TY - THES A1 - Abdalsalam, Mohannad Mohamad Alsayed T1 - Convective losses inside a cavity of a novel insulating glass flat-plate solar thermal collector N2 - Large-scale solar thermal district heating plants are considered to serve as a renewable alternative in European District Heating systems but their execution imposes widely-considered demand fluctuations and initial cost challenges. Consequently, A novel Insulated glass flat plate solar thermal collector (IGFPC) of low manufacturing cost is introduced to the industry, nevertheless, more research is needed on the collector’s convective heat losses and efficiency. This research focuses on the numerical study of the convective heat losses inside the cavity of the novel IGFPC. The review of other literature concludes the inability to describe the convective losses inside the cavity using other researchers’ correlations due to its large aspect ratio and high operating Rayleigh range so a computational fluid dynamics (CFD) simulation using the Finite Elements Method (FEM) is performed. The research investigates the optimum simulation settings and the optimum mesh size to solve the CFD simulation, in addition to, the governing correlations representing the heat transfer regime inside the cavity. The cavity inclination is studied at angles 0, 15, 30, 45, and 60 degrees heated from below, and Rayleigh numbers ranging from 10^3 to 10^6. It is concluded that the Reynolds stress model (RSM) is the most accurate turbulent model to represent turbulent flow inside the cavity and its results are comparable to other results from the literature. In comparison with the literature review, the simulation results show low convective heat losses at Ra < Ra critical and high convective heat losses at Ra > Ra critical. It is also noted that at a lower Rayleigh number, the cavity experience edge rolls at lower inclination angles and cell rolls at higher inclination angles. Finally, a correlation in the Nusselt Rayleigh domain is derived to be used for numerically calculating overall losses and efficiency for cavities with a high aspect ratio. Keywords: solar district heating, convective heat losses, solar thermal collector, insulated glass flat-plate collector, natural convection, computational fluid dynamics, Nusselt / Rayleigh correlations, Rayleigh number, rectangular cavity, cavity inclination angle Y1 - 2022 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-35881 CY - Ingolstadt ER -