Numerical simulations on performance enhancement of a cross-flow latent thermal energy storage heat exchanger

Due to large heat transfer area, compact size and easy handling, cross flow tubular heat exchangers have a potential for a wide range of applications in latent heat energy storage. A two dimensional unsteady-state model is established for this type of heat exchangers contacting phase change materials (PCMs) to study the heat transfer behavior during phase change. Effects of various factors on the charging process are studied, including Stefan number, Reynolds number, thermal conductivity of PCM, arrangement of tubes, and the number of fins (N_fn). The motion of solid-liquid interface is analyzed. The results show that the heat transfer process can be significantly enhanced by the use of fins; The melting time of PCM in a two-fin unit could be reduced by 52.6% compared with a non-fin unit when the thermal conductivity of PCM is lower than 1.0 W/(m·K).