Energy storage technology provides a solution to the contradiction between energy supply and demand, as well as the volatility and intermittency of renewable energy. As a representative energy storage system, the coil type energy storage system is of great significance in improving the reliability and cooling economy of building cooling systems. The configuration of coils has a significant impact on the ice storage process and icing rate. This study deals with the experimental and numerical analysis of the influence of different configurations on solidification process. The natural convection and density reversal at 277.15K of water have a significant impact during the cooling process. Therefore, we divide the cooling stage of water into two stages: 283.15K–277.15K and 277.15K–273.15K. Due to natural convection and density reversal of the cooling process, the thickness of the ice layer on the outer surfaces of the upper and lower sides varies unevenly in the horizontal configuration. The phenomenon where the ice layer in the vertical configuration is distributed conical, and the ice layer at the bottom is thinner than the ice layer at the top. As the ice storage process progresses, natural convection decreases from 1.5 × 10⁻² m/s to 2.9 × 10⁻⁴ m/s. Within 210 min, the thickness of the ice layer in the vertical configuration is 2.27 mm thicker than that in the horizontal configuration. This article aims to study the effects of natural convection and density reversal during ice storage, explore the ice storage rate under horizontal and vertical placement, and provide reference value for practical engineering. To be conclusive, the ice storage rate of the vertical configuration increased by 13.33 % compared to the horizontal configuration.