Verma, PrashantRishav Kumar2019-11-132019-11-132019-08http://krishikosh.egranth.ac.in/handle/1/5810135173Latent heat thermal energy storage (LHTES) technique helps to reduce the problems related to discrepancy between supply and demand of energy in every aspects of time, space and severity hence it has acquired a great deal of research mainly focussing on the conservation of energy and environment. In the present work, melting characteristics of a lauric acid in a horizontal shell and finned tube type storage unit is studied numerically and experimentally. The low thermal conductive nature of phase change materials (PCMs) have pre-eminently constricted the advantage of this storage system for its various applications hence an attempt has been made to provide the finned tube in the storage container to enhance the heat transfer rate between heat transfer fluid (HTF) and PCM. It has been observed that not much research is carried out to investigate the effect of eccentric arrangement of a finned HTF tube on the melting performance of the PCM experimentally hence different eccentric finned tube position is also considered. The smaller length of fins are considered which covers 33 % of an annulus region for determining the enhancement due to the natural convection effects in the eccentric annulus of storage unit. To investigate the effect of finned tube installed at different eccentric distances on the rate of heat transfer, the melting rate of PCM in an annular is analysed with different angles between fins in bottom annulus of storage unit at different eccentric positions of inner tube through experimental and enthalpy- porosity based numerical two dimensional model in Ansys Fluent software. The results obtained through numerical calculations have been found in agreement with experimental results. The enhancement in the melting rate of PCM at three different eccentric values for inner tube from the centre of outer tube is examined i.e. for e= 12 mm, 18 mm and 24 mm apart from concentric configuration (e= 0 mm) and the effect of inlet temperature of HTF for maximum eccentric and concentric annulus is also explored. Results shows that the melting rate is 21 % higher at the maximum eccentric annulus as compared to those in concentric configuration due to enhanced domination area for natural convection effects, which also increases the uniformity in temperature distribution in PCM and this eccentric behaviour for the enhancement of melting performance is effectively achieved in the fin configuration having angle 60° between the fins in the bottom annulus. It has been also concluded that the increase in Stefan number, enhances the melting rate of PCM irrespective to the eccentric position of inner tube, besides the rate of enhanced natural convection effects due to increase in eccentric distance of inner tube in vertically downward direction is further augmented by 10°C rise in temperature of HTF during the melting process. It is also found that heat storage rate in an eccentric annulus is 18.7 % higher in comparison to concentric annulus.ennullThesis