Numerical and experimental study on the performance of a thermal energy storage in a solar building

Building can provide a comfortable indoor environment with a huge energy consumption. Utilization of solar energy coupling with thermal energy storage is the key topic in the energy-saving of the building. The latent heat storage technology with phase change materials is a promising means to improve the utilization of renewable energy. Nevertheless, its broad application will be limited due to the low thermal conductivity of material. This paper focused on the heat transfer performance of a phase change material for a thermal energy storage building. The main contributions are as: an experiment system of thermal energy storage has been designed, the mathematical model of the numerical calculation has been established and verified, and the effect of operating conditions for multi-parameters on the melting process of the phase change material has been studied. Paraffin is used as phase change material and water as heat transfer fluid. The melting behavior of PCM stored in the outer tube and the inner shell region has been studied when heated water passes through the inner tube. The results show that the melting performance of PCM is the best for the inclination angle of 30°. The inlet water temperature has an obvious influence on melting property. The melting times are 775 min, 690 min, 620 min, 565 min and 515 min, respectively, for five different inlet water temperatures. The inlet flow rate has a weak influence on melting time. The research results can provide reference for pipeline design and heat storage efficiency of latent heat storage system in the future.