石蜡/膨胀珍珠岩复合相变储能材料的研究

以膨胀珍珠岩为吸附材料,石蜡为相变储能材料,制备了石蜡/膨胀珍珠岩复合相变储能材料;运用扩散-渗出圈法确定了膨胀珍珠岩的最佳吸附量为65%（质量分数,下同）;采用DSC及SEM对最佳吸附量的石蜡/膨胀珍珠岩复合相变储能材料的相转变过程及微观结构进行研究。结果表明：膨胀珍珠岩的内部孔隙基本被石蜡完全填充,其自身成为了密实颗粒;复合相变储能材料的相变温度与石蜡的相变温度基本一致,其相变潜热与对应质量分数下石蜡的相变潜热相当。     

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℃。     

相变石蜡复合膨胀珍珠岩的制备与表征

通过扫描电子显微镜(SEM)与差示扫描量热仪(DSC),采用真空吸附法对复合材料微观结构及热性能进行了研究。试验结果表明:经过吸附后,膨胀珍珠岩的所有微孔基本被石蜡填充;复合相变储能材料的相变焓相对于单一石蜡的相变焓有所降低;石蜡与膨胀珍珠岩复合的最佳质量比为3∶1。     

复配石蜡/膨胀珍珠岩相变颗粒的热性能研究

通过固体石蜡与液体石蜡熔融混合复配制成低熔点相变石蜡,其中以固液比1:1制备的相变石蜡熔点为25.1℃,潜热为104.3kJ/kg.500次冷热相变循环后石蜡的热物性仅轻微衰减,热化学稳定性好.利用多孔膨胀珍珠岩吸附熔融石蜡可以制备石蜡,膨胀珍珠岩相变颗粒,其中石蜡:珍珠岩质量比为3.5:1.0的相变颗粒不团聚,石蜡含量最高为77.78%.通过SEM、FT-IR、DSC等表征手段测得:该相变颗粒熔点为25.6℃,潜热为80.3k/Ag,具有优良的热物性;相变颗粒仅仅是石蜡和膨胀珍珠岩的嵌合,可以加入到墙体材料中用于建筑节能.     

相变石蜡复合膨胀珍珠岩保温隔热干粉砂浆

采用膨胀珍珠岩为担载介质,相变石蜡为储能物质,以乳化法工艺实现了相变石蜡在膨胀珍珠岩中高效、稳定与大容量的担载,比较直接吸附法提高了3.5倍.并以此复合相变膨胀珍珠岩,制备了新型相变储能保温隔热干粉砂浆.以此干粉砂浆为原料,所研制的相变储能保温隔热材料具有比热容和蓄热系数大,导热系数较小的特点,同时相变石蜡在相变储能保温隔热板材中表现出优秀的工作稳定性能和防渗出稳定性能.     

石蜡-膨胀珍珠岩复合相变材料研究

以石蜡熔合膨胀珍珠岩制备复合相变材料,对复合相变材料的容留量、渗透性以及耐久性进行了研究.研究结果表明,石蜡-膨胀珍珠岩复合相变材料耐久稳定性良好.容留量结果表明浸渍时间为2 h,浸渍温度为50 ℃时,石蜡与膨胀珍珠岩融合较好.     

石膏基相变储能材料的性能研究

以石蜡为相变储能材料,膨胀珍珠岩为吸附材料,制备石蜡/膨胀珍珠岩复合相变储能材料。DSC结果表明：复合相变储能材料的相变温度与石蜡的相变温度基本一致,其相变潜热与对应质量分数下石蜡的相变潜热相当。将复合相变储能材料与石膏复合制备石膏基相变储能材料试样,并对其力学性能、吸水率及控温特性进行测定。试验结果表明：随着复合相变储能材料含量的增加,试样的抗压及抗折强度呈持续下降趋势;试样2h吸水率呈先减小后增大的趋势;试样控温效果显著增强,能有效地将温度控制在适宜范围内。     

石蜡/膨胀珍珠岩基相变储能砂浆调温性能的研究

研究了石蜡/膨胀珍珠岩基相变水泥砂浆板的力学性能及导热系数,测定了不同制备方式的石蜡/膨胀珍珠岩基相变水泥砂浆板对房屋模型室温的调控性能。结果表明:相对于普通水泥砂浆,石蜡/膨胀珍珠岩基相变水泥砂浆具有良好的调温性能,可以有效降低室内的温度波动和减小最大温度值,达到建筑节能的目的。插层法的调温性能优于混掺法,且相变材料掺量越大,调温效果越明显。     

复合相变蓄能屋顶的制备及性能研究

以石蜡和膨胀珍珠岩为原材料,采用真空吸附原理制备了复合相变颗粒(膨胀珍珠岩/石蜡),对其进行了SEM分析、FTIR分析、DSC分析、TG分析,并进行了导热系数的测定与分析。采用模压定型法制备了复合相变板材,将其与屋顶结合制成了复合相变蓄能屋顶,对其进行了实际应用测试。结果表明:石蜡和膨胀珍珠岩靠分子间作用力进行物理上的嵌合,复合相变颗粒保持了石蜡高相变焓值的热物性,且具有较高的热稳定性。复合相变蓄能屋顶具有良好的蓄能效果,表现出较高的热惰性,能够维持室内温度在较小范围内波动。     

粒状复合相变材料隔热性能实验研究

对采用真空浸渍法制备膨胀珍珠岩为基质的相变材料的隔热性能进行实验研究。研究结果证明制备的复合相变材料的隔热性能均优于珍珠岩,在研究条件下,用相变温度为25℃的石蜡制备的复合相变材料具有更好的隔热性能。     

Stearic acid/silica fume composite as form-stable phase change material for thermal energy storage

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.     

使用泡沫铜增强相变材料换热性能的实验研究

针对有机相变材料(PCM)导热系数较低的缺点,通过实验研究了添加通孔泡沫铜金属材料增强相变材料导热系数的方法。选择脂肪酸二元低共熔混合物相变材料作为蓄热介质,通过对其进行DSC测试分析,得到其相变温度和相变潜热。对壳管式潜热蓄热系统填充介质为纯PCM与PCM/泡沫铜复合相变材料两种工况下的熔化过程进行对比实验研究。实验数据表明,与纯PCM蓄热系统相比,添加泡沫铜的蓄热系统换热性能得到增强,整个蓄热器内PCM达到相变温度的时间仅为纯PCM系统的22.5%。     

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.     

屋面相变砖实验研究

利用相变过程中的潜热,相变材料能在建筑屋面上做隔热应用.利用差示扫描量热仪对石蜡类相变材料进行了实验研究,研究一种液体类有机材料分别与固体石蜡A和固体石蜡B混合制成复合相变材料的相变温度和相变潜热,并进行DSC分析.结果表明,复合相变材料与高密度聚乙烯以70:30的比利用熔融共混法制备定形相变材料,能将复合相变材料包裹住,使其在发生固一液相变过程中不会发生渗漏.且高密度聚乙烯的存在对复合相变材料的热物理性能影响很小.     

地板采暖系统用复合相变砂浆填充材料研究

阐述了相变砂浆作为填充层材料在地板采暖中应用的意义,采用溶胶-凝胶法制备了以二氧化硅为载体的复合有机相变颗粒材料,配制了相变石膏砂浆.利用地板采暖试验间进行了相变砂浆和普通砂浆的地板采暖试验,以验证相变砂浆地板采暖系统的蓄放热性能,并对地板表面和室内的温度影响进行了试验分析.通过试验验证了新型相变砂浆作为填充层材料应用到地板采暖是切实可行的,在较好改善室内温度环境的同时降低了地板采暖系统的荷载和厚度.     

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.     

Preparation and properties of gypsum-based heat storage and preservation material

The paraffin/expanded perlite shape-stabilized phase change material (PCM) was prepared by absorbing paraffin into pores of expanded perlite with vacuum adsorption method (VA method). The gypsum-based heat storage and preservation material was prepared by mixing the prepared paraffin/expanded perlite shape-stabilized PCM and gypsum. Scanning electron microscopy (SEM) was used to investigate the influence of the VA method and free adsorption method (FA method) on the microstructure of the paraffin/expanded perlite PCM. Differential scanning calorimetry (DSC) and exudation experiment were used to test the thermal property and shape-stability of the paraffin/expanded perlite PCM, respectively. The thermal conductivity, bending strength and compressive strength were also tested. The results showed that paraffin was uniformly distributed in pores of expanded perlite in the paraffin/expanded perlite PCM prepared with the VA method. The paraffin/expanded perlite PCM had satisfied shape-stability. The thermal conductivity of gypsum was decreased by addition of the paraffin/expanded perlite PCM. The adsorption amount of paraffin had little effect on the bending strength and compressive strength of the gypsum-based heat storage and preservation material.     

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.     

Preparation and characterization of fatty acid ester/building material composites for thermal energy storage in buildings

In this study, fatty acid ester/building material composites as novel form-stable phase change materials (PCMs) were prepared by absorbing liquid fatty acid esters into porous network of conventional building materials. In the composite erythritol tetrapalmitate (ETP) and erythritol tetrastearate (ETS) esters were used as PCM for thermal energy storage, and cement and gypsum used as supporting material. The composite PCMs were characterized using scanning electron microscope (SEM) and Fourier transformation infrared (FT-IR) analysis technique. The SEM results showed that the esters were confined in the porous network of the cement and gypsum. Thermal properties and thermal stabilities of the composite PCMs were determined by using differential scanning calorimetry (DSC) and thermal gravimetric (TG) analysis techniques. DSC results showed that the melting temperatures and the latent heats of the prepared composite PCMs were in range of 21.6-32.3 °C and 35.9-43.3 J/g, respectively. TG analysis indicated that the composite PCMs had good thermal stability. The thermal cycling test including 1000 heating and cooling process was conducted to determine the thermal reliability of the composite PCMs and the test results revealed that the composite PCMs have good thermal reliability and chemical stability.