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INTRODUCTION
The concept of solar cooking began over 220 years ago and was used
by the French Foreign Legion starting in the 1870's. All solar cookers work on
the principle of concentrating the direct solar rays to raise food or water to
cooking temperatures. Cooking temperatures begin at about 150 degrees F.
although temperatures of 250 to 400 degrees F. are preferred.
Open reflector type solar cookers focus the sun's rays on open cooking
pots or pans. Solar ovens trap the sun's heat inside insulated boxes with transparent lids. Most solar
ovens are variations of the bread box type developed by two Arizona women, Barbara Kerr and Sherry
Cole.
These simple box cookers created in the 1970's are now being used world
wide to overcome food shortages in developing countries. In places like Eastern
Africa native women travel 20 to 30 miles to gather a two day supply of cooking
fuel. In other parts of the world increasingly high rates of malnutrition are caused
by a lack of fuel. Basic grain foods cannot be cooked without cooking fuel and
water infected with chronic bacteria must be heated before drinking. Continued gathering of wood
cooking fuel by chopping down trees has resulted in eroded hill sides with loss of precious topsoil thus
reducing their ability to grow food.
In America we concern ourselves with such things as
operating costs, air pollution, acid rain and the green house
effect. Let's say it takes one hour to cook a pot of beans on an
electric stove using one kilowatt. The coal fired power plant
that supplied the electricity consumed one pound of coal and
released 17.5 cubic feet or two pounds of CO2. The power plant also consumed 0.7 gallons of ground
water and released traces of SO2 as acid.
Suppose you are cooking outside. Five pounds of steaks on a grill will use a ten pound bag of
charcoal and five ounces of lighter fluid. This fire will produce approximately 160 cubic feet or fifteen
pounds of CO2 and untold air pollution. Wood fires are even worse.
Cooking in the home averages over 100 hours a year consuming approximately 1,175 kilowatt
hours. At a cost of $0.10 a kilowatt hour this amounts to $117 a year. During the summer cooking adds
$50 to the air conditioning bill bringing the total to $167 a year. In Arizona, solar cooking can replace
70% of the cost of cooking. This will save 1,675 pounds of coal and 3,000 pounds of CO2 generation
from coal fired electric utilities.
Clearly solar cooking has come of age.