A comparison study on melting inside the rectangular and curved unit with a vertical heating wall

Efficient and rational use of thermal energy requires the design and development of suitable and cost-effective latent heat storage systems. In this study, a novel curved thermal storage unit is put forward and its thermal behavior has been numerically compared with the traditional rectangular PCM-based thermal storage unit. The solid-liquid interface evolution, liquid flow pattern and temperature distribution are presented. Transient Nu at the heating wall and full melting time are also calculated. The numerical results show the high impact of the enclosure geometry on melting and nature convection. A reduction of 30.6 % in thermal storage time has been achieved by changing the unit from rectangular to curve. Moreover, parametric studies are conducted to assess how thermal performance of the units is affected by the heating wall temperature and PCM thermal conductivity. Correlations encompassing a wide range of parameters are developed in terms of full melting time. Results indicate that proportion of full melting time reduced for the curved unit is almost a constant value and does not vary significantly with these factors. All these may be very helpful for the design of more efficient thermal storage units.