With the world’s energy needs growing day by day, it’s about time to store the free, safe, clean and abundant solar energy you find everywhere. Solar energy provides about 1000 watts of power per square meter of Earth’s surface it hits on a sunny day.
Moreover, did you know that the total solar energy that reaches earth in two hours can provide for entire world’s energy consumption if stored and harnessed properly? This is why it’s important to know how to store energy from the sun.
Using solar cells
The first thing that comes to mind is storing solar energy in solar cells or photovoltaics. They are non-polluting and long-lasting devices which convert about 10-15% of solar energy into usable energy.
Another means of getting electricity from solar energy is by intensely focusing sunlight into a small area using mirrors or lenses to heat water and create steam. This high-pressure steam generates electricity when passed through a turbine.
The electricity generated by solar cells and steam-driven turbines can be stored in batteries or supercapacitors to be used when cloudy or at night. It’s also possible to store the thermal energy of sunlight in the heat capacity of molten salt at high temperatures. Heat is transferred from the molten salt to water using a heat exchanger to generate steam and drive a turbine when electricity is needed.
It’s also possible to harness and store solar energy by using sunlight to produce fuels. For example, it’s possible to split water into hydrogen and oxygen using a photoelectrochemical cell and sunlight. The gases are later recombined to generate electricity in a fuel cell.
Of course, sunlight can also directly heat a tank of water placed outside the house and this heated water can be used for showering and bathing. This is quite common in developing countries.
And … you can also use solar energy directly as we show in the solar hot dog cooker project too!
Here are some other fun ways to generate power to do some fun things …
Have you ever heard the phrase “It’s so hot you could cook an egg on the sidewalk”? Have you ever wondered if it was true? With this experiment you can see how the heat (energy) of the sun can be captured and used to cook food.
What you Need:
- Cardboard pizza box.
- Box cutter or scissors.
- Aluminum foil.
- Clear packing tape.
- Cellophane (plastic wrap) or a heavy duty freezer bag.
- Black construction paper.
- Ruler or wooden spoon
Cut a flap in the top of the pizza box. Make sure you only cut on three sides creating an attached flap. Leave about 1” between the flap and the edge of the lid of the box. Fold the flap up so it stands up when the lid is closed.
Cover the underside of the flap with aluminum foil. Try to keep the foil as smooth as possible so it reflects the sun well.
Using the plastic wrap or the bag create a “window” in the hole left behind by the flap. Fasten the wrap to the underside of the lid with clear packing tape. Repeat this process twice to create two layers of wrap.
Now you will line the bottom and sides of your oven with black construction paper.
Use the newspaper to insulate the sides of the oven by bundling it into roughly the shape of a paper towel role and lining the inside edges with it.
The best hours to use your solar oven are going to be from 11 a.m. to 3 p.m. when the sun is at the highest point in the sky. Take your oven to a sunny spot and adjust the flap until the most possible light is reflecting into the oven.
Choose the food you want to cook, perhaps something out of the recipes provided or you can try something else that you think will work well.
Make sure that whatever you are cooking is placed on a clear glass plate or cooking dish. This will ensure that the heat from the sun reaches all parts of the food, not just the top.
Place the thermometer in the oven so you can monitor the temperature.
Once your food has cooked thoroughly use oven mitts or potholders to remove the glass cooking dish.
Understanding how it works:
The heat generated by the sun’s rays is trapped inside your oven, it begins to get very hot much like a traditional oven would. Ovens like this are called collector boxes, because they collect the suns energy. A well designed solar oven can reach temperatures of up to 200 degrees, allowing you to cook almost anything whether it is hotdogs or nachos and cheese. If you don’t want to wait for the food to actually cook you can also use the solar oven to re-heat leftovers, since they are already cooked you do not have to wait for them to heat up to as high a temperature. Make sure that anything you cook in your oven is cooked entirely before you eat it.
Building a solar cooker is fun but want to try something bigger? Take a look at this project: http://how-things-work-science-projects.com/learn-build-enti…solar-power-grid/
This is a great project to do in science class or as a project with your kids. You usually see kids outside with lemonade stands and Kool-Aid stands, but you don’t see a hot dog stand very often! Even better, there’s no fire used. All your kids will need is good strong sunlight. If you decide to use this project in science class, there’s no better way to get your kids attention than teaching them about solar energy with food!
Our project will be done with a single box, so it won’t look like the commercial solar cooker above, but the project is very simple and doesn’t cost much to accomplish. Never mind that your kids will wonder why there are hot dog buns, ketchup, and mustard on your science table!
Here’s what you’ll need:
- A cardboard box
- Poster board
- Hot dogs
- Tin foil
- A utility or Exacto knife
- A metal coat hanger
- Wire cutters
- Needle nose pliers
- Box tape
Notes: If you are using a template for cutting, make sure that all of your boxes are exactly the same size so the templates will fit for all of the boxes. Make sure that your coat hangers are free of any paint!
Step 1: The longer the box you use, the more heat you’ll be able to collect. That being said, choose a long narrow box and a focal length of between 5 and 10 inches. Design a parabolic curve on the longer sides of the box. You can cut out a curvature template for the boxes that allows the kids to trace. Make sure the curve is well centered and that the corners of your template reach the corners of the side of the box.
Step 2: Cut out the sides of the box on the template line.
Step 3: Cut a piece of poster board that will fit flush with the inside of the box. Again, you may want to have a template ready if you are going to be creating more than one solar cooker.
Step 4: Attach the poster board with box tape starting at the middle on both sides and working your way toward the edges.
Step 5: Apply glue to the top of the poster board and then apply the aluminum foil. Be careful not to crinkle the foil. You want it as smooth and unblemished as possible for it to work properly.
Step 6: Use a couple of pieces of box tape to help anchor the sides. Use the sun to find the focal point of the sun’s rays so that you know exactly where to place your skewer. Putting a dot at each end of the focal point, poke a hole where you’ve placed your dots.
Step 7: Manipulate your coat hanger into a skewer with a hand crank. Thread the coat hanger into one end, skewer your hot dog and then thread the coat hanger through the other end. This setup should allow you to turn the hot dog.
The above is a cooker made out of a single box. Fairly simple to make (and it works) but somewhat limited. So … if you’re interested in a more elaborate design, here are instructions for one that just might burn your hand if you keep it in the focal point too log. Enjoy! … complements of YouTube …
To see just how much cooking you can do with a parabolic style cooker, take a look at these videos. What a remarkable way to capture the sun’s energy! …
And to see the article they came from, see Wikipedia
For other fun projects …
Like this solar cooker? Here is another that might interest you: http://how-things-work-science-projects.com/build-solar-cooker/
Solar power can do big things and little things like this simple cooker: http://how-things-work-science-projects.com/solar-hot-dog-cooker/