Simulation research on the performance of mixing ventilation of buildings

Abstract

Since the energy crisis in the 1970s, study the efficiency of ventilation system becomes a crucial part in our life. As most of us spend more than 90% of time indoor, indoor air quality (IQA) is increasingly recognized as an essential factor for the prevention of human diseases and the promotion of people's comfort and welfare. Therefore, it is important to design a good ventilation system as it can enhance IQA and save energy. The main purpose of this project is to determine an optimal temperature and velocity contours of mixing ventilation room. Software ANSYS Fluent computational fluid dynamics (CFD) is use to simulate the pressure, temperature and velocity contours in the rooms. The effects of the location of air inlet and outlet, inlet air velocity and direction are analysis in the rooms with the presence of human heat source. A simple rectangular shape represents the human body with heat generation rate is 58 W/m2. From the results in the CFD simulations, we deduce that the direction of air flow normal to the air inlet, air inlet at lower-attitude and air outlet at higher-attitude on the opposite sidewalls are generally performs well than the other configuration. In addition, high velocity of air in the room is desire, as it can potentially improves the thermal comfort and the ventilation rate, however, care must be taken, if the velocity is too high, it is able lead to thermal dis-comfort to the human body. This study enhance the understanding of how the airflow and temperature distribution within a specified space in term of the mixing ventilation.