3-12 Sustainable energy knowing more (3.4)

Sustainable energy (knowing more)
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NatuurkundeMiddelbare schoolhavo, vwoLeerjaar 2

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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?

Slide 11 - Diapositive

Make question 66a
timer
2:00

Slide 12 - Diapositive

Homework:
66 b,c
67

no discussion

Slide 13 - Diapositive

Slide 14 - Diapositive