Dry Cooler Auxiliary Cooling Air Conditioning System Computer Room Natural Cooling

Data Center Air Conditioning System: Provides a precise, constant temperature and humidity environment for data centers, ensuring stable operation of IT equipment. Its key feature is year-round operation and high cooling demand.

Natural Cooling: Utilizes naturally occurring low-temperature outdoor air or chilled water to cool the data center, thereby reducing or completely eliminating the use of energy-intensive compressors. This is the core of energy conservation.

Dry Cooler: A heat exchanger whose internal fluid (usually water or ethylene glycol solution) indirectly exchanges heat with the outside air. Only sensible heat is exchanged throughout the process; there is no latent heat exchange (i.e., no condensation or dehydration process), hence the name "dry" cooling. It is essentially an "air-liquid" heat exchanger.

Dry cooler-assisted cooling air conditioning systems are essentially indirect, liquid-mediated natural cooling solutions.

This system is often combined with a traditional chilled water system to form a composite cooling system. Its core components include: indoor precision air conditioning units (with water-cooled heat exchange coils), dry coolers, circulating water pumps, plate heat exchangers, and necessary valves and control units.

The system automatically switches between three modes based on changes in outdoor temperature to achieve maximum energy savings:

1. Complete Natural Cooling Mode (Winter/Spring/Autumn)

Trigger Condition: When the outdoor temperature is sufficiently low (e.g., below a set value, such as 5°C).

Workflow

The compressor refrigeration unit is shut down.

Ethylene glycol solution (antifreeze) is circulated between the dry cooler and the plate heat exchanger via a pump.

Outdoor cold air flows through the finned tubes of the dry cooler, cooling the ethylene glycol solution inside.

The cooled ethylene glycol solution flows into the plate heat exchanger, where it exchanges heat with the chilled water in the machine room on the other side, cooling the chilled water.

The cooled chilled water is then sent to the precision air conditioning terminals in the machine room to absorb heat from the machine room.

Energy Saving Effect: Excellent. In this mode, the compressor completely stops working, consuming only the energy of the dry cooler fan and circulating water pump. The PUE (Power Usage Effectiveness) can be very close to 1.1 or even lower.

2. Hybrid Cooling Mode (Transitional Seasons)

Trigger Condition: When the outdoor temperature is insufficient to meet all cooling needs solely through the dry cooler (e.g., between 5°C and 15°C).

Workflow: The dry cooler first pre-cools the ethylene glycol solution.

The pre-cooled ethylene glycol solution then partially cools the chilled water through a plate heat exchanger.

If the chilled water temperature still does not meet the requirements, the refrigeration unit will start to provide supplemental cooling, lowering the water temperature to the set point.

Energy Saving Effect: Significant. The compressor only needs to bear a portion of the load, greatly reducing its working time and intensity, resulting in overall energy consumption far lower than the traditional mode.

3. Mechanical Cooling Mode (Summer)

Trigger Condition: When the outdoor temperature is very high, and the dry cooler cannot provide effective cooling (e.g., above 15°C).

Workflow: The system switches to the traditional mechanical cooling mode.

The dry cooler stops working or is used only as a condenser (in some designs).

The refrigeration unit runs at full capacity, bearing the entire cooling load.

Energy Saving Effect: None. This mode is no different from a conventional air conditioning system, with the highest energy consumption. 

Key Advantages

Extremely High Energy Efficiency and Low PUE: Maximizing the use of free outdoor cooling sources significantly reduces compressor energy consumption, its core advantage.

High Reliability: The dry cooler itself is a purely mechanical component with no complex compression cycle, resulting in a simple structure and high reliability. In natural cooling mode, it reduces the host unit's operating time and extends its lifespan.

Protecting the Computer Room Environment: As an indirect natural cooling system, the air inside the computer room is completely isolated from the outdoor air. This ensures that the cleanliness and humidity of the computer room are unaffected by external factors, preventing dust, salt, pollutants, and humid air from directly entering the computer room, providing perfect protection for the equipment.

Water Conservation: Compared to cooling tower systems, dry coolers do not require water evaporation, offering a significant advantage in areas with limited water resources.

Flexible Installation: Dry coolers can be installed on rooftops or outdoor platforms, saving indoor space.