Investigation of the effect of eccentricity and shell diameter on the charging performance of erythritol for thermal energy storage

Abstract

This study investigates the effect of changing eccentricity and shell diameter on the charging performance of latent heat thermal energy storage systems (LHTES). A three-dimensional numerical model was developed to simulate the melting process of erythritol as a phase change material (PCM) in a horizontal double pipe heat exchanger. The results demonstrate that increasing eccentricity significantly enhances charging performance, with optimal relative eccentricity values between 0.6 and 0.7 across various shell diameters. Under optimal conditions, all shell diameters showed at least a 32 % improvement in charging efficiency, reducing charging time by a minimum of approximately 4 h. Larger shell diameters showed greater sensitivity to eccentricity changes, with charging time reductions up to 43 % for a 133 mm shell. The study also reveals that eccentricity promotes more uniform temperature profiles and accelerates the charging process by enhancing natural convection. These findings provide valuable insights for optimizing latent heat thermal energy storage designs, particularly for larger-scale applications.