Single solar chimney technology as a natural free ventilator; energy-environmental case study for Hong Kong

The importance of ventilation is highlighted through the recent COVID pandemic particularly in populated societies with crowded buildings. The application of single solar chimney ventilator with and without fin, at different tilt angles, is evaluated for Hong Kong climate using transient 3D validated numerical simulation in present research from energy and environmental viewpoints. The results show that the ventilation performance of the solar chimney ventilator is significantly enhanced by selecting an optimum value for the tilt angle of the chimney. Moreover, the maximum air mass flow rate increases from 0.06 to 0.14 kg/s by reducing the tilt angle from 80 degrees to 20 degrees. Energy saving performance of the solar chimney ventilator with tilt angle of 20 degrees is around 144% higher than that of the solar chimney ventilator with the tilt angle of 80 degrees. During the morning time (sunrise to noon), the highest performance is achieved under the tilt angle of 40 degrees. From the environmental viewpoint, the solar chimney ventilator with the tilt angle of 20 degrees and 40 degrees can prevent 0.098 kg and 0.108 kg CO2 production through the morning. Prevention of the CO2 production through the afternoon is 0.209 kg and 0.151 kg for the mentioned tilt angles respectively.