An Experimental Investigation of Natural Ventilators for Improving Indoor Air Quality

Based on the theoretical and experimental studies of natural ventilation, the performance of natural ventilators has been analysed. Four types of natural window ventilators and three types of wall ventilators were studied. Experimental results show that the natural ventilators have a greater ventilation effect whilst meeting national and local standards of ventilation for residential buildings in heating or cooling seasons.  The installation of such devices can be a compromise between ventilation and energy loss. Compared with natural window ventilators, wall ventilators are more efficient. The discharge coefficients of the ventilators were calculated, which can guide the design of natural ventilation for residential buildings. However, these coefficients are small on the whole, which indicates that the structure and design of ventilators should be improved because ventilators still have large resistances to airflow. The CO2concentrations in a room with different numbers of ventilators were calculated and the associated indoor air quality was analysed. The results show that CO2 concentrations become stabilized below the health threshold limit of 0.10% and the super-clean limit of 0.07% after a period of ventilator operation. This demonstrates that natural ventilators can supply fresh air and remove CO2 and other pollutants inside a room effectively. Obviously, the utilization of such ventilators will improve home occupants’ health and wellbeing.