Experimental Investigation of Thermal Performance of Improvement a Solar Air Heater With Metallic Fiber

Abstract

ABSTRACT The current research aims to study the overall performance of a solar air ‎heater ‎integrated system (SAHIs) under the Iraqi weather circumstances throughout the utilization of metallic fiber as a new method in absorbing the heat. Several experiments were conducted using a double pass triangular plate and compared with metallic fiber (SAH) as an absorber surface. These experiments were performed during February, March, and April of 2019 over the air mass flow rate range (0.0043–0.0125 kg/s) and depending upon environmental circumstances. Results evinced that the ultimate daily thermal efficiency of the solar air ‎heater was (63.77%) and (74.2%) with a triangular absorber plate and metallic fiber, correspondingly when using (0.012 kg/s) air mass flow rate and the instantaneous thermal efficiency of (SAH) increased from (30%) to (80%) and (30%) to (95%) when the air mass flow rate was increased from (0.0043 kg/s) to (0.0125 kg/s) and from (0.043 kg/s) to (0.0123 kg/s) for triangular absorber plate and metallic fiber, correspondingly. At an air mass flow rate of (0.012 kg/s), the temperature of the ultimate absorber surface and the outlet of air was (58°C) and (35°C) for triangular absorber plate, respectively and (49°C) and (44.5°C) for metallic fiber correspondingly. Also, the results demonstrated that the daily and instantaneous thermal efficiency of (SAH) with the metallic fiber was higher than that with a triangular absorber plate at the similar air mass flow rate. Additionally, the temperature discrepancy between the absorber surface and the outlet air when employing metallic fiber was less in comparison with the use of triangular absorber plate, and the temperature difference between inlet and outlet air temperature decreased when the air mass flow rate was increased. Moreover, the present study manifested a higher overall thermal efficiency than those obtained by previous studies. Abbreviations: HE: Heat exchanger; SAH: Solar Air Heater; SAHs: Solar Air Heaters; SAHIS: Solar Air ‎Heater ‎Integrated System