Net ZEB Case Studies - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 404

Table 7.11 LH energy balance (2009) - Redesign 2-7 combined

LH energy balance [MWh] −29.09
LH energy balance [%] −28.41

Consumption [MWh] 102.38

Production [MWh] 73.29

Table 7.12 LH energy balance (average values 2010-2011) Redesign 2-7
combined

LH energy balance [MWh] 5.45
LH energy balance [%] 7.86

Consumption [MWh] 69.30

Production [MWh] 74.75

If the first scenario is also considered, the balance would be far over the
net-zero energy point, as summarized in Table 7.13 .

Table 7.13 Redesign - all options combined

LH primary energy balance [MWh] 42.59
LH primary energy balance [%] 61.45

Consumption [MWh] 69.30

Production [MWh] 111.89

In order to strengthen the reliability of the model and evaluate variations in
theGHPheatingconsumption,asensitivityanalysisondifferentparameters
was carried out. The variation of PID setpoint temperatures, air infiltration,
tank setpoint temperature, and occupancy level was taken into account.
The PID setpoint temperatures were set between 20 and 23 °C, numerical
values of infiltration were varied from 50 to 150% of the initial value, and
the tank setpoint temperature was fixed in the range of 35-45 °C while the
occupancy level was set up to 0-5 people. The highest variation of the GHP
consumption is related to the PID setup temperature sensitivity (nearly
+40%), the lowest is connected to the occupancy level variation (+/−10%).
The sensitivity analysis has proven that the choice of values for user-defined
parameters can have a major impact on the results of the simulations and
on the reliability of the model. Other parameters evaluated are maximum/