Question

Draw a well-labeled diagram of a solar cooker and write its functions.

Answer 1

Solar cooker

A solar cooker is a form of a solar thermal collector. The box-type solar cooker is the most common type of solar cooker.

The solar cooker consists of the following components:

1. Reflector - These are the plane mirrors used to reflect sunlight to the inner metal box.
2. Glass Sheet cover - It is a thick glass lid that is used as the cover on the inner metal box. It receives the light from reflectors and lets rays pass through it.
3. Inner Metal Box - It is the main container of the solar cooker, made up of metal to absorb more and more heat.
4. Thermocol - It is the outer covering of the inner metal box. It is used for preventing heat to escape from the inner metal box.

Working principle of a solar cooker

Concentrating Sunlight:

1. To concentrate and channel light from the sun into a tiny cooking space, a mirror surface with high specular reflection is employed.
2. The sunlight can be concentrated by multiple orders of magnitude, resulting in magnitudes that can melt salt and metal.

Converting Light Energy to Heat Energy:

1. A receiver, such as a cooking pan, receives the concentrated sunlight.
2. The interaction of light energy with the receiver material aids in the conversion of light to heat through a process known as conduction.
3. The conversion rate is increased by using heat-conducting and heat-retaining materials.

Trapping Heat Energy:

1. By isolating the air inside the cooker from the air outside, convection is much less likely to occur.
2. Using a glass lid on the pot increases light absorption from the top of the pan, reduces convective energy loss, and improves the cooker's heat holding ability.
3. The glazing allows infrared thermal rays to pass through but is opaque to incoming sunlight.

Uses of a solar cooker

1. A solar cooker is a device that heats, cooks, or pasteurizes beverages and other foods using the energy of direct sunshine.
2. A solar cooker is used for water distillation.
3. It is used for roasting coffee and peanuts for commercial purposes.
4. It is used for grain sterilization.
5. It is also used for melting wax.