Thermal performance of a hollow block with/without insulating and reflective materials for roofing in Mexico

The thermal analysis of a hollow block with/without insulation and reflective materials for roofing was studied during 24 h (hottest and coldest days) considering environmental variables from a city in Mexico with hot weather. The traditional blocks used for roofs in Mexico with two and three hollows were considered. The different configurations of roof analyzed are: (C1) Reference or traditional block (hollow block + concrete slab), (C2) Traditional block with a reflective coating on the outer of the slab (hollow block + concrete slab + reflective coating), (C3) Traditional block with an insulating material between the outer surface of the block and the slab (block hollow + insulation + concrete slab) and (C4) Traditional block with a insulation material and a with a reflective coating on the outer surface of the slab (hollow block + insulation + concrete slab + reflective coating). The different coatings considered are: Gray, Black and White. The results show that the configuration C4 with a white reflective coating demand a lower thermal load for the block with two hollows (B2-Wins-RW) and three hollows (B3-Wins-RW) with a value of 1045.3 and 975.9 W h/m2, respectively. These values represent a decrease in the thermal load of 32.4 and 46.3% with respect to the traditional roof (C1). This result shows the advantage of using the combination of insulating material and reflective coating on roofs with hot climates.