Net ZEB Case Studies - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 449

reduction in the peak cooling demand. Figure 7.71 shows the temperature
and illuminance profiles of different thermal zones, as well as the control
action for the VC, and the space cooling power requirement. The
temperature of the north thermal zone is slightly higher than that of the
south zone. This is because the north zone has higher overall solar heat gain
due to no solar control (e.g., in the early morning and late afternoon). Based
on model calibration, the infiltration rate of the north zone is 2.5 times
that of the south zone, which is 0.1 ACH based on the south thermal zone
volume. That means the north zone also has higher heat gain from exterior
hot air.
Fig. 7.71 With 30 ACH nighttime natural ventilation and exterior reflector
installed
Further potential enhancement in an archetype . The volume of concrete
in the ceiling slab of the typical section is about 5.7 m 3 . A 1 °C change
in the slab temperature results in 3.04 kWh of thermal energy storage.
Simulation shows that this amount of energy is able to reduce the peak
room temperature in free-floating mode (i.e., no space cooling provided)
and replace the energy spent on cooling supply outdoor air, which can also
be reduced by heat recovery ventilation. Additional temperature drop of
the slab can be achieved through increasing the thermal coupling between