8.1 Energy degradation and power generation

8.1 Energy degradation and power generation
by Diego EMB

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Topic 8: Energy, power and climate change
8.1 Energy degradation and power generation


 * 8.1.1 State that Thermal Energy may be completely converted to work in a single process, but that continuous conversion of this energy into work requires a cyclical process and the transfer of some energy from the system.


 * Thermal energy may be completely converted to work in a single process, but that continous conversion of this energy into work requires a cyclical process and the transfer of some energy from the system.


 * 8.1.2 Explain what is meant by degraded energy.


 * degraded energy - in any process that involves energy transformations, the energy that is transfered to the surroundings (thermal energy) is no longer available to perform usefull work.


 * 8.1.3 Construct and analyze energy flow diagrams (Sankey diagrams) and identify where the energy is degraded.


 * Sankey diagrams are a specific type of flow diagram, in which the width of the arrows is shown proportionally to the flow quantity. They are typically used to visualize energy or material transfers between processes.Commonly used to visualize the energy accounts or material flow accounts on a regional or national level. Sankey diagrams put a visual emphasis on the major transfers or flows within a system. They are helpful in locating dominant contributions to an overall flow and as such are popular during times of resource scarcity.


 * 8.1.4 Outline the principal mechanisms involved in the production of electrical power.


 * Electric power is defined as the rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt.
 * When electric current flows in a circuit, it can transfer energy to do mechanical or thermodynamic work. Devices convert electrical energy into many useful forms, such as heat (electric heaters), light (light bulbs), motion (electric motors), sound (loudspeaker) or chemical changes. Electricity can be produced mechanically by generation, or chemically, or by direct conversion from light in photovoltaic cells, also it can be stored chemically in batteries.