Civil Engineering Reference
In-Depth Information
Table 1.2: Renewable sources and the levels of energy
Mechanical
Electri-
Heat
energy
city
Above
Between
Between
Temperatures
600°C
200-600°C
100-200°C
under 100°C
(room
temperatures
and hot water)
Sun
(x)
(x)
(x)
(x)
x
x
Water/wind/waves
(x)
x
x 1
x 1
x 1
x
Wood and peat
(x)
x
x
x
x
District heating
x
Notes:
x: commercially available industrially
(x): under development
x 1 :
from electricity
burning in shaft furnaces needs 10-40 per cent less energy than traditional rota-
tional furnaces. In the steel industry one could reduce the use of energy by 50 per
cent by changing from open blast-furnaces to arc furnaces.
Energy saving during the building process
Local materials
The use of local materials means less transport requirements.
Low energy materials
Give priority to materials that have a low primary energy consumption and are
durable.
Labour intensive processes
The energy needed to keep a worker and his family is so small that it has little
effect in the total energy calculation. Labour intensive processes are almost with-
out exception energy-saving processes.
Natural drying out of the building
There is a lot to be gained by choosing quick drying materials - brick rather than
concrete, for example - and by letting the building dry out naturally.
Building techniques that favour re-use and recycling
Most building materials have used a great deal of energy during manufacture. By
re-using seven bricks, a litre of oil is saved! Recycling metals can save between
 
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