Views: 0 Author: Site Editor Publish Time: 2025-04-25 Origin: Site
EC (Electronically Commutated) fans are commonly used in various systems to meet specific airflow and pressure requirements. By configuring EC fans in parallel or series, different system performance demands can be addressed. However, the two configurations significantly affect the system’s performance. Below is a detailed comparison and practical application guide.
| Configuration | Definition | Core Goal |
|---|---|---|
| Parallel | Multiple fans are connected side by side, working together | Increase airflow (at the same pressure) |
| Series | Multiple fans are connected in sequence, with the airflow passing through each one | Increase pressure (at the same airflow) |
In a parallel configuration, multiple fans are connected to the same duct system. The pressure remains the same while the airflow is summed.
Performance Curve:The individual fan performance curve is Q-H, and after parallel connection, the total curve shows the airflow summing under the same pressure (horizontal axis adds up, vertical axis remains unchanged).
System Resistance Curve:The working point is where the system resistance curve intersects with the parallel fan curve. Here, total airflow Qtotal=Q1+Q2Q_{\text{total}} = Q_1 + Q_2Qtotal=Q1+Q2, and total pressure Htotal=H1=H2H_{\text{total}} = H_1 = H_2Htotal=H1=H2 (assuming identical fans).
Airflow:The system resistance increases with more fans in parallel (due to duct friction and local resistance). The actual total airflow is typically 80-90% of the theoretical value. For instance, if a single fan provides 1000m³ airflow, two parallel fans may achieve 1800m³ rather than 2000m³.
EC Fans with Overload Protection Feature and Weatherproof Design can help offset these losses by supporting smart speed adjustments.
Pressure:The pressure remains the same as a single fan’s pressure. The ability to overcome resistance depends on the operating point. In parallel configurations, pressure is determined by the system resistance curve and fan performance.
Automatic Load Balancing: EC controllers dynamically adjust fan speeds to prevent "wind stealing" (when one fan dominates due to excessive resistance).
Partial Load Efficiency: At low demand, only some fans operate, maintaining high energy efficiency.
Parallel fan configurations are ideal for large airflow, low pressure systems such as:
Data center ventilation
Commercial building HVAC fresh air systems
Large warehouse ventilation
Cleanroom air exchange
Redundant design for backup (N+1 configuration)
In a series configuration, fans are connected end to end, where the airflow passes sequentially through each fan. The airflow remains the same, but the pressure increases.
Performance Curve:The individual fan performance curve is Q-H, and after series connection, the total curve shows the pressure summing under the same airflow (vertical axis adds up, horizontal axis remains unchanged).
System Resistance Curve:The working point is where the system resistance curve intersects with the series fan curve. Here, total pressure Htotal=H1+H2H_{\text{total}} = H_1 + H_2Htotal=H1+H2, and total airflow Qtotal=Q1=Q2Q_{\text{total}} = Q_1 = Q_2Qtotal=Q1=Q2.
Pressure:The total pressure is generally less than twice the pressure of a single fan (due to airflow disturbance from the previous fan, duct resistance, etc.). For example, if a single fan produces 500Pa, the total pressure in a series configuration may be around 900Pa rather than 1000Pa.
Airflow:The airflow remains the same as a single fan's airflow, but the series configuration helps overcome higher resistance, such as in long ducts or high static pressure environments.
Pressure Coordination: Speed synchronization ensures the pressure output of the fans matches (e.g., slightly higher speed of the first fan to reduce backflow).
Overload Protection: Built-in pressure sensors monitor the pressure difference between fans, adjusting speed to prevent motor overload if system resistance increases.
Series fan configurations are best for high-pressure, low airflow systems like:
Industrial dust removal systems (high resistance, long distances)
High-rise building smoke exhaust systems (overcoming vertical duct static pressure)
Cleanroom filtration systems (high resistance filters)
Long-distance ventilation systems (mining, tunnels)
Industrial Backward Centrifugal Fan is a suitable option for overcoming high static pressures in such applications.
| Parameter | Parallel | Series |
|---|---|---|
| Airflow | Significantly increased | Same as one fan |
| Pressure | Same as one fan | Significantly increased |
| System Resistance Impact | High resistance leads to airflow loss | High resistance leads to pressure loss |
| Energy Efficiency | High (partial load operation) | Lower (requires full power) |
| Control Complexity | Requires multi-fan coordination | Requires inter-stage pressure matching |
| Typical Applications | Ventilation, cooling, large airflow systems | High-pressure airflow, high-resistance systems |
Fan Consistency: Choose identical models to prevent efficiency loss.
Duct Design: Ensure even airflow distribution from the parallel fans to avoid turbulence.
Control Strategy: Use EC group control features to dynamically start/stop or adjust fan speeds.
Stage Matching: Avoid excessively high pressure at the first fan to prevent overpressure at the second fan's inlet.
Heat Management: Enhance heat dissipation for closely arranged series fans (consider independent ducts or liquid cooling).
Protection Mechanisms: Use pressure sensors to prevent overload in subsequent fans.
Requirement: Total airflow of 20,000 m³/h, pressure of 500 Pa.
Solution: 4 EC fans in parallel (each fan’s airflow: 5500 m³/h, pressure: 500 Pa).
Outcome: Actual airflow of 21,000 m³/h (95% efficiency), saving 30% in energy via dynamic speed matching.
Requirement: Airflow of 5000 m³/h, pressure of 1200 Pa (due to HEPA filter resistance).
Solution: 2 EC fans in series (each fan’s airflow: 5000 m³/h, pressure: 700 Pa).
Outcome: Actual pressure of 1350 Pa, with an 8% efficiency loss between stages.
EC fans, with features like smart speed control and efficient energy management, can significantly improve system performance in both parallel and series configurations.
For example, EC Backward Centrifugal Fan is perfect for optimizing airflow and pressure control.
When designing an EC fan system, it is crucial to consider the airflow-pressure curve, system resistance, and cost factors, with a preference for simulation or actual testing to validate the configuration.
