Supplies Needed to Create a Parabolic Cooker
You may choose to create a parabolic cooker. This design uses a reflective dish to concentrate and focus sunlight to a certain point where food is cooked.
Though perhaps not as efficient as a box cooker, building a parabolic design can be a fun and rewarding project.
The reflecting surface often resembles the shape of a satellite dish and can be small like the satellite receiver on your roof or may resemble the old huge satellite dish once placed in yards across the country.
Dish Shape
Anything that has the shallow curved "dish" shape can be used to create a parabolic cooker. Some do-it-yourself solar enthusiasts have used modified umbrellas as the shaped based of a home made cooker.
An old satellite dish makes a great start for a parabolic cooker. The small dish is designed to rotate and tilt which will help you aim the reflector to capture the maximum amount of UV rays from the sun.
If using a satellite dish you will need to have a sturdy base that can hold the dish without tipping over. This can be a square wooden or two or more short planks of wood fastened together.
Remove the the LNB's meant to direct the satellite signal to the dish. Remove the dish from it's mount and turn it 180 degrees and remount it.
The reason for turning the round dish upside down is to locate the mount that was used for the LNB to the top of the parabolic cooker.
Piece of Wood
This is a sturdy mount that can be modified to hold a cooking pan. A piece of wood about 1x2" will fit into that mount section.
Drilling holes every 2 inches in the wood at one end allows you to locate the rod higher or lower as you need.
Slid the wood piece into the mount and use a peg or nail in one of the holes to hold the wood in place. You could also use a metal rod or tube rather than wood.
Add a hook at one end of the wood "arm" to use in hanging a pot. Use regular white glue to adhere heavy duty aluminum foil to the inside surface of the satellite dish.
Add a little water to the glue and you'll be able to paint the glue over the entire surface. Be sure to affix the aluminum foil with the shiny side up for maximum reflection.
90 Degree Angle
Your cooker should be at a 90 degree angle to the sun. If you replace fixed mounting screws with wing nuts you can adjust the angle as needed.
Use a black cooking pot. You can use the same paint designed for use on grills or fireplaces to paint a pan you already have.
Paint both the pan exterior and the top of the lip. When solar cooking, you must have a covered pan and black works best.
Hang the pot of food from the wooden piece inserted into the dish's mount section and the pot will dangle just above the center of the cooker.
A parabolic cooker operates much like a magnifying glass does in the sun. Sunlight flowing through a magnifier can create enough heat to start a fire.
The cooker uses the dish shape to capture and concentrate the UV rays of the run much like a magnifying glass does. The result is a cooking area that works very well.
Hanging Pot
It is critical that your hanging pot be positioned so the focused reflection of the solar cooker strikes the center of the bottom of the pot.
During the day you will need to rotate your parabolic dish to keep the sun's energy focused on the bottom of the pot where the heat is needed.
The cooker requires your presence as it needs realignment every 30-45 minutes to be effective. Unlike a box solar cooker, the parabolic design needs to be refocused frequently as the sun crosses the sky.
To reach maximum efficiency in cooking you need to insulate your cooking pot in some way. This means either placing your cooking pot inside a clear glass cooking dish.
If that is not possible you can use one of the clear cooking bags available at any grocery. Simply pull the bag up around the pot and keep it loose while tying the bag closed at the top.
This creates a layer of air insulation and the sun's energy passes right through the bag and heats the food in the covered pot.
Summary
There are many plans and designs to create a parabolic cooker that can be found online. Some of the plans are expensive and require very specific supplies.
If you haven't tested other solar cooking designs it's best to find a low cost plan to create your own cooker.
You can add a more sophisticated or larger version if you decide this style of solar cooking is what you prefer. Building a solar cooker is a great way to learning more about different types of alternative energy sources.
