Thermal performance evaluation of non-uniform fin array in a finned double-pipe latent heat storage system

Shahsavar, Amin; Goodarzi, Abbas; Mohammed, Hayder I.; Shirneshan, Alireza; Talebizadehsardari, Pouyan

doi:10.1016/j.energy.2019.116800

Cited by 135 publications

(38 citation statements)

References 57 publications

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“…The fluid flow was laminar and transient and was also considered incompressible and Newtonian. The viscous dissipation was also neglected and the no-slip boundary condition was used for the walls [45,50]. The adiabatic boundary condition was considered for the outer wall of the heat exchanger and for PCM walls at the bottom and top of the heat exchanger, which is meaningful, considering a high-quality insulation.…”

Section: Mathematical Modelingmentioning

confidence: 99%

“…For obtaining a good role of natural convection during melting, Singh et al [44] recommended a non-uniform distribution with a gradual decrease in the circular fin height, so that up to 43% charging-time saving could be achieved. However, Shahsavar et al [45] reported that homogeneous fin distribution could save melting time by around 24 percent compared to the corresponding non-uniform fin distribution. Yang et al [46] found that applying fins with irregular distributions can reduce the average temperature of PCMs by about 34% and save 63% on melting time.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Heat Transfer Enhancement in a Triple Tube Latent Heat Storage System Using Circular Fins with Inline and Staggered Arrangements

et al. 2021

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Inherent fluctuations in the availability of energy from renewables, particularly solar, remain a substantial impediment to their widespread deployment worldwide. Employing phase-change materials (PCMs) as media, saving energy for later consumption, offers a promising solution for overcoming the problem. However, the heat conductivities of most PCMs are limited, which severely limits the energy storage potential of these materials. This study suggests employing circular fins with staggered distribution to achieve improved thermal response rates of PCM in a vertical triple-tube heat exchanger involving two opposite flow streams of the heat-transfer fluid (HTF). Since heat diffusion is not the same at various portions of the PCM unit, different fin configurations, fin dimensions and HTF flow boundary conditions were explored using computational studies of melting in the PCM triple-tube system. Staggered configuration of fin distribution resulted in significant increases in the rates of PCM melting. The results indicate that the melting rate and heat charging rate could be increased by 37.2 and 59.1%, respectively, in the case of staggered distribution. Furthermore, the use of lengthy fins with smaller thickness in the vertical direction of the storage unit resulted in a better positive role of natural convection; thus, faster melting rates were achieved. With fin dimensions of 0.666 mm × 15 mm, the melting rate was found to be increased by 23.6%, when compared to the base case of 2 mm × 5 mm. Finally, it was confirmed that the values of the Reynolds number and inlet temperatures of the HTF had a significant impact on melting time savings when circular fins of staggered distribution were included.

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Section: Mathematical Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigation of Heat Transfer Enhancement in a Triple Tube Latent Heat Storage System Using Circular Fins with Inline and Staggered Arrangements

et al. 2021

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“…Because of the weak thermal conductivity of PCMs, the thermal efficiency of thermal energy storage systems (TES) suffers from low heat transfer rates. Different methods are used to enhance the thermal conductivity, such as utilizing different configurations of fins [ 5 ], changing the configuration of the geometry [ 6 , 7 , 8 ], metal foam [ 9 ], and nanotechnology [ 10 , 11 ], using multiple PCMs [ 12 ], and using the combinations of different methods [ 12 ]. LHTES systems naturally result in a compact thermal energy storage design due to the high energy density of phase change.…”

Section: Introductionmentioning

confidence: 99%

Optimum Placement of Heating Tubes in a Multi-Tube Latent Heat Thermal Energy Storage

et al. 2021

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Utilizing phase change materials in thermal energy storage systems is commonly considered as an alternative solution for the effective use of energy. This study presents numerical simulations of the charging process for a multitube latent heat thermal energy storage system. A thermal energy storage model, consisting of five tubes of heat transfer fluids, was investigated using Rubitherm phase change material (RT35) as the. The locations of the tubes were optimized by applying the Taguchi method. The thermal behavior of the unit was evaluated by considering the liquid fraction graphs, streamlines, and isotherm contours. The numerical model was first verified compared with existed experimental data from the literature. The outcomes revealed that based on the Taguchi method, the first row of the heat transfer fluid tubes should be located at the lowest possible area while the other tubes should be spread consistently in the enclosure. The charging rate changed by 76% when varying the locations of the tubes in the enclosure to the optimum point. The development of streamlines and free-convection flow circulation was found to impact the system design significantly. The Taguchi method could efficiently assign the optimum design of the system with few simulations. Accordingly, this approach gives the impression of the future design of energy storage systems.

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“…To enhance the thermal response of LHTES, various techniques have been proposed, such as the use of a finned unit to increase total surface areas [ 4 , 5 ], direct contact heat transfer [ 6 ], and the modification of materials with a porous matrix [ 7 , 8 ]. Several studies have demonstrated that the time required to store and discharge heat is reduced by using foams, such as a copper foam bonded to a material that undergoes the phase change [ 9 ], a paraffin/copper foam and paraffin/nickel foam composite [ 10 ], and conductive foams and finned pipes [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

Thermal Energy Storage and Heat Transfer of Nano-Enhanced Phase Change Material (NePCM) in a Shell and Tube Thermal Energy Storage (TES) Unit with a Partial Layer of Eccentric Copper Foam

et al. 2021

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Thermal energy storage units conventionally have the drawback of slow charging response. Thus, heat transfer enhancement techniques are required to reduce charging time. Using nanoadditives is a promising approach to enhance the heat transfer and energy storage response time of materials that store heat by undergoing a reversible phase change, so-called phase change materials. In the present study, a combination of such materials enhanced with the addition of nanometer-scale graphene oxide particles (called nano-enhanced phase change materials) and a layer of a copper foam is proposed to improve the thermal performance of a shell-and-tube latent heat thermal energy storage (LHTES) unit filled with capric acid. Both graphene oxide and copper nanoparticles were tested as the nanometer-scale additives. A geometrically nonuniform layer of copper foam was placed over the hot tube inside the unit. The metal foam layer can improve heat transfer with an increase of the composite thermal conductivity. However, it suppressed the natural convection flows and could reduce heat transfer in the molten regions. Thus, a metal foam layer with a nonuniform shape can maximize thermal conductivity in conduction-dominant regions and minimize its adverse impacts on natural convection flows. The heat transfer was modeled using partial differential equations for conservations of momentum and heat. The finite element method was used to solve the partial differential equations. A backward differential formula was used to control the accuracy and convergence of the solution automatically. Mesh adaptation was applied to increase the mesh resolution at the interface between phases and improve the quality and stability of the solution. The impact of the eccentricity and porosity of the metal foam layer and the volume fraction of nanoparticles on the energy storage and the thermal performance of the LHTES unit was addressed. The layer of the metal foam notably improves the response time of the LHTES unit, and a 10% eccentricity of the porous layer toward the bottom improved the response time of the LHTES unit by 50%. The presence of nanoadditives could reduce the response time (melting time) of the LHTES unit by 12%, and copper nanoparticles were slightly better than graphene oxide particles in terms of heat transfer enhancement. The design parameters of the eccentricity, porosity, and volume fraction of nanoparticles had minimal impact on the thermal energy storage capacity of the LHTES unit, while their impact on the melting time (response time) was significant. Thus, a combination of the enhancement method could practically reduce the thermal charging time of an LHTES unit without a significant increase in its size.

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Thermal performance evaluation of non-uniform fin array in a finned double-pipe latent heat storage system

Cited by 135 publications

References 57 publications

Investigation of Heat Transfer Enhancement in a Triple Tube Latent Heat Storage System Using Circular Fins with Inline and Staggered Arrangements

Investigation of Heat Transfer Enhancement in a Triple Tube Latent Heat Storage System Using Circular Fins with Inline and Staggered Arrangements

Optimum Placement of Heating Tubes in a Multi-Tube Latent Heat Thermal Energy Storage

Thermal Energy Storage and Heat Transfer of Nano-Enhanced Phase Change Material (NePCM) in a Shell and Tube Thermal Energy Storage (TES) Unit with a Partial Layer of Eccentric Copper Foam

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