Journal of Energy Storage
·
2024
·
IF 8.9
Zijian He,Hongting Ma,Shilei Lu
In order to effectively address the mismatch between thermal energy supply and demand in buildings, latent heat storage (LHS) based on phase change material (PCM) stands out as a key technology. While hydrated salt has emerged as a promising PCM, it encounters common issues such as substantial supercooling, phase separation, and low thermal conductivity , hindering its development. To mitigate these limitations, this study focused on modifying Ba(OH) 2 ·8H 2 O by incorporating various nucleating agents and thickening agents to reduce supercooling, enhancing the composite PCM's thermal properties by introducing expanded graphite (EG) to elevate thermal conductivity . Subsequently, the thermal stability of the PCM was evaluated through accelerated thermal cycling tests, encompassing the assessment of critical thermal parameters, including supercooling degree, enthalpy, and thermal conductivity of the composite PCM. Experimental findings unveiled the effectiveness of incorporating 2 wt% BaCl 2 ·2H 2 O and 1 wt% CMC to Ba(OH) 2 ·8H 2 O, effectively diminishing the supercooling degree from 14 °C to 1.42 °C. Further integration of 3.5 wt% EG led to a substantial decrease in the supercooling degree to 0.24 °C. Simultaneously, the addition of EG resulted in an improvement in thermal conductivity , elevating it from 0.62 W/(m·K) to 1.03 W/(m·K), while the enthalpy decreased from 283.68 J/g to 252.81 J/g. Notably, the composite PCM exhibited notable thermal reliability with a latent heat drop of 15.9 % following 1000 accelerated cycles of testing. Moreover, the composite PCM demonstrated superior thermal storage density, measuring at 2.36 times that of traditional paraffin wax , yet with a thermal storage cost merely a quarter of paraffin wax, rendering it more favorable for extensive deployment in building energy systems .
研究领域:
能源工程
·
建筑材料
✓ 已验证
产品关联
DOI
高影响因子
ENERGY CONVERSION AND MANAGEMENT
·
2017
·
IF 5.589
Shile Shen,Shujuan Tan,Sai Wu,Cheng Guo,Juan Liang,Qian Yang,Guoyue Xu,Jie Deng
Three different methods, acid oxidation, mechanochemical process and ball milling, were used to modify multi-walled carbon nanotubes (MWCNTs). The MWCNTs were dispersed into erythritol (Ery) to prepare composite phase change materials (PCMs). The effects of the MWCNTs on the thermal properties of erythritol-based composite PCMs were studied experimentally. FT-IR and XPS spectroscopy show that hydroxyl groups and carboxylic groups were generated on the surface of the MWCNTs after modification. The pretreatment of MWCNTs can improve their dispersibility in erythritol. When the mass fraction of MWCNTs was 1%, the thermal conductivity of Ery was increased obviously from 0.1956 W/(m·K) to 0.9779 W/(m·K). Besides, the MWCNTs could help improve the supercooling and solidification enthalpy of erythritol significantly. When the mass fraction of A-MWCNTs was only 0.5%, the freezing temperature of PCMs increased from 18.8 °C to 58.15 °C and the solidification enthalpy increased 50 J/g. After 10 heating and cooling cycles, the Ery/A-MWCNTs composites show a very good thermal cycling stability.
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
SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2021
·
IF 7.267
Liu Liu,Jianlei Niu,Jian-Yong Wu
This study was to develop stable phase change material (PCM)-water nano-emulsions with low supercooling and low viscosity using two-surfactant mixtures by the phase inversion temperature (PIT) method. The PCM agent n-hexadecane was mixed with Brij L4 as the primary surfactant and polyethylene-block-poly(ethylene glycol) (PE- b -PEG), Tween 60 or Tween 80 as a co-surfactant to form stable nano-emulsions. The results showed that the droplet size , viscosity and PIT point as well as the stability of PCM nano-emulsions were strongly dependent on the combination, mass ratio and total concentration of the two surfactants. In 25% (w/w) PCM nano-emulsions, an optimum formulation was the surfactant combination of Brij L4 and Tween 60 at 6:4 mass ratio, mixed with PCM at 11:20 mass ratio. The corresponding nano-emulsion had a high stability, a small droplet size of 60 nm and desirable Newtonian fluid behaviour with a relatively low viscosity of 50 mPa s. The addition of n-octacosane as a nucleating agent was effective to reduce the emulsion supercooling, though the supercooling degree was notably increased after multiple thermal cycles. The optimized 25% PCM nano-emulsion with 2% (w/w) n-octadecane showed an excellent stability over 120 days and 300 thermal cycles with a droplet size below 80 nm, a supercooling degree of ~5 °C and a latent heat of ~50 J/g, which was very promising for further development and application as a cooling storage medium.
研究领域:
材料科学
·
能源工程
·
化学工程
✓ 已验证
DOI
高影响因子
Journal of Energy Storage
·
2024
·
IF 8.9
Ting Wang,Wei Cui,Xiangxuan Li,Ting Ma,Qiuwang Wang
Due to their high heat storage density, low cost, and non-inflammability, hydrated salts have significant potential for application in thermal energy storage for buildings. Hydrated salts, however, have a few drawbacks, including high supercooling degree, unstable shape, and phase separation. In general, materials such as graphite, aerogel, and foam metal are commonly used to provide support for hydrated salts in order to mitigate or eliminate their drawbacks. While these currently used supporting materials have expensive and complicated production procedures. In this study, we developed bagasse biomass-derived carbon (BBC) materials to obtain easily accessible, cost-effective, and environmentally friendly support materials. Using the high-temperature carbonization method, the bagasse made from biological waste displayed a highly oriented and stacked lamellar structure. This not only significantly lowered the cost but also made the storage of hydrated salts easier. A straightforward vacuum impregnation technique was used to create SSD-SC/BBC phase change composites (PCCs). In comparison to sodium sulfate decahydrate (SSD), the developed SSD-SC/BBC9 PCCs exhibited a higher thermal storage capacity of 161.5 J/g, along with an exceptionally low supercooling degree. They also demonstrated the higher thermal conductivity of 1.79 W·m −1 ·K −1 , improved thermal reliability, and enhanced solar-thermal energy conversion ability. Compared to other support materials, the economic analysis using static and dynamic payback periods demonstrates that the utilization of biomass-derived carbon as a support material for phase change materials (PCMs) is cost-effective, with lower preparation costs and a shorter payback period. A simple, affordable, and environmentally friendly method for utilizing hydrated salts in thermal energy storage for buildings is provided by SSD-SC/BBC9 PCCs.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED THERMAL ENGINEERING
·
2017
·
IF 3.444
Xue-Feng Shao,Song-Ping Mo,Ying Chen,Tao Yin,Zhi Yang,Li-Si Jia,Zheng-Dong Cheng
The solidification behavior of hybrid nanofluids containing TiO 2 nanotubes (TiNTs) and nanoplatelets (TiNPs) was investigated in 10 freeze–melt cycles and the results were compared with those of individual TiNT and TiNP nanofluids. Hybrid TiO 2 nanofluids showed lower supercooling degrees because of larger surface area exposed to water, and shorter freezing time as a result of higher thermal conductivities, compared with individual TiNT and TiNP nanofluids. A maximum reduction of 5.27 ± 0.2 °C in supercooling degree and 56.42% in freezing time were achieved for hybrid nanofluids containing 25% and 50% TiNPs, respectively. The supercooling degree and freezing time of hybrid nanofluids showed less of an increase across 10 freeze–melt cycles as they have better dispersion stability compared with individual nanofluids. Evidently, the smallest increase of 0.68 ± 0.2 °C in supercooling degree and 29.85% in freezing time was achieved in 0.1 wt.% hybrid nanofluid compared with 2.02 ± 0.2 °C and 130.37% for individual TiNT nanofluids and 3.98 ± 0.2 °C and 101.08% for individual TiNP nanofluids. These promising performances highlight the outstanding thermal energy storage applications of hybrid nanofluids.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2021
·Vol. 14
·期 19
·5481
·
IF 3.623
Songping Mo,Yuanhong Li,Shaofei Shan,Lisi Jia,Ying Chen
Sugar alcohols are phase-change materials with various advantages but may suffer from leakage during applications. In this study, inositol nanocapsules were synthesized at various conditions, including the amount of precursors and the time for adding the precursors. The effects of synthesis conditions on the properties of the nanocapsules were studied. The morphology, chemical composition, microstructure, phase-change characteristics and size distribution of the nanocapsules were investigated by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), differential scanning calorimeter (DSC) and a zeta potential analyzer. The results confirm that inositol was well-encapsulated by an SiO2shell. The shell thickness increased, while the supercooling degree of the nanocapsules decreased with increasing time for adding the precursors. In order to obtain nanocapsules with good morphology and phase-change characteristics, the time for adding the precursors should increase with the amount of precursors. The nanocapsules with the best properties exhibited high melting enthalpy, encapsulation ratio and energy storage efficiency of 216.0 kJ/kg, 83.1% and 82.1%, respectively. The size of the nanocapsules was remarkably affected by the triethoxysilane (TES) amount.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
APPLIED THERMAL ENGINEERING
·
2022
·
IF 6.465
Zhigao Sun,Zhifan Chen,Mingrui Liu
In order to improve the thermal conductivity of organic phase change materials and overcome the shortcomings of large supercooling degree and phase separation of inorganic phase change materials, the composites of sodium acetate, stearic acid and octadecyl alcohol as phase change materials were prepared by melt blending method, where disodium hydrogen phosphate dodecahydrate was used as nucleating agent and carboxymethyl cellulose as thickener in this work. XRD, DSC and T-history techniques were used to analyze the composite phase change materials. Sodium acetate, stearic acid and octadecyl alcohol are physically blended in the ternary composite phase change materials. Sodium acetate improves the thermal conductivity and latent heat of the eutectic mixtures of stearic acid and octadecyl alcohol, where the thermal conductivity and latent heat of the eutectic mixtures of stearic acid and octadecyl alcohol is increased by 384 % and 28%, respectively. Heat conduction and natural convection act together, but natural convection plays an important role in the melting process. While heat conduction plays an important part in the discharging process. Due to natural convection, the charging time of the composite phase change materials is less than the discharging time.
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
RSC Advances
·
2014
·Vol. 4
·期 69
·36584-36590
·
IF 3.708
Qianqiu Tang,Jun Sun,Shuangmin Yu,Gengchao Wang
Improving thermal conductivity and decreasing supercooling are essential for the utilization of paraffin phase change materials (PCMs). In this work, n-octadecylamine-functionalized multi-walled carbon nanotubes (f-MWCNTs) are obtained through a simple method of carboxylation of the MWCNTs with mixed acids of H2SO4 and HNO3 and then salt-forming reaction with n-octadecylamine. The paraffin/f-MWCNTs (paraffin/f-MWCNTs) composite PCMs are fabricated by mixing paraffin with f-MWCNTs under ultrasonication at 70 °C. It is found that the f-MWCNTs are homogenously dispersed in a toluene or paraffin matrix due to the existence of long chain alkanes in f-MWCNTs. As a result, the thermal conductivity and heat transfer of the paraffin/f-MWCNTs composite PCMs are significantly enhanced. Moreover, differential scanning calorimetry (DSC) analysis indicates that the incorporation of f-MWCNTs reduces the supercooling of paraffin, mainly due to the well-dispersed f-MWCNTs serving as nuclei to promote the heterogeneous nucleation and crystallization process of paraffin.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
Asia-Pacific Journal of Chemical Engineering
·
2020
·Vol. 16
·期 1
·e2563
·
IF 1.06
Mengyao Lu,Xuelai Zhang,Jun Ji,Yongyichuan Zhang
In order to solve the problems of high supercooling, poor thermal conductivity and phase separation after repeated use of Na 2 S 2 O 3 ·5H 2 O with additives. In this paper, Na 2 S 2 O 3 ·5H 2 O is used as the matrix phase change material, and 1% sodium carboxymethyl cellulose, 3% SrCl 2 ·6H 2 O, and 10% expanded graphite (EG) are added to prepare the modified Na 2 S 2 O 3 ·5H 2 O composite phase change energy storage material. Based on the existing research, the effects of reducing supercooling, improving thermal conductivity, and improving stability are further optimized. The phase change temperature, supercooling degree, heat release time, phase change latent heat, and thermal conductivity of the material are tested by temperature data acquisition instrument, differential scanning calorimeter, hot disk thermal constant analyzer, and other instruments. The effect of EG on the thermal conductivity of the Na 2 S 2 O 3 ·5H 2 O composite phase change energy storage material was explored from the microstructure through a digital scanning electron microscope; Fourier transform infrared spectroscopy verified the composition of the composite phase change materials. After 200 cycles of melting and solidification, the improved composite phase change material has a phase change temperature of 43.49°C, a supercooling degree of 2.19°C, a phase change latent heat of 198.7 J/g, and a thermal conductivity of 3.42 W/m·K. Composite phase change material shows good thermal stability and provides strong support for phase change energy storage technology.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Keliang Song,Zhuoni Jiang,Fangfang He,Yongsheng Li,Zhiyu He,Yintao Li,Peng Wang,Guansong He,Wenbin Yang
Inorganic hydrated salts possess high latent heat of phase transition and are promising phase change materials (PCMs). However, the issues of supercooling, low thermal conductivity , susceptibility to leakage, and phase separation significantly impediment the practical applications of inorganic hydrated salts. In this study, it is proposed to decrease the inorganic hydrated salt supercooling degree by increasing the surface roughness of the porous material and to load the nucleating agent silver (Ag) onto polydopamine (PDA) modified melamine foam (MF) by electroless plating to obtain 3D porous Ag foams, which are then utilized as support materials. The results demonstrated that the 3D porous Ag foam compounded with barium hydroxide octahydrate (BHO) can ameliorate the shortcomings of leakage and reduce the supercooling degree in the cooling process. The composite not only exhibits high enthalpy of over 248.5 J/g and high thermal conductivity of 1.82 W·m −1 ·K −1 but also has a low supercooling degree of 0.21 ℃. Furthermore, the composites exhibited superior shape stability and thermal cycling stability. This study provides an effective method for reducing the supercooling degree of inorganic hydration salts.
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
Advanced Composites and Hybrid Materials
·
2023
·Vol. 6
·期 2
·1-13
·
IF 20.1
Lian Peng,Yan Ruihan,Wu Zhiguo,Wang Zhibin,Chen Ying,Zhang Li,Sheng Xinxin
Inorganic hydrated salt phase change materials (PCMs) have received great attention due to their capabilities to reduce building energy consumption and improve building thermal comfort. In this work, a modified PCM (DHPD-STP) with a low supercooling degree was first prepared by using disodium hydrogen phosphate dodecahydrate (Na 2 HPO 4 ·12H 2 O, DHPD) as the matrix and sodium thiosulfate pentahydrate (Na 2 S 2 O 3 ·5H 2 O, STP) as a nucleating agent. Then expanded graphite (EG) was added to DHPD-STP to afford a novel form-stable composite phase change material (CPCM). The novel CPCM obtained had a phase transition temperature (34.74 °C) appropriate for building thermal management, an excellent phase change enthalpy (184.39 J/g), and an extremely low supercooling degree (1.1 °C). The addition of EG greatly improved the form stability and cycle stability of the CPCM. Even after 200 cycles, the CPCM prepared still had a high enthalpy of phase changes (164.54 J/g). More importantly, the use of CPCM-loaded roofs effectively mitigated the variation of room temperature and improved indoor thermal comfort. The above results demonstrate the great potential of the CPCM prepared for passive building thermal management. Graphical Abstract
研究领域:
建筑材料
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2021
·Vol. 11
·期 49
·30495-30502
·
IF 3.361
Jingyi Zhang,Benwei Fu,Chengyi Song,Wen Shang,Peng Tao,Tao Deng
Ethylene glycol (EG) nanofluids have been intensively explored as one of the most promising solid–liquid phase change materials for subzero cold thermal energy storage (CTES). However, the prepared nanofluids usually suffer from a large supercooling degree, a long freezing period, reduced storage capacity and poor dispersion stability. Herein, we overcome these issues by developing stable EG nanofluids that are uniformly dispersed with low concentrations of monolayer ethanol-wetted graphene oxide nanosheets. The homogeneously dispersed monolayer sheet not only improves the thermal conductivity of the nanofluids (12.1%) but also provides the heterogeneous nucleation sites to trigger the crystal formation, thereby shortening the freezing time and reducing the supercooling degree. Compared with the base fluid, the nanofluids have reduced the supercooling degree by 87.2%, shortened the freezing time by 78.2% and maintained 98.5% of the latent heat. Moreover, the EG nanofluids have retained their initial stable homogeneous dispersion after repeated freezing/melting for 50 cycles, which ensures consistent CTES behavior during long-period operations. The facile preparation process, low loading requirement and consistent superior thermophysical properties would make the EG nanofluids loaded with monolayer graphene oxide sheets promising coolants for high-performance phase change-based CTES.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）