An Research On Air Distribution Design Optimization Of Different Large Spaces

In the practical engineering, large spaces building can take a variety of airflow organization way, the most common of which are on the entire room air supply air conditioning form and side air supply air conditioning form stratification. At present, there are many problems for the above two types of air distribution mode, which are the calculation method, the distribution effect and the energy consumption. So carrying out the design method and optimizing the design scheme have the important value of engineering application, and the research results have a certain guiding significance in engineering design.First, this paper aims at the characteristics of the airflow organization calculation method, then the calculation formula are simplified and transformed, by introducing the dimensionless quantity. To realize the airflow organization, the calculation charts of the two airflow organizations are drawn, using the simplified calculation method. Through the energy saving rate calculation of stratified air conditioning, The result show that when the relative stratified heightθ >0.5, the energy saving rate is 9.0-10.2%, which is greater than 10%; when the relative stratified height θ ≤0.5, the energy saving rate is 12.6%-18.9%, which is less than 10%, so the energy saving effect is obvious. Above show that the relative stratified height should be controlled 0.5 below as far as possible in the process of design of stratified air conditioning.Then, the concept of “the characteristics of load physical” is introduced in the paper, according to the different load composition and distribution characteristics of large space buildings; For the actual “load characteristics” of different functions of large space building, the large space building is divided into three types and the paper points out the typical “the characteristics of load physical”. Through the CFD numerical simulation analysis of different airflow organization forms for three kinds of large space building which have the typical “the characteristics of load physical”, the paper get the suitable airflow organization form of the three large space buildings:(1) the mechanical processing plant should give preference to the stratified air conditioning mode, whose “the characteristics of load physical” is the block heat source;(2) the lecture hall should select the entire room air conditioning mode, whose “the characteristics of load physical” is the horizontal plane heat source;(3) the atrium chose the stratified air conditioning, whose “the characteristics of load physical” is the vertical plane heat source, so it can combine comfort with energy saving.The last,based on the actual construction size and reasonable assumptions of a underground hydropower generator layer, this paper used FLUENT software to discuss the airflow organization via the calculation model of the entire room air conditioning and the stratified air conditioning. From the analysis of simulation results, the number of diffuser has no effect on the average temperature of the workspace under the entire room air conditioning, but the average velocity will decreases in the workspace as the number of diffuser increases. Increasing the number of diffuser can promote the uniformity of temperature field and velocity field in the workspace. When the diffusers of stratified air conditioning are staggered arrangement, the collisions intensity between the supply air jet can be reduced effectively, so the heat transfer and the waste amount of cold air can be decreased also. It can improve the energy saving effect of stratified air conditioning.