Backplane Air-Conditioning Technology in data centers

Backplane Air-Conditioning Technology in data centers

In recent years, data centers have developed rapidly towards a large scale, integration, and high energy consumption. According to a survey, the power consumption of servers has increased by 15 times over the past decade. Currently, the power consumption of a single rack is between 20 and 20 ~ 30KW. Network equipment is also growing. Some large network equipment requires several talents to be able to carry up, weighing hundreds of kilograms, and some devices are higher than others. This kind of equipment naturally produces higher heat. These high-performance devices cause a sharp increase in the internal heat of the data center, posing a severe challenge to the data center heat dissipation. As these high-fever devices enter, the temperature in the data center continues to rise, the temperature varies in some regions. To maintain the constant temperature and humidity of the data center, many data center air-conditioning technologies have emerged. Some have started from the energy-saving perspective and some have started from the cost perspective, some have their own advantages in terms of layout structure. This article will explain a new type of data center air-conditioning technology. This technology is very meaningful for lowering the local temperature, and it is also a pain point for directly hitting the data center air-conditioning technology, this is the backplane air conditioning technology.

Backplane air conditioners are composed of cooling coils installed on the back of the data center rack, cooling units providing Cold Sources, and cooling water systems. The working principle of Backplane air conditioners is as follows: the cold air in the IDC room is sucked into the cabinet by the fan of the internal equipment of the cabinet and cooled down the equipment. After receiving heat, the air flows to the cooling coils installed on the back of the Cabinet, heat Exchange is performed between the hot air and the cooling coil to transfer the heat to the refrigerant in the heat exchanger. The cold air after the temperature is reduced is blown out from the backboard to complete the air circulation in the data center. Based on the refrigerant used, backplane air conditioners can be divided into water-cooled backplane and Heat Pipe backplane. The water-cooled backplane uses water as the refrigerant carrying agent, while the water resources are relatively rich. Therefore, the investment is lower. The water-cooled backplane reduces the heat exchange rate and improves the efficiency. However, as the chilled water enters the data center, the risk of the data center becomes higher. Once a water leak occurs, the equipment will be damaged. Most of the equipment in the data center cannot be waterproof. All water pipes connected to the data center must be welded to reduce water risk. The heat pipe backboard uses Freon as the refrigerant carrying agent. The investment is high and the heat exchange rate is increased. The system efficiency is slightly lower. However, the water does not enter the equipment room, and the safety of the equipment room is higher.

Backplane air conditioners are designed with no fan, no power requirements, no energy consumption, and no noise. Dynamic, accurate, and intelligent cooling technology can reduce the cost of cooling energy consumption, efficient and accurate heat exchange reduces the requirements for data centers. Compared with other data center air-conditioning technologies, backplane air-conditioning technology has many advantages. First, the cooling coil of the backplane air conditioner is closer to the heat source, and the temperature of the equipment vent in the cabinet is higher, which provides conditions for greatly increasing the temperature of chilled water supply and return water. The increase of chilled water supply and return water temperature can increase the use time of cooling by external cooling towers, greatly reducing the air conditioning energy consumption in data center equipment rooms and saving energy compared with other air conditioning technologies; second, local hot spots are avoided. Inside and outside the Cabinet is the largest heating area in the data center, and the heat of different equipment is also different, resulting in a great difference in the temperature of different cabinets and the surrounding areas, which leads to uneven local temperature. Backplane air conditioners are installed on the back of each cabinet. One-to-one cooling equipment directly cools down local hot spots to eliminate local hot spots. The third backplane air conditioner occupies a small amount of space and does not require air conditioners. It also removes overhead floors and lowers the floor height, greatly saving the space inside the data center, more business equipment can be placed on the unit area, which will greatly improve the data center utilization. Now, for better cooling effect, the racks are placed face to face and back to form cold and hot channels. In the future, when the data center uses backplane air conditioners, all the channels will become cold channels, and the racks will no longer need to be placed face to face and back to back. They can be placed in sequence, the data center space design is more flexible. At last, the backplane air conditioner is very sensitive to over-cooling and over-heat, and the backplane air conditioner has the ability to automatically adjust the cooling capacity. According to the changes in the heat load of the Cabinet, a balance is achieved between the temperature and the cooling capacity, when the heat is less than the rated refrigerating capacity, the refrigerating capacity can be adjusted by adjusting the water volume.

Of course, any technology has its own limitations, and backplane air conditioners are no exception. Compared with other air-conditioning technologies, backplane air conditioners have unique advantages, but there are still some shortcomings. For example, the backplane air conditioner is too close to the equipment. If a water-cooled backplane is used, a water leakage accident may cause irreparable losses, and a large number of equipment may be damaged, resulting in a high risk factor. If a heat pipe backboard is used, it is also risky. Once a freon leak occurs, it is a toxic gas that can cause damage to people. In addition, backplane air conditioners do not have the humidification function. If backplane air conditioners are deployed, you must configure the relevant equipment in the data center to control the humidity. However, the current air conditioners support both temperature control and humidity control, this will inevitably lead to the purchase of some air conditioning equipment for dehumidification, resulting in a waste of Air Conditioning resources. In addition, backplane air conditioners do not have the backup function. In a data center, multiple air conditioning devices can be deployed to back up the backplane air conditioners. However, backplane air conditioners are difficult to back up redundant data, it needs to be changed immediately. Otherwise, some devices may be down due to overheating. In addition, the cooling coils of Backplane air conditioners are composed of many pipelines, which deploy the backend of the Cabinet at a lower level. They do not look beautiful enough. All the cabinets are placed behind the pipes, which gives a messy feeling, this affects the appearance of data centers. Therefore, in the data center, we should also share the backplane air-conditioning technology with other air-conditioning technologies. Backplane air-conditioners are mainly used to eliminate local hot spots, while other air-conditioners are used to reduce the overall data center temperature, the two can be combined, but this may lead to an increase in the overall air-conditioning costs. The specific deployment depends on the actual situation of the data center.

Although the backplane air-conditioning technology has some shortcomings, it is more advantageous than other air-conditioning technologies. In summary, the backplane air conditioning technology is more advantageous and will be the mainstream direction for the development of air conditioning technology in data centers in the future. If the backplane air conditioning technology can solve the problem of processing the humidity in the IDC environment and improve the air conditioning backup method, it will certainly be widely used in the Air Conditioning Field of data centers.