Solar Cooker - Advantages and Disadvantages

Advantages and Disadvantages

Solar cookers use no fuel, which means that their users do not need to fetch or pay for firewood, gas, electricity, or other fuels. Therefore, over time a solar cooker can pay for itself in reduced fuel costs. Since it reduces firewood use, the solar cooker reduces deforestation and habitat loss. Since there are about 2 billion people who are still cooking on open fires, widespread use of solar cookers could have large economic and environmental benefits.

Solar box cookers attain temperatures of up to about 165 deg. C (325 deg. F), so they can be used to sterilize water or prepare most foods that can be made in a conventional oven or stove, from baked bread to steamed vegetables to roasted meat. When solar ovens are placed outside, they do not contribute unwanted heat inside houses.

Solar cookers do not produce any smoke as a product of combustion. The indoor concentration of health-damaging pollutants from a typical wood-fired cooking stove creates carbon monoxide and other noxious fumes at anywhere between seven and 500 times over the allowable limits. Fire-based cooking also produces ashes and soot, which make the home dirtier. However, any type of cooking, including solar cooking, can evaporate grease, oil, etc., from the food into the air.

Unlike cooking over an open fire, children cannot be burned by touching many types of solar cookers, which are made from cardboard or plastic and do not get hot. Unlike all fuel-based cooking arrangements, these solar cookers are not fire hazards. However, solar cookers that concentrate sunlight, e.g. with paraboloidal reflectors, do produce high temperatures which could cause injury or fire.

Solar cookers are less usable in cloudy weather and near the poles (where the sun is low in the sky or below the horizon), so a fuel-based backup heat source is still required in these conditions. Also, solar cooking provides hot food during or shortly after the hottest part of the day, rather than the evening when most people like to eat. The "integrated solar cooking" concept accepts these limitations, and includes a fuel-efficient stove and an insulated heat storage container to provide a complete solution.

It has been recognized that solar cookers are limited to cooking on clear days. Moreover, most people want to eat hot food late in the day, when the sun is low or has already set. For these reasons, solar cooking advocates are recognizing the need for combining three devices for a total cooking solution: a) some type of solar cooker; b) a fuel-efficient cookstove; c) an insulated storage container such as a basket filled with straw to store heated food. Hot food will continue to cook for hours if it is stored in a well-insulated container. With this three-part solution, fuel use is minimized while still providing hot meals reliably. This concept is referred to as "integrated solar cooking" or the "integrated cooking method".

Many solar cookers take longer time to cook food than a fuel-based oven. Using these solar cookers therefore requires that food preparation be started several hours before the meal. However, it requires less hands-on time cooking, so this is often considered a reasonable trade-off.

Cooks may need to learn special cooking techniques to fry common foods, such as fried eggs or flatbreads like chapatis and tortillas. It may not be possible to safely or completely cook some thick foods, such as large roasts, loaves of bread, or pots of soup, particularly in small panel cookers; the cook may need to divide these into smaller portions before cooking.

Some solar cooker designs are affected by strong winds, which can slow the cooking process, cool the food, and disturb the reflector. In these cases it is necessary to anchor the reflector with string and weights.