Frequent questions

Frequently Asked Questions About Solar Energy

Frequently Asked Questions About Solar Energy

In this section we intend to answer the main questions related to solar energy.

Generally, these are general topics that could be located in several sections of the web. Our intention is to expand this section in the future to publish generalist articles and curiosities of nuclear energy.

Most of the questions are focused on small solar installations, comparative with solar thermal energy and photovoltaic solar energy.

In the future we will also answer on more oriented questions in the field of physics: thermodynamics, forms of energy, mechanical energy, potential energy, etc. Likewise, we will also make comparisons with a certain renewable energy or with the energies that come from fossil fuels.

Are solar thermal and photovoltaic installations compatible


Solar thermal and photovoltaic systems are technically independent from each other. With the same solar panel, thermal energy and electrical energy can not be obtained at the same time.

However, in an installation you can combine solar thermal collectors with photovoltaic solar panels. With the thermal collectores we can obtain sanitary hot water or heating and with the photovoltaic panels we can generate electric power.

Therefore, we can say that they are perfectly compatible technologies.

How long does it take to amortize a solar installation?

There are different factors that determine the amortization period of an installation:

  • The correct calculation of the needs of the solar installation
  • System optimization
  • Proper installation and quality of materials
  • The public subsidies obtained.
  • The use of solar panels.

On average, thermal installations are amortized approximately at 4-6 years. In turn, photovoltaic installations are amortized from 7-9 years.

How long does a solar installation have?

In the case of solar thermal systems, solar installations have a life span of more than 25 years.

In the case of photovoltaic installations, the lifespan is greater than 30 years.

What is the relationship between the amount of sun received and the yield obtained?

In the case of solar thermal energy, solar collectors not only capture solar radiation during clear days. The diffuse radiation existing during cloudy days can also be exploited but at a lower yield than in favorable circumstances. However, during long periods of adverse weather it will be necessary to provide more energy through conventional support systems to maintain the optimum temperature of use.

In the case of photovoltaic installations, these generate electricity throughout the year, while receiving solar radiation. On cloudy days, photovoltaic modules also generate electricity, but at a lower yield.

It should be noted that electricity is generated from solar radiation, not from heat, so cold does not represent any problem for photovoltaic use. In fact, like most electronic components, photovoltaic panels operate more efficiently at lower temperatures, always within limits.

How can the situation of solar installations be optimized?

Solar panels operate better if they are placed in a place where they receive full sunlight. They can be placed on the roof of a house or office, on a support structure, mounted on the facade or on the ground. It is preferable to avoid places that receive shade (vegetation, snow, other buildings, constructive elements, other modules, etc.), at least during the central hours of the day, since shade will affect their performance.

Due to the change of position of the Sun during the year, the ideal inclination of the panels varies according to the latitude in which we are. Normally 45 ° is used in thermal and 30 ° in photovoltaic, but the inclination may vary depending on the application, criteria of use and architectural integration. In any case, an inclination higher than 15 ° is recommended, to allow rainwater to drain. The inclination should be increased in places where snow frequently.

In the same way, the solar system will have a higher performance if the solar panels are oriented in the south direction.

Solar systems can be perfectly integrated into most of the existing buildings, although without a doubt, the best and easiest integration is achieved if they are included in the project of a new building.

If there is a community of owners in the building, the installation can be done by the community itself (for common use or by the individual owners), or by one of the owners for their own use, with the agreement of the community.

What is the maintenance of a solar installation?

Solar installations require minimal maintenance, and preventive. Two aspects to consider are, on the one hand, to ensure that no obstacle overshadows the panels and, on the other, to keep them clean, specifically the faces exposed to the sun.

In the case of solar thermal energy, it is necessary to be careful with low temperatures. To avoid the freezing of the fluid, it is normal to add an antifreeze, or empty the water circuit when the temperature reaches a certain value. In the case of long periods of inactivity of the solar installation (summer especially), it is advisable to cover the solar captains to prevent the fluid from reaching too high a temperature.

Impact On The Invoice
What is the impact of solar energy on the electricity bill?

¿Quieres saber cómo la energía solar puede ayudarte a disminuir tus facturas de luz? Descubrelo en este artículo y ¡empieza a ahorrar!

March 29, 2019

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Solar energy and home automation systems

One way to increase energy efficiency in a home is to install home automation systems that allow controlling different aspects of a home remotely.

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Published: December 10, 2009
Last review: October 5, 2018