Analysis of fluid flow and heat transfer in the novel liquid volumetric plated cavity receiver

Abstract

The article mainly focuses on the study of thermal performance of liquid volumetric plated cavity receiver which includes the flow characteristics of heat transfer fluid and estimation of heat losses. Due to higher heat capacity, liquids are considered more suitable heat transfer fluid than air. However, it is difficult to use liquid as heat transfer fluid (HTF) in the conventional air volumetric receivers, therefore a plated volumetric receiver is proposed, as it can heat the fluid within the volume of the receiver. The plated receiver consists of a parallel arrangement of rectangular cells suspended in an enclosure. Each cell is enclosed by two large rectangular metallic plates joined together, creating a hollow space between them with inlet and outlet nozzles. The incoming solar radiation is absorbed by outer surface of the cell and transferred to the HTF. Large absorbing surface area and large contact area between the plates and HTF is the key feature for avoiding hot spots on the cell’s surfaces. Numerical analysis is carried out for molten salt flow inside the cells and air flow in the cavity. The results show a uniform distribution of flow (with Re = 212) resulting into no hotspots on the receiver surface. Local heat transfer coefficient is estimated to be maximum and minimum in the high and low flux regions, respectively. The thermal efficiency of the receiver is calculated as 90.76%. The cell thickness and plate size of the receiver is 6 mm and 100 mm × 50 mm, respectively.