Effects of Exterior Sunshades on Heat Transfer by Solar Radiation

摘要

Heat transfer in walls, as affected by climatic conditions such as fluctuations in outside air temperature, solar radiation intensity and wind speed as well as wall structures and heat transfer coefficients of materials, becomes a complex and non-steady state. The aim of this paper is to examine the relationship between total whole-day solar radiation and heat absorbed by and released from materials. An reduced scale of experiment was conducted using reduced scale precast concrete slabs and focusing on the effect of heat transfer involving solar radiation, building materials and shading rate. The results show that even though the sun shadings would stem partly the solar radiation into the wall, yet they obstruct in the mean time the release of the heat, which absorbed hours ago. That leads to a temperature raise and uncomfort to the interiors.