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石蜡储能颗粒粒度分布与相变储能复合石膏板导热系数的关系研究 总被引:3,自引:0,他引:3
以石蜡作为储能介质,不同粒径分布的轻质多孔陶粒作为吸附基体,通过包封制备定形相变储能颗粒,并以石膏为基体材料,制备了相变储能复合石膏板.采用数码相机及图像处理软件和导热系数测试仪分别测试储能颗粒的粒度分布和复合石膏板的导热系数;运用灰色关联原理分析计算储能颗粒的粒度分布与复合石膏板导热系数的灰色关联度,分析了储能颗粒各粒度级配与相变储能材料的导热系数的关系.结果表明,当温度在石蜡相变温度附近时,粒级为2~3 mm的粒子对储能复合石膏板导热系数有显著的增大作用;当温度远高于相变温度时,粒级为4~5mm的粒子对储能复合石膏板导热系数有较强的减小作用. 相似文献
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相变储能复合材料相对导热系数研究 总被引:1,自引:0,他引:1
为了科学评价相变储能复合材料在建筑工程中应用的节能效果,根据相变材料的性质,从能量的角度提出了相对导热系数的概念及其测试方法——能量补偿法.利用自行研发的测试装置,对绝热材料导热系数参比板、普通石膏板、膨胀珍珠岩复合板以及相变石膏板进行了测试,并采用所述相对导热系数法来表征其导热性能.试验表明:所提方法不仅可测相变储能复合材料的相对导热系数,而且对普通保温材料也适用,能较好地实现相变储能复合材料的热工性能评价,为其在建筑节能工程中的应用提供技术支持. 相似文献
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为协同提高储能砂浆的热性能与力学性能,采用压力成型方法制备了硫铝酸盐水泥基相变储能砂浆,并通过差示扫描量热法(DSC)、导热系数测试、红外热像法测试、强度试验及扫描电子显微镜(SEM)等方法,研究了压力成型相变储能砂浆的相变潜热、相变温度、导热性能、储热能力、力学强度及微观结构.结果表明:该相变储能砂浆的界面结合紧密、密实度高、导热能力强,并且在等相变材料含量下,具有更高的力学强度;当相变材料质量分数为25%时,与浇筑成型相比,压力成型可使相变储能砂浆在10℃和30℃下的导热系数分别提高60.2%和69.1%,且28d抗压强度、抗折强度分别提高27.7%和40.0%. 相似文献
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泡沫材料导热性能评价与测试方法密切相关,为阐明瞬态法和稳态法对测试无机泡沫材料导热系数的适应性,在介绍两种导热系数测试方法原理基础上,以干密度200~300 kg/m3的自制泡沫地质聚合物和市售泡沫混凝土为研究对象,比较了两种测试方法对含宏观气孔(φ≥0.5 mm)的无机泡沫材料导热性能测试结果及其差异。结果表明:(1)在测试不同干密度等级无机泡沫材料导热系数时,稳态法比瞬态法低0.0085~0.0205 W/(m·K),而且这种差别随材料干密度增大(导热系数增大)而增大;(2)干密度等级相同时,自制泡沫地质聚合物具有与市售泡沫混凝土相当或更低的导热系数,可望用于新型建筑保温材料;(3)稳态法比瞬态法更适用于具有宏观气孔无机泡沫材料导热性能测定。 相似文献
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以癸酸微胶囊相变储能砂浆板为研究对象,采用试验测试结合数值模拟的方法,验证癸酸微胶囊相变储能砂浆板在建筑围护结构中的温控效果.结果表明:与未掺癸酸微胶囊时相比,掺入2%和4%癸酸微胶囊的相变储能砂浆板导热系数分别降低了8%和21%,而蓄热系数分别升高了3%和11%.在数值模拟与试验验证中,相变储能砂浆板平面温度呈梯度分布,平面整体温度差异不大;随着癸酸微胶囊掺量的提升,相变储能砂浆板在相同时刻的温度上升速度变慢,在同温度下需要的加热时间增加;与未掺癸酸微胶囊的相变储能砂浆板相比,掺4%癸酸微胶囊的相变储能砂浆板相变完成时间延迟20min左右,说明掺入癸酸微胶囊能使相变储能砂浆板的温度增长出现明显延迟,癸酸微胶囊相变储能砂浆板具有良好的温控效果,且该效果随着癸酸微胶囊掺量的增加而变得更好. 相似文献
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本文介绍了几种导热系数的测定方法,包括稳态法和非稳态法,并分析了影响导热系数高低的因素,主要包括含水率、密度、温度、结构和传热方向等,并通过试验进行了验证。 相似文献
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随着能源供求失衡日益加剧,建筑蓄能节能的重要性不断凸显。营造具有高效蓄能及可调节能力的可持续蓄能围护结构,对于建筑节能具有重要意义。本文从居住者的热舒适需求出发,通过反问题思路,提出了被动式及主动式建筑中可持续室内环境营造的一些新思路和新方法。研究发现,被动式建筑围护结构理想热质体热性能具有相变材料的特征,即热容随温度的分布接近δ函数形式。并进一步开展了建筑用相变材料的研发及应用研究,研制了建筑用定形相变材料和微胶囊化相变材料,克服了传统相变材料易泄露和导热系数偏低等缺点。最后,提出了主被动式建筑围护结构和相变材料一体化的系统应用方案,并通过实验及模拟验证了其节能舒适效果,为相变材料和建筑蓄能围护结构一体化的设计及应用提供指导。 相似文献
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The technical feasibility of an innovative solar collector is studied in this paper. A phase change material (paraffin) is
used in the solar collector to store solar energy. This type of system combines both collection and storage of thermal energy
into a single unit. The major advantages of the phase change stores are their large heat storage capacity and isothermal behavior
during the melting and solidifying processes. A negative aspect of paraffin is its low thermal conductivity which increases
the melting and solidifying time for paraffin energy storage. In this paper, new aluminum foams infiltrated with paraffin
are presented. It presents a two dimensional model describing the melting and solidifying processes of paraffin while accounting
for both phase change heat transfer and natural convection. Apparent heat capacity method was used to simulate the melting
and solidifying processes of paraffin. The simulation results show that the motion of the hot liquid paraffin plays an important
role in increasing the heat transfer between paraffin and top surface of solar collector. The shape profile of the pure paraffin
solid-liquid interface is determined by the synergistic relationship between its temperature and velocity field. Though aluminum
foams impregnated with paraffin will limit motion of the hot liquid paraffin, the heat transfer ability is greatly improved.
The distributions of the temperature in the paraffin with aluminum foams are more homogeneous compared with that of the paraffin
without aluminum foams. Thus, use of aluminum foams infused with paraffin improves heat transfer and enhances paraffin’s melting
and solidifying rates. 相似文献
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Stearic acid/silica fume composite as form-stable phase change material for thermal energy storage 总被引:2,自引:0,他引:2
The aim of this research is to prepare a novel form-stable composite phase change material (PCM) for the latent heat thermal energy storage (LHTES) in buildings, passive solar space heating by impregnating of stearic acid (SA) into silica fume (SF) matrix through the technique of solution impregnation. The structure, thermal properties, thermal reliability, thermal conductivity and heat storage or release performance of the composite PCM were determined by scanning electron microscope (SEM), Fourier transformation infrared (FTIR), differential scanning calorimetry (DSC) and thermal cycling test analysis technique. The results show that the form-stable composite PCM has the optimal effect, preventing the leakage of SA from the composite, emerges when the SA and SF mass ratio is 1:0.9. The SA loaded on the matrix surface by physical attraction with the mass ratio of 47% during the preparation process. The latent heat of the composite PCM is measured as 82.53 J/g for the melting process and 84.47 J/g for the freezing process, respectively, which indicate the heat storage ability of composite is connected with the mass ratio of SA in composite. The results of DSC, FTIR and thermal cycling test are all show that the thermal reliability of the composite PCM has an imperceptible change. The increase of thermal conductivity was also confirmed by comparing the melting time, freezing time and phase change time of the composite with that of SA. All of the conclusions indicate that the composite has a better thermal conductivity and good thermal and chemical stability. 相似文献
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为了研究陶粒混凝土在不同影响因素下的导热系数变化规律,利用单因素试验方法,通过稳态法中的热流计法(DRPL-Ⅱ型导热系数测定仪)对陶粒混凝土试件进行了导热系数试验,考察了砂率、粉煤灰掺量、浸水时间三个影响因素对陶粒混凝土导热系数的影响。结果表明:陶粒混凝土的导热系数随着砂率的增大而减小;陶粒混凝土的导热系数随着粉煤灰掺量的增大而先减小后增大;陶粒混凝土的导热系数随着浸水时间的增加逐渐增大并趋于稳定。研究结果为陶粒混凝土结构内部温度场的精确计算以及保温隔热性能的控制提供更为重要的理论依据。 相似文献
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为了研究强化相变蓄热器的换热情况,搭建了矩形腔体内填充泡沫金属/石蜡的实验台,在恒壁温条件下,进行了泡沫金属/石蜡复合相变材料的融化蓄热实验.根据实验数据绘制了不同加热温度下石蜡内部温度随时间变化曲线,分析了腔体内自然对流对温度分布的影响、传热温差对蓄热时间的影响.结果表明,泡沫金属的高导热性能强化了石蜡在腔体内的融化... 相似文献