Civil Engineering Reference
In-Depth Information
110
1-STANDARD GLAZING
OLD BUILDING
2-STANDARD GLAZING
3-LOW-E
4-GRANULAR AEROGEL
5-GRANULAR AEROGEL
6-MONOLITHIC AEROGEL
7-TRIPLE GLAZING
105
100
95
90
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
BEIJING TOTAL
HELSINKI
TOTAL
LONDON TOTAL
MOSCOW
TOTAL
OTTAWA TOTAL
ROME TOTAL
Fig. 23 South exposure: annual energy demand for conditioned building area for the six cities
and for seven different kinds of glazing
perform very well. The best solutions for the annual energy demand reduction are
the granular aerogel glazing systems: the annual energy demand reduction varies
in 10-20 % range with regard to the standard glazing (type 2).
6 General Conclusions and Future Trends
Nowadays, translucent or transparent aerogel glazings have a high potential in
fenestration market, due to low U-values (down to 0.1 W/m
2
K, depending on
thickness and technology) together with very interesting properties such as thermal
and acoustic insulation, light transmission, and finally lightness. Alternative high-
performance solutions, such as vacuum insulation panels (VIP), have technical
limits (problem of keeping the glazing gas-tight) and very high costs.
As shown in the case study presented in this chapter, glazings with monolithic
aerogel in interspace are the most efficient systems for very cold climates: for
instance, in Ottawa the annual energy demand decreases about 22-27 % when
compared to the standard glazings. Nevertheless, due to the high solar factor (g), the
energy demand for cooling increases for monolithic aerogel windows, especially in
temperate climates. Therefore, in general, granular aerogel glazing systems could
be considered the best solutions in terms of annual energy demand reduction.
In relation to monolithic aerogel systems, in the future, the research should solve
some relevant problems: the phenomenon of light scattering, which gives a reduced
