Experimental Validation of the Potential of Cross-Ventilation Strategy as a Natural Cooling Technique Integrated in a Real Historic Building

Natural ventilation in hot climates represents a key strategy to reduce the dependence on mechanical cooling systems, especially in historic buildings, where it is essential to balance thermal comfort and heritage conservation. This study analyses the effectiveness of various natural ventilation strategies in a historic building located in Écija, Seville, which is characterised by a warm climate with nocturnal thermal dips. Experimental data obtained during a summer monitoring campaign were used to validate computational fluid dynamics (CFD) models and thermal simulations. In addition, an efficiency index was defined to quantify the indoor temperature reduction. The results show a cooling efficiency close to 40%, achieving an average reduction of 3 °C in the indoor temperature during the summer. Simulations of different modes of operation of natural ventilation show a 30% improvement in comfort hours according to Spanish regulations and a 50% reduction in the thermal difference during non-comfort hours. This work demonstrates that natural ventilation can significantly improve indoor conditions, offering a sustainable and replicable approach for historic buildings in hot climates.