As an efficient way of cooling data centers, liquid cooling solutions are addressing the increasing heat issues which have resulted from enhanced processing speeds.

FREMONT, CA: With the rise of technologies such as artificial intelligence (AI) and the internet of things (IoT), requirements of the data centers have grown rapidly. Increased processing capabilities are further propelling enterprises to heighten their storage capabilities. However, the powerful chips incorporated by the companies in their data centers release significant amounts of heat. Liquid cooling addresses the heat issue, as the specific heat capacity of liquids is higher than that of air. Furthermore, once the heat is transferred to a liquid, it can be removed from a data center efficiently.

In the case of air-based cooling, cold air requires to be separated from the hot air in the data center. It is done by shifting the cold sides of the server cabinets away from the hot sides. Air-based cooling has been the salvation for data centers as air distribution to IT equipment directly influences the efficiency and lifespan of the equipment. Such a transfer of heat may be as uncomplicated as using an exhaust for cooling or sophisticated systems containing separate hot and cold aisles.

Some data centers use an enclosed space comprising all the components of the refrigeration cycle, which can be seen as self-contained systems. The major benefit of opting for an enclosed system for the data centers comes from the economical cost of installation. However, there are constraints of using such a setup, as the heat removal capacity is comparatively lower than other configurations used in data centers. Another necessity of an enclosed system is that it requires ductwork or dropped ceilings to facilitate air channelization. Besides, the major difficulty with air-based heat cooling is to stop the warm and the cold air from mixing.

Liquid cooling provides an alternative to the standard means of cooling. It offers various benefits over the air-based cooling methods. Immersion cooling is another variation of liquid cooling. It is much more productive, leading to highly improved data center performance and economics. Heat is transferred directly from the heat source to the working fluid in case of immersion cooling. Against the water cooling techniques that always carry a risk of affecting the sensitive data center components with possibly harmful fluids, immersion cooling uses non-conducive working fluid.

A range of liquids can be used in the event of Immersion cooling. Nonetheless, based on the features of the coolant, immersion cooling can be classified into Single Phase Immersion Cooling and Two-Phase Immersion Cooling. A single-phase coolant does not change its state, i.e., it never freezes or boils. The coolant gets transferred to a heat exchanger where the heat is transferred to a cooler water-circuit. The open-bath method is used in the case of single-phase cooling, which necessitates fully submerging the servers in dielectric coolant fluid.

In the case of two-phase cooling, the operating fluid endures in both liquid and gaseous phases. The system takes benefit of ‘latent heat.’ A liquid necessitates some amount of heat to transform into the gaseous form, terming the heat required as the latent heat. The operating fluid has the propensity to cool naturally after boiling. The energy transferred from the heated data equipment retains the fluid in the boiled state. The vapor rises and comes into the contact of a condenser that is cooler than the saturation temperature. It causes the vapor to condense back into its liquid form, hence continuing the cycle.

The liquid-based data cooling solutions seem a little expensive than air-based cooling systems. However, it can be an excellent option for businesses looking for reliable and robust data cooling solutions.