Browsing by Author "B.V., B.V."

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Experimental investigation of melting and solidification characteristics in a vertical shell and tube latent heat thermal energy storage system with novel directional flow annular fins
(Elsevier Ltd, 2025) Naik, L.; Gumtapure, V.; B.V., B.V.
In this study the impact of novel directional flow annular fins on the charging and discharging process in a vertical shell and tube latent heat thermal energy storage system (LHTES) with phase change materials (PCM) is examined. Consequently, the tube carrying heat transfer fluid (HTF) is surrounded by five annular fins. To examine the impact of directional flow fins on the thermal performance of LHTES, four novel directional flow fin configurations namely, 1 mm thick solid circular fin, 10 mm thick hollow circular fin - flow of HTF only through the central tube, 10 mm thick hollow circular fin - flow of HTF partially through the central tube and partially through the fin structure, 10 mm hollow circular fin - flow of HTF only through the fin structure were selected. In order to study the LTHES experimentally, three sections are chosen for the location of thermocouples at 0, 120 and 240°. At each sections five thermocouples are located to record the temperature distribution in the PCM. A detailed behavior of melting and solidification cycles are explained by observing temperature variation, accumulative energy and melting fraction during both melting and solidification. Results show that use of directional flow fins decreases melting time by 58.33 % in comparison with conventional fins and solidification time by 50 % of LHTES and allows heat to penetrate deeper through the volume of the PCM more uniformly. Additionally, the thermal efficiency of the LHTES system was found to be 67.4 % during charging and 53.85 % during discharging, validating the significant improvement in energy storage and retrieval performance with directional flow fins in latent heat thermal energy storage system. © 2025
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 Society
Optimized Heat Transfer Rate in Cu/CNT Nano Composite Prepared by Electrodeposition Technique
(Institute of Physics, 2023) Bharathi, K.D.; Rahman, M.R.; Yadav, A.K.; B.V., B.V.; Bhat Panemangalore, P.
Highlights The Cu/CNT nanocomposites are successfully through electrodeposition technique. The composites fabricated with different diameters and concentrations of CNTs. The heat transfer rate measured and optimized CNT diameter in Cu/CNT composites. Optimization of CNT concentration in Cu/CNT composites. SEM micrographic features also carry the signature of in plane CNTs deposition. © 2023 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited
Performance evaluation of novel tapered shell and tube cascaded latent heat thermal energy storage
(Elsevier Ltd, 2021) B.V., B.V.; Nidhul, K.; Gumtapure, V.
Geometric design of the storage system plays a vital role in the enhancement of heat transfer rate and thereby in the advancement of latent heat thermal energy storage (LHTES) technology. The present study numerically compares the heat transfer performance of tapered type shell and tube cascaded latent heat storage (CLHS) model with that of the conventional cylindrical CLHS model with special emphasis on melting rate at the slowest melting portions (bottom) of the shell and tube unit. Thermal properties like transition temperature, latent, and specific heat of the three organic PCMs OM 42, OM 46, and OM 48 have been obtained using differential scanning calorimetry (DSC), and the same is employed in the 2-D numerical simulation carried out using enthalpy-porosity method. Tapered CLHS unit exhibited superior performance owing to stronger natural convective currents demonstrated via streamlines, velocity, temperature and mass fraction contours. In tapered unit, 17.6% higher mean power is obtained for same volume of PCMs in cylindrical unit. In contrast, the mean power of the discharging process for a tapered type is 2.4% lesser than cylindrical type CLHS. The outcomes highlight that the tapered type CLHS model utilizes convective heat transfer, effectively enhancing the melting rate of PCM without any additional structural configurations such as fins. Hence is also economically justifiable for higher energy storage for the same volume compared to conventional cylindrical CLHS units. © 2020 International Solar Energy Society
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 Ltd