Tubular solar air heater using finned semi-cylindrical absorber plate with swirl flow: Experimental investigation. (1st April 2022)

• Record Type: Journal Article
• Authors: El-Said, Emad M.S.; Abou Al-Sood, M.M.; Elsharkawy, E.A.; Abdelaziz, Gamal B.
• Is Part Of: Solar energy. Volume 236(2022)
• Page Start: 879
• Page End: 897
• Publication Date: 2022-04-01
• Subjects: Swirl flow -- Solar air heater -- Fins -- Thermohydraulic efficiency; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2022.03.054
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: A tubular swirl-flow solar air heater (SF-SAH) with baffles is tested experimentally. Radial baffles enhance SF-SAH performance compared to longitudinal baffles. Increasing the number of radial baffles and air mass flow rate reduces the cost. The proposed SF-SAH achieves thermohydraulic efficiency is about 72.40%. The minimum estimated cost of heat unit production is about 0.0105 $/kW.hr . The maximum effectiveness and exergy efficiency are about 0.6 and 1.3 % respectively. Abstract: In this research, a tubular swirl-flow solar air heater (SF-SAH) with a find semi- cylindrical absorber plate is adopted to enhance its thermohydraulic performance. The proposed SF-SAH is tested with two types of fins: radial and longitudinal. Three sets of fins; 3, 4, and 5 number of fins are tested. Data obtained from the proposed SF-SAH are compared with the plain duct conventional SF-SAH without fins under a typical air flow rate range 0.01–0.050 kg/s and Reynolds number ( Re ) from 7078 to 35190. Results obtained from this study reveal that radial fins enhance SF-SAH performance parameters when compared with the plain heater or heater with longitudinal fins. Also, increasing the number of radial fins and air flow rate enhances SF-SAH efficiency and Nusselt number and reduce the production cost. SF-SAH with five radial fins and air flow rate of 0.050 kg/s results maximum values for thermal and thermohydraulic efficiencies of 76.79%, 72.40%, respectively, Nusselt number of 223.64, and a minimum estimated production cost of 0.0105 $/kW.hr . The maximum effectiveness and exergy efficiency of SF-SAH are obtained with five radial fins and reached about 0.6 and 1.3 % respectively.