Environmental Engineering Reference
In-Depth Information
Figure 2.18 Schematic representation of the simulated office room
package Thermplan corresponds nearly exactly to the TRNSYS results. The newmodel
(type 111) gives a higher cooling energy demand than the standard fa¸ade model (in
type 56), which is mainly due to neglecting the angle-dependent reflection losses. As
expected, the energy use for heating is reduced by increasing the window area due to
the solar gains. The energy use for heating and cooling reaches an optimum for this
office situation for a window area percentage of about 25%. This confirms the impor-
tance of low window fractions to maintain low cooling loads in office buildings. The
single fa¸ade can now be compared with a double fa¸ade with and without sun shading
elements. In all of the cases, a constant infiltration rate of 0.7 h 1 was assumed. The
external heat transfer coefficient was set to a more realistic value of 10Wm 2 K 1 ,
Figure 2.19 Heating and cooling energy demand as a function of window fraction calculated with
dynamic and monthly energy balance simulation tools
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