Vertical greenery systems for energy savings in buildings: a comparative study between green walls and green facades

Abstract

During the last decade, vertical greenery systems are increasing their presence in building designs, providing several urban ecosystem services. One of them is the potential to provide energy savings in buildings, which develops an important role, however, data about its performance during winter periods is still scarce. Therefore, the main objective of this paper is to compare at real scale the thermal performance of two different vertical greenery systems implemented in experimental houses-like cubicles for both cooling and heating periods. A double-skin green facade has been installed in the first cubicle that uses deciduous creeper plants, while the second one is designed with green walls made with evergreen species. Finally, a third identical cubicle without any green coverage is used as reference. Two different types of experiments have been carried out to test the performance of the house like-cubicles. One consists of controlling the internal ambient temperature providing heating or cooling to maintain the desired comfort conditions. On the other hand, to study the thermal response of the construction system, the heating, ventilation and air conditioning system was disconnected and the cubicles were tested under free floating condition. First results showed a high potential for energy savings during cooling season for green wall (58.9%) and double-skin green facade (33.8%) in comparison to the reference system. On the other hand, for heating periods no extra energy consumption was observed for evergreen system.

The work partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER), ENE2015-64117-C5-3-R (MINECO/FEDER) and ULLE10-4E-1305) in collaboration with the company Buresinnova S.A (C/Saragossa, 95 Entsol 3a, 08006 BARCELONA). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123) and to the city hall of Puigverd de Lleida. This study has received funding from the European Commission Seventh Framework Programme (FP/2007–2013) under Grant agreement Nº PIRSES-GA-2013-610692 (INNOSTORAGE) and from European Union's Horizon 2020 research and innovation programme under grant agreement Nº 657466 (INPATH-TES). Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940. Julià Coma would like to thank the Departament d'Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for his research fellowship.