Fig. 1. Schematic of trough reflector-cavity receiver thermal collection system

Fig. 2. Profile structure of the cavity receiver

Fig. 3. Ray path diagram of the heat collection system

Fig. 4. Influence of opening angle α on optical efficiency

Fig. 5. Influence of the radius of arc reflector on optical efficiency

Fig. 6. Influence of different parameters of cavity structure on optical efficiency

Fig. 7. Energy flux distribution of collector tube wall for different cavity structures

Fig. 8. Energy flux standard deviation of collector tube wall for different cavity structures

Fig. 9. Maximum Nu for different collector tubes

Fig. 10. Influence of vertical deviation on optical performance

Fig. 11. Influence of horizontal deviation on optical performance

Fig. 12. (a) Flow chart and (b) physical photo of the test system

Fig. 13. Normalized thermal collection efficiency