Sustainable Living Center Oregon
It also gives people access to safe drinking water and prevents waterborne illnesses by using solar water pasteurization.
Moderate cooking temperatures in simple solar cookers help preserve nutrients.
Those, who otherwise do not want to worry about fuels, can cook nutritious foods — such as legumes and many whole grains — that require hours of cooking with solar.
With good sunlight, solar cookers can be used to cook food or pasteurize water during emergencies.
At moderate solar cooking temperatures food doesn’t need to be stirred and won’t burn — food can simply be placed in a solar cooker and left to cook, unattended, for several hours while other activities are pursued. In the right circumstances it is possible to put a solar cooker out in the morning and return home in the late afternoon to a hot meal ready to eat.
Pots used for solar cooking are easy to clean.
The three most common types of solar cookers are heat-trap boxes, curved concentrators (parabolic) and panel cookers. Many variations on these basic types exist.
Box cookers cook at moderate to high temperatures and often accommodate multiple pots. Worldwide, they are the most widespread. There are several hundred thousand in India alone.
Curved concentrator cookers, or “parabolic,” cook fast at high temperatures, but require frequent adjustment and supervision for safe operation. Several hundred thousand exist, mainly in China. They are especially useful for large-scale institutional cooking.
Panel cookers incorporate elements of box and curved concentrator cookers. They are simple and relatively inexpensive to buy or produce.
Solar cookers are portable, allowing for solar cooking at emergency sites.
Most solar cookers work on basic principles: sunlight is converted to heat energy that is retained for cooking.
Sunlight is the “fuel.” A solar cooker needs an outdoor spot that is sunny for several hours and protected from strong wind, and where food will be safe. Solar cookers don’t work at night or on cloudy days.
Dark surfaces get very hot in sunlight, whereas light surfaces don’t. Food cooks best in dark, shallow, thin metal pots with dark, tight-fitting lids to hold in heat and moisture. Black pots absorb sun’s rays a white pot reflects sun’s rays
A transparent heat trap around the dark pot lets in sunlight, but keeps in the heat. This is a clear, heat-resistant plastic bag or large inverted glass bowl (in panel cookers) or an insulated box with a glass or plastic window (in box cookers). Curved concentrator cookers typically don’t require a heat trap.
One or more shiny surfaces reflect extra sunlight onto the pot, increasing its heat potential.
Harmful food microbes, including bacteria and viruses, are killed when heated to 150ºF. Water that has been heated for a short period of time is free from microbes including Escherichia coli, Rotaviruses, Giardia and the Hepatitis A virus. This is called pasteurization.
Food cooks at 180ºF to 195ºF, and is therefore free from disease-causing organisms when fully cooked. Simple solar cookers cook gently at temperatures just above these, so foods maintain moisture and nutrients, and rarely burn or overcook.
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