Vertical Greenery and Albedo Enhance Urban Thermal Comfort
New research demonstrates that vertical greenery and specific exterior surface properties can significantly improve both indoor and outdoor thermal conditions in urban environments, particularly under extreme heat and power outage scenarios.
Urban heat island (UHI) effects are exacerbated by climate change and urbanization, leading to hotter cities, more frequent heatwaves, and increased energy demands for cooling. Previous mitigation efforts have often focused on outdoor environments, but the dynamic interaction between indoor and outdoor thermal conditions through building envelopes necessitates an integrated approach. Furthermore, the resilience of buildings during compounded extreme events like heat waves coinciding with power outages has been under-examined.
An international research team, led by Associate Professor Jihui Yuan at Osaka Metropolitan University, investigated the impact of UHI mitigation strategies (UHIMS) on both indoor and outdoor thermal environments. Their study, conducted on an educational facility in the hot climate of Shahrud, Iran, utilized an integrated simulation method. This approach combined a Building Energy Model (BEM) for indoor conditions with an Urban Microclimate Model (UMM) for outdoor dynamics.
The simulations incorporated future climate scenarios and extreme conditions, including summer heat waves and power outages, to assess building performance realistically. Thermal comfort was evaluated using the Physiologically Equivalent Temperature (PET) for consistent indoor and outdoor comparisons. The findings revealed that a green wall on the south-facing facade improved indoor thermal conditions by up to 1.7°C.
Additionally, the study highlighted the significant role of albedo, the measure of surface reflectivity. Low-albedo exterior surfaces enhanced outdoor thermal comfort by approximately 1.5°C. Conversely, high-albedo exterior surfaces proved more effective in reducing indoor temperatures. The research also determined that the radiative properties of exterior materials exert a stronger influence on thermal environments than their heat capacity.
This study's integration of building-scale and urban-scale simulations, including extreme conditions, offers a novel approach to UHI mitigation. The findings on vertical greenery and albedo's impact on both indoor and outdoor temperatures are crucial for developing resilient urban infrastructure and buildings. This research contributes to the broader push for sustainable and energy-efficient additive manufacturing applications in construction and materials science for climate adaptation.
Edited by the news editor with AI from the original report — please refer to the original source.