Unique changes in technology and the energy used to run these important pieces of equipment have created a need for new and innovative cooling methods for data centers. Cooling methods were first designed over three decades ago, when it was next to impossible to predict the needs of the current time. When a data center is being designed, there are several different options for cooling methods. Because data centers consume almost forty percent of the total energy when cooling off the center, it’s essential to find the most energy efficient method when designing a data center.
Data Center Cooling Issues
Most data centers face several problems when creating a cooling system.
First, it is necessary to understand the power density needs for the IT equipment in every data center. IT equipment is changing regularly and has updated needs for cooling depending on the equipment. When designing a cooling system, it’s necessary to create a system that can handle the current equipment, and account for changes in future equipment. Cooling systems should be flexible enough that they can adapt to future upgrades to your IT systems.
Second, cooling requires the second highest amount of energy that every data center uses. When designing a center and choosing a cooling system, it’s essential to choose a system that efficiently uses energy to cool the equipment and the center overall.
Finally, it is necessary to completely understand the airflow in the space, and also be able to control for the airflow at all times. The purpose of a cooling system is to avoid hotspots and increase efficiency by ensuring that the right environmental conditions are constantly in place. It is also necessary to understand that the server’s heat load and heat rejections are all part of one process and not two separate needs.
When searching for the right cooling system for a data center, there are three key components to keep in mind: scalability, agility, and environmental friendliness.
Chilled Water System
For data centers with availability requirements that run from moderate to high, a chilled water system is available in three different types:
- Glycol-cooled chillers
- Air-cooled chillers
- Water-cooled chillers
Each method is different based on how the particular system rejects heat using water or air. A chilled water system pumps chilled water from the chilling area to the computer room air handler (CRAH) units throughout the entire data center.
Pros to a chilled water system are the high level of reliability and the cost savings to the data center. These systems allow centers to run air conditioning units when power usage is less expensive. During the day, when energy rates are higher, the center can tap into the storage that is cooled and use that rather than requiring the air conditioning system to run full time during the day.
Air Cooled System
Other data centers use air to keep the equipment cool in the center. With these systems, an air conditioner is combined with a condenser. Systems for air-cooling are divided into two pieces. Half the components are located in the computer room air conditioner, and the rest are located in the condenser that is placed outside the facility.
The advantages to using an air-cooled system in a data center are many. Cooling with air is more environmentally friendly, can greatly lower cooling costs, and is proven to be safer than many other cooling options. Energy is saved because air conditioning units don’t have to constantly be running, and can be turned off for intervals in order to preserve energy and save money.
With an air-cooled system, the mechanical designs prevent water from coming through openings in the building, increasing the safety of the cooling system. Air cooling systems also utilize filters to clean air from outside before it enters the building. Many systems for cooling that use air can also be conditioned by using humidification. All these factors work to increase the safety of the cooling system as it cools the computer room and all your important equipment.
Cooling Design Basics
Along with the type of medium that is used to cool the center, each data center design must choose to use room, row, or rack-based cooling to more effectively cool equipment. Depending on how the room is designed, the air will be pushed through in different ways.
Room-Based Cooling
In room-based cooling, a center may employ one of more air conditioners that supply cool air. Dampers, vents, or ducts do not restrict this air. With room-based cooling, the supply and return may also be constrained partially by an overhead return or raised floor system.
With room-based cooling, the design is often constricted by the unique measurements of the room. As more power is used, it may be more difficult to predict performance and maintain uniformity in cooling levels throughout the center.
Row-Based Cooling
In row-based cooling, the air conditioning units are connected to a specific row and are dedicated to this particular row for cooling purposes. This creates paths for airflow that are more clearly defined and shorter distances. This also allows for a much more predictable airflow, allowing the cooling system to achieve a higher power density. Row-based cooling systems are also more efficient due to the reduction in the length of the airflow path.
Rack-Based Cooling
In this type of cooling for data centers, the cooling unit is associated with a particular rack that is holding equipment. Each unit is mounted directly within or to each individual IT rack. With rack-based cooling, the airflow paths are even shorter and better defined than with row-based cooling. Because of this, airflows are not affected by any room constraints or variations in installation. Rack-based cooling allows for the highest power density to be utilized within the cooling system.
Rack-based cooling is also the most efficient, as the airflow paths are the shortest length of all three types of cooling. The cooling specifications can also be designed to the equipment on each rack, rather than for an entire room or row of equipment.
The Importance Of Cooling
Keeping IT equipment cool is an essential part of the design of any data center. With data centers using so much energy, choosing the most efficient cooling system can not only save money, it can also decrease harmful effects to the environment and support your cause for using less energy to run your center.
