Experimental Investigation of a Domestic Solar Chimney with Variable Collector Inclination for Passive Building Ventilation

Abstract

Various passive means of increasing the air movement in interior spaces have received significant attention due to the continuous effort made by the building industry in decreasing the amount of energy consumed due to the conventional means of mechanical ventilation and cooling systems. Several passive ventilation systems are available; however, the solar chimney system has become an efficient alternative since it uses solar energy to produce a convection effect and hence natural ventilation. This work involves the design and analysis of a residential solar chimney under the climate of Jamnagar, Gujarat, India. For experimental development of the unit, the hexagonal solar collector is attached to the central tapered chimney. To evaluate the effect of collector orientation on the heat transfer process, inclined collector operation was performed at angles of inclination equal to 10°, 20°, and 30°, with the same geometrical characteristics. The air temperatures at the specified points were measured with calibrated K-type thermocouples. Theoretical analysis based on energy balance, buoyancy flows, and natural convection equations was also used to evaluate temperature distributions and airflow generation. Based on analytical predictions, air temperature will increase as heat is gained from the sun and collected through the collector. Under typical summer conditions, the outlet air temperature will be higher than the ambient air temperature by about 9–10°C. In the configurations tested, the inclined collector with a slope of 10° showed the highest heat gain and efficiency because it captured solar radiation more efficiently. The analysis also shows that the system can sustain natural ventilation without the use of fans. In general, the findings show that a mini solar chimney can be a viable and energy-efficient alternative for ventilating homes in areas with high amounts of solar insolation. The approach adopted, methodology used, and predictions made in this study will form the basis for future experiments, simulations, and geometry optimization to improve the efficiency of mini solar chimneys.