Photovoltaic and thermal solar energy

Photovoltaic and thermal solar energy are the most popular ways to harness sunlight for the benefit of human beings, one generates electricity and the other heating and hot water

Photovoltaic and thermal solar energy

The   best known renewable energies within our country are solar thermal and photovoltaic. This fact is not accidental, and is that with the amount of daylight hours that our weather presents, the use grazes the maximum admissible. Which of the two is more advisable? Is there any difference between solar thermal and photovoltaic?

Difference between solar thermal and photovoltaic

Solar thermal energy (or solar thermal)

On the other hand,  solar thermal or solar thermal energy  consists of harnessing the sun’s energy to produce heat that can be used to cook food or to  produce hot water for domestic consumption , whether  hot water (DHW) or heating  or for  electricity production .

It is used above all to heat a fluid that serves for the production of sanitary hot water or heating, for example. But in addition, that thermal energy can be used to generate steam that turns conventional turbines and produces electricity.

Additionally it can be used to power an  absorption refrigeration machine , which uses heat instead of electricity  to produce cold  with which the air in the rooms can be conditioned.

The collectors of solar thermal energy are classified as collectors of low, medium and high temperature:

  • Low temperature collectors . They provide useful heat at temperatures below 65 ° C by means of metallic or non-metallic absorbers for applications such as pool heating, domestic heating of bath water and, in general, for all those industrial activities in which the process heat is not greater 60 ° C, for example pasteurization, textile washing, etc.
  • Medium temperature collectors . They are the devices that concentrate solar radiation to deliver useful heat at a higher temperature, usually between 100 and 300 ° C. In this category we have the stationary concentrators and the parabolic channels, all of them effect the concentration by means of mirrors directed towards a smaller receiver. They have the disadvantage of working only with the direct component of solar radiation, so their use is restricted to areas of high insolation.
  • High temperature collectors . They exist in three different types: the parabolic dish collectors, the new generation of parabolic trough and the central tower systems. They operate at temperatures above 500 ° C and  are used  to generate electricity  ( thermosolar electricity ) and transmit it to the electric grid.

The demand of electrical energy by the world population has made the rise of these last types of solar thermal energy is increasingly accentuated by  increased demand for electricity consumption  and awareness of  energy efficiency . Both take advantage of the sun as a source, but both in management and in operation in response to demand, they are different energies.

As for the storage system, the difference is that while photovoltaic solar energy uses batteries, solar thermal is stored in water tanks.

Two different concepts but with the same purpose: to take advantage of the sun as a source of energy, a clean and inexhaustible energy, valid for any place in the world since in all regions the sun rises, although its radiation is greater or lesser.

Although it is true that the initial investment in this type of energy can be considerable, in a few years it is amortized. And the most important thing: with its use you will not only save on your invoice but you will be contributing to a more sustainable world.

If you are interested in moving to solar energy, at Viesgo we make it easy for you. Go to and find all the information you need. With our simulator you can calculate, in just 1 minute, the cost of your installation, the time in which you have amortized and what you have saved. Do not wait any longer and move to solar.

Photovoltaic energy

In the case of  photovoltaic solar energy , it directly transforms the natural light of the sun into electricity. This is possible thanks to the installation of solar panels, formed by modules that contain photovoltaic cells, whose sheets of semiconductor materials and transparent glass cover let solar radiation pass while also minimizing heat losses.

From the moment that sunlight hits the faces of these cells, an electric current is generated, a process known as the photoelectric effect. Among the applications that have this way of obtaining energy are the feeding of motors and electrical appliances or the discharge to the electrical network.

If the thermal solar energy needs a thermal process, the photovoltaic one needs a chemical process: it consists of the  transformation of radiation of the sun into energy  through a direct electric current that is obtained by the use of semiconductor materials. This transformation into  energy is immediate  thanks to the photovoltaic modules.

The development of this renewable energy far exceeds solar thermal energy: there are a total of 145 GW installed today. This difference has a simple explanation:  self-supply ; Photovoltaic energy systems are recommended to be self-sufficient in electricity. This has led manufacturers to develop  storage systems and modules that are  increasingly accessible and viable for the population.

Surely you know how you get solar energy, through the sun’s radiation, but, did you know that depending on how you take advantage of this you can produce electricity or heat?

That is why we distinguish between two types of technologies: photovoltaic solar energy and solar thermal or solar thermal energy, whose operation is totally different. In this post we explain what each one consists of.

Read more: what is photovoltaic solar energy


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