Vegetation growth parameters and leaf temperature: Experimental results from a six plots green roofs' system. (15th November 2016) - Ferrante, Patrizia
Abstract: The paper provides a contribution for populating database of three physical parameters needed to model energy performance of buildings with green roofs: "coverage ratio" ( σ f ), leaf area index (LAI) and leaf temperature ( T f ). On purpose, six plant species were investigated experimentally: Phyla nordiflora, Aptenia lancifolia, Mesembryanthenum barbatus, Gazania nivea, Gazania uniflora, and Sedum . Proper ranges of the cited parameters have been found for each species. The here indicated ranges of σ f values refer to different growth levels of the species in the same lapse of time, that is four months. Single measured LAI values are also reported for the same plants. As for the T f (upper and lower layer), ranges of revealed temperatures refer to those detected from 10:30 a.m. to 16:30 p.m. of a selected day. Additionally, the dependence of T f on climatic parameters was investigated. A linear equation resulted the best fitting curve for all experimental T f data and the corresponding solar radiation data (with autocorrelation coefficients between 0.80 and 0.98). Furthermore, the effect potentially produced on building energy consumption by these species was analyzed using a simulation tool. Estimated cooling energy savings range approximately between 8% and 20% depending on adopted plants. Highlights: Green roof modeling requires the knowledge of various physical parameters. Coverage ratio, leaf area index and leaves temperatures were measured for six species. A tentative correlation between leaf temperature and climatic parameters was shown. A correlation between LAI and coverage ratio was checked and discussed. Potential effects of studied species on building energy consumption were investigated.