b'(A) (A)(B)(B)FIGURE 5TEMPERATURE PROFILES OF ROOF SHEATHING BOARDS OF GR, RES AND EPS IN (A) SUMMER AND (B) WINTER, AND THE CORRESPONDING OUTDOOR AIR TEMPERATURE (TO).Figure 6 shows the heat flux sensor measurements on theFIGURE 6HEAT FLUX THROUGH GR, EPS AND RES IN (A) SUMMER interior side of the roof assembly. During sunny hours inAND (B) WINTER, AND THE CORRESPONDING OUTDOOR AIR summer, Figure 6(a), higher heat gain is observed for all greenTEMPERATURE (TO) AND SOLAR RADIATION (SOL).roof systems during late afternoon through the night due to the growing media thermal mass and plants insulatingloss through GR is 2.02 W/m2, and GR and EPS lowered effect, reducing airflow and convective heat transfer from thethe heat loss by 17.2 per cent and 36.7 per cent, respectively. roof, and the leaves shading of the roof from longwave heatFor the climate and the green roof configurations studied, exchange with the surrounding air at nighttime. In winter,the green roof with EPS drainage yielded a better energy the EPS shows the lowest heat loss followed by RES and GR,performance, but the higher growing media temperature and Figure 6(b). The EPS insulation contributes to heat gain/lossthe subsequent drier growing media may be a concern for the reduction compared to RES and GR; however, the reductionplant health during the summer months.is low if one considers conventional three-inch insulation, and the reason can be due to air convection loops, holes and groves in the EPS.Figure 7 shows the monthly average heat flux through GR, EPS and RES during measurement period. During cooling months, June to August, the heat gains through GR, RES, and EPS are comparable. The highest heat gain through the test building occurs in August, and the monthly average heat gains through the GR, RES and EPS are 0.28 W/m2, 0.29 W/m2, 0.27 W/m2, respectively. During heating months, October to April, the heat losses through the RES and EPS are 11.3-per-cent and 35-per-cent lower than GR, respec-tively. The highest monthly average heat loss through the testFIGURE 7. MONTHLY AVERAGE HEAT FLUX THROUGH GR, EPS, building occurs in December, and the monthly average heatAND RES DURING MEASUREMENT PERIOD.FALL/WINTER 2024 19'