Title: Energy and exergy analysis of a solar air collector with evacuated tubes under different flow and reflector configurations

Authors: Nitin Panwar; Rajesh Attri

Addresses: Department of Mechanical Engineering, J.C. Bose University of Science and Technology, YMCA, Faridabad, Haryana – 121006, India ' Department of Mechanical Engineering, J.C. Bose University of Science and Technology, YMCA, Faridabad, Haryana – 121006, India

Abstract: This study investigates the energy and exergy performance of a solar air collector (SAC) integrated with evacuated tubes under varying air flow rates and reflector configurations. Experiments conducted from 08:00-18:00 h showed outlet air temperatures up to 105.2°C. Energy efficiency ranged between 35-71%, while exergy efficiency varied from 2.16-5%. Exergy input, output and loss averaged 104.6, 3.0 and 101.6 kJ/kg, respectively. Efficiency decreased near midday but improved later. Overall, the reflector-assisted high-flow system demonstrated superior thermal and exergy performance, highlighting its potential for sustainable and efficient solar air heating applications.

Keywords: evacuated tube; solar air collector; thermal performance; exergy; flow rates.

DOI: 10.1504/IJEX.2026.153923

International Journal of Exergy, 2026 Vol.50 No.1, pp.15 - 27

Received: 16 Oct 2025
Accepted: 16 Nov 2025
Published online: 08 Jun 2026 *

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