Compaq ProLiant BL e-Class System Overview and Planning

Compaq ProLiant BL e-Class System Overview and Planning 30
Appendix A: Input Current and Thermal
Dissipation Calculations
The input power is necessary for determining the input current and thermal dissipation. For a
given input power, the input current varies depending on the input voltage level.
The relationship among the current, the voltage and the power for the power supply input is as
follows:
Input Current = Input Power/Input Voltage
For example:
Input Current = 1000 W /110 V = 09.1 A
Input Current = 1000 W /208 V = 04.8 A
The thermal dissipation can be calculated from the input power as follows:
Thermal Dissipation = Input Power x 3.41
For example:
Thermal Dissipation = 1000 W (input power) × 3.41 = 3410 BTUs/hour
The easiest way to calculate the thermal dissipation for the entire rack is to add the input power
requirements for all the ProLiant BL e-Class server blade enclosures and other units populated in
the rack and multiply the total input power by 3.41. The total thermal dissipation helps you
determine cooling and environmental requirements for the populated rack. Table 3 lists the input
power of each subsystem component.
Table 3. Measured Input Power for Subsystem Components
Subsystem Components Power Input
ProLiant BL e-Class server blade enclosure (without interconnect tray): Base
configuration
50 W
a. RJ-45 Patch Panel (with Integrated Administrator module) 25 W
b. RJ-21 Patch Panel (with Integrated Administrator module) 25 W
c. C-GbE Interconnect Switch (with Integrated Administrator module) 95 W
700-MHz ProLiant BL10e server blade with 128-MB memory
1
40 W
700-MHz ProLiant BL10e server blade with 256-MB memory
1
40 W
700-MHz ProLiant BL10e server blade with 512-MB memory
1, 2
41.6 W
700-MHz ProLiant BL10e server blade with 1-GB memory
1
41.6 W
Note:
1
DIMM input power may vary depending on the component manufacturer. Follow Compaq guidelines for
selecting low-power DIMMS.
2
Server blades ship standard with 512-MB memory.