Performance of personalized ventilation in conjunction with mixing and displacement ventilation

Two types of air terminal devices for a personalized ventilation system in conjunction with either a mixing or a displacement total-volume ventilation system were installed in a mock-up of an office. Two occupants were simulated by means of breathing thermal manikins. A constant amount of clean air was distributed between the systems at different combinations of airflow rates. The performance of the systems was evaluated based on the contaminant concentration in and temperature of the inhaled air, as well as temperature, velocity, and contaminant distribution in the occupied zone. The results showed that personalized ventilation will always be able to improve the inhaled air quality in rooms with mixing ventilation. In rooms with displacement ventilation, personalized ventilation will improve the inhaled air quality with regard to pollution emitted from the floor covering. The inhaled air quality with regard to human-produced contaminants, such as virulent agents associated with exhaled air or bioeffluents, may be improved as well. The improvement will depend on the efficiency of the personalized ventilation system and its ability to promote mixing. The experimental data document that the design of air terminal devices for personal ventilation and their use have a large impact on the inhaled air quality and thermal comfort of occupants.