屋上緑化建築における屋根面蒸発散量とCO₂削減効果の数値シミュレーション

抄録

This research evaluates evapotranspiration from rooftop vegetation and its effects of urban heat island mitigation and CO₂ reduction in office building areas. First we conducted urban microclimate and air conditioning load simulation by using a coupled urban-canopy and building energy model (CM-BEM).Next, we calculated evapotranspiration on rooftops from latent heat flux derived from surface heat balance simulated by CM-BEM. From calculated evapotranspiration result, we determined required water volume and CO₂ emissions for sprinkling water. Then, we quantified the CO₂ reduction effects of rooftop greening by comparing the CO₂ emissions for sprinkling water and the CO₂ reduction by cooling energy savings calculated from air-conditioning load simulation. Finally, we evaluated the relationships between evapotranspiration and urban heat island mitigation effects and CO₂ reduction effects.