Application and energy saving of plate heat exchanger in data center
1, water cooling system
From 2005 to 2009, the Internet industry developed rapidly, and the demand for data services soared. Data centers with small scale and low power density had to bear a lot of IT equipment. At this time, the power density of the single cabinet has increased to 3~5kw, and the size of the data center has gradually increased. Medium-sized data centers with hundreds to thousands of cabinets have begun to appear. As the scale has grown, data center energy consumption has increased dramatically, and energy conservation issues have begun to receive attention.
The traditional air-cooled direct expansion system has lower energy efficiency than COP (Coefficient Of Performance). The COP in Beijing is about 2.5~3.0. The air-conditioning equipment consumes a lot of power and accounts for a high proportion of the overall power consumption of the data center. Moreover, with the expansion of installed capacity, the installation position of the air-cooled condenser reserved in the original data center building is seriously insufficient, and the noise disturbance problem is prominent, which restricts the expansion of the data center. At this time, the chilled water system widely used in office buildings began to be gradually applied to the data center refrigeration system. Since the COP of the chiller can reach 3.0~6.0, the large centrifugal chiller is even higher, and the chilled water system can greatly reduce the data. The center operates energy consumption.
The chilled water system is mainly composed of a chiller, a cooling tower, a chilled water pump, a cooling water pump, and a chilled water type air conditioner end. The system adopts centralized cold source, the cooling efficiency of the chiller is high, and the cooling tower is placed in a flexible position, which can effectively control the noise and benefit the aesthetic appearance of the building. After reaching a certain scale, it has more construction cost and maintenance cost than the direct evaporative system. Economic advantage.
The end of the air-conditioning system used in the chilled water system is a chilled water-type precision air conditioner, and its single cooling capacity can reach more than 150kw. The air supply mode and the previous air-cooled direct expansion system have not changed much, only the cooling medium in the end changes. The air conditioning equipment is still far away from the IT heat source, and mainly relies on the air-conditioning fan to deliver air to maintain the airflow organization.
2, plate heat exchanger and water cooling system natural cooling
From 2010 to the present, with the development of data center cooling technology and people's further attention and pursuit of data center energy consumption, the concept of natural cooling has gradually been applied to the data center.
In the northern part of China, the outdoor temperature is lower in winter, and the water side natural cooling system is used. In winter, there is no need to open the mechanical refrigeration unit, and the cooling tower and the plate heat exchanger are used to “free” to obtain the cold source, thereby reducing the energy consumption of the data center. The water side natural cooling system is a set of plate heat exchangers and related switching valve groups above the original chilled water system. The chiller mechanical cooling is still used in high temperature weather, and the low temperature cooling water prepared by the cooling tower is used in the low temperature season. The high-temperature chilled water is exchanged for heat. In the transitional season, the lower-temperature cooling water and the higher-temperature chilled water are pre-cooled before entering the chiller, and the chiller load and running time can be reduced.
Principle of natural cooling system for water cooling system
The temperature of chilled water in traditional data centers is generally 7/12 °C. For example, in Beijing, natural cooling can be used 39% of the year. If the chilled water is raised to 10/15 °C, the natural cooling time will be extended to 46%. At the same time, due to the increase of evaporation temperature, the COP of the chiller can be increased by 10%. On the other hand, as the server withstands the increase in temperature, the chilled water temperature can be further increased, and the natural cooling time throughout the year will be further extended. At present, the domestic technology-leading data center has increased the chilled water temperature to 15/21 °C, and the natural cooling time can reach 70% or even longer.