1000W Portable Lightweight Parabolic Mirror

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Last edited: 3 August 2023

Assembled Mirror using polycarbonate sheets

Disassembled mirror with other equipment

You can use branch to hold the mirror into desired position.

Assembled mirror during second test

Separate flat panels panels might be turned into parabolic shape with a cord or wire. This is main feature designer Jakub Grygier used during summer of 2022 to create portable, cheap, lightweight parabolic mirror for solar cooking which can be constructed with variety of materials.

Mirror can be constructed using polycarbonate sheets covered with reflective tape. Also simple cardboard and aluminium foil can be used. Size of the mirror might be scaled into bigger 4 square meter version.

Construction

Panel schematics

Panel assembly 1

Panel assembly 2

Panel assembly 3

It took me around 14h to assembly the cooker but I am sure less precise version can be built much much quicker. To construct the mirror you need to:

1. Cut flat panels 10cm x 100cm. If you are using cardboard instead polycarbonate sheet use tape to increase strength, durability at the edges of your panel.
2. Cover all panels with reflective material.
3. If you need some rain protection you can cover back of panels with tape.
4. Make tiny holes so panels can be connected with screws or cordage. I used an electric drill to make holes.
5. Make tiny holes on edges for the cordage which will bend panel into parabolic shape.
6. In middle of two panels make larger round hole 4cm in diameter.
7. Connect panels together with screws or cordage.
8. Use cordage to bend mirror into parabolic shape.
9. Attach mirror to stand or use cordage to attach it to branch of the tree.

Full list of elements

1. 1m x 1m polycarbonate sheet or bendable plastic or cardboard sheet. The best is a polycarbonate sheet but you can also use cardboard or pieces of cardboard which you can connect with stapler. It might be possible to build panels using aluminium cans.
2. If you are using cardboard increase strength of panels using tape. Then you can drill holes through it and cordage wont tear the endings of the panel.
3. For reflective cover use reflective tape or mylar or aluminium foil.
4. You need strong cordage. I used nylon cordage.
5. You need to connect panels together. I used M5 slotted pan screws but you can also use cordage although it might be less stable.
6. At the end of cordage use cordage stoppers. If you do not have plastic stoppers you can use small sticks to limit cordage length. You make tiny triangular cuts at the end of the panel and then you bend the panel with a cord with two sticks at the end. This way cordage must have fixed ahead length.
7. Buy PCV pipes or use a dead branch to hold your mirror. You can use cordage to regulate mirror alignment toward the Sun.
8. Use container which is black outside to boil or cook.

Usage and Portability

Panels can be transported in a backpack. If you use plastic or cardboard to construct your panels the weight should be low. To hold your mirror you can use PCV pipes or dead branch of a tree. You can also hang it on anything which does not drop large shadow onto your mirror. Then container can be attached and you can cook and boil.

During sunny, windy weather I was able to boil 1 liter of water in about 25-30 minutes. Screening the container from wind might help to boil or cook things quicker.

Scalability

It is theoretically possible to build very large portable cooker using the method presented above to make powerful but dangerous mirror. If you increase size of the panel to 10cm x 200cm you will easily be able collect around 4000 W of solar energy. iWth 39 panels 10cm x 400cm you will be able to collect and focus 16000 W of solar energy.

Using Cardboard instead Polycarbonate

Image showing that cardboard can bend into parabolic shape.

You can use cardboard instead of Polycarbonate. Durability of it will be lower but it can be done. You can tape backside of cardboard panel to increase durability. To join multiple cardboard pieces I used M6 screws but I am sure it can also be achieved with a cord. Joining multiple cardboard pieces increase stiffness. You can "regulate" stiffness of cardboard panel by using additional layers and to increase panel size.

Contact

Jakub Grygier
Wroclaw
Poland

Email: nordenworks@gmail.com