Build Your Own Sun Cooker with Basic Supplies

Building a homemade Sun Cooker is easier than you think.

What you need:

1. An old tyre.

2. a glass square (or plexiglass) big enough to cover it.

3. a black pot.

4. silver foil (aluminum foil).

5. newspaper.

6. tape.

7. cardboard.

8. something to weigh the glass down (eg. bricks or plastic bottles filled with water).

9. and some sun!

Step 1

Place the cardboard on the ground, making sure that it is flat. This acts as extra insulation for the oven.

Step 2:

Put the tyre onto the cardboard. Check that there are no gaps between them. The tyre absorbs heat from the sun.

Step 3:

Add newspaper all around the inside and the base of the tyre. The newspaper traps air and adds more insulation.

Step 4:

Put a base of silver foil inside the tyre to reflect the heat.

Step 5:

Add a long length of silver foil all around the sides and inside of the tyre. This acts as your main solar reflector (like a mirror).

Step 6:

Try to make sure that there are no gaps. Then tape the ends together.

Step 7:

Tape the edges of the square of glass to avoid accidents. A circular piece of glass will be even safer.

Step 8:

Place a black pot into the middle of the tyre; using a black lid is even better. Try a stew without much water content at first.

Step 9:

Put the glass on top of the tyre, ensuring there are no gaps. Add some weights to avoid heat leaking out of the oven.

Step 10:

Make sure that your oven is in full sun with no shadows. Leave it for about 3-5 hours, depending on the strength of the sun and what you are cooking.

Step 11:

Check your food to see if it is cooked. Try not to let too much heat escape – be careful, it may be very hot. Then taste it!

How it works:

Solar radiation enters through the glass and the UV light is trapped inside the oven. Light reflects off the silver foil and warms the heat-absorbing black pot. Heat is kept in the oven by the newspaper and cardboard insulation. The black tyre absorbs the heat and heats up the whole cooker. Additionally it adds extra insulation to the whole device.

Under strong sunlight the temperatures inside the tyre rises up to 100ºC within 2-3 hours. Individuals who have tested this device have been able to boil water in two hours. On a cloudy day the temperature rise is less and one may have to leave the pot in the sun for longer.