Thermal influence of living wall in the winter of subtropical climate in Brazil

Abstract

The continuous living wall is a type of vertical garden built with different layers, which allows the cultivation of a wide variety of species and protects the façade from direct sunlight. From this, this experimental study aimed to identify and quantify the influence of a continuous living wall on the variations of the internal and external surface temperatures (Ist and Est) of an East façade, in the winter period, in the Cfa climate. The garden had the differential of being built with Tetrapak® recycled boards to differentiate it from the other technologies already studied and to test a material used in environmental compensation projects. The surface temperatures of the living wall, the protected and the control plot were monitored and compared to analyze the intensity of the shading mechanism. The results demonstrate that, in the early morning, the living wall prevented heat loss from the façade and, from direct sunlight, kept the protected plot's surface temperatures lower than the control plot. This difference reached up to 9.4 °C at Est (morning period) and 2.8 °C at Ist (afternoon period), as well as a maximum thermal delay of 06h30min between Est peaks. These findings show the positive influence of the living wall in winter, considering the characteristics of the Cfa climate (cold in the morning and hot during the day), expand knowledge about the thermal influence of the continuous living wall in the building and reinforce the use of living walls beyond aesthetics.