Methodology for the use of aerial thermography as a validation method for outdoor thermal comfort simulations

Abstract

The urban heat island (UHI) effect underscores the importance of outdoor spaces in urban planning and design, where thermal comfort has become a critical consideration. Mean Radiant Temperature (MRT) is a dominant factor influencing human thermal perception, making its accurate simulation essential for creating comfortable urban environments. Despite the widespread use of simulation tools, a significant gap exists in their validation, particularly during early design stages. This study introduces a novel methodology for calibrating and validating longwave MRT simulations using aerial thermography, providing a practical and robust approach to improving simulation accuracy. As an example of the proposed methodology, a practical application is carried out using Ladybug Tools® (LBT), a widely used simulation tool known for its powerful features, open access, and integration with early-stage design workflows. It was used to simulate an open space located in Huelva, Spain, under summer conditions. The calibration process refines parameters such as albedo, shading, and grid resolution, ensuring results align with ASHRAE guidelines. The findings demonstrate that, after calibration, LBT can effectively predict MRT, with minor discrepancies attributed to inherent model limitations. This study highlights the potential of aerial thermography to enhance the reliability of MRT simulations across diverse platforms, providing urban planners and designers with a valuable framework for assessing thermal comfort. By bridging a critical validation gap, this work supports the development of more sustainable and thermally comfortable urban spaces, paving the way for broader applications in urban planning and climate adaptation strategies.