Thermal Performance of a Novel Non-Tubular Absorber with Extended Internal Surfaces for Concentrated Solar Power Receivers

A non-tubular prototype cavity receiver absorber with extended internal surfaces (fins) is proposed to enhance heat transfer in Stirling engine-based Concentrated Solar Power systems. There is limited research on the realization of downsized absorbers in terms of their design and manufacturing. The objective of the absorber solution proposed in this paper is to address the issue of inadequate comprehension regarding the impacts of the geometric and flow parameters on thermohydraulic efficiency. These impacts are numerically investigated in a 100 mm long heat transfer channel with a 10 mm x 10 mm section. The prototype absorber is fabricated using a wire electrode-discharging manufacturing approach, and is experimentally investigated using the enthalpy method. Numerical results indicate that heat transfer to the working fluid in the novel absorber can reach 482 W at the reasonable cost of 0.391% pressure drop per 100 mm (air flow at 0.0015 kg/s and 5 bar). In the experimental investigation, the prototype realizes a 1113.033 W heat transfer rate at 8 bar and 12 kg/h. This implies that a non-tubular design with extended internal surfaces can increase the internal surface area to enhance heat transfer while downsizing the volume to reduce heat loss.