Experimental and numerical analysis of frost formation in household refrigerators: Evaluating the effects of fin removal in front of the return duct

Frost formation on evaporators in household refrigerators remains a critical challenge that affects energy efficiency and temperature stability. The accumulation of frost on the evaporator fins obstructs airflow, reduces heat transfer efficiency, and leads to increased energy consumption and inconsistent compartment temperatures. While previous studies have explored general strategies for frost mitigation, the specific effect of fin removal in front of the return duct has not been thoroughly investigated. In this study, both experimental and numerical methods are employed to analyze frost formation and thermal performance under two configurations: Case 1 with fins and Case 2 without fins in front of the return duct. Most of the airflow passing through the return duct primarily undergoes heat exchange at the bottom section of the evaporator before flowing upward along the wall, making the lower fin crucial for heat exchange. The experimental results showed that removing the fins reduced frost thickness by approximately 2 mm (13 %) near the return duct after 18 h, while maintaining airflow for a longer duration. However, this modification led to a rise of up to 2 °C in fridge compartment temperatures due to reduced heat transfer efficiency. Numerical simulations using an Eulerian multiphase flow model and a custom User-Defined Function (UDF) validated the experimental findings, showing a reduction in frost volume fraction in critical areas. This study provides novel insights into the trade-offs between frost reduction and thermal performance, demonstrating for the first time how fin removal affects airflow dynamics and frost formation mechanisms. The findings offer a pathway for optimizing evaporator designs to develop energy-efficient and frost-resistant refrigeration systems.