If the total air volume of the air conditioning box is insufficient, should you check and measure it first or increase the speed first?

When the total air volume of the air conditioning box is insufficient, you should first confirm the measurement method, measurement points and operating conditions, then check the fan working point and system resistance, and finally evaluate whether to adjust the speed. If the measurement is inaccurate, the air valve is throttled or the filter is clogged, directly increasing the speed may increase energy consumption and noise without solving the cause.

First prove that the air volume is indeed lower than the target under the same working conditions

Check whether the units, air conditions and measurement boundaries of the design value and the actual measured value are consistent. The local air outlet wind speed cannot directly represent the total air volume, and the measurement section is too close to an elbow or the air flow is uneven, which will also affect the results. After confirming the reading, check the filter differential pressure, valve position, external static pressure and actual rotational speed to look for resistance or drive deviation.

When the air volume units are inconsistent, you can refer toHow to convert the air volume units of air conditioning box in m³/h, L/s and CFM? . For the relationship between fresh air and total air supply, please refer toHow to calculate the fresh air volume and total air supply volume of the air conditioning box separately? . How to determine the design air volume, please refer toIs the air supply volume of the air conditioning box determined based on the number of air changes or the cooling and heating load?。

What does a measurement review include?

The measurement review should cover the representativeness of instruments, sections, methods, units and measuring points. The measurement section of the air duct should avoid elbows, reducers and valves, the pitot tube or anemometer should be operated according to the method, and the air density and pressure standards should be consistent. If the measurement cross-section is not representative, the reading may be low or high.

Pressure caliber is easy to confuse, please refer toWhat is the difference between static pressure, total pressure and static pressure outside the air conditioner 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? . Before measurement, it should be confirmed that the system is in stable operation, and the air valve opening and filter status are completely recorded.

Changes in system resistance are often mistaken for insufficient fans.

Dust accumulation on the filter, unopened air valve, blocked air duct, coil resistance, closed muffler and fire damper, etc. will all cause the total air volume to decrease. Directly increasing the speed may increase the fan power and noise, but the increase in air volume is limited. The filter pressure difference, valve position and system resistance should be checked to find the link where the resistance increases.

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 configure the primary and medium-efficiency filters in stages, please refer toHow to configure the primary-efficiency and medium-efficiency filters of air-conditioning boxes in different stages? . What needs to be considered when arranging the filter section before and after the fan? Please refer toWhat needs to be considered when arranging the filter section before and after the fan?。

There must be a basis for adjusting the fan operating point and speed

After confirming that there are no abnormalities in the system, that the measurements are reliable, and that adjustments are still needed, professionals can evaluate the motor load, fan speed limit, noise, and filter burden. After adjustment, you need to re-measure. You cannot just look at the control percentage becoming larger. If the original system resistance exceeds the design, system or selection modifications should be discussed first.

How to check the fan efficiency range, please refer toWhy should we check the efficiency range when selecting air-conditioning box fans? . For the driving conditions of DC fans, please refer toWhat driving conditions need to be matched when using a DC fan in an air-conditioning box? . For comparison between backward-inclined and forward-inclined fans, please refer toHow do the backward-inclined and forward-inclined fans compare when used in air conditioning boxes?。

When do system or selection corrections need to be made?

If the fan is already at the allowable upper limit, the system resistance is significantly higher than the design, the air duct layout is unreasonable, or the filter configuration changes, simple speed regulation may not be a suitable solution. Modification of air ducts, replacement of fans, adjustment of filter area or zoning scheme should be compared. Before equipment modification, lock in unchangeable conditions. Please refer toWhat unchangeable conditions should be determined first for non-standard customization of air-conditioning boxes?。

How to choose between complete machine replacement and partial component update, please refer toHow to choose between complete replacement of air conditioning box and partial component update? . How to choose between combined and integral types, please refer toHow to choose between combined and integrated air conditioning boxes?。

Aili industrial supporting equipment

When feedback to Aili Industrial about insufficient air volume, the measurement method, rotation speed, pressure difference and filtration status are provided to help distinguish measurement, system and equipment matching issues. Aili's industrial manufacturing end covers independent R&D and production of motors and fans, control systems, sheet metal, air filters and complete machine assembly. The fan working point, filter resistance and control interface can be corresponded in the same set of supporting materials; non-standard air volume can be adjusted according to on-site resistance conditions.

Product form can be viewedAir handling unit andFan box page; clean air supply package can be combinedFFU fan filter unit andEFU equipment end fan filter unit verification; multiple equipment linkage can understandMatching method of FFU computer group control system ; terminal particle filtering can be combinedHEPA/ULPA filter confirmation; when it comes to gaseous pollution control, you can communicate separatelyChemical filter solutions. The specific air volume performance, adjustment plan and delivery scope still need to be verified based on the corresponding configuration data and on-site working conditions. The actual effect is subject to on-site air volume balance and performance test results.

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

Related questions and answers

If the total air volume is insufficient, can the fan speed be directly increased?
Not recommended. You should first confirm that the measurement is reliable, the damper opening and system resistance are normal, and then evaluate the speed adjustment. Otherwise, energy consumption and noise may increase without solving the cause.

If the wind speed at the local air outlet is low, does it mean that the total air volume is insufficient?
uncertain. The local air outlet wind speed is affected by the outlet form and branch distribution and cannot directly represent the total air volume. It should be measured at a representative section.

Can Aili Industrial help troubleshoot insufficient air volume?
It can be combined with measurement records, fan operating points and system resistance to assist in judgment. Specific processing must be carried out by on-site professionals in accordance with equipment instructions.

Related articles

1. How to troubleshoot if the air conditioner fan is running but there is no obvious air supply?

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

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

4. Why should we check the efficiency range when selecting air-conditioning box fans?

Key points for selection and acceptance inspection