Selection skills of precision air conditioner and comfort air conditioner

Selection skills of precision air conditioner and comfort air conditioner

When doing intelligent and informatized projects, it is inevitable to do computer room projects. Air-conditioning is inevitable for computer room engineering. Some people will say that the cost of precision air-conditioning is so high. Can small projects be replaced by small-sized ordinary comfortable air-conditioning?

　　So, what is a precision air conditioner in a computer room? Precision air conditioner (also known as constant temperature and humidity air conditioner), the foreign name Precision Air Conditioner, refers to a precision air conditioner dedicated to the computer room that can fully meet the environmental conditions of the computer room. It is a new model that has been gradually developed in the past 30 years. Its characteristics are Large air volume and thermal load changes are used in computer rooms, libraries, archives, banknote printing plants, etc. Precision air conditioners mainly provide year-round uninterrupted cooling, precise humidity control, and higher cooling capacity/square foot than comfort air conditioners.

　　 Generally, 30% of the cooling load of the comfort air conditioner is to eliminate the latent heat load, and 70% is to eliminate the sensible heat load. For the computer room, the situation is quite different. The computer room is mainly the sensible heat emitted by the equipment, the heat load emitted by the indoor staff and the heat and humidity load of the fresh air entering the room in summer (only 5% of the total load) . Comfortable air conditioning systems include ordinary air conditioning, central air conditioning in residential areas, and air conditioning systems in offices and commercial office buildings. They mainly provide a comfortable environment for the staff. There are the following obvious differences between the two:

　　 1. Different applicable environment

　　The computer room is mainly electronic equipment, and the heat density in its environment is 3-5 times that of the general office environment, and it will continue to increase. The design of precision air conditioners is designed to solve the large load heat density in the data center. Precision air conditioners can achieve a higher sensible heat ratio, help maintain the set temperature and humidity level, and can achieve better air filtration through a larger air flow.

　　2, the degree of air filtration is different

　　For the computer room, even a small amount of dust or other particles can damage the storage media and electronic components. Most comfort air conditioners use residential air filters with a filtration efficiency of only 10%, which is far from enough for the data center environment. The filter of the precision air conditioner has a more efficient internal filter cavity, and its efficiency can reach 20%-30%, and it meets the ASHRAE standard.

　　3, the duration of continuous operation is different

　　 Comfortable air conditioners used in most office buildings run on average 8 hours a day, 5 days a week. For precision air conditioners, regardless of the external environment, most data centers require uninterrupted heat dissipation 24 hours a day, 365 days a year. For precision air conditioners, their components are designed to meet high-standard refrigeration requirements, so they can operate continuously.

　　4, different operating conditions

　　 Comfortable air conditioners with outdoor heat exchangers, when the outside ambient temperature drops below 32°F, they generally cannot operate due to low pressure. However, the precision air conditioner can operate normally at -30°F, while the glycol refrigeration system normally cools at -60°F.

　　 5. Different investments

　　 The initial investment of precision air conditioners is basically much higher than that of comfort air conditioners. However, the annual operating cost of comfort air conditioners is higher than that of precision air conditioners by $243 per ton of cooling capacity. This is consistent with the principle generally recognized by the industry, that is, the cooling capacity of a comfort air conditioner with 3 tons is equivalent to the cooling capacity of a precision air conditioner with 2 tons. Therefore, in the case of sufficient funds, it is recommended to consider the initial investment and operating costs.