Development of paraffin wax as phase change material based latent heat storage in heat exchanger

Energy storage mechanisms enhance the energy efficiency of systems by decreasing the difference between source and demand. For this reason, phase change materials are particularly attractive because of their ability to provide high energy storage density at a constant temperature (latent heat) that corresponds to the temperature of the phase transition of the material. In this study, the melting process of PCM (Phase Change Material) for thermal energy storage is simulated numerically. Melting of PCM which selects paraffin wax with triangular internal walls in rectangular heat exchanger is used. Hot air enters inside the PCM heat exchanger with laminar flow. Three-dimensional model is used and the simulations are performed by using ANSYS (Fluent) 15.0 code. The influence of the melting process for PCM on the heat exchanger performance is analyzed. The modeling results show that, the melting process is increased with increase time stage and fluid mass flow. For all different air mass flow, an increase in the heat transfer rate of air is obtained at the initial stage (in 60 s) followed by a decrease during the following melting process. The numerical analysis also shows that, the enhancement in the heat transfer rate reached 26 W for time 60 s at Re = 2000. To complete the melting process (sensible storage), the time required is 295 s at Re = 2000 and at the heat transfer rate of about 18 W, while it required 485 s at Re = 500 for the heat transfer rate of about 10 W.