Research On Expanded Perlite Modules Evaporation Insulation Characteristic Analysis

Roof as the main roof building palisade structure, which has much more effect on indoor temperature and hot wet environment of the top-level, the phenomena of hot summer and cold winter are very obvious, so we should take more attention on roof heat preservation and heat insulation performance. The passive evaporation roof with the certain structural model has good insulation impact and environmental effect, but the current study on passive evaporative roof is mostly focused on the water pool roof and green roof, the research on the expanded perlite evaporative roof is relatively few.According to the climatic characteristics of the Guangzhou region, combine the research in domestic and foreign, a new structure experimental expanded perlite evaporation insulation platform were established Comparing the different modules passive evaporative heat insulation effects in sunny days and rainy days, Further research expanded perlite evaporation layer thickness impact on the insulation effect, And calculate the equivalent thermal resistance of the module in sunny days.The size of the experiment modules was1200mm x1200mm x150mm. Module structure from top to bottom in order as:geotextile、porous materials evaporation layer、 geotextile、storage drainage board.Insulation characteristic analysis:expanded perlite module show good insulation properties both in sunny days and rainy days. In sunny days, the module underside temperature is rising; In rainy days, the module underside temperature show downward trend. Expanded perlite module underside temperature in low temperature below30℃in sunny days and rainy days, temperature frequency were76%、87%, Temperature frequency were not in the high temperature zone. Expanded perlite module underside temperature relative to the outdoor air temperature、exposed roof temperature, which have a large temperature wave attenuation and delay. In sunny days, Expanded perlite module temperature amplitude of0.8℃、peak and valley difference1.5℃、attenuation ratio0.08、delay time420min; In rainy days, which temperature amplitude of1.2℃、peak and valley difference2.3℃、 attenuation ratio0.11、delay time240min.Analysis on the relationship between the expanded perlite evaporate layer thickness and the effect of the roof evaporative insulation, In this experiment six kinds of expanded perlite module with different thickness and same structure were established in the same roof. By analyzing the experiment data during the succession sunny days, the relationships between the different thickness for expanded perlite module and the differences at degree of decay and delay time of temperature are found and some conclusions are derived from the above analysis. Module3(5.22cm)on attenuation ratio and delay time of temperature are found performed better. which temperature amplitude and peak and valley difference are small,0.9℃、1.9℃;Take outdoor air temperature maximum appear time as the benchmark computing module underside temperature delay time, the longest delay time were module3and module6, delay time was260min. Though contrast:with the increase of the thermal insulation layer thickness, heat insulation temperature not present obvious linear change characteristics.Expanded perlite evaporation module equivalent thermal resistance, August15, average equivalent thermal resistance was2.1(m2-K)/W, August16, average equivalent thermal resistance was2.2(m2·K)/W, August17, average equivalent thermal resistance was2.2(m2·K)/W, three days average equivalent thermal resistance was2.2(m2·K)/W, thermal conductivity is0.045W/(m2·K), module has good evaporation insulation effect.