GCSE AQA Physics 1 Energy & Efficiency

GCSE AQA Physics 1 Energy & Efficiency

1. In the home

   • Most effective insulation - biggest annual saving
     • Eventually money saved = initial cost
   • Most cost-effective - often cheapest, short payback time
   • Cavity wall insulation
     • Foam in gaps stops convection currents & radiation - insulating foam & air pockets = reduce conduction
   • Loft insulation
     • Fibreglass wool reduces conduction & radiation
   • Draught-proofing
     • Strips around doors to stop draughts - reduce convection
   • Hot water tank jacket
     • Fibreglass wool reduces conduction & radiation
   • Thick curtains
     • Reduce conduction & radiation
   • U-Values
     • Higher = heat travels faster
       • Better insulator - lower value

2. Specific heat capacity

   • How much energy something can store
     • Amount of energy needed to raise temp. of 1kg by 1*C
   • Heaters have high SHC
     • Water ideal for central heating - high SHC, liquid
       • Electric storage heaters - store heat using concrete/bricks
     • Some filled with oil - lower SHC, not as good but higher boiling point - can safely reach higher temp.

3. Energy transfer

   • 9 types of energy: electrical, light, sound, kinetic, nuclear, thermal, gravitational potential, elastic potential & chemical
   • Energy can be TRANSFERRED from one form to another - but it can never be CREATED or DESTROYED
     • Energy is only useful when it can be converted

4. Efficiency of machines

   • Useful energy / Total energy
   • No device is 100% efficient & wasted energy is usually spread out as heat
     • Less concentrated but total amount is the same - can't easily be used
   • Heat exchangers
     • Pump cool fluid through heat - temp. rises, can convert into useful form

5. Cost of electricity

   • kWh - units of energy
     • Units = Power x Time
       • Cost = Units x Price

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