Assessment of the heat transfer efficiency of perforated louvered fins for improved drainage

Abstract

To address the inherent drainage challenges of louvered fin and flat tube heat exchangers (LFFTHXs) when used as evaporators, this study presents an innovative louvered fin design with perforations that significantly improve drainage efficiency while reducing fin material usage. Traditional LFFTHXs, despite their superior heat exchange capacity compared to fin-and-tube heat exchangers (FTHXs), suffer from poor drainage of condensate and defrosting water, leading to problems such as metal corrosion, airflow blockage, reduced thermal comfort, and increased energy consumption. Our proposed solution, the perforated fin, especially the models with two combined holes (LF-2CH), shows a significant improvement in drainage performance compared to conventional designs, as confirmed by theoretical analysis and numerical simulations. In addition, we have systematically studied the air-side flow and heat transfer characteristics of different configurations, revealing that 18° and 24° louver angles in the LF-2CH models can enhance heat transfer rates by up to 20.9 % and 18.0 %, respectively, at the lowest fan power compared to conventional louvered fins. By elucidating the impact of louver angle on airflow dynamics and thermal wake patterns, we highlight the LF-2CH models as optimal for evaporator applications, combining improved thermal-hydraulic performance, efficient dewatering capacity, and reduced fin material consumption to provide a compelling advancement in heat exchanger technology.