Demystifying Liquid Cooling: A Comprehensive Guide to Enhancing Data Center Efficiency

July 13, 2023

As data centers continue to evolve and handle increasingly demanding workloads, efficient cooling solutions have become a critical aspect of their design. One method that has gained significant attention and adoption is liquid cooling. 
By harnessing liquid's superior heat dissipation capabilities, data centers can achieve higher energy efficiency and improved performance when incorporating liquid cooling into their existing data center infrastructure.
 In this blog post, we will explore some of the major types of liquid cooling used in modern data centers, help you decide if liquid cooling will be a part of your future, and break down what could be the most optimal cooling solution going forward. 

The Major Types of Liquid Cooling

Liquid cooling is becoming increasingly popular in data centers as a more efficient method of dissipating heat generated by servers and other equipment. Here are some major types of liquid cooling that are commonly used in data centers:

Direct-to-Chip (D2C) Cooling

Direct-to-Chip cooling involves circulating coolant directly onto the surface of individual server chips or components. Bringing the cooling medium in close contact with the heat source ensures efficient heat extraction and prevents hotspots. Microchannels or heat spreaders are commonly used to distribute the liquid and enhance thermal conductivity, resulting in optimal cooling performance.
This type of liquid cooling can be 1-phase direct-to-chip cooling, also known as single-phase liquid cooling, which involves circulating a liquid coolant directly onto the surface of individual server chips or components. The coolant absorbs heat from the chips and carries it away, preventing thermal throttling and improving overall system performance. 

It can also be 2-phase that takes advantage of the heat-absorbing properties of a coolant that undergoes a phase change from liquid to vapor. This process occurs directly on the surface of the chips. As the coolant evaporates, it absorbs large amounts of heat, providing an exceptionally efficient cooling mechanism.

 Rear Door Heat Exchangers 

Rear Door Heat Exchangers are a localized cooling solution. Heat exchangers are attached to the rear doors of server racks, and a coolant flows through them to absorb heat from the exhaust air. The heated coolant is then cooled and recirculated. This method provides efficient cooling for individual racks, allowing for targeted heat dissipation.

 Chilled Water Cooling 

Chilled water cooling employs a system of circulating chilled water through pipes or coils within the data center. This chilled water absorbs heat from the air, effectively cooling the facility. It is a reliable and widely used liquid cooling solution, especially in larger data centers, and enables the use of economizers and cooling towers for efficient heat dissipation.

Is Liquid Cooling Right for My Data Center?

When considering whether liquid cooling is the right choice for your data center, there are three significant factors to evaluate:

First, assess the current and future cooling requirements of your data center. If you're experiencing high rack densities and struggling to meet the cooling demands with traditional air cooling, incorporating liquid cooling can offer an even more efficient solution, leading to improved performance and reduced risk of thermal issues.
Next, consider the available expertise and resources in your organization. Implementing liquid cooling systems could require specialized knowledge and skills during installation and ongoing maintenance. Consider whether your IT and data center teams have the necessary expertise or if additional training or external support would be required. Additionally, assess the compatibility of your existing infrastructure with liquid cooling solutions and consider the potential impact on your management framework.
Lastly, examine the scalability and future-proofing aspect. Liquid cooling offers excellent scalability for accommodating increasing computing demands. It allows for efficient cooling in high-density environments and can adapt to future hardware advancements.

By thoroughly evaluating these factors - cooling requirements, cost considerations, expertise availability, and scalability - you can decide whether liquid cooling is the right fit for your data center. It's advisable to consult with industry experts and vendors to gain a deeper understanding of the specific benefits and challenges associated with implementing liquid cooling in your unique environment. 

CPI’s Wide Range of Cooling solutions

CPI offers a variety of cooling solutions that are ideal for many data centers existing today and can be combined with liquid cooling solutions for fully integrated cooling infrastructure. Some of those options include:

Passive Cooling Solutions

Airflow Management Products: CPI offers various airflow management solutions, such as blanking panels, air dams, grommets, and cable management accessories, to optimize airflow and prevent hot air recirculation in cabinets and racks.

Active Cooling Solutions

Air Conditioning Units: CPI provided air conditioning units designed specifically for data centers, including rack-mounted air conditioners and ceiling-mounted air conditioners, to cool the environment effectively.

In-Row Cooling: CPI provided in-row cooling solutions, which include cooling units positioned between racks to provide localized cooling and enhance cooling efficiency.

Free Cooling: CPI offered solutions that leveraged outdoor ambient air to provide cooling while reducing energy consumption and operating costs. 

Is Hybrid Best?

As data processing demands continue to rise, a hybrid approach that combines direct-to-chip liquid cooling with traditional air-cooling methods has emerged as a promising solution. Integrating these two cooling techniques allows for great energy efficiency while keeping the existing data center footprint.  
Enhanced Cooling Efficiency
Direct-to-chip liquid cooling is renowned for its exceptional heat dissipation capabilities. By efficiently removing heat directly from the source, such as CPUs or GPUs, liquid cooling offers superior thermal conductivity compared to air. Combining liquid cooling with traditional air cooling optimizes cooling performance, ensuring lower operating temperatures within the data center. This enhanced cooling efficiency translates into improved system stability and longevity. 

Increased Density and Server Consolidation

The ability to accommodate higher server densities is a pressing need for data center operators. Liquid cooling provides a practical solution by handling more heat compared to air cooling alone. By leveraging direct-to-chip liquid cooling, data centers can consolidate more servers within the same physical space. This not only maximizes resource utilization but also boosts computing capacity, enabling organizations to scale their operations effectively.

Energy Efficiency

Energy consumption is a significant concern for data centers. Direct-to-chip liquid cooling reduces reliance on energy-intensive air conditioning methods. By dissipating heat at the chip level, liquid cooling minimizes the overall power required for cooling. The integration of liquid cooling with traditional air cooling translates into substantial energy savings and reduced operational costs for data center operators. This energy-efficient approach aligns with sustainability initiatives and helps mitigate the environmental impact of data center operations.

  Improved Reliability

Overheating poses a significant risk to the reliability of data center infrastructure. Excessive heat can lead to component failures, resulting in costly downtime and repairs. Direct-to-chip liquid cooling offers a reliable solution by maintaining stable operating temperatures. By combining liquid cooling with air cooling, data centers create a robust cooling infrastructure that minimizes the risk of overheating and extends the lifespan of critical components. Enhanced reliability translates into improved uptime and a better user experience for customers.

 Flexibility and Scalability

Data centers need flexible and scalable cooling solutions to adapt to evolving requirements. The combination of liquid and air cooling precisely offers that. Liquid cooling can be strategically deployed in high-density areas, where heat dissipation is most critical. Meanwhile, traditional air cooling can efficiently handle lower heat loads. This hybrid approach allows data center operators to optimize cooling resources, accommodate changing workload demands, and ensure efficient resource allocation.
Combining direct-to-chip liquid cooling with traditional air cooling offers data centers a compelling solution. It provides enhanced cooling efficiency energy savings, and reduced noise. 
It does all this while maintaining optimal performance, cost reduction, and sustainability alignment. As high-performance computing demand rises, integrating liquid cooling into existing air-cooled infrastructure paves the way for future data centers.
Posted by Angelique Pollock, Digital Content Specialist at 7/13/2023 1:18:02 PM
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