melting time

thermal storage

microplastic particles

mri images

Journal of Energy Storage

Freezing process inside an annulus zone was reported numerically in this article. The domain is filled with paraffin (T m =82 °C) and for improving thermal features, nanoparticles were added. Fins with various sizes and positions were applied and two levels for fraction of nanomaterial were utilized. Exergy drop is main outputs of current research and contours in three time stages were reported. Unsteady phenomena were reported with considering structure grid. Average values of significant parameters were extracted as function of time. Non-zero values of velocity show the impact of buoyancy force. For verification, experimental outputs of published paper have been utilized. Exergy drop (Xd) declines with rise of time because of reduction of temperature. The value of Xd decrease about 91.14% when time increases from 1 to 15 min for case 8. The geatest case win lowest needed time is case with thinner fins over the outer wall and it needs 17.86 min to reach complete solidification. Inclusion of alumina in to paraffin makes freezing time to decrease about 11.7%. Changing the position of fins from inner to outer causes the freezing rate to increase about 14.45%.

Numerical modeling of energy storage unit during freezing of paraffin utilizing Al2O3 nanoparticles and Y-shape fin