Investigation of melting and energy storage performance of PCM in a flat plate solar collector considering novel dendritic fin design and GO+MXene hybrid nanoparticles

Abstract

In this study, the melting and energy storage characteristics of a phase change material (PCM) vessel integrated into a conventional flat-plate solar collector (FPSC) were numerically investigated using novel modifications. Dendritic fins have a diameter of d = 1 mm and are at different pitch ratios (P) to each other. Based on this situation, different pitch ratios of P/d = 1.5, 2.0, and 2.5 were used in the dimpled fin design, and this novel fin structure was utilized in research. As another novel method, graphene oxide (GO) + MXene hybrid nanoparticles (HyNP) incorporated in RT35 HC PCM at volumetric condition of phi(vol.) = 2.0% and 6.0% were brought forward. Solar radiation supplied a heat flux of q" = 1000 W.m(-2) on the system boundary. According to the results, pure PCM performed the best melting and energy storage characteristics compared to hybrid nano-PCM (HyNPCM) due to its lower viscosity. When phi(vol.) = 2.0% and 6.0% HyNPCMs were used, the melting time increased by 1.0% and 1.98%, respectively. In the cases with dimpled dendritic fins, it was observed that the melting time decreased as P/d decreased, and Case 7 (P/d = 1.5) achieved complete melting 11.1% earlier than Case 4 (without dimpled fins) and 76.2% earlier than Case 1. However, since the available volume for PCM storage decreased as P/d decreased, the highest energy storage was observed in Case 13 (P/d = 2.5), with a value of 2517 kJ.m(-1). Acquired stored energy amount was higher than Case 1, 4, 7, and 10 at the rate of 3.45%, 1.51%, 1.38%, and 1.23%, respectively. The results obtained from this study will pave the way for the use of dendritic fin structures in thermal energy storage (TES) systems.