Rack Enclosure Thermal Management: 5 Cooling Methods

Rack enclosure thermal management helps control the heat generated by servers, electronics, and other equipment housed inside an enclosure. The appropriate cooling method depends on factors such as ambient temperature, internal heat load, environmental conditions, and the maximum operating temperature of the enclosed equipment.

Why Is Thermal Management Important for Rack Enclosures?

When installed inside of a server rack enclosure, there are many factors that can affect the performance of electronics.

Popular reasons for using thermal management, include: environments that are hot and dirty or electronics that produce a good amount of heat inside of an enclosure. 

For example, if the temperature outside a rack enclosure will reach 110° F or above, the internal components must be kept at a cooler temperature. However, proper cooling or ventilation is dependent on the environment and contents of the rack enclosure.

The thermal management system should be selected based on the actual operating conditions and temperature requirements of the equipment rather than a single ambient-temperature threshold.

Why is cooling such an important factor in a rack enclosure solution? 

At the beginning of a project, if thermal management is not properly configured, several things could go wrong with the enclosed electronics. Faults in electrical components and overloads may lead to a tripped breaker, decreased life expectancy, or an unexpected equipment shutdown.

Planning for enclosure thermal management early can help reduce overheating, unexpected shutdowns, and other heat-related equipment problems.

What to Consider Before Choosing a Cooling Method

Before choosing a thermal management system, consider:

• Ambient temperature around the enclosure
• Maximum allowable temperature for the enclosed equipment
• Heat generated by equipment inside the enclosure
• Dust, dirt, water, and other environmental contaminants
• Required NEMA rating
• Available power or compressed air
• Maintenance requirements

5 Types of Cooling Methods for Rack Enclosures

1. Vents and Louvers

The simplest method of enclosure cooling is utilizing a vent or louver to provide natural convection/airflow. Natural convection cooling occurs as warm air rises and is replaced with cooler air.

Generally, louvers are added at the top for hot air to escape and at the bottom for cooler air to be drawn into the enclosure.

When does it make sense? The maximum ambient temperature must be cooler than the maximum allowable enclosure temperature.

2. Fans

Forced ventilation moves air across the enclosure to increase the cooling rate compared with vents. Fans can produce a higher airflow rate than natural convection cooling.

When does it make sense? The maximum ambient temperature must be cooler than the maximum allowable enclosure temperature. Filtered fan systems can also help limit particulate matter entering the enclosure while providing airflow.

3. Heat Exchangers

Heat exchangers use a closed-loop cooling system. The air inside of the enclosure is cooled and circulated without the exchange of ambient air.

When does it make sense? The maximum ambient temperature must be less than the maximum enclosure temperature. Depending on the construction, a heat exchanger may be used in a NEMA 12, 4, or 4X environment.

4. Vortex Coolers

Vortex cooling units use compressed air to cool internal components and displace warm air inside of an enclosure.

When does it make sense? A vortex cooling unit is not a closed-loop system but may be used with NEMA 12, 4, or 4X enclosures.

These units also create positive pressure inside of the enclosure, so that dust and other particulate matter will not be drawn into the cabinet. There are no moving parts, so the lifetime is much longer than most thermal management systems and there is very little maintenance.

5. Air Conditioners

Air conditioners are another common closed-loop cooling system. The inside of the enclosure is cooled by an evaporator coil and circulated without mixing outside air.

When does it make sense? Air conditioners can provide greater cooling capacity than passive ventilation or many fan-based systems and may be appropriate when the required internal enclosure temperature cannot be maintained using ambient air alone.

However, due to the compressor, air conditioners tend to be large in size.

How Do Rack Enclosure Cooling Methods Compare?

Cooling Method	Uses Ambient Air?	Can Cool Below Ambient?	Typical Consideration
Vents/Louvers	Yes	No	Simple passive airflow
Fans	Yes	No	Greater airflow than natural convection
Heat Exchanger	No	No	Separates internal and ambient airflow
Vortex Cooler	Compressed-air based	Yes	Requires compressed air
Air Conditioner	No	Yes	Active cooling for higher heat loads

Choosing the Right Thermal Management System for a Rack Enclosure

Maintaining appropriate operating temperatures inside a rack enclosure can help protect sensitive electronics and reduce the risk of heat-related equipment problems. The right thermal management method depends on the equipment heat load, ambient environment, allowable internal temperature, enclosure requirements, and available utilities.

Knowing all of the options that exist for rack enclosure cooling, along with the benefits and limitations, will help you make the best choice for the application.

Need help determining the cooling requirements for your rack enclosure? Complete the Cooling Requirement Worksheet and talk with an ITSENCLOSURES specialist about your application. You can also explore our industrial rack enclosures for equipment protection in demanding environments.