Solar funnel cookers are the least expensive and easiest solar cooker to construct. Solar funnel cookers are portable, making them ideal for campers, including RV owners and backpackers. Even kids can help with the construction of solar funnel cookers. It is the ideal do-it-yourself solar project, melding both cost-efficiency and environmentally friendly energy use.
The first step in constructing a solar funnel cooker is to cut a half circle along the bottom of the cardboard sheet. This circle should have a radius that is equal to half the diameter of the container used for cooking. If a standard mason jar is used, the half circle’s radius would be approximately five inches.
The half circle that was cut into the bottom of the cardboard sheet will be used to make the funnel. Slowly bend the two sides of the cardboard together around the half circle. A funnel shape should form. Allow the cardboard to crease as this will give guidelines for the funnel once the aluminum foil is attached.
Next, lay the cardboard sheet back down onto the floor or work surface. Using the spray adhesive or white glue (mixed with equal parts water), adhere the aluminum foil to what will be the inside of the funnel. Be sure the foil is shiny side up and no bubbles or breaks occur.
Once the aluminum foil has adhered to the cardboard, bring the funnel together again. Use the metal brads to attach the two sides together. Space the brads evenly down the edge where the two sides meet and lock into place. Glue a section of aluminum foil over the brads on the back of the cooker, shiny side down, to ensure heat retention. The funnel of the cooker is now assembled.
Spray with black paint a square of wood approximately two inches wide by four inches long and two inches deep. Place this block in the bottom of an oven bag. Set the Mason jar (with the food or water contents inside) on top of the wood, inside the bag. Blow air into the bag to inflate it. Tie the bag off at the top. This creates a greenhouse effect inside the bag.
Lastly, place the bag inside the funnel of the solar cooker. Be sure the apparatus is facing the sun. The solar funnel cooker can be placed in a cardboard box or a hole dug into the ground for stability.
Solar cooked foods will not burn, as the heat is slow and moderate. The best cooking times are when the sun is highest in the sky and the cooker is left in direct light. Cooking times for items vary and some will require water to be added.
Most vegetables can be cooked in an hour and a half, as will roast nuts. Neither of those items require water to be added. For grains, use a mix of two parts water for every one part grain; this should be ready to serve within two hours. Meats, chicken and fish vary on cooking times due to their size and density. Generally, fish takes one to one and a half hours, while chicken and meat will cook between one and a half and three hours.
The solar funnel cooker is cost and eco-friendly. It requires very little effort to construct and is portable. There are a variety of uses for the solar funnel cooker, from cooking foods to pasteurizing water. Solar power can be harnessed in many ways, but perhaps the simplest is through solar cooking. Solar cookers make using alternative fuel sources both accessible and affordable. Solar cookers are especially beneficial to campers, including RV owners and backpackers.