How to determine the rated air volume of the high-efficiency filtration section of the air-conditioning box?

The high-efficiency filtration section of the air-conditioning box should be configured based on the total design air volume, the rated air volume of a single filter under agreed conditions, the number of parallel connections, and the uniformity of air flow. The rated air volume needs to correspond to the efficiency and resistance data. It cannot be calculated only based on the outer frame size, nor can the ratings of all filters be simply added up and then the distribution ignored.

Calculate parallel sharing first, and then check the actual cross section

For example, if the total air volume is 10,000 m³/h, four parallel filters are planned to be used. When evenly distributed, each filter will bear 2,500 m³/h. It is also necessary to confirm the efficiency, initial resistance and allowable use range of the selected model at the air volume. If the layout makes a certain unit bear more air volume, even if the total amount is sufficient, the part may exceed the agreed conditions.

For single data, the grade, rated air volume, resistance and usage restrictions should be written; for parallel arrangement, the quantity, installation frame, wind direction and front and rear equalization space should be written; for system calibration, the initial and final resistance budget, sealing and maintenance inspection conditions should be written. Only by putting the three items in the same table can the air volume configuration of the high-efficiency filtration section be based. Whether the high-efficiency filter is placed inside the machine or at the end will affect the air volume distribution and inspection conditions. Please refer toShould the high-efficiency filter of the air-conditioning box be placed inside the machine or at the end of the air supply?。

The rated air volume cannot be calculated only based on the outer frame size.

High-efficiency filters with the same outer frame size may have different rated air volumes with different filter material grades, pleat densities, and structural forms. Only configuring according to the size and quantity of the outer frame may easily lead to high surface speed, increased resistance or decreased efficiency in actual operation. The rated air volume should be derived from the performance data of the selected model, and the resistance and efficiency should be checked at the corresponding air volume.

How to select the filter level according to the inlet air conditions, please refer toHow to select the air conditioning box filter grade based on the inlet air conditions? . How to grade and configure the initial effect and medium effect, please refer toHow to configure the primary-efficiency and medium-efficiency filters of air-conditioning boxes in different stages? . The upstream protection of the high-efficiency filter section will affect the dust holding capacity and resistance growth of the high-efficiency filter.

The number of parallel connections must leave a margin for air flow distribution.

When multiple filters are connected in parallel, the airflow distribution across the box cross section may be uneven. The local wind speed may be higher near the fan outlet, box corner or access door. If there are no flow equalization measures or the installation frame layout is unreasonable, some filters may reach the upper limit of resistance in advance or their efficiency may decrease.

The mixing section and equalization space will affect the cross-sectional wind speed distribution, please refer toHow long is the air mixing distance required in the mixing section of the air conditioning box? . The influence of the wind speed facing the coil can be referred toWhat impact does the coil head-on wind speed have on heat exchange and water entrainment in the air conditioning box? . The high-efficiency filtration section also needs to pay attention to the surface velocity distribution, not just the average surface velocity.

The system resistance should be checked separately according to the initial resistance and final resistance.

The initial resistance of the high-efficiency filter changes with the model and air volume, and the final resistance corresponds to the state when it needs to be replaced. The fan pressure budget usually needs to cover the final resistance and cannot be calculated based on the initial resistance alone. If the upstream filter of the high-efficiency filtration section is insufficiently protected, the resistance of the high-efficiency filter will rise faster.

For filter classification configuration and pressure difference monitoring, please refer toHow to configure the primary-efficiency and medium-efficiency filters of air-conditioning boxes in different stages? . What functional segments does internal resistance include? Please refer toWhat functional segments should be included in the internal resistance of the air conditioning box? . How to establish the fan pressure budget, please refer toHow is the total pressure of the air conditioning box fan determined by the internal resistance and external demand?。

Operation adjustment should not only focus on the total air volume

When multiple fans or variable air volume are operating, it should be confirmed that the distribution of each branch and each filter position is still within the allowable range. Calculation is especially required when filters of different specifications are mixed. For field replacements, substitutes should be verified for full performance conditions and should not be considered equivalent simply because they are similar in size and grade label.

When the total air volume is insufficient, check the measurement first or increase the speed first. Please refer toIf the total air volume of the air conditioning box is insufficient, should I check and measure it first or should I increase the speed first? . How to calculate fan energy consumption by operating period, please refer toHow to calculate the energy consumption of air conditioning box fans separately according to operating periods?。

Aili industrial supporting equipment

Aili Industrial can check the parallel layout around the high-efficiency filter and box installation frame. When confirming the information, please provide the total air volume, adjustment range and allowable resistance. Aili Industrial has air filter manufacturing capabilities and can jointly confirm the filter size, grade, headwind speed, initial resistance and installation method with the air-conditioning box structure; the manufacturing end covers independent research and development and production of motors and fans, control systems, sheet metal, air filters and complete machine assembly. The high-efficiency filtration section and box interface can be aligned in the same package.

Product form can be viewedAir handling unit andFan box page; terminal particle filtration can be combinedHEPA/ULPA filter confirmation; clean air supply package can be combinedFFU fan filter unit andCheck the fan filter unit at the EFU equipment end ; when it comes to gaseous pollution control, you can communicate separatelyChemical filter solutions. The specific rated air volume, filtration efficiency and delivery scope still need to be verified based on the corresponding filter data and on-site working conditions. Actual results are subject to on-site leak detection and particle test results.

Submit project parameters:https://ailigy.com/contactus.html

Related questions and answers

Can the air volume of the high-efficiency filtration section be estimated based on the outer frame size?
cannot. Filters of the same size have different filter material grades and structures, and the rated air volume may be different. The performance data of the selected model should prevail.

If multiple filters are connected in parallel, is it enough to add the rated air volume?
not enough. Also check whether the airflow distribution is uniform. High local wind speed may cause some filters to fail prematurely.

Can Aili Industrial help check the air volume of the high-efficiency filtration section?
The parallel configuration and resistance conditions can be checked based on the total air volume, filter material and box structure. The specific plan needs to be confirmed based on product data and on-site working conditions.

Related articles

1. Should the high-efficiency filter of the air-conditioning box be placed inside the machine or at the end of the air supply?

2. How to configure the primary-efficiency and medium-efficiency filters of air-conditioning boxes in different stages?

3. What functional segments should be included in the internal resistance of the air conditioning box?

4. How is the total pressure of the air conditioning box fan determined by the internal resistance and external demand?

Key points for selection and acceptance inspection