5. Integration in the overall monitoring procedures of the company, including the out-of-bond management.

6. Implementation of a reporting structure.

To be honest, the simple placement of the racks and systems according to a warm air aisle/cold air aisle concept should really be an obvious step nowadays. But computer centers, especially small ones, which have developed over the course of time are often not yet designed in accordance with this principle. Later modifications originally intended strictly as a stop-gap ­measure often have a disruptive effect on air circulation in the room as well. Of course, measuring the current relationships and climatic conditions in a room and the subsequent 3-D air flow simulation (CFD simulation – computational fluid dynamics) is an extremely complicated task requiring high one-off investments and ultimately providing only a snapshot of the conditions at the moment. Such an expenditure of money and effort is ­rewarding only after a preliminary analysis and inspection of the computer center (motto: “unusual air flow conditions in the aisles”) have been carried out by a specialist and revealed critical points and issues. Common temperature measurement sensors can also indicate whether such a very expensive flow analysis is really required.  The question of direct water cooling at the rack or system versus room air cooling can be reduced for the moment to two major criteria for the decision.

When the cooling requirements per rack reach about eight to ten kW, existing room air cooling systems become inefficient or even overloaded. One solution here is the fitting of cold aisle housings which increase the heat load being carried away to as much as 15 kW. Beyond this, especially for systems with very high waste heat production, e.g., blade or high-density ­systems larger than 15 kW, there is no choice other than direct water cooling at or in the rack. The various manufacturers of rack ­systems today offer flexible installation and expansion solutions which can even be integrated retroactively and without interrupting operations in a computer center.

Despite the possible retrofitting of direct cooling systems, the history of an existing computer center must be considered. It may well be that additional water cooling systems require ­special connections which are not always simple to realize or the ­strengthening of the limited power lines currently ­available – including such security backup components as UPS (UPS: Uninterrupted power supply (usually secured by batteries)) or generators. In such cases, it would be better to postpone the ­integration of a water cooling system until a new facility can be built or the center moves, nor should safety aspects and concerns about water damage be ignored. Naturally, sourcing options of external computer center service providers or strategic ­fundamental considerations about the computer center could play a role here as well. In the meantime, the design of the current room air ­cooling, even if there are other negative aspects such as a worsening of the air flow conditions in the server room, can be improved.