Experimental Assessment of the Thermal Influence of a Continuous Living Wall in a Subtropical Climate in Brazil

Abstract

A continuous living wall is a vertical garden that allows the cultivation of a wide variety of species on vertical surfaces, consisting of a sequence of layers that shade and add thermal resistance to the external façades of buildings. Thus, the living wall can be an alternative to increase the thermal efficiency of the building and reduce the use of air conditioning for cooling the indoor environment. This work experimentally investigated the thermal influence of a continuous living wall on the surface temperatures of an east façade in a subtropical climate with hot summers (Cfa), during the summer period. The experiment included the implementation of a real living wall in a seasonally used building and the delimitation of two sample plots (i.e., protected and bare wall). Campaigns were carried out to measure the external and internal surface temperatures of the protected plot, the living wall, and the bare wall, as well as the cavity air temperature, from 08:00 to 17:45, at 15-min intervals. The results show the efficiency of the living wall in reducing the external (up to 10.6 °C) and internal (up to 2.9 °C) surface temperatures of the protected plot compared to the bare wall, along with a reduction in thermal variation (average reduction of 6.5 °C externally and 3.6 °C internally) and an increase in thermal delay (up to 6 h for external and 1 h for internal), in addition to a reduction in temperature and greater thermal stability of the cavity between the garden and the protected land in comparison to the external space.