Does FFU need constant air volume control or constant speed? Feedback and application condition comparison
The difference between the two control methods
There are two common FFU control methods: constant speed and constant air volume. Constant speed control keeps the fan speed constant. Constant air volume control keeps the air supply volume constant. The control objects of the two are different and the applicable scenarios are also different.
Constant speed control is simple to implement, and the controller runs the fan at the set speed. However, if the filter resistance increases after dust accumulation, the air supply volume of the fan will decrease at the same speed. If the resistance drops after the filter is replaced, the air supply volume may increase.
Constant air volume control adjusts the fan speed through feedback to maintain the target air volume. When the filter resistance changes, the fan will automatically adjust the speed to keep the air volume within the set range. Constant air volume control requires feedback devices, regulation logic and sufficient operating range.
Which control method to choose depends on the project's requirements for air supply stability and operating conditions. Aili Industrial has complete self-research capabilities in FFU control systems and can provide two control solutions: constant speed and constant air volume. For the basic configuration of FFU control and communication, please refer toAili Industrial FFU fan filter unit。
Characteristics of constant speed control
The main features of constant speed control are simple setting, relatively low cost, and direct control logic. The controller operates at a fixed speed and is not affected by changes in filter resistance.
However, the air volume controlled by constant speed will change with the system resistance. After the filter accumulates dust, the air volume gradually decreases. If the project requires high air volume stability, it may be necessary to manually adjust the speed regularly or accept the air volume to change within a certain range.
Constant speed control is suitable for scenarios where the air volume requirements are relatively loose, the filter replacement cycle is short, or the operator can make regular adjustments.
Characteristics of constant air volume control
The main feature of constant air volume control is that the air supply volume is stable and is not affected by changes in filter resistance. When dust accumulates on the filter, the fan automatically increases its speed to maintain the target air volume. After the filter is replaced, the fan automatically reduces the speed to avoid excessive air volume.
Constant air volume control requires a feedback device to measure air volume or related parameters, and the controller adjusts the speed based on the feedback. The control logic is more complex than constant speed, and the cost may be higher.
Constant air volume control is suitable for scenarios where the air volume requirements are strict, the filter replacement cycle is long, or it is inconvenient for operators to make frequent adjustments.
How to check feedback and adjustment logic
The key to constant air volume control lies in feedback and adjustment logic. The feedback method can be a wind speed sensor, differential pressure sensor or other measurement methods. The feedback signal needs to accurately reflect the actual air volume.
The regulation logic needs to be stable and reliable to avoid oscillation or overshoot. The air volume setting value should be adjustable to adapt to different operating modes. The controller should be able to maintain the target air volume within the changing range of filter resistance.
If the feedback is inaccurate or the adjustment logic is unstable, constant air volume control may not achieve the desired effect. The feedback method and adjustment logic should be confirmed when selecting.
How to confirm the scope of work
Constant air volume control requires adequate operating range. When the filter is new, the resistance is low and the fan speed can be lower. The resistance of the filter is high after dust accumulation, and the fan speed needs to be increased. If the fan operating range is insufficient, it may not be able to maintain the target air volume after the filter accumulates dust.
When selecting a model, make sure that the fan can maintain the target air volume within the entire resistance range of the filter from new to replacement. If the operating range is insufficient, you may need to select an FFU with a larger fan capacity or shorten the filter replacement cycle.
How to choose application conditions
Whether to choose constant speed or constant air volume can be judged from the following conditions. The project's requirements for air volume stability; filter replacement cycle and maintenance frequency; whether it is convenient for operators to adjust; control system budget; whether group control and zone adjustment are needed.
If the project requires higher air volume stability or the filter replacement cycle is longer, constant air volume control may be more appropriate. If the project has relatively loose air volume requirements, or there are regular maintenance and adjustments, constant speed control may meet the requirements.
For group control projects, you can refer toFFU/EFU group control touch screen controller andFFU computer group control system understands the control scheme. Aili Industrial has complete self-research capabilities in FFU control systems and can provide constant speed or constant air volume control configurations according to project requirements.
Issues that should be confirmed in advance during project communication
In the FFU control method selection stage, it is recommended to confirm the following with the manufacturer: project requirements for air volume stability; filter replacement cycle; operator maintenance conditions; control method selection; feedback method and accuracy; adjustment logic and working scope; group control and zoning requirements; control costs and operating costs.
If you are choosing FFU control mode, you can visitAili Industrial FFU fan filter unit to learn about the complete machine configuration, you can also refer toFFU/EFU group control touch screen controller andFFU computer group control system to learn about the control scheme, or contact Aili Industrial for control selection support.
in conclusion
FFU constant speed control maintains the speed target, but the air volume may still change when the filter resistance changes. Constant air volume control maintains the target air volume through feedback, which requires the application of feedback, adjustment logic and sufficient working range. Which method to choose depends on the project's requirements for air volume stability, filter replacement cycle and maintenance conditions.
Aili Industrial has complete self-research capabilities in FFU control systems and can provide two control solutions: constant speed and constant air volume. If you need to know more about FFU control method selection, you can visitAili Industrial FFU fan filter unit , you are also welcome to contact Aili Industrial for project support.
