Design and planning Chief Engineer Sun Changqing modern data center network
In Uptime Tier grade standards, Tier IV (fault-tolerant site infrastructure) standard clearly defines the continuous cooling requirements, generally accomplished by setting the thermal storage tank. Of course, cooling may also be achieved continuously provided by way of uninterruptible power supply systems cold source, the cold source so long as to ensure no interruption of power is interrupted. Thermal storage tank only way is the most economical and reliable way, so, in reality, a continuous way more than the main refrigeration in the form of thermal storage tank.
With the development of the data center, for the current domestic level reached TierIII and above the engine room, now generally equipped with thermal storage systems in order to achieve the purpose of safe and reliable cooling system. As to the form of thermal storage tank, but also a wide range, water storage, ice storage case has embodiment, wherein the plurality of water-based cool storage. The use of ice storage case is rare, the use of ice storage system for the use of multi-zone ice storage is the major consideration.
Data in this chapter discuss water storage systems, open and closed water storage system, are the two main forms of thermal storage tank, and the use of open or closed thermal storage tank, affected by many factors, such as building height, such as parks arrangement of cases, such as in the form of air conditioning systems, such as indoor space conditions and so on.
First, look at the basic concepts of open and closed thermal storage tank:
Water storage tank liquid level open to atmosphere, a non-pressure accumulator tank, equipped with water distribution means, the dispensing device to ensure adequate internal plane, the vertical plane in slow flow, Re number less than 800. When the thermal storage tank above the liquid level in the building, thermal storage tank must be configured to open the plate heat exchanger.
Liquid water storage tank is not closed to the atmosphere, the tank is a pressure accumulator, generally circular tank, may supply the cold thermal storage tank directly to the terminal.
Now air conditioning water cooling system piping arrangement used in medium to large data center, there are two main systems, one is a form of a pump system, the second one is the form of a pump system. Both systems form in the data center design, in the end is to choose open or closed choose what form of air conditioning system is the best match? Will once advantages and disadvantages of two forms of air conditioning water system pumps and secondary pumps in closed and open draw a comparison of the following, and then determine which method is more appropriate in the end.
1, a water pump air conditioning system
For primary pump air conditioning system, in order to realize low temperature cold accumulating tank is water, it shall be provided after the cooler, as shown, this is the case, the pressure tank should regenerator point pressure plus the constant pressure cycle pump head, the pressure points is constant pressure elevation chilled water system (typically the height of the building) and to consider a certain margin, a system circulating pump head of the pump to reach 40m or more generally, the thermal storage tank to direct access in the form of access systems, thermal storage tank height need to open higher building height of nearly 40m, may not realize the reality, thus, can only choose a closed thermal storage tank.
To select open thermal storage tank, a heat exchanger must be provided between the thermal storage tank and the chilled water system, so that thermal storage tank and spaced from the chilled water system. Thus, the thermal storage tank open height will not be limited. However, whereby the temperature difference will result between the thermal storage tank with chilled water, chilled water temperature will result in higher than normal operating temperature during thermal storage tank to cool, the data center does not satisfy the requirements of stable operation. Therefore, in the data center, the air conditioning system of the primary pump, thermal storage tank thermal storage tank can only be closed manner access system.
2, secondary pump air conditioning system
For air conditioning water system secondary pumps, thermal storage tank access mode, it may be open or may be closed, because the secondary pump system thermal storage tank, connected to the balance pipe, the pipe is to balance the role of the primary pump equilibrium between the secondary pump flow rate, and to ensure a constant flow of the evaporator, which pressure differential across the very small, generally constant pressure open system is provided on the balancing pipe.
Thus, when the thermal storage tank using open, can be directly used as a pressure tank, which system is higher than the highest liquid level to about 1.5m, the height of the building in the data center data center is not very high, the use of this embodiment purpose, to provide continuous refrigeration can also stabilize the system, but also save indoor floor space, the system is very good form.
In a data center building height is high, the thermal storage tank open height to diameter ratio is too large, relatively poor structural stability, the open had to give up the thermal storage tank programs, in favor of closed thermal storage tank, closed regenerator can be directly connected in series into the balancing pipe, as part of the equalization tube, usually can be slowly filled cold, the regenerator temperature reaches the set value remains completely switched so that no intervention was naturally cooled electricity interruption, safe, reliable and efficient.
Therefore, in the data center, the secondary pump air conditioning system, thermal storage tank thermal storage tank may be a closed system access manner, thermal storage tank may be open access system manner.