Page 89 - New Trends in Green Construction

ENERGY SAVING POTENTIAL OF GREEN ROOFS IN SOUTH EUROPEAN CLIMATES
M. Porcaro, M. Ruiz de Adana, F. Comino, A. Peña, E. Martín Consuegra,T. Vanwalleghem
1
Keywords: extensive green roofs; recycles substrates; energy saving 1. Introduction
Greenroofsarepassiveconstructionsystemsthatallowtoreducethethermalloadsofabuilding and decrease the temperature fluctuations of the roof assembly (Li, 2013). Green roofs also help to mitigate the urban heat island effect through evapotranspiration process, absorb CO2 and retain meteoric water (Shafique, 2018). This work focuses on the study of extensive green roofs, whichhaveathicknessof60-200mmandtheplantspeciesusedrequirelowmaintenance (Besir, 2018).
The main objective of this study was to obtain experimentally the energy saving of three extensive green roofs with different substrates, compared to a traditional gravel ballasted roof, during the summer period, for the climatic conditions of Córdoba.
2. Materials and methods
The three plots with green roofs and a reference plot with gravel ballasted roof were installed in an office building located in the University of Córdoba. The substrates of the three green roofs were composed of commercial growing medium and recycled construction materials, each of them with a different percentage, see Figure 1. In each green roof, ten temperature probes were installed along the vertical profile of the parcel, five in the east side and five in the west side. Two heat flux probes and two water content probes were also installed, one in the middle of each side, see Figure 1. In the reference plot three temperature probes were installed in the middle of the parcel, along the vertical profile, and two heat flux probes, see Figure 1.
Figure 1. Plots layers and sensors of the green roofs and the reference plot.
Experimental data of heat flux were collected during the summer period of 2016, from June to
September. The energy saving of each plot was calculated with Eq. 1, where q' is the heat flux [W/m2] referred to the area of the parcel [m2].
New Trends in Green Construction
89