• Sankey diagrams can also be used to represent more complex examples of energy transfer.

  

  The diagram above shows how the energy of the fuel in a power station is used. Only about one-third of the input energy is delivered to consumers.

Thermal energy transfer

• The three principal methods of thermal energy transfer are:
  1. conduction
  2. convection
  3. radiation
• Conduction – Particles gain energy when heated. In a solid the particles cannot change positions but they vibrate, and this transfers the energy through the solid from particle to particle. In addition metals are particularly good conductors because they have free-moving electrons. Collisions between the vibrating particles and the moving electrons cause energy to be transferred quickly.