Enhancing Corrosion Resistance and Heat Transfer Performance of Fin-Tube Heat Exchangers for Closed-Type Heat-Source Towers by Superhydrophobic Coatings

Abstract

Heat-source towers are essential components in heat pump systems, pivotal for achieving energy efficiency. Enhancing corrosion resistance and heat transfer performance for heat-source towers is important but challengeable. For solving this problem, this study aims to introduce a novel superhydrophobic (SHP) coating applied via a one-step electrodeposition method to enhance both corrosion resistance and heat transfer performance of fin-tube heat exchangers in closed-type heat-source towers. The superhydrophobic nature of the coating is validated by contact angle measurements, while its structural integrity and chemical composition are confirmed through various methods i.e., X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. Corrosion resistance tests indicate a significant improvement, with the coating showing a corrosion current density of 1.400 × 10−6 A/cm2 and a low-frequency modulus |Z|0.01 Hz of 1.50 × 10⁴ Ω cm2 after 30 days in a 15 wt.% calcium chloride solution at 0°C. Additionally, heat transfer experiments demonstrate a 42.5% increase in heat transfer efficiency compared to uncoated fins under identical conditions, which present the significant heat transfer performance of the presently developed SHP coating. The key contribution of this research lies in the development and application of a novel SHP coating that significantly enhances the performance of heat-source towers. Moreover, the present findings suggest that implementing this SHP coating can substantially improve the durability and efficiency of heat-source towers, supporting the advancement of more sustainable building infrastructures.