Data centers house high-performance computing equipment that generates substantial heat.

Cooling in data centers removes heat from servers and other hardware to keep them running efficiently. This is achieved by circulating cool air or liquid around the equipment while redirecting hot air or heated liquid away. Without cooling, excessive heat buildup can cause system failures, slow performance, and shorten the lifespan of critical components.

Their servers generate more heat as data centers process more data and run more applications. To prevent overheating and keep systems running smoothly, they need efficient cooling methods to remove excess heat and maintain safe temperatures.

The type of cooling system directly influences the selection of power and data cables. The right cables must be chosen based on temperature resistance, moisture exposure, EMI shielding, and flexibility for installation. In this article, we explain the different types of cooling systems in data centers and the cables accompanying these cooling systems.

Data Center Cooling Systems

Cooling methods can be broadly categorized into air-based, liquid-based, and hybrid cooling solutions. Each has different implications for cable selection, cost, efficiency, and best-use cases. Below, we explain them all.

Air-based Cooling Systems

Air-based systems rely on airflow management to dissipate heat.

There are different types of air-based cooling in data centers:

CRAC (Computer Room Air Conditioning) & CRAH (Computer Room Air Handler) Units

CRAC units use refrigerants and compressors, while CRAH utilizes chilled water and fans.

• Best for: Traditional enterprise data centers and colocation facilities.

• Cost: Moderate to high, depending on infrastructure.

• Efficiency: Lower than liquid cooling because air has lower heat capacity than liquid, but widely used.

• Drawbacks: Energy-intensive, less effective for high-density workloads as this type of air cooling would struggle to remove heat in high-density environments.

Hot Aisle/Cold Aisle Containment

This type of air-based system separates hot and cold airflows to improve efficiency compared to simpler air-based systems.

• Best for: Large-scale enterprise data centers, and cloud computing data centers.

• Cost: Moderate initial investment, but energy savings over time.

• Efficiency: Improves air-cooled setups but still requires additional cooling.

• Drawbacks: Requires precise airflow management: supplemental cooling sources to generate cool air.

In-Row and In-Rack Cooling

This type of air-based system places cooling units between or within server racks.

• Best for: High-density data centers hyperscale environments.

• Cost: Higher upfront costs, and lower operational expenses.

• Efficiency: Highly effective for targeted cooling.

• Drawbacks: Requires careful planning and integration. For best effectiveness, you should place these based on the heat load.

Liquid-Based Cooling Systems

Liquid cooling systems offer higher efficiency and are ideal for high-density environments. This is because liquids absorb and transfer heat faster than air, allowing for better thermal management and lower energy consumption.

Chilled Water Systems

This type of liquid-based cooling system uses a central chiller to supply cold water to CRAH units.

• Best for: Large enterprise data centers and colocation facilities.

• Cost: High due to infrastructure requirements.

• Efficiency: More energy-efficient than air cooling.

• Drawbacks: Requires dedicated plumbing and cooling towers.

Direct-to-Chip Liquid Cooling

This liquid cooling circulates liquid directly to heat-generating components.

• Best for: High-performance computing (HPC) centers, and AI-driven data centers.

• Cost: High but offset by improved performance.

• Efficiency: Very high, ideal for compact, high-power workloads.

• Drawbacks: Requires custom hardware and integration.

Immersion Cooling

This liquid cooling submerges servers in a dielectric coolant that absorbs heat.

• Best for: Hyperscale data centers, blockchain mining, and high-density AI computing.

• Cost: High initial investment, but long-term savings.

• Efficiency: One of the most efficient cooling methods available.

• Drawbacks: Requires specialized equipment and redesigning server layouts.

Hybrid Cooling Solutions

These solutions combine air and liquid cooling for optimized efficiency. By combining these elements, it remains equally useful for both high-density and low-density environments.

Evaporative Cooling

This typ of solution uses water evaporation to lower temperatures. This reduces the reliance on mechanical refrigeration.

• Best for large cloud data centers and cost-sensitive operations.

• Cost: Moderate, with potential savings in energy use.

• Efficiency: Higher than traditional air cooling.

• Drawbacks: It depends on climate conditions as it relies on water evaporation to cool the air.

Adiabatic Cooling

It enhances evaporative cooling with controlled water usage.

• Best for: Sustainable data centers, areas with water constraints.

• Cost: Moderate, but reduces water consumption.

• Efficiency: More efficient than basic evaporative cooling.

• Drawbacks: Requires monitoring of humidity levels.

Geothermal Cooling

• Leverages underground water sources for heat exchange.

• Best for green data centers and regions with geothermal resources.

• Cost: High installation cost but low operational expenses.

• Efficiency: Extremely efficient for long-term use.

• Drawbacks: Limited by location. Underground water that can be drilled should be available.

Choosing the Right Cables for Data Center Cooling Systems

The type of cooling system impacts the selection of power and data transmission cables. Cables must be chosen based on many factors: temperature tolerance, moisture resistance, electromagnetic interference (EMI) protection, and routing flexibility to ensure data center reliability and efficiency. Here is our guide on how to properly choose them:

Power Cables

• THHN – Standard, heat-resistant, cost-effective, used in air-cooled systems. Not ideal for humid environments due to its nylon coating absorbing moisture.

• XHHW-2 – Water-resistant, low dielectric loss, suited for liquid-cooled environments. Less flexible compared to THHN, making routing in tight spaces harder. However, it is often chosen based mostly on its water-resistance properties.

• MC (Metal Clad) Cable – Shielded, durable, reduces EMI in hybrid cooling setups. Heavier than standard power cables, requiring strong support structures. In general, it is excellent for high-EMI areas in hybrid cooling systems.

• Tray Cable (TC-ER, TC-ER-JP) – Flexible, flame-retardant, supports overhead routing in humid conditions. Not suited for direct burial or submerged applications. It is used in different overhead setups regardless of the cooling type.

• SOOW/SEOOW – Flexible, impact-resistant, and great for in-row and in-rack cooling. Note that it is bulkier and more expensive than THHN or tray cables.

Data Cables

• Cat 6A (STP) – Shielded, supports 10Gbps, ideal for air-cooled high-EMI areas. 

• Cat 7 / Cat 8 – Extra shielding, handles up to 40Gbps, best for liquid-cooled high-density racks. Can be stiff and difficult to route, overkill for lower-speed applications.

• Fiber Optic Cables – Immune to EMI, ideal for all cooling systems, best for immersion cooling.

Special Considerations for Immersion Cooling

Immersion cooling requires cables that withstand continuous submersion in a dielectric coolant. Here is what immersion cooling generally requires:

• Cables must resist the absorption of dielectric fluids.

• Fiber optics are ideal as they are non-conductive and immune to EMI.

• Power Cable Insulation Types:

• Teflon (PTFE), XLPE, FEP, EPR, Silicone Rubber – Various levels of moisture and heat resistance.

• Liquid-tight connectors can prevent fluid ingress, ensuring long-term performance.

• Thermoset jacketing provides added durability in submerged environments.

Conclusion

Choosing the right cooling system ensures stable performance and energy efficiency in a data center. Cables must be selected based on cooling conditions to support reliable power distribution and data transmission. In high-density or liquid-cooled setups, heat-resistant and moisture-proof cables prevent failures and ensure long-term durability. In low-density or air-cooled areas, flexible and lightweight cables like THHN or tray cables are the best bet.

At Nassau National Cable, we offer the best power cables that suit cooling setups in your data centers.