Development and Numerical Analysis of Active Bottom Surface Cooling (ABSC) for Urban Heat Mitigation and Thermal Comfort Enhancement

The increasing heat in cities poses a significant challenge to urban quality of life and human health. Existing measures to mitigate urban heat islands include both nature-based solutions, such as greening roofs and facades, but also technical approaches, such as reflective surfaces and improved urban ventilation. However, these measures are in several cases insufficient or not applicable, especially in densely built urban areas where space is limited and structural and climatic conditions impose specific requirements. This is exacerbated by competition for space in existing built-up areas due to different usage requirements.

The study which will be presented, proposes a new technical solution: Active Bottom Surface Cooling (ABSC). Unlike passive methods that rely on humidification, shading or radiation reflection, ABSC uses mechanical and thermodynamic processes to enhance thermal comfort for pedestrians. The goal of this method is to lower surface temperatures in urban areas by installing pipes in the top layer of the ground surface, through which a refrigerant (primarily water) circulates. As a result, the technology reduces the energy contained in the surface.

The implementation of pipes into the ground for heating purposes to de-ice surfaces during wintertime has been investigated in some studies. However, the approach of using this technology for cooling purposes has not been examined so far. Thus, numerical analysis of the physical processes involved in ABSC and its impact on the urban climate will be presented. The study will demonstrate how this technology can contribute to reducing temperatures in urban areas and improving thermal comfort in those spaces.