Initial Analysis on the Novel Spiky Central Receiver Air Pre-heater (SCRAP) Pressurized Air Receiver

Performance outlook of the SCRAP receiver

“…It was found that the effect of heliostat size/facet size has a notable effect on the flux distribution along a spike [2]. As the spike tip points towards the solar field it experiences the highest flux.…”

“…Due to the geometry of the spike tip a strong cooling effect of the impinging air stream onto the tip surface (end cap in Figure 2) -as it changes the flow direction by 180 • -is envisaged. The heat transfer model introduced in [2] describes the internal heat transfer within a spike. In the model the spike tip is treated as a black box requiring an averaged Nusselt number (Nu) and flux input.…”

“…A simplified heat transfer model was introduced in [2]. The flow model is meshed linearly, however, due to the return flow configuration, thermal interaction occurs between upstream and downstream nodes far apart (e.g.…”

“…The SCRAP receiver is intended as an external metallic tubular pressurized air receiver, with purpose of pre-heating an air stream to up to 800 • C upstream of a gas turbine's combustion chamber (or secondary receiver) [2].…”

Optical and thermal performance of bladed receivers

“…This configuration of cool tips, hot interiors is common to a range of high-efficiency receiver concepts, including this ANU/Sandia concept [2] (lateral tubes), the NREL concept [4] (longitudinal tubes) as well as the 'pyramid' receiver of Garbrecht et al [10] and the spiky 'SCRAP' receiver of Lubkoll et al [11], and is also the object of the 'volumetric effect' sought after for open air receivers, where flow also takes a longitudinal path, and where outer surfaces are expected to have lower temperatures than the inner surfaces, yielding lower radiative heat loss [12,13]. …”