At the heart: Server room air conditioning
The server rooms of the data center take up an area of 4,800 m². Of course, the many IT and communication systems need to be cooled. For precision cooling, upright precision air conditioning units for IT operating rooms (STULZ CyberAir 3) were employed. The supply air is cooled in a circulatory process, and is conveyed by the units directly into the raised floor.
To ensure a perfect cooling function and enhance efficiency, hot and cold zones have been structurally separated.
Every precision air conditioning unit features its own controller − all units are connected both to one another and to an external operator terminal via a bus line. Each of these units can be controlled individually. However, they can also be controlled in groups based on room zones, or altogether in a single zone. The type of control is supply air control with exhaust air limitation.
"n+1" principle for chilled water generation and distribution
Chilled water supply and distribution is based on the n+1 principle. In addition, the full chilled water supply continues if a unit fails; the same applies if a unit needs servicing.
To ensure that the complete cooling capacity remains available, the redundant installation of chillers and precision air conditioning cabinets is required. The precision air conditioning cabinets are supplied by an "A" and a "B" rail. Each of these supply rails is capable of covering the entire cooling capacity of a server room. In order to guarantee that both cooling rails are subjected to an identical load, as a general rule a server room is supplied 50% by supply rail A and 50% by supply rail B. The principle of redundancy is evident in all critical plant parts, so that even individual pumps are installed in duplicate. Over and above the "n+1" principle, the chilled water distribution and recooling circuit are designed as a loop, providing additional security for the hydraulic supply.
Server room hybrid recooling system
To increase the energy efficiency of the entire chilling system, this can also operate in Free Cooling mode. High-powered recoolers have been provided and their coils sprayed with osmosis water, enabling the maximum Free Cooling yield from the environment. The water used for this purpose is drawn from a groundwater well, filtered and treated via osmosis. Since a constant cooling capacity and recooling performance can be expected throughout the year, the recooling system is based on 100% water without antifreeze for both recooling and Free Cooling.
The outside air is first cooled adiabatically to wet bulb temperature via a very fine spray mist. Next, the humid, slightly supersaturated air passes through the two heat exchanger stages, where energy is removed in both sensible and latent form. The recooling performance is continuously controlled by means of the regulated fan and humidifier outputs, based on the chilled water outlet temperature of the recooling system.
Temperature control of office area
In general areas heat is emitted by radiators, and a heating/cooling ceiling system is installed in the office area.
The recooling circuit of the server room chilled water system is used as a heat source or heat sink for the offices. The compact unit with integrated multi-stage heat pump for heat and chilled water generation has an integrated redundant chilled water circuit, and provides the required heating energy
