Number of views: 875 Author: AILI Industrial Release time: 2027-02-06 Source: Ai Li Industrial
The circulating air handling unit should be selected according to the indoor sensible heat, moisture load and circulating air supply requirements assigned by the design. Equipment cooling, personnel, and building envelope are common inputs, but loads already carried by the MAU or other systems should not be included again.
In the same factory building, the cooling system of process equipment may take away some heat, and the fresh air system may also bear some heat and moisture treatment. The circulating unit should handle the remaining and clearly assigned load. It is necessary to explain the actual heat released by the equipment into the room, rather than directly using the sum of the electrical capacities of all equipment.
Equipment heat must be distinguished between heat dissipation entering the room and heat taken away by independent cooling; project design conditions and actual use periods must be adopted for personnel and enclosures; air tasks must describe circulating air volume, air supply status, and filtration division. The three sets of inputs correspond to different sources and cannot be mixed together for estimation. For the division of labor between the circulation unit and MAU, please refer toHow does the fresh air task of the clean room MAU correspond to the process exhaust?。
The nameplate power of process equipment includes shaft power, heat taken away by cooling water and heat dissipated to the environment, which cannot all be included in the sensible heat load of the room. Some equipment removes heat through process cooling water or independent exhaust air. Only the air heat actually entering the room belongs to the air conditioning load. Equipment operating conditions and simultaneous usage factors also affect peak loads.
How to check the heat dissipation of equipment in semiconductor, panel display, advanced packaging and other industries, please refer toHow to check the sensible heat and moisture load of the equipment in the air-conditioning box of the advanced packaging workshop? andWhat process environment requirements need to be collected for the air-conditioning box of semiconductor clean factory?。
Indoor moisture load comes from personnel breathing and sweating, process moisture dissipation, ground moisture evaporation and enclosure penetration. If the circulation unit is responsible for dehumidification, it is necessary to check the dehumidification capacity of the coil and the supply air dew point. If the wet load is already handled by the fresh air system, the circulating unit may only need to bear the sensible heat load.
The difference between dehumidification capacity and cooling capacity can be referred toHow to calculate the dehumidification capacity of air conditioning box from the difference in air moisture content? . For the relationship between supply air dew point and moisture control, please refer toWhat role does the supply air dew point play in the selection of fresh air air conditioning boxes? . Unclear calculation of wet load may lead to a smaller selection of cycle units or higher dehumidification energy consumption.
The air volume of the circulation unit is usually determined by the number of air changes, air flow organization and sensible heat load. When the air volume is too large, the coil and filter cross-sections increase, and the fan energy consumption increases; when the air volume is too small, the room temperature uniformity and cleanliness may be affected. The supply air temperature difference and air supply status must also match the coil capacity.
How to determine the air supply 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? . How to select the type of surface cooler according to the air inlet and outlet conditions, please refer toHow to select the type of air conditioner cooler according to the air inlet and outlet conditions? . The division of labor between the circulation unit and FFU can be combinedFFU fan filter unit understand.
When production is shut down or part of the equipment is shut down, the load on the circulation unit may change significantly. In addition to checking the maximum capacity, it is also necessary to check the regulation method, coil water supply and low-speed operation. A large circulating air supply volume does not mean that all air volumes must be treated as outdoor air.
For the relationship between partial load regulation and fan efficiency range, please refer toWhy should we check the efficiency range when selecting air-conditioning box fans? . For the adjustable range of coils and humidification equipment at low load, please refer toWhat control objectives should be clarified when selecting a constant temperature and humidity air conditioning box?。
Organize the sensible heat, moisture load and circulating air volume of each area into a load table, and then determine the air supply status and unit configuration through design. If there is no equipment heat dissipation data, the missing items should be marked and the data should be filled in to avoid using rough estimates as guaranteed values. The load table should indicate the source, working conditions and simultaneous use conditions to facilitate review during subsequent changes.
The sequence of functional sections and the number of coil rows will change with the load, please refer toOn what basis should the sequence of functional sections of the air conditioning box be determined? andWill the greater the number of coil rows in an air-conditioning box, the greater the cooling capacity? . When it comes to mixing the circulation unit and MAU air supply, please refer toHow to consider the incorporation of MAU fresh air into the air inlet status of the circulating unit?。
Aili Industrial can match the fan, filtration and structure of the circulating unit based on the load attribution table, and simultaneously confirm the circulating power and available pressure when matching the FFU to reduce repeated configurations. 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 interfaces and operating points of circulation units, FFU and MAU can be aligned in the same package; non-standard air volume can be adjusted according to regional load.
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; terminal particle filtration can be combinedHEPA/ULPA filter confirmation; when it comes to gaseous pollution control, you can communicate separatelyChemical filter solutions. The specific load distribution, unit performance 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.
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Can the equipment nameplate power be directly used as room sensible heat load?
cannot. Part of the equipment power is taken away by the process cooling water or exhaust air, and only the heat that actually enters the room is included in the air conditioning load.
Does the circulating unit need to bear the wet load?
It depends on the system division of labor. If the wet load is already handled by the fresh air system, the circulating unit may only need to bear the sensible heat load, as determined by the design allocation.
Can Aili Industrial help check the circulation unit load?
The load attribution table and circulating air volume can be combined to match the unit configuration. The specific load distribution needs to be confirmed by the system design.
Check items |
Confirm key points |
Check items |
Confirm key points |
|---|---|---|---|
Equipment heat |
Distinguish between heat entering a room and being removed independently |
Personnel and containment |
Design conditions and actual use period |
air mission |
Circulating air volume, air supply status and filtration division |
wet load |
People, technology and containment |
Operating range |
Maximum Capacity and Minimum Operating Point |
load meter |
Source, operating conditions and simultaneous use conditions |
