Practical Study on the Effect of the Plants on the Roof of a Building to Reduce the Heat Absorption of the Building and the Urban Area

Abstract

A measurement experiments were done in order to examine the effect of planting on the roof of a building to suppress the increase of surface temperature in summer of 1993. The data of thermal environment such as temperature, heat flux, etc. were continuously measured by machine at 3 typical points (the area planted with shrubs, the pavement within shade of a table and the pavement without shade). Also other data such as leaf transpiration rate etc. were measured by man power on the cloudy day of August2 and the fine day of August 12. At the pavement without shade, the surface temperature (maximum56.6°C) and the heat flux from outside toward the roof of the building (maximum507W/m²) were the highest among3typical points. At the pavement with shade, the surface temperature was fairly law (maximum32.6°C), but the heat flux was still big (maximum 121W/m²). On the other hand, at the planted area, the temperature was lower than the shaded pavement except around14: 00and the heat flux was very small (maximum33W/m²) by the effect of cutting sun beam, and the transpiration from leaves.