Introduction Performance Analysis of a Pancake Absorber - Helical Heat Exchanger for a Solar Concentrator

This paper presents an analysis of the performance of a pancake absorber with a helical heal exchanger for use with point focus solar concentrating collectors. Th e principal difference between this type of absorber and most other concentrating solar collector absorbers is that the intensity of concentrated radiation monotonically increases from the inlet to the outlet of the heat exchanger tube. A performance expression for this absorber type and ra.diation distribution is deriued and u ed to calculate thermal performance for seueral different absorber designs. Thermal performance for these design. is then calculated using a performance analysis based on the simplifying assumption that the heat exchanger tube is uniformly irradiated and the two performances are compared. The comparison indicates that the different radiation dist ribution assumptions lead to di fferent absorber design choices. In particular, the simplifying assumption ouerstates thermal losses for increases in absorber size.