- Properly orient the solar cooker towards the
sun.
In southern B.C. it is possible (with luck!) to solar
cook during any month of the year. During fall and winter
months increased cloudiness compounded with shorter daylight
hours and the sun being low in the sky, result in less
solar energy available. During these months, it is not
recommended to leave solar cookers unattended because frequent
solar adjustments are required to ensure adequate cooking
temperatures. For food safety, an oven thermometer must
always be used when solar cooking.
What does it cost?
Manufactured solar box cookers are available in B.C. by
importing them from the U.S.A. or India. Prices range from
$150.00 U.S. to about $300.00 U.S. Parabolic solar cookers
are also available from Germany or the U.S.A., at slightly
higher prices. Using woodworking or metalworking skills,
solar cookers can also be home-built.
Links
Sun Oven
International
Solar
Oven Society – SOS Sunstove®
Sun BD
Corporation
Solar Household
Energy (SHE)
The
Solar Cooking Archive
Footnotes
- Solar Cookers International – July 2003 Solar
Cooker Review
Development and application of Solar Cookers in China
- Solar Cooking Technology– How
Far are Technology Promoters and Users From Each Other? http://solarcooking.org/gujarat.htm
- Solar Cooking Archive http://solarcooking.org/fuelwood.htm
- Map of The Reach of Solar Cooking – A Technology
Whose Time Has Come http://www.she-inc.org/map.htm
- Solar Wall Oven at http://solarcooking.org/bkerr/swo.htm
Credits
Written by Bruce Witzel for the BCSEA
Text updated May 1st, 2006
Links updated September 7, 2007
|
