Faculty Publications
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Item Characterization of linear low-density polyethylene with graphene as thermal energy storage material(Institute of Physics Publishing helen.craven@iop.org, 2019) Chavan, S.; Gumtapure, V.; Arumuga Perumal, D.A.In this work authors reported the preparation and characterization of composite phase change material (CPCM) using the direct-synthesis method by blending the Linear low-density polyethylene (LLDPE) with Carboxyl Functionalized Graphene (f-Gr). LLDPE is selected as base material and f-Gr is dispersed into three different concentrations 1.0, 3.0, and 5.0 wt% and referred as CPCM-1, CPCM-2 and CPCM-3 respectively. Experimental analysis is carried out through Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Differential scanning calorimeter (DSC). The preset study assesses the influences of nanoparticle concentration on thermophysical properties, thermal performance and thermal storage characteristics of CPCMs. Results show that addition of f-Gr improves the thermal conductivity and latent heat of fusion of LLDPE. However, f-Gr slightly reduces the melting temperature and decreased the crystallization temperature. Therefore, this study reveals that f-Gr, addition to LLDPE has substantial potential for improving the thermal energy storage performance. © 2019 IOP Publishing Ltd.Item Thermal property study of fatty acid mixture as bio-phase change material for solar thermal energy storage usage in domestic hot water application(Elsevier Ltd, 2019) B.V., R.M.; Gumtapure, V.For the correct design, simulation and specific application of the latent heat thermal energy storage (LHTES) system, detailed evaluation of phase change material (PCM) properties are essential. Present study aims to analyze the thermal and volume dependent behavior of available organic Bio-PCM OM55, using conventional thermal gravimetric analyzer (TGA), thermal constant analyzer (TCA), differential scanning calorimeter (DSC) and in-house T-history method (THM). Execution of the mentioned thermal analysis outcome with significant information of OM55. TGA shows that OM55 is thermally stable within the operating temperature 45–60 °C, because the maximum permissible degradation temperature 154.6 °C is much higher than operating temperature range. The OM55 has considerable thermal conductivity compared to the existing PCM, which is already used in domestic solar water heating (DSWH) applications. The evaluation of transition temperature, isothermal enthalpy, and specific heat by THM are well compared with the DSC analysis. Comparison of DSC and THM analysis showed that the behavior of OM55 is volume independent. The overall study concluded that OM55 is a potential Bio-PCM. However, for the optimum amount of energy storage and discharge in OM55, it is recommended to operate the LHTES unit over a temperature range between 46–59 °C for domestic hot water application. © 2019 Elsevier LtdItem Numerical and experimental analysis on thermal energy storage of polyethylene/functionalized graphene composite phase change materials(Elsevier Ltd, 2020) Chavan, S.; Gumtapure, V.; Arumuga Perumal, A.P.The main driving force behind the present work is environmental issues caused due to the usage of plastics, and energy issues. Current work attempts to address these problems by converting recycled plastics into thermal storage materials (TSM). Unfavorable thermophysical properties of plastic make it impractical but these inadequacies can be amended by blending with additives of superior thermophysical properties like, functionalized graphene. Numerical and experimental analysis are carried out to assess the thermal performance of TSMs (LLDPE, CPCM-1, CPCM-2 and CPCM-3) and check the compatibility of the materials. The phase change temperature of TSM is 123 to 125 °C and heat of fusion is 71.95 to 97 kJ/kg. Several thermal characteristics are analyzed to assess thermal performance and the amount of heat energy supplied, rate of heat transfer, and heat storage efficiency are deliberated. Results shown energy level enhancement of 43.17, 50.42, 54 and 50.61% for LLDPE, CPCM-1, CPCM-2 and CPCM-3 respectively. Among the TSM CPCM-2 shows relatively better storage capability (54% enhancement) due to incorporation of optimum concentration of enhancing material. The solidification process takes place through convection and radiation mode of heat transfer, at the completion of solidification process the TSM energy content reduces to 97.5, 96, 96 and 96% for LLDPE, CPCM-1,CPCM-2 and CPCM-3 respectively. This work concludes that, recycled plastics can be blended and it can be converted into efficient thermal storage material. © 2019 Elsevier LtdItem Thermo-physical analysis of natural shellac wax as novel bio-phase change material for thermal energy storage applications(Elsevier Ltd, 2020) B.V., B.V.; Gumtapure, V.The high energy density of latent heat storage makes it more competent than other types of thermal energy storage (TES) systems. Studying thermophysical and rheological properties of phase change material (PCM) is required for effective storage design, simulation, and applications. Bio-based PCM (BPCM) is a renewable and eco-friendly option for commercial paraffin-based PCMs. This study intends to characterize the shellac wax using the conventional and non-conventional approach as novel BPCM. Analysis of Fourier transforms infrared spectrophotometer (FTIR) indicates that shellac wax has aliphatic hydrocarbons, carboxylic acid, alcohol, and esters functional group. Thermogravimetric analysis (TGA) shows shellac wax has no mass change for operating temperature range (50–85 °C). Differential scanning calorimetry (DSC) analysis reported enthalpy of melting and crystallization as 148 kJ/kg and 161 kJ/kg, respectively. The crystallization enthalpy measured in the T-history method (THM) is 210.5 kJ/kg. However, DSC analysis of sample undergone 0,100,200 and 300 thermal cycle shows no significant change in thermal properties. Other properties like thermal conductivity, density, specific heat and viscosity are comparable to the present PCM used in storage applications. The overall study outcome that shellac wax is thermally stable and is potential BPCM for the TES application like solar desalination, district heating, waste heat recovery and solar cooking. © 2020 Elsevier LtdItem Computational investigation on the effect of geometrical parameters on thermal energy storage systems(Begell House Inc., 2021) Chavan, S.; Gumtapure, V.; Arumuga Perumal, D.The present work is an attempt to understand the effect of geometry on the heating and cooling characteristics of thermal energy storage systems. Three different geometrical models (square, pentagon, and hexagon) were considered and the thermal storage material used was a composite of paraffin wax (98%) and Al2O3 nanoparticles (2%). The heating and cooling processes were analyzed by applying a constant heat flux. Among the three models, the square model showed a faster melting rate but the cooling rate was too steep. The hexagonal model showed optimum results in both the heating and cooling processes with uniform and smooth variations in the liquid fraction and temperature. Hence, for optimal thermal storage applications the hexagonal model (or its geometries), which is close to the circular model, can be considered. © 2021 by Begell House, Inc.Item Performance assessment of composite phase change materials for thermal energy storage-characterization and simulation studies(Bentham Science Publishers, 2021) Chavan, S.; Gumtapure, V.; Arumuga Perumal, D.Background: The present study mainly focuses on the development of new Thermal Storage Materials (TSM) and compare the performance for thermal energy storage capacity. Linear Low-Density Polyethylene (LLDPE) based Composite Phase Change Materials (CPCMs) is prepared, and its properties are analyzed using characterization, analytical calculations, and numerical simulation meth-ods. The composites are prepared by blending the functionalized graphene nanoparticles (1, 3 & 5%) with three different concentrations into LLDPE. All three CPCMs show enhanced thermal performance compared to the base material, but it is noticed that higher concentrations of nanoparticles increase the dynamic viscosity and produce an adverse effect on thermal performance. Thermal characterization shows improved latent heat capacity with nanoparticle concentration, analytical and numerical results also compared, which shown a difference of 10 to 25%. Objective: The purpose of this study is the development and evaluation of the thermal storage capacity of different thermal storage materials and enlighten the techniques used for characterizing the storage materials. Methods: Composite material preparation is carried out by using twin-screw extruders, characterization of developed material is done through FTIR, SEM, and DSC analysis. For complete analysis character-ization, analytical calculations and numerical simulation methods are used. Results: Linear low-density polyethylene-based composite materials can be successfully developed using a twin-screw extruder. This extrusion provided proper dispersion of nanoparticles into the base material, and it is validated by SEM analysis. DSC analysis confirmed the enhancement in the thermo-physical properties of composite materials. Conclusion: The latent heat capacity increased around 20% during the heating cycle and reduced ap-proximately 23% during the cooling cycle for base material and 5% addition of nanoparticle, respec-tively. The comprehensive study accomplishes that the optimum concentration of nanoparticle provides better thermal performance for thermal energy storage applications. © 2021 Bentham Science Publishers.Item Experimental investigation of shellac wax as potential bio-phase change material for medium temperature solar thermal energy storage applications(Elsevier Ltd, 2022) B.V., B.V.; Thanaiah, K.; Gumtapure, V.Thermal performance of shellac wax as a novel bio-phase change material (BPCM) and Therminol®-55 as heat transfer fluid (HTF) in a vertical shell and tube latent heat thermal energy storage (LHTES) unit is analyzed experimentally. Operational parameters considered, namely HTF flow rate and inlet temperature in the range of 2–5 LPM and 100–120 °C, respectively. The comprehensive study of contours and plots reveals the impact of natural convection and the progress of the melting and solidification front in the charging and discharging process. As the HTF flow rate increases, the charging rate improves considerably, and a maximum reduction in melting time is obtained as 43.6% for 4 LPM. The maximum reduction in melting time and storage efficiency are 42.2% and 73.4%, respectively, at 120 °C and 4 LPM. However, the discharging process's increased flow rate has no significant effect on solidification and discharge efficiency, which attributes the dominant mode of heat transfer is conduction during the solidification. Shellac wax storage efficiency is comparable to existing paraffin wax, stearic acid and palmitic acid-based LHTES unit. In this regard, shellac wax can be a potential Bio-PCM for medium temperature range (60–80 °C) solar thermal applications such as domestic water heating and food drying. © 2021 International Solar Energy SocietyItem Thermal behavior of composite phase change material of polyethylene in a shell and coil-based thermal energy storage: Numerical analysis(Elsevier Ltd, 2023) Sheikh, M.I.A.R.; Ahammed, M.E.; Gumtapure, V.Energy management and environmental sustainability are important concerns across the world at present. In that context, using recycled waste material such as polyethylene as a phase change material (PCM) in a latent heat storage (LHS) system fulfils both motives. However, effective energy conversion requires proper design of thermal energy storage (TES) and improvement of thermophysical properties of the working material. In the present numerical analysis, a shell and coil-based TES is considered with linear low-density polyethylene (LLDP) as base material to be compounded with functionalized graphene in three different concentrations such as 1 %, 3 %, and 5 %, called composite phase change material i.e., CPCM1, CPCM2, and CPCM3 respectively. The diameter ratio between the coil and shell of TES, termed the geometrical ratio (Gr) is taken as 0.3, 0.5, and 0.7 in the analysis, whereas the coil's pitch length (pc) is varied from 10 mm to 30 mm. The orientation of TES is also varied from horizontal (0°) to vertical position (90°) with an interval of 30° inclination. Results reveal that the charging time for the complete liquefaction of storage material decreases a maximum of 65 % in the case of CPCM 3 with 5 % graphene. Increasing the heat supply from 125 W to 250 W sharply decreases the charging time, however, further increasing heat power affects moderately. The charging time gradually decreases to 56 % and 54 % in the case of LLDP and CPCM 2 respectively as Gr increases from 0.3 to 0.7 in both cases. The pitch length effect on the thermal performance of TES is found to be negligible. The analysis shows that the horizontal position of TES accrues the lowest charging time for the thorough melting of PCM. © 2023 Elsevier LtdItem Numerical analysis of polyethylene based nano-enhanced phase change material in cylindrical storage system(Taylor and Francis Ltd., 2024) Sheikh, M.I.A.R.; Gumtapure, V.; Ahammed, M.E.Environmental sustainability encompasses various dimensions like waste management, energy conservation, and environmental impact. The use of waste plastic; Linear Low-density polyethylene (LLDPE) as a phase change material (PCM) offers a sustainable solution for energy and the environment. This study investigates LLDPE/ functionalize graphene composites for latent heat storage using a shell and helical coil for effective energy conversion. The simulation is carried out for constant flux and constant temperature heat supply to understand the influence of nano additives and geometrical parameters such as spiral coil diameter (Dc), pitch (Pc), and orientation of storage unit (θ). The result reveals that nano additive influence effectively and reduces the charging time approximately from 20 to 40% for 1–5% of nano-addition. Simulation results reveals that the spiral coil diameter is crucial for melting and heat transmission. The overall melting time is decreased by up to 56% by increasing the spiral coil diameter from 21 to 49 mm for LLDPE while the effect of pitch length variation is found not significant. The constant temperature heating at 160, 250 and 340°C gives effective results for charging time improvement. The geometrical orientations from 0 to 90 degrees report that the horizontal position is the best orientation for energy storage. © 2024 Informa UK Limited, trading as Taylor & Francis Group.