Experimental study of new solar air heater design

ABSTRACT

The suitable design is the most important key to a cost-effective solar air heater. Although there are many techniques that have been proposed to improve the solar air heaters’ performance by means of different turbulence promoters, they cannot ensure a compromise between the cost and the effectiveness. The aim of this study is to find simple and tolerable solution to get rid of the inconvenience resulting from the widely adopted heat-transfer-enhancement techniques by providing an optimized solar air heater design. The proposed design consists of a slightly curved smooth flow channel with an absorber plate of convex shape. A prototype of a curved solar air heater of 1.28 m² collector area was built and tested under summer outdoor conditions in Biskra (Algeria). The performance was evaluated in terms of thermal and effective efficiency for mass flow rates of 0.0172, 0.029, and 0.0472 kg/sm². It is observed that the overall efficiency of this solar air heater is considerably higher in comparison with the efficiency range of the conventional smooth flat plate heaters reported in the literature for similar operating conditions.

KEYWORDS:

• Experimental investigation
• rectangular curved duct
• solar air heater
• solar energy
• thermo hydraulic performance

Acknowledgments

The authors would like to express their gratitude to Pr. Mahmoud Omari, Dr. Azeddine Belakehal, Mr. Abdelkrim Baissi, the engineers and technicians in the Department of Mechanical Engineering. The authors also wish to express their thanks to the reviewers for the helpful comments and the suggestions for improving the manuscript.