相变混凝土空心砌块传热性能实验研究

以填充相变材料的混凝土空心砌块为对象,采用热箱法对其在夏季气候条件下的传热性能进行实验研究。研究发现,相变材料填充在室内侧比填充在室外侧的效果要好,室内平均温度波幅降低10.0%,室内平均温度降低23.7%,室内平均热流降低12.4%。相变墙体对室内温度和热流衰减与室外环境温度波振幅和室外平均温度有关。室外温度波幅越大、室外平均温度与相变材料的相变温度越接近,相变材料对室内温度和热流的衰减越明显。可以根据不同地区的不同气候温度选择对应相变温度的相变材料,以达到更好的节能效果。     

相变控温大体积混凝土抗裂性能研究

混凝土结构温度裂缝,尤其是大体积混凝土工程中的温度裂缝,缺乏有效控制措施.提出了相变控温储能材料机敏控制混凝土结构温度裂缝新的技术途径.通过自行设计的温度裂缝圆环试验测温系统,对普通砂浆和相变控温砂浆抗裂性进行评价,结果表明,相变材料在大体积混凝土中具有较好的控温效果,从而可以提高混凝土抵抗温度裂缝的能力,为解决大体积混凝土温度裂缝提出了新方法.     

癸酸微胶囊相变储能砂浆板的温控模拟与验证

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.     

相变墙体在建筑中的应用研究

利用相变储能建筑材料,可以减小室内温度波动,提高热舒适度,并在一定程度上降低了建筑采暖空调能耗,提高了能源利用效率。本文应用ENERGYPLUS软件对采用相变材料作为墙体的某交通建筑的热舒适性进行数值模拟。研究在不同地区交通建筑墙体和柱子中加入相变材料后,对室内热舒适性的影响。并通过改变相变墙体层的结构、厚度和相变温度,分析不同的参数值对于室内能耗的影响。通过分析和比较,得出如何在不同地区的交通建筑中合理有效的利用相变材料,以促进建筑节能和节资。     

石蜡相变储能砂浆应用性能研究

相变控温储能材料可机敏控制混凝土结构温度裂缝,对石蜡相变砂浆的应用性能进行了研究。采用石蜡颗粒和石蜡乳液作相变材料配制相变储能砂浆,测试了相变储能砂浆的和易性能、不同龄期的抗折强度和抗压强度以及变形性能,并采用压汞法测试其微观孔结构。试验结果表明:石蜡乳液相变砂浆变形性能优于石蜡颗粒相变砂浆,但石蜡颗粒相变砂浆的和易性和强度均优于石蜡乳液相变砂浆,且石蜡颗粒相变砂浆的孔隙率小、孔结构更合理。     

相变储能材料在暖通空调领域的应用研究

对相变储能材料及其选择进行了介绍,并从相变储能地板采暖、相变储能与供暖空调系统相结合的系统、相变蓄热电暖器、相变墙体等方面对相变材料在暖通空调领域的应用研究进行了论述,同时对其在暖通空调领域的应用前景进行了展望。     

一种相变调温砂浆的实验研究

本文以饱和脂肪酸为原料,采用温度曲线法制备了一种相变温度为19-26℃区间段的复合相变材料,并将其以膨胀珍珠岩为载体,用骨胶系封装材料对其进行了封装,最后将封装好的复合相变材料与砂浆结合制备了相变砂浆,并测试了其比热容,评价了相变砂浆的调温功能。结果显示：自制的复合相变材料的相变温度为19.1-26.3℃的温度区间段,其相变潜热为150kJ/kg,经封装材料封装后的复合相变材料的渗漏情况得到了根本性的解决。相变砂浆的相变温度范围仍然介于19~26℃温度区间段,其比热容较大,是普通砂浆的2倍,与普通砂浆相比,相变砂浆的调温性能较好。     

相变蓄能采暖地板的热性能研究

以相变蓄能地板采暖房间为背景,抽象出二维传热方腔模型并进行数值模拟,对比相变地板系统和普通地板系统蓄放热性能差异。分析相变材料导热系数、相变潜热和相变温度等物性因素对地板系统蓄放热性能的影响。研究结果表明相变地板系统蓄放热性能良好,腔内温度波动小,舒适性高。     

脂肪酸分子合金相变材料的热稳定性

以癸酸/肉豆蔻酸分子合金为例,研究了脂肪酸分子合金作为相变材料的热稳定性.利用差示扫描量热技术(DSC)测定了经过56,112,200,400,710次热循环后相变材料的相变温度和相变热.加速热循环实验结果表明:随着热循环次数的增加,相变材料的相变温度和相变热的变化很小,具有很好的热稳定性.分析了利用脂肪酸类相变材料制作空调储能装置的应用效果,发现该装置在储、放能过程中,可使室内温度基本稳定在20℃左右,从而节约能源,减少用户电费支出,并显著降低建筑物室内温度波动,营造健康舒适的室内热环境.     

相变墙体与夜间通风改善轻质建筑室内热环境

将自制复合有机相变材料,与EPS保温材料相粘和,制作成轻质建筑用墙体材料,结合夜间通风技术,在重庆地区进行了含相变材料层和不含相变材料层轻质房间的室内热环境对比实验,以分析相变材料用量、相变温度及相变墙体结构等因素对相变墙体的蓄热、放热性能及对室内热环境的影响。实验结果表明：相变材料应用于轻质房间,能显著增强围护结构的热惰性,提高室内的热舒适性,采取夜间通风技术,可以有效地将日间蓄积的热量散至室外;含相变墙体材料房间与普通房间相比较,室内温度最高降低11℃左右,节能效果显著;室内平均温度符合《野营住房空间与环境参数限值》(GJB 4306 2002)中6.2条规定的3级要求;相变材料用量及相变温度对室内温度的控制效果较为明显,采用不同的相变温度,并将相变墙体房间相变材料用量提高1倍,两轻质房间室内温差最大值从3℃增大至11℃左右;进行相变墙体结构设计时,采取不同相变温度的材料搭配使用可以大幅提高其使用效果。     

脂肪酸/膨胀珍珠岩/石蜡复合相变材料的制备及其在建筑节能中的应用

采用真空吸附法以膨胀珍珠岩为载体吸附脂肪酸相变材料,然后用石蜡包裹制备了脂肪酸/膨胀珍珠岩/石蜡复合相变材料,并将其掺入砂浆中制备了相变砂浆。DSC及SEM分析表明,脂肪酸进入膨胀珍珠岩微孔后其热性能未受影响,且石蜡的包裹效果良好。相变砂浆的分层度和抗压强度均满足GB/T 20473—2006《建筑保温砂浆》的要求。掺入复合相变材料能有效改善砂浆的热性能,温度最高点的延迟时间达24 min,最大降温幅度达4.5℃。     

Experimental study and assessment of thermal energy storage mortar with paraffin/recycled brick powder composite phase change materials

Thermal energy storage recycled powder mortar (TESRM) was developed in this study by incorporating paraffin/recycled brick powder (paraffin/BP) composite phase change materials (PCM). Fourier transform infrared and thermogravimetric analysis results showed that paraffin/BP composite PCM had good chemical and thermal stability. The onset melting temperature and latent heat of the composite PCM were 46.49 °C and 30.1 J·g⁻¹. The fresh mortar properties and hardened properties were also investigated in this study. Paraffin/BP composite PCM with replacement ratio of 0%, 10%, 20%, and 30% by weight of cement were studied. The results showed that the static and dynamic yield stresses of TESRM were 699.4% and 172.9% higher than those of normal mortar, respectively. The addition of paraffin/BP composite PCM had a positive impact on the mechanical properties of mortar at later ages, and could also reduce the dry shrinkage of mortar. The dry shrinkage of TESRM had a maximum reduction about 26.15% at 120 d. The thermal properties of TESRM were better than those of normal mortar. The thermal conductivity of TESRM was 36.3% less than that of normal mortar and the heating test results showed that TESRM had good thermal energy storage performance.     

A novel montmorillonite-based composite phase change material and its applications in thermal storage building materials

A novel composite phase change material (PCM) was prepared by blending an organic PCM with an organic-modified montmorillonite. The thermal characteristics of the composite PCM were close to those of the pure PCM, and 1500 times heating–cooling cycles test showed that the composite PCM had good performance stability. Compared with the pure PCM, the composite PCM exhibited higher heat transfer rate owing to the combination with montmorillonite. The composite PCM had a good compatibility with gypsum powders, and the composite gypsum boards prepared had a function of cutting down energy consumption by decreasing the frequency of internal air temperature swings.     

Modeling and simulation on the thermal performance of shape-stabilized phase change material floor used in passive solar buildings

Shape-stabilized phase change material (PCM) is a kind of novel PCM. It has the following salient features: large apparent specific heat for phase change temperature region, suitable thermal conductivity, no container. In the present paper, a kind of shape-stabilized PCM floor is put forward which can absorb the solar radiation energy in the daytime and release the heat at night in winter. Therefore, in winter the indoor climate can be improved and the energy consumption for space heating may be greatly reduced. A model of analyzing the thermal performance of this shape-stabilized PCM floor is developed. By using the modeling, the influence of various factors (thickness of PCM layer, melting temperature, heat of fusion, thermal conductivity of PCM, etc.) on the room thermal performance was analyzed. The model was verified by the experimental results. The model and the analysis are helpful for the application of shape-stabilized PCM floor in solar buildings.     

Study on in-plane mechanical behavior of cold-formed thin-walled steel-gypsum based self-leveling mortar composite floor

对冷弯薄壁型钢-石膏基自流平砂浆组合楼盖足尺模型进行了平面内低周往复加载试验,研究了组合楼盖的破坏形式、面内承载力、面内刚度以及耗能性能。试验结果表明：冷弯薄壁型钢-石膏基自流平砂浆组合楼盖的整体工作性能优异,具有良好的面内受力性能;组合楼盖因C形边梁与压型钢板之间的螺钉连接发生破坏而导致面内承载力降低,进而发生破坏;组合楼盖的面内刚度和耗能性能均随C形边梁位置处自攻螺钉受剪性能的降低而减小。采用ABAQUS有限元软件对试验模型进行模拟分析,并对验证后的有限元模型进行了变参数分析,研究表明：当砂浆翼板的厚度在20~40mm之间时,厚度的改变对组合楼盖面内受力性能影响较大;当砂浆翼板的厚度在40~80mm之间时,厚度的改变对组合楼盖面内受力性能的影响较小。     

保温隔声砂浆的配制与施工技术

通过在砂浆中掺入废橡胶颗粒、空心漂珠与聚苯颗粒的"三掺"复合技术,利用橡胶颗粒的黏弹性和空心漂珠的复合效应,改善楼板的撞击声压,空心漂珠的空腔结构和EPS颗粒的性能保证了砂浆的保温性能,所配制的保温隔声砂浆体积稳定性较好、热工性能好、隔声性能好,能满足楼板隔音和保温的综合功能要求,在项目试点楼板中进行了应用和性能测试,结果能满足高品质住宅保温和隔声的综合功能要求,形成的保温隔声砂浆施工技术对于楼板保温隔声施工提供了参考。     

Preparation,thermal performance and application of shape-stabilized PCM in energy efficient buildings

Shape-stabilized phase change material (PCM) is a kind of novel PCM. It has the following salient features: large apparent specific heat for phase change temperature region, suitable thermal conductivity, keeping shape stabilized in the phase change process and no need for containers. The preparation for such kind material was investigated and its thermophysical properties were measured. Some applications of such material in energy efficient buildings (e.g., in electric under floor space heating system, in wallboard or floor to absorb solar energy to narrow the temperature swing of a day in winter) were studied. Some models of analyzing the thermal performance of the systems were developed, which were validated with the experiments. The following conclusions are obtained: (1) the applications of the novel PCM we put forward are of promising perspectives in some climate regions; (2) by using different paraffin, the melting temperature of shape-stabilized PCM can be adjusted; (3) the heat of fusion of it is in the range of 62–138 kJ kg⁻¹; (4) for PCM floor or wallboard to absorb solar energy to narrow the temperature swing in a day in winter, the suitable melting temperature of PCM should be a little higher than average indoor air temperature of the room without PCM for the period of sunshine; (5) for the electric under-floor space heating system, the optimal melting temperature can be determined by simulation; (6) PCM layer used in the aforementioned application should not be thicker than 2 cm; (7) the models developed by us are helpful for applications of shape-stabilized PCM in buildings.     

低温热水有源相变墙体辐射供暖的模拟研究

针对低温地板辐射供暖系统应用中的问题,提出了低温热水有源相变墙体辐射供暖新系统,介绍了新系统工作原理及特点;基于相变墙体传热过程的分析,建立了相变墙体蓄、放热过程的传热模型,并应用FLUENT软件对某相变墙体连续4d的周期性蓄、放热特性进行了模拟计算。结果表明:在非对称相变墙体的周期性蓄、放热过程中,左、右两侧墙面的最高温度及最低温度分别为24.8、22.8、23.7、22.5℃,最大及最小热流密度分别为81、65、56、52 W/m2,为低温热水有源相变墙体辐射供暖技术的应用提供了理论基础。     

工业废弃物配制砂浆稠化粉的应用研究

分别采用镁渣粉和粉煤灰作为载体,辅以有机材料配制有机-无机复合砂浆稠化粉,对掺稠化粉砂浆的基本性能及微观结构进行测试。结果表明,利用镁渣粉配制的有机-无机复合砂浆保水性好,粘接强度比不掺稠化粉提高1.5倍,微观结构致密,耐久性好,而且成本低廉,该研究为普通干混砂浆的推广提供了技术保障。     

轻质相变储热墙体材料研究

采用溶胶-凝胶方法制备了以SiO2作为载体的脂肪酸复合有机相变材料,再将它和聚苯乙烯泡沫板复合制成轻质相变储热墙体材料,该材料可克服普通轻质墙体材料储热能力差的缺陷.用轻质相变储热墙体材料作围护结构,建造了试验建筑模型,并进行了隔热控温试验研究.试验结果表明:轻质相变储热墙体材料能有效利用环境温差储放热,其储热控温作用效果明显.