NOTE: this page is under construction.
An Introduction to the Parabolic Solar Cooker
The Paraboloid Shape
The paraboloid is an interesting shape with some amazing qualities. It has the power to concentrate light, electronic waves, sound, etc. to it's focus at the center.
A Brief History
Parabolic cookers used for centuries now...
My Parabolic Solar Cooker
A Brief Description
At first, i was open to anything to construct the solar cooker. i was thinking about constructing my paraboloid out of cobb and then sticking small pieces of glass into it as i've seen others do. However, it takes a lot of time to collect the cobb materials and build a paraboloid out of it, let alone one whos' focus was accurate. But while rummaging around Arcata Scrap and Salvage one day, i came across an old mesh satellite dish and i knew i had found my cooker. Bart and i hauled it to the Bike Library where my cooker began to take shape.
Location and Help
Most of the construction and testing took place at the Arcata Bike Library with the help of Bart Orlando. However, i did most of the cutting of the sheet metal at the HSU sculpture lab.
Materials Used
- Satellite dish
- Sheet aluminum
- Conduit piping
- A bike rim
- Aluminum rivets
- Nuts & bolts
Method
The basic idea was to use a satellite dish and rivet sheet aluminum to it. This is because a satellite dish is already a paraboloid shape with a pretty exact focus. The sheet aluminum was to be cut into triangular pieces and then be drilled in 3-5 places for the rivets. They would conform to the shape of the paraboloid and not lessen the integrity of the focal point. We wanted the aluminum to be as exact as possible to ensure that it would reflect enough light to fry some potatoes. i wanted to do more than boil water with my cooker. The hot plate grill was to be constructed out of conduit and bike rims. We would flatten the ends for easier attachment to the center pipe and rims, and then bolt it all together. We decided that a gimble would be the best for this project, so that we could move the pan (or pot) in any direction necessary to get the most sunlight. This is a more difficult design, but it gives the dish more freedom and a higher heating capacity.
Final Construction
We started by disassembling the focal point of the dish. It was an akward pole sticking out of the center, but we found that we could remove it by loosening a bolt at the base. We also had to remove a bunch of miscellaneous pipes and widgets sticking out the back side of the dish. But after that, the dish was ready for action.
The next step was to construct a hot plate grill. We decided that it would be best if we used conduit to form a "v" shape and then fit in a few bike rims for the hot plate. We had to flatten the ends of the conduit and make sure that they were the right size for the focus. This was done using a clamp and we were able to bend both pieces of conduit at the same time. It was time to drill some holes. We discovered that the center pipe we wanted to use was slightly shorter than we wanted, but being that we were in such a resourceful area, we rummaged around and found a pipe that was the perfect size and width. The next step was to drill holes in the flattened sides of the conduit and our newly-found pipe and fit the pieces together. They fit quite nicely.
Bart had aquired a bunch of sheet metal that he had wanted to use on a previous project, but decided that my dish could use them. There wasn't quite enough cut pieces to cover the entire surface area of the dish and i had to take some scrap sheet aluminum to the HSU sculpture lab to cut them into a triangular shape. After they had been cut, they needed to be prepared for riveting. It took about a half an hour to drill holes in all of the pieces and they were quickly ready to be fastened to the dish. While putting the pieces in place, we noticed that the holes we had drilled did not always match the pattern of the mesh, and there were areas where the mesh was covered with pieces of solid metal. These areas had to be dealt with differently. In some areas, we were able to drill holes through the metal for the rivets, and in others, we devised a way of using a thin wire to attach the pieces. i used a paperclip i found on the ground and stuck it through the hole and then through the mesh slightly above the triangle. Using pliers, i twisted the ends of the paperclip to form a tight grasp on the metal; it worked quite well.