Why Data Centers Adopt Cold Plates for Liquid Cooling Over Immersion
2023725 Yulin Wang
The increasing power density of data center racks, driven by technologies like cloud computing, generative AI, and crypto mining, has led to the exploration of liquid cooling as a thermal management solution. Even with containment, traditional air-cooling methods struggle to meet the cooling demands of densely packed servers. Due to the increased utilization of high-density racks, IDTechEx's latest research report predicts a 16% CAGR in cold plate cooling until 2023, along with strong growth for other liquid cooling alternatives.
There are three main approaches for integrating liquid cooling into data centers:
Designing data centers exclusively for liquid cooling: This involves creating smaller and more efficient data centers with high compute capabilities using immersion cooling. However, due to the high costs involved, IDTechEx believes that immersion cooling will grow but, in the short term, will likely be implemented on a smaller scale, such as pilot projects by large companies.
Designing data centers with both air cooling and liquid cooling infrastructure: This allows for a future transition to liquid cooling while initially utilizing air cooling. However, designing data centers with redundant features (e.g., liquid cooling manifolds, pipes, etc.) from scratch may not always be a preferred option for end-users with limited budgets.
Integrating liquid cooling into existing air-cooled facilities: This is the most common approach and is expected to be the preferred solution in the short- to mid-term future. It involves transitioning some of the capacity of air systems to liquid cooling systems. There are several reasons for its popularity:
- Cost efficiency: Utilizing existing infrastructure reduces complexities and upfront costs compared to the other two options.
- Limited demand for full liquid cooling integration: Despite increasing data center densities, IDTechEx believes that the transition to full liquid cooling will occur gradually, starting with a small number of racks in the data center and then gradually expanding to all racks.
- Performance evaluation: Direct-to-chip cooling is still in its early stages compared to air cooling. Therefore, many data center server suppliers and end-users prefer to evaluate its performance on a smaller scale before mass deployment.
Driven by the demand of retrofitting existing air-cooled data centers, cold plate cooling, also known as direct-to-chip cooling, is the dominant liquid cooling solution in the data center industry. Traditionally, cold plates are mounted directly on top of heat sources (e.g., chipsets, CPUs, etc.) with a layer of thermal interface material (TIM) in between to enhance heat transfer. Inside the cold plate, the liquid flows through the microstructure and out to some form of heat exchanger. The diagram below outlines typical cold plate designs for data center applications. Thermal interface materials can be found in various data center components, including chipsets, processors, and power supplies. IDTechEx believes that the increasing adoption of cold plates will also drive the market demand increase of TIMs in data centers, particularly those used for processors and chipsets. IDTechEx's "Thermal Interface Materials: Technologies, Markets, and Forecasts 2023-2033" report provides an overview of TIMs for various emerging industries such as data centers, electric vehicle batteries, 5G, advanced driver-assistance systems (ADAS), and consumer electronics.
Traditional, and Intel's new cold plate structure eliminating TIM. Source: IDTechEx
Intel's innovative approach in their new design involves integrating cold plates directly into the package, eliminating the use of TIM2 (Thermal Interface Material 2), and reducing the bulk thermal resistance or impedance. This integration offers advantages in terms of thermal management. However, it also introduces greater design complexity due to the micro-level embedding of the cold plate within the package.
Cold plate cooling for data centers provides a flexible and deployable solution for liquid cooling. The unique differentiating factor lies in the internal microstructure of the cold plates. Unlike immersion cooling, cold plate cooling allows data center integrators and server suppliers to partially incorporate liquid cooling into their facilities at a relatively low upfront cost, with the ability to transition to a fully liquid-cooled data center gradually over time. IDTechEx predicts a soft start of cold plate adoption, followed by a rapid increase as more end-users adopt the technology. The yearly revenue for cold plate cooling is projected to grow at a compound annual growth rate (CAGR) of 16% over the next 10 years, and the fast increase of cold plate hardware also drives the increase in the markets for components such as pumps and coolant distribution units (CDUs). IDTechEx's latest report, "Thermal Management for Data Centers 2023-2033", provides a comprehensive overview of the data center cooling industry, considering the technology used, market players, and opportunities for components and materials.