Server Room Cooling: A Guide to Server Room Air Conditioners

In today’s networked environment, server rooms are one of the indispensable parts of modern businesses. Even SMEs with more than a few workstations typically need a server, whether housed in a room or a closet.

And one thing that all servers generate is heat – lots and lots of it. These critical but fragile network equipment need lots of cooling and heat management in order to function efficiently and reliably. In this guide, we tackle everything you need to know about server room cooling, to ensure seamless operation of your office workstations, and by extension, your business.

What is a Server Room?

A server room is a dedicated space  designed to house computer servers and networking equipment. These rooms play a crucial role in IT infrastructure, since they contain the servers that are the backbone of the business or company’s network operations. 

Server rooms vary in size – small businesses may make do with a dedicated server or two housed in a closet, but larger businesses and commercial operations typically require a dedicated server room with industrial-grade protection. Some of the largest server rooms in the world, more formally known as data centers, are actually housed in impregnable bunker-like shelters to protect them from temperature extremes and humidity, with some even being housed underwater for maximum cooling!

One thing that all server rooms have in common is that they must be optimized for temperature, humidity, and airflow control to maintain peak server performance and prevent hardware failures. In other words: they must be constantly air conditioned.

Server Room Temperature and Environmental Standards

Maintaining proper temperature, humidity and ventilation is critical to ensuring the longevity and efficiency of server equipment. The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) provides guidelines for data centers and server rooms, based on ASHRAE TC 9.9, “Equipment Thermal Guidelines

for Data Processing Environments”.

These standards include:

🌡️ Temperature Range

ASHRAE recommends that server rooms operate between 64.4°F and 80.6°F (18°C to 27°C).

❄️Optimal Temperature

The ideal temperature for most server rooms is around 72°F to 75°F (22°C to 24°C).

🧊 Humidity Levels

ASHRAE suggests maintaining relative humidity between 40% and 60% to prevent electrostatic discharge (low humidity) and condensation (high humidity).

♨️ Airflow and Ventilation:

Proper airflow must be maintained to prevent hot spots, and cold aisle/hot aisle configurations are recommended.

Other Server Room Compliance and Building Codes

While ASHRAE governs the temperature and humidity control for servers, there are other regulatory and industry standards for server rooms:

Energy efficiency standards: Some regions also have their own local energy regulations that affect cooling systems, such as SEER (Seasonal Energy Efficiency Ratio) ratings.

The Different Cooling Methods for Server Rooms

There are various cooling methods to maintain the optimal temperature and humidity levels in a server room:

1. Air Conditioning Units (CRAC/CRAH)

CRAC (Computer Room Air Conditioning) Units: These function like standard air conditioners but with more precision cooling capabilities. They are also known as “room-based cooling”.

CRAH (Computer Room Air Handling) Units: These use chilled water systems to cool the air and are more energy-efficient for larger server rooms.

Both types must comply with Department of Energy (DOE) energy conservation standards 10 CFR 431.92. 

2. In-Row Cooling Systems

These cooling units are placed between server racks to provide targeted cooling. They are designed for high-density server configurations. 

According to the DOE, they are more efficient than room-based cooling since airflow paths are shorter, increasing efficiency and reducing power required.

3. Liquid Cooling Solutions

Uses liquid-cooled heat exchangers to remove excess heat directly from servers. They are more efficient for high-performance computing environments.

The National Renewal Energy Laboratory states that liquid cooling is more efficient because the heat capacity of liquids is orders of magnitude greater than air-based cooling.

4. Hot Aisle/Cold Aisle Configuration

A layout that positions server racks to direct hot air away from cold intake areas. This setup helps improve cooling efficiency and reduces energy costs by 10-35% according to the DOE.

5. Ventilation and Exhaust Systems

Proper ventilation ensures hot air is removed efficiently. Additional exhaust fans may be used for small server rooms with limited airflow.

6. Server Closet Cooling

For smaller businesses with only a single server, server closets are relatively simpler to cool. Heat dissipation can be managed using a portable AC dedicated for the purpose, such as these examples:

Kwikool KIB6021 Iceberg Series 60,000 BTU Portable Separated Air Cooling System

KwiKool’s Iceberg Series line of portable coolers is an ideal solution for server and IDF rooms. It offers a separated air system which helps to recirculate cooled air while expelling hot air. 

This 60,000 BTU (5 ton) model uses single phase, 230 volt electricity and is 27.325″w x 51″d x 53″h, with a recommended circuit breaker size of 50 amps. It is powerful enough to cool effectively either as a primary or backup air conditioning source. The condenser on the KIB6021 utilizes THD, KwiKool’s exclusive Twin Hyperdrive Technology which produces a high volume of air without belts and eliminates all of the maintenance associated with belts.

Standard features include three fan speeds, a 5-gallon condensate tank with overflow float switch for manual emptying as well as an internal high lift condensate pump for direct drain option, auto-speed which automatically sets the fan speed based on the heat load demand, filter dryer for moisture protection. The Iceberg Series also includes dual top ducting and Kwikool’s Exclusive I/O Integral Condenser that allows for a separate exhaust outlet and cooling source inlet. With the unique dual system, the cold air created is then pushed out into the server room and recirculated within the room, not removed.

Daikin FTXM24WVJU9 / RXM24WVJU9 24000 BTU Class 22.0 SEER2 Wall Mounted Atmosphera Series Single Zone Mini Split System

The streamlined, wall-mounted mini split delivers 21,600 BTUs cooling and 24,000 BTUs heating. With 12.0 EER2, 22.0 SEER2, and 10.0 HSPF2 ratings, this system ensures year-round server room cooling and compliance with DOE regulations. It uses the new R32 refrigerant.

The inverter technology in the Daikin Atmosphera system optimizes compressor speed, reducing energy consumption and temperature fluctuations. This ensures consistent cooling for your server with minimal power fluctuations. Cooling capabilities can be further extended to -4°F with a wind baffle and dipswitch adjustments. 

The system uses hybrid cooling that efficiently reduces humidity without overcooling. This maintains dehumidification for the server room after reaching the target temperature. It also boasts built-in WiFi, allowing you to control your system remotely with ease.

Best Practices for Server Room Cooling

1. Use Temperature and Humidity Sensors

Real-time monitoring ensures quick response to temperature fluctuations.

2. Redundant Cooling Systems

Having backup cooling prevents downtime in case of failures.

3. Seal Unused Rack Spaces

This stops hot air from recirculating into cooler areas of the room.

4. Regular Maintenance

Ensure filters, ducts, and cooling units operate at peak efficiency through periodic cleaning, or replacement if needed.

5. Consider Modular Data Centers

These pre-designed modules come with their own cooling systems, and are scalable and efficient for growing IT needs.

Conclusion

Proper server room cooling is essential to prevent overheating, equipment damage, and data loss. By following ASHRAE standards, utilizing efficient cooling solutions, and ensuring compliance with regulations, businesses can maintain a reliable and efficient IT infrastructure. Whether opting for traditional air conditioning, liquid cooling, or advanced airflow management, investing in the right cooling strategy will prolong the lifespan of servers and improve overall performance.