Civil Engineering Reference
In-Depth Information
3 Life Cycle Assessment of the Leaf House
3.1 Goal and Scope Definition
The energy and environmental performances of the LH are assessed applying the
life cycle assessment (LCA) (Ardente et al.
2005
; Battisti and Corrado
2005
;
Brown and Aaron
2001
), in compliance with the international standards of the ISO
14040 series (UNI EN ISO14040
2006
). In particular, the main goals of the study
are as follows:
• to assess the energy and environmental impacts owing to all the life cycle phases
of the building in both scenarios of analysis;
• to assess the net primary energy saving achievable in Scenario 2;
• to evaluate whether the energy saving involved in Scenario 2, and the conse-
quent avoided environmental impacts would offset the increased embodied
energy of the building and the related life cycle environmental impacts.
The life cycle impact assessment (LCIA) is carried out by means of the envi-
ronmental indicators and characterization factors of the EPD scheme (environ-
mental product declaration—EPD) (The International EPD
2008
). Other indicators,
on which there is not any scientifically agreed calculation method in the LCA
context, such as human toxicity, ecotoxicity, biodiversity, and land use, are not
included. Energy consumption in the building life cycle is calculated as primary
energy, which represents the most effective indicator to express consumption of
energy under different forms. This calculation took into account all the losses
related to the processes of extraction of the resources, their transformation and
distribution and requires the assessment of electricity and fossil fuel uses, according
to different efficiencies in the final uses (heating, DHW, lighting, etc.). Cumulative
energy demand method is used to account for the overall primary energy require-
ment of the assessed actions (PRè-Product Ecology Consultants
2010
).
3.2 Definition of the Functional Unit and System Boundaries
The selected functional unit for the LCA study is the whole building in both the
assessed scenarios are referred. With regard to the system boundary, the assessment
of the energy and environmental performance in both scenarios covers upstream
and downstream processes needed to establish and maintain the function of the
building. The reference study period and the required service life of the building are
assumed the same. To this purpose, the energy and environmental impacts arisen
from the following stages of the building life cycle are taken into account:
• production of the building, which includes the production processes of all the
building-related materials and components, and the construction step of the
building, taking into account raw material acquisition and resource supply.
