Civil Engineering Reference
In-Depth Information
climatic and local controllers. Therefore, in order to evaluate the improvement in
the energy performance and the energy class which can be reached, some simu-
lations have been arranged for case A and B. In particular, UNI/TS 11300 Part 2
defines two kinds of assessment method for the generation subsystem efficiency:
• a simplified procedure, by using pre-calculated values for the generator effi-
ciency for the most common type of generators (Table 23—UNI/TS 11300
Part 2);
• two analytical procedures (B1 and B2 method) as reported in the Appendix B of
the Standard.
In particular, if the generator typology and the operational conditions corre-
spond to the standard ones reported in Table 23—UNI/TS 11300 Part 2, the first
possibility (use of listed values) is allowed. On the contrary, B2 method (analyt-
ical) and B1 method (based on efficiencies determined by virtue of 92/42/CEE
Directive) describe actual operational conditions.
It should be noted that choosing among different methods for generator effi-
ciency calculation can involve significant gaps in energy performance indicators
for the heating season; in particular, the listed values of the simplified method
generally overestimate generation losses.
Table
7
shows the results for case A, by using these three different assessment
methods: Table 23, B1 method and B2 method. Applying B2 method of UNI/TS
11300 Part 2 brings to the worst energy performance for heating with a gap of
32.6 % in comparison to B1 method.
Considering all the simulations, the boiler substitution does not improve the
energy label of the house, even if it brings to a reduction in EP
gl
that accounts for
32.5 % in comparison with the performance of the existing building.
In Table
7
, the corresponding results for case B are reported, showing that the
application of B2 method of UNI/TS 11300 Part 2 brings to the worst energy
performance in the heating season with a gap of 9 % with respect to simplified and
B1 methods which bring to approximately the same result.
As in case A, the energy label does not change, but the energy saving obtained
with the substitution of the generator accounts for 12.3 %.
7.6 Distribution Losses
UNI/TS 11300 Part 2 provides that the distribution losses can be evaluated by
doing the following:
• using pre-calculated efficiencies as reported in a table of the Technical Speci-
fication, distinguishing among the distribution typologies;
• applying the analytical method described in Appendix A of the National
Standard.
