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…
For the conversion of fossil energy into electrical energy, the technology of a thermal power plant is often used. At the moment in which a thermal power station is fossil fuels fossilized from a source of non-renewable energy generation.
A thermal power plant (or thermoelectric plant) is a plant that generates electricity by transforming heat. Historically heat energy is converted into electricity by transferring heat to a working fluid and then transforming the energy of this fluid into mechanical energy. Finally, mechanical energy is transformed into electricity. The…
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.…
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…
A solar concentrator is a concentration system of solar energy that is used to convert solar energy into thermal energy. Its operation is based on the exploitation of the reflection of the solar rays obtained through reflective surfaces (substantially of mirrors), in order to concentrate on a receiver of contained size. Similar to a magnifying glass focusing its light on a point, the concentrators reflect sunlight by means of an arrangement of mirrors aligned towards a lens capable of capturing that energy for its use.
In general, heat is converted into mechanical energy by means of…
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…
One of the applications of solar thermal energy is the obtaining of sanitary hot water (DHW). 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 DHW is an important component to take into account, since it represents between 25 and 40% of the energy consumption of homes.
Solar thermal energy is a way to harness the heat of solar energy from to get heat. Of the different techniques to convert solar radiation into thermal energy, in this section, we explain high-temperature solar thermal energy.
We refer to high-temperature solar thermal energy to those solar systems that use solar collectors that work at temperatures above 500ºC. In this type of installations, once the solar radiation has been transformed into heat energy, the next objective is to transform this heat into electrical 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:
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,…
According to the first law of thermodynamics, every process that occurs in a given system must satisfy the principle of conservation of energy, including the flow of heat.
states, in other words, that any process whose sole purpose is to create or destroy energy, is impossible, that is, it denies the existence of a first-class perpetual motion machine.
However, the first law does not tell us anything about the…
A forced circulation for solar water heater is an installation in which the water circulates inside the circuit driven by a pump. With forced circulation system, the movement of water in the closed circuit is forced by a pump. This feature makes a big difference with respect to sanitary hot water installations with thermosyphon. In this way, it artificially moves the hot water not to the highest point of the closed circuit, but it does so from the solar collectors down to where the accumulator is located.
In many occasions it is not viable to install solar thermal equipment…
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…
Low-temperature solar thermal installations are considered those installations of solar thermal energy that provide useful heat at temperatures below 65 ° C 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.
The circulation of 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 with a circulation…
The solar thermal energy consists of the use of the energy coming from the Sun to transfer it to a medium that carries heat, generally water or air.
Among the different applications of solar thermal energy there is the possibility of generating electrical energy. The current technology allows heating water with solar radiation to produce steam and then obtain electrical energy.
Although the principle of operation is very similar there are two main applications of solar thermal energy:
- Use of solar thermal energy in homes and small installations…
Definition of temperature: The temperature is the thermodynamic magnitude that shows the thermal energy of one body in relation to another.
Although the definition of temperature is simple and concise, you can explain what the temperature is in a more extensive way: What is the temperature?
Temperature is a physical quantity of matter that quantifies the common notions of heat and cold. The objects of low temperature perceive them cold, while objects of higher temperatures we consider them warm or hot. This physiological sensation of cold and heat is generated…
In thermodynamics, a thermodynamic cycle is a circuit of thermodynamic transformations performed on one or more intended devices. The objective of these transformations is to obtain work from two sources of heat at different temperatures, or conversely, to produce through the contribution of work the passage of heat from the source of lower temperature to higher temperature.
Obtaining work from two thermal sources at different temperatures is used to produce movement, for example, in thermal engines or alternators used in the generation of electrical energy. Performance is…
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…
A solar collector of evacuated tubes is a type of solar panel that uses solar thermal energy. The finality of solar collectors is converting solar radioation into thermal energy.
This renewable solar energy system uses a type of solar panel consisting of linear collectors housed in evacuated glass tubes.
The evacuated tube solar collector 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.
The vacuum has been made between the transparent outer tube and…