CFD Investigation For A System With Cooled Ceiling And Displacement Ventilation

As people spend more time indoors, heating, ventilating and air-conditioning systems that provide high indoor air quality and thermal comfort become more and more important. The combined cooled ceiling and displacement ventilation system in improving indoor air quality and the superiority of cooled ceiling in improving thermal comfort as well as its saving energy efficiency, which attracts people's attention. After more than 30 years' development, the cooled ceiling and displacement ventilation systems have been widely used in many places besides Germany, Sweden in Europe. However, the research and application of this system is still in beginning in China up to now. In this article, the standard three-dimensional K-ε two equation turbulence model with correctional item of buoyancy effect and SIMPLE algorithm are adopted, and wall function method is used to handle boundary condition. Using the post processing tools of the CFD software, this article analyses the temperature and velocity field in the air-conditioned office and finally evaluates the indoor air distribution comfortable feeling. At last, the influence on the air flow is analyzed where some factors such as the locality of heat source, velocity of air supply, temperature of cooled ceiling are given, which provides a reference for appraisal of the heat comfort characteristic of the system. It has directly meaningful for the design, evaluation and optimization of this type system, and it will benefit to the development of cooled ceiling and displacement ventilation systems in China.