Introduction. The insight for this project came from two community members: Mintyhippo and pepi. Special thanks to them. I became interested in solar cooking a few months ago. Having surfed several solar cooking sites, I decided to make a solar cooker. This one turned out to be rather efficient. It won’t take you long to build it. You may use materials scattered around the household. The cooker can be easily built by a junior school student (with exception of metal work, it should be done by an adult). So you are welcome to give it a try.
Step 1: Motivation
Motivation. I spent a couple of weeks in the countryside in summer. So I needed a portable and cheap solar cooker. This cooker met all my requirements. Being in the countryside, we (my wife and I) left it in the sun and went to the woods to pick up berries. When we were back (in 3 or 4 hours) we could enjoy delicious fruit dessert. We also were able to cook rice, boil eggs and brew tea and coffee.
Materials and Tools. 1 sheet of drawing paper (size A0), a window shade (as reflective material), 1 glass jar with a metallic screw-on lid (0,5L), 1 aluminum beer can (0,33L), 1 water dispenser bottle(5L) cap, 2 lengths of ribbon, adhesive tape, black paint (preferably flat)
You need few tools: a scissors, a cutter (for metal work), a paint brush (if you don’t use a spray).
Step 3: Make a Bag
Make a Bag. Go to How To Make An Origami Cup posted by Mintyhippo. Using a sheet of drawing paper, make a BIG cup. Attach lengths of ribbon on its sides with adhesive tape and you have a bag. Place the bag on a folded (2 layers) window shade and cut out the lining. Insert the lining into the bag and fix it with adhesive tape.
Some metal work to do. Take a beer can and cut out the upper lid with a cutter. You have a food container now. Take a glass jar lid and cut out a hole in the center. The diameter should be the same like the diameter of the top of the beer can. It should go through the hole with friction. Now press the beer can against the hole and the top of the can goes through it. It’s time to paint the can in black.
Prepare a glass jar. Remove a label from the jar and wash it clean. Insert the beer can into the jar and screw on the lid. Your solar cooker is ready.
Step 6: Time to Test
Time to test. On a sunny day pour 200 mL of water into the beer can and plug it with a water bottle cap. Place the bag on the ground and point it to the sun. Place the jar inside the bag. Tilt the apparatus a bit to get more solar energy. On a hot sunny day temperature change exceeds 30C in an hour. You may pull a woolen sock (preferably black) on the top of the jar to retain heat.