Open racks provide free access and open circulation of air. Images courtesy of Chatsworth Products, Inc.

Once the basic quantity of equipment is identified, the next step is to focus on how it can best be arranged. Typically, computer servers or other hardware are stacked vertically either in open racks or inside enclosed cabinets. Racks provide unrestricted ventilation and air flow and easy, open access to cables and equipment. Due to this open condition, the heat generated by the equipment is released directly to the room and dissipated and treated as part of the room HVAC system. For relatively small systems in a larger building, this may be fairly straightforward to address. In cases where large systems are needed, then it may be more appropriate to consider an enclosed approach that uses cabinets to intentionally restrict and control air flow and ventilation around equipment. While cabinets will obviously cost more than open racks, they allow greater opportunities for security control, as well as the potential to work within a system that can better control cooling needs and the associated costs of energy use for that cooling. Each rack and cabinet will have a rated capacity of pieces of equipment that can be installed that will need to be determined by equipment suppliers. Limiting criteria include not only the size of the actual pieces of computer hardware, but also the required clearances and spacing around them. In the case of the cabinets, the ratings for allowable heat buildup inside the cabinet will also come into play. In some cases, other user restrictions may apply. Nonetheless, through the appropriate collaborative review, the total number of needed racks or cabinets can be determined along with their physical dimensions as individual units and as a group connected together.

Enclosed cabinetry can be an overall cost and energy efficient approach in data center design. Images courtesy of Chatsworth Products, Inc.