Energy and its transformations


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Learn about Energy, energy sources and the consequences of using energy

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Energy and its transformations

  1. 1. Energy and its transformations Tecnology 3rd ESO
  2. 2. Index • • • • • Definition Types of energy Electricity Power stations Energy efficiency
  3. 3. What is energy? • We define energy as the capacity of performing any activity. The Junits of energy are: J(joule), cal (4,15 J), kw·h(1000J/s*3600s=3 600 000 J) • We define power as the capacity of performing work in a unit of time: P=Energy produced or consumed / time Units for power: W (watt), kW, CV or hp (1 C.V. = 735,5 W) Index
  4. 4. Types of energy Renewable? Origin Renewable Non Renewable Wind Hydroelectric SUN Fossil fuels Coal Photovoltaic, sun thermal Seas Gas Oil Biomass EARTH SUW (RSU) Nuclear Geothermal fuels Index
  5. 5. Electricity Electricity is an extremely useful form of electricity because: 1. It is easy to produce and transform 2. It is easy to transport Electricity is produced in power stations, which can be: Thermal, hydroelectric, wind farms, solar cells…
  6. 6. Production of electricity To produce energy we use an alternator formed by • A turbine which rotates debt to other energy(wind, water vapour) • A generator, formed by a rotor connected to the turbine and an stator. Bobines are holed along the stator and magnets conductors along the rotor. The movement of the rotor induces the production of a voltage, and thus electricuty, on the stator Index
  7. 7. Thermal stations • Thermal stations generate vapour at high pressure) to push the turbine blades of the alternator. Normally fossil fuels (coal, gas-oil, gas) are burnt to generate vapour • They are pollutant, non renewable, but very effective
  8. 8. Nuclear power stations • Nuclear power station are thermal stations where the vapour is generated with the heat from nuclear reactions: Uranium, plutonium • They are pollutant, non renewable, but very effective
  9. 9. Hydroelectric station • Sun evaporates water from seas. This provoques rain and craetes rivers, whose water is stored with dams. The energy of this water is used to generate electricty • This is renewable, non pollutant but also destroys valleys and depends on the climate.
  10. 10. Wind farms • Wind farms are groups of aerogenerators, placed over mountain tops, which convert wind into electricity. The devices use a huge turbine(fan) of 60 m (diameter) • This energy is renewable, non pollutant and quite reliable, for wind is countiuous over muntains. The pollution is visual. The generators can be dangerous for certain birds
  11. 11. Sun cells • • • Sun rays release the electrons of certain metals when they hit them. This produces a flow of charges: Photovoltaic effect This energy is renewable and non pollutant, but the materials for procing sun cells are extremely pollutant and the effiency is low This energy is used to support conventional electricity supply or when it is impossible to connect to the electric grid (satellites) Index
  12. 12. Distribution of energy • Distribution of electricity • Distribution of fuels
  13. 13. Distribution of electricity Electricity is produced in power station far away from citis or industries (consumption centres) • We use a grid to transport electricity. • Two kinds of grid are used: Transport and distribution grid • To diminish the amuont of power wasted because of the resistance of the wire, (Pw=R·I2), tension is extremely high, so I is very low (I=Pd/V). • High tension is only available in the transport grid. The distribution grid, which brings electricity to houses and industries is transformed to lower values to help electrical accidents (fires, explosions)
  14. 14. Distribution of fossil fuels • Coal is produced in mines and oil and gas are found underground (oil wells) • Coal is distributed with ships, trains or lorries to the cosumption centres • Gas and oil are distributes with ships or pipes
  15. 15. Energy effiency • Energy production and consumption is harmful for the enviroment (it is pollutant, and spends a lot of resources). • We define efficiency as Efficiency=Converted energy/Consumed energy • The most efficient a device is, the better for our enviroment and for ourselves Index