Air flow isolation in the data center. Typical scenarios
Specialists in data center engineering systems do not have long to explain the benefits of isolating the air flow in the server rooms. It allows you to significantly improve the efficiency of the cooling system as a whole, by optimizing the temperature and air exchange, improve the reliability of the IT equipment, by eliminating local overheating zones, increase the energy density of the racks, etc. The result is a more rational use of expensive resources: usable space, electricity, cooling system, with consequent cost savings. The latter is achieved by reducing energy consumption, the possibility of reducing the number of cooling blocks, extending the time of using the free cooling mode (free cooling).
However, even experienced specialists are often confused in the choice of methods and schemes for such isolation. One of the main questions, which is better to isolate: the flow of cooled or exhaust (hot) air? And why does it not make much sense to isolate both? At once, in most cases, isolation of both streams does not provide significant advantages - as an exception, we can give an example of placing IT cabinets in an aggressive environment (say, in production), when insulation is required for both hot and cold streams. But in most data centers, it is enough to isolate only the distribution of hot or cold air.
The question is, after all, to isolate - a cold or hot stream - and at what level - a separate rack, a whole row (corridor) or other space? The choice of a particular option depends on many factors. Here are some of them:
It is clear that to take into account all these factors can only know all the details of the object. However, below we will try to sort out some of the most typical situations.
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In the perimeter cooling systems, air conditioners working on the entire machine room are used, which are installed along its perimeter. If there is a raised floor of sufficient height, cold air is supplied under the raised floor and is output to the IT equipment through perforated tiles. When installing IT racks with the formation of cold and hot corridors, you can isolate the cold corridor, turning the rest of the room into a huge reservoir of spent (hot) air.
An example of the isolation of the cold corridor. The Schneider Electric EcoAisle air containerization system is shown.
This is a highly effective solution, which, however, has a number of limitations. Since the entire room outside the isolated corridors turns into a hot air reservoir, there may be problems with cooling stand-alone IT devices of non-standard dimensions (for example, data storage systems). These problems, of course, can be solved, for example, by installing additional perforated tiles and individual insulation systems for such devices, but this will increase the cost of the project. In addition, because of the high temperature complicates the work of the staff for a long time.
This scheme can be used both in the presence of a raised floor and in its absence. But this requires a duct system or false ceiling, forming a space for removal of the exhaust (hot) air back to the air conditioners. In this case, most of the room turns into a huge reservoir of air-conditioned (cold) air, which simplifies the provision of the necessary temperature conditions for a stand-alone, oversized IT equipment.
An example of insulation of a hot corridor with an air duct, which discharges exhaust air into the ceiling space. The Schneider Electric EcoAisle air containerization system is shown.
Row-down cooling systems, including the installation of air conditioners directly in a row of racks, are becoming increasingly popular due to their high efficiency and the possibility of significantly increasing the energy density of the load. This is due to the fact that the sources of cooled air are located in close proximity to the IT equipment.
When using in-line cooling systems, both insulation options are possible: cold or hot corridors. They are similar to the above schemes for perimeter systems. When isolating corridors, zones consisting of two rows of cabinets are formed, which are united by a common cooling infrastructure. One of the possible problems for the implementation of such schemes is the lack of space in the places of installation of IT racks, which may not allow installing air-conditioners between the racks.
Example of insulation of a cold corridor with in-line air conditioners
This option may be required if there are separate racks of high energy density (more than 6 kW), impossibility of grouping cabinets with IT equipment with the release of cold / hot corridors or in the presence of obstacles (for example, supporting columns) for the installation of a corridor insulation system.
In this case, it is possible to isolate the exhaust air: the air duct is mounted on the cabinet and removes the hot air behind the false ceiling.
An example of the use of individual rack ducts exhaust air. Schneider Electric Vertical Exhaust Duct System Shown
If the energy density requirements are even higher, then you can install a rack with its own cooling unit by implementing air circulation inside the sealed volume.
Example of isolation of air flow at the level of a separate rack
Until recently, one of the major problems with the use of hot / cold corridor insulation systems on the market has been the restriction on the size of the cabinets they combine. Often it was necessary to install similar cabinets of the same width and height. In the summer of 2017, Schneider Electric introduced the new HyperPOD solution to the market, removing most of the restrictions and significantly reducing the labor costs for installing and operating the infrastructure of the data center server rooms.
HyperPOD modules are easily integrated with various types of power distribution, fire suppression and cooling systems. They can be equipped with additional tiers of cable trays, monitoring systems, indoor lighting, video surveillance and access control
The HyperPOD system is based on a self-supporting modular design that is easy to install and allows you to install elements of engineering infrastructure before installing rack-mount equipment. In addition, this solution makes it easy to install or move cabinets during operation. The design of HyperPOD does not impose special requirements for the installed equipment and is compatible with cabinets of arbitrary width and height up to 52U. The solution supports multi-module configurations, which provides the possibility of expansion in increments of 8–12 racks (4–6 in each row).
So, modern means of isolation of air flow can significantly improve the efficiency of the cooling system of IT equipment and the reliability of its work. The choice of the optimal insulation scheme is determined by the specifics of a specific project, but new generation solutions, such as HyperPOD, are quite versatile, easily adapt to almost any situation and help optimize cooling costs.
However, even experienced specialists are often confused in the choice of methods and schemes for such isolation. One of the main questions, which is better to isolate: the flow of cooled or exhaust (hot) air? And why does it not make much sense to isolate both? At once, in most cases, isolation of both streams does not provide significant advantages - as an exception, we can give an example of placing IT cabinets in an aggressive environment (say, in production), when insulation is required for both hot and cold streams. But in most data centers, it is enough to isolate only the distribution of hot or cold air.
The question is, after all, to isolate - a cold or hot stream - and at what level - a separate rack, a whole row (corridor) or other space? The choice of a particular option depends on many factors. Here are some of them:
- The layout of IT equipment. Is the formation of hot and cold corridors? Is the equipment of non-standard overall dimensions?
- Type of cooling system. Perimeter, in-line air conditioners or external cooling system?
- Ceiling height. Is it sufficient to organize a false ceiling and / or insulation of the exhaust air in the false ceiling space?
- The presence and height of the raised floor. When using a raised floor to supply cold air, will its height ensure the supply and distribution of the required volume?
- The location of the columns. Support columns can make installation of insulating panels much more difficult.
- Cable routing. Thick bundles of cables below, under the raised floor, can interfere with the supply of cold air, and above, above the racks, the installation of panels or ducts of the insulation system of the hot corridor.
- The organization of the fire alarm system and fire extinguishing. Insulation can lead to the formation of more powerful air currents, the smoke in which dissipates very quickly, making it difficult to detect fires. In addition, isolation systems can be an obstacle to the spreading agent for quenching.
It is clear that to take into account all these factors can only know all the details of the object. However, below we will try to sort out some of the most typical situations.
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Perimeter cooling systems. Isolation of cold corridors
In the perimeter cooling systems, air conditioners working on the entire machine room are used, which are installed along its perimeter. If there is a raised floor of sufficient height, cold air is supplied under the raised floor and is output to the IT equipment through perforated tiles. When installing IT racks with the formation of cold and hot corridors, you can isolate the cold corridor, turning the rest of the room into a huge reservoir of spent (hot) air.
An example of the isolation of the cold corridor. The Schneider Electric EcoAisle air containerization system is shown.
This is a highly effective solution, which, however, has a number of limitations. Since the entire room outside the isolated corridors turns into a hot air reservoir, there may be problems with cooling stand-alone IT devices of non-standard dimensions (for example, data storage systems). These problems, of course, can be solved, for example, by installing additional perforated tiles and individual insulation systems for such devices, but this will increase the cost of the project. In addition, because of the high temperature complicates the work of the staff for a long time.
Perimeter cooling systems. Isolation of hot corridors
This scheme can be used both in the presence of a raised floor and in its absence. But this requires a duct system or false ceiling, forming a space for removal of the exhaust (hot) air back to the air conditioners. In this case, most of the room turns into a huge reservoir of air-conditioned (cold) air, which simplifies the provision of the necessary temperature conditions for a stand-alone, oversized IT equipment.
An example of insulation of a hot corridor with an air duct, which discharges exhaust air into the ceiling space. The Schneider Electric EcoAisle air containerization system is shown.
Insulation when using row cooling systems
Row-down cooling systems, including the installation of air conditioners directly in a row of racks, are becoming increasingly popular due to their high efficiency and the possibility of significantly increasing the energy density of the load. This is due to the fact that the sources of cooled air are located in close proximity to the IT equipment.
When using in-line cooling systems, both insulation options are possible: cold or hot corridors. They are similar to the above schemes for perimeter systems. When isolating corridors, zones consisting of two rows of cabinets are formed, which are united by a common cooling infrastructure. One of the possible problems for the implementation of such schemes is the lack of space in the places of installation of IT racks, which may not allow installing air-conditioners between the racks.
Example of insulation of a cold corridor with in-line air conditioners
Isolation within one rack
This option may be required if there are separate racks of high energy density (more than 6 kW), impossibility of grouping cabinets with IT equipment with the release of cold / hot corridors or in the presence of obstacles (for example, supporting columns) for the installation of a corridor insulation system.
In this case, it is possible to isolate the exhaust air: the air duct is mounted on the cabinet and removes the hot air behind the false ceiling.
An example of the use of individual rack ducts exhaust air. Schneider Electric Vertical Exhaust Duct System Shown
If the energy density requirements are even higher, then you can install a rack with its own cooling unit by implementing air circulation inside the sealed volume.
Example of isolation of air flow at the level of a separate rack
HyperPOD Solution
Until recently, one of the major problems with the use of hot / cold corridor insulation systems on the market has been the restriction on the size of the cabinets they combine. Often it was necessary to install similar cabinets of the same width and height. In the summer of 2017, Schneider Electric introduced the new HyperPOD solution to the market, removing most of the restrictions and significantly reducing the labor costs for installing and operating the infrastructure of the data center server rooms.
HyperPOD modules are easily integrated with various types of power distribution, fire suppression and cooling systems. They can be equipped with additional tiers of cable trays, monitoring systems, indoor lighting, video surveillance and access control
The HyperPOD system is based on a self-supporting modular design that is easy to install and allows you to install elements of engineering infrastructure before installing rack-mount equipment. In addition, this solution makes it easy to install or move cabinets during operation. The design of HyperPOD does not impose special requirements for the installed equipment and is compatible with cabinets of arbitrary width and height up to 52U. The solution supports multi-module configurations, which provides the possibility of expansion in increments of 8–12 racks (4–6 in each row).
So, modern means of isolation of air flow can significantly improve the efficiency of the cooling system of IT equipment and the reliability of its work. The choice of the optimal insulation scheme is determined by the specifics of a specific project, but new generation solutions, such as HyperPOD, are quite versatile, easily adapt to almost any situation and help optimize cooling costs.
Source: https://habr.com/ru/post/338016/
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