JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2021
·Vol. 147
·期 15
·8177-8188
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IF 4.626
Fang Manting,Zhang Xuelai,Ji Jun,Hua Weisan,Zhao Yi,Liang Jiyuan
In order to solve the phase separation problem of Na 2 S 2 O 3 ·5H2O–CH3COONa·3H 2 O PCM (phase change material), sodium carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), xanthan gum (XG), sodium polyacrylate (PAAS) and polyacrylamide (PAM) were selected as additives. The effects of different proportions of the above thickeners on the supercooling degree, phase separation, phase change temperature and latent heat of Na 2 S 2 O 3 ·5H2O–CH3COONa·3H 2 O system were studied by using the cooling curve and DSC, so as to screen the best thickener for eutectic PCM. The experimental results show that CMC, XG and PAAS can eliminate the phase separation of Na 2 S 2 O 3 ·5H2O–CH3COONa·3H 2 O. Among them, the optimal ratio of CMC, XG and PAAS is 3 mass%, 3 mass% and 1 mass%, respectively. From the perspective of heat storage performance, PAAS is the optimal thickener for Na 2 S 2 O 3 ·5H2O–CH3COONa·3H 2 O. The phase change temperature is 40.5 °C. The subcooling degree is about 14.7 °C, and the latent heat is about 221 J g −1 . The melting time is 15 min. Only PAAS can make Na 2 S 2 O 3 ·5H2O–CH3COONa·3H 2 O eutectic PCM completely exothermic at room temperature, which can not only play the role of thickener to eliminate phase separation, but also is a nucleating agent. After 100 melting-solidification cycles, the change rate of latent heat value was only 5%, and the change rate of phase transition temperature was less than 1%. Considering heat storage performance and cyclic stability, PAAS is the optimal thickener for Na 2 S 2 O 3 ·5H2O–CH3COONa·3H 2 O PCM.
研究领域:
材料科学
·
热能存储
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2018
·Vol. 34
·期 4
·578-583
·
IF 1.248
Song Menglu,Yang Xiangui,Wang Gongying
Polycarbonate diols(PCDLs) with a number average molecular weight( M n ) of 2800 and a narrow polydispersity index(PDI=1.33) were synthesized from dimethyl carbonate(DMC) and 1,4-butanediol(BD) via a two-step process. The influences of the molar ratios of DMC to BD in the feedstock, polycondensation temperature and polycondensation time on the PCDLs preparation were studied. CH 3 COONa showed the best catalytic performance among the catalysts studied. The highest BD conversion of 73.8% and PCDLs yield of 64.7% were achieved under its optimum reaction conditions. Furthermore, based on the results of 1 H NMR, the relationships between the ratio of end groups (—OCH 3 /—OH) of oligomers, the M n and chainend constitute of resultant polycarbonates were also investigated. The results indicate that PCDLs can be synthesized when the oligomers mostly bear hydroxyl end groups. In contrast, it was impossible to prepare PCDLs when the oligomers were enriched with methyl carbonate end groups.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
SOLAR ENERGY
·
2025
·
IF 6.6
Jiachen Li,Biao Hu,Hui Wang,Jinxin Yang,Chunwang Li,Xin Du
A eutectic hydrate salt phase change material composed of NH 4 Al(SO 4 ) 2 ·12H 2 O-CH 3 COONa·3H 2 O was prepared. The eutectic composition, determined experimentally to consist of 92.5 wt% NH 4 Al(SO 4 ) 2 ·12H 2 O and 7.5 wt% CH 3 COONa·3H 2 O, deviated significantly from predictions made by the Scholar’s equation, highlighting the need for optimization of theoretical prediction methods. The eutectic material exhibited promising thermal storage properties, but a significant supercooling degree of 12.98 K was observed. To mitigate this issue, 14 different nucleating agents were evaluated and five nucleating agents were identified as effective in reducing the supercooling degree to below 1 °C. Furthermore, the thermophysical properties of the eutectic phase change materials with five preferred nucleating agents, including phase change temperature, latent heat, volume expansion ratio and thermal storage density, were characterized using differential scanning calorimetry, T-history, and solid–liquid density testing. Among the five preferred nucleating agents, Nano Cu demonstrated the best performance, achieving a high thermal storage density of 223.45 kJ/kg and a minimal volume expansion ratio of 4.92 %. Future studies will focus on optimizing heat transfer characterization and integrating this material into renewable energy-based heating systems such as heat pumps, solar heating systems, and valley electric heating systems to achieve sustainable and efficient heating solutions.
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Storage
·
2024
·
IF 8.9
Qirui Wang,Hongen Nian,Xiaoling Tan,Xiang Wang,Yong Deng,Xiaobin Gu,Ayoub Gounni,Yujing Zhao,Zhaoying Wang,Yongquan Zhou
Filling thermally conductive materials (TCMs) is an effectivity way to enhance the thermal conduction of phase change materials (PCMs). However, it always has negative effects on heat storage behavior of PCMs. Balance of latent heat and thermal conduction capacity plays a vital role in practical application of thermal storage management. To study the effect of dimensional features of TCM on thermal characteristic of PCM, Ag nanomaterials (Ag NMs) which including 0-dimensional Ag nanoparticles (AgNP), 1-dimensional Ag nanowires (AgNW) and 2-dimensional Ag nanosheets (AgNS) acted as TCM, were used to modify the flaky expended vermiculate (EVM-Ag NMs), a series of CH 3 COONa·3H 2 O (SAT)/EVM-Ag NM composite PCMs (SAT/EVM-Ag NM CPCMs) were prepared. It was found that the Ag NMs contributed to the phase change behavior of hydrated salts. Wherein, the SAT/EVM-AgNW CPCM possessed high latent heat (∼200.9 J/g) and great thermal reliability (heat enthalpy loss was 6.9 % after 500 thermal cycles). Besides, Ag NMs also improved the thermal conductivity of the CPCMs. The Ag NWs formed interconnected thermal highways which was benefited to enhance thermal conductivity (0.8153 W·K −1 ·m −1 ). This work provides a new strategy for simultaneously improving the thermal conductivity and heat storage behavior of PCM, finds a new perspective to explore the mechanism of TCMs on phase change behavior and heat conduction of PCM.
研究领域:
材料科学
·
热能工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）