Comparison of Different Heat Exchanger Tube Designs used in Latent Heat Thermal Energy Storage Systems - a Numerical Study

The present article deals with the fundamental understanding of the melting behaviour of a phase change material based on basic structures of different heat exchanger tube designs (tubes with longitudinal- or transversal fins as well as a wire frame) for enhancing the heat transfer. Three-dimensional transient numerical simulations are performed using the ANSYS Fluent 14.5 software. The numerical results of the melting process for the different design cases are compared. A special focus of the study lies on the rate of load change. A comparison of three heat exchanger tube designs has shown that during the first phase of melting the highest charged power is given by the design with the wired frame. But the heat exchanger tube with the longitudinal fin design shows in comparison to the other design cases a more constant power over a longer time period. Based on the numerical results the tube design with longitudinal fins should be the preferred design.