Simulation And Analysis For Ice Storage Cold Air Distribution System Of The Underground Market

Along with the national economy unceasing development and thepopulation sharp growth, the building is extending to the underground space and the sky,making much more use of the underground space. Especially for the recent years, more and more countrys begin constructing the underground construction. The scale becomes more and more big and the application scope is more and more broad. For example, the subsurface storage, the underground market, the underground park, the underground hospital and so on. The domestic underground market and the underground business street is also developing very quickly.It has became the important constituent of the major and medium citybusiness net.The electricity load of the air conditioning on these places is increasing rapidly to exert the huge pressure on the city electrical network. Specially , the electricity using at peak and valley time has made the imbalanced phenomenon to be more prominent. Under this background, the ice storage that can effectively balance the peak and valley begins to develop in our country gradually. Because the investment expenses of the pure ice storage project is much more than the conventional air-conditioning project, so the ice storage project used with cold air distribution technology enables the investment expenses to reduce greatly, evenpossibly lower than the conventional air conditioning project. At present, two main reasons restricting the cold air distribution technology to develop in our country is shown as follow: (l)The air mass of cold air distribution is littel,so it may create indoor air quality to be low; (2) the temperature of cold air distribution is low, so it would make persons in the room have the cold wind blow feeling. For VAV systems,the value 70% is usually used for the minmum air rate in project designs.But the research for the underground markets is still limiting.In this thesis, the tianfu squareunderground market in Chengdu is taken as an object. First, the brief analysis to the underground commercial construction load characteristic is carried on, and then the laws' differences between normal system and the new stage is discussed.Based on the Navier-Stokes equation and and RNG κ-εturbulent model, ice storage with cold air distribution is researched using finite volume method (FVM) in this thesis. STAR-CD, the commercial computational fluid dynamics (CFD) software is used to simulate the distritution of temperature, velocity under different air conditioning conditions. By considering the thermal transfer processes such as the heat release of persons, equipments and the solar radiation, and etc., a model using square diffusers was established. With the relation between export momentum and indoor air quality, the rational range of dimension for air diffussur is discussed. Then influence of air rate on the room temperature,air velocity and thermal comfortable feeling were thoroughly studied. Finally, some reasonable proposal was presented. The air-conditioning system minimum air rate is to reach under the comfortableness request to achieve energy conservation's purpose finally.