Solar Power Essay
February 15, 2010
The heat of the sun is about equivalent to burning a billion trillion tons of coal an hour. Even though only a small fraction of that heat ever reaches the earth it is still more then enough to power the whole world.
People seemed to realize the importance of the sun around 30,000 BC. This was when people first started planting crops of wheat. They realized plants did better when planted in the sun over the shade. This caused them to worship the sun as a God. Many cultures built large and extravagant temples to worship the sun in. Other cultures built places to observe the sun in, such as Stonehenge in England.
Different Types of Solar Panels
There are three main types of solar panels. They are flat plate collectors, focusing collectors, and solar cells.
The first kind is a flat plate collector. Flat plate collectors are fastened on the top of the roof of a house. They usually either heat the house or its water. A flat plate collector consists of a black rectangular frame, two or three sheets of glass, and copper plumbing. A flat plat collector uses the greenhouse affect. The sunrays go through the glass but can’t get out through the glass. The sunrays heat the water-filled copper tubes. Then the water is used to heat the home or water.
Another type of a solar panel is a focusing collector. They consist of a mirror or mirrors which are focused in one spot. Some focusing collectors are solar furnaces, parabolic dishes and troughs and power towers.
The first type is a solar furnace. A solar furnace consists of many mirrors that are aimed at a large curved mirror that is aimed at a large steel building. This building can get as hot as 5,790 F. Scientists use solar furnaces to run experiments to see how certain materials react to extreme heats. They are also used industrially to melt metals.
The next kind of focusing collector is a parabolic trough and dish. A parabolic dish looks just like a satellite dish except the dish part is to reflect the sunrays onto the vocal point which is filled with oil. The heated oil is used to produce steam to turn a turbine. A parabolic trough uses the same principles as a parabolic dish. The only differences are how they look, the mirror is shaped like a large feeding trough and the vocal point is an oil filled tube. These are used for either commercial such as in a power plant.
The last focusing collector is a power tower. A power tower has many mirrors all focused on a large tower. This tower gets extremely hot. The tower is filled with oil. When the oil is heated it is piped to a power plant where it is used to produce steam that turns a turbine. These are used for power plants.
The final type of solar panel is a solar cell. A solar cell usually consists of two layers of silicon that produce an electric charge which is picked up by wires that are laid across the silicon. Solar cells can be used for anything from powering an isolated phone booth to a whole city or even an airplane.
Solar Energy started around 30,000 BC when people first desalinized water, or took the salt out of salt water. In 1,000 BC a king had the water in his castle heated by the sun. Romans passively heated their homes in about 100 AD. In a passive solar home there is no machinery, but there are windows and the floors and windows are made of materials that absorbs heat, like adobe.
Solar heating was not used until the late sixteenth century when European scientists started experimenting with the power of the sun. In 1714 many people worked together to create the world’s first solar furnace. In 1720 a Swiss scientist, Horace Benedict de Sasure, built the first modern solar water heater. In 1774 Antoine Lavoiser made a printing press powered by the sun. Later in 1880 in Chile a solar desalinization system was made. Also in 1880 the first solar cells were made. Solar cells when originally made they were very expensive and were not available on the market. Now you can buy solar cells cheaply.
Today we use solar power to do many things. We use solar power for everything from calculators to large power plants that can power large cities.
Most common solar power is used for small things. Many calculators are run by solar cells so they will never run out of batteries. Some watches run on solar cells, too. Also you can buy radios that run on solar cells.
There are also many big things that run on solar power. Almost all satellites run on solar power, because otherwise they would run out of power. There are also large desalinization plants that use solar power in places where there is little or no fresh water. There are solar furnaces in many countries. Solar power is also used commercially and residentially. It is also used for many forms of transportation, but these are all in the experimental stage now. Solar powered cars may soon come out.
Indirect Solar Power
There are three forms of indirect solar power. They are wind power, waterpower, and ocean thermal energy. You might think these have nothing to do with each other or solar power but they do, in some way they each use the sun.
The first type is wind power. The reason this is a form of solar energy is because the sun heats the air that creates air currents, or wind. The wind turns propellers that turn turbines which creates electricity. Wind power has been used for a very long time. Places in Europe like the Netherlands have had windmills since the Middle Ages. Though these windmills were used to pump water or to grind grain.
The next form is waterpower. This is considered solar power because of the hydrologic cycle. The hydrologic cycle is water evaporating from bodies of water then coming back to earth in different places. This allows them to go back through dams to produce electricity. The water turns turbines, which then create electricity. Waterpower is also an old process it used to be used at sawmills and to grind down grain.
The last kind of indirect solar power is ocean thermal energy. Ocean thermal energy is a power plant that uses the difference between the surface temperature and the temperature of the bottom of the ocean to produce electricity. When the cool water meets the hot water it produces steam that turns a turbine to produce electricity. The electricity is then sent to land through wires. This is solar power because the sun heats it.
The Solar Future
Today the use of solar power is very limited. Today we use very little active solar heating. Though in the future many more homes will be solar heated. More homes will have passive solar heating. Scientists want to make a satellite that will orbit over one place. This satellite would have giant wings made of solar power, this satellite would beam electricity down to earth. This would allow the solar cells not to be obstructed by clouds or buildings. Also ground solar power plants are predicted to be used more frequently. Another thing predicted to be popular is solar powered cars. The drawback of these cars is the fact that you can only travel at high speeds for a short time and they don’t work on cloudy days. Solar powered cars are only used for racing and experiments now.
I think if there is another oil crisis there will be much more use of solar power. Solar power will be given more federal funding which will increase studies. The increased studies will make solar power cheaper and more efficient. This will make solar power more available on the market.
I think that solar power is a good alternative energy source. It has many advantages over fossil fuels. One is that the sun is free and does not have to be bought like other fuels. It also doesn’t hurt the environment and it is a renewable energy source. There are a few drawbacks to solar power. One is that it can be expensive to make and can be hard to use on cloudy days. Solar power is also difficult and expensive to store. Another bad thing is that silicon the material that solar cells are made of can be hard to find.
If there is another energy crisis like the United States experienced in the 1970’s, solar power will be greatly increased. Federal funding will be increased to promote the studies of solar power. This will make solar power more efficient which will cause it to become cheaper.
After the last energy crisis, most federal funding was decreased or stopped. This is very unfortunate because solar power would be far more advanced with more funding.
Hypothesis: I think that some of the water will get into the inner bowl, this water will be fresh and the salt will still be in the outer bowl. I think that it will work better on sunny days than on cloudy days.
Procedure: First I mixed two cups of water with two tablespoons of salt. I put the salt water into a large aluminum bowl. Then I put a small cereal bowl into the large bowl. I covered the large bowl with plastic wrap to keep the water from evaporating out of the bowl. After the bowl was covered I put a weight on the plastic wrap so the water would drip into the cereal bowl after it evaporated. I started this experiment at seven o’clock and then took observations at three and eight; I took all three observations for five days.
Observations: On the first day at three there was some water on the plastic wrap after it had evaporated. At eight most of the water on the plastic wrap had dripped into the inner bowl. That day it was sunny. At seven the next there was a little more water in the small bowl. At three that day there was a little on the plastic wrap. At eight the little water on the plastic water had gone into the cereal bowl. It was cloudy that day. In the morning at seven there was no change from the night. At three that day there was a little water on the plastic wrap. At eight most of the water on the plastic wrap was in the cereal bowl. On the fourth day at seven the rest of the water was in the cereal bowl. At three the rest of there was a little on the plastic wrap. That night at eight the rest of the water on the plastic wrap was in the cereal bowl. It was partly cloudy that day. On the last day in the morning there was no change from the night before. At three there was a little more water on the plastic wrap. The water on the plastic wrap was in the small bowl. It was partly cloudy that day.
Conclusion: My hypothesis was correct, but I thought more water would be purified then actual did get purified. The water in the cereal bowl had no salt in it. This experiment proves that solar power works and that it works better with no clouds than with clouds.