U型毛细管网辐射板顶板辐射供冷空调系统研究

发布时间：2018-07-15 22:00

【摘要】：毛细管网辐射供冷空调系统作为一种低能耗、高舒适性的新型空调方式得到了越来越广泛的研究和工程应用，但是在实际推广中也遇到了一些瓶颈，主要是结露问题、供冷能力不足问题和一次性投资问题。当辐射板表面温度低于室内空气露点温度时，会出现结露现象，因而也制约了辐射板的供冷能力，并导致一次性投资增加。影响毛细管网辐射板供冷能力的因素主要有辐射板自身的结构性因素、运行因素、室内环境温度等，本文针对这三种因素对毛细管网辐射板供冷能力的影响展开研究，建立了U形石膏毛细管网辐射板的三维流-固耦合模型，采用数值模拟软件Fluent模拟毛细管网辐射板表面温度分布规律，通过改变席长、管间距、石膏层厚度等参数，找出影响该种辐射板换热性能的关键性结构因素，通过大量模拟计算，探寻有利于提高石膏毛细管网辐射板供冷能力的最佳结构参数或范围；并在此基础上，研究供水温度、供水流速、室内温度等因素对石膏毛细管网辐射板供冷性能的影响。模拟研究表明：（1）结构性因素中，U型毛细管网石膏辐射板的单位面积供冷量随管间距和石膏层厚度的增大而降低，受席长影响很小，管间距由10mm增加到40mm，，辐射板单位面积供冷量减少18.5W/m~2；石膏层厚度由10mm增加到25mm，辐射板单位面积供冷量减少27.61W/m~2；席长增加1000mm，辐射板单位面积供冷量只减少1.14W/m~2；侧边界条件对辐射板供冷量也有一定影响，侧面绝热比侧面直接接触空气时辐射板下表面温度低0.3℃。（2）运行因素中，U型石膏毛细管网辐射板的单位面积供冷量随供水温度降低而增大，改变供水流速对辐射板单位面积供冷量影响很小，供水12℃比供水20℃时辐射板单位面积供冷量增大64.89W/m~2；供水流速0.1m/s比供水流速0.5m/s时，辐射板单位面积供冷量只降低了1.48W/m~2。（3）毛细管网辐射板单位面积总供冷量随室内温度的升高而增大，室内温度28℃比室内温度23℃时，辐射板单位面积供冷量增大42.28W/m~2。本研究搭建了毛细管网顶板辐射供冷空调系统实验台，将石膏毛细管网辐射板制作成模块化结构，吊装于实验小室顶部，采用辐射吊顶+置换通风/贴附射流模式，通过LabVIEW程序自动控制，以优先控制结露为原则，实验测试了U10石膏毛细管网辐射板在不同供水温度、不同送风方式下，辐射板表面温度分布情况和室内温度分布；并比较了在相同测试条件下U型石膏毛细管网辐射板和U型金属毛细管网辐射板在辐射板表面温度分布和供冷效果方面的差异。实验结果表明：金属辐射板表面温度分布的不均匀度比石膏辐射板小；金属辐射板表面温度最不利点位于辐射板供水口附近，石膏辐射板表面温度最不利点位于辐射板中心部位，应以最不利点温度为依据控制结露；辐射板制冷量受管密度影响较大，相同供水温度下， U10石膏毛细管网辐射板的单位面积供冷量比U20毛细管网金属辐射板高15W/m~2左右；降低供水温度可以显著提高辐射板供冷量，在没有结露危险时，可通过降低供水温度使室内温度在短时间内降低，四十分钟左右即有明显效果；在室温控制方面，金属毛细管网辐射板较石膏毛细管网辐射板反应迅速，在相同条件下，安装金属辐射板的房间比安装石膏辐射板的房间可提前十分钟左右达到设定温度，金属辐射板由于对水温变化反应迅速，可以达到很好的控制精度；石膏辐射板较金属辐射板具有一定的蓄冷能力，可在夜间向室内释放剩余冷量，使空调关闭后室温升高缓慢。模拟结果和实验结果比较吻合。本研究所得结果可以为毛细管网辐射供冷空调系统的设计施工以及进一步研究提供理论依据。
[Abstract]:As a new type of air conditioning system with low energy consumption and high comfort, capillary network radiation cooling air conditioning system has been more and more widely studied and applied in engineering. However, some bottlenecks have also been encountered in the practical popularization, such as condensation problems, insufficient cooling capacity and one-time investment, when the surface temperature of the radiant plate is lower than that of indoor air Condensation occurs when the gas dew point temperature occurs, which also restricts the cooling capacity of the radiant panel and leads to an increase in one-time investment.
The factors affecting the cooling capacity of the capillary network radiant plate mainly include the structural factors of the radiant plate itself, the operating factors and the indoor environment temperature. In this paper, the influence of these three factors on the cooling capacity of the capillary network radiant plate is studied. The three-dimensional flow solid coupling model of the U shaped gypsum capillary network radiant plate is established, and the numerical simulation is used. The software Fluent simulated the surface temperature distribution of the capillary network radiant plate. By changing the parameters of the length, the distance of the tube and the thickness of the gypsum layer, the key structural factors affecting the heat transfer performance of the radiant plate were found. Through a large number of simulated calculations, the optimum structure parameters or scope were explored to improve the cooling capacity of the gypsum capillary network radiation plate. On this basis, the influence of water supply temperature, water supply velocity and indoor temperature on the cooling performance of the gypsum capillary network radiant plate is studied. The simulation study shows that (1) the cooling capacity per unit area of the U type capillary network gypsum radiation plate decreases with the increase of the tube spacing and the thickness of the gypsum layer, and the tube is influenced by the length of the tube very small. The spacing is increased from 10mm to 40mm, the unit area of the radiation plate is reduced by 18.5W/m~2, the thickness of the gypsum layer is increased from 10mm to 25mm, the cooling capacity of the radiation plate is reduced by 27.61W/m~2, the seat length is 1000mm, the unit area of the radiation plate is only 1.14W/m~2, and the side boundary conditions have some influence on the cooling capacity of the radiant plate, and the side adiabatic condition is also adiabatic. The lower surface temperature of the radiant panel is 0.3 degrees centigrade when the air is directly exposed to the air. (2) the cooling amount per unit area of the U type gypsum capillary network radiation plate increases with the decrease of the water supply temperature. The change of water supply velocity has little effect on the cooling amount per unit area of the radiant plate, and the cooling capacity of the radiation plate per unit area of the water supply at 12 C is 64 more than that of the water supply at 20 C. .89W/m~2; when the flow velocity 0.1m/s is 0.5m/s, the cooling amount per unit area of the radiation plate is only reduced by 1.48W/m~2. (3), the total cooling capacity per unit area of the capillary network radiation plate increases with the increase of the indoor temperature. The cooling capacity of the radiation plate unit area is increased by 42.28W/m~2. when the indoor temperature is 23 degrees centigrade than the indoor temperature.
In this study, the experimental platform of the capillaries radiation cooling air supply air conditioning system was set up. The gypsum capillary network radiation plate was made into a modular structure, which was hoisted to the top of the laboratory. The radiation ceiling + displacement ventilation / attached jet mode was adopted, and the LabVIEW program was automatically controlled to control the condensation as a priority, and the U10 gypsum capillary was tested. The temperature distribution of the radiant plate surface and the temperature distribution on the surface of the radiant plate at different water supply temperatures and air supply modes are compared. The difference between the surface temperature distribution and the cooling effect of the U type gypsum capillary net radiant plate and the U type metal capillary network radiant plate on the surface of the radiant plate under the same test conditions is compared. The surface temperature distribution of the metal radiant plate is smaller than that of the plaster plate; the most unfavorable point on the surface temperature of the metal radiant plate is located near the water supply port of the radiant plate, the most unfavorable point on the surface temperature of the gypsum radiant plate is located at the center of the radiation plate, and the condensation should be controlled on the basis of the most unfavorable point temperature; the cooling capacity of the radiant plate is greatly influenced by the tube density. Under the same water supply temperature, the unit area per unit area of U10 gypsum capillary network radiation plate is about 15W/m~2 higher than that of the U20 capillary metal plate. Reducing the water supply temperature can significantly increase the cooling capacity of the radiant plate. When there is no danger of condensation, the temperature of the water supply can be reduced in a short time by reducing the water supply temperature, which is about forty minutes or so. In the room temperature control, the metal capillary network radiant plate is more responsive than the gypsum capillary network radiant plate. Under the same condition, the room with metal radiant plate can reach the setting temperature about ten minutes earlier than that of the plaster radiation plate. The metal radiant plate can be achieved very well due to the rapid reaction of the water temperature change. The result of this study can be used for the design, construction and further study of the capillary network radiation cooling air conditioning system. Provide a theoretical basis.
【学位授予单位】：天津商业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU831.3

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