Numerical study of the melting of nano-enhanced phase change material in a square cavity

Nano-enhanced phase change materials (PCMs) have attracted increasing attention to address one of the key barriers (i.e. low thermal conductivity) to the wide adoption of PCMs in many industrial applications. This paper discusses the generic problem and key issues associated with appropriately using this new class of materials in buildings for effective thermal management and improved energy performance. An overview on major recent development and application of nano-enhanced PCMs as thermal energy storage media is provided. A case study based on a PCM ceiling ventilation system integrated with solar photovoltaic thermal (PVT) collectors is then performed to evaluate the potential benefits due to the dispersion of copper nanoparticles into the PCM base fluid of RT24. The results showed that this nano-enhanced PCM has higher melting and solidification rates than that of the pure PCM. Compared to the use of the pure PCM, 8.3% more heat was charged in and 25.1% more heat was discharged from the nano-enhanced PCM under the three winter test days. More research is needed to understand the fundamental mechanisms behind the PCM thermal conductivity enhancement through the dispersion of nanometer-sized materials and to investigate how these mechanisms drive building performance enhancement. Abstract: Nano-enhanced phase change materials (PCMs) have attracted increasing attention to address one of the key barriers (i.e. low thermal conductivity) to the wide adoption of PCMs in many industrial applications. This paper discusses the generic problem and key issues associated with appropriately using this new class of materials in buildings for effective thermal management and improved energy performance. An overview on major recent development and application of nano-enhanced PCMs as thermal energy storage media is provided. A case study based on a PCM ceiling ventilation system integrated with solar photovoltaic thermal (PVT) collectors is then performed to evaluate the potential benefits due to the dispersion of copper nanoparticles into the PCM base fluid of RT24. The results showed that this nano-enhanced PCM has higher melting and solidification rates than that of the pure PCM. Compared to the use of the pure PCM, 8.3% more heat was charged in and 25.1% more heat was discharged from the nano-enhanced PCM under the three winter test days. More research is needed to understand the fundamental mechanisms behind the PCM thermal conductivity enhancement through the dispersion of nanometer-sized materials and to investigate how these mechanisms drive building performance enhancement.

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“…The melting of the nano-enhanced PCMs in a square cavity was studied in [86,87]. The SIMPLE method was used to solve the governing equations.…”

Section: Numerical and Experimental Investigation On Thermodynamic Bementioning

confidence: 99%

Nano-enhanced phase change materials for improved building performance

Lin

Sohel

2016

Renewable and Sustainable Energy Reviews

158

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“…The subscript PCM indicates the physical characteristic of the PCM or Nano-PCM, while the subscript foam indicates the physical characteristic of the metal foam. To calculate the values of the proprieties of the Nano-PCM, the following relations [22] are used:…”

Section: Physical Modelmentioning

confidence: 99%

Numerical investigation on Nano-PCM in aluminum foam in latent thermal energy storages

Buonomo¹,

Ercole²,

Manca³

et al. 2018

MMC_B

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Thermal storage system (TES) with phase change material (PCM) is an important device to store thermal energy. It works such a thermal buffer to reconcile the supply energy with the energy demand. It has a wide application field especially for solar thermal energy storage. The main drawback is the low value of thermal conductivity of the PCM making the system useless for the thermal engineering applications. A way to resolve this problem is to combine the PCM with a highly conductive material like metal foam and/or nanoparticles. In this paper a numerical investigation on the metal foam effects into the latent heat thermal energy storage system, based on a phase change material with nanoparticles (Nano-PCM), is accomplished. The modelled TES is a typical 70L water tank filled up with Nano-PCM with pipes to transfer thermal energy from a fluid to the Nano-PCM. The PCM is a pure paraffin wax and the nanoparticles are in aluminum oxide. The metal foam is made of aluminum with assigned values of porosity. The enthalpyporosity theory is employed to simulate the phase change of the Nano-PCM and the metal foam is modelled as a porous media. Numerical simulations are carried out using the Ansys-Fluent code. The results are shown in term of melting time, temperature at varying of time and total amount of stored energy. Keywords:thermal energy storage, Nano-PCM, foams Ren et al. [17] have numerically investigate the melting process of the PCM of a TES system with nanoparticles and Modelling, Measurement and Control B

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“…In this term 5 <C 1 is a tiny constant to avoid division by zero without physical meaning, and C is a constant for the mushy region that depends on the PCM. We set the Darcy coefficient C = 1.6 x 10 6 kgm~3s, in compliance with previous works ( [10]). When a control volume is completely liquid (/; = 1) this term is null, like in a single phase fluid, when it is completely solid (/; = 0) the term diverges and the velocity of the liquid becomes null, like in a solid.…”

Section: Momentum Equationmentioning

confidence: 99%

Enhancement of heat transfer rate on phase change materials with thermocapillary flows

Madruga

Mendoza

2017

Eur. Phys. J. Spec. Top.

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We carry out simulations of the melting process on the phase change material n-octadecane in squared geometries in the presence of natural convection and including thermocapillary effects. We show how the introduction of thermocapillary effects enhances the heat transfer rate, being the effect especially relevant for small Bond numbers. Thus induction of Marangoni flows results in a useful mechanism to enhance the typical slow heat transfer rate of paraffin waxes in applications of energy storage or passive control management.

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Numerical study of the melting of nano-enhanced phase change material in a square cavity

Cited by 94 publications

References 28 publications

Nano-enhanced phase change materials for improved building performance

Nano-enhanced phase change materials for improved building performance

Numerical investigation on Nano-PCM in aluminum foam in latent thermal energy storages

Enhancement of heat transfer rate on phase change materials with thermocapillary flows

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