Urban Overheating Mitigation Strategies Opportunities: A Case Study of a Square in Rome (Italy)

Abstract

It is well-known that the occurrence of urban heat islands (UHI) is related to climate change and urbanization. Urban locations experience local overheating throughout the summer, which is uncomfortable and it has a detrimental impact on buildings ability to consume energy. In this study, a methodology was developed to assess the urban heat island effect in a localized urban area and to evaluate the effects of different kind of mitigation strategies. The numerical model was developed using the ENVI_met tool and it was calibrated with weather data and albedo measured inside the examined area and near the simulated domain. The procedure adopted overtaking the limit of the software in reproducing accurate weather conditions without calibration. Finally, combination of extensive mitigation strategies (cool pavements, greenery, grass pavers) with local strategies (shading) were investigated. An experimental and numerical investigation of a square in Rome was exanimated to evaluate the possible solution for mitigating outdoor air temperatures. Results of the paper affirm that an intervention on the pavement albedo and the increase of vegetation inside the square, lead to an improvement of the air thermal conditions. In particular, the application of the grass pavers would lead to the greatest benefits. A maximum decrease in the air temperature of 1.2 °C was obtained through the application of cool material, while the reduction reaches up to 2.88 °C when a grass paver is applied. The improve of the vegetation can bring to a maximum decrease of 1.46 °C, while the use of shading projecting roof allows a reduction up to a maximum of 2.07 °C.

A Systematic Review of Outdoor Thermal Comfort Studies for the Urban (Re)Design of City Squares

“…These studies lack any CFD model assessment for scenario comparison or subjective thermal perception evaluation. Most studies are with microclimate data monitoring, CFD model scenario simulation with thermal comfort assessment for different mitigation strategies, and an evaluation of microclimatic improvements [15,18,81,82,84,[88][89][90][91]94,95,137,[153][154][155][156][157][158][159][160][161][162][163][164][165][166]. Developing and testing alternatives, such as the process "research by design", this research paper describes design outcome, evaluation, and design process-mitigation model or strategy.…”