Abstract

The purpose of this study is to analyze how to minimize the relation between the airflow rate and the Predicted Percentage of Dissatisfied (PPD) in order to establish the minimum PPD of a room depending on the type and rate of production of pollutants. As a consequence, the age of air that minimizes the PPD under such conditions is obtained. The research is focused on the determination of the concentration of pollutants, air velocity, and temperature in the laboratory by using a finite = element program (ANSYS 2011). This method has been validated by comparing the program results with those obtained in a test room. The most fruitful result that can be highlighted is that each room has a typical PPD, which is directly proportional to the ventilation flow rate in the case of velocity and temperature being the causes for discomfort but is inversely proportional when pollutants are considered. The global effect of both causes of discomfort leads to the minimum PPD that can be achieved in the room under certain hygrometric and contaminants conditions. Discussions about the proposed method are finally completed with an application to a laboratory, in which research is conducted through the determination of pollutants concentrations, air velocities, and air temperatures in the room.