Sustainable Building Operation Using Simulation - Low Energy Cooling for Sustainable Buildings - page 208

Figure 6.6 Daily cooling loads of a small office building with the main window front facing east, south
or west
To evaluate the influence of the specific time series of the building cooling load,
two cases were simulated:
Case 1: Cooling load dominated by external loads through solar irradiance for un-
shaded windows and low internal loads of 4Wm − 2 (see Figure 6.7).
Case 2: Cooling load dominated by internal loads of 20Wm − 2 with good sun
protection of all windows (see Figure 6.9 and Table 6.2).
In addition, Case 1a is an office building with the same geometry, but the main
window front is to the east instead of south. Case 1b has nearly 40% of the windows
facing west. The peak values of the daily cooling loads are highest for the office with
a western window front and lowest for the eastern offices. The phase shift between
the curves is about one hour (see Figure 6.6).
The cooling load file with high internal loads shows less daily fluctuations and is
dominated by the external temperature conditions. For the office building, the load is
between 12 and 14MWh for low internal loads up to 30MWh for the same building, but
higher internal loads. The same building at a different geographical location (Stuttgart
in Germany instead of Madrid in Spain) has a cooling energy demand of only 4.7MWh
(Figures 6.7 and 6.8). A wide range of specific cooling energies is covered, ranging
from about 10 kWh m − 2 for an office with low internal loads in a moderate climate up
to 70 kWhm − 2 for the same building in Madrid (Figure 6.9) and high internal loads
(see Figure 6.10).
The specifications for the buildings with the different cases are summarized in
Tables 6.1 and 6.2.