San Vicente Elementary class creates solar cooker

The main advantage of solar power is that sunlight is free; however, the methods used to convert sunlight into energy are not. A disadvantage of solar electrical panels is that the panels are expensive and they effectively use only 20 percent of the sun’s energy. On the other hand, solar heaters effectively use 70 percent of the sun’s energy and the materials required to make a solar heater are much less. As can be seen from Ms. Brett’s 6th grade class, a solar heater/cooker can be made from common items found in most homes.

Problem: How can the potato or the white rice cook inside the (medium) bottle?

Hypothesis: I think the sun will be reflected to the aluminum foil and then the clear glass, then the sun’s reflection will transfer to the (medium) bottle. And it could become an oven. By 20 to 25 minutes the potato or the white rice will be cooked.

Procedure

Main box with aluminum foil
Measure the box and layout
Make the exact measurement of the box and start cutting
Cut the carton to the square measurement
Insert the carton to the main box
Insert the carton to the main box by down right position, and parallel installations
Glue aluminum foil to the carton
Reflector carton with aluminum foil
Glue the aluminum foil to the reflector carton
Install wood base with paint

Materials

Carton box 11 ½” X 12”
Aluminum foil 37.5 sq. ft.
Construction paper
Clear glass 11 ½” X 11”
X ½” X 1/8”
Bottle (medium)
Metal stud 11 ½” X 6” X 1/6”
Small piece of cloth
Small hook
Knife, cutter, and scissors

See http://solarcooking.org/kerr.htm#INTRODUCTION for information used for this project.

Solar cooker

The sun’s short-wave rays cross the two aluminum or glass walls without losing energy. In touching the internal walls of the cooker that are covered with a non-toxic paint, they are transformed into heat rays that can no longer cross the glass walls. This creates and energy trap that allows us to cook or heat meals.

Figure 8 is a diagram containing three solar ovens, each with a reflector at a different angle. I will define the “reflector angle” as the smallest angle the reflector makes with the plane of the oven window while the reflector surface is exposed to the sun.

Oven A has a reflector angle of 90 degrees. At this angle, the reflector surface does not engage the sun, so it cannot increase the sunlight falling on the box-oven window. It is clear that an angle greater than 90 degrees will cause the reflector to shade the window, obviously not what we want.

Oven C has a reflector angle of 45 degrees; none of the sunlight reaches the oven window because all of the light is reflected parallel to the surface of the window. Also, as the angle becomes smaller than 45 degrees the sunlight is increasingly reflected back toward the sun itself instead of through the window. We don’t want that either.

So, the best angle must be between 45 and 90 degrees. Oven B has a reflector angle of about 60 degrees.

Conclusion: This project proves that solar energy can generate power that will help us conserve consumption of fuel or gas.