Energías Alternativas PDF

## Energías Alternativas ### Definición Energías Alternativas (pàg. 77) Las energías renovables, antes consideradas como energías del futuro, now are a reality of the present and help to solve problems of traditional energies. These energies are constantly regenerated, unlike fossil fuels, which...

## Energías Alternativas ### Definición Energías Alternativas (pàg. 77) Las energías renovables, antes consideradas como energías del futuro, now are a reality of the present and help to solve problems of traditional energies. These energies are constantly regenerated, unlike fossil fuels, which are limited resources. Most come from solar energy, but despite its great potential, its use is still limited due to the high economic cost and the need to invest in technology. ### Beneficios de las Energías Renovables Renewable energies are inexhaustible and barely pollute the environment. They decrease CO2 emissions, take advantage of local resources and reduce dependence on imports. In addition, they promote the creation of jobs in technological industries, protect nature and benefit isolated rural areas. They also boost scientific research and contribute to a better territorial balance. ### Centrales Solares, punto 2 (página 79) Solar power plants produce electricity using solar energy. They can be photovoltaic, which convert light into electricity, or thermal, which generate steam to power turbines. They are sustainable, reduce emissions, but require investment and large spaces. #### El Sol como fuente de energía: - Produces light and heat, being the main source of energy on Earth. - Generates energy through nuclear fusion, transforming hydrogen into helium. - Every second, 4 million tons of mass are converted into energy. ### Ventajas de la energía solar: - Clean, free and inexhaustible (estimated lifespan of the Sun: 5,000 million years). - Can provide temperatures up to 4,000 °C for industrial processes. - It is at the base of most energy sources, both renewable and non-renewable. ### Limitaciones de la energía solar: - It is dispersed and variable depending on the season, time of day and atmospheric conditions. - Must be transformed immediately, as there are no efficient storage systems. - Low energy density (1 kW/m² maximum). - High initial cost due to the technology of capture. ### Formas de conversión de la energía solar: - Photosynthesis → Biomass → Chemical energy. - Photochemical conversion → Chemical derivatives. - Photovoltaic conversion → Electrical energy. - Thermo-chemical conversion → Thermal energy. - Thermo-mechanical conversion → Mechanical energy. ### Los 2 sistemas de hornos solares por aprovechamiento de la energía solar (pág. 80) - Parabolic solar ovens: Use curved mirrors to concentrate the sun's rays at one point, generating high temperatures. - Flat solar ovens: Use flat surfaces with glass to capture and maintain solar heat in a simpler way. ### Factors that influence the use: - Depends on the amount of solar radiation received. - Spain has an advantage due to its climate and high number of sunshine hours per year. ### Types of use: - Thermal way → Converts solar radiation into thermal energy. - Photovoltaic conversion → Directly transforms radiation into electrical energy. ### Aprovechamiento térmico: - Advantage: It has an efficiency of up to 65% in the transformation of radiant energy into thermal energy. - Types of systems: - Active: Collectors with or without concentration of radiation, solar thermal power plants. - Passive: Architectural design adapted to the climate to capture the radiation in the best way. ### Sistemas activos según la temperatura: - Low temperature → Flat collectors (greenhouse effect). Applications: - Domestic hot water. - Heating and air conditioning. - Medium and high temperature → Solar thermal power plants to obtain electricity. ### Hornos solares (application of high temperature): - Used for research on high-technology materials. - They work with parabolic mirror surfaces that concentrate the radiation at one point. - The largest solar oven in the world is in Odelló (Font-Romeu, Alta Cerdaña). ### Partes of the photovoltaic cell (point 2.3, page 84) Photovoltaic conversion allows direct transformation of solar energy into electricity through the photovoltaic effect, which occurs when a semiconductor material, such as silicon, generates electric current upon receiving luminous radiation. ### Uses and applications: - Generation of clean and renewable electricity. - Powering satellites and space technology, as solar radiation is constant and interference-free in space. - Provision of energy in isolated areas where the electricity grid does not reach. - Solar panels in homes and buildings for self-consumption. - Charging batteries and electronic devices using small solar cells. ### Importance: - It's a sustainable and environmentally friendly energy source. - Reduces dependence on fossil fuels. - It is a technology in constant development, used since the 1960s in the aerospace industry. ### Architecture Bioclimática, los ejercicios (pàg. 87) - Passive systems → Capture, store and distribute thermal energy without mechanical elements. - Basis of bioclimatic architecture, which optimizes the use of solar energy and natural ventilation to improve comfort in buildings. - Key factors in the design: - Orientation, shape and location of the building. - Materials with thermal inertia to store heat. - Distribution of openings and level of wall insulation. - Main advantage: High durability, equivalent to the useful life of the building. ### Elements of bioclimatic architecture - Glass windows → Capture solar radiation and retain heat (greenhouse effect). - Thermal mass → Stores heat in walls and ceilings. - Protective elements → Blinds, awnings, roofs and insulation. - Reflectors → Increase radiation in winter and reduce it in summer. ### Centrales eólicas (pàg. 90) ### Key points about wind power plants - Definition → They're clusters of wind turbines that transform wind energy into electricity. They can be located on land or at sea. - Origin of wind → Due to uneven heating of the Earth by the Sun, Earth rotation and atmospheric conditions. - Advantages → Clean, renewable energy with great potential. ### Types of wind turbines - Aeromotors → - Use mechanical energy directly (pumping water). - Slow machines with many blades (12-24). - Work with gentle winds (from 2 m/s). - Low power: 0.5 kW - 20 kW. - Wind turbines → - Transform mechanical energy into electricity. - Fast machines with few blades (2-3) and greater efficiency. - Work with stronger winds (from 4 m/s). - Variable power: 25 kW - 6,000 kW (current ones exceed 1,500 kW). ### Parts of a wind turbine 1. Rotor or turbine → Transforms wind energy into mechanical energy. 2. Orientation system → Aligns the rotor with the wind direction. 3. Regulation system → Controls speed and power; brakes when there are very strong winds. 4. Energy converter → Transforms mechanical energy into electrical energy. 5. Base → Structure that protects internal mechanisms. 6. Tower → Raises the rotor to improve capture and absorb vibrations.