Cooling and Energy-Saving Performance of Different Green Wall Design: A Simulation Study of a Block

Bohong Zheng,Yanfen Xiang,Jiayu Li,Zhiyong Qi,Wenquan Shen,Xiao Chen

doi:10.3390/en12152912

Abstract

To mitigate the urban heat island (UHI) and release the low carbon potential of green walls, we analyzed the cooling and energy-saving performance of different green wall designs. Envi-met was applied as the main simulation tool, and a pedestrian street named Yuhou Street was selected as the study object. Four designs of walls were summarized and simulated, demonstrating the living wall system (LWS). Super soil had superiority in cooling and energy saving. Outdoor air temperature, indoor air temperature, outside wall surface temperature, and inside wall surface temperature were analyzed. Apart from the outdoor air temperature, the other three temperatures were all significantly affected by the design of green walls. Finally, energy savings in building cavities were determined. The indoor energy saving ratio of the LWS based on super soil reached 19.92%, followed by the LWS based on boxes at 15.37%, and green facades wall at 6.29%. The indoor cooling powers on this typical day showed that the cooling power of the LWS based on super soil was 8267.32 W, followed by the LWS based on boxes at 6381.57 W, and green facades wall at 2610.08 W. The results revealed the difference in cooling and energy-saving performance of different green walls in this typical hot summer area.

Highlights

With the advancement of urbanization, many natural areas have become steel forests, bringing a series of problems, such as urban pollution and the urban heat island (UHI) [1,2]
The indoor energy saving ratio of the living wall system (LWS) based on super soil reached 19.92%, followed by the LWS based on boxes at 15.37%, and green facades wall at 6.29%
The indoor cooling powers on this typical day showed that the cooling power of the LWS based on super soil was 8267.32 W, followed by the LWS based on boxes at 6381.57 W, and green facades wall at 2610.08 W

Summary

Introduction

With the advancement of urbanization, many natural areas have become steel forests, bringing a series of problems, such as urban pollution and the urban heat island (UHI) [1,2]. The area of the building envelope, the facades, is much larger than that of the urban land surface, especially in high-density cities [10,11], which has a large impact on the thermal environment of cities and energy consumption of buildings [12]. Facade greening is a potential alternative measure for cooling the city and saving building energy consumption [13]. The most common places which can accommodate vegetation are the roof, vertical walls, terrace, and indoor space, especially in the high-density cities [15]. The wall area of buildings is larger than that of the roof [16], which hints at the importance of GW systems,

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Results

Conclusion