Energy Conservation and Efficiency

Conservation of Energy and Wasted Energy

  • Energy cannot be created or destroyed, just transferred to other stores

  • Energy that is not usefully transferred is wasted, often this is dissipated to the surroundings: increasing their thermal store

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Efficiency is the ratio of the increase in the useful energy store (output) to the energy in the original store (input). This can either be expressed as a number between 0 an 1, or as a percentage.

Reducing Unwanted Energy Losses

Reducing unwanted energy losses can be achieved in many ways, including:

  • by thermal insulation

  • by lubrication

Sankey Diagrams

These are a great way to visualise the energy transfers in a device and therefore its efficiency.

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