Data centers need cooling systems to prevent the sensitive electronic equipment they contain from overheating. Data centers typically have a high concentration of electrical and electronic equipment, which generates a significant amount of heat. If this heat is not properly managed, it can cause the equipment to malfunction or even fail.
Cooling systems in data centers help to regulate the temperature and maintain it at an optimal level. This ensures that the equipment can operate at its best and helps to prevent overheating and damage. Cooling systems can also help to extend the lifespan of the equipment, reducing the need for costly repairs and replacements.
Data Center Cooling Technologies
Liquid cooling and air cooling are two common methods used in data centers to remove heat generated by the servers and other equipment. Air cooling uses fans to blow air over the hot components in the data center, which cools them down. This is a simple and inexpensive way to cool a data center, and it is often used in smaller facilities. Liquid cooling, on the other hand, involves circulating a liquid coolant through the data center to remove heat from the equipment.
Liquid Cooling
Liquid cooling involves circulating a liquid coolant through the data center to remove heat from the equipment. This is done by placing the hot components in direct contact with the liquid coolant, which absorbs the heat and carries it away from the equipment. The major types of liquid cooling in data centers are immersion, rear-door heat exchangers, and direct-to-chip.
Immersion Cooling
In immersion cooling, servers and other equipment are placed inside a tank filled with the liquid coolant. The coolant is circulated through the tank by pumps, and it comes into direct contact with the hot components, removing the heat from them. The cooled liquid is then circulated back through the system to continue removing heat. However, it requires specialized equipment and careful maintenance to ensure that the liquid coolant does not leak or cause damage to the equipment.
Rear-Door Heat Exchangers
It is called a “rear-door” heat exchanger because it is typically installed on the back of the server racks in the data center. The RDHX uses a heat exchange mechanism to transfer heat from the hot components in the server racks to a coolant, such as water or a specialized fluid. The coolant absorbs the heat and carries it away from the equipment, where it can be dissipated by a cooling system.
Direct-to-Chip Liquid Cooling
Direct-to-chip liquid cooling, also known as chip-level cooling, is a method of removing heat from the processors in a data center. It involves circulating a liquid coolant directly to the surface of the processors, where it absorbs the heat and carries it away from the chip. It is typically used in conjunction with other cooling methods, such as air conditioning, to provide a more effective cooling solution for the data center.
Air Cooling
Air cooling is a more traditional method of cooling data centers in which the heat generated by the servers is transferred to the air, which is then cooled using air conditioning units. This method is generally less efficient than liquid cooling, as air is a poor conductor of heat compared to a liquid. However, it is also less expensive and simpler to implement, making it the more common choice for many data centers. The main methods of air cooling in data centers are computer room air conditioning (CRAC), computer room air handler, hot-cold air row design, calibrated vector cooling (CVC), and evaporative cooling.
Computer Room Air Condition (CRAC)
A Computer Room Air Conditioner (CRAC) unit is a type of air conditioning equipment that is used in data centers to regulate the temperature and air quality. Typically installed in the floor of the facility, a CRAC unit works by drawing in air from the data center and passing it through a series of filters to remove dust and other contaminants. The air is then cooled by a refrigerant, and it is blown back into the data center to keep the equipment at the desired temperature.
Computer Room Air Handler (CRAH)
A CRAH unit is similar to a CRAC unit, but it is designed to be installed in the ceiling or on the roof of the data center, rather than on the floor.This allows CRAH units to take up less space in the data center and to be more easily integrated with other cooling equipment, such as rear-door heat exchangers or liquid cooling systems. Overall, the choice between a CRAC unit and a CRAH unit in a data center depends on factors such as the available space, the cooling requirements, and the desired level of flexibility and integration with other cooling equipment.
Hot-Cold Air Row Design
The hot-cold air row design is based on the principle that hot air rises, and that separating the hot and cold air paths can improve the efficiency of the cooling system. In a hot-cold air row design, the servers are arranged in rows, with the front of the servers facing the cold air supply and the back of the servers facing the hot air exhaust.
The hot air from the servers is directed to the back of the data center, where it is drawn into the hot air return plenum by fans. The cooled air is then supplied to the front of the servers through the cold air supply plenum.
Calibrated Vector Cooling (CVC)
Calibrated vector cooling systems are normally implemented in blade server systems with a high number of processors in a small enclosure. Being such a dense system, it produces a lot of heat for such a small area. CVC works by passing cool air into hot, targeted areas within the system. This simplifies the system and allows for less internal cooling fans.
Evaporative Cooling
Evaporative cooling is a method of removing heat from the air in a data center by evaporating water into it. In this process, water is sprayed into the air in the data center, and as it evaporates, it absorbs heat from the surrounding air. This cooled air is then circulated back into the data center to keep the equipment at the desired temperature. Evaporative cooling is a simple and inexpensive way to cool a data center, and it can be an effective method in dry or arid climates where the air has a low relative humidity.
Overall, cooling systems are an essential part of data center design and operation. They help to prevent equipment failure and maintain optimal operating conditions, while also improving energy efficiency and reducing operating costs.
