Open Access

ARTICLE

Effect of Fin Spacing on Frost Growth and Airflow Dynamics in ASHP Evaporators

Zhengqing Zhang^1,2,3,*, Xiaojun Yuan², Hui Wu²

1 School of Mechanical and Electrical Engineering, China University of Mining and Technology, Xuzhou, 221000, China
2 Zhejiang Zhongguang Electrical Co., Ltd., Lishui, 323000, China
3 School of Automotive Engineering, Shandong Jiaotong University, Jinan, 250357, China

* Corresponding Author: Zhengqing Zhang. Email:

(This article belongs to the Special Issue: Fluid Mechanics & Thermodynamics in Renewable Energy and HVAC Systems)

Fluid Dynamics & Materials Processing 2025, 21(12), 2927-2943. https://doi.org/10.32604/fdmp.2025.071115

Received 31 July 2025; Accepted 21 November 2025; Issue published 31 December 2025

Abstract

Frost accumulation on the evaporator fins of air source heat pumps (ASHPs) severely degrades heat transfer performance and overall system efficiency. To address this, the present study employs computational fluid dynamics (CFD) to investigate how fin spacing influences frosting behavior, emphasizing the coupled evolution of frost thickness, density, airflow, and temperature distribution within fin channels. Results reveal that fin spacing is a key parameter governing both the extent and rate of frost growth. Wider fin spacing enhances frost accumulation, with a final frost mass of 6.41 g at 12 mm, about 71.8% higher than at 4 mm. In contrast, narrower spacing suppresses frost formation by accelerating airflow. The frost layer exhibits a distinct two-stage growth pattern: at 12 mm spacing, the early-stage average thickness growth rate reaches 0.021 mm/min, nearly 4.3 times that at 4 mm. Frost density follows similar initial trends across different spacings but diverges later due to thermal resistance and airflow variations.

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Keywords

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