Geothermal Energy Definition
Geothermal energy is a renewable energy that uses subsoil heat to acclimatize and obtain sanitary hot water in an ecological way. Although it is one of the least known renewable energy sources, its effects are spectacular to admire in nature.
Geothermal energy Advantages
- It is a source that reduces energy dependence on fossil fuels and other non-renewable resources.
- The waste produced is minimal and causes less environmental impact than that caused by oil and coal.
- The great economy system, both economic and energy.
- It does not generate external noise.
- Geothermal resources are practically inexhaustible on a human scale.
- It is not subject to international prices, but it can always be updated to national or local prices.
- The land area required by geothermal plants per megawatt is less than that of other types of plants. It does not require the construction of dams or the cutting of forests.
- The CO2 emissions, greenhouse effect, are lower than those that would be emitted by the same energy by combustion and can be null when the water is reinjected, circulated, closed, making the external circuit.
Disadvantages of geothermal energy
- In dry deposits, microorganisms have sometimes been produced as a result of the sudden cooling of the hot stones and their consequent cracking.
- The following disadvantages refer exclusively to geothermal energy which is not used with reinjection and which is not of low domestic enthalpy (geothermal conditioning).
- n some cases, the emission of hydrogen sulfide is detected by its rotten egg odor, but in large quantities, it is not perceived and it is lethal.
- Pollution of nearby waters with substances such as arsenic, ammonia, etc.
- Thermal contamination
- Deterioration of the landscape.
- It cannot be transported (as primary energy) unless it is done with a different heat exchanger than the water in the aquifer.
- It is only available in certain places, except for the geothermal air conditioning pump, which can be used anywhere on Earth.
Geothermal energy applications
Geothermal energy applications are based on the use of thermal energy and the generation of electricity. On a more concrete level, some of the applications of this renewable energy are the following:
- Air conditioning in summer: In a house with underfloor heating, the heating fluid can be circulated underground. This water will acquire approximately a temperature of 15ºC that will facilitate the cooling of the house.
- Winter heating: For the same reason as for air conditioning. In this case, we will use a heat pump to pass the 15ºC to the 19 or 20ºC in which we want to put the heating. This model is also applicable to greenhouses, animal farms, etc.
- Production of sanitary hot water for bathing, washing clothes, dishes, etc.
- Electricity production in power plants.
- Heat production that can be applied to industrial processes such as heating, drying, evaporation, distillation, sterilization, thawing, washing, and extraction of salt.
Geothermal energy production
The geothermal energy production system is based on the temperature difference between the subsoil and the surface. The energy is exchanged in the form of heat – thermal energy – through two closed water circuits that connect them. For winter heat, the water inside the geothermal energy sensor circuit, which is a plastic circuit, arranged in vertical holes that reach between 80 and 200 meters deep, is driven by a subsoil pump to heat, the water heats up the circuit that emits radiation, a closed circuit that provides heat to the building. In summer, the operation is analogous, but the heat moves in the opposite direction. The efficiency of geothermal energy is greater the deeper the underground circuit is, since the temperature difference is greater.
To obtain hot water, the collector circuit heats the hot water in an open circuit, which comes from the water network and can be stored in one or more tanks. Hot water can also be used to move a turbine, thus transforming geothermal energy into mechanical energy, in this case kinetic energy. Mechanical energy can be used to move machines or convert them into electrical energy: electricity.
For small renewable energies (production up to 30 kilowatts (KW) and can have horizontal and surface heat collecting dialects water pipes, that is, between one and five meters, normally between one and a half and two, for example, under a The heat pump is the size of a fridge, but it is very quiet and can be placed in the garage, for example.
Types of geothermal sources
Geothermal energy is obtained by extracting the Earth’s internal heat. There are several areas with hot springs. These hot springs can be those used in spas or other centers. These waters are heated by the temperature inside the Earth. In areas where the hot springs are very hot, surface drilling is done through natural fractures.
Hot water and/or steam, which have a certain amount of internal energy, can flow naturally, through the impulses of water and steam, but also through pumping. You have to select the method to use depending on the method that is most economically profitable. There is no single method to exploit this energy, as there are projects in some countries that have had to be rejected due to their economic impracticality.
Magma – geothermal energy:
Magma (molten rock) is an important source of geothermal energy since rocks are only found in a liquid state at extremely high temperatures. However, with the technology available today, it is not possible to take advantage of this type of renewable energy sources, it is economically unfeasible. The farm to extract hot water, usually has an even number of wells, such as for one hot water extract and the other water is reinjected into the aquifer, and when it cools. This system has several advantages:
There is little chance that the water in the tank will run out since when continuously injected the volume remains constant. There are no emissions of dissolved gases, since the water circuit is closed, which prevents possible contamination from the outside.
High temperature geothermal energy:
This type of renewable energy is found in areas where the crust layer is still active and the temperature ranges from 150 ° C to 400 ° C. In these cases, the steam reaches the surface through a turbine that generates electricity when moved by the force of the steam. To find an area from which to extract hot water, a geothermal area, you have to find a top layer consisting of:
- Coating of waterproof rocks, which allow water filtration.
- Highly permeable aquifer or reservoir, between 300m and 2km deep.
- Fractured soil, allows the circulation of fluids by convection, so that heat transfer reaches the surface.
- Magmatic heat source, at a depth between 3 and 15 km, and at a temperature between 500 ° C and 600 ° C.
- Drilling to extract hot water is nearly the same as drilling to extract oil from wells.
Average temperature of geothermal energy:
In medium temperature geothermal energy facilities, the temperature of the aquifer fluids is at significantly lower temperatures, at temperatures ranging from 70 ° C to 150 ° C, for which the conversion performance of electricity into steam is much less, in this case, you have to add a volatile component. This type of geothermal energy can be transformed into small plants, but it is in the distribution through the urban network where the maximum use is made, it is used for heating and cooling, with absorption machines. This is used for the production of electricity, it is necessary that the fluid is between 120 ° C and 180 ° C.
Low temperature geothermal energy:
It is used in large areas, in areas larger than those working at high or medium temperatures. It is found in sedimentary basins, the fluid in these basins is at a temperature between 50 ° C and 70 ° C.
Geothermal energy at very low temperature:
It is used to meet domestic, urban, and agricultural needs. The fluids that can be found are found at temperatures between 20 ° C and 50 ° C. Both low-temperature geothermal energy and very low-temperature geothermal energy are very useful for district heating systems, through closed circuits.
Geothermal power plants have the function of generating electricity from thermal energy inside the Earth. For this, they have heat exchangers with the aim of generating steam. With the pressure of the steam, a turbine is activated, obtaining mechanical energy. The mechanical energy obtained by the turbine can be easily converted into electrical energy by means of an electric generator.
Relationship in which, at a certain distance from the surface at sea level, towards the interior, increases 1ºC.
Relative to the internal energy of matter, generating heat through the decomposition of different isotopes.
They are points on the map where we find a higher temperature, for absolutely natural reasons. Could it be areas of cracks or breaks in tectonic plates, or areas with the activity that cause earthquakes, eruptions? There are four types of deposits:
- High-temperature tanks: There is a heat source, where the fluid is stored at around 100ºC. The focus is surrounded by permeable rock, which in turn is surrounded by a layer of cracked rock.
- Low-temperature deposits: The temperature ranges between 100 and 60ºC.
- Deposits at very low temperature: Above 15ºC.
- Hot rock deposits: rocks that are 5 to 8 kilometers underground.
- Mechanical Energy
- Kinetic energy
- Potential Energy
- Geothermal Energy
- Sources of energy
- Nuclear energy
- Conservation of Energy
- Solar Energy
- Radiant Energy