E n e r g y R e c o v e r y o f ‘ 7 0 e s I n d u s t r i a l i z e d B u i l d i n g
521
The thermal resistance of each functional layer is given by the ratio between
the layer
thickness, s (mm), and its coefficient of thermal conductivity,
λ
(W/mK)
λ
s
R
=
Considering the values of
λ
taken
by UNI
10351 and
UNI
10355,
concerning
the
thermal resistance
per
unit area for the most widespread enclosures in Italy and the UNI
EN ISO 6946 for the resistance of cavity walls, ventilated or not, less than 30 cm
thickness and less than 10% of the other two dimensions, the calculations were carried
out and shown in the following diagram (Fig.8).
Comparing the values of transmittance for vertical and horizontal enclosures determined
with the minimum defined by current regulations, it is clear that such buildings provoke
currently considerable energy dispersions, thus requiring a series of interventions to
decrease the high consumption required for management.
Energy saving and environmental interventions
The proposed intervention strategy for energy saving and environmental improvement of
the buildings made by industrialized techniques is based on active intervention,
modifying in part the technical solutions, and passive interventions, taking into account
the exposure, the shape of the buildings and the possible use of vegetation.
The main objective of the sustainable recovery is to find in the broad range of energy
solutions available, the best ones integrating with the existing and certainly not altering
the architectural appearance of buildings. Based on the analysis of critical points
previously analyzed, the design focuses on interventions aimed at improving the energy
performance of several technical elements of the envelope and the elimination or
reduction of thermal bridges effects, due to couffrage-tunnel technology.
Two different types of intervention have been planned for the walls, according to the
different construction characteristics and thermal properties of the transverse and
longitudinal walls.
The main intervention consists in the realization of green wall linings, covering all the r.c.
walls with no windows (approximately 250 square meters), both exposed to north-west,
south-east, north-east and south-west, getting different energy performance depending
on the exposure.
This choice derives both by energy requirements and architectural planning. This "green
wall", in addition to functioning as a climate moderator, allows a better integration
between the building and the natural landscape, giving benefit to the people of the
district, thus improving the livability and ambience of the outdoor spaces between
buildings (Fig.7).
Moreover, this intervention does not change, in a sense, the architectural image of the
buildings as merely turning the r.c. solid front into an equally solid one, but rich of plants,
to recall the historic buildings covered with ivy.
The green wall lining is constituted by a support structure made of a metal grid panel on
which plants will be able to climb and develop in height. The peculiarity of this panel is
that on the back side is made of polystyrene sheets creating an outer coating, protected
by the vegetation.
The wall lining has to be joined to the existing r.c. wall through stainless steel supports
as not to produce oxidation processes. Depending on the chosen plant species, it is
expected the possibility to fix containers at different heights or placing, in the case of
climbing plants with aerial roots (ivy, Virginia creeper, etc.), containers at the base of the
wall or directly bury the plants in the soil.
