scholarly journals Effect of the PSSMA Content on the Heat Transfer Performances of Polyurea Nano-Encapsulated Phase Change Materials

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3157
Author(s):  
Jun-Won Kook ◽  
Kiseob Hwang ◽  
Jun-Young Lee

Polyurea nano-encapsulated phase change materials (PUA-NEPCMs) were prepared from an n-octadecane core and through the formation of amide bonds by the reaction of toluene 2,4-diisocyanate and poly(4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSMA), followed by the subsequent formation of a PUA shell using a miniemulsion system. The effects of the synthetic conditions on the thermal properties and encapsulat ion effect of the NEPCMs were systematically investigated. Differential scanning calorimetry (DSC) revealed that the melting enthalpy and encapsulation efficiency of the PUA-NEPCMs prepared under optimal conditions reached 123.00 J/g and 54.27%, respectively. Although previous results suggested that the introduction of PSSMA results in a reduced heat transfer performance for NEPCMs, DSC analysis of the prepared PUA-NEPCMs showed that increasing PSSMA contents enhanced the heat transfer performance due to a decrease in the degree of supercooling. Our results could therefore lead to further enhancements in the heat transfer performance of PUA-NEPCMs, in addition to expanding their field of application.

2020 ◽  
Vol 993 ◽  
pp. 920-926
Author(s):  
Bi Chuan Chi ◽  
Yan Yao ◽  
Su Ping Cui

The binary eutectic mixtures of fatty acid esters are promising phase change materials for energy storage application. However, the low thermal conductivity which is a common problem for organic phase change materials restricts their further and better applications. In order to solve the problem, a novel composite phase change material (CPCM) was prepared in this research by using methyl palmitate-methyl stearate (MP-MS), a typical binary eutectic mixture of fatty acid esters, as phase change material and expanded graphite (EG) as heat transfer enhancer. The heat transfer performance of MP-MS/EG CPCM was numerical simulated by finite element analysis software ABAQUS. Numerical simulation results revealed that EG could notably enhance the heat transfer performance of MP-MS eutectic mixture. The heat transfer rate and phase change reaction rate of MP-MS/EG CPCM were 14 times and 3 times that of MP-MS eutectic mixture, respectively.


Author(s):  
C. Y. Zhao ◽  
D. Zhou ◽  
Z. G. Wu

In this paper the solid/liquid phase change heat transfer in porous materials (metal foams and expanded graphite) at low and high temperatures is experimentally investigated, in an attempt to examine the feasibility of using metal foams to enhance the heat transfer capability of phase change materials for use with both the low and high temperature thermal energy storage systems. In this research, the organic commercial paraffin wax and inorganic hydrate calcium chloride hydrate salts were employed as the low-temperature materials, while the sodium nitrate is used as the high-temperature PCM in the experiment. The heat transfer characteristics of these PCMs embedded with open-cell metal foams were studied experimentally. The composites of paraffin and expanded graphite with different graphite mass ratios, namely, 3%, 6% and 9%, were also made and the heat transfer performances of these composites were tested and compared with metal foams. Overall metal foams can provide better heat transfer performance than expanded graphite due to their continuous inter-connected structures. But the porous materials can suppress the natural convection effect in liquid zone, particularly for the PCMs with low viscosities, thereby leading to the different heat transfer performance at different regimes (solid, solid/liquid and liquid regions). This implies that the porous materials don’t necessarily mean they can always enhance heat transfer in every regime.


2020 ◽  
Vol 834 ◽  
pp. 132-138
Author(s):  
Bi Chuan Chi ◽  
Yan Yao ◽  
Su Ping Cui

Methyl palmitate (MP) is a promising phase change energy storage material. It features high latent heat, suitable phase change temperature, low degree of supercooling and so on. However, like other organic phase change materials, the common problem of lower thermal conductivity makes it unable to perform better in energy storage. Expanded graphite (EG) has been proven to be high-efficiency for enhancing the thermal conductivity of organic phase change materials. MP/EG phase change composite was prepared and characterized in this research, and the heat transfer performance was numerical simulated by finite element analysis software ABAQUS. Results show that MP can be absorbed into the layered pores of EG, and the stable absorption ratio is 77%. Numerical simulation results reveal that EG can significantly enhance the heat transfer performance of MP. Moreover, EG can decrease the system temperature gradient during phase change process that makes the heat transfer and temperature distribution more uniform.


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