Thermal energy storage system using stearic acid as a phase change material

The thermal performance and phase change stability of stearic acid as a lat ent heat energy storage material has been studied experimentally. The therm al performance and heat transfer characteristics of the stearic acid were t ested and compared with other studies given in the literature. In the prese nt study, parameters such as transition times, temperature range and propag ation of the solid-liquid interface as well as the effect of the heat flow rate on the phase change stability of stearic acid as a phase change materi al (PCM) were studied. The experimental results showed that the melting sta bility of the PCM is better in the radial direction than in the axial direc tion. The variation in the melting and solidification parameters of the PCM with the change of inlet water temperature is also studied. We observed th at while the heat exchanger tube is in the horizontal position, the PCM has more effective and steady phase change characteristics than in the vertica l position. The heat storage capacity of the container (PCM tube) is not as good as we expected in this study and the average heat storage efficiency (or heat exchanger effectiveness) is 50.3%. This indicates that 49.7% of th e heat is actually lost somewhere. (C) 2001 Elsevier Science Ltd. All right s reserved.