Data Center Cooling 101: From Start to Finish

Data center cooling attendant

Most data centers use a lot of electricity, especially when you consider the amount of computing power that fits into a single data floor. 

Because data centers can be so energy-intensive, it’s essential to have a sound data center cooling system in place. A data cooling center will help ensure that your electrical equipment does not overheat so your business can continue to run smoothly. 

What do you need to know about data cooling centers? Read on to learn the ins and outs of data cooling centers. 

What is Data Center Cooling?

So, what exactly is data center cooling? Data center cooling involves several techniques that aim to keep electrical equipment at the right temperature so it doesn’t overheat. 

When electrical equipment overheats, damage to the circuit components may result. This can lead to explosions, fires, and injury. Damage caused by overheating is usually irreversible, and the only way to repair the equipment is to replace some of the components. 

So, not only is keeping your data center cool essential for the efficiency of your organization, but it’s also essential for the safety of you and your employees. Data center cooling is a preventative measure that keeps your employees and your equipment safe. 

Related: About C&C Technology 

Types of Data Center Cooling Systems 

There are a variety of cooling techniques that you can implement in your data center. Here’s a look at some of the different systems available:

Chilled Water System 

This type of cooling system is commonly used for medium to large-sized data centers. This system uses chilled water to cool the air brought in by air handlers (also known as CRAHs). The water comes from a chiller plant that’s located somewhere in the facility. 

The CRAH units for chilled water systems tend to be affordable, contain fewer components, and have a higher heat removal capacity than other types of units. Another benefit is that as the data center capacity increases, so too does the efficiency of the chilled water system. 

These systems can be engineered to be highly reliable, and they can be combined with economizer modes of operation to increase efficiency. 

The only major downside to a chilled water system is its high capital costs for installation. This system also means you’ll be introducing an additional liquid source into your IT environment. 

Computer Room Air Handler 

A computer room air handler (CRAH) is another option for cooling your data center. However, a CRAH unit functions as a part of a broader system for cooling your data center, and it’s not a stand-alone cooling option. 

Chilled water moves through the cooling coil in the unit, and the unit then uses modulated fans to bring in air from outside the facility. Because CRAH units work by chilling outside air, they work best in places with colder annual temperatures. 

Computer Room Air Conditioner 

The computer room air conditioner (CRAC) is considered the alternative to CRAH units. These operate in a similar manner to conventional air conditioners, as they’re powered by compressors that draw in the air across a refrigerant-filled cooling unit. 

In terms of energy usage, CRAC units aren’t your most efficient option, but the equipment itself is relatively affordable. 

Evaporative Cooling System

Evaporative cooling systems work by exposing hot air to water. The exposure causes the water to evaporate, and heat is drawn out of the air. 

Because these systems use the natural evaporation process, they’re environmentally friendly, and they’re one of the most energy-efficient cooling methods available. If you’re looking to reduce your facility’s energy consumption, evaporative cooling is a great option. 

To facilitate evaporation, organizations often use data center cooling towers. This makes it easy to transfer the excess heat to the outside atmosphere. 

Calibrated Vector Cooling

This system focuses on optimizing the airflow path and managing heat. With calibrated vector cooling, cold air gets sent through the hottest and most crucial electrical equipment components. 

The goal of calibrated vector cooling is to use a small number of fans and a minimal amount of power while cooling as many servers per unit as possible

Cold Aisle/Hot Aisle 

This is a rack deployment method that involves alternating rows of hot aisles and cold aisles. The cold aisles come with cold air intakes on the front of the racks, while the hot aisles have hot air exhaust on the back of their racks. 

The hot aisles release hot air into the air conditioning intakes. This hot air then gets chilled and vented into the cold aisles. To prevent overheating and wasted cold air, empty racks are filled with blanking panels. This system is also sometimes referred to as in-row cooling. 


A direct-to-chip system cooling system uses liquid. This system uses pipes to deliver liquid coolant directly to a cold plate to disperse heat in the motherboard’s processor. 

The extracted heat then gets fed into a chilled water loop. It’s then carried away into the facility’s chiller plant. Since this system involves directly cooling the processors, it’s one of the most efficient options for data center cooling.

Raised Floor

This system involves using a frame to lift the floor of the data center above your building’s concrete slab floor. The new space created between the two floors is then used for increased airflow or to install water-cooling pipes. 

While network and power cables sometimes also run through the space, new data center cooling designs place these cables overhead. 

Immersion Cooling 

Immersion cooling refers to is a new system that involves submerging hardware into a bath of non-flammable, non-conductive dielectric fluid

Free Cooling 

Free cooling refers to any system that uses the outside atmosphere to introduce cooler air into the servers. On the other hand, non-free cooling systems work by continually chilling the same air. 

While free cooling can only be implemented in certain climates, it’s an extremely energy-efficient form of data center cooling. 

Liquid Cooling

Liquid cooling refers to any data center cooling system that uses liquid to remove heat from the air. More and more data centers are adopting liquid cooling systems that involve exposing server components to liquid to help them cool down faster (such as an immersion system). 

Related: C&C Technology Blog 

Air Cooling vs. Liquid Cooling in Data Centers 

The early versions of liquid cooling were messy, complicated, and expensive. However, with new advances in technology, they’re becoming a lot more streamlined and energy-efficient. 

More facilities are opting for liquid cooling over air cooling because air cooling requires a great amount of power. Not only that, but air cooling systems also introduce pollutants and condensation into your data center. 

On the other hand, liquid cooling is a lot cleaner, and it’s more scalable. Additionally, most air cooling systems usually require the use of large fans or other large pieces of equipment. If your data center is already strapped for space, air cooling may not be a viable option. 

What is the Ideal Data Center Temperature?

While you want your data center to be cool, you don’t want it to be too cold. Ideally, you want your server inlets to fall between 64.4 to 80.6 degrees Fahrenheit (or 18 to 27 degrees Celsius). Relative humidity levels should fall between 20 and 80 percent

Also, keep in mind that the above temperatures are for server inlets, not for the data center itself. Typically, the air around the servers will be warmer than the actual server inlets due to the dynamics of heat transfer. So, if your room falls above 80.6 degrees, don’t panic. 

Also, remember that high-density servers generate a large amount of heat. That’s why most facilities keep their server rooms colder than the above limits. 

It’s also important to note that hyper-scale data centers run by large organizations like Google tend to run at higher temperatures (sometimes closer to 80 degrees Fahrenheit). 

This is because they run on an expected failure model. In other words, they expect that servers will fail on a regular basis, so they have software backups in place to route the failed equipment. 

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Tips for Optimal Data Center Cooling 

For your data center to cool at optimal levels, we recommend following these tips:

Use Containment Measures 

Air has a tendency to move wherever it wants. Installing walls and doors and implementing other containment measures will ensure the cold air stays where it needs to be. 

Efficient containment will also allow your data center to run higher rack densities while at the same time reducing energy consumption

Use Hot/Cold Aisle Design

Regardless of the cooling system you choose, the hot/cold aisle design can take your cooling efficiency to another level. 

Conduct Regular Inspections

Water damage can be a huge problem for data centers, and it’s one of the leading causes of downtime and data loss. 

Also, water damage usually isn’t covered by business insurance policies. And even in cases where it is, there’s still no way to replace the lost data. 

The good news is that it’s easy to detect most leaks. You can use tools such as zone controllers, fluid and chemical sensing cables, and humidity sensors to spot leaks before they become a bigger problem.

Synchronize Humidity Control Points 

Synchronizing humidity control points is another important step for creating an optimal data cooling center. Most data centers make use of free air-side cooling through air-side economizer systems. 

These systems introduce air from the outside into the data center to improve energy efficiency. The downside is that they can also bring in moisture, which can lead to condensation and the corrosion of electrical systems. 

While adjusting climate controls may seem like the solution to this problem, doing so can lead to even more issues. Instead, you should make sure your humidity controls account for the moisture coming into the data center from the outside. This will allow you to maintain an ideal environment in the room. 

Data Center Cooling Mistakes to Avoid

In addition to the above tips, there are also some cooling mistakes that you need to avoid. These include:

Empty Cabinets 

Empty cabinets can mess up the airflow of your data center. This can cause hot exhaust air to leak back into your cold aisles. If your data center does have empty cabinets, make sure the cold air is contained. 

Poor Cabinet Layout 

As we mentioned, a smart cabinet layout incorporates a hot and cold aisle design. Your computer air handlers should also be placed at the end of each row. 


As we discussed above, leaks can be another major issue for data centers. There are two types of leaks you need to watch out for: raised floor leaks and leaks around cable openings. 

Raised floor leaks happen when cold air leaks under the raised floor and into the support columns of adjacent spaces. The leaks can result in a loss of pressure, which and dust, warm air, and humidity can enter your cold air environment. 

Leaks around cable openings can result if there are holes under the remote power panels, unsealed cable openings, or holes in the power distribution units. 

Multiple Air Handlers Trying to Control the Humidity 

If one air handler is trying to dehumidify the air while another one tries to humidify it, it can result in a lot of wasted energy. This is why you need to thoroughly plan your humidity control points, as this will reduce the risk of this issue occurring. 

Data Center Cooling FAQs

Do Data Centers Need to Be Cold?

There’s no doubt that servers tend to produce a lot of heat. If data centers overheat, this will instantly destroy efficiency, thus causing a lot of mishaps. Therefore, data centers need to be cooled off; there isn’t any other way around this. The more traditional data centers are cooled through a hot and cold aisle, which is the layout of the server racks that creates this combination between heating and air conditioning. 

What are the Types of Cooling Systems Used in Data Centers?

The following are some of the more popular methods that are used in data center cooling. 

  • In-Rack Heat Extraction
  • Hot Aisle Containment
  • Evaporative Cooling
  • Liquid Immersion Cooling
  • Standing for Computer Room Air Conditioner (CRAC)

While these are the more popular methods for cooling off data centers, the traditional method tends to get used the most.

What is the Ideal Temperature for a Data Center?

There has been some debate on the optimal temperature for a data center within the tech industry. While there isn’t a precise temperate, it’s usually favored that anywhere around 68 to 71 degrees Fahrenheit is considered the most comfortable.

Related:  Data Center Fire Suppression: Overview & Protection Guide

What is the Max temperature for a Server Room?

Server rooms should never go above 89.6 degrees. This can lead to overheating. Therefore, it’s best to keep the data centers within the range of 59 degrees to 89 degrees Fahrenheit. 

Do Data Centers Use Water Cooling?

Water cooling is quite common in data centers. You’ll find that the average data center will use around three to five million gallons of water for the data center every day. While this is the industry average, it could vary per data center. 

Do Data Centers Reuse Water?

Since data centers will use roughly around three to five million gallons of water each day for the data center for water cooling, it’s fair to wonder if data centers will also reuse the water. For example, data centers can build their wastewater treatment system, then reuse water. Alternatively, a third-party operator could build and operate a wastewater treatment plant to help with the water costs.

How Does Direct Liquid Cooling Work? 

Liquid cooling is another method for cooling down a data center. It’s usually referred to as DLC or direct liquid cooling. This uses the exceptional thermal conductivity of liquid to provide concentrated cooling to targeted areas. Usually, it will be warm water, and it can help lower costs and other power-related expenses.

What is Direct Chip Liquid Cooling? 

Direct chip liquid cooling means that the liquid coolant is sent through tubes, which then go to the chip afterward to get absorbed. Afterward, it gets heated in the data hall, where it gets removed. This is considered a very effective way of removing heat. 

Are you thinking about how you could optimize your data center? Then schedule a call with us today, and find out what we can do for you!

Can a Server Get too Cold?

While the heat within the data center should go above 89.6 degrees Fahrenheit, it’s also important to recognize that there is such as thing as being too cold. Therefore, your data centers and servers should not exceed 50 degrees Fahrenheit.

Need Data Center Cooling? Call C&C Technology

Now that you know more about data center cooling, it’s time to take the next steps. Your next step should be to find a data center partner that can help you build your data center with efficient cooling systems. 

Last Updated on January 20, 2023 by Josh Mahan

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