The required airflow of an industrial air cooler is mainly determined by the size of the space, ceiling height, required air changes, heat load, and ventilation conditions. Choosing a unit only by floor area can result in too little or too much airflow.
For a factory, warehouse, or large workshop, a practical starting point is to calculate the building volume and then determine how much air needs to be circulated or replaced each hour.
1. Calculate the Workshop Air Volume
First, calculate the total air volume of the area that needs cooling:
Air Volume (m³) = Length (m) × Width (m) × Average Height (m)
For example, a workshop is:
Length: 50 m
Width: 30 m
Average height: 8 m
The workshop volume is:
50 × 30 × 8 = 12,000 m³
This 12,000 m³ figure is the basis for the airflow calculation.
For buildings with different ceiling heights, use the average height rather than simply using the highest point.
2. Determine the Required Air Changes per Hour
The next step is to determine how many times the workshop air should be replaced or circulated each hour.
The basic formula is:
Required Airflow (m³/h) = Workshop Volume (m³) × Air Changes per Hour (ACH)
For example, if the 12,000 m³ workshop requires 20 air changes per hour:
12,000 × 20 = 240,000 m³/h
The calculated requirement is therefore approximately 240,000 m³/h.
However, there is no single ACH value that applies to every factory. The appropriate value depends on the heat load, building openings, production process, ventilation arrangement, climate, and cooling objective.
3. Consider the Factory Heat Load
Air changes provide a useful starting point, but they should not be the only consideration.
A workshop with welding machines, furnaces, compressors, dryers, or other heat-producing equipment may require a different airflow arrangement from a warehouse with relatively low internal heat generation.
Pay particular attention to concentrated heat sources such as:
- Welding stations
- Industrial furnaces
- Injection molding machines
- Compressors
- Motors
- Ovens and dryers
- Hot production lines
If heat is concentrated in specific areas, the cooling system may need higher airflow or targeted air distribution in those zones.
4. Calculate the Number of Industrial Air Coolers
Once the required total airflow has been estimated, divide it by the rated airflow of the selected industrial air cooler.
Number of Units = Required Total Airflow ÷ Airflow per Unit
For example:
Required airflow: 240,000 m³/h
Airflow per cooler: 20,000 m³/h
Then:
240,000 ÷ 20,000 = 12 units
The preliminary calculation therefore indicates approximately 12 industrial air coolers.
In practice, the final quantity may change after considering airflow distribution, installation locations, heat sources, building structure, and the actual operating conditions.
5. Do Not Calculate Airflow from Floor Area Alone
A common mistake is to say:
One industrial air cooler can cool X square meters.
This approach can be misleading because the same floor area can have very different air volumes.
For example:
Factory A
1,000 m² × 4 m = 4,000 m³
Factory B
1,000 m² × 10 m = 10,000 m³
Although both factories have the same floor area, Factory B contains 2.5 times more air volume.
Therefore, industrial air cooler airflow should be evaluated using building volume, not floor area alone.
6. Consider Ceiling Height
Ceiling height becomes especially important in large industrial buildings.
A high-ceiling workshop has a greater air volume, but that does not necessarily mean all of the air needs to be treated in exactly the same way.
The design should consider where workers are located and where heat accumulates.
For ceiling-mounted industrial air coolers, important factors include:
Mounting height
Air discharge direction
Air velocity at working level
Distance between units
Roof and structural obstructions
Production equipment layout
The objective is effective air movement in the occupied zone rather than simply achieving a high total airflow figure.
7. Consider Existing Ventilation
Evaporative industrial air coolers introduce cooled air into the workshop. The warm air and moisture need a path to leave.
Therefore, the required airflow should be evaluated together with the existing ventilation system.
Check:
Exhaust fans
Roof vents
Windows
Doors
Wall openings
Natural ventilation
Existing air extraction systems
If the building has poor air exchange, increasing the number of evaporative coolers alone may not provide the expected result.
8. Consider Temperature and Humidity
For evaporative cooling systems, ambient humidity has a direct effect on achievable cooling performance.
In a hot and dry environment, the incoming air can absorb more moisture, generally allowing greater evaporative cooling.
In a hot and humid environment, the available evaporative cooling potential is lower.
Therefore, an airflow calculation should be accompanied by local climate data, particularly:
Summer outdoor temperature
Relative humidity
Wet bulb temperature
Seasonal operating conditions
A high airflow figure cannot compensate indefinitely for unsuitable humidity conditions.
9. Check Airflow Distribution, Not Just Total Airflow
Two factory cooling systems can have the same total airflow but produce different results.
For example, 200,000 m³/h distributed evenly across a workshop may provide better working-zone cooling than the same airflow concentrated in one area.
Before finalizing the industrial air cooler layout, consider:
Cooler → Airflow path → Working area → Exhaust path
Avoid placing the discharge directly against:
Large walls
Tall machinery
Storage racks
Structural columns
Other obstructions
The airflow should have a reasonably clear path through the occupied area.
10. Example of an Industrial Air Cooler Airflow Calculation
Consider a factory with:
Length: 60 m
Width: 40 m
Average height: 8 m
Workshop volume: 19,200 m³
Design air changes: 20 ACH
The required airflow is:
19,200 × 20 = 384,000 m³/h
Suppose the selected industrial air cooler provides 24,000 m³/h per unit.
The preliminary number of units is:
384,000 ÷ 24,000 = 16 units
So, 16 units would be the starting point for the airflow calculation.
The final equipment quantity and layout should then be checked against the factory's heat load, ventilation openings, humidity, installation height, and airflow distribution.
11. What Information Is Needed for an Airflow Calculation?
When requesting an industrial air cooler recommendation, provide more than the factory's floor area.
Useful project information includes:
Factory length
Factory width
Ceiling height
Cooling area
Outdoor summer temperature
Relative humidity
Main heat sources
Number of workers
Production equipment
Existing exhaust fans
Doors and windows
Available water supply
Power supply
Desired operating period
These details allow the airflow requirement to be assessed according to the actual factory conditions.
Industrial Air Cooler Airflow Calculation: Key Formula
For a preliminary calculation, remember these two formulas:
Workshop Volume = Length × Width × Average Height
Required Airflow = Workshop Volume × Air Changes per Hour
Then:
Number of Air Coolers = Required Airflow ÷ Airflow per Unit
These formulas provide a useful starting point for industrial air cooler selection. They should not replace a complete HVAC or ventilation design when the project has complex heat loads, strict temperature requirements, or specialized environmental conditions.
Final Considerations
Calculating the required airflow for an industrial air cooler is more than multiplying the factory area by a fixed number. Workshop volume, air changes, heat load, humidity, ventilation, ceiling height, and airflow distribution all affect the final equipment selection.
For a large factory or workshop, start with the building volume and required air changes to estimate total airflow. Then check the selected industrial air cooler's rated airflow and divide the total requirement among multiple units. Finally, adjust the equipment quantity and layout according to the actual heat sources, ventilation system, and working areas.
For a project quotation, the factory dimensions, ceiling height, local summer temperature and humidity, heat sources, and existing ventilation information should be provided so the industrial air cooler configuration can be evaluated more accurately.
