Numerical investigation of natural convection solar air heater with different fins shape

• Published in: Renewable energy Vol. 117; pp. 488 - 500
• Main Authors: Hosseini, Seyedeh Sahar, Ramiar, Abas, Ranjbar, Ali Akbar
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2018
• Subjects: Buoyancy force; Mass flow rate; Rectangular; Solar air heaters; Thermal performance; Triangular and elliptical fins; Rectangular; Mass flow rate; Buoyancy force; Triangular and elliptical fins; Thermal performance; Solar air heaters
• ISSN: 0960-1481; 1879-0682
• DOI: 10.1016/j.renene.2017.10.052

In this paper, natural convection of air in solar air heaters with rectangular, triangular and elliptical fins is numerically investigated. Finite volume method is used to discretize the governing equations in the three dimensional domain, the Realizable K-ε model is used for closing the turbulence equations and Business model is utilized for simulating buoyancy force. Effect of inclination angle on mass flow rate and thermal performance of solar air heaters is studied. The results showed that Optimum angles to obtain the highest mass flow rate occur in the range of 45o<β<60o for triangular and elliptical fins and 50o<β<75o for rectangular fins. Also the reverse flow angle of inclination, beyond which the solar air heater is not able to deliver hot air is obtained for different fin shapes. The results showed that rectangular fin lead to the narrowest range of applicable inclination angles (45o<β<90o) and the widest range belongs to the elliptical fins with the range of 33.75o<β<90o. Results revealed that the solar air heater with rectangular fins has the best thermal performance and yet the lowest mass flow rate. Also the results revealed that thermal performance of solar air heaters with rectangular fins is slightly higher than that of heaters containing two other fin shapes in the same dimensions. •Solar chimneys with different longitudinal fins are studied numerically.•Inclination angle and solar radiation intensity Effects are investigated.•Heater with rectangular fins has the lowest applicable inclination angle range.•Higher performance and lower mass flow rate is seen in case of rectangular fins.