About 150 million tons of firewood are burnt yearly for cooking in the rural
areas of India by the poor sections of society (Garg 1978). The ovens and chulas
(fireplaces) used are quite crude and inefficient. Due to scarcity of firewood,
the rural population is switching to kerosene as the domestic cooking fuel. This
tendency needs to be curbed to conserve foreign exchange reserves, which is why
solar cookers or ovens are being developed in this country.
India is a pioneer in the development of solar-cookers. The first cooker was
produced in India in 1950 and became commercially available in the 1960s but it
did not become popular at that time due to the cheap availability of cooking
fuels. However, demand is being felt now. The cookers are becoming popular in
Gujarat and Maharashtra states. Two models of solar cookers have been developed.
The conical shaped sun-basket, made from fibre glass-reinforced plastic (FRP),
serves as solar cooker and baking oven by concentrating the sun's rays at a
point where a temperature of 110° C can be achieved within a period of 5 to 10
minutes on clear sunny days. The initial cost of this basket is about Rs 600.
The reflector needs to be rotated to track the sun.
The hot box type solar oven works as an air-tight box with double glass
covers, in which one or more cooking containers can be placed. It requires more
time than the sun basket to cook food but it is able to maintain the temperature
for a longer duration, making it useful during intermittent sunshine. The
initial cost of this oven is about Rs 500. The major problems being experienced
in the adoption of these cooking devices are:
- It is difficult to produce a solar cooker at competitive prices for
indoor kitchen use. No housewife prefers to cook in the sun.
- About 70
per cent of the rural population cook their meals in the early morning before
going to work and in the night after returning home. which is not possible by
the use of solar cookers. It will be necessary, therefore, either to change
cooking habits or to provide low-cost heat storage.
- Solar cookers and
ovens require more time to cook meals than do conventional methods, and
sometimes it becomes difficult to cook even at noon when radiation is very low.
This variation is not acceptable to most families.