SOLAR ENERGY TUTORIAL
Welcome to the solar energy tutorial. This tutorial will describe the solar energy resource and explain how it can be used. Also, the technology for the utilization of the solar resource will be explained. Finally, some case histories of solar applications will be discussed.
The Sun As A Resource
At first, the sun may appear as a never-ending resource for us. The life expectancy of the sun is many magnitudes greater than our own lives so the sun seems almost incomprehensible. Also, because of the sun's immense size, the amount of energy it could produce may seem limitless.
This, however, is not the case. Less than half of the solar radiation that reaches the atmosphere even reaches the surface. Of the total energy incident on the earth's atmosphere, twenty-five percent is reflected by the atmosphere, and nine percent is reflected by clouds, sending thirty-four percent back into space. In addition, ten percent is absorbed by clouds, and nine percent is absorbed by the atmosphere. This means that of the 1353W/m2 that reach the outside of the atmosphere, only 400-500W/m2 actually reach the earth's surface.
Solar Energy Basics
This lessontakes you through some of the basics of solar energy.
Ways of Using Solar Energy
There are three main ways that we can harvest power produced by the sun.
1. Harvesting solar energy directly for space heating.
2. Use it to heat run a steam generator to produce electricity.
In this process the solar energy is concentrated so that it can create enough heat to operate a steam generator, which in turn produces electricity.
3. Use it to operate photovoltaic cells.
Gentle Solar Basics Tutorial
This tutorial takes you through some more basic concepts, but it goes into more detail.
Photovoltaic Cells
Photovoltaic cells are based on semi-conductor physics. They are designed in such a manner that allows them to directly convert the sun's incident energy into electricity. Thephotovoltaic cell tutorial will take you through this in greater detail.
Use in large scale production
Photovoltaic cells are probably the best answer the sun has to offer to the problem of creating large-scale, renewable energy resources.
Analysis of Large Scale Production
Case Studies and Examples
Solar Cooking
Solar Car
A LeCar was transformed into a solar powered car in an effort to explore solar energy uses in Pennsylvania. It was designed for people who needed to commute to work. The problem with this car was that it could only store about thirty-five miles worth of energy. This meant that the car needs to be recharged while the commuter was at work. Conditions conducive to charging are unreliable so this idea didn't get very far.
Solar Fish Tank
It was attempted to use a photovoltaic cell powered compressor to operate a fish tank. Because a continuous source of power is necessary for the compressor, the extra electricity is stored in the form of hydrogen. When the electricity is needed, the hydrogen is drawn along with oxygen from storage tanks and allowed to recombine. This produces a current. A personal computer is used to operate and monitor the system. There is risk involved, however, with this seemingly ingenious system. If the hydrogen and oxygen combined out of control, it could lead to an explosion. Also, hydrogen is a very corrosive material, and the pipes and storage containers would have to be very carefully (and expensively) designed. There is, however, a relatively large amount of energy stored in a kilogram of hydrogen compared to a similar amount of either gasoline or batteries. Therefore, if the bugs can be eliminated, this idea may be applicable in other situations.
Conclusion
These case histories and examples show that solar energy can be harvested in many different ways and for many uses. Many of these, however, are still on the experimental stage. Until more research time and money can be devoted to developing the possibilities, solar energy cannot be counted on as our savior.