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同传统空调系统相比,辐射供冷空调系统具有舒适、节能的优点。根据辐射板安装位置的不同可分为顶板辐射和地板辐射供冷,按照实验研究和仿真研究方法对其发展现状进行了概述,并对目前存在的问题和今后的发展趋势进行了探讨和展望。 相似文献
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《节能》2019,(12):92-96
利用CFD对考虑地板传热的三维建筑模型进行模拟,得出换气次数,供回水平均温度和建筑外墙的内表面温度对地板表面温度,辐射换热量和总换热量的影响,以此得出这些因素对地板辐射供冷+置换通风的复合式系统的供冷性能的影响。结果表明:换气次数每降低1h~(-1),地板表面温度升高约0.26℃,辐射换热量升高约1.07 W/m2;供回水平均温度每升高1℃,地板表面温度升高约0.65℃,辐射换热量降低约2.01 W/m~2,外墙的内表面温度每升高1℃,地板表面温度升高约0.25℃,辐射换热量升高约2.08 W/m~2;由于对流换热系数约为0.5~1.0 W/(m~2·K),地板表面的总换热量中对流换热量占比很小,这主要是置换送风时,地板附近空气的垂直温差较小导致的,所以在不考虑地板的供冷能力变化的条件下,其他形式的送风系统可能是更合适的选择。 相似文献
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建立了复合介质地板辐射供冷的数学模型,利用有限容积法对地板层温度场进行了数值模拟。模拟结果表明:地板总热流中对流热流所占比例较小,自然对流下,对流热流占总热流的8%~11%,而通风下占11%~15%;相比于自然对流,通风可以提高对流热流35%以上,但由于室内舒适性对风速的限制,而且对流热流在总热流中所占比例也较小,同时由于通风引起地板表面温度升高,辐射热流减少,因此地板辐射供冷能力增加很小;由于舒适性及结露等条件的限制,地板辐射最大供冷能力约为50W/m~2,因此对于某些冷负荷较大的房间,还需采用其它的辅助供冷方式。 相似文献
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测量地板辐射与下送风复合式供冷系统运行过程中的室内空气温湿度、围护结构表面温度等室内环境参数,分析室内温湿度、热舒适性、系统换热量的变化规律,并对室内空气环境进行影响因素分析。实验结果表明:室内空气绝对湿度较室内空气温度达到稳定需要的时间更短;MRT(mean radian temperature)、OT(operation temperature)和PMV-PPD值在系统开启后第1.0 h减小速率最大,1.5 h后逐渐趋于稳定,此时,PMV约为0.49,PPD约为10%,在热舒适范围内;地板净辐射换热量、对流换热量和总换热量在系统开启后的1.5 h内递增,然后趋于稳定,此时,地板辐射换热量约为37 W/m~2,占总换热量的47%;室内空气温度和作用温度均随室外综合温度、室内发热量、供回水平均温度和送风温度的增加而增加,当室外综合温度较低或较高,或室内发热量较低,或供回水平均温度较低时,室内空气温度和作用温度变化梯度较小,室内空气温度和作用温度随送风温度增加而增加的速率近似呈线性。 相似文献
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地板辐射供冷技术的应用分析 总被引:1,自引:0,他引:1
为了推广地板辐射供冷这一新型节能技术,本文论述了国内外地板辐射供冷技术的发展状况,对地板辐射供冷的实际应用特点、供冷能力、供冷能耗、设计要点进行了分析.辐射供冷要比常规空调系统节能28%~40%且舒适性强.由于可以冷暖联供,在我国南方和北方都有巨大的发展空间. 相似文献
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随着建筑节能的推广和人们对室内生活舒适性要求的提高,采用一种更先进、更节能的室内空气调节系统就显得日趋重要。毛细管型辐射供暖与供冷系统因具有舒适度高、节能效果显著、节省建筑空间等的优点逐渐被广泛采用。对以毛细管为末端的毛细管型辐射供暖与供冷系统布置形式作了介绍,分析了该系统的组成及优点。以辐射供冷为例,探讨了辐射冷系统的末端一毛细管席供冷量的影响因素。 相似文献
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Capillary ceiling radiant cooling panel is a high temperature cooling system, which could pose low energy consumption to meet thermal comfort requirements. A computational fluid dynamics (CFD) simulation study on heat transfer of chilled water flow in the capillary of ceiling radiant cooling panel was performed to attain surface temperature distributions and cooling capacities. Six influencing factors included chilled water inlet parameters, conditions of gypsum plaster and capillary mats structural parameters were considered to obtain the complicated relationships between capillary radiant panel conditions and heat transfer performance. The index of temperature non-uniformity coefficient was proposed to evaluate temperature profiles of ceiling panel surface. The results of the simulation were compared with the values depicted in ASHRAE Handbook and good agreement had been achieved. The average difference between simulation results and the values reported by ASHRAE handbook was within the region of 15%. The research results showed that temperature non-uniformity coefficient was negatively correlated with temperature of chilled inlet water (linear correlation), water velocity (correlation coefficient R = −0.85), and pipe diameter (correlation coefficient R = −0.93), but positively and linearly correlated with tube spacing. Cooling capacity was found to have negative linear correlation with temperature of chilled inlet water, covering thickness and tube spacing. 相似文献
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Radiant floor cooling and heating systems (RHC) are gaining popularity as compared with conventional space conditioning systems. An understanding of the heat transfer capacity of the radiant system is desirable to design a space conditioning system using RHC technology. In the present work, a simplified heat flux model for RHC is developed for both cooling and heating modes of operation. The Artificial Neural Network (ANN) technique is used for the development of the simplified model. Experimental data from literature covering a wide operating range of the RHC is considered for model development and validation. Operating parameters such as mass flow rate (mf), heat resistance (Rs), mean temperature of water flowing through the pipe (Tm), and operative temperature (Top) are considered independent variables influencing the heat flux (qt). The neural network consists of four input layers, one output layer, and one hidden layer with a feed-forward-back-propagation algorithm. A study on the selection of the optimum number of neurons in the range of 1–9 for the hidden layer is also performed. On the basis of the performance parameters, namely, average-absolute-relative-deviation (AARD = 0.11283) percentage, mean-square-error (MSE = 0.00055), and the coefficient of determination (R2 = 0.9984), a hidden layer is modeled with five neurons. 相似文献
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A closed wet cooling tower, adapted for use with chilled ceilings in buildings, was tested experimentally. The thermal efficiency of the cooling tower was measured for different air flow rates, water flow rates, spray flow rates and wet bulb air temperatures. CFD was also used to predict the thermal performance of the cooling tower. Good agreement was obtained between CFD prediction and experimental measurement. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献