Modeling a mixed-mode cooling system with correlation to operable building facade openings: Mathematical logic integration of computational fluid dynamics and energy models

This study proposes a methodology to integrate natural ventilation into mixed-mode HVAC systems, addressing the gap in design practices that fully incorporate passive cooling techniques. The methodology uses scenario-based analysis, varying the positions of operable openings, and integrates computational fluid dynamics (CFD) and energy models to assess the impact of natural ventilation on cooling demand and energy consumption during the summer. By combining natural ventilation with HVAC systems, the approach ensures a more holistic building design that considers architectural features, thermal comfort, and energy efficiency through a multicriteria framework. Key aspects of the methodology include utilizing precise 3D building models for both CFD and energy analyses, ensuring model accuracy, and overcoming challenges related to data inconsistencies. The adaptive approach to natural ventilation, as a requisite condition, is integrated through a mathematical logic model. This methodology is then applied to a case study building situated in central Türkiye, characterized by a semiarid steppe climate. To assess the impact of operable openings on natural ventilation, four distinct scenarios are created. The mixed-mode system shows substantial energy-saving potential in all scenarios, with the highest achieving up to 94% energy savings. This approach offers a robust solution for enhancing energy efficiency while improving indoor comfort in building designs.