Juniper SRX5800 Hardware Manual page 189

3. Calculate input power. In this step, the input power requirements for the example configuration are
calculated. To do this, divide the total output requirement by the efficiency of the power supply as
shown in Table 48 on page
NOTE: Normal-capacity AC and DC power supplies are not included in the following
table, because their power budget was exceeded in the sample configuration.
Table 48: Calculating Input Power for SRX5800 Services Gateway with SCB2 and RE2
Power Supply
SRX5800 AC high-capacity
SRX5800 DC high-capacity
1
These values are at full load and nominal voltage.
4. Calculate thermal output (BTUs) for the system. To calculate this value, add the total input power
requirement (in watts) for the two zones together and multiply the sum by 3.41 as shown in
Table 49 on page 190
Table 49: Calculating Thermal Output for SRX5800 Services Gateway with SCB2 and RE2
Power Supply
SRX5800 AC high-capacity
SRX5800 DC high-capacity
190.
Power Supply
1
Efficiency
~88 %
86 %
.
Input Power Requirement
Zone 0: 4040/0.88= 4590 W
Zone 1: 4130/0.88= 4693 W
Zone 0: 4040/0.86= 4697 W
Zone 1: 4130/0.86= 4802 W
Thermal Output (BTUs per hour)
(4590 + 4693) * 3.41 = 31,655 BTU/hr
(4697 + 4802) * 3.41 = 32,452 BTU/hr
190