Transcript Energy
Energy Ideas for Today and Tomorrow Sources of Energy Fossil fuels Coal, Oil, Gas Non-renewable Sources of Energy Renewable Solar, Water, Wind, Geothermal Renewable Sources Advantage: free, clean Disadvantage: difficult to convert large amounts to useful forms Conserving Energy Industry: use fans to circulate heat Home: improve insulation Transport: car sharing Electricity Generation thermal power station chemical energy to heat boiler heat energy to kinetic turbine generator kinetic energy to electrical Electricity Generation hydroelectric station potential energy to kinetic turbine generator kinetic energy to electrical Electricity Generation nuclear power station nuclear energy to heat reactor heat energy to kinetic turbine generator kinetic energy to electrical Electricity Generation nuclear power station Radio-active waste produced by reactor must be stored safely for hundreds of years Chain Reaction energy energy Chain Reaction A uranium nucleus is split by a neutron. Energy is released and more neutrons are released Pumped hydroelectric schemes Water pumped to upper reservoir at night. Water flows back down through turbines at peak demand energy E energy = power x time E=Pt potential energy Ep potential = mass x gravitational x height energy field strength Ep = m g h Efficiency Energy is degraded in energy transformations Efficiency = Useful energy out x 100% Total energy input Generating Electricity A voltage is induced in a conductor when it moves through a magnetic field Generating Electricity Size of induced voltage depends on magnetic field strength, turns on the coil, speed of magnet past conductor Transformers Primary coil Secondary coil core Transformers Transformers change the size of a.c. voltages Transformers Step-down transformers have more turns on the primary The voltage goes down Transformers Step-up transformers have more turns on the secondary The voltage goes up Transformers Number of turns, NPrimary and NSecondary on each coil and the voltages VPrimary and VSecondary Transformers NPrimary VPrimary NSecondary VSecondary Transformers For a 100% efficient transformer PPrimary = PSecondary IPrimary VPrimary ISecondaryVSecondary Transformers IPrimary NSecondary ISecondary NPrimary Transformers IPrimary VSecondary ISecondary VPrimary