Server Rack Cooling Solutions: In-Rack and In-Row Cooling

Posted by Stephan Lam on December 1, 2023

Traditional computer room air conditioning (CRAC) units are struggling to keep up with the heat generated by today’s power-hungry IT equipment. These systems circulated chilled air throughout the room, wasting much of the cooling capacity on empty space. Raised-floor cooling and aisle containment systems help reduce the amount of space and prevent chilled air from mixing with hot exhaust air. However, these approaches alone won’t meet the demands of today’s high-density data center. 

Operators are exploring new data center cooling techniques to meet evolving demands. In-rack and in-row cooling can help data center operators improve cooling efficiency. These solutions help ensure that chilled air reaches the IT equipment while reducing the load on CRAC units. 

In-Rack Cooling Solutions

In-rack cooling provides the most precise means of delivering chilled air to IT equipment. The cooling unit is placed directly in the server cabinet, minimizing the amount of space that must be cooled. Because the airflow path is extremely short, very little energy is wasted. All of the chilled air moves across the equipment, dissipating heat quickly. This allows for the highest possible power density.

Refrigerant-based rack cooling units may be mounted on top of or beside the cabinet or horizontally within the cabinet, like IT equipment. Chilled-water units are installed in a separate, adjacent enclosure, often in a rear-door panel. Hot exhaust air passes through the chilled water and into the room at ambient temperature. The unit requires a connection to a chiller.

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In-Row Cooling Solutions

In-row cooling systems provide one or more dedicated cooling units for a row of server cabinets. Like in-rack cooling, in-row systems may use refrigerant or chilled water. The units may be installed overhead, under the floor, or within a row of cabinets. The latter type is typically the height of a server cabinet and about half the width. 

Chilled air is directed from the cooling unit to the cabinets, with up to 95 percent efficiency. Hot air exhausted from the backs of the server cabinets may be collected in a hot-aisle containment system and delivered outside or directed into the rear of the cooling unit. Close coupling ensures that the cooling unit captures exhaust air at its hottest point for maximum efficiency.

To optimize the value of in-row cooling, data center operators should match the cooling unit’s capacity to the IT equipment’s needs. High-density cabinets should be placed together in a row with redundant, high-capacity cooling units. Lower-density cabinets should be placed separately with an appropriately sized cooling unit. Close coupling combined with hot-aisle containment offers the greatest efficiency.

Benefits of In-Rack and In-Row Cooling Systems

In-rack and in-row cooling solutions require a more significant capital investment than CRAC units because more units are required. The cost per watt of power decreases dramatically as rack density increases due to greater efficiency. However, initial costs remain higher than room-based cooling.

These investments can be recouped quickly with lower operating costs. In-row cooling requires less power than room-based cooling, particularly when combined with hot-aisle containment. In-rack cooling requires more power than room-based cooling at lower densities, but the power requirements drop dramatically over 6 kW per rack. This helps reduce operating costs and helps meet sustainability objectives.

In-rack and in-row cooling make data centers more scalable. Servers can be added to existing racks without the need for additional cooling. In-row cooling also makes it feasible to install extra standby cooling units to provide redundancy for mission-critical workloads.

Additionally, rack or row-level liquid cooling solutions are available to run alongside or in conjunction with existing air cooling instead of investing in a major infrastructure overhaul.

Server Rack Cooling Options from Enconnex

The Enconnex EdgeRack line of micro data center cabinets features highly efficient in-rack cooling. The EdgeRack 3P is equipped with 3.5kW of cooling capacity, the EdgeRack 5M comes with 5 kW of cooling capacity, while the EdgeRack Industrial 8M delivers up to 8kW of cooling capacity along with NEMA 12 and IP55 ratings. 

The Enconnex InfiniRack data center cabinet is a great option for in-row cooling architectures. With excellent load ratings and a design that maximizes usable internal space, InfiniRack can support high-density environments. We configure it to order to meet your requirements. Get in touch to explore solutions today.

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Posted by Stephan Lam on December 1, 2023

Stephan has over 15 years of IT experience, including all aspects of data center operations, project management, service delivery, and sales engineering.

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