PCM Melting in Triplex Tube with Internal-External Fins, Paper Numerical Validation, CFD Simulation by ANSYS FluentDescriptionThis project simulates the melting process of a phase change material (PCM) within a triplex tube fitted with internal and external fins, using ANSYS Fluent. The simulation is based on the reference article "Enhance heat transfer for PCM melting in a triplex tube with internal-external fins," with results compared and validated against the paper's published data.The simulation is performed in two dimensions, modeling only a hollow circular cross-section of the pipe. The geometry features 4 rows of outer fins connected to the pipe's inner diameter wall and 4 rows of inner fins connected to its outer diameter wall, with both walls and their respective fins made of copper. The PCM used inside the tube is RT-82, defined with an initial density of 770 kg/m³ under the Boussinesq model, a specific heat capacity of 2000 J/kg·K, thermal conductivity of 0.2 W/m·K, and viscosity of 0.03499 kg/m·s.The 2D geometry was designed in Design Modeler and meshed in ANSYS Meshing using a structured grid totaling 17,856 elements.MethodologySince the objective is to track the evolving solid and liquid phase regions as melting and freezing progress over time, the Solidification and Melting model was applied. This model was configured with a solidus temperature of 70°C (the maximum temperature at which the material remains fully solid) and a liquidus temperature of 82°C (the minimum temperature at which it becomes fully liquid), along with a latent heat of fusion of 176,000 J/kg for the pure PCM.Both the tube's inner wall with its outer fins, and the outer wall with its inner fins, were held at a constant temperature of 90°C, while the PCM inside the tube started at an initial temperature of 27°C. Given the goal of tracking the PCM's melting behavior over time, the simulation was run as unsteady (transient).ConclusionResults were compared directly against the reference paper using Figures 7 and 13, which track the PCM's average temperature over time and the liquid mass fraction resulting from melting over time, respectively. This comparison specifically corresponds to the paper's case where the PCM is influenced simultaneously by both the internal and external fins — with the present CFD results showing close agreement with the article's reported values across this comparison.Additional 2D contours of pressure, temperature, and liquid mass fraction were extracted at multiple points throughout the transient simulation, capturing how the melting front and internal temperature distribution evolve over time as the PCM transitions from solid to liquid under the combined influence of the internal and external fin arrangement.

Thermal Storage by PCM in a Triplex Tube Heat Exchanger, Paper Numerical Validation by ANSYS FluentDescriptionThis project simulates heat transfer within a triplex tube heat exchanger containing a phase change material (PCM), based on the reference article "Internal and external fin heat transfer enhancement technique for latent heat thermal energy storage in triplex tube heat exchangers," with results compared and validated against the paper's published data. A triplex tube heat exchanger consists of two coaxial tubes dividing the cross-section into three distinct regions.The inner and outer tubes were modeled as aluminum, with the PCM flowing through the annular space between them. Two configurations were modeled: an unfinned case (matching Case A in the article) and a finned case incorporating four internal fins (matching Case B). The PCM used, RT82, was defined per the article's Table 4: density of 770 kg/m³, specific heat capacity of 2000 J/kg·K, thermal conductivity of 0.2 W/m·K, viscosity of 0.03499 kg/m·s, a solidus temperature of 350.15 K, a liquidus temperature of 358.15 K, and a latent heat of fusion of 176,000 J/kg. The Solidification and Melting model captured the PCM's phase-change behavior throughout the simulation.The inner wall of the inner tube and the outer wall of the outer tube were treated as thermally insulated, while the outer wall of the inner tube and the inner wall of the outer tube — both in direct contact with the PCM — were held at a constant 363.15 K.Geometry & MeshThe 2D geometry was designed in Design Modeler as a cross-section of the three-tube heat exchanger, modeled in two configurations. Both share the same coaxial circular geometry: the inner tube has inner and outer radii of 25.4 mm and 26.6 mm, while the outer tube has inner and outer radii of 75 mm and 76 mm. The first configuration includes no fins, while the second adds two fins on the inner tube's outer wall facing two corresponding fins on the outer tube's inner wall.The domain was meshed in ANSYS Meshing using a structured grid, totaling 23,908 elements for the unfinned case and 24,492 elements for the finned case.MethodologySeveral assumptions were applied: a pressure-based solver was used, the simulation was run as unsteady to capture the time-dependent solidification and melting process, and gravitational effects were included at -9.81 m/s² along the Y-axis.Key simulation settings included:Viscous model: Laminar, with the energy equation enabled and the Solidification & Melting model activatedBoundary conditions: The PCM-contacting walls (outer wall of inner tube, inner wall of outer tube) set as stationary walls with coupled thermal condition at 363.15 K; the insulated walls (outer wall of outer tube, inner wall of inner tube) set as stationary with zero heat fluxSolution methods: SIMPLE pressure-velocity coupling, PRESTO! for pressure discretization, and second-order upwind schemes for both momentum and energyInitialization: Standard method, with 0 Pa gauge pressure, zero velocity components, and an initial temperature of 300 KConclusionValidation was performed against Figure 14 of the reference article, which tracks the melting fraction over time across several fin configurations — with this simulation specifically reproducing Cases A and B from the paper's Figure 2. The results confirm that nearly all of the PCM converts to liquid phase after a sufficient elapsed time, consistent with the reference data.Additional 2D contours of temperature and liquid mass fraction were obtained for both the finned and unfinned models, showing that liquid volume fraction increases correspondingly as PCM temperature rises — with the finned configuration expected to accelerate this melting process relative to the unfinned case, consistent with the enhanced heat transfer pathway the internal fins provide.

Shell and Tube Heat Exchanger, PCM Thermal Storage System, Paper Numerical Validation, CFD Simulation by ANSYS FluentDescriptionThis project simulates the solidification and melting of a phase change material (PCM) within a shell and tube heat exchanger, based on the reference article "Experimental and computational evolution of a shell and tube heat exchanger as a PCM thermal storage system," with results compared and validated against both the experimental and numerical results reported in the paper.Phase change materials are organic compounds capable of absorbing and storing large amounts of latent thermal energy. This energy storage occurs during the phase transition itself: as the material melts from solid to liquid, it absorbs heat from its surroundings (producing a cooling effect), while as it solidifies from liquid back to solid, it releases that stored heat back into the environment (producing a heating effect).The PCM used in this simulation is RT50-type paraffin, defined with a density of 820 kg/m³, specific heat capacity of 2000 J/kg·K, and thermal conductivity of 0.2 W/m·K. Its viscosity was defined as temperature-dependent, implemented through a UDF using an exponential function of temperature.The heat exchanger itself is constructed from copper, with water flowing through the inner tube at a mass flow rate of 0.008318 kg/s and a temperature of 343.15 K, while the surrounding shell section is filled with the PCM.Geometry & MeshThe 3D geometry was designed in Design Modeler, representing a shell and tube heat exchanger with an inner tube wall thickness of 0.0025 m. The pipe spans 1 m in length, with inner and outer radii of 0.011 m and 0.0425 m, respectively. Given the pipe's symmetrical structure, only half the geometry was modeled to reduce computational cost.The domain was meshed in ANSYS Meshing using a structured grid totaling 169,171 elements.MethodologyThe Solidification and Melting model was used to capture the PCM's phase-change behavior, defined with a solidus temperature of 317.2 K, a liquidus temperature of 327.3 K, and a latent heat of fusion of 170,320 J/kg.ConclusionA graph tracking the temperature evolution of the PCM-filled shell section over the course of a complete melting cycle was extracted and compared directly against Figure 8 of the reference article, which includes both experimental measurements and numerical CFD results. This comparison confirmed that the current simulation achieves acceptable accuracy relative to both the numerical and experimental results reported in the paper.Additional 2D and 3D contours of pressure, temperature, and liquid mass fraction were also obtained, providing a detailed view of how the PCM transitions from solid to liquid throughout the shell as it absorbs heat from the circulating hot water in the inner tube.

PCM Components in Hot Water Tank Thermal Analysis (Load & Discharge), CFD Simulation TrainingDescriptionA Phase Change Material (PCM) is a substance capable of releasing or absorbing substantial energy during a phase transition, making it useful for heating or cooling applications. This transition typically occurs between the solid and liquid states, though it can also occur between non-classical states of matter — such as a crystal shifting between different crystalline structures representing higher or lower energy states.By melting and solidifying at a defined Phase Change Temperature (PCT), a PCM can store and release far more energy than conventional sensible heat storage, since heat is absorbed or released specifically as the material's phase or internal structure changes — a mechanism that gives PCMs their designation as Latent Heat Storage (LHS) materials.This project simulates a system of 16 PCM capsules positioned within a water tank. Hot water enters the domain at 0.5 m/s and 335 K, driving the PCM capsules through a complete melting cycle; once fully liquid, cold water is introduced to cool the system, initiating the reverse solidification process as the PCMs release their stored thermal energy.Geometry & MeshThe 3D domain was designed in Design Modeler, featuring an inlet, an outlet, and dedicated wall boundaries representing the PCM capsules. The domain was meshed in ANSYS Meshing using an unstructured grid totaling 339,466 elements.MethodologySeveral assumptions were applied to the simulation: a pressure-based solver was used, gravitational effects were excluded, and the simulation was run as unsteady.Key simulation settings included:Viscous model: SST k-omega, with the energy equation enabledBoundary conditions: Velocity inlet at 0.5 m/s, with hot water entering at 333 K and cold water at 272 K; pressure outlet at 0 Pa gauge pressure; stationary tank walls with no thermal condition applied; stationary PCM capsule walls with a coupled thermal conditionConclusionThe average temperature trends for both the surrounding environment and the PCM capsules reveal a clear two-stage thermal cycle. As hot water enters the domain, the environment's temperature rises, correspondingly driving up the PCMs' average temperature and initiating melting at around 343 seconds; by 1500 seconds, all PCM capsules have fully melted.Once cold water is introduced, the domain's average temperature begins to decline, though the PCMs release their stored latent heat more gradually — causing their own average temperature to decrease at a notably slower rate than the surrounding water. Solidification begins roughly 500 seconds after the cold water enters, with the PCM capsules fully solidified by 4500 seconds — confirming the system's ability to store and later release thermal energy across a complete charge-discharge cycle.

Thermal Management by PCM in a Room Wall, CFD Simulation ANSYS Fluent TutorialDescriptionA Phase Change Material (PCM) releases or absorbs substantial energy as it melts and solidifies at a specific temperature, making it well-suited for temperature control applications — absorbing significant heat during melting and releasing that stored heat back during solidification. PCMs find use across a range of applications requiring stable temperatures and energy storage, including heating pads, cooling systems for telephone switching boxes, and thermally responsive fabrics used in bedding and clothing.This project models a square-shaped room whose wall consists of three material layers: brick, Trimethylolethane/water (the PCM layer), and concrete, arranged from outer to inner surface. The brick's outer surface is exposed to a heat flux of 100 W/m², with all three wall materials sharing low thermal conductivity — a combination intended to help the room resist rapid thermal fluctuations.The 3D geometry represents a 3 m square domain plus the three wall layers, each 10 cm thick, built in Design Modeler. The domain was meshed in ANSYS Meshing using a structured grid totaling 193,500 elements.MethodologyThe Solidification and Melting model was used to simulate the PCM's thermal loading behavior. A pressure-based solver was employed given the fluid's incompressibility, and since the process depends inherently on time, the simulation was run as transient, with gravitational effects excluded.ConclusionResults include 2D contours and vector fields of pressure, temperature, turbulence kinetic energy, and velocity. The results show that reaching a PCM volume fraction of 1 — meaning the Trimethylolethane/water layer melts completely — takes approximately 6 days, illustrating how long this material takes to fully store the energy it absorbs from incoming radiation.The room's interior temperature rises only very gradually throughout this process, a direct result of the low thermal conductivity shared by all three wall components (brick, PCM, and concrete). This behavior confirms the PCM's effectiveness at storing thermal energy for later use, supporting reduced energy and power consumption by smoothing out and delaying the transfer of heat into the living space.

Passive Ventilation by PCM, ANSYS Fluent CFD Simulation TutorialDescriptionPhase change materials (PCMs) can store thermal energy and release it back to the environment as needed, enabling both cooling, heating, and thermal storage through their transition between solid and liquid states. When ambient temperature rises, the material transitions from solid to liquid, storing the latent energy of melting in the process; when temperature later drops, the material transitions back to solid, releasing that stored latent energy of solidification. Since this heat transfer occurs without any mechanical device, PCM-based systems fall within the broader category of passive ventilation.This passive ventilation system operates on the buoyancy effect, where temperature-driven density differences drive natural convection. This project models such a system in two stages: first, examining natural convection heat transfer in a simple room with one wall subjected to a constant heat flux (representing warm ambient air and incoming solar radiation), and second, applying a PCM panel to that same heated wall to evaluate its effect on the resulting heat transfer into the room.The geometry for both stages was designed in Design Modeler, with the first stage modeling a simple room and the second adding the PCM panel. Both models were meshed in ANSYS Meshing using a structured grid, totaling 228,448 elements for the first stage and 241,560 for the second.MethodologyThis problem was solved as unsteady, time-dependent CFD using a pressure-based solver. Since the PCM's operating mechanism relies on continuous phase change between solid and liquid, the Solidification and Melting model was applied, requiring three defining parameters: the solidus temperature (the maximum temperature at which the material remains fully solid), the liquidus temperature (the minimum temperature at which it becomes fully liquid), and the pure solvent's latent heat of melting.Since natural convection — driven by the buoyancy effect — also plays a central role in this problem, air density was not treated as constant. Instead, the incompressible ideal gas model was used, applying the ideal gas relationship between density, pressure, and temperature; since density in this model depends on operating pressure rather than local relative pressure, assuming constant pressure effectively makes density a function of temperature alone — precisely what's needed to capture the buoyancy-driven flow.ConclusionResults include a plot of the room's average temperature over time, comparing the with-PCM and without-PCM cases, along with 2D and 3D temperature contours and velocity vectors for both scenarios.In the first simulation (without PCM), room temperature rises steadily over time as the wall's heat flux drives heat transfer into the space. In the second simulation (with the PCM panel), temperature rises with a noticeably shallower slope — even though the same heat flux is applied, the PCM layer positioned between the heat source and the room interior absorbs much of that incoming heat as latent heat during its phase change, allowing significantly less heat to actually penetrate into the room. This confirms the PCM panel's effectiveness at moderating and delaying heat transfer in a passive ventilation context, directly reducing the room's temperature rise without any active mechanical cooling system.

PCM Based Encapsulation in Energy Efficient BuildingsDescriptionThis study investigates the effect of PCM-based encapsulation on building thermal performance, comparing heat loads before and after PCM integration within the walls. Since PCMs store and release thermal energy during their phase transitions, embedding PCM capsules into building walls offers a way to regulate indoor temperature and reduce both cooling and heating demand. This project evaluates that energy storage capacity and its resulting impact on peak thermal load reduction.The simulation models a standard room with defined dimensions, material properties, and internal heat sources. The thermal load is first calculated without any PCM present, under varying external temperature conditions, establishing a baseline. PCM capsules are then embedded within the walls, and their phase transition behavior is analyzed in detail, tracking key parameters such as energy storage capacity and liquid fraction — the latter indicating the PCM's current phase state — over time.MethodologyThis project uses transient heat transfer simulations structured around several key stages. The baseline thermal load is first established using conduction, convection, and radiation heat transfer models without any PCM present. PCM capsules are then introduced into the walls, with their thermophysical properties — including melting point and latent heat — explicitly defined.The PCM's energy storage behavior is assessed across both its charging (melting) and discharging (solidification) cycles, capturing how effectively it absorbs and later releases heat. Throughout this process, the liquid fraction — the proportion of PCM currently in its liquid phase — is tracked continuously to determine how effectively the material stabilizes indoor temperature as it cycles between phases.ConclusionComparing thermal load before and after PCM integration reveals a clear reduction in peak cooling and heating demand, with the quantified energy storage capacity confirming the PCM's role in shifting thermal load away from peak periods. The liquid fraction analysis further reveals how efficiently the PCM transitions between phases, directly shaping its heat-regulating performance.Most notably, incorporating PCM capsules into the room's walls reduced the average room temperature by 7.7°C compared to the scenario without PCM — a substantial improvement in thermal regulation. This reduction stems directly from the PCM's ability to absorb and store heat during its phase transitions, smoothing out temperature fluctuations and improving overall thermal comfort within the space. These findings support the broader use of PCM-based building materials as an effective strategy for improving energy efficiency and creating more thermally stable indoor environments.

PCM Solar Collector CFD Simulation by ANSYS Fluent TutorialDescriptionThis project simulates heat transfer within a PCM-based solar collector using ANSYS Fluent. The system centers on a U-shaped tube carrying water flow, surrounded by a cylindrical space filled with phase change material (PCM). This PCM region is itself enclosed by three concentric layers: an aluminum layer that absorbs incoming solar radiation, an air gap layer, and an outer glass layer.The collector operates through a straightforward thermal pathway: sunlight passes through the glass layer, heating the enclosed air gap; this heat then transfers to the aluminum absorber layer, which in turn transfers heat inward to the PCM. During the day, as the absorber captures solar heat, the PCM absorbs part of this energy to drive its melting process. At night, as ambient conditions cool, the PCM releases its stored latent heat by solidifying, transferring that heat into the water flowing through the U-shaped tube — effectively storing daytime solar heat for use during colder nighttime hours.Geometry & MeshThe 2D geometry was designed in Design Modeler, consisting of two parallel pipes forming the U-shaped tube, surrounded by the cylindrical PCM layer. Around this, an incomplete cylindrical aluminum absorber layer was placed, followed by an incomplete cylindrical air gap layer, and finally an incomplete cylindrical glass layer as the outermost boundary.The domain was meshed in ANSYS Meshing using a structured grid totaling 969,866 elements.MethodologyThe Solidification and Melting model was used to represent the PCM's phase-change behavior, with the material defined by a density of 910 kg/m³, specific heat capacity of 2100 J/kg·K, thermal conductivity of 0.5 W/m·K, and viscosity of 0.0273 kg/m·s. Its solidus temperature was set to 302 K, liquidus temperature to 310 K, and latent heat of fusion to 178,000 J/kg.Radiative heat transfer and incoming solar radiation were captured using the Discrete Ordinates (DO) radiation model, which solves the radiative transfer equations across a discrete set of finite solid angles — well suited to this system's transparent glass layer, reflective surfaces, and wavelength-dependent transmission behavior. Solar ray tracing was activated to apply the solar load directly, requiring inputs such as the site's longitude and latitude, the date and time of the simulated radiation, solar direction, and both direct and diffuse radiation intensities. The laminar model and energy equation were enabled to solve the fluid flow and capture temperature variation throughout the domain.ConclusionResults include 2D and 3D contours of pressure, velocity, temperature, and the liquid mass fraction produced within the PCM. The results confirm that the PCM within the central cylindrical region undergoes a clear phase change, generating liquid within that zone as it absorbs solar heat. Comparing the U-shaped tube's inlet and outlet temperatures further confirms that heat is successfully transferred into the water flow — validating the collector's core function of capturing, storing, and later releasing solar thermal energy through the PCM's melting-solidification cycle.

PCM-Enhanced PV Panel, ANSYS Fluent CFD SimulationDescriptionThermal management of photovoltaic (PV) systems presents a significant challenge in solar energy technology, since PV modules can experience temperature increases of up to 35°C above ambient conditions during peak sunlight exposure — a rise that substantially impacts performance, with power output declining by approximately -0.65% for every 1°C increase in temperature.This project compares two configurations: a conventional PV panel without any cooling enhancement, and an enhanced system incorporating PCM-based passive cooling. The PV system was modeled as a multi-layer structure comprising a glass cover layer, an Ethylene-Vinyl-Acetate (EVA) layer, silicon solar cells, a second EVA layer, and a Tedlar back sheet, with the PCM-enhanced configuration additionally incorporating a layer of RT42 paraffin PCM.The full 3D geometry, including both the conventional and PCM-enhanced configurations, was built in SpaceClaim, capturing all PV panel layers along with the PCM containment structure. The domain was meshed in ANSYS Meshing using a structured grid of approximately 1,000,000 elements, sized to adequately resolve thermal gradients while maintaining computational efficiency.MethodologyThe Solidification and Melting model was activated to capture the PCM's phase-change dynamics, while the Discrete Ordinates (DO) radiation model captured radiative heat transfer throughout the system. Solar ray tracing was enabled for precise solar load calculations, using location-specific parameters set to longitude -84.63°, latitude 13.65°, and UTC-5 time zone — eliminating the need for simplified radiation source terms and enabling more realistic solar irradiation modeling. Momentum equations were deliberately disabled, focusing computational resources specifically on the system's thermal behavior.The simulation ran over a period of 19,500 seconds (approximately 5.4 hours) to evaluate thermal performance across both configurations.ConclusionThe PCM-enhanced system achieved an average PV temperature of 313.25 K (40.1°C), compared to 315.06 K (41.91°C) for the conventional system — a difference of 1.81 K. The PCM-enhanced configuration also showed a notably more uniform temperature distribution across the panel, with temperature contours revealing effective heat absorption by the PCM layer and lower peak temperatures thanks to its thermal buffering effect; by contrast, the conventional system exhibited higher thermal gradients and less uniform distribution overall.Liquid fraction contours reveal the PCM's phase transition progressing gradually from top to bottom, with liquid fraction values ranging from 0.122 to 0.267 — confirming a progressive, effective thermal energy storage process rather than an abrupt phase change. The PCM case also showed a broader overall temperature range (312–317 K) compared to the conventional case (312–315 K), reflecting the PCM's role in redistributing and moderating heat across the panel.This 1.81 K temperature reduction translates to an estimated 1.18% improvement in electrical efficiency, based on the standard -0.65%/°C temperature coefficient for PV performance. Beyond the direct efficiency gain, the more stable operating temperature also suggests reduced thermal stress on PV components and improved long-term reliability — confirming that PCM-based passive cooling offers a measurable, meaningful improvement in PV thermal management under realistic solar loading conditions.

Battery Cooling (Thermal Management) by PCM, ANSYS Fluent TrainingDescriptionThis project simulates the cooling of a lithium battery through phase change material (PCM) application, using ANSYS Fluent. The simulation proceeds in two stages: first modeling a single lithium battery on its own, then adding two PCM layers on either side of the battery body — allowing a direct comparison of the PCM's effectiveness in the battery cooling process.The 3D geometry was designed in SolidWorks and imported into Design Modeler, built across two configurations. The initial battery model measures 11.3 mm thick, 335 mm long, and 167 mm wide; the second configuration adds two 12 mm thick PCM layers to both sides of the battery. The domain was meshed in ANSYS Meshing using a structured grid, totaling 93,090 elements for the first case and 276,660 for the second. Given the nature of this problem, a transient solver was used throughout.MethodologyAs the battery operates, the electric current flowing through it generates heat, raising its internal temperature. This behavior was captured using a volumetric heat source defined within the battery region, calculated as R·I² — where R is the battery's internal resistance (10 mΩ in this simulation) and I is the current intensity (86 A) — yielding a heat generation rate of approximately 120,000 W/m³.The Solidification and Melting model was used to represent the PCM's phase-change behavior, defined with a solidus temperature of 307 K, a liquidus temperature of 309 K, and a latent heat of fusion of 240,000 J/kg. The laminar model and energy equation were enabled to solve the governing flow equations and capture the resulting temperature distribution.ConclusionResults include 2D and 3D temperature contours for both simulation stages, directly compared at the end of the simulation, along with a plot tracking the battery's average temperature over a full hour for both the with-PCM and without-PCM cases.The results confirm that applying a PCM coating to the battery body meaningfully cools the battery and slows its rate of temperature rise compared to the uncoated case. Additional 2D and 3D contours of the PCM's liquid volume fraction, obtained specifically for the second simulation stage, further illustrate how the PCM's progressive phase change directly governs its heat transfer interaction with the battery body — confirming the PCM layer's role as an effective passive thermal management solution for battery cooling applications.