Innovative Cold Plate Cooling Technologies Two-phase & Air-liquid Hybrid Solutions for Modern Data Centers
Two-phase cold plate cooling represents an advanced form of cold plate liquid cooling. Using fluorinated compounds as refrigerants can significantly boost the reliability of liquid cooling systems. Once leaked, these fluids turn into non-conductive gas and will not damage servers. Most fluorinated refrigerants have low boiling points; they vaporize after absorbing heat inside cold plates, greatly enhancing heat dissipation efficiency, making this technology ideal for high density server cooling and high-demand AI data center cooling scenarios. According to NVIDIA’s technical documents, applicable refrigerants include R134a, R513A, R515B, R471A, 1233zd, R1234yf and 3M Novec HFE-7000 series. When R134a is adopted for two-phase cold plate cooling, it handles 2.5kW heat load per GPU and 175kW per rack, with a maximum heat dissipation capacity of 8 W/(cm²·℃).
This two-phase technology has two mainstream derivatives. The gravity heat pipe solution supports an ultra-high power density of 100kW per rack and achieves a PUE as low as 1.07. It requires no circulating pumps and relies solely on temperature difference to drive refrigerant flow. With no moving parts and maintenance-free fluorinated fluid, it features superior reliability and is highly suitable for edge computing. The pumped heat pipe solution has been developed by NVIDIA and domestic manufacturers. It enables flexible layout between heat sinks and racks, and can even build multi-rack combined systems. Currently, such products are still in the research phase with low commercial maturity.
Air-liquid hybrid cold plate cooling has attracted wide attention and become a promising trend. This data center liquid cooling solution is developed to solve three typical industry pain points. It helps reuse original air cooling equipment during legacy data center renovation. For new builds with limited pipeline and underfloor space, it avoids layout difficulties caused by dual liquid cooling pipelines. It also integrates outdoor units for air and liquid cooling to save installation space and adapt to variable air-liquid mixing ratios.
Air-cooled CDU is the core solution for legacy facility upgrades. It replaces traditional water-to-water plate heat exchangers with air-to-water types like finned tube and microchannel heat exchangers. CoolIT launches AHx series CDU with cooling capacity from 2kW to 100kW, while TOP-C provides 110kW rack-mounted CDU. Inspur also offers three types: integrated, rack-mounted and rear-door style. The rack-mounted design fits well with rack level liquid cooling, while integrated and rear-door products match the layout of row level liquid cooling. All models transfer server heat to ambient air via heat exchangers and fans, with full monitoring of refrigerant temperature and pressure.
The air-liquid combined terminal is designed for sites with tight pipeline space, and has been standardized by OCP as part of a complete data center liquid cooling system. In this design, 27℃ chilled water first passes through rear door cooling units for air cooling. The water heated to 34℃ then flows into the CDU for primary liquid cooling, and the 44℃ water returns to the central cold source for re-cooling. This tandem structure maximizes space utilization while maintaining stable heat dissipation.
For scenarios with limited outdoor unit space, the air-liquid shared cold source is a practical choice. Nortek’s SPLC chiller adopts microporous hydrophobic membrane evaporation technology, which isolates circulating water from outdoor air and delivers chilled water close to the ambient dew point, with the outlet water temperature always kept above the local dew point. This technology enriches the full range of liquid cooling for data center, providing flexible, space-saving and high-efficiency cooling options for both newly-built and renovated data centers.
As a globally respected frontrunner in liquid cooling, EXTRCOOL delivers purpose-built solutions tailored to high-density AI and HPC data centers. Our premium thermal hardware portfolio features dual-mode CDUs, manifolds, cold plates, rear-door heat exchangers, dry coolers, and containerized cooling units. Engineered for reliability, interoperability, and scalability, these systems enable a seamless one-stop full liquid cooling deployment. We support data center operators and enterprises across South Asia, Central Europe, West Africa, East Asia, and South America.
