Nano-structured Materials in New and Existing
Buildings: To Improved Performance and
Saving of Energy
F. Scalisi 1
Abstract. Improving well-being in buildings, in relation to energy conservation,
represents a great challenge. In southern Italy a basic problem is that of keeping
buildings cool in the summer months. This problem affects not only newly-erected
buildings, but also the large number of existing buildings, some of which are of historical importance. Nano-technology represents an excellent opportunity to harness
the salvage of existing buildings to the living requirements of contemporary society. The use of nano-structured materials in newly-erected buildings will lead to
improved performance and a considerable saving of energy. Above all, the use of
nano-structured materials in existing buildings will provide the possibility of intervention in these buildings and help improve, for example, insulation or lighting,
without invasive intervention and consequent damage to the building itself.
1 Introduction
Nanotechnology is about the manipulation of matter at the nanoscale. A nanometre is a billionth of a metre (m=10-9 m). It is an 80.000th of a diameter of a
hair. Nanotechnology opens up new possibilities in material design. On this level
material behaves differently to how it does on the macro-level; objects can change
colour and shape much more easily and fundamental properties such as force, surface/mass relationship, conductibility and elasticity can be improved in order to
create material that can provide a better performance than present ones. The possibilities provided by nanotechnology embrace the most disparate sectors, from
electronics to medicine, from energy to aeronautics, to name but a few; building is
one of these and is considered a promising area of application for nanotechnology.
The considerable modifications in materials and, consequently, building processes
F. Scalisi
University of Palermo, Department of Progetto e Costruzione Edilizia – DPCE
e-mail: francescascalisi@gmail.com
352
F. Scalisi
indicates that nanotechnology can provide radical and systematic innovation in
architecture; the extent to which, and the manner in which architects, engineers,
researchers, builders and producers embrace this innovation will determine the future of architectural operations.
2 Nanostructured Materials for the Energy Efficiency of
Buildings
In the architectural sphere the advent of nanostructured materials is considered decisive for the energy efficiency of buildings. Nanotechnology provides new technological means with which to tackle climatic changes and contribute to reducing
gas emissions in the near future. The first phase of the Kyoto Protocol will end in
2012 and CO2 emissions throughout the world will have to be halved by 2050. Energy efficiency in buildings is therefore indispensible, especially since constructions are one of the major producers of CO2 emissions. Architects are called to
find innovative solutions in order to slow down climatic change, combining the
requirements of dwelling-areas with energy efficiency.
One of the basic problems linked to energy consumption in buildings is represented by winter heating and summer cooling. Heat-loss and gain are closely connected to the presence of glass surfaces and to the insulating capacity of the outer
cladding. As regards glass surfaces, nanotechnology is reducing heat-loss and gain
by using glass covered with layers of thin thermo-chromatic, photo-chromatic and
electro-chromatic film. Thermo-chromatic technology is capable of varying its
own light absorption in function of its external surface temperature, becoming
opaque above a certain critical temperature and then becoming transparent again
with a fall in temperature.
Photo-chromatic technology autonomously modifies its light transmission in
function of the amount of incident light on its surface. Lastly, electro-chromatic
cladding gradually varies its own transmission in function of an electric signal; in
order for the glass to become transparent again a new backward electrical impulse
signal is required. All these applications are intended to reduce the use of energy
for heating and cooling buildings and might contribute to helping diminish energy
consumption in buildings.
Another category of material that has received a great boost from the arrival of
nanotechnology is that of cladding/coating. Insulation coating represents a field of
notable importance for the application of nanotechnology; it heralds the creation
of materials with a greater insulating action than conventional insulation, but of a
lesser thickness.
These performances characterise Vacuum Insulation Panels (VIP), which
are capable of guaranteeing the same thermic transmittance as traditional insulation with a thickness that is ten times inferior; they are made up of a nucleus of
Nano-structured Materials in New and Existing Buildings
353
Fig. 1 Vacuum Insulation
Panel (VIP)
material of low thermic conductibility, which can be subjected to high pressure,
whilst the cladding is made of plastic or extremely flexible and resistant metals.
Research has highlighted the need, apart from great resistance to compression and
low thermic conductibility, for the central nucleus material to be characterised by
a high degree of porosity, in order to facilitate the passage of air; therefore, importance must be given to the size of the pores, which must be less than 100 nanometres, in order to avoid phenomena of thermic gas conductibility.
“Aerogel is an ultra-low density solid, a gel in which the liquid component has
been replaced with gas. Aerogel has a content of 5 percent solid and 95 percent
air, and can support over 2,000 times its own weight. Aerogel panels are available
with up to 75 percent translucency, and their high air content means that a 9cm
(3.5”) thick aerogel panel can offer an R-value of R-28, a value unheard of in a
translucent panel. One of the greatest potential energy-saving characteristics of
nanocoatings and thin films is their applicability to existing surfaces for improved
insulation. Adding thermal insulation to existing European buildings could cut
current building energy costs and carbon emissions by 42 percent or 350 million
metric tons” [2].
Nanotechnology promises to render insulation more efficient, less dependent
on non-renewable resources and less toxic. Producers estimate that insulation materials deriving from nanotechnology will be about 30% more efficient than those
from conventional materials.
One of their most important characteristics of insulation nano-coating is its
applicability to existing surfaces to improve their insulation; it can be applied
354
F. Scalisi
directly to the surfaces of existing building, whilst the post-construction addition
of conventional insulation materials such as cellulose, glass-fibre, polystyrene is
extremely invasive.
Its application to existing structures could lead to huge savings in energy and it
does not seem to pose a threat to the environment and health in the way that glassfibre and polystyrene do.
Nanotechnology promises to render insulation more efficient, less dependent
on non-renewable resources and less toxic.
Fig. 2 Silica aerogel
Table 1 Example of masonry in a building in Sicily
Masonry
Thickness
External plaster of lime and gypsum
mm 30
Extruded polystyrene foam
mm 40
Brick (250x120x50)
mm 120
vertical layer of air
mm 60
Brick (250x120x250)
mm 120
Internal plaster of lime and gypsum
mm 20
2
Transmittance is 0531 W/m K with a thickness of 390 mm, with an insulating
nanostructured could have a better transmittance with a lower thickness.
Nano-structured Materials in New and Existing Buildings
355
Fig. 3 Aerogel with glass
3 Conclusion
It should be pointed out that buildings are responsible for a quarter of carbon
emissions in the European Union, 70% of which stems from heating requirements.
By saving on the heating of spaces through better insulation, the European Union
could reduce carbon dioxide emissions by 100 million tonnes per year, and by so
doing ensure that Europe alone might reach its goal of reducing carbon emissions
by 25% by 2010. In spite of its enormous potential, there are several factors that
might impede the adoption of nanotechnology on a large scale: above all the high
cost of nano-products compared to conventional ones. Nanotechnology does represent a relatively recent accomplishment and prices are destined to fall, as is usually the case, over the course of time, with all new technology. Secondly, the
building market is extremely conservative and therefore tends to proceed cautiously in adopting new technologies; those in the trade seem to know very little
about nanotechnology and its potential implications for the building sector.
Knowledge and skills are still too fragmentary to enable it to spread extensively in
the building sector. Moreover, from the point of view of demand, there will be a
certain reluctance regarding the introduction of nanotechnological materials until
convincing documentation is produced regarding its functionality and the longterm effects. Finally, there is considerable anxiety about the general public’s
seeming reluctance to accept nanotechnology.
356
F. Scalisi
References
1. Alagna, A.: Energie & tecnologie in architettura, ricerche per una possible casa passive
in Sicilia. DPCE, Palermo (2004)
2. Elvin, G.: Nanotechnology for Green Building. Green Technology Forum (2007)
3. Hegger, M., Fuchs, M., Stark, T., Zeumer, M.: Atlante della sostenibilità. UTET, Torino
(2008)
4. Leydecker, S.: Nanomaterials in Architecture, Interior Architecture and Design. Birkhäuser, Basel (2008)
5. Mann, S.: Nanotechnology and Construction. Nanoforum (2006)
6. Sala, M.: Recuperoedilizio e bioclimatica. Sistemi Editoriali, Napoli (2001)
7. Scalisi, F.: I materiali nanostrutturati nel settore edilizio. In: Sposito, A. (ed.) Agathòn,
vol. 2, Offset Studio, Palermo (2008)
8. Scalisi, F.: Nanotechnology in construction: the new means for the sustainable development. In: Fabris, L.M.F. (ed.) Enviroscape a manifesto. 2nd blu+verde International
Congress, Maggioli, Rimini (2008)