The Sun basic source of energy

The solar radiation intercepted by the Earth constitutes the main source of renewable energy within our reach. The amount of solar energy captured by the Earth annually is approximately 5.4 x 1024 J. A figure that represents 4,500 times the energy consumed.

The Sun basic source of energy. The Earth receives electromagnetic radiation from the Sun. And sends it back to space an amount of heat equal to the incident radiation. Therefore, the use of solar radiation is nothing other than its conversion into useful energy for humanity. However, the net result of such exploitation is the same as if there had been no interference in the process of receding into space. Well, there has only been a gap or delay in this process. As a result of human arrangement or part of natural processes.

Solar energy reaches the Earth’s surface in two different ways:

  • Affecting objects illuminated by the Sun. Called direct radiation.
  • By reflection of solar radiation absorbed by the air and atmospheric dust. called diffuse radiation.

The first is usable directly. While photovoltaic cells take advantage of the second.

Solar energy is captured through photovoltaic cells

Despite its abundance, the use of solar energy is mainly conditioned by three aspects:

  • The intensity of solar radiation received by the Earth.
  • The daily and annual cycles to which it is subjected.
  • The weather conditions of each place.

The beneficial use of solar radiation as a source of energy is directly linked to the geographical location of the place chosen to take advantage of it. And of temporal variations.

In general, the term solar radiation refers to the values of solar irradiation. That is, the amount of energy received per unit area in a given time.

The Sun basic source of energy

These values normally express the energy that comes from direct radiation from the solar disk and diffuse radiation. Which, scattered through the atmosphere, comes from the rest of the sky. The proportion between direct and diffuse radiation varies according to climatic conditions. Just as, on cloudy days, diffuse radiation can be canceled out.

On the one hand, solar radiation is a form of low-concentration energy. Since outside the atmosphere the intensity of solar radiation received by the Earth ranges between approximately 1,300 and 1,400 W/m2.

the sun is the primary source of energy for ecosystems

The Sun basic source of energy. On the other hand, losses to the atmosphere due to reflection, absorption and scattering reduce this value by around 30%. With a radiation intensity from the Earth of around 1,000 W/m2.

These values may vary depending on weather conditions. For example, on a day without sun, the radiation intensity values can be reduced to 150 or 50 W/m2.

This low radiation density and the negative effect of certain weather conditions make it necessary to use large collection surfaces. In case you want to achieve significant values of energy use.

energy sources

Solar radiation

The incident radiation on a surface is usually measured through solarimeters. From time series of radiation measurements, maps of solar radiation are prepared. By which estimates of incident solar radiation on certain territories can be made. And for limited periods of time. Simply by multiplying the values read on the map by the surface area of the area. As well as, for the given period of time.

Also from series of measurements manuals are made that gather tables of radiation values on surfaces with a certain orientation. And tilt for different microclimates.

Through these estimates of the incident solar radiation on a flat surface with a given orientation and inclination are obtained.

why the sun is important

The most usual way to represent the temporal variations of incident solar radiation on a surface. It is from the frequency distributions of daily values. And the power duration curves. And that they are nothing more than the accumulation of the values of the frequency distributions.


Regarding the use of solar energy, we can speak of two types of systems:

  • Those that convert solar radiation into electricity using photovoltaic technology.
  • Those used for the production of thermal energy.

The Sun basic source of energy. The possibility of making more global use of solar radiation should also be considered.

Natural light and the specific weather conditions of each location, in the construction of buildings through what has been called bioclimatic architecture.

Photovoltaic solar energy is captured through photovoltaic cells. Since they are the ones that convert solar rays into electrical energy. This method of harnessing solar energy is the most recently developed among the different types of renewable energy.

advantages of solar energy

And it has a very wide field of application. From the use in consumer products, such as watches and calculators, to the electrification of areas without conventional supply. Such as isolated houses or agricultural and livestock facilities, passing through land and maritime signaling. And communications or public lighting.

The direct transformation of solar energy into electricity through photovoltaic conversion has clear advantages.

How is its simplicity, autonomy, reliability and operability. In addition, they are related to the high energy quantity of the electricity produced. As well as the absence of environmental impact and noise in the energy process.

uses of solar energy

In spite of everything, for the moment, the current participation of photovoltaic energy in the European energy balance is still marginal. Its investment cost is currently higher than that of conventional alternatives. Although it experiences a rapid reduction. And it is expected that in the coming years the European market will grow at a rate of between 15 and 25% per year. And we want the world to do it too.

Solar thermal energy can be actively obtained through specific elements. Through which a fluid circulates that absorbs the energy radiated from the Sun. Or passively, through a series of applications known as bioclimatism.

In the latter case, its use is related to an aspect that is becoming very popular:

The Sun basic source of energy. Optimizing building design to reduce additional heating and cooling needs as much as possible. This application can be very useful in homes, but also in swimming pools, hotels and sports centers.

The use of active system is mainly oriented to cover part of the thermal needs of a building. How the production of domestic hot water and heating. This set of applications is what is called low temperature active solar energy.

In recent years, solar thermal energy has achieved a degree of maturity. Since it makes it a good option technically and economically. In this sense, the application of solar energy to produce domestic hot water is one of the possibilities that offers the most attractive profitability. The latest advances and lines of research have focused on improving materials and control elements. As well as in the regulation and monitoring of the operation of the facilities.

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