Cooling
Let's start with the story of refrigeration and air conditioning. In the data center, used precision (from Eng. Precision - accuracy) air conditioning, used to operate the traditional scheme of functioning of the "chiller-fan coil" and provide permanent cooling of the server room.
This air conditioning system in which the coolant between the central chiller (chiller) and cooling units (fan coil) is chilled fluid (coolant), circulating at a relatively low pressure.
Also chillers and fan coil units in the system includes a pump station (hydronic), a subsystem of automatic control and pipework between them. The greatest burden falls on the summer season, when the difference between ambient temperature and the temperature inside the server maximum. At other times, the system uses the technology of "free cooling", which uses a low temperature environment for natural cooling with minimal load on the chillers. Such technologies are actively using the largest corporations in their data centers - for example, Microsoft makes the most of them in the data center, located in the cool climate of Ireland (Dublin). Very interesting photo report can be viewed at the link.
The pumping station is an important component of the system. Here are working around the clock pumps that fed continuously flows from the refrigerant chillers to fan coil units.
Redundancy means that for the system need to work at least two pumps. We installed three pumps that work in shifts. Every 10 hours of running the pump off, and instead launched an idle pump.
This ensures even during operation and in case of failure of one of the pumps, it does not affect the operation of the system. System engineers of our data centers during daily rounds sure to check the condition of pumps and control readings of their work. To monitor the health of chillers have derived a separate hardware control panel cooling system, for which the room is being monitored.
We use classic layout configuration server cabinets, forming two climatic zones in the server room. Two rows of struts disposed to the front of each other. Cool air enters from the raised floor, and the servers take it from there. This climate zone is called the "cold corridor". The temperature in this zone is +20 ± 2 ° C.
The air is hot during the operation of servers, is released into the space behind racks where the so-called "hot" corridor. There are fan coils, aspirating hot air for cooling.
Timely information about the temperatures in the "hot" and "cold" enters the corridors around the clock duty system engineer to update interval of 30 seconds.
If the temperature is out of range, an alarm is heard. During rounds engineers measure the temperature of equipment contactless laser thermometers. If we find that the client equipment overheats, we immediately inform the client about this, pointing logged temperature.
