Effects of receiver parameters on the optical performance of a fixed-focus Fresnel lens solar concentrator/cavity receiver system in solar cooker

Abstract

To facilitate building integration with solar cooker for household, a solar cooker based on a fixed-focus Fresnel lens solar concentrator/cavity receiver system was proposed. To increase the system optical efficiency, the cavity receiver with bottom reflective cone was used as a fixed receiver. Expecting to optimize the system and receiver of better optical performance, the effects of receiver parameters on it were studied. To evaluate the effects, a significance test of key factors was conducted. Comparative analysis of fixed-focus food cooking system was undertaken. The analysis shows that average optical efficiencies using cavity receiver with bottom reflective cone of spherical, cylindrical, conical are 72.23%, 68.37% and 76.40%, respectively, while that of their corresponding conventional cavity receivers are 68.49%, 31.91% and 74.61%. The former significantly increased 3.74%, 36.46% and 1.79%, respectively. Moreover, cavity receiver with bottom reflective cone angle 90° is able to hold a higher amount of incoming energy from concentrator, compared to other three angles. Increasing the bottom reflective cone reflectivity and cavity receiver surface absorptivity can improve optical efficiency. In addition, the cavity receiver surface absorptivity and concentrated sunlight incidence angle have the most significant influence on the optical efficiency and flux uniformity, respectively. The conical cavity receiver with bottom reflective cone is the most suitable one for system. This work is expected to be useful for further optimization of solar concentrator/cavity receiver system.