High density data center cooling System

Cooling System: high-density data centers will replace low-density data centers.The theory is that providing higher density can save cost, while saving cost can also bring potential failure risks to the refrigeration system.Now, in the industry, it is generally accepted that the power load of each cabinet is 10kW or above, which is high density (cabinet).

Power density can also be measured by energy consumed per square foot, which is why many high power density data centers are built.As the density of the cabinet increases, data center engineers and their designers must come up with more efficient cooling solutions to offset energy consumption.
The traditional data center design cannot meet the refrigeration requirements of these high-density data centers, which leads to the development of cooling solutions such as CRAC units.Water cooling rack, water cooled back panel and air passage control structure.Unfortunately, adding infrastructure and CRAC (a cool air conditioner) is not enough to meet the cooling needs of the data center.
When the frequency conversion CRAC is running, the energy consumption will increase if the load is reduced.Continuous operation of CRAC is the most traditional and most efficient way to refrigerate.Unfortunately, the cooling system with CRAC refrigeration is not independent and the energy consumption is high. Besides, it is necessary to run several CRAC systems at the same time to meet the needs of refrigeration, so the operation cost is higher.Water-cooled lagging and airflow containment channel structure are the most popular and efficient cooling solutions at present, which will not consume too much energy.
Effective management of airflow tissues is a successful solution that can prevent data centers from overheating and reduce operating costs.Water cooled backboard adopts liquid refrigeration technology to exchange cold and hot air.The cold water in the closed loop of the back door cooling unit can counteract the heat generated by the high - density frame.
It can improve the efficiency of refrigeration by using freezing water or cooling water at low temperature.This is done in order to ensure the cooling and to make up for the dehumidification.This kind of system, it is best to design at the beginning of the design center, do not design the high floor activity floor, the way that the cable is laid out does not use the way to walk the line is regarded as the most suitable for the use of water cold back board.
The channel containment structure is a precast system that combines the channel containment design of the independent device.
Because the airflow channel containment system can improve the minimum inlet air temperature of the cabinet, the cold/hot channel air flow containment system can improve the efficiency of the traditional refrigeration system of the data center.
Because of low fan speed, higher freezing water temperature and natural cooling, a higher temperature data center can save more energy.The heat (cold) channel containment structure minimizes the mixing of cold and hot air flow.This, in turn, increases the capacity and efficiency of the refrigeration infrastructure.
(note: free cooling: natural cooling (1) direct natural cooling is to connect the cooling water and the freezing water system through the bypass system, directly connecting the cooling tower and the terminal equipment.When outdoor wet-bulb temperature is about 5 ℃ lower than chilled water, you can switch to run this way.Because this method is the cooling water system and freezing water system directly connected, easy to clean cooling water road cooling water pollution, easy to cause the pipeline corrosion, and blockage of the coil, so it is difficult to achieve in open type cooling tower system, general suitable for closed cooling tower systems.
(2) the indirect natural cooling, namely to add a plate heat exchanger in the system and condenser in parallel, when the wet bulb temperature is lower than outdoor temperature is about 5 ℃, frozen water from the freezer to switch to the heat exchanger.Because indirect natural cooling USES plate heat exchanger to isolate the freezing water and cooling water system, it does not cause pollution to the frozen water pipeline, so the open and closed cooling towers are applicable.At present, this method is more used in engineering.
Natural cooling is another system for high power density data centers.A temperature of 86 degrees Fahrenheit (30 degrees Celsius) in the data center can be done by outside air cooling, if the data center air temperature in a 77 degrees f (below 25 degrees Celsius), does not require additional mechanical refrigeration.The downside of this approach is that dust can get into the data center with the external air.
Using the Kyoto wheel (rolling heat exchanger) as a filter to better improve the problem.It consists of a metal wheel rotating through two parts of space.When cold air passes through the second part, the hot air of the center flows through a space.When the hot air flows through a space, the heat is transferred to the metal in the wheel, and the air flows back to the data center, while the external air absorbs heat from the metal.
(note: Kyotocooling: founded in 2006, the company is the most experienced supplier of indirect cooling solutions for the data center industry.The company has offices in amersford and Holland;Dallas, Texas;In Johannesburg, South Africa and tianjin, China has established authorized proxies in North America and Australia.
Kyoto wheel: rolling heat exchanger, which contains 98 percent of the open aluminum media, which transfers the air flow from one side to the other like the flute.KyotoCooling USES external air as a cooling source for the data center when the external temperature is lower than the inlet temperature requirement of the data center.Heat is transferred to the outer air as the wheel rotates.The efficiency of transmission is very high.Isolation measures (cold and hot channels or chimneys) are fully supported, and the system can also be used for traditional non-segregated designs.
The purpose of the closed cold channel is to ensure that cold air enters the server from the front of the cabinet as far as possible, and the hot wind returns to the precision air conditioner through the return air channel.It includes the installation of a channel ceiling, a closed door at either end of the channel or an elevated upright wall system, which can be redirected to the server's air inlet and to prevent the hot wind from recirculating.Cold channel containment is also highly efficient.
The cold channel containment structure ensures that IT equipment runs under rated condition.Cold channel containment structure can eliminate hot spots and improve operation efficiency.As a result, the entire data center will have more available space.
Thermal channels is around the server rack inside the heat emissions, its role and cold channel, is to prevent the mixture of cold and hot air, but the thermal channel in the face of air conditioning ducts, the heat flow as the return piping back to the air conditioning, and out of air supply outlet.
To do so, it is necessary to provide a method to air the air return air temperature setting value.In some cases, the hot return air temperature is the highest, which can double the refrigerating capacity.Thermal channel containment can double the cooling capacity of CRAC units, thus reducing costs and improving efficiency.
With the explosive growth of digital demand in data center industry, high-density data center will become more and more popular.At present, data center operation and management personnel should be responsible for reducing energy consumption and improving efficiency.Having a high power density data center can improve performance and yield, and build efficient cooling systems to reduce energy consumption.