Topic 8.1: Energy Degradation and Power Generation Notes Flashcards
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
The continuous conversion of thermal energy into work requires thermal energy to be transferred to the surrounding
For a continuous, cyclical conversion of thermal energy to occur, energy has to be lost to the surroundings, which consequently means the system requires a constant input of energy
2nd Law of Thermodynamics
It is impossible to take heat from a hot object and use it all to do work without losing some to the surroundings
8.1.2: Explain what is meant by degraded energy
Understand that, in any process that involves energy transformations, the energy that is transferred to the surroundings (thermal energy) is no longer available to perform useful work
Degradation of energy is the process of energy transforming into disordered, spread out energy
energy, while always being conserved, becomes less useful, it cannot be used to perform mechanical work- this is called energy degradation
8.1.3: Construct and analyze energy flow diagrams (Sankey diagrams) and identify where the energy is degraded
Sankey diagrams illustrate the flow of a system, can be used to display the flow of energy (how useful energy is produced
energy input from the left
wasted or unwanted energy forms (vertically down)
useful energy output to the right
width represents the amount of energy
What is efficiency?
useful mechanical work done/ input energy
8.1.4: Outline the principle mechanisms involved in the production of electrical power
Understand that electrical energy may be produced by rotating coils in a magnetic fields
Electricity is produced using electrical generators by rotating a coil in a magnetic field so that magnetic field lines are cut by the moving coil
According to Faraday’s law and emf (voltage) will be created in the coil which can then be delivered to consumers
Generators convert mechanical energy into electrical energy
What can electrical power be generated from?
heat source; steam generation; turbines; generator; transmission lines
