Explain the construction and working of solar light, solar water heating system and solar cooker with the help of neat and labeled diagrams
Answers
THE CONSTRUCTION OF SOLAR STREET LIGHT. Solar lighting system is the use of natural light to provide illumination. Solar lighting system is the technology of obtaining usable energy from the light of the sun using semiconductor materials and this is energy efficient lighting technology.
Solar water heater uses radiation from the sun to heat up water. Solar water heater does not consume any fuel, so it is used in developing countries like in Africa where fuel is relatively expensive but sunlight is abundant. ... A simple solar water heater can be constructed using everyday materials.
Construction of a box-type solar cooker: A box-type solar cooker consists of the following components:
Box (B): This is an insulated metal or a wooden box. It is painted black from inside because black surface absorbs more heat. The box may be provided with four roll-wheels.
Glass cover (G): A cover made of two sheets of toughened glass held together in an aluminium frame is used as a cover of the box B.
Plane mirror reflector ®: A plane mirror reflector fixed in a frame is fixed to the box B with the help of hinges. The mirror reflector can be positioned at any desired angle to the box. The mirror is positioned so as to allow the reflected sunlight fall on the glass cover of the box.
Cooking containers ©: A set of containers made of aluminium and blackened from outside are kept in the box B. These containers are also painted black because black surface absorbs more heat.
Working: The food is cooked in a shallow vessel of the container. The box has a transparent covering of glass sheet over it. The solar cooker is placed in sunlight and reflector (plane mirror) is adjusted in such a way that a strong beam of sunlight enters the box through the glass sheet. The blackened metal surfaces in the wooden box absorb infra-red radiations from the beam of sunlight and heat produced raises the temperature of blackened metal surface to about 100°C.
The food absorbs heat from the black surface and gets cooked. The thick glass sheet does not allow the heat produced to escape and thus, helps in raising the temperature in the box to a sufficiently high degree to cook the food.
