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is differentiated by in this figure. For apartment buildings, a discernible correlation
between embodied energy for the building construction and the compactness of a
building can be seen. However, there is practically no correlation between these
parameters for single family buildings. The values for light weight and heavy weight
buildings also do not show any strong bias, e.g. that light weight buildings have a
significantly lower amount of embodied energy as compared to heavy weight buildings.
This often stated “fact” could not be verified with the data available.
Figure 4: Correlation of embodied energy for building construction and building compactness
depending of the construction style of the Minergie-A buildings.
3. From Minergie-A towards Net ZEB
3.1 Operational and embodied energy
The step from the Swiss Minergie-A standard to a net zero energy building is not a very
big one. Simply increasing the size of the photovoltaic system is sufficient in most cases.
Some of the Minergie-A buildings evaluated are also net zero energy buildings, anyway.
In this paper, net zero energy buildings (Net ZEB) are defined as buildings that
•
cover their total annual operational energy load,
•
generate this on site by renewable sources,
•
typically use photovoltaic systems and
•
do not include the embodied energy in the balance, today.
The following analysis focuses on studying the trade-off between embodied and
operational energy due to additional photovoltaic panel area necessary to take the step
from Minergie-A to Net ZEB.
As a starting point, the Minergie-A buildings as described are used. The embodied
energy is calculated based on non-renewable energy as before. The operational energy
is recalculated based on non-renewable primary energy (table 2). It must be noted, here,
that the factors used are from two different sources, each of which focus on slightly
different goals / are influenced by different interests. Setting out from this starting point,
two different building configurations are considered:
