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Energy cant be created or destroyed, it just turns into another form
Energy transfer diagrams show input, useful and wasted energy
Wasted energy is usually heat & sound. This energy goes into the surroundings
Chemical kinetic (useful)sound (wasted)heat (wasted)
An appliance that wastes les energy is called
energy efficient
Efficiency = useful energy / total energy
Energy efficient appliances can save you money
Energy is measured in Joules (J)
Sankey diagrams
are a way to show energy efficiency
The thicker the arrow , the more energy input/
output
100 Jelectrical
energy(input)
20 Jelectrical
energy(input)
10 Jlightenergy(output)10 J
heat energy(wasted)
90 Jheat energy(wasted)
10 Jlightenergy(output)
Energy efficient light bulb
Filament light bulb
How long it takes to recover the costs of an
appliance is called pay back time
If loft insulation costs £200 to install and saves you £50 a year in heating bills… the pay back
time is 4 years Ways to make a home
energy efficient
Energy saving light bulbs
Cavity wall insulation
Loft insulation
Draft excluders
Double glazing
The cavity wall insulation in a house costs £6000 to install. It has a payback time of 15 years. How much money does the insulation
save each year in fuel costs?
The double-glazing for a house costs £3,000 but saves £150 per year in fuel costs. What is its
payback time?
Electrical energy is measured in kW/h
Electrical energy = power (kW) x time (h)
The longer you use an appliance for the more
electrical energy it will transfer
Electricity costs money
The electricity company charges you for every
unit you use
1 unit = 1 kW/h
Example:How much would 10 units
of electricity cost at a price of 9p per unit?
cost =
number of units x cost
per unit
Joules
Pay back time
Electrical energy transfer
Unit of electricity
Wasted energy
Energy efficiency
Input energy
Useful energy
The unit is kW/h.The amount of energy in joules that is
transferred into the right type of energy
Number of joules that enters the device
Is equal to 1kW/hElectrical companies charge consumers by
units
The time it takes to recover the cost of an energy efficient appliance before you can start
saving money
The amount of energy in joules that is transferred into the wrong type of energy
The amount of electrical energy used and can be measured by power (kW) x time (h)
How well a device transforms input energy into useful energy
The unit for energy
Energy transfer and efficiency
Joules
Pay back time
Electrical energy transfer
Unit of electricity
Wasted energy
Energy efficiency
Input energy
Useful energy
The amount of energy in joules that is transferred into the right type of energy
Number of joules that enters the device
Is equal to 1kW/hElectrical companies charge consumers by
units
The time it takes to recover the cost of an energy efficient appliance before you can start
saving money
The amount of energy in joules that is transferred into the wrong type of energy
Is measured in kW/hThe amount of electrical energy used and can
be measured by power (kW) x time (h)
How well a device transforms input energy into useful energy
The unit for energy
Energy transfer and efficiency
Energy efficient devices usually coast money to install…
The longer an appliance is used for…
The cost of using an appliance will increase when…
If solar panels cosy £2000 pounds to install and it saves £250 pounds in electricity bills
per year…
An energy efficient device…
A Sankey diagram…
Energy cannot be…
Wasted energy is usually…
You use the appliance for longer and when the appliance uses a greater amount of power
It will take 8 years to pay back the cost
Created or destroyed
Is a graph showing input, useful and wasted joules
Heat or sound and goes into the surroundings
The more electrical energy it will transfer
Turns more of it’s input energy into useful energy and wastes less energy
But will save money in the long term. The time is takes to recover the cost of the device is
called pay back time
Energy transfer and efficiency
Energy efficient devices usually cost money to install…
The longer an appliance is used for…
The cost of using an appliance will increase when…
If solar panels cosy £2000 pounds to install and it saves £250 pounds in electricity bills
per year…
An energy efficient device…
A Sankey diagram…
Energy cannot be…
Wasted energy is usually…
You use the appliance for longer and when the appliance uses a greater amount of power
It will take 8 years to pay back the cost
Created or destroyed
Is a graph showing input, useful and wasted joules
Heat or sound and goes into the surroundings
The more electrical energy it will transfer
Turns more of it’s input energy into useful energy and wastes less energy
But will save money in the long term. The time is takes to recover the cost of the device is
called pay back time
Energy transfer and efficiency