3.1 Light bulbs

1
3.1 Light bulbs

• As an illustration, lets have a closer look at
  light bulbs.
• The following video will illustrate to you all
  the LCA steps detailed until now, and will stop
  each time you will have a question to answer.

Video start...
0655 to 1243 people to consult 1348 to 1440
what is the system function? STOP 1440 to 1452
answer 1452 to 1457 what is the secondary
function? STOP 1457 to 1734 answers 1734 to
1842 what is the functional unit of the
system? STOP 1842 to 2031 answer 2031 to
2035 STOP
To ensure a service of 6000 hours at 600 lumen,
what do you need to buy? (your reference flows)
One economic light bulb or 6 incandescent bulbs
and 6 60W 1000h 360kWh for incandescent
bulbs 11W 6000h 66kWh for low energy bulb
2035 to 2746 answer with description of low
energy bulbs
2
3.2 Light bulbsenvironmental key parameters
2746 to 2757 what are the key
parameters? STOP 2757 to 3208 answers

• the number of lumen per watt (performance of the
  bulb),

• the life time.

The former has to be maximized for the use phase.
The latter directly influences the environmental
load for the raw material extraction and the
manufacturing stage. Further analysis is however
required to assess the relative importance of
these different development stages.
3
3.3 Light efficiency for different sorts of bulbs
3208 to 3441 properties of bulbs through time

• Beware comparing an emerging technology which has
  not yet been optimized with a well established
  one which has been improved over years.
• On the second graph, you can see that efficiency
  of light bulbs has improved of a factor 1000 over
  100 years. Turning a new technology into an
  efficient one requires time.

4
3.4 Light bulbseconomical considerations
3441 to 3646 problems with those bulbs
Price is often raised as a main objection, since
the low energy bulbs are more expensive.
3646 to 3710 what is the price? STOP 3710 to
4616 answer and remarks

• But the purchasing cost is not the only one that
  has to be considered. The whole economic costs
  can easily be calculated and compared on the
  basis of the same FU, applying a life cycle
  costing approach
• an incandescent bulb is about 1,
• low energy fluorescent bulbs cost 10 each,
• electricity is about 0.1/kWh (use phase).
• Please feel free to calculate the corresponding
  investment costs