Investigation of the Pressure Effects in the Preparation of Macro Encapsulated Phase Change Materials for High Temperature Energy Storage Systems

Encapsulated phase change materials (PCM) are interesting high energy density solutions to store thermal energy, though there has been little investigation for PCMs at high temperature. The aim of this work is to create a PCM with high durability at high temperature with capsuling the PCM. It is a substance which melts and solidifies at an early constant temperature, and is capable of storing and releasing large amounts of energy when undergoes phase change.KNO3 served as a PCM for high thermal energy storage, while diatomite acted as the carrier matrix to provide the structural strength and prevent of its leakage. It was found that KNO3 could be retained 65 wt. % into pores and on surfaces of diatomite without the leakage of melted KNO3 from the shape stabilized –composite (SS-C) PCM. The green circular sheet with the diameter of 26 mm and the height of 4.5 mm was obtained at 45 MPa via a hydraulic machine. Diatomite was used as supporting material to prepare the phase change diatomite with different operating temperatures.As the articles shown there are only one pressure worked on. By changing of the pressure, we could find the best pressure point for building a KNO3/diatomite PCM.In this study KNO3/diatomite PCM with 65 wt. % of KNO3 was chosen by the article and the effect of different type of pressures such as 100, 200 and 300 bar on the 15 mm pellet with the width 5mm was seen with an Infrared camera. Analysis of the results show that the pressure plays key rule and has significant effect on PCM performance.