This paper reports the two-dimensional (2D) transient numerical simulation of a phase change material (PCM) based finned heat sink to investigate the heat transfer performance for passive cooling of electronic devices. The finned heat sinks of 2 mm and 3 mm fin thickness are employed with a constant fin volume fraction of 9%, acting as thermal conductivity enhancer (TCE). The n-eicosane is employed as a PCM inside the heat sink to store the heat generated from the electronic device applied at the heat sink base. Transient numerical simulations are performed using finite-volume-method and conjugate heat transfer and melting/solidification phenomenon are investigated by applying various power levels. The numerical results show that the employed PCM with low temperature keeps the heat sink base temperature in lower limits and uniform melting is observed inside the finned heat sink.With the increase of heating power level, the PCM melting time is decreased for fin thickness heat sinks. By increasing the power level from 4 to 6W, for the case of 3 mm fin thickness, the melting time increases by 6.63%, 3.59% and 1.90% by 3 mm fin thickness heat sink, compared to the 2 mm fin thickness heat sink. The developed equations of liquid fraction and modified Nusselt number are obtained as function of modified Fourier number, Stefan number, and Rayleigh number which provide guidelines for generalizing the performance of PCM based finned heat sinks.

Summary This article presents two‐dimensional (2D) transient numerical simulation and mathematical modeling of a heat sink based on nano‐enhanced phase change materials (NePCMs) to study their performance for the cooling of an electronic component. n‐eicosane is used as a PCM and Al2O3, ZnO, CuO and Cu are used as nanoparticles in NePCMs. An electronic component is mounted in the center of the bottom wall and which an aluminum fin simulating the role of a substrate (motherboard) occupies. The NePCM completely fills the inner part of the heat sink. The NePCM store the heat generated by the protuberant electronic component. The transient regime is numerically performed adopting the finite volume method and the enthalpy‐porosity technique. It has been found that the mean heat transfer and the fluid flow structure are closely dependent on the nanoparticles type in NePCM. The addition of single NePCM, with volume fractions of 2% and 4%, decreases the electronic component operating temperature and the latent heat phase duration during which the electronic component operates safely. The hybrid NePCM shows a different behavior by decreasing the electronic component operating temperature and increasing the latent phase duration. Compared to pure PCM, by inserting a volume fraction of 4%‐Cu, the electronic component working temperature decreases by 4.69% and the latent heat phase duration decreases by 3.33%. Compared to pure PCM, hybrid nanoparticle insertion of 1%‐Al2O3 and 3%‐Cu showed a 5.77% decrease in the electronic component operating temperature and a 31.11% increase in the latent heat phase duration. By inserting hybrid nanoparticles instead of single nanoparticles, the effective thermal effusivity of NePCM is improved by 10.85%.

Phase change materials (PCMs) are used as latent heat thermal energy storage materials. The fields of application for PCMs are broad and diverse. Among these areas are thermal control of electronic components and thermal building regulations. These areas are used as heat and cold storage materials. The low thermal conductivity of PCMs is one of the significant and severe technological problems of PCMs. This paper presents a review of the latest works using PCMs in the thermal management of electronic components, buildings, and heat exchangers. Besides, it provides concise pieces of information on the classification of PCMs, their advantages, disadvantages, and thermal storage systems.

The present paper reports numerical results of the melting driven natural convection in an inclined rectangular enclosure filled with nano-enhanced phase change material (NePCM). The enclosure is heated from the bottom side by a flush-mounted heat source (microprocessor) that generates heat at a constant and uniform volumetric rate and mounted on a substrate (motherboard). All the walls are considered adiabatic. The purpose of the investigation is analyzing the effect of nanoparticles insertion by quantifying their contribution to the overall heat transfer. Combined effects of the PCM type, the inclination angle and the nanoparticles fraction on the structure of the fluid flow and heat transfer are investigated. A 2D mathematical model based on the conservation equations of mass, momentum, and energy was developed. The governing equations were integrated and discretized using the finite volume method. The SIMPLE algorithm was adopted for velocity–pressure coupling. The obtained results show that the nanoparticles insertion has an important quantitative effect on the overall heat transfer. The insertion of metallic nanoparticles with different concentrations affects the thermal behavior of the heat sink. They contribute to an efficient cooling of the heat source. The effect of nanoparticles insertion is also shown at the temperature distribution along the substrate.

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The current two-dimensional (2D) numerical study presents the melting phenomenon and heat transfer performance of the nanocomposite phase change material (NCPCM) based heat sink. Metallic nanoparticles (copper: Cu) of different volume fractions of 0.00, 0.01, 0.03, and 0.05 were dispersed in RT-28HC, used as a PCM. Transient simulations with conjugate heat transfer and melting/solidification schemes were formulated using finitevolume-method (FVM). The thermal performance and melting process of the NCPCM filled heat sink were evaluated through melting time, heat storage capacity, heat storage density, rate of heat transfer and rate of heat transfer density. The results showed that with the addition of Cu nanoparticles, the rate of heat transfer was increased and melting time was reduced. The reduction in melting time was obtained of −1.36%, −1.81%, and −2.56% at 0.01, 0.03, and 0.05, respectively, compared with 0.00 NCPCM based heat sink. The higher heat storage capacity enhancement of 1.87% and lower reduction of −7.23% in heat storage density was obtained with 0.01 volume fraction. The enhancement in rate of heat transfer was obtained of 2.86%, 2.19% and 1.63%; and reduction in rate of heat transfer density was obtained of −6.33%, −21.05% and −31.82% with 0.01, 0.03, and 0.05 volume fraction of Cu nanoparticles, respectively. The results suggest that Cu nanoparticles of 0.01

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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.