DOI: 10.7569/JRM.2017.634135
M.Cˇ ekon et al.: Cardboard-Based Packaging Materials as Renewable Thermal Insulation of Buildings
total normalized environmental impacts of any other assessed material. The environmental impacts of MW are worse than CBMs M1 to M6. Only the environmental impacts of sample M7 are 54% higher than those of MW. The reason why MW has higher environmental impacts than six out of seven tested CBMs lies in the combina- tion of its relatively high density and environmental impacts per 1 kg. Table 4 and the accompanying text in Section 4.2 have already explained the small difference between the compared mass of MW and CBMs. This is combined with the fact that environmental impacts of the production of MW are twice as high as environ- mental impacts of the production of CBM (see Tables 5 and 6). The resulting comparison is a fine example of the necessity of complex multi-criteria evaluations: it proves that even if a material has worse physical properties, it can still be potentially better than others overall. EPS has lower environmental impacts than any assessed CBM. The difference varies between 12% (in the case of HFB M6) and 63% (in the case of CFB M7). CBMs have lower environmental impacts per 1 kg than EPS (see Tables 5 or 6). However, the EPS has higher thermal resistance and lower density than any assessed CBM sample. Therefore, the compared masses of EPS and CBMs differ greatly, which favors the EPS overall. The obtained results correspond with the findings of Asdrubali et al. [9]. The results of their LCA also show that the CBMs have environmental impacts sim- ilar to EPS and MW. 5 CONCLUSION This paper introduces a potential novel thermal insulation material for buildings—CBM. In general, the results show that when compared by thickness the thermal properties of the CBMs are almost two times worse than those of more common insulation materials. Depending on their internal structure, the measured thermal conductivity varies from 0.05 to 0.12 W·m –1 ·K –1 . This basically corresponds to the results achieved by Asdrubali et al. [8], who measured the thermal conductivity of cardboard-based panels to be around 0.055 W·m –1 ·K –1 . However, there is further potential for improvement. The results show that ther- mal properties of CBMs are directly dependent on the size and shape of air cavities enclosed in the CBMs’ structure. Modifications of these air cavities could improve the thermal properties of CBM to levels com- parable with common thermal insulation materials. Based on this study we can say that CFBs appear to
POCP
1.2E – 11
1.0E – 11
ODP
8.0E – 12
GWP
6.0E – 12
EP
4.0E – 12
AP
2.0E – 12
ADP fos.
0.0E + 00
ADP el.
Figure 11 Total normalized environmental impacts related to production of cardboard M7 and equivalent mass of PIR, EPS and MW.
individual impact categories on the normalized environmental impacts is highlighted by different colors. We can see that the consumption of natural resources represented by ADP-el. (excluding fossil fuels) has the highest share of the results in the case of PIR (48%), MW (32%) and CBMs (32%). The only exception is EPS (13%), which is probably due to its very low density and thus low consumption of raw materials. The second most important category in regard to its share on total results is the POCP. It has a 73% share on normalized environmental impacts of EPS and 26% to 22% share on environmental impacts of PIR, MW and CBMs. The environmental impacts in these two categories alone represent 75% (EPS), 74% (PIR), 57% (CBMs) and 55% (MW) of total normalized environmental impacts of the assessed materials. 4.4 LCA Discussion The results of individual LCAs in Figures 5 to 11 show that environmental impacts related to the production of the CBMs are comparable with envi- ronmental impacts of other common insulation materials. The worst environmental impacts in all seven LCAs are related to PIR insulation. It has environ- mental impacts that are three (compared with M7) to eight (compared with M6) times higher than the tested CBMs. This is due to the very demanding pro- duction process of the PIR (see the normalized envi- ronmental impacts related to ADP-el.). This category represents the consumption of resources (excluding fuels). Environmental impacts related to the produc- tion of PIR in this category alone are higher than the
J. Renew. Mater. Supplement June 2017
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