keep your home warm

Design a house

LO – Draw a poster to design a house by using knowledge of
conduction/ convection/radiation

20/12/2022

设计要求：
Design requirement
1，地点：哈尔滨
2，2层楼

You must:

• Draw a picture of your design by using laptop

• Label it

• Describe what each part is made of

• Explain why you have chosen each material

Saving Energy

This log cabin has a snowy roof. It tells us that it
must have really good loft insulation. If it didn’t
then the snow would have melted.

The roof is insulated with
fibreglass. Fibreglass contains
air pockets which prevent heat
escaping via conduction.
As less energy escapes and more
energy stays in the house it
means it is energy efficient.

The fireplace in this house is NOT efficient.
Most of the heat conducts through the walls
out of the room. Only the heat facing
forward can get into the room.

The fireplace in this house IS efficient. The
heat radiates into the room in all directions.
Less heat is wasted so is more efficient.

For every 100J of energy released as heat only
25J are transferred to the room.

For every 100J of energy released as heat
90J are transferred to the room.

efficiency = 𝑢𝑠𝑒𝑓𝑢𝑙 𝑒𝑛𝑒𝑟𝑔𝑦 𝑜𝑢𝑡𝑝𝑢𝑡

𝑡𝑜𝑡𝑎𝑙 𝑒𝑛𝑒𝑟𝑔𝑦 𝑖𝑛𝑝𝑢𝑡
𝑥 100

efficiency = 25 𝐽

100𝐽𝑥 100 = 25% 𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡

efficiency = 90 𝐽

100𝐽𝑥 100 = 90% 𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡

www.PhysicsGCSE.co.uk

Drag and Drop

efficiency = ​ ​

Placeholder

/​

Placeholder

x ​

Placeholder

Drag these tiles and drop them in the correct blank above

useful energy output

total energy input

100%

Sankey Diagrams

Sankey diagrams are used to show
energy transformations.

Inside the arrow
shows the TOTAL
INPUT energy

An arrow to the right
shows the USEFUL
energy output.
Remember: there
may be more than
one arrow so you
would need to add up
all of the values

An arrow pointing downwards shows the
WASTE energy output.
Remember: there may be more than one
arrow so you would need to add up all of the
values

The values outside = the values inside.

100J = 10J + 90J

The light energy arrow is 9 times
smaller than the heat energy arrow.
This is because 10J is 9 times smaller
than 90J. This means the Sankey
diagram is to scale.

www.PhysicsGCSE.co.uk

Multiple Choice

Where does most of the energy go in this transformation.

• Electrical energy

• Light

• Heat

• other

Multiple Choice

Where does most of the energy go for this transformation.

• heat

• electrical

• light

• joules

Multiple Choice

What is this diagram called?

• Stankey Diagram

• Sankey Diagram

• Sankay Diagram

• Samkay Diagram

Multiple Choice

The energy efficiency shown in this diagram is:

• About 10%.

• About 30%.

• About 60%.

• Impossible to tell.

Payback Time

There are many ways a home loses heat:

Roof Walls Doors Floors Windows

The house is the source of the energy

The atmosphere is the sink. It can
absorb lots of energy without changing
its temperature by very much.

The Payback Time equation will
tell you which insulation method
is the most cost-effective.
𝑃𝑎𝑦𝑏𝑎𝑐𝑘 𝑇𝑖𝑚𝑒 𝑦𝑒𝑎𝑟𝑠 = 𝑐𝑜𝑠𝑡 𝑜𝑓 𝑖𝑛𝑠𝑢𝑙𝑎𝑡𝑖𝑜𝑛

𝑎𝑛𝑛𝑢𝑎𝑙 𝑠𝑎𝑣𝑖𝑛𝑔

Insulation

Typical cost in
£

Typical annual
fuel saving in £

Cavity wall

250

125

Double glazing

5000

100

Loft

250

150

Double glazing

𝑃𝑎𝑦𝑏𝑎𝑐𝑘 𝑇𝑖𝑚𝑒 𝑦𝑒𝑎𝑟𝑠 = £5000

£100 = 50 𝑦𝑒𝑎𝑟𝑠

This means that it will take 50 years to earn back the initial start up
cost of £5000. After 50 years all savings are profit.

Cavity wall insulation only takes 2 years to pay back the initial cost

www.PhysicsGCSE.co.uk

Multiple Choice

If a solar panel costs $3000 to install and saves £150 a year, what is the payback time in years?

• 15 years

• 2 years

• 10 years

• 20 years

​Quiz Time

Fill in the Blanks

Draw

Draw a Sankey diagram for a lightbulb that has 100 J of electrical energy that transfers into 75 J of useful light energy.​

Design a house

LO – Draw a poster to design a house by using knowledge of
conduction/ convection/radiation

20/12/2022

设计要求：
Design requirement
1，地点：哈尔滨
2，2层楼

You must:

• Draw a picture of your design by using laptop

• Label it

• Describe what each part is made of

• Explain why you have chosen each material