## 3 Results and Discussion
### Discussion  
In order to optimize the final mixing of the experimental panels, a cross-comparative analysis was performed taking into account both the aspects (thermal performance and environmental impacts). This multivariate analysis was carried out for each type of panel: the thermal conductivity values (\(\lambda\)) and the Global Warming Potential (GWP) were shown by the percentage change of the loose materials in the final composition of the panel. The analysis is also useful in order to find, for each type of panel, the best mixture able to ensure the best thermal and environmental performance (Figure 4). For panels types 4, 5, and 6, composed of 3 or more waste materials, the percentage of Cork was considered and the complementary one was equally divided among the other two or three raw materials.  
For panel 1 the best possible compromise between thermal and environmental performance is 37% of Cork and 67% of Rice Husk (\(\lambda\)-value equal to 0.063 W/mK and GWP 2.17 kg CO\({}_{2\text{ eq}}/1\) m\({}^{2}\)), whereas for panel 2 50% of Cork and 50% of Coffee Chaff is a good mixing solution. In general, the composition chosen for panel 3 does not represent a good insulating solution and also the environmental properties are not advantageous. The best solution, in this case, is represented by the only Cork in the mixture. For panel 4, the best compromise is the mixture composed of 30% of Cork, 35% of Rice Husk and 35% of Rubber, with a thermal conductivity that is not much higher than 0.07 W/mK. Panel 5 can be considered advantageous with a composition of 58% of Cork, 21% of Rice Husk and 21% of Coffee Chaff: 0.066 W/mK for thermal conductivity and 2.2 kg CO\({}_{2\text{ eq}}/1\)m\({}^{2}\) for the carbon footprint analysis. This is the best solution together with the best mixture found in panel 1 (minimum \(\lambda\) and GWP). Finally, the best mixing for panel 6 is 30% of Cork, 23% of RH, 23% of CC, and 23% of ELT, respectively.  
For the sake of clarity, the data with the best solution identified by this analysis are summarized in Table 8. The same analysis could be carried out also in terms of Embodied Energy for the construction of 1 m\({}^{2}\) of panel.  
The results are very similar and the data about the identified best mixtures are shown in Table 9: for panel 1 the best behavior is obtained with 43% of cork (instead of 37% for GWP), with about the same \(\lambda\) (0.062 W/mK). For panel 2 a mixture of 50% of cork and 50% of CC is a good compromise. As in the first analysis panel 3 is not suitable; whereas, for panel 4 a percentage of COR equal to about 30% allows minimum \(\lambda\) and CED values, as observed above. Nothing changes also for the analysis of panel 5, that has the best mixture for 58% of Cork, 21% of Rice Husk and 21% of Coffee Chaff. Finally, for panel 6 the best solution is the one that has been investigated (40% of COR, 20% of RH, 20% of CC, and 20% of ELT), with \(\lambda\) of 0.071 W/mK and CED of about 43 MJ/m\({}^{2}\).  
Figure 4: Cross-comparative analysis of the panels in terms of thermal conductivity and GWP for 1 m\({}^{2}\) of panel: (**a**) panel 1; (**b**) panel 2; (**c**) panel 3; (**d**) panel 4; (**e**) panel 5; (**f**) panel 6.  
The presented analysis could be very useful for a careful optimization of the possible mixture of building components, such as insulating composed panels, taking into account different points of view.