A Comprehensive Comparison between Square Ducts and Circular Ducts: How to Choose the More Suitable Ventilation Duct?
In the design of ventilation systems, the selection of duct shape directly affects project efficiency and cost. As the two mainstream types, square ducts (with rectangular or square cross - sections) and circular ducts have significant differences in performance and application scenarios. The following is a comparative analysis from core dimensions to help decision - makers optimize the selection plan.
I. Comparison of Structure and Sealing Performance
Circular ducts are formed using an integrated spiral locking or welding process, creating a streamlined duct without edges. This structure minimizes air flow resistance. Meanwhile, as the joints are equipped with factory - preinstalled air - tight connectors (usually with double - layer rubber gaskets), they can withstand a positive pressure of 3000 Pa and a negative pressure of 5000 Pa. The overall air leakage rate is significantly lower than that of square ducts. In contrast, square ducts are assembled from metal sheets. The flange or insert strip connection methods are prone to form leakage points at the corners, and the reliability of manual sealing is weaker than that of standardized circular pipe fittings.
II. Differences in Airflow Efficiency and Energy Consumption
The aerodynamic advantages of circular ducts enable them to perform outstandingly in long - distance air transportation. Experimental data shows that under the same air volume, the pressure loss of circular ducts is about 20% - 30% lower than that of rectangular ducts. This means that the fan power can be reduced by more than 15%, and the long - term energy - saving benefit is significant. However, due to the right - angle structure of square ducts, it is easy to generate turbulent flow. Especially in high - velocity airflow scenarios, the eddies at the corners will additionally increase the system resistance, and the efficiency loss needs to be compensated by increasing the fan power.