Zusammenfassung der Ressource
GCSE AQA Physics 1
Energy & Efficiency
- 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
- 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.
- 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
- 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
- Cost of electricity
- kWh - units of energy
- Units = Power x Time
- Cost = Units x Price