Inter-building assessment of urban heat island mitigation strategies: Field tests and numerical modelling in a simplified-geometry experimental set-up

Abstract

Large scale mitigation strategies showed to represent promising solutions for enhancing liveability in dense urban contexts. Therefore, most of the researches are focused on assessing the effect of high albedo surfaces and greenery. The paper deals with a numerical and experimental analysis of these evapotranspiration and high-reflectance surfaces in a full scale experimental set-up where more than 20 cubicles are monitored in a Mediterranean continental climate. The experimental set-up itself covers an intermediate inter-building perspective between the lab scale and the real urban contexts, which compromises the possibility to generalize final results. This scale is able to better control geometry of area, but allows real microclimate monitoring and calibration of CFD models. Starting from a validated model, this study simulated alternative scenarios with gradually varying the presence of common mitigation strategies with the scope to evaluate their effect to this aim. Results showed that high albedo solutions best mitigate summer overheating reducing the air temperature, while greenery was more effective in the densest configurations with low albedo envelopes, showing how geometry related variables may play a key role in determining the optima configurations of microclimate mitigation strategies, also important for the best exploitation of renewables in the built environment.

The work is partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER) and ULLE10-4E-1305) and SOS CITTA’ (Fondazione Cassa di Risparmio di Perugia, (2018.0499.026). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537) and the city hall of Puigverd de Lleida. GREiA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. Marta Chàfer would like to thank the program Spanish Universities for EU Projects from Campus Iberus for the mobility scholarship. Ilaria Pigliautile would like to acknowledge the PhD Course of Energy and Sustainable development at University of Perugia and H2CU centre for supporting her international activities and scientific collaborations during the course of her PhD. The authors from University of Perugia also thank UNESCO Chair on “Water Resources Management and Culture”, and the Honors Centre of Italian Universities (H2CU) for supporting their studies on wellbeing.