Cooling of data centers

In recent years, several technologically advanced solutions have emerged to address the new cooling needs of data centers, server rooms and DPC. Liquid cooling systems, in particular, have become a sophisticated solution, available in both direct-to-chip version (cooling only specific components such as chipsets and GPUs) and immersion cooling (where all server components are submerged in a dielectric liquid).

Whilst liquid cooling systems offer enhanced thermal efficiency and reduced energy consumption, particularly in view of the increased computational demands and the use of more powerful microprocessors, they are not considered definitive solutions. It is estimated that approximately 10-20% of heat generated is still released into the air. Consequently, contemporary designs incorporate “hybrid” solutions that seamlessly integrate liquid and air-cooling systems.

The Hybrid Rooms: a profile of an efficient and sustainable solution

A combined solution must harness the synergy between air and water cooling to reduce inefficiencies and ensure maximum operational continuity for data centers. The following are some possible components.

Dry cooler

A dry cooler is a cooling device that uses an air-to-air heat exchanger to dissipate heat. The underlying principle is thermal exchange: first, heat is absorbed from CPUs and GPUs. Then, a process liquid (coolant for IT equipment, usually water or a water/glycol mixture) is introduced into the dry cooler.

Here, the heat is transferred to the airflow generated by fans, which is then expelled while the fluid continues its cooling cycle. This approach not only conserves water but also reduces overall costs and minimises resource consumption (both water and energy), making it a highly efficient solution for data center cooling.

FanWall dual cooling

Fanwalls (perimeter air conditioners) are a type of cooling system that are installed along the perimeter of rooms. These systems function by drawing in hot air generated by servers and IT equipment, processing it through a cooling system, and redistributing it evenly within the room.

The cooling system can be of the air-to-air, air-to-water or, in dual cooling systems, include a double mechanism, such as an evaporative coil and chilled water from an external unit (e.g. chiller). The hybrid system has been developed to address the redundancy issue of liquid cooling systems. In the event of the primary system failing to lower the temperature of a single rack, this could result in the interruption of operations for the entire server. The presence of two systems significantly reduces the risk of overheating in case of a failure and allows for the selection of the most cost-effective operational solution at any time.

Coolant Distribution Unit (CDU)

The Coolant Distribution Unit (CDU) is a device that is utilized for the distribution of coolant within the data center, with the objective of maintaining it within temperature ranges that ensure the efficiency of the cooling system and the longevity of the equipment. The CDU functions as an intermediary between liquid cooling systems and IT equipment, thereby assuring that each rack receives the requisite amount of coolant. This is facilitated by a pump system that maintains continuous flow to and from the heat exchanger.

Rear Door Heat Exchanger

Rear Door solutions constitute a range of cooling systems that have been specifically designed to reduce temperatures directly at the back of racks, where server-generated heat is most intense. These systems can be classified into two distinct categories: active and passive. The former incorporates fans to augment airflow, whereas the latter relies exclusively on natural airflow. The efficacy of these systems in reducing temperature is substantial, thereby enhancing the overall energy efficiency of data centers.

HiNode

HiNode represents a sophisticated monitoring and management apparatus conceived to oversee all components and devices within a data center’s cooling system. In essence, it functions as a centralized
interface, facilitating the management of all units and devices, thereby optimizing functionality and coordinating air and water systems.

The advent of hybrid solutions has precipitated a paradigm shift in the realm of data center cooling, increasing technological complexity and system efficiency. For comprehensive and customized solutions, spanning the entire life cycle from design to implementation and installation, please contact HiRef, a leading technology company specializing in IT infrastructure cooling since 2001.