ZEMCH 2015 - International Conference Proceedings | Page 577

The bio-mimetic approach, based on the observation of the natural elements, is an essential
source of inspiration for the formulation of the specific envelope solution proposed, both for the
geometry of the façade components and for the physical properties of the employed materials.
The term biomimetics comes from the Greek word bio mimesis and to this day it means the observation of the biological kingdom, the investigation of the nature as a source of knowledge
and inspiration, and then the mimicking of the biology. This expression was coined in 1957 as the
combination between biology and technology, applied to the engineering sector (Chiesa 2010).
4. 1 Innovative envelope system
The renovation interventions tackled in the research are related to the improvement of the energetic performances of the existing recent buildings, through the increase of the thermal insulation properties and the reduction of the thermal bridges for the envelope.
In this framework, it is important to conceive a design strategy for controlling and reducing heat
loss during the cold season and for guaranteeing high level of thermal comfort and indoor air
quality, through the juxtaposition of a second skin to the existing envelope building. Technological evolution within the domains of building construction and materials technology allows
designers to reassess the traditional concept of envelope as a rigid separation barrier between
inside and outside, with the aim to conceive it like an adaptive and efficient diaphragm, according
to internal and external solicitations.
Thus, the research investigates the possibility of creating a “continuous envelope system” (Herzog 2004), meaning a second skin tailored to the existing shape, constituted of the assembly of
prefabricated panels, linked to the existing façade by mechanical punctual fixing system, in order
to create an integrated envelope system possessing efficient thermal performances. The achievement of a continuous envelope system, constituted by a close-fitting integrated skin attached to
the existing façade, leads to the maximum reduction of the heat loss bridges in relation to the
discontinuity points of the buildings.
The façade system proposed herein is conceived as a three-dimensional structure in polymer-matrix composite material, obtained through the 3D Printing process, constituting the rigid and resistant frame for containing the innovative thermal insulation material. The prefabricated panel
thus obtained is anchored to the existing wall through a mechanical punctual fixing system, in
order to upgrade the energetic performance of the existing buildings up to nZEBs.
The creation of customized façade components is based on the use of computational control
tools for managing the phases of analysis, design, fabrication and implementation of the tailored
architectural solutions, adaptable to the different morphologic and constructive characteristics of
the building. The process of information transfer from the early design phase to on site construction could be significantly simplified by the implementation of metric survey, interfaced with
parametric software and CAD-CAM technology for the digital model design, associated with CNC
machines and 3D Printers for the industrialized production of building components.
This innovative integrated approach permits to overtake the widespread use of design criteria
based on a strong formal simplification of the architectural façade solutions, leading to the development of more complex forms able to fit in with the spatial typological configuration. This
design methodology represents an advanced approach for architecture, founded on the concept
of generative component, related to the possibility of creating models operating directly on the
geometry, through the input of forms and algorithms.
The “dynamism” concerns the variability of the constructive system proposed, according to outbuilding system, mechanical and thermal analysis, constructive experimentation, test of installation techniques and
performance requirements. The exploitation of the innovative recycled insulation material (AAM) was supported by
the Research Centre CIRI – Building and Construction of the University of Bologna.

Towards nZEBs: innovative materials and technologies for new sustainable envelope

575