Exergy-energy efficiency and environmental-economic analysis of honeycomb-shaped artificial roughness in solar air heater

Abstract

This research paper explores the exergy-energy efficiency and environmental-economic analysis of honeycomb-shaped artificial roughness in solar air heaters, utilizing a comprehensive approach that integrates computational fluid dynamics (CFD) analysis with experimental validation. The combined algorithm ensures robust optimization by correlating numerical simulations with real-world performance, enhancing the reliability of the findings. Key parameters analyzed include relative roughness height (e/D: 0.03–0.05), pitch (P/e: 8–12), angle of attack (Ø: 90˚–120˚), and Reynolds number (Re: 3000–21000). The maximum thermal efficiency (95.8%) and exergy efficiency (12.4%) were achieved at e/D = 0.04, P/e = 8, and Ø = 120˚. Economic analysis revealed annual costs influenced by Reynolds number, with electricity expenses rising from $2.1 to $626.3 and energy output increasing from 657.3 to 718.2 kWh as Reynolds number increased. This led to a shorter energy payback time, reducing from 9.12 to 8.35 months. The system also demonstrated environmental benefits, with annual carbon dioxide (CO2) mitigation improving from 1367.2 to 1494 kg/year with the increase in Reynolds number, and the environmental-economic parameter rising from $68.3 to $74.7. These findings offer insights for optimizing solar air heater designs, improving economic feasibility, and reducing environmental impact, contributing to sustainable energy policies.