Calculating System Thermal Output - Juniper PTX5000 Hardware Manual

PTX5000 Packet Transport Router Hardware Guide

Calculating System Thermal Output

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The examples below show the power requirement calculations for different types of
configurations:
NOTE: All the examples below use RE-PTX-X8-64G Routing Engines,
CB2-PTX Control Boards, FAN3-PTX-H horizontal fan trays, and SIB3-PTX5K
SIBs.
This example shows the calculation for a non-redundant base configuration with no
FPCs or PICs at 25° C (77° F) ambient temperature:
1 host subsystem + 1 vertical fan tray + 2 horizontal fan trays + SIBs = output power in
watts
182 W + 80 W + 2(330 W) + 1170 W = 2092 W
Output power in watts / power supply efficiency = power consumption in watts
2092 W / 0.9 = 2324.4 W
This example shows the calculation for a redundant base configuration with four
FPC3-PTX-U3 FPCs and eight P3-15-U-QSFP28 PICs at 25° C (77° F) ambient
temperature:
2 host subsystems + 1 vertical fan tray + 2 horizontal fan trays + SIBs + 4 FPC3-PTX-U3
FPCs + 8 P3-15-U-QSFP28 PICs = output power in watts
2(182 W) + 80 W + 2(330 W) + 1170 W + 4(754 W) + 8(119 W) = 6242 W
Output power in watts / power supply efficiency = power consumption in watts
6242 W / 0.9 = 6935.6 W
This example shows the calculation for a redundant base configuration with eight
FPC3-PTX-U3 FPCs and sixteen P3-15-U-QSFP28 PICs at 40° C (104° F) ambient
temperature:
2 host subsystems + 1 vertical fan tray + 2 horizontal fan trays + SIBs + 8 FPC3-PTX-U3
FPCs + 16 P3-15-U-QSFP28 PICs = output power in watts
2(187 W) + 370 W + 2(900 W) + 1170 W + 8(777 W) + 16(123 W) = 11898 W
Output power in watts / power supply efficiency = power consumption in watts
11898 W / 0.9 = 13,220 W
After you have calculated the power consumption for your configuration, you can use
that information to determine the system thermal output (BTUs per hour). To do so,
multiply the power consumption in watts by 3.41.
For example, above we calculated the power consumption for a redundant base
configuration with eight FPC3-PTX-U3 FPCs and sixteen P3-15-U-QSFP28 PICs at 40°
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