In Fig. 8, the global warming potential results are presented for
the diffusers Scenarios 0–3. As can be seen, with different diffuser
designs that reduce electricity consumption during the compressor
use, the global warming potential of the studied system is decreasing.
The greatest savings in energy consumption and thus in greenhouse
gas emissions result from Scenario 3, where the vaned
diffuser is used. This saving is nearly 5% of the total GHG emissions
of Scenario 0 where the baseline, the vaneless diffuser, is used. In a
larger context, the 9.6 t CO2-eq. saving is also equivalent to the
average annual greenhouse gas emissions per capita in the EU-15
countries in 2010 [7].
Table 3 presents the global warming potentials of different scenarios
divided into manufacturing the diffuser out of aluminum
and the use of the compressor in a wastewater treatment facility
during one year. It can be seen that even if the amount of
aluminum is increased in Scenarios 1–3 compared to the baseline
diffuser, its share of the total global warming potential is minimal.