Solar to Electrical Energy
Initial brainstorm and construction:
Living in Qatar, I realised the abundance of solar energy in the Middle Eastern countries. I wished to spread awareness about this under utilized clean energy through inter school science fairs in 2010. So, when my friends and I created a project on clean energy sources, I added my solar model to the other projects on Ocean thermal energy conversions and
Biomass energy sources that we built together.
I collected an undersized solar panel, light bulb, LED lights and an electric motor from a local recycle store. With the help of a carpenter, I created a miniature village which had the house lights as the LEDs and the electric motor as a fan. The light bulb played role of a mini sun (just wanted a powerful light source) for indoor demonstrations of our project.
AIM: To apply my knowledge, of physical sciences, attained from my school resources about :
1)Solar energy
2)Solar panel
3)Photovoltaic effect
4)Solar powered gadgets
and demonstrate the conversion of solar energy to electrical energy.
APPARATUS:
An small solar panel, Light Emitting Diodes, a light bulb, an electric motor and 2 slabs of cardboard.
BLOCK DIAGRAM:
FIGURE-1
In our project, the source of light is the bulb which plays the role of a symbolic sun, for indoor demonstrations. The electric current, in our case, lights the LEDs and is used to rotate the fins of our electric motor.
PROCEDURE:
1. Connect the light bulb to an electrical power point. (This step is only taken for indoor presentations).
2. Place the solar panel under the beam of the light bulb. The rechargeable batteries (secondary cells) get charged inside the solar box.
3. Connect the output of the solar panel to the Light Emitting Diodes and the electric motor, using a small distribution chip.
4. The LEDs get illuminated and the motor fins rotate when the batteries discharge inside.
5. In this way we are actually generating an electrical output of around 1.5 Volts from a solar energy input.
Working Principle:
1) Solar energy :
Solar energy, radiant light and heat from the sun, is harnessed using a range of ever-evolving technologies such as solar heating, solar photovoltaic, solar thermal electricity, solar architecture and artificial photosynthesis. Solar energy has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available renewable energy on earth. Only a minuscule fraction of the available solar energy is used.
2) Solar panel:
Solar panel or photovoltaic panel is a packaged interconnected assembly of solar cells, also known as photovoltaic cells. The solar panel can be used as a component of a larger photovoltaic system to generate and supply electricity in commercial and residential applications. Silicon cells are quite widely used in most solar power plants. These types of cells contain two layers, positive layer and negative layer just like in most semiconductors. Positive layer exist on the top side whereas negative layer exists on button. Electric field is created with in these layers. Photons from sun light strikes on semiconductors in result electrons are released, electrons are electric charge. This electricity is transferred as direct current (DC) in panel.
FIGURE-2
A solar panel (also solar module, photovoltaic module or photovoltaic panel) is a packaged, connected assembly of photovoltaic cells. The solar panel can be used as a component of a larger photovoltaic system to generate and supply electricity in commercial and residential applications. Each panel is rated by its DC output power under standard test conditions, and typically ranges from 100 to 320 watts.
Solar panels use light energy (photons) from the sun to generate electricity through the photovoltaic effect. The majority of modules use wafer-based crystalline silicon cells or thin-film cells based on cadmium telluride or silicon. The structural (load carrying) member of a module can either be the top layer or the back layer. Cells must also be protected from mechanical damage and moisture.
Bypass diodes may be incorporated or used externally, in case of partial panel shading, to maximize the output of panel sections still illuminated. The p-n junctions of mono-crystalline silicon cells may have adequate reverse voltage characteristics to prevent damaging panel section reverse current. Reverse currents could lead to overheating of shaded cells. Solar cells become less efficient at higher temperatures and installers try to provide good ventilation behind solar panels
The photovoltaic effect is the creation of voltage or electric current in a material upon exposure to light. The standard photovoltaic effect is directly related to the photoelectric effect, though they are different processes. When the sunlight or any other light is incident upon a material surface, the electrons present in the valence band absorb energy and, being excited, jump to the conduction band and become free. These highly excited, non-thermal electrons diffuse, and some reach a junction where they are accelerated into a different material by a built-in potential (Galvani potential). This generates an electromotive force, and thus some of the light energy is converted into electric energy
Conclusion:
The conversion of solar energy to electrical energy has been successfully demonstrated.
References:
1) Definition of solar energy and applications retrieved from- http://en.wikipedia.org/wiki/Solar_energy
2)Definition of solar panel and applications retrieved from- http://en.wikipedia.org/wiki/Solar_panel
3) Figure 2 retrieved from- http://fahysolar.blogspot.com/2013/06/solar-panel-diagram.html