On December 22, 2025, a significant advancement in technology was announced: Mitsubishi Heavy Industries, Ltd. (MHI) and EXEO Group, Inc. have successfully developed and commenced the commercial utilization of Japan's first-ever graphics processing unit (GPU) servers that utilize a two-phase direct-to-chip cooling system (two-phase DLC). This innovative setup is implemented within EXEO Group's data center. As generative AI continues to gain traction, the demand for GPU servers has surged, but managing the substantial heat they produce poses considerable challenges. Thankfully, the introduction of the two-phase DLC offers a safe and effective solution to this pressing issue.
Traditionally, GPUs have relied on air cooling systems, which use heat sinks to dissipate heat. However, modern GPUs can generate between 1,000 to 1,400 watts of heat, making it increasingly difficult to maintain stable operating temperatures. Let's explore the main challenges associated with this conventional cooling method:
Firstly, the inefficiency of air cooling systems raises concerns regarding the GPUs' stability. Inadequate cooling can lead to performance limitations and even potential failures. The two-phase DLC system addresses this by employing a cold plate that directly interfaces with the GPU chip. Through the circulation of both liquid and gaseous coolant, this system achieves a heat transfer rate significantly superior to that of traditional air cooling methods. As a result, it ensures reliable operation for high-output GPUs while simultaneously reducing the risk of failure across the entire system.
Another critical issue with conventional cooling solutions is the vulnerability of single-phase liquid cooling systems to coolant leaks, which can damage servers. The two-phase DLC system enhances safety by utilizing non-conductive refrigerants. This means that in the unlikely event of a leak, the refrigerant will not short circuit any electrical components, thereby protecting expensive IT infrastructure from costly damage. Users can operate this system with confidence knowing that their equipment is secure.
Additionally, air cooling systems often require large fans and auxiliary cooling equipment, leading to increased power consumption and higher CO2 emissions. However, the highly efficient heat removal process facilitated by the two-phase DLC significantly reduces the energy required for these cooling fans. This not only improves the cooling power factor but also lowers the Power Usage Effectiveness (PUE), a metric used to gauge the efficiency of data center energy usage. Consequently, this innovation helps to decrease overall energy consumption, minimize environmental impacts, and reduce operational costs, all while lowering the carbon footprint associated with data center operations.
To enhance the cooling efficiency and ensure the reliable functioning of high-performance GPU servers—especially those tasked with generative AI functions—EXEO Group has adopted MHI’s pioneering two-phase DLC technology. This marks the first instance of such a system being used commercially in Japan. The collaboration between MHI's advanced heating and cooling technologies and EXEO Group's vast experience in constructing and running data centers has culminated in a comprehensive service offering for GPU servers.
Looking ahead, both companies are committed to advancing their technological capabilities in system development and operational processes. They aim to meet the escalating demands of large-scale data centers and leverage their combined expertise to provide dependable, environmentally friendly solutions for data center facilities, thus fostering green transformation (GX) within the IT industry.
Key Terms:
1. Two-phase DLC (Direct Liquid Cooling): This technology circulates both liquid and gas as coolants directly on the GPU chip to efficiently manage heat.
2. Heat Sink: A device designed to dissipate heat generated by electronic components, preventing overheating.
3. Power Usage Effectiveness (PUE): An efficiency metric for data centers; a PUE closer to 1.0 indicates better energy efficiency.
4. Carbon Footprint: A measure of the total greenhouse gases emitted by individuals, companies, or products, whether directly or indirectly.
