Solar Cooker

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What is a Solar Cooker?

We use a solar cooker for cooking the food by using the energy radiated by the Sun.

Solar cooker works on the principle that sunlight warms the pot, which is used for cooking the food.

Now, this warming of the pot occurs by converting light energy to heat energy.

Concave mirrors are used in these types of cookers because these mirrors reflect sunlight into a single focal point.

Here, the mirror focuses sun rays onto a receiver such as a cooking pan.

A solar cooker lets the UV light rays in and then transforms them into longer infrared light rays that cannot escape.

Infrared radiations have the energy to make the water, fat, and protein molecules in food vibrate energetically and heat up.

The process by which the interaction between the light energy and the receiver material turns light to heat is called conduction.

We can maximize this transformation by using materials that can conduct and retain the heat. 

Types of Solar Cooker

There are two types of solar cookers, that is:

  1. Type 1 - Box Type - Heat Up

In this type of cooker, heat gets reflected by a reflector into a box, and then the heat gets trapped by the top glass like a greenhouse effect and heats the cooking utensils.

  1. Parabolic Type - Converge Heat to a Single Point

In this type, the heat converges to a  point where the cooking utensils are kept; it gets heated up and cooks the food.

Other categories are:

  1. Box cookers (often called box ovens)

  2. Parabolic cookers

  3. Tube cookers

Box Type Solar Cooker

The main components of box-type solar cookers are:

  1. An insulating metal box painted black from the inside,

  2. A glass sheet, and 

  3. A reflector such as a plane mirror.

Let’s understand the working of the box-type cooker:

The box is covered by a transparent glass sheet which allows the infrared rays coming from the sun to enter in the box. 

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The metallic box is painted from inside and acts as a black body as we know that the black body absorbs the lights of all wavelengths.

Similarly, this box absorbs these infrared rays and heats up.    

We also know that the black body in heating up radiates all the lights of varying wavelengths absorbed by it. This box also starts emitting the infrared rays absorbed by it. 

However, the glass sheet surrounding the box doesn’t allow the heat to go out. 

In this way, a glass sheet enables the cooker to entrap heat inside the box.

Making of Solar Cooker

       Let us make a box-type solar cooker for household use.

Materials Required:

  1. A wooden box having a thermocol lining inside,

  2. Aluminum sheet,

  3. Black paint,

  4. Mirror,

  5. Glass sheet,

  6. Hinges,

  7. Wooden lid for the box, and 

  8. Containers to cook food

Construction: 

 Step 1: Take a wooden box and make a box out of the aluminum sheet.

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 Step 2:  Paint the inner side of the aluminum box with black paint.

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Step 3: Place this box inside the wooden box

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Step 4: Now, fix the mirror to the lid, and with the help of the hinges, fix the lid to the wooden box.

Step 5: Now, cover the box with a glass sheet.

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Step 6: Now, to cook the food, paint the containers in which we wish to cook, and paint these utensils with black color from outside.

Step 7: Place these containers filled with food items inside the box.           

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Result:

The glass sheet helps in entrapping the heat inside the box and the mirror converges the light onto the box, heats it and the solar cooker is ready to cook the food.

Advantages and Disadvantages of Solar Cooker

Advantages:

  1. Pollution-free.

  2. They don’t use fuel.

  3. Solar energy is freely available.

  4. Very low management cost.

Disadvantages:

  1. We can use solar energy at a certain time during the day.

  2. We cannot use it at night, during the rainy season, or during foggy winters.

  3. It is time-consuming as compared to the normal cookers.

Solar Pressure Cooker

Let us make a parabolic solar cooker to understand how solar pressure works.

Materials Required:

  1. Take a parabolic dish from the old TataSky receiver.

  2. Solar reflective film and cut it into small pieces of equal sizes.

Construction:

  1. Now, clean the surface of this dish rec.

  2. Paste the reflective films on the entire surface of the receiver as you can see below:

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  1. Make sure no bubbles are trapped inside the films.

  2. Now, connect the reflector on the stand.

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  1. Fix a holder in the front of this surface, and place the cooker on this holder.

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This is how we can cook the food in the pressure cooking using the parabolic solar cooker.

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Result: Parabolic solar cookers converge sunlight to a single point. 

When this point is focused on the bottom of a pressure cooker, it can heat it quickly to very high temperatures.

FAQ (Frequently Asked Questions)

Q1: Which Type of Mirror- Concave, Convex or Plane would be the Best for Use in a Solar Cooker, and Why?

Ans: The perfect mirror is the concave mirror because it is the converging mirror. When light strikes on the mirror, all the UV rays coming from the Sun get concentrated to a single focal point on the cooker, therefore, making the cooker heat up and helping in cooking the food.

Q2: Is Solar Cooking Healthy?

Ans: Yes.

Cooking the food in a solar cooker is healthy. The food doesn’t lose its essential vitamins and other nutrients.

Furthermore, the food prepared is free of mutagens and carcinogens produced in traditional high-heat methods. 

Q3: How could Solar Cooking Help Prevent illness?

Ans: The solar cooker works as a supernatural weapon to combat environmental issues like air pollution.

It doesn’t leave residues like ash and acts as a source to substitute traditional cooking methods, which impact the environment.

Q4: What are the Advantages of Parabolic Cookers?

Ans: The advantages of  parabolic solar cookers are:

  1. They are environment-friendly.

  2. They direct light to a smaller area to generate high temperatures in the order of 350 °C (662 °F), allowing the food to be fried.