| Energy has always been an important factor in human survival. With the development of worldwide industrialization process, a lot of fossil energy has been consumed and environmental issues are becoming increasingly serious. How to make better use of existing fossil fuels and to achieve sustainable social and economic development by using the more new energy resources,which has become the subject of growing concern. There are several energy resources such as solar, geothermal and industrial waste heat which have intermittent and stability characteristics. It is difficult to have a good match between the supply and demand for this type of energy, resulting in lower energy use. Using energy storage technology can solve the energy supply and demand mismatch well. Phase Change Materials(PCMs) for latent heat energy storage has become the most widely energy storage technology.Analysis deeply on the heat transfer progress of PCM plays a significant role in designing an effective phase change thermal storage device. Given the effect of natural convection in phase transition process, the phase change heat transfer problems is a class of strongly nonlinear problems, leading to a complicated solution. The numerical method is usually applied to solve this problem. In this paper, the model of Solidification/Melting is used to simulate the melting and solidification of paraffin wax outside the tube. The influence of the different initial temperature for phase change material on the phase change process is discussed. The effect of the heating temperature for tube on the phase change is discussed. The result shows that natural convection is the main reason for the irregular solid-liquid interface in the phase change process. During the phase transition process, natural convection accelerates melting while delayed solidification.Most of PCMs have the low thermal conductivity which resists the performance of heat transfer in latent storage system. The main way to increase the heat storage efficiency is to using the Finned-tube. This paper carries out a numerical simulation of phase change material’s melting process outside heating tube with fins. The solid-liquid interface is computed. Detailed parametric investigations of tube fins are performed to find the effect on melting time. The results showed that decreasing the gap of fins resulted in an appreciable increase in overall thermal performance. Increasing the fin thickness and conductivity only gave a slight improvement. |
