Solar Cooker

Solar Cooker is an eco-friendly alternative to the traditional stove or oven for cooking food. It uses sunlight instead of fuels like gas or electricity, which eventually helps maintain a healthy ecosystem and a sustainable environment. Solar cookers can be an incredible source of energy as a house appliance, this is why it is important to understand its working principle and some merits and demerits of the solar cooker. This article covers everything related to a solar cooker.

1.0Solar Cooker Definition

A solar cooker can be defined as a device which utilises solar energy or sunlight to cook food or heat fluids. It is different from the conventional sources of energy, which generally use wood, LPG, or electricity, in terms of environmental friendliness, sustainability, and cost-effectiveness. The device works on the principle of the greenhouse effect. Solar cookers effectively eliminate the use of traditional fossil fuels, which eventually reduces air pollution and cleans the environment. 

2.0Types of Solar Cookers

Solar cookers can be divided into three main types, each with distinct properties, designs, and efficiency of the device. These three types include: 

Types of Solar Cookers	Figure
Box Type Solar Cooker:  It is one of the simplest and most widely used designs of a solar cooker. The cooker is composed of an insulating box fitted with a see-through cover, usually made of plastic or glass. A dark-coloured cooking vessel is put in the box in which the transparent cover lets sunshine in. Heat is trapped by the box, and the food simmers slowly yet efficiently.
Parabolic Solar Cooker:  The parabolic solar cooker employs a parabolic reflector to concentrate solar radiation at one spot. Concentrated sunlight can create high temperatures, so the parabolic solar cooker can cook food in less time compared to the box-type cooker. Nevertheless, it needs continuous adjustment to keep the reflector perfectly aligned with the sun.
Panel Type Solar Cooker:  The reflective panel solar cooker uses reflective panels to concentrate the sun's rays on the cooking pot. It is light, mobile, and easy to operate. While it does not reach the same high temperatures as the parabolic solar cooker, it can still successfully cook food. Panel cookers are best suited for preparing small meals and are commonly employed in locations with medium sunlight exposure.

3.0Working Principle of a Solar Cooker

The working principle of a solar cooker is based on the greenhouse effect, a process in which the sunlight enters a container sealed with transparent glass and gets trapped inside, eventually increasing the container's temperature. Here is a detailed overview of how a solar cooker works: 

1. Sunlight enters: At first, sunlight enters via transparent glass or clear plastic, which gives a smooth passage to sunlight to enter the cooker. 
2. Absorption of Heat: The inside of the cooker is coloured with a dark colour that effectively absorbs the sunlight, converting it into heat energy. Dark colours are chosen as they are great absorbers of heat and light. 
3. Heat Trapping: The transparent cover helps trap the heat inside the cooker, eventually increasing the temperature within the cooker, which in turn heats the food present inside it. 
4. Insulation: Solar cookers are also equipped with insulation to avoid the loss of heat energy, which allows the food to cook at a steady rate. 

4.0Design of Solar Cooker

The design of a solar cooker generally varies depending upon the type of solar cooker; however, all these types possess some similar characteristic features in their designs, which include: 

1. Reflectors: Employed in parabolic and panel-type cookers to focus sunlight onto the cooking vessel, improving the heat generation process.
2. Cooking Pot: The pot is typically constructed from a dark, heat-absorbing material (e.g., black metal or ceramic) to maximise heat intake.
3. Transparent Cover: This is usually glass or clear plastic and is used to allow sunlight in while keeping heat within.
4. Insulation: Insulation material is used to surround the cooker to reduce heat loss and maintain the inside temperature.

See the diagram of the solar cooker given below to better understand the design of the device. 

5.0Advantages of Solar Cooker

Being a sustainable option for traditional stoves and ovens, there are many Advantages of a Solar Cooker which make it an ideal choice for cooking over other conventional methods. These include: 

• Environmentally Friendly: Solar cookers use sunlight, hence they don’t release any harmful emissions like gas, coal, or wood does. This is the reason solar cookers are considered the best source of environmentally friendly energy. 
• Cost-Effective: Although the cost of a solar cooker can be much higher, its maintenance is quite cost-effective once installed as it doesn’t need any fuel or electricity, which helps in a long-term cost-saving solution.
• Sustainable and Renewable: Sunlight is the most abundant and free source of energy on the Earth, ultimately reducing the dependence on a non-renewable source of energy that is harmful in the long term for a sustainable life. 
• Healthier Cooking: Solar cooking is the best source of energy for preserving nutrients in the food compared to conventional cooking styles due to the absence of exposure to flames or smoke, which ultimately results in healthier food. 
• Ease of Use: Once set up correctly, a solar cooker needs little to no attention, which makes it more convenient to use for people with a busy life. 

6.0Disadvantages of Solar Cooker

Despite having too many advantages, solar cookers can also possess a few disadvantages, which include:  

• The solar cooker works with the help of sunlight; hence, it depends upon good sunny weather to work properly. 
• Solar cookers are sustainable devices, however, it takes a long time to cook meals on them. 
• Solar cookers have a smaller cooking area, resulting in limited cooking capacity. 
• As mentioned earlier, the initial installation cost of a solar cooker can be very high in comparison to conventional methods.