Performance improvement of baffle-type solar air collector based on first chamber narrowing. (May 2019)

• Record Type: Journal Article
• Authors: Hu, Jianjun; Liu, Kaitong; Guo, Meng; Zhang, Guangqiu; Chu, Zhongliang; Wang, Meida
• Is Part Of: Renewable energy. Volume 135(2019)
• Page Start: 701
• Page End: 710
• Publication Date: 2019-05
• Subjects: Solar air collector -- Performance optimization -- First chamber narrowing -- Numerical simulation -- Experimental verification; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2018.12.049
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: This paper proposes a novel idea to optimize thermal performance of baffle-type solar air collector by narrowing the first chamber through rearranging the baffles in the collector. The collector with five chambers divided by four baffles was investigated numerically and experimentally, and the mechanism of performance improvement was revealed by flow and heat transfer analysis. The simulation results show that the width of first chamber has significant influence on thermal efficiency, while has little influence on pressure drop. The maximum thermal-efficiency growth rate can be achieved when the width of the first chamber is 200 mm with the total chamber size of 2000 mm × 1000 mm × 120 mm, and the value is up to 16.90% compared with the model with evenly distributed baffles during the Reynolds number ranges from 1.8–5.5 × 10 3 . A test rig was developed at the ratio of 1:0.5 to the numerical model. Four collector models were studied under three working conditions, and effectiveness of this method is verified. The results show that the first-chamber narrowing method has relatively stable optimization effect with a thermal-efficiency growth rate ranges from 9.73% to 16.10% in the experiment. It means that this method is not sensitive to scale change and has certain adaptability. Highlights: Thermal performance of baffle-type collector improved by narrowing the first chamber. There exists optimal narrowing width for a certain scale baffle-type solar air collector. First-chamber narrowing influences the efficiency but not the flow resistance. First-chamber narrowing is not sensitive to scale change and working conditions.