Civil Engineering Reference
In-Depth Information
embodied energy given in verified EPD for a component from a specific manu-
facturer, which will take into account its sourcing and production process, and
therefore would promote those products with less associated embodied energy.
Some EPDs could even provide information beyond the factory gate, that is, about
the construction process or recyclability potential of the product, which could
serve for more detailed analysis in an extended methodology, following a meth-
odology such as described in the standard EN 15978:2011 already commented in a
previous section.
Taking into account both uncertainty and sensitivity of both issues (energy
performance in use and embodied energy) at the same time, it has to be noted that
some variables that affect the building use phase, and can be analysed through
energy performance evaluation, also have an effect on the other phases of the
building and on the embodied energy calculations, adding complexity to a sen-
sitivity analysis. For example, a detailed analysis could show that depending on the
user ventilation or temperature preferences, certain building solutions might be
possible with less services and systems, therefore having less embodied energy.
An analysis of all those questions together and performing a sensitivity analysis of
their interaction and implications would require specialized software that at the
moment, to the knowledge of the author, is not yet available. In the meantime, the
proposed simplified methodology such as the one presented has as the intention is
to be understood and preliminary applied taking into account the recognized
uncertainty on the sources and sensitivity of the results. As data sources are
improved, this method could be applied by relevant stakeholders on building
refurbishment, from architects and engineers who could use the methodology for
design advice, to policy makers who could use it to improve building energy-
related policies, such as the establishment of requisites, goals and funding schemes
for building refurbishment projects.
6 Discussion and Conclusions
This chapter has presented a methodology to account for life cycle energy per-
formance evaluation in building refurbishment projects, by integrating existing
building energy evaluation methods with embodied energy calculations. Using the
methodology, the life cycle energy savings of different refurbishment strategies
can be compared and analysed, with a wider perspective than looking solely at the
energy performance of the building during the use phase. Taking into account this
life cycle perspective, there is a recommendation for giving more attention to the
types of materials and systems used on refurbishment projects that have the
objective of moving towards 'zero energy' or 'net zero energy'. While
approaching the zero-energy goal, the life cycle energy savings must be considered
and perhaps the objective needs to be redefined as refurbishment for LC-ZEB,
