ENERGY EFFICIENCY OF GREEN ROOFS AND GREEN FACADES IN.pdfVIP

ENERGY EFFICIENCY OF GREEN ROOFS AND GREEN FACADES IN MEDITERRANEAN CONTINENTAL CLIMATE Gabriel Pérez1, Lídia Rincón1, Anna Vila1, Josep M. González2, Luisa F. Cabeza1 1 GREA Innovació Concurrent Edifici CREA, Universitat de Lleida, Pere de Cabrera s/n, 25001-Lleida (Spain) Phone: +34-973 003576, Fax: +34-973 003575 e-mail: lcabeza@diei.udl.cat 2 Dept. Construccions Arquitectòniques I, Universitat Politècnica de Catalunya Avinguda Diagonal 649, 3a planta, 08028-Barcelona (Spain) ABSTRACT There are now many studies concerning the benefits of green roofs and green facades as passive systems in the energy efficiency of buildings. These benefits depend largely on the ability of plants to intercept solar radiation, and therefore their growth. On the other hand, the standard design of these systems makes difficult their implementation in these extreme conditions, and it is imperative to obtain data of their behaviour under local conditions. Moreover, some authors consider the use of green roofs and green facades as a thermal storage technology for buildings. These are the reasons why the research group GREA has initiated an investigation near the city of Lleida (Spain), to evaluate experimentally the energy impact of using green roof systems and/or green facades in Mediterranean-continental conditions. This paper presents a state of the art of the energy impact of these systems over the world and the first experimental results. 1. INTRODUCTION In recent years the benefits of green roofs as passive systems for energy saving in buildings have been studied in depth. They are basically three fundamental mechanisms, the interception of solar radiation by means of the shadow produced by the vegetation, the evaporative cooling that occurs by evapotranspiration from the plants and the substrate, and finally the thermal insulation provided by vegetation and substrate. However, there are few studies on the use of green facades as a passive system f