Enhancing Thermal Performance in Phase Change Material through Nanoparticles and Magnetic Field in an Octagonal Cavity with Plus-Shaped Fins

ABSTRACTMixed heat transfer, commonly encountered in engineering applications, has led to a strong focus on maximizing heat transmission rates. This study explores heat transfer enhancement within a magnetohydrodynamic (MHD) double lid‐driven octagonal cavity. The cavity is filled with porous media and loaded with nano‐encapsulated phase change material (NE‐PCM), subjected to a uniform magnetic field. The Galerkin finite element method (GFEM) is employed to solve the governing equations. Key factors investigated include lid speed (Reynolds number, Re = 1–500), wall movement directions, magnetic field intensity (Hartmann number, Ha = 0–100), and cavity porosity (Darcy number, Da = 10−5–10−2) and their effects on heat transmission rates. The numerical method was validated by comparing results with well‐documented data from the literature. The findings reveal that higher Re and Da values significantly enhance heat transfer rates, while higher Ha values reduce heat transfer rates. Specifically, at the highest Re, increasing Da from 10−5 to 10−2 enhanced the averaged Nusselt number (Nu) by 165%, while increasing Ha from 0 to 100 decreased it by 16%. Additionally, moving both walls in the same direction improved the average Nu by 350% compared to opposing wall movement. The study also found that increasing NE‐PCM concentration had a minimal impact on heat transfer efficiency, while reducing chamber permeability hindered suspension movement, thereby reducing heat transfer between the hot and cold surfaces.

The literature showed many studies that evaluated single or multiple Phase change materials (PCMs) layers in passive, active, or in hybrid configurations for building applications. However, little attention has been given to evaluating the energy performance of buildings when PCMs are used together with other passive design strategies. In this work, the energy performance of an office building in a typical arid Saharan climate is simulated using EnergyPlus when a PCMs-embedded envelope is implemented. The office building was analyzed without/with PCMs using various thicknesses. Results indicated that the annual electrical energy for heating, ventilation and air conditioning (HVAC) could be reduced between 3.54% and 6.18%, depending on the PCM thickness. The performance of the office building, including PCMs, was then simulated using two practical architectural design strategies, namely windows-to-wall ratio (WWR) and rezoning of the interior spaces. Outcomes revealed that the annual energy consumption for HVAC can be reduced from 10% to 15.5% and from 6.1% and 8.54% when WWR is reduced by half to three-quarters, and the perimeter zones are enlarged by one-third to two-thirds of the original space area, respectively. By combining both architectural design strategies and PCM, the annual electrical HVAC energy can be reduced between 12.08% and 15.69%, depending on the design configuration and PCM thickness. This design option provides additional benefits also since it reduces the vulnerability of increasing the lighting and fuel gas heating energy because more perimeter zones are exposed to daylighting and solar radiation, respectively.

A cross-scale ‘material-component-system’ framework for transition towards zero-carbon buildings and districts with low, medium and high-temperature phase change materials

Evaluating the passive and free cooling application methods of phase change materials in residential buildings: A comparative study

Charging process of a partially heated trapezoidal thermal energy storage filled by nano-enhanced PCM using controlable uniform magnetic field

Thermal management of electronic equipment is the primary concern in the electronic industry. Miniaturization and high power density of modern electronic components in the energy systems and electronic devices with high power density demanded compact heat exchangers with large heat dissipating capacity. Microchannel heat sinks (MCHS) are the most suitable heat exchanging devices for electronic cooling applications with high compactness. The heat transfer enhancement of the microchannel heat sinks (MCHS) is the most focused research area. Huge research has been done on the thermal and hydraulic performance enhancement of the microchannel heat sinks. This chapter’s focus is on advanced heat transfer enhancement methods used in the recent studies for the MCHS. The present chapter gives information about the performance enhancement MCHS with geometry modifications, Jet impingement, Phase changing materials (PCM), Nanofluids as a working fluid, Flow boiling, slug flow, and magneto-hydrodynamics (MHD).

PurposeMultiple encapsulated phase change materials (PCMs) are used in a wide range of applications, including convective drying, electronic cooling, waste heat recovery and air conditioning. Therefore, it is important to understand the performance of multiple PCMs in channels with flow separation and develop methods to increase their effectiveness. The aim of the study is to analyze the phase transition dynamics of multiple encapsulated PCMs mounted in a U-shaped tube under inclined magnetic field by using ternary nanofluid.Design/methodology/approachThe PCMs used in the upper horizontal channel, vertical channel and lower horizontal channel are denoted by M1, M2 and M3. Magnetic field is uniform and inclined while finite element method is used as the solution technique. Triple encapsulated-PCM system study is carried out taking into account different values of Reynolds number (Re, ranges from 300 to 1,000), Hartmann number (Ha ranges from 0 and 60), magnetic field inclination (between 0 and 90) and solid volume fraction of ternary nanofluid (between 0 and 0.03). The dynamic response of the liquid fraction is estimated for each PCM with varying Re, Ha and t using an artificial neural network.FindingsIt is observed that for PCMs M2 and M3, the influence of Re on the phase transition is more effective. For M2 and M3, entire transition time (t-F) lowers by approximately 47% and 47.5% when Re is increased to its maximum value, whereas it only falls by 10% for M1. The dynamic characteristics of the phase transition are impacted by imposing MGF and varying its strength and inclination. When Ha is raised from Ha = 0 to Ha = 50, the t-F for PCM-M2 (PCM-M3) falls (increases) by around 30% (29%). For PCMs M1, M2 and M3, the phase transition process accelerates by around 20%, 30% and 28% when the solid volume fraction is increased to its maximum value.Originality/valueOutcomes of this research is useful for understanding the phase change behavior of multiple PCMs in separated flow and using various methods such as nano-enhanced magnetic field to improve their effectiveness. Research outputs are beneficial for initial design and optimization of using multiple PCMs in diverse energy system technologies, including solar power, waste heat recovery, air conditioning, thermal management and drying.

Enhancing thermal performance and optimization strategies of PCM-integrated slab-finned two-fluid heat exchangers for sustainable thermal management

BackgroundSteering-shaped obstacles are extensively used in various thermal engineering applications, including heat exchangers, transformers, semiconductors, microelectronics, chemical sensors, air-cooled engines, gas turbines, automotive radiators, and hydrogen fuel cells.AimsThe main goal of this study was to examine how key dimensionless parameters—such as the Reynolds number (Re), Richardson number (Ri), Hartmann number (Ha), Nusselt number (Nu), Bejan number (Be), and magnetic field angle (γ)—affect the heat transfer, fluid flow, and entropy generation in a hybrid nanofluid (TiO2−Cu−H2O) system. A mixed convection flow is analyzed inside a hexagonal cavity containing a heated steering-shaped obstacle. The cavity has two moving walls that drive the flow, whereas a magnetic field is applied at an angle. The focus is to reduce entropy generation and enhance thermal performance, which is important for improving the efficiency of advanced cooling systems.Method and validationsThe governing equations and boundary conditions are solved using the Galerkin weighted residual finite element method, with extensive validation against existing results to ensure the accuracy of the findings.ParametersIn the study, we investigate a range of parameters: nanoparticle concentration (φ) varying from 1% to 5%, Re from 1 to 300, Ha from 0 to 60, Ri from 0.1 to 10, and γ ranging from 0° to 90°.ResultsIn the study, we show that lid-driven motion of the top and bottom walls, along with a steering-shaped heated obstacle, enhances heat transfer (HT) and reduces entropy generation(Egen). Thermal performance improves with increasing Ri and Re but decreases with increasing Ha. For fixed Re = 300, at the highest magnetic field strength (Ha = 60), the HT rate reaches its minimum, exhibiting a 22.41% decrease relative to the no magnetic-field condition (Ha = 0). An increase in the Ri number leads to a 68.76% enhancement in thermal performance. At a fixed Ri=10, increasing the Re number from 1 to 300 leads to a 263.83% enhancement in thermal performance. The addition of TiO2−Cu−H2O hybrid nanofluid (HNF) further enhances thermal performance.ConclusionIn the study, we reveal that mixed-convection (MC) HNF and heated steering-shaped obstacles play a significant role in enhancing HT and reducing Eavg within the cavity.

Enhanced thermal performance of a thermoelectric generator with phase change materials

Thermal performance enhancement with solidification effect of nickel foam and MXene nanoenhanced PCM composite based thermal energy storages

In this study, natural convection of CuO–water nanofluid in a square cavity with a conductive partition and a phase change material (PCM) attached to its vertical wall is numerically analyzed under the effect of an uniform inclined magnetic field by using finite element method. Effects of various pertinent parameters such as Rayleigh number (between $$10^5$$ and $$10^6$$ ), Hartmann number (between 0 and 100), magnetic inclination angle (between $$0^{\circ}$$ and $$90^{\circ}$$ ), PCM height (between 0.2H and 0.8H), PCM length (between 0.1H and 0.8H), thermal conductivity ratio (between 0.1 and 100) and solid nanoparticle volume fraction (between 0 and 0.04) on the fluid flow and thermal characteristics were numerically analyzed. It was observed that when magnetic field is imposed, more reduction in average Nusselt number for water is obtained as compared to nanofluid which is $$31.81\%$$ for the nanofluid at the highest particle volume fraction. The average heat transfer augments with magnetic inclination angle, but it is less than $$5\%$$ . When the height of the PCM is increased which is from 0.2H to 0.8H, local and average Nusselt number reduced which is $$42.14\%$$ . However, the length of the PCM is not significant on the heat transfer enhancement. When the conductivity ratio of the PCM to the base fluid within the cavity is increased from 0.1 to 10, $$29.5\%$$ of the average Nusselt number enhancement is achieved.

Thermal management and performance enhancement of domestic refrigerators and freezers via phase change materials: A review

Numerical study of the effect of graphene nanoparticles in calcium chloride hexahydrate -based phase change material on melting and freezing time in a circular cavity with a triangular obstacle

The scheme of incompressible smoothed particle hydrodynamics (ISPH) method is developed to solve the time-conformable systems that control the double diffusion of nanoparticle-enhanced phase change materials (NEPCM) inside two circular cylinders saturated by a porous medium. The use of the time-conformable operator in the ISPH approach for addressing the double diffusion of NEPCM in a new domain is what distinguishes this work. This investigation revealed a comprehensive rate of change that impacts the quickening and slowdown of the monotonicity for the nonlinear systems. The physical parameters are time-conformable operator α , time parameter τ , nanoparticles parameter ϕ , Hartmann number Ha , thermal radiation parameter Rd , Darcy parameter Da , Rayleigh number Ra , and fusion temperature θ f . The principal outcomes of the numerical simulations revealed that the nanofluid flow is slowing down by an augmentation in ϕ , Ha , and Rd . The Rayleigh number is working well in enhancing the nanofluid flow and thermosolutal convection within the two circular cylinders. As a result, variable values of Ra are affecting the phase change material. The fusion temperature parameter controls the position/intensity of the phase change material within the two circular cylinders. Besides, the numerical results indicate the significance of α on the transition process of reaching the steady state. The thermosolutal convection and nanofluid speed are varied with the changes on the time-conformable derivative.