How Do V-type Dry Coolers Support Free Cooling?

V-type dry coolers support free cooling by rejecting heat directly to ambient air whenever outdoor conditions are favorable, allowing data centers to reduce or completely shut down mechanical chillers. The mechanism works as follows:

How V-Type Dry Coolers Enable Free Cooling

1. Direct Heat Rejection to Ambient Air

When the outdoor air temperature is lower than the return fluid temperature from the data center, the V-type dry cooler transfers heat through its finned coils directly to the air—no compressor operation is required.

• Heat source: warm return water / glycol

• Heat sink: ambient air

• Energy input: fans only

2. High Air-Side Heat Transfer Efficiency

The V-shaped coil arrangement provides:

• Large effective heat transfer surface

• Uniform airflow across both coil faces

• High heat rejection density in a compact footprint

This maximizes sensible heat transfer, even at small temperature differences (low approach temperatures), which is critical for free cooling operation.

3. EC Fan Modulation for Partial and Full Free Cooling

V-type dry coolers typically use EC axial fans with variable speed control:

• Fans ramp up during warm ambient conditions

• Fans slow down or cycle off in cold conditions

• Fine control maintains supply water temperature without chillers

This enables smooth transitions between partial free cooling and 100% free cooling.

4. Integration with Free Cooling Architectures

V-type dry coolers are commonly used in:

• Direct free cooling systems (dry cooler only)

• Hybrid systems (dry cooler + chiller)

• Series or parallel arrangements with plate heat exchangers

Control logic automatically prioritizes dry cooler operation whenever ambient conditions allow.

5. Extended Free Cooling Hours

Compared with flat-bed designs, V-type dry coolers offer:

• Higher heat rejection per square meter

• Better airflow management

• Improved performance at low ΔT

This increases the number of hours per year during which free cooling is available, especially in temperate and cold climates.

6. No Water Consumption

Unlike cooling towers or adiabatic systems, dry coolers:

• Do not evaporate water

• Avoid water treatment and legionella risks

• Are ideal for regions with water scarcity or strict regulations

7. Impact on Data Center Efficiency

By maximizing free cooling:

• Chiller runtime is significantly reduced

• Electrical energy consumption drops

• PUE improves (often by 10–30%, climate-dependent)

• System reliability increases due to fewer mechanical components in operation

Summary

V-type dry coolers enable free cooling by combining high-efficiency air-side heat exchange, variable-speed fan control, and compact, high-density coil geometry, allowing data centers to reject heat to ambient air for a large portion of the year without mechanical refrigeration.