Recommended Dehumidifiers for Subway Stations

Subway stations are enclosed, densely populated, and have multiple sources of humidity. Dehumidification and ventilation schemes must be designed in conjunction with fresh air intake, temperature and humidity control, and equipment durability.

There are four parts of the solution: humidity source → system solution → equipment configuration → management and maintenance.

1. Analysis of humidity sources

The humidity in subway stations mainly comes from:

External humid air infiltration: The station hall, entrances, and exits are connected to the ground, allowing humid and hot air to continuously enter in the summer.

Groundwater infiltration: soil moisture, groundwater leakage.

Personnel respiration and surface evaporation: With a large number of passengers, humidity accumulates quickly.

Air conditioning condensate: When the condensate is not discharged smoothly, it will evaporate back into the air.

2. Core ideas of the plan

The dehumidification scheme of subway stations should be combined with the ventilation system, as a standalone dehumidifier cannot meet the air quality requirements of large spaces.

The overall idea is "mechanical ventilation+precise dehumidification+zone control".

(1) Mechanical ventilation system

Fresh Air Unit (MAU): Introduce outdoor air and perform pre-treatment (filtration, dehumidification, cooling, or heating).

Exhaust system: wet air is discharged through the station hall, platform ceiling, and equipment well.

Air volume control: dynamically adjust the fresh air volume according to passenger density (can be linked with CO₂/humidity sensors).

(2) Central air conditioning dehumidification function

Cooling and dehumidification: Use a chiller or direct expansion unit to cool the air below the dew point for dehumidification, and then reheat it to a comfortable temperature (to prevent overcooling).

Reheating device: Waste heat recovery coils or electric heaters can be used to warm the dehumidified cold air to 24-26 ℃, thereby avoiding the sensation of dampness and coldness.

(3) Localized enhanced dehumidification

Install commercial-use ceiling dehumidifiers or floor-standing dehumidifiers in equipment rooms, channel ends, and platform corners that are prone to moisture accumulation to quickly reduce humidity. The Preair CFZ40 large industrial dehumidifier has a cart design and a rigid shell. If you need large-sized dehumidifiers, please get in touch with us.

For ventilation blind spots (such as storage rooms and control rooms), small duct dehumidifiers can be connected to the existing air duct system.

(4) Groundwater control

Waterproof coating, epoxy sealing, drainage ditch+water collection pump, and other methods should be prioritized at the leakage site to reduce the dehumidification burden.

3. Recommended device configuration

4. Control and Management

Humidity setting: Generally maintained at 50-60% RH, and can be as low as 45% RH between devices to prevent electrical moisture.

Automatic linkage: The humidity sensor is linked with the fresh air unit, air conditioning unit, and dehumidifier to reduce energy consumption.

Inspection system: Regularly clean the filter screen, inspect the condensate drainage pipe, and test the accuracy of the humidity sensor.

Energy consumption optimization: Reduce the operation of dehumidifiers during low humidity periods (such as the dry season in winter) and only retain necessary ventilation.

5. Advantages of the plan

Continuity: Combining ventilation and dehumidification to ensure all-weather humidity control.

Comfort: After dehumidification, the air temperature can be controlled, and passengers will not feel chilly.

Mold and rust prevention: It has a significant effect on extending the service life of equipment and track equipment.