Features of Precision Air Conditioner
High sensible heat
Computing equipment such as hosts, peripherals, servers, switches, optical terminals, and power support devices installed in the data center will emit heat to the room through conduction, convection, and radiation. This heat only causes the room temperature to rise, which is called sensible heat. The heat dissipation of a server cabinet ranges from several thousand watts to tens of thousands of watts per hour, and the heat dissipation of blade servers is even higher. The heat dissipation of large and medium-sized computer room equipment is around 400W/m2, and data centers with high equipment densities may reach over 600W/m2. The sensible heat ratio in the data center can be as high as 95%.
Low latent heat
This part of the heat does not change the temperature in the data center but only changes the moisture content of the air inside. This part of the heat is called latent heat. The latent heat in the data center comes mainly from the staff and outdoor air since there are no humidification devices in the room. Large and medium-sized computer rooms generally adopt a management model of separating people and machines, and the enclosure structure of the data center is well sealed. The fresh air generally enters the data center after temperature and humidity pre-treatment. Therefore, the latent heat in the data center is relatively small.
Large air volume and small enthalpy difference
The equipment's heat is transmitted to the data center through conduction and radiation, and the densely populated areas in the equipment generate concentrated heat. To ensure uniform temperature and humidity in the data center and control it within the allowable range, it is necessary to have a large air volume to carry away the excess heat. In addition, there is relatively little latent heat in the data center, so dehumidification is generally not required. The air does not need to be cooled to below freezing when passing through the air conditioner's evaporator, so the temperature and enthalpy differences of the air supply are small.
Continuous operation and year-round cooling
The equipment in the data center generates heat steadily, running continuously throughout the year, requiring an uninterrupted air conditioning system. There are also high requirements for the power supply of the air conditioning equipment, which not only needs dual mains power supply but also requires a backup power generator for the air conditioning system that safeguards important computer equipment. A long-term steady heat source causes the need for cooling even in winter in the data center, especially in the southern region. In the northern region, if cooling is still required in winter, when selecting air conditioning units, the condensation pressure and other related issues should be considered. Additionally, increasing the proportion of outdoor cold air intake can achieve energy-saving purposes.
Multiple return air delivery methods
The air supply method in the air-conditioned room depends on the heat source and distribution characteristics in the room. Considering the characteristics of dense equipment layout, many cables and bridges, and wiring methods in the computer room, the air supply methods of air conditioning are divided into downflow-return, upflow-return, upflow-side return, and side supply-side return.
Air supply through static pressure box
The return air in the data center air conditioning system usually does not use pipes. Instead, the space below the raised floor or above the ceiling is used as a static pressure box to supply the return air. The stable pressure layer formed inside the static pressure box ensures even air supply, making the static pressure at each point in the space equal.
High cleanliness requirements
Electronic computer rooms have strict requirements for air cleanliness. Dust, corrosive gases, and other impurities in the air can seriously damage the life of electronic components, causing poor contact and short circuits. Therefore, specialized air conditioning systems in the data center must be able to filter the circulating air according to relevant standards.