Solar Power Cells

Calculators that run on solar power aren’t new. But before solar cells were used in consumer devices like calculators, they were used in space. Today, more and more uses are being developed for solar power cells and how they work is intriguing.

Photovoltaic cells are made from a semiconductor, often silicon, which gathers energy from the sun.  When the light hits the semiconductor, electrons break loose and are pushed in the same direction forming an electric current.   To harness this electricity, photovoltaic cells are connected to a circuit which begins at the top, sends energy through the appliance, and back toward the contacts at the bottom of the cell.

Very little movement of electrons is possible when silicon is in its natural crystalline state, so the silicon is actually impure.  Individual silicon atoms each possess four locations to which electrons can be bonded and so are relatively unstable.  But each atom typically joins to others through the sharing of electrons in their outer valances.

Silicon is not as conductive in its original form, so to get the most energy from the solar power cells, N-type silicon is used.  It is created from a reaction combining silicon with phosphorus.  The result, a free electron is available for each phosphorus atom joining with the 5 outer ring silicon electrons.

Doping silicon with boron results in P-type silicon.  The outer shell of the boron atoms have only three electrons, leaving a “hole”, which is a place into which  an electron can move.  In photovoltaic cells, one combines P-type silicon with N-type silicon.

Two different types to silicon need to be set up side by side.  The first thing that will happen is the holes and electrons begin to fill in at the shared border.  You will know when equilibrium is reached once the electrons can’t interact in that way anymore.  The two halves will separate, creating an electric field.  At that time, it will be easy for the electrons to flow from the positive side to the negative side.  However, the electrons that are already in the negative can’t flow back to the positive side.  You’ve created a one-way flow of electrons.

Photons consist of energy units from the sun, and they make energy by making contact with the atoms of the solar cell and freeing holes and electrons.  This continues the movement of electrons between holes and establishes current.  Voltage results from the field created at the site of the P-type and N-type silicon junction.

Harnessing the energy from the sun through photovoltaic solar power cells is still essentially in its infancy.  Both commercial and residential settings are seeing the benefits of using the power of these cells.  Anyone willing to do a little research and take a little time can grasp the concept of photovoltaic cells.  Using the power of the sun through photovoltaic cells makes solar power a real possibility.

Direct Solar Power Vs Indirect Solar Power

Solar power is a great renewable resource, but it’s uses have barely been explored.  While indirect solar power has been used since the beginning of man, the uses of direct solar power have barely been tapped.

The sun must make one change to make direct solar power into a usable form.  Direct solar power can come in many forms.  It is   produced when photovoltaic cells receive sun energy and convert it into electricity. This occurs in one step, thus it is “direct”.

Fiber optic cables are a source of solar power, when they are mounted outside so they can use the suns energy to light interiors. This typically is used as an extra source of lighting and not as the sole source.

The solar thermal collector is also a  type of direct solar power. It produces energy by absorbing sunlight.  The surface of the collector gets warm and the resulting heat is made into energy and  used in a fluid circuit.

One interesting use of direct solar power is with spacecrafts.   They use it directly with the solar sail in the craft that collects sunlight to power the craft.  This is a great use as a spacecraft doesn’t have a lot of room to carry fuel and it gets a lot of sun up there above the clouds.

Indirect solar power, on the other hand,  has been extensively used for millions of years.  This is the type of solar power that changes more than once to become usable energy.  This can be seen as the result of the sun’s effects naturally on the world.  Man may use the energy but the sun’s power has been concentrated.

Common crops, either grown on purpose or in the wild are an example of indirect solar power.  First off, the plants apply photosynthesis to conver the suns light into energy.  Then the plant themselves is eaten to produce energy, or in the case of tree limbs burned in a fire to produce energy.  Plants can even be turned into bio fuels which is a great example of an indirect usage of the sun to produce energy.

Fossil fuels like coal and oil are forms of indirect solar power.  Before they were turned into coal or oil, the living things that made them used the sun’s energy to survive.  These fuels are not renewable, and are not thought of as solar power.

Wind turbines and hydroelectric dams are also affected by the suns energy.  As the sun makes things warmer, the winds change as does the overall weather.  Indirect solar power is used all the time, but the problem is that it is not renewable.  When direct solar power, however, is used as much as indirect, then energy usage will be much different from what we know now.