Experimental Study of the Thermal Properties of a Homogeneous Dispersion System of a Paraffin-based Composite Phase Change Materials

Wu, Xuehong; Gao, Maotiao; Wang, Kai; Wang, Qiangwei; Cheng, Chuanxiao; Zhu, Youjian; Zhang, Fangfang; Zhang, Qi

doi:10.1016/j.est.2021.102398

Cited by 22 publications

(8 citation statements)

References 12 publications

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“…This finding for composite SSPCM containing MWCNTs is surprising because the concentration used (0.6 wt %) is definitely above the percolation threshold (see Figure ). Possibly, the dispersion of the carbon nanotubes was not good enough to realize the potential of the filler in TC enhancement, as many authors reported the enhancement of TC for 1 wt % CNT composite PCMs, which varied within a wide range ∼6–170%. ,,− Oppositely, a significant rise of TC was observed for SSPCM containing 3.0 wt % GnPs; the TC value was equal to 0.454 W/(m•K), which is ∼40% higher than the value obtained for unfilled SSPCM. Thus, the overall effect of TC enhancement caused by both gelation and incorporation of graphene nanoparticles reached 64.5%.…”

Section: Resultsmentioning

confidence: 97%

“…Thus, the overall effect of TC enhancement caused by both gelation and incorporation of graphene nanoparticles reached 64.5%. Similarly, an increase of TC for PCMs filled with 3 wt % of GnPs is reported to vary in a range of ∼30–300% due to the differences in the dispersion state of GnP particles and their size. ,,, Note, that the estimation of TC improvement based on the results of T -history tests gave underestimated values when compared with those obtained by direct TC measurements.…”

Section: Resultsmentioning

confidence: 97%

“…The corresponding DSC thermograms of the original and thermally cycled samples also do not differ significantly. Usually, thermal properties of organic PCMs, subjected to thermal cycling remain unchanged, and up to 5% heat of fusion/crystallization decrease is considered acceptable. − In the case of HSA/Mil-PCM, only minor variations (0.2–0.3 °C) of phase transition peak temperatures were observed, whereas no heat of fusion/crystallization decrease was found. It should be mentioned that while the shapes of the crystallization peaks before and after cycling were similar, the corresponding melting peaks progressively narrowed with cycles, reflecting narrowing of the crystallites’ size distribution.…”

Section: Resultsmentioning

confidence: 99%

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Phase Change Material with Gelation Imparting Shape Stability

et al. 2022

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Blending two gelators with different chemistries (12-hydroxystearic acid and a bis-urea derivative, Millithix MT-800) was used to impart shape stability to CrodaTherm 29, a bio-based phase change material (PCM), melting/crystallizing at near-ambient temperature. The gelators immobilized the PCM by forming an interpenetrating fibrillar network. 15 wt % concentration of the gelators was found to be effective in preventing liquid PCM leakage. In order to improve the mechanical properties and thermal conductivity (TC) of the PCM, gelation of suspensions of multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GnPs) in a molten material was done at concentrations exceeding their percolation thresholds. Compared to pristine PCM, the gelled PCM containing 3.0 wt % of GnPs demonstrated a shorter crystallization time, ∼1.5-fold increase in strength, improved stability, and ∼65% increase in TC. At the same time, PCM filled with up to 0.6 wt % of MWCNTs had diminished strength and increased leakage with a slight TC improvement. Gelation of PCM did not significantly alter its thermal behavior, but it did change its crystalline morphology. The developed shape-stable PCMs may have a wide range of applications in ambient temperature solar-thermal installations, for example, temperature-controlled greenhouses, net zero-energy buildings, and water heaters.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

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Phase Change Material with Gelation Imparting Shape Stability

et al. 2022

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“…Rufuss et al 104 added TiO 2 , CuO, and graphene oxide nanoparticles to paraffin, and the TC of the three nano-PCMs was increased by 25.0%, 28.8%, and 101% respectively. Wu et al 105 added G and CNTs to paraffin using mechanical blending. It is found that when the mass fraction of GNPs is 5%, the TC of the GNPs/paraffin composite is 0.266 W/(m• K), which is 37.1% higher than that of pure paraffin, the phase transition temperature is not large, the latent heat is slightly reduced, and the performance is stable after cycling experiments.…”

Section: Role Of Additives and Comparativementioning

confidence: 99%

Comparative Analysis of Additives for Increasing Thermal Conductivity of Phase Change Materials: A Review

Zhang

et al. 2022

Energy Fuels

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The use of cold storage devices to store energy at low peaks of power usage and release it at peaks is an economic measure. It is also one of the main means to solve the imbalance between electricity shortages during the day and abundance at night. Adding cold storage balls equipped with phase change materials (PCMs) into water cold storage devices can utilize the sensible heat of water and the latent heat of PCMs for cold storage, which has a high energy storage density and can provide cold water with a suitable temperature. PCMs can be divided into organic phase change materials (OPCMs) and inorganic phase change materials (IPCMs), but both have defects. Adding additives or other materials to them to form composite phase change materials (CPCMs) can obtain suitable thermal properties. In the process of material application, some PCMs have problems of poor thermal conductivity (TC) and liquid leakage. The use of additives such as expanded graphite (EG), metal foam, and nanoparticles is a better solution to the above problems. In recent years, many scholars have researched PCMs and additives for increasing thermal conductivity (AITC). However, there is still a lack of detailed comparison among EG, metal foam, and nanoparticles. This article will introduce the PCMs used in the temperature zone (TZ) of cold storage air-conditioning systems (CSASs) and analyze their advantages, disadvantages, and improvement methods. This paper will focus on the latest research on the effect of additives such as nanoparticles, EG, and metal foam on the TC of PCMs. It will also compare the special effects of AITC in preventing supercooling, preventing phase separation, preventing leakage of liquid PCMs, and flame retarding. The future research directions of AITC will be discussed.

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“…With the dispersion of 5% GNPs in paraffin PCM, the thermal conductivity of the PCM was enhanced by 37.1% compared to the pristine PCM. Moreover, the melting rate, the freezing rate, and the thermal stability were also improved by the insertion of CNTs and GNPs [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Polyethylene Glycol and Activated Carbon Macroparticles on Thermal Conductivity of Paraffin Wax for Thermal Storage Applications

Myat

Ahmad

Pulidindi³

et al. 2022

Polymers

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Low thermal conductivity is the major obstacle for the wide range utilization of phase change materials (PCMs), especially organic PCMs, for most practical applications in thermal engineering. This study investigates the potential of enhancing the charging and discharging rates of organic PCM (RT44HC) by introducing polyethylene glycol (PEG) and activated carbon macroparticles (ACMPs). Different concentrations of PEG and ACMPs ranging from 0.3 wt% to 2 wt% were tested separately. The optimized concentrations found were used as dual reinforcements to attain the highest possible thermal conductivity. The specimens were tested for a complete charging–discharging cycle using an improvised thermal apparatus. Use of ACMP alone resulted in a minimal reduction in complete charging–discharging time due to the settlement of ACMPs at the bottom after 2–3 heating–cooling cycles. However, the addition of PEG with ACMPs exhibited a reduction in charging–discharging time due to the formation of a stable dispersion. PEG served as a stabilizing agent for ACMPs. The lowest charging–discharging time of 180 min was exhibited by specimens containing 1 wt% PEG and 0.5 wt% ACMPs which is 25% lower compared to bare PCM.

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Experimental Study of the Thermal Properties of a Homogeneous Dispersion System of a Paraffin-based Composite Phase Change Materials

Cited by 22 publications

References 12 publications

Phase Change Material with Gelation Imparting Shape Stability

Phase Change Material with Gelation Imparting Shape Stability

Comparative Analysis of Additives for Increasing Thermal Conductivity of Phase Change Materials: A Review

Effect of Polyethylene Glycol and Activated Carbon Macroparticles on Thermal Conductivity of Paraffin Wax for Thermal Storage Applications

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