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Energy house, you may ask which of these efforts could be applied to the geographical climate,
economy, and social circumstances here in Hong Kong. Of course, I have to leave this question
to the domestic experts.
2.2.3 Example of Refurbishment
In the following slides I would like to give you an impression of a quite usual, normal
refurbishment measure which was finished this year in the city of Freiburg, which is situated in
the south of Germany, close to the border of Switzerland and France. What you can see here
is a high-rise residential building. It comprises 16 floors, was constructed in 1968, and some
key data of the building before refurbishment you will see on this slide. You will see here a list
of building measures which took place in the last two years, such as building more balconies,
external sun-blinds, new windows, and so on. Some of the results are as shown; more
dwellings, partly handicapped accessible, balconies, and other things.
An advanced insulation system was also built, which was very important in this case, and as a
result the building now reaches the limits of so-called Passivhauses in Germany. In particular,
considerable reductions of energy demand were achieved. You will see here 80 percent
reduction of heat energy demand, and I won't give you anything in detail as I was told that
through the good help of Civic Exchange you will have these slides on the home page of Civic
Exchange afterwards. 1
Most users of building contractors are not construction experts, neither energy experts.
Energy performance certification must be explained in a way that is understandable to the
layperson. As with consumption in the case of cars, energy demand with regard to buildings
must be presented in clear and concrete terms. To this end, the Energy Saving Ordinance
stipulates the issuing of energy performance certificates for all new buildings or when selling
or releasing an apartment or building.
Public buildings must now display these certificates in a clearly visible location. The German
Parliament and Government must lead the way by example, of course. The Reichstag Building,
the seat of our parliament, was constructed in 1894, yet the building's current energy demand
is superior to the energy efficiency levels of comparable new buildings.
2.3 About Energy Saving Construction – Plus Energy Houses
I come now to the topic of the Plus Energy houses. Plus Energy means in this context that in my annual
energy balance I can provide more renewable energy than is needed to operate my building. These
objectives cannot simply be achieved by means of large, renewable energy systems. A range of
measures is needed. Construct compact structures and orientate them so that they can take optimal
use of solar energy. Ensure an especially high standard of thermal installation, including windows.
Avoid thermal breaches. Make the building envelope airtight. Install ventilation systems with heat
recovery. Realize low heating system temperatures, short pipe length, and hydraulic balancing of the
systems. Use efficient heating devices and domestic appliances. Make use of the daylight, and use
efficient technology for artificial light. Realize usage patterns for occupants, so that they actively
participate in the process of energy conservation.
Along with these passive measures, it is also necessary to realize active measures. These involve in
1 See www.civic-exchange.org/wp/111101/
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