Study of the usability of sinusoidal function heat flux based on enthalpy-porosity technique for PCM-related applications

A 2D-symmetric numerical study of a new design of Nano-Enhanced Phase change material (NEPCM)-filled enclosure is presented in this paper. The enclosure is equipped with an inner tube allowing the circulation of the heat transfer fluid (HTF); n-Octadecane is chosen as phase change material (PCM). Comsol-Multiphysics commercial code was used to solve the governing equations. This study has been performed to examine the heat distribution and melting rate under the influence of the inner-tube position and the concentration of the nanoparticles dispersed in the PCM. The inner tube was located at three different vertical positions and the nanoparticle concentration was varied from 0 to 0.06. The results revealed that both heat transfer/melting rates are improved when the inner tube is located at the bottom region of the enclosure and by increasing the concentration of the nanoparticles. The addition of the nanoparticles enhances the heat transfer due to the considerable increase in conductivity. On the other hand, by placing the tube in the bottom area of the enclosure, the liquid PCM gets a wider space, allowing the intensification of the natural convection.

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“…where D is the smoothed Delta Dirac function: D = e (−(T−T m ) 2 /∆T 2 ) / ∆T √ π [8,29]. The thermal conductivity of the NEPCM:…”

Section: Mathematical Modelmentioning

confidence: 99%

“…The fins increased the surface of heat exchange and reduced the convective flow of the movement of the liquid PCM, causing enhancement of the performance of the solidification process. Actually, the convective flow is an undesirable factor during the solidification process [8].…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Impact of the Heat Source Position on Melting of a Nano-Enhanced Phase Change Material

et al. 2021

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“…They also discovered that positioning the heat transfer fluid tube at the bottom and increasing the Stefan number to 0.15 increased heat transfer and melting rates by 28% in a novel PCM capsule configuration 16 . Moreover, their two‐dimensional (2D) numerical simulation demonstrated that variable heat flux conditions reduced melting time in a square cavity containing PCM, suggesting potential applications in thermal energy storage 17 . Another study examined the thermal performance of roofs with and without PCM in Northeast China, finding that PCM roofs showed a significant delay in the average temperature peak of the base layer compared with conventional roofs.…”

Section: Introductionmentioning

confidence: 98%

“…16 Moreover, their two-dimensional (2D) numerical simulation demonstrated that variable heat flux conditions reduced melting time in a square cavity containing PCM, suggesting potential applications in thermal energy storage. 17 Another study examined the thermal performance of roofs with and without PCM in Northeast China, finding that PCM roofs showed a significant delay in the average temperature peak of the base layer compared with conventional roofs. Various factors including transition temperature, roof slope, PCM layer thickness, and absorption coefficients of external roof surface were found to influence this delay.…”

Section: Introductionmentioning

confidence: 99%

Improved heating floor thermal performance by adding PCM microcapsules enhanced by single and hybrid nanoparticles

et al. 2023

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A heating floor is a low‐temperature emitter consisting of pipelines in which a fluid circulates between 35°C and 45°C. To ensure energy efficiency, occupant comfort, and building material durability, proper heat management is crucial in buildings. By using phase change materials (PCMs) in building envelopes, the indoor temperature can be regulated through the storage and release of thermal energy, which reduces energy consumption and enhances occupant comfort. In this study, we evaluated numerically a heating floor that incorporates a PCM enhanced by nanoparticles (NePCM). The aim of the numerical analysis is to assess the impact of the addition of single and hybrid nanoparticles in different proportions to the PCM layer on the thermal performance of the PCM‐based floor. Therefore, two main objectives are defined. The primary is to take advantage of the storage capacity of a PCM layer by integrating it into the ground; second, to evaluate the hot water temperature levels effect on the floor's performance. Additionally, we address the low thermal conductivity of PCM by enhancing PCM microcapsules with single and hybrid nanoparticles and comparing them to pure PCM. The numerical results obtained show that positioning the PCM microcapsules above the heating tubes (upper position) provides an optimum improvement in thermal performance. Moreover, the addition of hybrid nanoparticles within the base PCM, 1% of Cu mixed with 4% of Al2O3, allows an increase of 4°C, which relates to a reduction of 18% in the internal temperature amplitude and a phase shift of 6 h 30 min compared with the conventional heated floor in which there is no PCM.

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“…It was shown that despite the same amount of energy delivered to PCM, variable heating and cooling provides faster melting and solidification, respectively. Bouzennada et al [13] did a study on a two-dimensional simulation of the melting/solidification process of a phase change material (PCM) in a square cavity. The size is 5 × 5 cm 2 and all cavity's walls are thermally insulated, except for the left wall on which a sine function heat flux was imposed,…”

Section: Introductionmentioning

confidence: 99%

Thermal Analysis of Solid/Liquid Phase Change in a Cavity with One Wall at Periodic Temperature

2021

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In this study, heat transfer in a square cavity filled with a Phase Change Material (PCM) under a sinusoidal wall temperature during solidification and melting is analyzed. All surfaces of the cavity are insulated except one surface, which is under the sinusoidal temperature change. The governing equations and boundary conditions are made dimensionless to reduce the number of governing parameters into two as dimensionless frequency and Stefan number. The governing equations were solved numerically by using Finite Volume Method for a wide range of Stefan number (0.1 < Ste < 1.0) and dimensionless frequency (0.23 < < 2.04). Based on the obtained results, a chart in terms of Stefan number and dimensionless frequency is obtained to divide the heat transfer process in the cavity into three regions as uncompleted, completed, and overheated phase-change processes. For the uncompleted process, some parts of the cavity are inactive, and no phase change occurs in those parts of the cavity during the melting and freezing process. For the overheated phase change, the temperature of the cavity highly increases (or decreases), causing the sensible heat storage to compete with latent thermal storage. In the completed process, almost all thermal storage is done by the utilization of latent heat. The suggested graph helps thermal designers to avoid wrong designs and predict the type of thermal storage (sensible or latent) in the cavity without doing any computations.

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Study of the usability of sinusoidal function heat flux based on enthalpy-porosity technique for PCM-related applications

Cited by 16 publications

References 35 publications

Numerical Simulation of the Impact of the Heat Source Position on Melting of a Nano-Enhanced Phase Change Material

Numerical Simulation of the Impact of the Heat Source Position on Melting of a Nano-Enhanced Phase Change Material

Improved heating floor thermal performance by adding PCM microcapsules enhanced by single and hybrid nanoparticles

Thermal Analysis of Solid/Liquid Phase Change in a Cavity with One Wall at Periodic Temperature

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