Solar Cooker

A solar cooker is a device that cooks food by employing the energy generated by the Sun, i.e. solar radiation. Cooking vegetables, meat, and rice on stoves and ovens is common. We can prepare the same meal with a solar cooker, except using gas or electricity, we may use a naturally available resource: sunlight. It is based on the conversion of light energy into heat energy. In this post, we’ll look at how a solar cooker works, its operating principle, construction, and the benefits and drawbacks of employing one.

Solar cooker

A solar cooker is a device that uses the energy of direct sunlight to cook food. It commonly uses reflecting panels to focus the light on a dark-colored pot inside an insulated box.

The electromagnetic radiation generated by shifting electric and magnetic fields is referred to as sunlight. Whenever photons from light waves collide with molecules in a substance, heat is produced. The electromagnetic radiation emitted by the Sun contains energy. The energy causes the matter molecules to vibrate as they collide. The molecules gain energy and soar to new heights. As a consequence, heat is created.

We use the energy provided by the Sun to cook our food in a solar cooker with a concave mirror in this way. Concave mirrors are employed because they reflect the sun’s light to a single point called the focus. The solar cooker works on the principle that the sun warms the pot where the food is prepared. By converting light energy into heat energy, the pot is warmed. The sun’s rays are focused onto a receiver, in this example a cooking pan, by the concave mirror. UV rays enter a solar cooker, where they are converted to longer infrared light rays which cannot escape.

Solar cooker Working Principle

Sunlight Concentration:

A mirror surface with a high specular reflection is used to concentrate and channel light from the sun into a small cooking space. The sun’s power can even melt salt and metal, although these extreme temperatures aren’t needed for solar cooking at home. As a result, solar cookers on the market are built to reach temperatures of 650 to 4000 ℃.

Converting Light Energy into Heat Energy:

A receiver, including a cooking pan, receives the concentrated sunlight. Solar cooker pots and pans must be matte black to enhance absorption. Conduction changes light energy into heat when it interacts with the receiver.

Trapping Heat Energy:

The use of a glass lid on the pot enhances light absorption from the top of the pan, lowers convective energy loss, and improves the heat holding ability of the cooker. Infrared thermal rays can travel via the glass, but it is opaque to incoming sunlight.

Types of Solar cooker

Solar cookers are primarily separated into two types:

Box Type

In this form of cooker, heat is reflected by a reflector into a box, then trapped by the top glass, generating a greenhouse effect which heats the cooking utensils. 

The most prevalent type of solar cooker is the box-type solar cooker. A box-type solar cooker has the following parts:

• The black box is an insulated metal or wooden box which is painted black on the inside to absorb heat.
• A cover made of two sheets of toughened glass linked together in an aluminium frame is used to cover box B.
• Box B has a cotter pin plane mirror reflector. The mirror reflector can be pointed in any direction towards the box. The mirror is positioned so that the reflected sunlight falls on the glass lid of the box.
• A set of blackened aluminium canisters can be found in box B.
• A plane mirror reflector is used to position the solar cooker in the sun, allowing a strong beam of sunlight to enter the box through the glass sheet. The heat generated by infrared radiation absorbed by the blackened metal surfaces in the wooden box increases the temperature of a blackened metal surface to nearly 100℃.

Parabolic Type

The heat converges in a place where the cooking equipment is housed, heating and cooking the meal.

There are also subcategories such as:

Cookers in boxes (often called box ovens)

Cookers with a parabola

Cookers in tubes

Solar Cooker Pros and cons

Pros

Solar cookers don’t use fuel, permitting us to save money while also helping to protect the environment by reducing pollution.

Cooking with non-carbon-based fuels decreases carbon emissions.

Cons

Solar cookers are less effective when it is cloudy.

Some solar cookers take longer to cook food than a conventional stove or oven.

It may be difficult to prepare some thick dishes, including large roasts and loaves of bread.

Some solar cookers may be influenced by strong winds, slowing down the cooking process.

Conclusion

A solar cooker is an appliance that cooks food using the energy of direct sunshine. Reflective panels are typically used to focus light on a dark- colored pot inside an insulated box. Cooking with solar energy is a fuel-saving approach that can be extremely beneficial in times of fuel constraint. Solar cookers, particularly cooking boxes, can be effectively built locally.