Panels photovoltaic solar energy

Installation of thermal solar energy

Solar power plant
Thermoelectric

Temperature

Kelvin degree

Kelvin degree

The Kelvin is the temperature unit of the International System. The Kelvin is one of the seven basic units of temperature. Its symbol in the international system of units is K. The Kelvin scale is a thermodynamic (absolute) temperature scale where the absolute zero, the theoretical absence of energy, is zero (0 K). This unit is named after the British physicist, mathematician and engineer William Thomson (1824 - 1907), who was later named Lord Kelvin. Lord Kelvin wrote about the need for a "thermodynamic temperature scale".

To express the temperature difference or the interval, the use…

Temperature

Temperature

Temperature is a physical quantity of matter that expresses quantitatively the common notions of heat and cold. The objects of low temperature are cold, while objects of higher temperatures are considered warm or hot. The temperature is measured quantitatively with thermometers. The thermometers can be calibrated with respect to different temperature scales.

Scales to measure temperature

The three most common scales to measure the temperature are:

  • The Celsius scale (degrees centigrade)
  • The Kelvin scale
  • The Fahrenheit scale

Almost everyone…

Heat

Heat

In physics, in particular in thermodynamics, heat is defined as the contribution of transformed energy as a result of a chemical or nuclear reaction and transferred between two systems or between two parts of the same system. This energy is not attributable to a job or a conversion between two different types of energy. Heat is, therefore, a form of transferred energy and not a form of energy contained as internal energy.

As the energy is exchanged, the heat is measured in the International System in joules. In practice, however, it is often still used as the unit of measurement of calories,…

Geothermal energy

Geothermal energy

Geothermal energy is a type of renewable energy on a human scale that is obtained from the heat of the interior of the Earth. Equestrian thermal energy can be obtained without the combustion of any material, it is therefore a form of clean energy without carbon dioxide emissions.

The temperature in the inner layers of the Earth remains constant during the different seasons of the year. Generally the inner layers are hotter than the surface in winter and cooler in summer. This is because the surface layers are heated and cooled more easily according to the laws of thermodynamics.

Isothermal process

Isothermal process

In thermodynamics, an isothermal process is a thermodynamic transformation at constant temperature, that is, a variation of the state of a physical system during which the temperature of the system does not change with time. Devices called thermostats can maintain a constant temperature value.

The isothermal transformation of a perfect gas is described by Boyle's law which, in a pressure-volume diagram (or Clapeyron's plane), is represented by a branch of the equilateral hyperbola.

Isotherm of a perfect gas Calculation of heat and work exchanged

For isothermal gas…

Flat solar collector

Flat solar collector

The flat plate thermal solar collector has a good cost / effectiveness ratio in moderate climates and adapts correctly to a large number of applications (hot water heating, pool heating, heating support, preheating industrial fluids, etc.).

We can distinguish two basic types of flat plate collectors, depending on the configuration of the absorber: the "grid type" parallel, in the vertical and horizontal versions and the "serpentine type" series. Basically, the difference between the two is:

  • The parallel configuration favors that the temperature of the collector can be stratified…

Grade Fahrenheit

Grade Fahrenheit

The Fahrenheit degree (° F) is a temperature unit proposed by Gabriel Fahrenheit in 1724.

On the Fahrenheit scale, the melting point of water is 32 degrees of temperature, and the boiling point is 212 degrees. A difference of 1.8 degrees Fahrenheit equals that of 1 degree Celsius. Fahrenheit established the zero temperature (0 ° F), the freezing point of a 50% mixture of salt (ammonium chloride) and ice, and as 96 ° F, he took the temperature of the blood (he used that of the horses ). The figure 96 may seem an odd measure, but in principle the scale contained only twelve…

Uses of geothermal energy

Uses of geothermal energy

Geothermal energy is a long-term source of energy worldwide. With the geothermal energy stored in the top three kilometers of the Earth's crust, theoretically, the current energy demand could be covered for more than 100,000 years. However, only a small part of this energy is technically usable and the effects on the earth's crust during extensive heat dissipation are not yet clear.

When geothermal energy is used, a distinction is made between direct use, that is, the use of heat in itself, and indirect use, the use for conversion into electricity in a geothermal power plant. With the…

Thermal solar collectors

Thermal solar collectors

A solar thermal collector is a component of a solar thermal installation. A solar collector is a type of solar panel responsible for capturing solar energy and transforming it into heat. It is also called the solar thermal collector.

The solar collector is the basic element of this renewable energy source.

From solar collectors there are many types. The solar collector used will depend on the use that is going to be given. For example, if we want to heat a pool to a temperature of 25-28ºC, in the spring, we need a simple sensor, since the ambient temperature will easily be…

Low temperature thermal solar energy

Low temperature thermal solar energy

Low thermal solar installations are considered those installations that provide useful heat at temperatures below 65ºC through solar energy.

A low-temperature solar thermal installation consists of solar collectors, two water circuits (primary and secondary), heat exchanger, accumulator, expansion vessel and pipes.

Circulation of the water inside the circuits can be obtained by thermosiphon, taking advantage of the density difference of the water at different temperatures or by means of a circulation pump, although in this case an external contribution of electrical energy…

Solar thermal energy

Solar thermal energy

The solar thermal energy consists of the use of energy from the Sun to transfer it to a medium that carries heat, usually water or air.

Among the different applications of solar thermal energy there is the possibility of generating electric power. The current technology allows to heat water with solar radiation to produce steam and subsequently obtain electrical energy.

Although the principle of operation is very similar there are two main applications of solar thermal energy:

  • Thermal single energy for use in homes and small installations
  • Large thermal solar…

Thermodynamics

Thermodynamics

Thermodynamics is the branch of classical physics that studies and describes the thermodynamic transformations induced by heat and work in a thermodynamic system, as a result of processes that involve changes in the temperature and energy state variables.

Classical thermodynamics is based on the concept of macroscopic system, that is, a portion of physical mass or conceptually separated from the external environment, which is often assumed for convenience that is not disturbed by the exchange of energy with the system. The state of a macroscopic system that is in equilibrium conditions…

Domestic hot water (DHW)

Domestic hot water (DHW)

One of the applications of solar thermal energy is the obtaining of sanitary hot water (ACS). Solar collectors capture the energy of solar radiation to increase the temperature of a fluid.

Domestic hot water (DHW) is water intended for human consumption (potable) that has been heated. It is used for sanitary uses (bathrooms, showers, etc.) and for other cleaning uses (washing dishes, washing machine, dishwasher, floor scrubbing). In terms of energy, the ACS is an important component to take into account, since it represents between 25 and 40% of the energy consumption of homes.

As…

Thermodynamic processes

Thermodynamic processes

In physics, the thermodynamic process is called the evolution of certain quantities (or properties) properly thermodynamic relative to a particular thermodynamic system. From the point of view of thermodynamics, these transformations must proceed from a state of initial equilibrium to a final one; that is, that the magnitudes that undergo a variation when passing from one state to another must be perfectly defined in said initial and final states.

In this way the thermodynamic processes can be interpreted as the result of the interaction of one system with another after being eliminated…

Entropy - Thermodynamics

Entropy - Thermodynamics

What is entropy? Entropy (S) is a thermodynamic quantity originally defined as a criterion for predicting the evolution of thermodynamic systems.

Entropy is a function of extensive character state. The value of entropy, in an isolated system, grows in the course of a process that occurs naturally. Entropy describes how a thermodynamic system is irreversible.

The meaning of entropy is evolution or transformation. The word entropy comes from the Greek.

Entropy in the world of physics

In physics, entropy is the thermodynamic magnitude that allows us to calculate the…

Third law of thermodynamics

Third law of thermodynamics

The third law of thermodynamics, sometimes called Nernst's Theorem or Nernst's Postulate, relates the entropy and the temperature of a physical system.

The third law of thermodynamics states that absolute zero can not be achieved in a finite number of stages. The third law of thermodynamics can also be defined as that when reaching absolute zero, 0 degrees Kelvin, any process of a physical system stops and when reaching absolute zero the entropy reaches a minimum and constant value.

This principle states that the entropy of a system at the absolute zero temperature is a well-defined…

Zero law of thermodynamics

Zero law of thermodynamics

The zero law of thermodynamics speaks of what we experience every day: two systems that are in thermal equilibrium with a third are in equilibrium with each other. It is said that two bodies are in thermal equilibrium when, on contacting each other, their state variables do not change. Around this simple idea the zero law is established.

Every law of physics has its relevance, as well as the zero law of thermodynamics, which curiously was the last law to be introduced in literature. After the realization that heat is a form of energy that could be transformed into another, thermology…

Power accumulators

In the autonomous electricity supply facilities, it is necessary to store the energy captured during the hours of solar radiation in order to cover supply during the hours when there is no (daily cycle and seasonal cycle).

Features accumulators:

  • Electric batteries have a very important and fundamental to the proper functioning and duration of a solar photovoltaic installation function.
  • They must have sufficient capacity to ensure supply of electricity during periods of clouds (autonomy of installation).
  • It is reversible electrochemical systems…

Thermal temperature

Thermal temperature

Thermal temperature is the absolute measure of temperature and is one of the main parameters of thermodynamics. Its unit of measure in the international system of measures is the Kelvin.

This is an "absolute" scale because it is the measure of the fundamental property of temperature: its zero value, or absolute zero, is the lowest possible temperature. There is nothing that can have a temperature below absolute zero. The absolute zero of the thermodynamic temperature, transformed in the Celsius scale would be equal to 273,5ºC. This characteristic is defined by the third law of thermodynamics…

High-temperature solar thermal energy

We refer to hight-temperature solar thermal to those collectors who work at temperatures above 500 ° C. They are used for power generation.

The technologies used in hight-temperature solar thermal energy are:

  • Parabolic trough solar collectors
  • Central tower
  • Parabolic dishes or parabolic reflector
  • Linear Fresnel concentrators
Parabolic trough solar collectors

Thermosyphon solar systems

These equipments have a natural circulation based on convection currents formed in the fluid at different temperatures.

If we heat a water tank at the bottom when the bottom water warms, it becomes less dense and rises to the surface where it cools. Then returns to the bottom of the container and thus a natural circulation flow is generated.

This is the operating principle of a thermosiphon team, which will be essential that:

  • The solar collector (heat sources) is always located below the level of the accumulator.
  • The primary circuit is as short as possible…

Medium temperature solar thermal energy

Medium temperature solar thermal energy

Low-temperature solar thermal energy is used in applications that require temperatures between 100ºC and 250ºC. From 80ºC the flat collectors practically no longer have any performance and it is necessary to resort to other capture systems.

Low-temperature thermal energy systems are used mainly for applications that demand thermal energy, that is, heat between 125º C and 400º C. To reach higher temperatures it is necessary to concentrate the solar radiation.

For this type of solar thermal energy, two types of solar collectors are used:

  • Solar…

Geothermal heat pump

Geothermal heat pump

The geothermal heat pump is an air conditioning system for buildings that exploits the heat exchange with the superficial subsoil, by means of a heat pump. Since the heat in the subsoil comes largely from the interior of the Earth, geothermal energy of low enthalpy is classified as a source of renewable energy, although the heat pump itself consumes electricity, generally produced from other sources of energy (for example, fossil fuels).

The heat pump allows the exchange of heat between a "source" at a lower temperature than the "well", or the point where the heat is introduced. In a…

Isobaric process

Isobaric process

In thermodynamics, an isobaric process is a change in the state of a certain amount of matter in which the pressure does not change, but one or more of its state variables. An example of this is air in a cylinder with a freely movable piston to which heat is supplied. Due to the increase in temperature, the volume will increase, but the pressure will remain constant.

The isobaric process is governed by Charles's law. The Frenchman Jacques A. Charles (1742-1822) was the first to make measurements about gases that expand when their temperature increases.

Examples of isobaric processes

Celsius degree / celsius degree

Celsius degree / celsius degree

The degree Celsius or degree Celsius (in symbol in ° C), is the unit of a temperature measurement scale, named after the Swedish astronomer Anders Celsius (1701 - 1744), who proposed it for the first time in 1742.

The Celsius scale fixes the melting point of ice in a mixture of water saturated with air at 0 ° C and the boiling point at 99.974 ° C under standard pressure conditions (1 bar, a little less than one atmosphere, pressure in the one that the water boils at 100 degrees centigrade).

Originally conceived by the Celsius scale had the boiling point of water at…

Adiabatic process

Adiabatic process

An adiabatic process is a thermodynamic process in which the system does not exchange heat with its surroundings. An adiabatic process may also be isentropic, which means that the process may be reversible.

The adiabatic process provides a rigorous conceptual basis for the theory used to expose the first law of thermodynamics and, as such, is a key concept in thermodynamics.

The term adiabatic refers to elements that impede the transfer of heat with the environment. An isolated wall is quite close to an adiabatic limit. Hence the adiabatic wall term appears.

A process that…

First Law of Thermodynamics

First Law of Thermodynamics

The first law of thermodynamics was announced by Julius Robert von Mayer in 1841. It is the principle of conservation of energy.

Definition of the first law of thermodynamics: The total energy of an isolated system is neither created nor destroyed, it remains constant. Energy only transforms from one type to another. When one energy class disappears, an equivalent quantity of another class must be produced.

A body can have a certain speed with what has kinetic energy. If it loses speed, this kinetic energy that it loses becomes another type of energy, whether it is potential energy…

Geothermal. What is it?

Geothermal. What is it?

Geothermal energy is the discipline of Earth Sciences that studies the set of natural phenomena involved in the production and transfer of heat or thermal energy from within the Earth.

In a broad sense, the geothermal concept can also be extended to the study of other planets. Its principles are exploited at a technological level in the production of electricity and cogeneration through geothermal power plants from the associated geothermal energy.

The origin of earth's heat from a geothermal

The heat of the Earth's core was originally generated during the accretion of…

Sun

Sun

The Sun is a star around which the Earth turns.

It has an approximate diameter of 1,400,000 km and a mass of 1.99 × 1033 g.

The Sun revolves around itself. However, since it is constituted by a large mass of gases, the different regions do not rotate in solidarity, but they do so at different speeds, which depend on latitude.

The Sun, and with it the entire solar system, moves towards a point in the firmament located in the constellation of Hercules at a speed of about 19 km / s. This is because the Sun has a movement of translation around the galactic center, like…

Solar batteries

Solar batteries

The batteries in a photovoltaic solar energy system is to accumulate the energy produced by the photovoltaic panels during the hours of Sun to be able to use it at night or on cloudy days.

The use of batteries also allows to provide a higher current intensity than a functioning photovoltaic panel can offer. This would be the case if several electrical appliances were used at the same time.

A battery consists of small 2V accumulators integrated in the same element; Has direct current at 6, 12, 24 or 48V. The accumulator is the cell that stores energy through an electrochemical…

Advantages and disadvantages of geothermal energy

Advantages and disadvantages of geothermal energy

Geothermal energy is a renewable energy obtained from the heat stored inside the Earth. Thanks to the laws of thermodynamics, thermal energy is transferred from the interior of the Earth to a fluid. In this way, energy is transported in the form of internal energy.

Geothermal energy is basicaly based simply on taking advantage of the fact that the subsoil temperature is warmer than on the surface, in winter, and instead cooler, in summer. This is a consequence of the fact that the surface layers of the Earth are heated and cooled much more easily than the interior, which is maintained…

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,…

Solar heating systems with forced circulation

In many cases it is not viable to install solar power equipment for the production of hot water thermosyphon, since often the location of the solar collectors is above the tank (for example, sensors on the roof and inside the accumulator & rsquo; housing, golf sensors, etc.)

.

In this type of installation, the water flowing between the collector and the accumulator can not do it by natural convection since warmer water (sensors) and is at its highest point and there is no natural force that makes displace the cold water that is already at the lowest point and is the heaviest.

Renewable energy

Renewable energy

Renewable energy is that energy that comes from practically inexhaustible natural sources. They are considered inexhaustible either because of the large amount of energy they contain or because they can be regenerated naturally.

Among the main advantages of renewable energies we highlight the following:

Renewable energies are respectful with the environment and do not pollute.In this sense, they are safer and pose fewer health risks than other sources of non-renewable energy.

In most cases they are simple to dismantle and it is not necessary to guard their waste, as it…

Vacuum tube solar collector

Vacuum tube solar collector

A solar collector of vacuum tubes is a type of solar panel that takes advantage of solar thermal energy. This type of solar panel is formed by linear collectors housed in vacuum glass tubes.

The solar collector of vacuum tubes consists of a set of cylindrical tubes. The tubes are formed by a selective absorber, located on a reflector settlement and surrounded by a transparent glass cylinder.

Between the transparent outer tube and the inner absorber, the vacuum has been made. With this, conduction and convection losses from the absorbent surface are avoided and this fact allows…

Internal energy - Thermodynamics

Internal energy - Thermodynamics

In thermodynamics, the internal energy is the total energy contained in a thermodynamic system.

The internal energy is the energy that is needed to create the system. According to this definition, the energy to displace the environment of the system, any energy related to external force fields (potential energy, gravitational energy, etc.) or any energy associated with the movement (for example, kinetic energy) is excluded from the internal energy. .

The internal energy of a system can be modified by exercising a work on it or by heating it (providing thermal energy). If we look…

Stirling engine

Stirling engine

The Stirling engine was invented in 1816 by Robert Stirling, a Scottish priest. The goal was to get a less dangerous engine than the steam engine.

The operation of the Stirling engine is based on the expansion and contraction of a gas that can be helium, hydrogen, nitrogen or air. This gas is forced to cycle cyclically from a cold source where it contracts to a hot source where it expands. It is considered as a thermal engine (thermodynamic engine) due to the presence of a temperature gradient between the two thermal sources.

Originally, the Stirling engine was conceived as an…

Origin of Earth's heat

Origin of Earth's heat

At the end of the 17th century, the Earth was conceived as a molten mass with a solid crust as a result of its cooling. It was not until the 19th century that the first calculations of the age of the Earth based on its thermal evolution were drawn up, and the term geothermal was first defined as the scientific discipline that studies earth's heat, origin of this heat, distribution and use.

Precisely, the use of this thermal energy is what has led to the development of geothermal energy. Geothermal energy allows us to take advantage of the heat energy inside the Earth in different applications,…

Geothermal energy to generate electricity

Geothermal energy to generate electricity

Geothermal energy is that energy that can be obtained by man through the use of heat from the interior of the Earth. This type of energy has many applications. One of these applications is the generation of electric power.

The generation of electricity from geothermal energy is a good complement for hydroelectric plants, which also has the advantage that it is constant throughout the year.

Geothermal plant

Geothermal power plants are the plants responsible for converting geothermal energy into electricity. A geothermal plant is a facility where electricity is generated…

Photosynthesis

Photosynthesis

Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially, using the energy of solar radiation.

Photosynthesis occurs in plants, algae, and some groups of bacteria, but not in archaea. Photosynthetic organisms are called "photoautotrophs," but not all organisms that use light as an energy source effect photosynthesis, since "photoheterotrophs" use organic compounds, not carbon dioxide, as a carbon source. In plants, algae and cyanobacteria, photosynthesis uses carbon dioxide and water, releasing oxygen as a waste product. photosynthesis is crucial…

Adiabatic wall

Adiabatic wall

In thermodynamics an adiabatic wall is a wall that does not allow the transfer of heat from one side to another. An adiabatic wall does not let out or enter any heat.

Adiabatic walls are theoretical concepts because if in case tehey would exist they would be a perfect thermal insulation. At present, any thermal insulation, however good it may be, always allows some transfer of heat energy.

Adiabatic process

An adiabatic process is a process in which the system does not exchange heat with its surroundings. An isentropic process is an adiabatic process that is also reversible.

Greenhouse effect

Greenhouse effect

The greenhouse effect is the process by which the atmosphere of a planet passes solar radiation from the Sun, but instead prevents or hinders the thermal energy output of the planet.

It is called greenhouse effect due to the similarity with the operation of the greenhouses that are able to retain the heat inside. The operation is not exactly the same, but it is very similar. The difference is that the greenhouse uses the glass and not the gases in the atmosphere to retain heat. That is why this natural phenomenon has been called the greenhouse effect.

When we talk about the greenhouse…

Thermal energy

Thermal energy

Thermal energy is the energy released in the form of heat. It can also be called heat energy. In a more technical way we can define thermal energy as part of the internal energy of a thermodynamic system in equilibrium that is proportional to its absolute temperature and is increased or decreased by energy transfer.

The thermal energy can be transformed using a thermal engine (a thermoelectric power plant uses thermal energy to generate electricity); or in mechanical work (for example, a car, airplane or ship engine).

The obtaining of thermal energy can imply an environmental…

Rated voltage

Rated voltage

In electricity, the rated voltage of an electrical device is the voltage that must not be exceeded in normal operation. The nominal adjective is because that tension usually serves to characterize the device, to name it. The nominal value indicates the theoretical or ideal value of anything that can be quantified, as opposed to the real value, which is what is obtained in a given measurement.

Another definition of rated voltage: The rated voltage is the specific potential difference for which a device or installation is designed.

As it is a nominal value it implies that the voltage…

Solar accumulator

Solar accumulator

A solar accumulator is a reservoir that separates the energy supply from the energy capture. That is, because we will not always need energy at the moment of solar radiation, the compiler is entrusted to store this energy to supply it when needed.

For this, the accumulator stores thermal energy from the solar collectors.

When the system needs, for example, domestic hot water the accumulator supplies this hot water and replaces it with cold water that comes from the network. The cold water will pass through the circuit of solar collectors exposed to solar radiation and increase…

Thermodynamic system

Thermodynamic system

A thermodynamic system is a portion of the material space, separated from the rest of the thermodynamic universe (that is, from the external environment) by means of a real or imaginary control surface (or edge), rigid or deformable.

A thermodynamic system can be the seat of internal transformations and exchanges of matter and / or energy with the external environment (that is, everything external to the system that interacts with it).

Classification of thermodynamic systems

Within thermodynamics there are three main types of thermodynamic systems: open, closed and isolated.…

Solar thermal power plant

Solar thermal power plant

A solar thermal power plant or thermosolar power plant is an industrial facility in which solar radiation is used to generate electricity. Solar radiation is used to heat a fluid. Using fluid, taking advantage of the laws of thermodynamics, the necessary power is produced to move an alternator to generate electrical energy as in a classic thermoelectric power station.

Operation of a solar thermal power station

The operation of a solar thermal power plant is based on obtaining heat from solar radiation and transferring it to a heat carrier medium. This heat carrier is usually…

History of solar energy

History of solar energy

Within the history of solar energy, in one form or another, solar energy has always been present in the life of the planet being this imprescidible for the development of life. However, the way in which human civilization has exploited it invented new strategies and tools has undergone a long evolution.

The Sun is indispensable for the existence of life on the planet: it is responsible for the water cycle, photosynthesis, etc. Already the first civilizations realized this and, as civilizations have evolved, they have also evolved techniques to harness their energy. At the beginning they…

Components of a solar thermal installation

Components of a solar thermal installation

The function of a solar thermal installation is to take advantage of solar energy to generate heat. The solar panels of these facilities capture the heat of the solar radiation that falls on them to heat a fluid. The different ways to take advantage of this hot fluid allows us to use this type of renewable energy in multiple applications.

A solar thermal installation consists of:

  • Solar collectors
  • Primary and secondary circuits
  • Heat exchanger
  • Accumulator, pumps
  • Glass of expansion
  • Pipelines
  • Main control panel.

Laws of thermodynamics

Laws of thermodynamics

Thermodynamics is mainly based on a set of four laws that are universally valid when applied to systems that fall within the constraints implicit in each.

The first principle that was established was the second law of thermodynamics, as formulated by Sadi Carnot in 1824. The 1860 already established two "principles" of thermodynamics with the works of Rudolf Clausius and William Thomson, Lord Kelvin. Over time, these principles have become "laws." In 1873, for example, Willard Gibbs claimed that there were two absolute laws of thermodynamics in his graphical methods in fluid thermodynamics.…