User Service Guide, Fourth Edition - Server Expansion Unit

Chapter 2

Site Preparation

Environmental Specifications

PCI/Mass Storage Section Cooling

Six 92-mm fans located between the mass storage devices and the PCI card cage provide airflow through

these devices. The PCI fans are powered off of housekeeping power and run at full speed at all times. The air

is pulled through the mass storage devices and pushed through the PCI card cage. Perforation is provided

between the PCI bulkheads to allow adequate exhaust ventilation and to help reduce the localized airflow

dead spots that typically occur at the faceplate tail of each PCI card.

Standby Cooling

Several components within the chassis consume significant amounts of power while the system is in standby

mode. The system fans are run at a portion of full speed during standby to remove the resulting heat from the

cabinet. The fans within the power supply operate at full speed during standby.

Typical Power Dissipation and Cooling

Table 2-6 provides calculations for configurations exactly as described in the table.

The air conditioning data in Table 2-6 is derived using the following equations:

• Watts x (0.860) = kcal/hour

• Watts x (3.414) = Btu/hour

• BTU/hour divided by 12,000 = tons of refrigeration required

NOTE When determining power requirements, you must consider any peripheral equipment that will

be installed during initial installation or as a later update. Refer to the applicable

documentation for such devices to determine the power and air-conditioning that is required to

support these devices.

Table 2-6 Typical Server Expansion Unit Power Dissipation and Cooling

PCI Cards

(Maximum 25W)

DVDs

Hard

Disk

Drives

Core

I/O

Bulk

Power

Supplies

Typical

Power

Typical

Cooling

Qty Qty Qty Qty Qty Watts BTUs/Hour

16 1 4 2 2 662 2259

8 1 2 2 2 532 1816

8 0 1 1 2 454 1550