Energy and Exergy Analysis of a Flat-Plate Solar Air Heater Artificially Roughened and Coated with a Novel Solar Selective Coating

Abstract

Enhancements in heat transfer, and consequently the thermohydraulic performance of solar air heaters (SAHs), are necessary to widen and optimize their use in many applications such as solar drying or heating buildings. In this investigation, two techniques were used. A novel solar selective coating combined with broken arc ribs roughness was employed with a SAH and the evaluation of the energetic and exergetic performance was applied under four airflow working conditions compared to a smooth absorber SAH coated with the same coating. The results revealed that the Nusselt number of roughened SAH with the new coating exhibited a notable improvement compared to a smooth absorber SAH and a roughened SAH without a coating. Furthermore, the thermal efficiency increased with the increase in the air flow rate and the maximum rise was 18.8% compared to a smooth SAH. The highest increase in exergy was 51.6% with minimum values of exergy destruction and improvement potentials. In brief, the roughened SAH with 4% CNTs/CuO-black paint under the airflow rate of 0.0244 m3/s (condition C) exhibited the best energetic and exergetic performance.

Performance of New Absorber Coating Strategy in Solar Air Heaters: An Experimental Case Study

“…doi: 10.5829/ijee.2022. 13 Solar energy is the most affordable renewable energy that has been extensively used to produce green thermal *Corresponding Author Email: hadi.farzan@bam.ac.ir (H. Farzan) energy. Numerous techniques have been introduced to harvest solar thermal energy, and SAHs are the most affordable and simple collectors among these techniques [1,2].…”

“…A comparison between a conventional SAH and a SAH using artificial roughness and absorber coating materials illustrated that the equipped SAH had higher performance and outlet temperature around 7.5% and 13.5 o C, respectively. Abdelkader et al [12,13] used CNTs/CuO black paint as coating materials in a flat plate solar air heater using ribs roughness. Using these methods caused thermal performance to increase by 18.8% compared to a conventional SAH.…”