In-rack cooling refers to cooling systems that are often used in small data centers or in high-density areas inside large data centers, or to supplementary cooling systems used in high-density environments. The technology used in in-rack cooling systems leaves the cold and hot air with no choice but to move across the servers and the heat exchangers, respectively.
In-rack cooling offers an ideal computing environment, that is, a microclimate that is thermally neutral to other parts of the room.
Techopedia explains In-Rack Cooling
An in-rack cooling system cools down the servers placed within closed rack cabinets. Both the cabinets and the in-rack coolers have been developed specifically to avoid the mixing of warm and cold air, which is the factor that causes loss in almost all server rooms. This cooling system operates at a higher temperature than other types of cooling systems. This results in a better level of free cooling, which is cost-effective as well.
In an in-rack cooling system, the airflow paths are minimal, requiring a lesser amount of fan energy. Furthermore, the exhaust air is trapped at its hottest point, which maximizes the cooling coil's delta T.
Based on the product, this efficient cooling system utilizes refrigerant or chilled water as the cooling medium. Even though there are exceptions, most products tend not to bring liquid into the server rack. The air conditioner, along with the water connections, is encased in a nearby, but independent, enclosure. The device at the rack level continues to be air cooled. For chilled water supply in addition to best heat rejection, chilled water units require connections to the chillers.
In-rack cooling is versatile, quick to employ and attains high density with additional expenditures.
In-rack cooling offers the following benefits:
Agility: Can easily afford any power density
System availability: Close coupling results in the removal of hot spots as well as vertical temperature gradients
Lifecycle expenditure: Standardized elements and a pre-engineered system minimize or eradicate planning and engineering
Serviceability: Standardized elements lessen the need for technical expertise
Manageability: Effortless browsing through a menu interface and is good at providing predictive failure analysis