The Experts below are selected from a list of 108375 Experts worldwide ranked by ideXlab platform
Yutang Fang - One of the best experts on this subject based on the ideXlab platform.
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preparation and properties of Phase Change Temperature tuned composite Phase Change material based on sodium acetate trihydrate urea fumed silica for radiant floor heating system
Applied Thermal Engineering, 2019Co-Authors: Wanwan Fu, Xianghui Liang, Shuangfeng Wang, Zhengguo Zhang, Yutang FangAbstract:Abstract In this work, a novel Phase Change Temperature-tuned composite Phase Change material (PCM) for the PCM floor was developed by using sodium acetate trihydrate-urea non-eutectic mixture as PCM and fumed silica (SiO2) as both supporting material and Temperature regulator. The thermoregulation mechanism of SiO2 and the properties of the resulting composite PCM were studied. The results showed that the addition of SiO2 could adjust melting Temperature of the non-eutectic mixture from 34.36 to 48.45 °C, reduce supercooling degree and prevent leakage. With SiO2 mass fraction of 30%, the composite PCM had a suitable melting Temperature (35.75 °C), high latent heat (151.6 kJ·kg−1) and low supercooling degree (1.14 °C). Meanwhile, the composite PCM possessed a good form stability and excellent thermal reliability and favorable thermal conductivity. Considering the above, the novel composite PCM has a great potential for the PCM floor. It is also expected that the present work can provide a new insight into tailoring Phase Change Temperature of PCMs.
Fangshu Liu - One of the best experts on this subject based on the ideXlab platform.
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Study on rheological properties and Phase-Change Temperature control of asphalt modified by polyurethane solid–solid Phase Change material
Solar Energy, 2019Co-Authors: Kun Wei, Xiaoqing Wang, Wenshuo Shi, Shiyu Duan, Fangshu LiuAbstract:Abstract Polyurethane solid–solid Phase Change material (PCM) with low Phase Change Temperature is synthesized via prepolymer method. The synthetic polyurethane solid–solid PCM had lower crystallinity than PTMEG2000. The polyurethane solid–solid PCM was still in solid state during the heating process, and no liquid leakage was observed. After many Phase Change cycles, the polyurethane solid–solid PCM exhibited good stability of Phase Change cycles. Hence, the asphalt modified by polyurethane solid–solid PCM was prepared by high-speed shearing method. With increasing polyurethane solid–solid PCM proportion, the high Temperature deformation resistance of modified asphalt gradually increased. At low Temperature ( 3 wt%, the specific heat capacity of the modified asphalt had an evident peak ranging from 13 °C to 25 °C. In the range of the proportion, the coefficient of the heat conductivity of the modified asphalt gradually increased with increasing PCM content. During the cooling process, the modified asphalt cooled relatively slow before the Phase transition of the polyurethane solid–solid PCM. With continued decrease in the Temperature, the Phase transition of the polyurethane solid–solid PCM occurred, and the cooling rate of the modified asphalt further decreased. With increasing polyurethane solid–solid PCM content, the Temperature control ability of modified asphalt and the efficiency of Temperature control gradually increased.
J S Saini - One of the best experts on this subject based on the ideXlab platform.
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an analysis of a packed bed latent heat thermal energy storage system using pcm capsules numerical investigation
Renewable Energy, 2009Co-Authors: Felix A Regin, S C Solanki, J S SainiAbstract:This paper is aimed at analyzing the behavior of a packed bed latent heat thermal energy storage system. The packed bed is composed of spherical capsules filled with paraffin wax as PCM usable with a solar water heating system. The model developed in this study uses the fundamental equations similar to those of Schumann, except that the Phase Change phenomena of PCM inside the capsules are analyzed by using enthalpy method. The equations are numerically solved, and the results obtained are used for the thermal performance analysis of both charging and discharging processes. The effects of the inlet heat transfer fluid Temperature (Stefan number), mass flow rate and Phase Change Temperature range on the thermal performance of the capsules of various radii have been investigated. The results indicate that for the proper modeling of performance of the system the Phase Change Temperature range of the PCM must be accurately known, and should be taken into account.
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latent heat thermal energy storage using cylindrical capsule numerical and experimental investigations
Renewable Energy, 2006Co-Authors: Felix A Regin, S C Solanki, J S SainiAbstract:This paper is aimed at analyzing the melting behavior of paraffin wax as a Phase Change material (PCM) encapsulated in a cylindrical capsule, used in a latent heat thermal energy storage system with a solar water heating collector. The heat for melting of PCM in the capsule is provided by hot water surrounding it. Since it is observed experimentally that the Phase Change occurs in a range of Temperature, the present analysis considers this range instead of constant Phase Change Temperature and the deviation between the results of these two is presented. The numerical analysis has been carried out by using enthalpy method and the results are verified with the experimental data. The experiments have been done by visualization technique without disturbing the actual process of melting. Three distinct stages of melting process have been identified as revealed by visualization studies. Results indicate that the melting process is chiefly governed by the magnitude of the Stefan number, Ste, Phase Change Temperature range and the capsule radius. The analysis shows that the agreement between analytical and experimental results is significantly improved when the results are obtained considering Phase Change Temperature range and the natural convection in the liquid Phase instead of considering the process to be conduction dominated only.
Yanfeng Liu - One of the best experts on this subject based on the ideXlab platform.
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Preparation and characterizations of a novel Temperature-tuned Phase Change material based on sodium acetate trihydrate for improved performance of heat pump systems
Renewable Energy, 2020Co-Authors: Li Minqi, Xiaoqing Zhou, Dengjia Wang, Zhongqi Lin, Yongjun Sun, Yanfeng LiuAbstract:Abstract Application of latent heat thermal energy storage unit is regarded as an effective method to improve the coefficient of performance of hot water heat pump systems (HWHPS). With consideration of energy efficiency and domestic hot water usage, Phase Change materials with a melting Temperature range of 45–48 °C are suitable for practical applications. The most commonly used PCMs, paraffin-based materials, are costly and have low latent heat density, which restrains their applications. This study therefore aims to prepare a novel sodium acetate trihydrate based composite PCM with suitable Phase Change Temperature and cost-effectiveness for HWHPs. A series of SAT-based composites with varying mass fraction of potassium chloride (KCl), urea, disodium phosphate dodecahydrate (DSP) and carboxyl methyl cellulose (CMC) were prepared. Their thermophysical properties and stability were investigated by freezing-melting cycling tests, differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD). The experimental results indicated that the optimized SAT-based CPCM with 8 wt% KCl, 3 wt% urea, 6 wt% CMC and 1.5 wt% DSP displayed a favorable Phase Change Temperature of 47.8 °C and a higher latent heat of 242.0 kJ/kg. Meanwhile, the results demonstrated that it has extraordinary thermal cycling performance, negligible vibration in Phase Change Temperature and latent heat, and good stability in chemical properties.
Xiao-qing Yang - One of the best experts on this subject based on the ideXlab platform.
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Series of solid-solid Phase Change materials with ultra-high thermal stability and controllable Phase Change Temperature: kilogram-leveled preparation and application investigation
Journal of Energy Storage, 2021Co-Authors: Changren Xiao, Shengtian Zhu, Guoqing Zhang, Xiao-qing YangAbstract:Abstract Phase Change materials (PCMs) have shown great performance in the fields of thermal energy storage and thermal management due to their passive yet high-efficient Temperature control and thermal energy storage properties. However, conventional physically-blended composite PCMs remain problematic, because the leakage and shape deformation phenomena cannot be ignored in engineering applications with kilogram-leveled usage. Here we develop a methodology to prepare a series of solid-solid PCMs (SSPCMs) with great thermal stability and controllable Phase Change Temperature (PCT) via free radical polymerizations. The simplest one-pot synthesis strategy allows the kilogram-leveled preparation for engineering demands. The obtained novel SSPCMs with 3-dimensional main chain and alkyl side-chain demonstrate excellent thermal stability that can withstand the heat-erosion up to 250°C without any leakage or deformation. Furthermore, the PCT region of the SSPCMs can be easily tailored in a wide range from 9.7 to 65.3°C by carefully selecting the alkyl acrylate monomers with different carbon atoms on the ester group. After simply incorporating with expanded graphite (EG), the resultant EG/SSPCMs with well-defined PCT region present excellent performance in various applications, including building energy conservation, battery thermal management and waste heat recovery. Profiting from the controllable PCT coupled with the great thermal stability, we believe that this series of SSPCMs would demonstrate huge potentials in more expanded industrial fields by further tailoring their PCT to a wider range.