Numerical Simulation of a Displacement Ventilation System with Multi-heat Sources and Analysis of Influential Factors

Abstract

Displacement ventilation (DV) is a promising ventilation concept due to its high ventilation efficiency. In this paper, the application of the CFD method, the velocity and temperature fields of three-dimensional displacement ventilation systems with double heat sources are numerically simulated. The model is verified by experimental data. The results of the study show that thermal stratification characteristics exist in indoor temperature fields. The paper also analyzes the influence of different influential factors, e.g., the distance between heat sources, temperature of heat source, heat characteristics of the wall and outdoor temperature. It was found that the human requirement for comfort is satisfied easily when the distance between heat sources is long. Under the conditions simulated in this paper, when the distance was more than 0.8m, the temperature distribution tended to be average and steady, and it did not change as the distance changed. Second, the temperature change of the thermal current has a large influence on the indoor temperature. The rise in thermal current temperature makes the vertical temperature gradient in the room increase. The upper temperature of the room becomes higher, as does the height of the high temperature air level that lies in the upper part of the room. Finally, both the heat loss of the surrounding structure and the change in outdoor temperature have a large influence on indoor temperature. However, it does not influence the thermal stratification characteristics of DV. The only thing that has changed is the thermal stratification height.