Fig. 1. Physical model of critical interception CPC without light escape. (a) Physical model of high criticality interception; (b) physical model of low criticality interception

Fig. 2. Schematic diagram of S-CPC vertical incident ray tracing

Fig. 3. Flowchart of the C' point coordinate solving program

Fig. 4. Experimental diagram of small hole imaging

Fig. 5. Experimental and theoretical values of spot positions on absorber at different moments of time. （a） 13：00—14：00； （b） 14：00—15：00

Fig. 6. Comparison of optical efficiency of different concentrators

Fig. 7. Energy flux density at different incidence angles. (a) 0°; (b) 15°; (c) 30°; (d) 45°

Fig. 8. Flowchart for calculating solar radiation harvesting

Fig. 9. Amount of radiation collected by different concentrators