Investigation of the effects of different parameters of phase change material on heat transfer for waste heat recovery systems

Increasing energy demands and limited resources have increased interest in designing energy storage systems for industries. Latent Heat Storage (LHS) systems could be promising solution technique for energy storage problem. Phase Change Materials (PCMs) as a LHS system is a well-known solution technique due to high energy storage capacity, chemical stability and low vapor pressure properties at low operating temperatures. These properties have made PCMs promising energy storage materials for many applications such as electronic cooling, waste heat recovery and many different fields. The aim of this study is numerically investigate heat transfer effectiveness of a regenerative heat exchanger using PCMs for different parameters. The parameters used in the study were determined as hot fluid Re number (Re=400, 800, 1200, 1600); hot fluid inlet temperature (Thot,inlet=40, 60, 70, 80℃) and different PCMs types (SP70, RT100, RT60). ANSYS Fluent software has been used for computational fluid dynamics (CFD) analysis. The results indicate that increasing Reynolds number of the hot fluid gradually in range of Re=400-1600 caused an increase of 17.2% in efficiency of heat storage of PCM material. Increasing inlet temperature of the hot fluid gradually from 40℃ to 80℃ caused an increase of 15.8% in the efficiency of heat storage of PCM material. Furthermore, among different types of PCMs, RT60 has performed the highest heat storage performance. It has been evaluated that, with the data obtained from this study, heat exchangers with higher heat transfer effectiveness can be designed and more efficient energy storage systems can be designed by using different types of phase change materials.