Optimization on a cylindrical Fresnel lens and its validation in a medium-temperature solar steam generation system

• Published in: Renewable energy Vol. 134; pp. 1332 - 1343
• Main Authors: Ma, Xinglong, Zheng, Hongfei, Liu, Shuli
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.04.2019
• Subjects: Cylindrical Fresnel lens; Optimal transmittance; Solar concentrator; Solar steam generation; Optimal transmittance; Cylindrical Fresnel lens; Solar concentrator; Solar steam generation
• ISSN: 0960-1481; 1879-0682
• DOI: 10.1016/j.renene.2018.08.075

This paper presents an optimization on cylindrical Fresnel lens and validates it by using a medium-temperature solar steam generation system. The optimal transmittance condition of prism is used for designing the edge-prism of cylindrical Fresnel lens. A method that used for estimating Fresnel lens' real transmittance is given, by which the real transmittance is figured as 81.6%. Finally, a 20 m2 area solar concentrator is set up as heat source for steam generator. Experimental test is carried out under two operating gauge pressures of 0.2 MPa and 0.5 MPa. The results show that the average collection efficiency of concentrator is about 0.48 and 0.44, correspondingly under gauge pressures of 0.2 MPa and 0.5 MPa. The experimental data is fitted as a linear relationship, in which the intercept efficiency is about 63%. Finally, a comparison with traditional solar steam generation system is undertaken, including structure, concentration performance and price. Cylindrical Fresnel lens system has relatively higher collection efficiency, easy-tracking and cost-effective etc. While the stable working time is about 4.5 h, which is shorter than parabolic trough concentrator's 6.2 h. Thus, enhancing its stable working time will be one of the research priorities in the future. •Optimize the structure of cylindrical Fresnel lens to maximize its transmittance.•The real transmittance of Fresnel lens is measured as 81.6% by CCD testing.•A SSG system with Fresnel lens is set up and tested under different conditions.•A comparison to PTC and CPC types SSG systems is presented.