09 October 2025
Mark Yeeles, Vice President, Secure Power division, Schneider Electric UK & Ireland
The accelerated computing trend, and artificial intelligence (AI) in particular, has driven equipment and energy density in data centres like never before. 
Power per rack has reached averages of 12kW in 2024, with 30kw not uncommon. AI systems have been observed drawing 130kW/rack, with certain development roadmaps expected to see 600kW per rack in 2027.
Practically speaking, even with close management such as hot aisle/cold aisle set ups, air cooling begins to lose efficiency and effectiveness from the 30kW per rack stage. That is why liquid cooling is being adopted so widely as it offers greater opportunities for efficient, targeted, and tightly controlled cooling.
As most data centre owners and operators don’t have the luxury of starting with a clean slate, liquid cooling is being adopted incrementally with direct to chip (DTC) options that can be retrofitted to existing equipment. For example, a metal plate in contact with the processor, CPU or GPU, that allows a liquid cooling medium to circulate through it, draws the heat away and can exhaust it through a cabinet rear door heat exchanger. This works well and can be implemented fairly quickly. It is compatible with the hot aisle/cold aisle configurations and provides immediate access to the benefits of the technologies.
The next stage is for DTC to be supported by coolant distribution units (CDU), and this can be scaled fairly readily for racks, rows, and entire halls, as needed. If new halls or facilities are being built or fitted out, CDUs can be integrated into designs to provide more flexible and robust distribution of the cooling medium and can be used for servers, networking or storage equipment as needed. However, when going down this route, specialist skills are required for design, implementation and operation.
The advantage of using liquid cooling in this manner is that tighter tolerances in terms of equipment operating temperatures, as well as equipment controls, can be used. The chips can be run at higher but safe temperature ranges, increasing efficiency and also reducing overall consumption. Also, the closed systems allow for greater instrumentation, meaning more scope for analysis and automation using AI-assisted data centre information management (DCIM) systems. This means that systems can be constantly monitored and optimised for performance and availability, but also for efficiency and sustainability goals. There are instances of overall compute power consumption being significantly reduced through software and data analysis facilitating optimisation.
Another option in liquid cooling is immersion cooling. This is where the equipment up to entire servers are immersed in a non-conducting cooling medium that is then circulated out to heat removal devices. Immersion cooling is not really suitable for retrofitting, due to its complexity, and requires specially design equipment to take advantage. This technique is more commonly seen in high performance computing (HPC) and supercomputer set ups, but it has its uses and advantages.
A significant challenge for those who wish adopt liquid cooling is a lack of standardisation in the available options. It can be difficult to get equipment to suit a particular implementation, and bespoke elements are common with cost implications. This has led some vendors to partner closely with, or acquire, liquid cooling providers to ensure portfolio alignment, reducing adoption risk for data centre owners and operators. This is a good option as it ensures compatibility, quality and service standards that all feed into assurance of reliability, resilience and availability.
Another significant advantage for liquid cooling is that the nature of the techniques provides greater scope for practical heat recovery and reuse. This means that even with high density equipment and its intense cooling requirement, sustainability goals can be met and accommodated. Heat reuse can be local within the data centre or campus or can connect to the likes of district heating schemes for either homes or leisure facilities. In some cases, heat reuse is being explored for agri- and aquaculture purposes, as well as for environmentally friendly fuel production in wood pellet drying processes. Examples of market gardening and fish farms using recovered heat energy already exist.
Liquid cooling is the accessible and practical answer to today’s energy and equipment density challenges. If the issues of standardisation and compatibility can be resolved, liquid cooling presents data centre owners and operators with a range of options to ensure efficient, sustainable support of compute intensive workloads while also facilitating sustainability ambitions.
