Environmental Engineering Reference
In-Depth Information
extract stale air from kitchens and bathrooms. The stream of fresh air is run from
outside through a cross-heat exchanger past the vitiated air. The stale air emits up
to 90% of its heat to the cold, fresh air from outside. So the heat remains in the
building. The same system can be used to keep a building cool when outdoor tem-
peratures are high.
Controlled ventilation is often perceived as having a negative effect on living
conditions, but the opposite is actually the case. A gentle draught from such a
system is barely noticeable. Constant optimal ventilation prevents dampness forming
in walls or mould building up. An air fi lter in the ventilation system will keep out
some of the pollutants in the outside air and also make it diffi cult for insects to get
inside. Of course, anyone who feels that it is necessary can open the windows
anyway - even if this is really no longer necessary from a practical point
of view.
An air supply system can also be combined with a ground heat exchanger. This
involves laying a pipe through the soil in the garden to supply incoming air. In
winter the soil heats the fresh air and in summer it cools it.
An ultra high energy-saving house requires an outlay of additional costs, but over
the years these costs pay for themselves as energy prices rise. In some countries,
such as Germany, banks offer particularly good low-interest loans to promote
energy-saving measures in new houses and in the renovation of old buildings. In
principle, those who want to keep heating requirements carbon-neutral have the
following options:
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Solar thermal systems
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Biomass heating
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Heat pumps using electricity from renewable energies
■
Heating systems based on renewable hydrogen
Solar thermal systems usually supplement other types of heating. Later chapters in
this topic discuss these different variants in detail. As the potential for certain pos-
sibilities such as biomass heating is limited in many countries, the other options for
saving energy described above should be implemented as far as possible before
renewable energies are used.
3.2.3 Transport - Getting Somewhere Using Less Energy
The transport sector is responsible for about one-fi fth of carbon dioxide emissions
caused by energy use. Whereas it seems that major savings can be achieved rela-
tively quickly with electricity use and in heat generation, the transport sector is more
problematic. In recent years increased mobility and the travel bug have managed to
cancel out any savings in the fuel consumption of cars and aeroplanes. Cheap air-
lines that sometimes offer plane tickets for the price of an underground fare and the
trend towards petrol-guzzling SUVs are prime examples of this development. Added
to this are the even longer distances involved in transporting goods around the world
as a result of globalization.
