The VISUAL DOE 4.0 energy simulation programwas used in this
study to determine the energy consumption of the experimental model. For the steady state condition, the rate of heat flow per unit
area through the element of the building was estimated as
Q ¼ ð1=ErÞDt (1)
where Q (W/m2) is the rate of heat flow per unit area through
compound elements as in Fig. 4. Er or R (m2 K/W) is the total
resistance of compound elements shown in Table 1. Dt (C) is the
surface temperature difference.
For this treatment, surface temperatures at different points of
each treatment were recorded for the calculation of equivalent
U-values of treatment with grass. These U-values were used in the
VISUAL DOE 4.0 energy simulation program (Table 2).