Civil Engineering Reference
In-Depth Information
Fig. 11
Initial data of external-wall multiple-criteria analysis
The presented alternatives include different concrete and wood wall construc-
tion (different insulation and concrete thickness, external decoration materials).
The criteria according to their significance are as follows: inertia (0,16), U
value (0,1), carbon emission (during manufacturing phase) (0,1), price (0,1), the
thickness of heavyweight layer (0,05), insulation thickness (0,05), density (0,05),
maintenance and the cumulative energy demand (results from SimaPro): non-
renewable, fossil (0,05), non-renewable, nuclear (0,05), non-renewable, biomass
(0,05), renewable, biomass (0,03), renewable, wind, solar, geothermal (0,03), and
renewable, water (0,03).
Here, thermal inertia is the key property, as it shows slowed reaction to tem-
perature variations and, as suggested by our estimates, contributes to lower heat
gains. This criterion has, therefore, the highest weight (0.16). The benefits of an
energy-efficient building design should be evaluated for the entire life cycle of the
building (Pacheco et al.
2012
). In this case, they are as follows: carbon footprint
(kg CO
2
eq) and cumulative energy demand (renewable and non-renewable), for
wall materials in the manufacturing phase.
Among the parameters that intervene in the passive solar design of buildings,
orientation is the most important and the one that has been most frequently studied.
(Morrissey et al.
2011
). According to (Pacheco et al.
2012
), the benefits derived
from optimal building orientation are the following:
• It is a low-cost measure that is applicable in the initial stages of project design.
• It reduces the energy demand.
• It reduces the use of more sophisticated passive systems.
• It increases the performance of other complex passive techniques.
• It increases the quantity of daylight, reduces the energy demand for artificial
light, and contributes less to the internal heating load of the building.
