Numerical Simulation Of Indoor Air Distribution In A VAV Air Conditioned Room

After more than 40 years' development, variable air volume systems have been widely used in many places besides North America, Japan and Singapore because of their excellences and have become the most popular and energy- conserving air conditioning systems in commercial buildings. However, due to the supplying air volume change corresponding to cooling or heating load change, such phenomena as uneven temperature and velocity distribution often take place, which lead to bad indoor air distribution and thermo-environment. This article takes the air distribution in a VAV air conditioned office as the research object and with the application of professional CFD software carries out simulations of indoor air distribution in this office.In this article, simulations of air distribution in the VAV air-conditioned office are carried out in the cases of different air-supplying diffusers including slot diffuser, sqaure grille, bar grille and square diffuser to supply air, the standard three-dimensional K - ?two-equation turbulence model with correctional item of buoyancy effect and SIMPLE algorithm are adopted, and wall function method is used to handle boundary conditions. With the momentum method of air-supplying openings, four typical operating conditions in the case of each air-supplying way are simulated. Using the post processing tools of this CFD software, this article analyses the temperature and velocity field in the VAV air-conditioned office and finally evaluates the indoor air distribution, adopting air diffusion performance index (ADPI) .Through the research work of this article, it is shown that CFD technology can efficeintly instruct the design of indoor air distribution and evaluate indoor air quality and ventilating effect; the distribution of heat sources have great impact on indoor air distribution; under variable air volume condition, the indoor temperature and velocity fields are quite even and the thermo-environment is relatively good when using diffusers with coanda effect such as square diffuser and slot diffuser to supply air.