Effect of tapered headers on pressure drop and flow distribution in a U-type polymeric solar absorber

• Main Authors: Bales, C. (Author), Shantia, A. (Author), Streicher, W. (Author)
• Format: Article
• Language: English
• Published: Elsevier Ltd 2022
• Subjects: Discrete model; Flat-plate solar collector; Flow distribution; Pressure drop; Thermo-hydraulic model; U-type solar absorber
• Online Access: View Fulltext in Publisher

 This study inspects the effect of tapered headers on pressure drop and flow distribution in a U-type polymeric absorber with novel tapered headers and lens-shaped absorber strings using a validated thermo-hydraulic model. The model results are compared with those obtained from the literature to attain credibility in the flow distribution trend for the U-configuration. A good agreement between the developed discrete model and comparison cases is found. Moreover, in order to examine the efficacy of tapered headers in more detail, different scenarios are treated in terms of header configuration by applying cylindrical geometry in one or both inlet/outlet headers. The outcomes exemplify that even a slight cone angle of 1.73° in headers can significantly reduce non-uniformity (φmax < 8%) with negligible influence on the total pressured drop. Yet, further reduction in maldistribution (φmax < 5%) can be achieved in U-type absorbers if the tapered outlet header is combined with a cylindrical inlet header in the range of AR ≤ 3.34 and DR ≤ 0.24. In this case, a compromise between additional pressure drop and flow distribution degree should be found. The present study offers a systematic approach for conducting thermo-hydraulic analysis in flat-plate solar collectors with complex absorber compositions and geometries. © 2022 The Authors