ZEMCH 2015 - International Conference Proceedings | Page 593

els have almost homogeneous requirements and how it is highly competitive with the other ones
on the market.
Furthermore, also the evaluation of the dynamic parameters, fundamental in the assessment of
the system answer in warmer cities, as the case of Palermo, confirms the possibility to use the new
panel with good results.

Conclusions
To determine the convenience of an insulating material, as in the exsaminated case study, depends on the ability to achieve certain benefits, for a given mass in each case. However, the choice
of the most suitable material strongly influences the degree of “sustainability”.
For example, to determine how a material is ecological, it is necessary to take in account several
factors, such as the production steps, the way from the manufacturing and all that makes the
material ready for marketing: thus carrying out an energy balance of the life of the insulating
material - emissions for the production, emissions for the transport, lower emissions due to the
isolation of the material - could result that a material of chemical origin, such as EPS, in addition
to having one of the greatest values of insulating capacity, it is more ecological of some “natural”
materials requiring little energy for the production, but that may be subject to warping for thermal expansion in the process of its implementation.
Even in the case of materials of mineral origin it could be possible to present disadvantages as in
the case of rock wool, for which is required a fusion of the raw material at elevated temperatures
(about 1400 °C) and, if not properly applied and protected from moisture, the thermal performance is drastically reduced.
Furthermore, to obtain a certain stability of the panel shape, the fibers are mixed with the binder
bakelite, a phenolic resin that releases formaldehyde.
Similarly, the wood fiber must be subjected to very onerous treatments before they can be used.
It means that a cost-benefits analysis is the key strategy to assess the most suitable solution, case
by case, and that a natural and innovative panel, such us the Opuntia ficus-indica, may reach very
high energy performance with low cost of implementation, and the possibility to exploit a natural
material, usually wasted (Figure 8).

Figure 8: Waste materials

Eco-friendly materials for the energy retrofit of existing buildings

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