Heating and ventilation efficiencies of a solar chimney integrated system in a low-energy office building.

This article evaluates the heating and ventilation efficiencies of a solar chimney integrated system, comprising a roof solar chimney coupled with an air channel, installed on a two-story office building in Tehran, Iran. Using Computational Fluid Dynamics (CFD) validated by reduced-scale experiments, the study finds that the system can pre-heat indoor spaces during working hours and provide ventilation for about 35% of this time without compromising thermal comfort, particularly when solar intensity exceeds 510 W/m² and ambient temperature is above 10 °C. The optimal ventilation configuration involves inlet apertures at the bottom of the chimney and outlets on the roof with a total opening area of 0.3 m² and an inlet-to-outlet area ratio of 0.3. The solar system is estimated to reduce annual heating demand by 32% (918 kWh) and CO₂ emissions by 1865 kg during the heating season, serving as a passive pre-heating and hybrid ventilation strategy suitable for cold, semi-arid climates.