To solve the problem of poor melting consistency for the horizontal shell-and-tube latent heat thermal energy storage (LHTES) unit. An up-under cascaded arrangement structure is proposed

and a three-dimensional LHTES unit model (Case 1

Case 2-n

Case 2-N) is established in the paper. Performance evaluation indices such as phase change process

complete melting time

average thermal energy storage rate

and exergy performance of the three models are compared and analyzed

and the superior performance of the novel structure is expounded in detail. The results illustrate that Case 2-N has a shorter period of melting time and a higher average thermal energy storage rate than Case 2-n and Case 1. The complete melting time of Case 2-N reduces by 36.2% and 19.4% compared with Case 1 and Case 2-n

and the average thermal energy storage rate improves by 20.1% and 11.8% compared to Case 1 and Case 2-n. Moreover

complete melting uniformity and temperature field uniformity also have a noticeable improvement for Case 2-N compared to Case 2-n and Case 1. The complete melting time difference of the upper and lower sector regions for Case 2-N is only 4.6%. In addition

Case 2-N has advantages in minimizing entropy generation number and improving exergy efficiency. This paper can provide direction guidance and theoretical reference for the high-efficiency operation of horizontal shell-and-tube LHTES units.