Solar Energy

Historical context and evolution.

Throughout the history, our star king the Sun has been an important element in the evolution and development of life from the Mesopotamians to our days. The ancient primitives harnessed the energy coming from the Sun, without having any knowledge, as we know today.

Some civilizations like the Egyptians venerated the Sun, attributing to him a god given its importance, Ra. The Romans used the energy of the sun to heat their homes by storing the heat in the windows.

Others have contributed in an important way, taking the benefits that our star brings. Some of them are:

Archimedes developed mirrors to concentrate solar radiation at one point, and thus be able to eliminate enemy ships. This idea, continued to be used in later centuries in the burning of trees and metal smelting.

Lavoisier in 1972, designed and manufactured the solar furnace, which consisted of two lenses that concentrated all the energy coming from the Sun in one focus, allowing to reach high temperatures for metal casting.

In 1874 Charles Wilson designed and directed an installation for the distillation of marine water in the Atacama Desert, which allowed to desalinate a capacity of 22.500 liters daily.

But, some of these historical characters went further into the study of solar energy. Its motivation was based on the development of energy generation to reduce energy consumption due to population growth.

In 1838, Alexandre Edmond Becquerel was the first in discovering the photovoltaic effect when practicing with his electrolyte battery, he realized that by exposing it directly to the Sun, the current was increasing.

In 1953, Calvin Fuller, Gerald Pearson and Darix Chapin discovered the solar cell of Silicon (Si), which will be important in the future of the history of solar energy.

These small advances led to the initiation of solar photovoltaic energy, although their use decreased due to the low cost of fossil fuels and the increased use of nonrenewable energies.

Resurfaces in the 1970s due to the increase in fuel prices. But, really, it radically changed in the early 1990s with the Gulf War.

Types of solar energy and applications.

As the human has been discovered great applications with the use of solar energy, it has been classified with the criterion of its use by transformations (active solar energy) or directly (passive solar energy).

•  Passive solar energy is the oldest, since it consists in taking advantage of solar rays. An example in the antiquity was the construction of large windows in its monuments to have lighting during the day.

•  Within the active solar energy, we can differentiate between solar photovoltaics (the one that we can transform by solar panels, the direct current of the sun into alternating current for the network). And solar thermal (that takes advantage of the water heating to generate steam and generate electricity by the movement of turbines).

Some applications of the use of solar energy, focus on generating electricity, but it is used not only for this purpose, but also for water heaters, for night lighting through the accumulation of daytime energy, and although it is planned for the use of transport. The most common instrument is the installation of solar panels for the home, to save on the light bill.

Solar panels are composed by numerous cells (photovoltaic cells) of crystalline silicon or gallium arsenide, semiconductor materials. When photons from sunlight strike these cells, some are absorbed by such material. These generate a movement of charges through the semiconductor generating electricity (an electrical circuit).

To use this direct current to our electronic devices, an inverter is necessary to transform the direct current to alternating one.

There are issues that are taken into account in its application, so it is necessary to keep in mind the advantages and disadvantages of solar energy. These are:

Advantages:

• It is a type of clean energy

• It is an energy that comes from an almost inexhaustible source, due to the long duration of its life.

• It is one of the most economical renewable energies available.

• It is an independent energy, because it reaches all parts of the world, against the tidal wave.

• Easy Maintenance.

Disadvantages:

• In order to supply this type of energy, it is necessary large areas to carry out such installation of panels.

Need hours of sunlight. There are countries where implantation would not be effective due to the few hours of sunlight.

• The manufacture of photovoltaic cells requires the need for polluting energies. (Not Renewable)

In the not too distant future solar energy is expected to be competitive with energies called pollutants. But in order to do this, we must continue to rely on study and development in this field with all the means, since it is a free and clean source. There will be drawbacks such as fluctuations in solar radiation due to stations, usage policies, etc. But, as a result, we will be able to live on a cleaner planet and without the need to exhaust the resources it provides.

Bibliography:

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