Development of tools for the proper prediction of urban cooling potential associated with the implementation of cool and green roofs: application to a case study

Abstract

In Mendoza city, Argentina, the intensive sealing of surfaces due to urban growth increases the temperatures of the outdoor air and the surfaces of the urban-building envelope. Mitigation strategies aim to restore the thermal balance of cities, favouring losses and decreasing profits. Internationally, the most efficient strategies are the application of cool and green roof. The objective of the investigation is to generate reliable predictive tools that describe the microclimatic changes of urban environments in an arid context. Methodologically, three stages were carried out: (1) Experimental test: evaluation of the thermal and optical performance of cool roofing materials of greater local application -aluminium and geotextile membranes- and vegetated roofs with greater hygro-thermal efficiency in the region with the species Nassella tenuissima and Sedum spectabile. (2) Databases: generation of input data of materials and technologies of roof for urban climate forecasting software, ENVI-met, adjusted to the regional arid environment through optical and thermal characterization. (3) ENVI-met theoretical models: comparison of the thermal behaviour of 4 scenarios that differ in their cover technology with respect to a base case. As a result, the high degree of adjustment of the air temperature of the daily curves measured in comparison with the simulated curves is observed, which supports the reliability of the predictive results of ENVI-met in relation to the urban thermal behaviour. As a final conclusion, the combination of variables as the selection of plant species used in green roofs in relation to the local climate resources and diverse roofing technologies would allow us to get different energy efficiencies at object, building and urban scale. The adjustment of prediction tools through simulation that link models at different scale such as Energy Plus and ENVI-met will facilitate both sustainable buildings design and urban planning.