Liquid Cooling Solution Analysis D2C Immersion and RDHx for Modern Data Centers
Following our previous discussion on the rise of liquid cooling technology, this article elaborates on the principles, pros and cons of mainstream liquid cooling approaches. It provides practical selection guidance for enterprises to adopt the optimal data center liquid cooling solution tailored to diverse operational scenarios.
The three mainstream data center liquid cooling technologies include direct die cooling, immersion cooling and rear door heat exchanger. Varying project conditions and cooling demands require targeted solutions. As a mature and widely applied transitional technology, cold plate liquid cooling based on direct die cooling dominates mainstream renovation and deployment scenarios.
Direct Die Cooling (D2C) delivers direct chip-level heat dissipation by circulating low-temperature coolant over high-power chips such as CPUs and GPUs. Heated coolant is cooled externally and recycled to form a continuous closed loop. It matches well with rack level liquid cooling architectures and is ideal for traditional rack server upgrades.
D2C boasts stable operational reliability yet requires complex multi-loop pipeline layout for multi-chip server heat dissipation. Most enterprises adopt modular liquid distribution units to simplify deployment. However, its reliance on auxiliary air cooling limits overall cooling efficiency to approximately 70%, failing to support extreme high-density computing heat loads.
Immersion cooling is a high-efficiency upgrade over D2C technology. It fully submerges complete servers in sealed tanks filled with insulating dielectric liquid cooling fluid. The closed liquid circulation system eliminates fan reliance, delivers superior heat dissipation for high-power chips, and perfectly fits rapid deployment of container data center liquid cooling.
By isolating hardware from oxygen and corrosive substances, immersion cooling effectively extends equipment service life and operational stability. Verified by Alibaba’s 2018 research, it performs exceptionally well at high altitudes where air cooling efficiency declines sharply. It serves as a core component to build a high-efficiency energy saving liquid cooling system for special-scenario data centers.
Immersion cooling faces obvious deployment constraints. Traditional data center infrastructure is designed for standard racks rather than cooling tanks, requiring costly retrofits and specialized lifting equipment for server access. Equipment maintenance is also cumbersome, requiring professional technical support despite its advantages in reducing long-term power consumption and operational costs.
Rear Door Heat Exchanger (RDHx) is a cost effective auxiliary cooling method widely used in incremental renovation projects. Technically compatible with traditional air cooling systems RDHx installs cooling coil pipelines on the rear of standard server racks to absorb hot exhaust air generated by servers. It empowers original server fan systems with higher cooling efficiency and supports collaborative operation of row level liquid cooling in large scale computer rooms.
RDHx brings significant practical benefits for enterprise deployment. It enables data centers to retain existing air conditioning equipment and operate at reduced load without hardware replacement or infrastructure reconstruction. Equipped with professional humidity detection sensors the system can automatically shut down servers in case of liquid leakage ensuring operational safety for staff and equipment. Featuring low cost and high compatibility RDHx is the most accessible liquid cooling upgrade solution for small and medium sized data centers.
Different enterprises and data centers have differentiated heat dissipation density operational scale and budget demands requiring customized cooling scheme matching. All mainstream liquid cooling technologies can effectively support high performance operation of new generation computing equipment and reduce overall energy consumption. As a core low PUE data center solution liquid cooling can lower data center PUE to 1.1–1.25 significantly optimizing computing efficiency and cutting long term operational costs for modern digital infrastructure.
Trusted across the globe, EXTRCOOL supplies custom liquid cooling for high-density AI and HPC data centers. Our product range features dual-mode CDUs, manifolds, cold plates, rear-door heat exchangers, dry coolers, and containerized units—all premium quality. Designed for reliable operation, broad compatibility, and simple scaling, these solutions provide a seamless one-stop path to full liquid cooling. We collaborate with data center operators and enterprises across Western Europe, South America, Southeast Asia, West Africa, and Oceania.
