Cette leçon contient 14 diapositives, avec quiz interactif et diapositives de texte.
La durée de la leçon est: 50 min
Éléments de cette leçon
Sustainable energy (knowing more)
Slide 1 - Diapositive
Efficiency
You wnat to collect the maximum
amount of energy from the sun.
At a powerstation only a small amount of the energy of fossil fuels is converted to electricity.
A lot of energy is transported away with the waste water
(60% of energy is lost)
Slide 2 - Diapositive
Efficiency
Efficiency is how well energy is being used.
example:
Of 100J only 70J is used.
The efficiency is thus 70%
The efficiency of a powerstation is therefore 40%
Slide 3 - Diapositive
Efficiency
The efficiency of a high-efficiency boiler is 95%
Less than 5% goes lost
The quest for greater efficiency...
Solar cells in 1954 had an efficency of 4%.
In 2010 a solar cell was made with an efficiency of 42%
Also importnat: - It must be cheap to produce
- Materials needed for production must not be in short supply
Slide 4 - Diapositive
Sustainable from start to finish
You heat up water with an electric kettle. So you dont produce CO2 . Is this sustainable?
Slide 5 - Diapositive
Explain if driving an electric car is sustainable.
Slide 6 - Question ouverte
Calculating efficiency:
If a solar collector converts 14 MJ energy of the possible 45MJ energy into heat, what is the efficiency?
Slide 7 - Diapositive
Make question 64
p 144
timer
2:00
Slide 8 - Diapositive
Using efficiency in calculations:
If the efficiency of an electric central heating system is 82%, and 15 m3 of natural gas is burnt, how much energy is then converted into heat by the electric central heating system?
Slide 9 - Diapositive
Make question 65
timer
3:00
Slide 10 - Diapositive
Using ration tables:
If the efficiency of a central heating system is 76%, and 56MJ of energy is converted into heat during one shower, how much energy is needed in total for one shower?