A Guide to Data Center Cooling Technology – Clean Air Solutions

Feb 19 2020

Interior of a Data Center - Clean Air Solutions

Data centers and clean air solutions make up the backbone of the internet’s infrastructure. They house the network systems necessary to facilitate the transfer of data.

Without data centers, simple operations, such as sending messages online, would be impossible. Additionally, many businesses that rely on digital infrastructure – and all companies are becoming increasingly dependent on the digital world – would also suffer disruptions to their operations.

The network systems housed in data centers comprise computer hardware components, such as servers and chips. These hardware components utilize a lot of energy and, as a result, they produce a lot of heat. Temperature regulation is one of the main maintenance requirements of data centers as too high or too low temperatures cause complications that disrupt a data center’s operations.

Data Center Cooling Technologies

There are over a dozen temperature regulation solutions for data centers. Some of these cooling technologies are traditional and simple, while others are modern and quite sophisticated. The ideal cooling technology depends on factors such as the data center’s size. Here is an insight into the various data center cooling technologies.

Computer Room Air Conditioner (CRAC)

Computer Room Air Conditioner (CRAC) is one of the simplest and most common data center cooling technologies. It functions similarly to an ordinary HVAC system.

CRAC cooling technology regulates temperature by using a compressor to draw air across or through a refrigerated cooling unit. This way, heat from servers and other equipment is cooled as air is circulated around the room. This technology can also be used to facilitate clean air solutions, which is another important maintenance requirement for operating a data center.    

CRAC cooling technology is not as efficient as other technologies, and as such is recommended for small data centers. Additionally, this technology is inefficient when it comes to energy usage, so it may cost you more than other technologies, in the long run, relative to size and other factors.

Computer Room Air Handler (CRAH)

Computer Room Air Handler (CRAH) cooling technology is a more sophisticated version of the CRAC cooling technology. Unlike the latter whose air regulation is limited to the inside of the data center room, CRAH cooling technology draws in cool air from the outside. The air drawn from the outside is passed through a refrigerated cooling unit. It is also commonly coupled with a chilled water system to facilitate cooling. The cooled air replaces the hot air inside and cools the temperature. It also helps facilitate clean air solutions.  

CRAH technology is more efficient than CRAC technology, but its efficiency depends on the data center’s location. This technology is best suited in cold places, such as the arctic, where the air is naturally cool, since it draws in air from the outside.  

Free Cooling

Free cooling is one of the simplest and most efficient data center cooling technologies. It works by replacing hot air inside the data center with cold air from the outside. However, this simplicity comes with one major complication – this technology only works in cool climates where the air is naturally cold. However, it can be combined with other technologies to adapt to certain environments, but a naturally cool environment is always an advantage.

Cold/Hot Aisle Cooling

Most mid-size and large data centers use cold/hot aisle cooling technology as their main temperature regulation solution. It is efficient and cost-effective, and to some degree simple compared to other sophisticated cooling technologies.

This technology uses alternating rows of cold and hot air isles. The cold air isles are positioned in front of the racks holding the servers while the hot air isles are positioned at the back. The cold air isles channel cold air towards the servers while the hot air isles channel hot air away from the servers. The hot air is then passed through a chilling unit and then channeled back through the cold air aisle. As such, the computer equipment remains constantly cool.  

This technology is efficient since it does not regulate all air inside the data center room. Empty spaces on the racks are filled with blanking panels to prevent cold air from going to waste.

Evaporative Cooling

Evaporative cooling technology, as the phrase implies, uses cold water to regulate temperature. It is a simple and efficient data center cooling technology.

The hot air inside the data center is exposed to cold water, which makes the latter evaporate. The cold vapor then absorbs heat from the air inside the data center. The heated vapor is then expelled into the outside atmosphere, and cold air is channeled in to replace it. The cold water used to regulate temperature in data centers may be introduced using a variety of channels. Common channels include wet materials, such as rags and mats, and misting systems.

Evaporative cooling doesn’t use CRAC and CRAH technologies, so it is energy-efficient – it, however, uses a lot of water. However, it may cause complications with humidity from the water vapor – too much humidity may cause rusting, corrosion, and short-circuiting.

Raised Floor

Raised floor cooling technology is often used as a supplement for other data center cooling technologies. A frame is used to lift the data center floor – basically, the racks and computer equipment is placed on a frame sitting above the floor. The space between the frame and the floor is then used to host cooling pipes and increase airflow, which in turn improves temperature regulation. The space may also be used to run cables through – this helps solve the issue of entangled cables, but it also may compromise temperature regulation by taking up space for air and other coolants.   

Direct-to-Chip Cooling

Direct-to-chip cooling is one of the most effective and efficient ways of cooling temperatures in data centers. It is also one of the most sophisticated.

As the phrase implies, this technology directly targets the chips on servers and other computer equipment – chips and processors are responsible for generating over 90% of the heat. Small pipes are used to channel coolants directly to the chip. The extracted heat is then passed through a chilled water loop in the data center’s chilling plant.   

Liquid Cooling

Liquid cooling technology is not as common as other data center cooling technologies mostly because of its level of sophistication – this, however, is set to change in the near future as the technology is expected to pick up momentum. It uses cool liquids to absorb the heat from servers and other computer equipment in the data center. The setups vary depending on a variety of factors. Modern liquid cooling technology solutions directly target chips and processors in the servers, thus eliminating the need for HVAC systems.  

Liquid cooling is complicated because liquids are generally bad for electronics, including servers. Leaks may compromise the whole data center since the different gadgets are usually interconnected. This technology is mostly recommended for large data centers.

Immersion System  

Immersion system cooling technology is a more sophisticated version of liquid cooling technology. This technology literally immerses the servers and other computer equipment whole into liquid, hence the name immersion system. The liquid used is non-conductive, so it doesn’t pose a threat to the electronic equipment. The liquid is also non-flammable, so there are no risks of fires.

Immersion system data center cooling technology is still new and so sophisticated that it demands a whole new setup of the data center. It is recommended for large-scale data centers to facilitate important communication. It also eliminates the need for clean air solutions since the servers are not exposed to the air.

Common Mistakes to Avoid with Data Center Cooling Solutions

Mistakes with data center cooling solutions are unavoidable – downtimes in data centers, which essentially means downtimes with the digital infrastructure, cost the average business about $5,500 per minute, according to research. Unfortunately, mistakes are common. These mistakes are also avoidable. Common mistakes to look out for include:

Empty Spaces

Empty spaces in data centers create room for hot air to be trapped and cold air to be wasted. They reduce the efficacy of data center cooling technologies. They also compromise clean air solutions as they just create more space for dust and debris to settle. Consequently, they also raise the chances of all possible complications from high temperatures occurring. As such, there shouldn’t be empty spaces between the servers – empty spaces in racks and cabinets should be sealed off using panels.

Empty spaces are not a problem when using certain cooling technologies, such as liquid cooling and immersion systems. However, all cooling technologies that rely on air regulations are susceptible to this mistake.

Bad Cabinet Layout

The cabinets and racks holding servers and other computer equipment should be designed to host cooling technologies such as hot/cold aisle cooling. A bad layout can compromise the entire room and necessitate restructuring – considering the expenses associated with setting up data centers, this is an unaffordable mistake.

It is important to have a complete and comprehensive plan for a data center before beginning the setup. Every factor should be planned for, and the racks and cabinets should utilize the latest innovative and flexible designs to accommodate a wide range of cooling and clean air solutions technologies.


Leaks are a major problem when using liquid data center cooling technologies. Liquids, as is common knowledge, do not mix well with electronics. Servers in data centers are interconnected to function as a single unit, so any exposure to liquid in one server can potentially compromise the whole setup. The risk is greater now that liquid cooling solutions target specific components such as chips and microprocessors. This is why there shouldn’t be any leaks with the liquid cooling systems.

Technicians have come up with an innovative type of liquid that is anti-conductive and anti-flammable. Data centers should consider utilizing this liquid to avoid any complications in case leaks occur.   

Use of Multiple Air Handlers

As mentioned, humidity control is an important aspect of clean air solutions. Just like temperature, the room’s humidity level should be optimal.

Air handlers help regulate the humidity in a data center. Using multiple air handlers may compromise humidity control – this happens when one handler works to increase humidity while another works to lower it.

Large data centers require two or more air handlers to regulate temperature. In such cases, it is recommended to install a stand-alone humidity control system independent of the air handlers. The system should compete with other clean air solutions, so customization may be necessary.

Clean Air Regulation – Another Important Maintenance Requirement

Stellar sanitation is just as important as optimal temperature regulation for data centers. The air in data centers should not only be cool but also clean. This is because dust and other small particles in the air can severely compromise the data center’s equipment. Research shows that dust on servers can raise the equipment’s temperature by as much as 300F. This raises the need for clean air solutions.

Humidity is also a big factor for data centers. Too much humidity can result in complications such as short-circuiting and rusting, while low humidity can lead to electrostatic complications. The optimal humidity level of a data center room should be between 45% and 55% of the air.

Clean air solutions ensure that there is no dust or any other contaminants in the air circulating around the data center room. They utilize a variety of technologies to filter out the fine particles from air. To this end, data centers require sophisticated HVAC systems.

In addition to filtering out contaminants in the air, it is also important to clean the servers and equipment regularly. There are clear guidelines on how to clean the equipment without compromising it. There are special solutions used to ensure that complications such as short-circuiting, which is likely to happen when using certain solutions, do not occur.


Data centers keep the wheels of the internet – and the digital world at large – turning. The world cannot afford to have data centers go down. Heat is one of the greatest threats to data centers, so it is important to utilize efficient data center cooling technology. Clean air solutions are necessary to ensure that dust and other contaminants dp not contaminate the air. Clean air solutions also ensure optimal humidity levels.