Conference Papers
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Item Effect of geometry on heating and cooling characteristics for thermal energy storage-A Computational Study(Toronto Metropolitan University, 2019) Chavan, S.; Gumtapure, V.; Arumuga Perumal, D.A.In the present work an attempt is made to understand the effect of geometry on heating and cooling characteristics for thermal energy storage applications. Three different geometrical models (square, pentagon and hexagon) are selected and thermal storage material used is composite of paraffin wax (98%) and Al2O3 nanoparticles (2%) [1-2]. The heating and cooling processes are analyzed by applying constant heat flux and the boundary conditions imposed are: Heating cycle (i) Constant heat flux is applied to left wall (for square) and upper left wall (for pentagon and hexagon). Cooling cycle (ii) Constant heat rejection through right wall (for square) and lower right wall (pentagon and hexagon). (iii) Remaining all other walls are Insulated for both the cases. The geometrical 2-D model is created by using ICEMCFD16.0 pre-processing software of ANSYS 16.0 version, in order to interpret the superior results good quality mesh is generated all over the computational domain. At the boundaries, the mesh size is reduced and made a uniform to response imposition of inputs and resolve the boundary layer conflicts. In order to reduce the computational time, relatively larger mesh is maintained at the center part of the domain. To investigate the problem Fluent 16.0 is used and concerned parameters are defined, boundary conditions are imposed and temperature dependent user-defined functions (UDF) are interpreted. The numerical investigation aims to understand the effect of geometry on heating and cooling characteristics using composite phase change material. The streamline patterns, liquid fractions and temperature distribution profiles are analyzed and among the models square and hexagonal model shown quicker melting (completed melting within 4000 sec). The liquid fraction variation is also similar and uniform, the temperature variation during complete melting process is least in square model followed by pentagonal model. However, liquid fraction variation is least in pentagonal model. Temperature variation during heating is maximum in case of hexagonal model (14%) increase in temperature. Liquid fraction variation is uniform and smooth in hexagonal model and consumed 50% less time than pentagonal model. The cooling cycle analysis also explored some interesting results, cooling rate is very quick in square model but for optimal thermal storage unit heat rejection process should not be too steep. Pentagonal model shown insignificant characteristics during both heating and cooling processes. The hexagonal model exhibited uniform and gradual variation in liquid fraction as well as temperature variation during the process. For ideal thermal storage device quicker heating is expected and heat rejection should be gradual and relatively slower (specially for long term storage applications). Among all the cases if only heating is required then square model will be the best selection but to achieve optimal heating and cooling hexagonal model will be the best option. © 2019, Toronto Metropolitan University. All rights reserved.Item Numerical Investigation of Polyethylene-Based Composite Phase Change Material in Cylindrical Shell and Coil Thermal Energy Storage(Springer Science and Business Media Deutschland GmbH, 2023) Sheikh, M.I.A.R.; Ahammed, M.E.; Gumtapure, V.In the context of energy conversion systems, understanding the performance of thermal energy storage is crucial. Latent thermal energy storage (LTES) system is a prominent application of energy conversion system due to its high volumetric energy holding capacity. However, its performance is limited due to unfavorable thermophysical properties of phase change material (PCM). Linear low-density polyethylene (LLDP) is a justified potential PCM due to the huge waste recycled material piled up every year based on massive use of plastic products. Present numerical work explores performance enhancement of a shell and coil-based LTES system. The thermophysical properties of LLDP are improved by adding functionalized graphene in the proportion of 1%, 3% and 5% in the composition termed as CPCM1, CPCM2 and CPCM3, respectively. The results confirm that adding graphene decreases the charging time of LTES, maximum up to 40%, and the average temperature of PCM increases along with the concentration of graphene. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.