Nocturnal radiation

Even in relatively warm area in Japan, frost damage of roof tiles occurs. In this study, the influences of several factors on frost damage are considered from a thermal environmental point of view. Condensation on the external surfaces of roof tiles, which is caused by a temperature drop due to nocturnal radiation, is estimated as one of the most important factors to the frost damage. The frequency of condensation was calculated by a numerical analysis. The influence of the parameters, such as the inclination angle and the orientation of the roof, is investigated.

Even in relatively warm areas in Japan, frost damage of roof tiles occurs. In the field of material scienceand technology, the mechanism of frost damage has been investigated. In this study, frost damage toroof tiles is considered from a thermal point of view. A temperature drop due to nocturnal radiation isestimated as one of the most important factors. The influences on the temperature profiles areexamined by numerical analysis. Next, an accelerated aging test for roof tiles and a numerical analysisof the test are carried out.