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Subject: Mechanical Engineering × End date: 2024 × Start date: 2020 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Investigation on the melting performance of phase change material in a horizontal modified shell and tube thermal energy storage using longitudinal fins
    (G.B. Pant University of Agriculture and Technology, Pantnagar, District Udham Singh Nagar, Uttarakhand. PIN - 263145, 2022-03) Baldev Kumar; Verma, Prashant
    Energy conversion is an essential aspect of technology advancement, and hence its efficient generation and use are important in today's scenario. In present scenario, there is a large gap between demand and supply, and it is difficult to meet the current energy requirement. Thermal energy storage devices enable us to attain energy demand while simultaneously minimizing pollution. This modified geometry having semi-circular shaped shell with finned tube has not been studied much for the melting performance of the phase change material in recent available literature. Hence it has been decided to investigate the melting performance of PCM numerically and experimentally for semi-circular shell having finned tube latent heat thermal energy storage (LHTES) system. Enhancement of melting performance of lauric acid in a semi-circular shell with three longitudinal fins attached to the inner tube has been done for a two-dimensional numerical model in Ansys fluid fluent. The temperature obtained at different locations of shell from the numerical data has also been validated with experimental results. Since the phase change materials have low thermal conductivity so adding fins is one of the effective performance enhancement techniques used in the analysis to enhance the melting rate. Therefore, three different fin arrangements at different fin angles (= 60º, 90º, 120º) have been investigated for the melting performance of the PCM. It has been found that the melting rate of PCM for fin angle of 90º is higher, as compared to other fin arrangements. PCM melting performance is also investigated for different values of inlet temperature of heat transfer fluid for fin angle of 90º. It is observed that on increasing the Stefan number improves the melting rate of PCM in the semi-circular shell finned tube LHTES system. The results for a semi-circular shell with a fin angle of 90º for the LHTES system are found better as the thermal energy storage rate of finned tube LHTES system is 0.27 kW, which is 68.75 % higher as compared to an un-finned tube LHTES system. The semi-circular shell with finned tube LHTES melts the PCM completely in 1800 seconds (30min) which is 34.78 % less in time than the un-finned tube LHTES system. The thermal energy stored in PCM for the shell with finned tube LHTES system is 409.32 kJ, which is 11.06 % more than that of un-finned tube LHTES for the same time duration of 2700 sec. The thermal energy storage efficiency of semicircular with finned tube LHTES unit has been found 7 % higher than that of un-finned tube LHTES.