Functional Maths
Task 1
Reducing Carbon Footprint
Energy Labels
New electrical equipment has energy labels that show a rating for energy efficiency, based on
how much energy they use.
A is the most energy efficient and G is the least energy efficient.
These labels allow us to make a choice about the energy efficiency of what we buy.
Here are two labels for fridge-freezers with different energy efficiency ratings.
1
(a) Which of the two fridge-freezers is the less energy efficient?
(b) How many kilowatt hours (kWh) of energy is used by the Freezepoint RF70
in a year?
(c) One kilowatt hour (kWh) of energy costs about 10p.
On that basis, approximately how much money would the more energy
efficient fridge-freezer save in a year, compared to the other one?
This table shows some information about five fridge-freezers
2
(a) Three of the fridge-freezers in the table do not have an Energy Rating.
One should have an A rating, one a B rating and the other a C rating.
Show on the table which fridge-freezer should have which Energy Rating.
(b) A customer wants the most energy efficient fridge-freezer they can afford.
The annual energy consumption must be less than 400 kWh/year.
The fridge capacity must be at least 200 litres.
The most they can spend is £300.
Which of these five fridge-freezers should they buy?
(c) One kilowatt hour (kWh) of energy costs about 10p.
On that basis, after how many years will the total costs of the Vortex (the price to buy plus the
cost to run) become less than the total costs of the Coolmaster?
_______________________________________________________________
Task 2 British Thermal Units and CO2 emissions
The effects of global warming and increasing costs of energy are likely to affect
everyone. In this activity, a family is trying to reduce carbon emissions. They
have been told that by reducing their thermostat by 1C, they can save 10%
Mr & Mrs Turner have asked you to give them advice about reducing the amount
of CO2 emissions from their central heating system. In this task you have to
calculate an estimated figure.
This is a plan of their bungalow. Each
square represent 1 square metre
This table shows the minimum radiator
output required per hour in British
Thermal Units (BTU) for room of various
areas
The
Room Area
m2
6 area <8
8 area <10
10 area <12
12 area <14
14 area <16
BTU
1800
2100
2400
2700
3000
Turner's have a radiator in every room except the hall
1 Calculate an approximate value for the BTU (per hour) they will need for each
room
They run their heating from 6am to 8am and from 4pm to 10.30 on weekdays
and from 6.00am to 10.30pm on weekdays.
2. Estimate the number of BTU's they use each year
3. If one and a half million BTU is roughly equal to 60kg of carbon dioxide gas
(CO2)
How many tonnes of CO2 does the Turner’s heating system produce each year?
Task 3
The Turner's have two teenage children. Their annual bills are
Electricity £540, Gas
£720,
Water
£640
Assuming that their use of energy other than heating produces 1 tonne of CO2
per year
Use the table below (or search the internet) which shows the cost, saving per
year(£) and savings in C02 per year of various energy saving methods to write a
report to the Turners outlining the costs, savings and how long it would take
them to get their money back if they bought a new set of energy saving
appliances, for example.
You do not have to include every energy-saving measure in your report!
Action
Turn down the heating by
1C
Switch off electrical
appliances when not in use
Turn off the tap when
cleaning teeth
Dry clothes on a line not a
tumble dryer
Draught proofing
Use a shower instead of a
bath
Set hot water to 60C
Use energy saving bulbs
Use Savaplug on fridge
Fill kettle with only as much
water as required
Replace old appliances with
energy efficient ones
Double Glaze windows
Fill up the dishwasher before
using
Insulate the loft
Annual CO2
Saving
330kg
Annual
cost saving
£40
Total Cost
153kg
£40
nil
nil
311kg
£7 per
person
£15
150kg
£25
DIY cost
£90
nil
145kg
40kg
100kg
48kg
£22 per
person
£10
£9
£12
nil
nil
nil
49p each
£25
nil
85kg
£70
£300
720kg
£110
approx
cost £400
per room
nil
£15
1tonne
£150
Install solar power (See
spreadsheet)
1.2 tonne
Half the
electric bill
Fit foil behind radiators
Install a wind power
generator
51kg
250kg
Insulate cavity walls
800kg
£10
One third
of electric
bill
£120
£250
(DIY)
£12000
less FIT
income
£15
explore
£500