PHOTOVOLTAIC SOLAR ENERGY COLLECTOR

We must emphasize that, although the words plates, panels, modules and collectors are used as synonyms, there are differences between them.

The use of solar energy is mainly done through two profoundly different procedures: one is the generation of electricity, while the other is the accumulation of heat; for the first case, modules, plates or photovoltaic panels are used, while for the use of heat, we have solar collectors that, obviously, are built with a technology very different from the previous ones. We went on to the different types of collectors.

Plates, modules or photovoltaic solar panels

The  plates, solar modules or planles , are synonymous and used to designate such photovoltaic modules called, that is, those who produce electricity. Within a photovoltaic installation, the best known component is the  plate, module or solar panel,  which uses certain semiconductor materials and captures the photons transmitted in sunlight to transform them into a continuous stream of electrons, that is, electricity.

These materials are arranged in sets of cells, interconnected in series or in parallel and protected by a glass in the upper part and by several plastic layers in the back, all reinforced by a metal frame. On the back are the relevant electrical connections.

There are three main types of modules, depending on the material that forms the cells:

• to. amorphous materials: they have a high degree of disorder in the structure of atoms. Its construction is simple and cheap.
• b. polycrystalline materials: they have more quality than the previous ones, so their effectiveness is greater. They are also more expensive.
• c. monocrystalline materials: they are the highest quality, although in recent years they have been almost reached by new polycrystalline patents, and currently their performance is only slightly higher.

Thermal collectors or solar collectors

The  solar collectors  are the type of solar panel used in solar thermal energy, ie, the heat accumulating to pass it to the water that will be used in faucets, showers and heating circuits.

The   most common solar collectors are the so-called planes. They consist of an absorbent plate, which must be dark to have the maximum rate of heat absorption and the minimum of reflection, that is, to maximize the energy of the sun’s rays and minimize losses. Welded to the plate, a coil of copper tubes is heated by the heat transmitted to it by the plate, which then heats the liquid that flows through it.

These elements are protected by a very resistant glass, to withstand the inclemency of the weather, and with low iron content to have the maximum transparency index (lower losses due to reflection and absorption).

The whole set is perfectly insulated, with polyurethane or fiberglass, to reduce losses as much as possible.

It should be mentioned that the fluid circulating inside the coil is antifreeze and not water, as it might seem, thus protecting the collector from possible frost.

Vacuum tube solar collectors

Vacuum solar collectors include an innovation: a vacuum has been made in the space between the protective glass and the absorbent surface. With this change it is possible to eliminate the losses by internal convection, since internally there is no air that can transfer them, and thus increase the working temperature and performance.

The shape of these collectors is no longer flat, but cylindrical, since it allows a better vacuum to be made inside. In addition, the vacuum tube collectors allow the integration of cylindrical-parabolic concentrators (CPC) with what is achieved to improve the performance during the seasons in which the solar rays do not affect the optimum angle.

They also allow to adapt better to those cases where they can not be placed at the optimum inclination or direction, where the flat panels would have very little performance. This property makes the CPC vacuum tube collectors perfectly integrated into the architecture.

Thermosyphonic solar collector

If you want to save to the maximum in the production of sanitary hot water, the temosifónicos equipment do not consume electrical energy, since they work without pump.

This capacity helps to reduce the energy of a home and makes the equipment autonomous: they continue to work even if the electrical system fails.

The fact of being autonomous makes its application very attractive in remote places where the electricity grid does not reach. Thus, hot water can be produced even if the electrical generating group is disconnected.

Thermosyphonic operating principle

The thermosiphonic equipment works by gravity. The sun heats the fluid that is inside, it increases in temperature, decreasing its density and flows to the top, allowing the coldest fluid to occupy its place to warm up.