Numerical Study on the Thermal Enhancement of Phase Change Material with the Addition of Nanoparticles and Changing the Orientation of the Enclosure (original) (raw)
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2017
Latent heat thermal energy storage (LHTES) system uses a phase change material (PCM) to store or release thermal energy, thus reducing the overall consumption of energy in a system. But, the problem with the PCM is their low thermal conductivity that increases the melting and solidification time, which is not suitable for specific application areas, such as, battery thermal management, electronic cooling etc. To increase the thermal conductivity of PCM, different studies examine different approaches including extension of the heat transfer area using fins and honeycombs, thin metal strips, porous metals, copper chips, metal foam matrices, metal screens and spheres, carbon fiber brushes and chips, graphite matrices, microencapsulated PCM, multiple PCMs, carbon-based nanostructures graphene flakes, carbon nano-tubes, metallic nanoparticles, silver nano-wires, and bio-based composite PCM. The current study incorporates nanoparticle in PCM (nano-PCM) to increase the thermal conductivity of the PCM. Experimental studies are performed using Copper Oxide (50nm) and Aluminum Oxide (50nm) nanoparticles supplied by Sigma Aldrich and Rubitherm (RT-18) as base PCM, supplied by Rubitherm GmbH. The vertical cylindrical LHTES is composed of two concentric pipes; with the inner one carrying a heat transfer fluid at a constant temperature and the annular space containing a nano-PCM. The initial temperature of the nano-PCM is 5 C while the temperature of the heat transfer fluid is 40 C. The experimental results show that using nano-PCM reduces the melting time when compared to base PCM, but enhanced melting is observed when Copper Oxide nanoparticle is used.
Thermal Science, 2014
The heat transfer enhancement in the latent heat thermal energy storage system through dispersion of nanoparticle is reported. The resulting nanoparticle-enhanced phase change materials exhibit enhanced thermal conductivity in comparison to the base material. Calculation is performed for nanoparticle volume fraction from 0 to 0.08. In this study rectangular and cylindrical containers are modeled numerically and the effect of containers dimensions and nano particle volume fraction are studied. It has been found that the rectangular container requires half of the melting time as for the cylindrical container of the same volume and the same heat transfer area and also, higher nano particle volume fraction result in a larger solid fraction. The increase of the heat release rate of the nanoparticle-enhanced phase change materials shows its great potential for diverse thermal energy storage application.
Energy Procedia, 2017
A two dimensional numerical model is developed for melting of a nano based phase change material (PCM) such as n-octadecane with CuO nanoparticle in a square cavity. The governing equations are discretized using Finite Volume Method (FVM). The flow equations are solved using SIMPLER algorithm. Tri-Diagonal Matrix Algorithm (TDMA) is used to solve the corresponding algebraic equations. Enthalpy porosity technique is used to capture the position of the moving melt front. The melting of nano based phase change material with varying volume fractions of nanoparticles is studied to investigate the heat transfer enhancement during the melting process through dispersion of nanoparticles. The effect of some significant parameters, namely melting front progression, volume fraction of nanoparticle, heated left wall temperature, heat transfer rate and melting time are studied. The results obtained are represented graphically to study the nature and behavior of the parameters when are presented in terms of temperature, velocity profiles, moving interface position and solid fraction. Finally, it is concluded that addition of nanoparticles enhances the thermal conductivity as compared to conventional phase change material, resulting in a relatively higher heat transfer and a faster melting rate. In addition, with the rise in heat transfer rate of the nanofluid the melting time eventually decreased as the volume fraction of nanoparticles increased. Increase in difference between the melting temperature and the hot wall temperature fastened the melting process of the nano based PCM.
2019
Article history: Received 25 September 2018 Received in revised form 27 November 2018 Accepted 3 December 2018 Available online 11 May 2019 Phase change materials (PCM) has gain attention for years as a suitable medium in thermal energy storage system. Previous studies reported the use of PCM on PV panel increases the efficiency of heat storage system. One of the most common method to increase the thermal conductivity and improving the thermos physical properties of PCM is by adding nanoparticles making it as nano enhanced PCM. This review paper focuses on categories of PCM including organic, inorganic and eutectics. The enhancement of thermos physical properties such as latent heat and thermal conductivity of phase change materials is discussed. However, there are very few studies reported on specific heat capacity of nano-enhanced PCM (NEPCM). Thus the current study focuses on the enhancement of specific heat capacity for NEPCM. On the other hand, some PCM has disadvantages such a...
International Journal of Energy Research, 2020
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 Al 2 O 3 , 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%-Al 2 O 3 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%. K E Y W O R D S n-eicosane, nano-enhanced phase change materials, nanoparticles, passive cooling
IOP Conference Series: Materials Science and Engineering
The paper presents experimental investigations to evaluate thermal performance of heat pipe using Nano Enhanced Phase Change Material (NEPCM) as an energy storage material (ESM) for electronic cooling applications. Water, Tricosane and nano enhanced Tricosane are used as energy storage materials, operating at different heating powers (13W, 18W and 23W) and fan speeds (3.4V and 5V) in the PCM cooling module. Three different volume percentages (0.5%, 1% and 2%) of Nano particles (Al 2 O 3) are mixed with Tricosane which is the primary PCM. This experiment is conducted to study the temperature distributions of evaporator, condenser and PCM during the heating as well as cooling. The cooling module with heat pipe and nano enhanced Tricosane as energy storage material found to save higher fan power consumption compared to the cooling module that utilities only a heat pipe.
journal of energy storage
Ground source heat pump systems (GSHP) are one of the sustainable energy resources that provide heating and cooling to buildings. A stable ground temperature has a key role in the performance of the GSHP, in which the overuse (extract/release) of the underground energy can destabilize the ground temperature, leading to the system’s failure. A GSHP’s performance can be improved by stabilizing the ground temperature, which can be achieved by adding thermal energy storage (TES) to the system. This study aims to present a potential solution to improve the thermal performance of the GSHPs by coupling them to a latent heat TES system. PCMs are widely used for latent heat TES application; however, their poor thermophysical properties are a drawback, so adding nanoparticles has been considered as one of the solutions to address this drawback and improve PCM’s properties. This study investigated the thermal performance of a nano-enhanced phase change material (NE-PCM) as an underground TES by developing a finite element numerical model and validation of the experimental apparatus. To this end, PDA@hBN/MXene as a thermal enhancer has been used to develop the NE-PCM. Then, the NE-PCM was utilized in a storage tank with a diameter of 30 cm and a height of 60 cm. The experimental apparatus consists of 8 NE-PCM pipes and four borehole heat exchangers. The experimental temperature of the NE-PCM pipes was used to validate the numerical model for heating and cooling the system within 0.3 ◦C and 0.2 ◦C, respectively. Then, the numerical model was used to study the potential of the proposed TES in three scenarios, including no PCM, base PCM, and NE-PCM, with both parallel- and serial-connected heat exchangers. The total heat transfer with NE-PCM was increased by 38.4 % compared to no PCM case and 24.6 % compared to the base PCM. Lastly, the results of three different flow rates showed up to 11.5 % enhancement of the thermal storage efficiency by increasing the flow rates. The results show the potential of using the new NE-PCM in GSHP applications, adding the NE-PCM as the thermal storage medium can improve the performance of the hybrid TESGSHP system.
Thermal Energy Storage using Phase Change Materials and their Applications: A Review
This paper presents a review on thermal energy storage using Phase change material (PCM) and their applications. Latent heat thermal energy storage offers a huge opportunity to reduce fuel dependency and environmental impact produced by fossil fuel consumption. Solar energy is a renewable energy supply that can generate electricity, provide hot water, heat and cool a house and give lighting for buildings. In response to rising electrical energy costs, thermal storage technology has recently been developed. The selection of the substances to be used mostly depends upon the temperature level of the application. Phase change materials (PCMs) are one of the latent heat materials having low temperature range and high energy density of melting– solidification. Phase Change Materials (PCMs) are becoming more and more attractive for space heating and cooling in buildings, solar applications, off-peak energy storage, and heat exchanger improvements.
Thermal energy storage in general, and phase change materials (PCMs) in particular, have been a main topic in research for the last 20 years, but although the information is quantitatively enormous, it is also spread widely in the literature, and difficult to find. In this work, a review has been carried out of the history of thermal energy storage with solid-liquid phase change. Three aspects have been the focus of this review: materials, heat transfer and applications. The paper contains listed over 150 materials used in research as PCMs, and about 45 commercially available PCMs. The paper lists over 230 references.