Numerical-experimental study of the thermal behavior of a green facade in a warm climate in Mexico

• Published in: Energy and buildings 2024-05, Vol.311, p.114156, Article 114156
• Main Authors: Báez-García, W.G., Simá, E., Chagolla-Aranda, M.A., Carlos Sandoval Herazo, Luis, Carreto-Hernandez, L.G.
• Format: Article
• Language: English
• Subjects: Buildings; Energy; Experimental study; Green facade; Numerical study
• ISSN: 0378-7788
• DOI: 10.1016/j.enbuild.2024.114156

Demographic growth entails an increase in the construction of buildings and streets, whose materials significantly absorb heat and, upon release, create discomfort for the inhabitants of large urban areas. Vegetation emerges as a crucial element to enhance both the indoor environment of buildings and the outdoor surroundings. Green facades present themselves as a highly efficient alternative to integrate vegetation in densely urbanized areas. This study focuses on evaluating the thermal performance of an indirect-type green facade system in a warm climate in Mexico. The research encompasses experimental measurements and numerical simulations of the thermal effect of the green facade and also a parametric study of the vertical leaf area index (LAIV) and air gap size. In the experimental test, temperatures were recorded in two identical test cells, one of which was equipped with a green facade with Pyrostegia Venusta plants on one of its surfaces. The numerical study validated the results obtained through experimental tests, using simulations of Computational Fluid Dynamics (CFD) considering a typical day for each season throughout the year. Validation results revealed Mean Percentage Errors (MPE) of −2.86 % and 0.25 %, Mean Bias Errors (MBE) of −0.49 °C and 0.08 °C, and Root Mean Square Errors (RMSE) of 1.34 °C and 1.29 °C for the bare facade and the green facade, respectively. In the numerical analysis, it was observed that the green facade succeeded in reducing the indoor air temperature in a range of 4.57 to 5.64 °C, while decreasing the heat flux in an interval of 7.84 to 16.79 W/m2. Moreover, a parametric study revealed that the LAIV ceases to be a significant parameter beyond 2.5, while the air gap size proves to be a considerably less influential factor compared to the LAIV. These results confirm the relevance of using vegetation in buildings to mitigate the effects of heat and improve the thermal comfort of inhabitants.