Direct Liquid Cooling for Data Centers: How It Works & Key Benefits

Servers have become essential in our life, particularly since institutions, companies and consumers use the Cloud daily. The number of data centers keeps increasing. Servers also become more and more powerful and therefore, generate more and more heat. While still widely used in data centers, the potential of traditional air-cooling systems is limited, more so when taking the impact on the environment into account. Several liquid-based cooling technologies have emerged, among them is direct liquid cooling (DLC), also called direct to chip liquid cooling.

Contrary to immersion cooling, direct liquid cooling doesn’t involve submerging an entire server in coolant.

Direct-to-chip cooling is a server cooling technique that circulates liquid coolant (typically water or a water-glycol mixture) through cold plates mounted directly onto the most heat-generating components: CPUs, GPUs, and memory modules. Heat is absorbed at the chip level and transferred to the coolant, which is then routed to a heat exchanger or cooling distribution unit before being recirculated.

This direct thermal contact with the chip makes DLC significantly more efficient than air cooling, which relies on fans to move ambient air across components, and more accessible than immersion cooling, which requires specifics tanks and fully submerged server designs. DLC systems capture 70 to 80% of server heat at the chip level, with a small supplementary air cooling system handling the remaining 20 to 30% from memory, storage, and network components.

Two variants of DLC exist:

• Single-loop DLC: a single coolant circuit runs from the cold plate directly to the facility's cooling infrastructure,
• Dual-loop DLC: a primary coolant loop handles chip-level heat, while a secondary loop connects to the facility's water circuit, keeping the two loops thermally isolated for added safety and flexibility.

Direct Liquid Cooling consistently achieves PUE between 1.05 and 1.10 compared to 1.4 to 1.8 for typical air-cooled facilities (Uptime Institute, 2024). Real-world deployments confirm the impact: at the GWDG research facility in Germany, DLC deployment raised rack power density from 23.5 kW to 96 kW and improved PUE from 1.24 to 1.07 (CoolIT Systems, 2024).

The liquid cooling market is projected to grow from $5.52 billion in 2025 to $15.75 billion by 2030, at a CAGR of 23.31%, with direct-to-chip DLC already commanding a 47% market share and deployed in 22% of data centers worldwide (Introl, 2025).

Energy efficiency and sustainability

It’s no surprise that the environmental factor plays a big role when choosing a cooling solution. Air cooling has been proved to be the most impactful on the planet due to its numerous fans needing electricity to function. Therefore, energy costs are high, higher than using a liquid cooling solution such as direct on chip cooling.

When comparing air and liquid cooling, the Power Usage Effectiveness (PUE) is essential. It assesses how efficient data centers or tech infrastructures are in using power. To calculate it, divide the total of facility power by IT equipment power. For instance, a datacenter with a 1.25 PUE uses 50 000kWh in total and 40 000kWh is used for IT equipment only. The higher the PUE, the less efficient the data center is, consequently impacting energy costs.

A PUE of 1.2 is now considered excellent for air-cooled data centers. But with the EU Energy Efficiency Directive mandating a PUE below 1.3 by 2030 for new facilities, and Singapore already requiring below 1.2, the pressure to adopt advanced cooling technologies has never been greater. 

According to the Uptime Institute's 2024 Global Data Center Survey, data center owners and operators reported an average annual PUE of 1.54 at their largest facilities, showing that despite years of optimization efforts, the industry average has barely moved. The primary reason: the vast majority of data centers still rely on traditional air cooling.

DLC can also be used to re-use the waste heat by redirecting the heated liquid in a heating system of a building or any other infrastructures.

Flexibility and easy retrofit

Most data centers still possess an air-cooling system. Switching to a new cooling solution such as direct liquid cooling can seem complicated. However, the existing data center infrastructure can be reused with minor reconstruction and modification. This process is called retrofitting. When a facility goes through this process, cost-effective options are provided to increase efficiency and/or capacity without changing the building infrastructure.

Reducing noise pollution

Direct liquid cooling needs less fans, greatly reducing the noise pollution and creating a better work environment for the maintenance technicians who can stay longer inside the facility and concentrate fully.

Air-cooled data centers generate between 85 and 95 dBA in hot aisles, requiring hearing protection and limiting technician exposure time. Direct Liquid Cooling facilities operate at 65 to 75 dBA, comparable to a normal conversation.

Rack density improvement

Air cooling supports 20 to 40 kW per rack in practice. Direct Liquid Cooling enables 100 to 200 kW per rack, a 5x density improvement that is critical for next-generation AI and GPU infrastructure (Uptime Institute / Introl, 2024).

Financial impact of DLC

DLC can lower cooling-related energy consumption by up to 72.4%, with analysis by CoolIT Systems suggesting potential annual savings of approximately $259,000 per MW of IT heat load (ScienceDirect, 2025).

2CRSi's DLC ready servers

The OCtoPus range

2CRSi believes since day one in liquid cooling solution to cool its servers. The OCtoPus is a range of servers based on OCP principles, containing servers in the 3 mains type of cooling systems, direct liquid cooling being one of them.

OCtoPus 2GG

The OCtoPus 2GG in 1OU 21" is composed of two blade nodes, two sockets for AMD EPYC™ 9004 processors. Our DLC servers are equipped with leak-proof blind mate connectors that need to be attached to the manifolds. This design was thought to make technicians work simpler during maintenance: no more pipes to disconnect, only pull the server back to remove it from the rack!