Thermal And Acoustics; Table 17. Power Supply Efficiency; Figure 8. 750W Power Supply Unit - Dell PowerEdge R820 Technical Manual

Figure 8 shows a 750W power supply unit extended from the R820 chassis.
The PowerEdge R820 supports up to two AC-DC or DC-DC power supplies with 1 + 1 redundancy,
auto-sensing and auto-switching capability.
Dell PSUs have achieved Platinum and Titanium efficiency levels as shown in Table 17.
Form factor Output
750W AC
750W AC
Redundant 86mm
1100W AC
1100W DC

Thermal and acoustics

Optimized thermal management makes the PowerEdge R820 cool and quiet. Benefiting from smart
cooling fan speed control, the R820 can keep both high performance and good acoustics across a
wide range of ambient temperatures from 10°C to 35°C (50°F to 95°F) and to extended ambient
temperature ranges (see Table 27). Operating environments for the R820 can vary from the data
center to general-use spaces. In typical a configuration, the R820 is suitable for an open office
environment.
Thermal design
The thermal design of the PowerEdge R820 reflects the following:
Multiple sensors are monitored for thermal feedback control: The PowerEdge R820

dynamically controls system cooling fan speed based on responses from all component
temperature sensors, including processors, hard disk drives, DIMMs, storage cards and the inlet
ambient temperature. Thermal control detects and responds to hardware configuration. Thermal
management adjusts cooling according to what the system really needs, and draws lower fan
power draw and generates lower acoustical noise levels than servers without such controls.
30 PowerEdge R820 Technical Guide
Figure 8. 750W power supply unit
Table 17. Power supply efficiency
Class
Platinum
Titanium
Platinum
N/A
Efficiency targets by load
10% 20%
82.0% 90.0%
90.0% 94.0%
89.0% 93.0%
80.0% 88.0%
50% 100%
94.0% 91.0%
96.0% 91.0%
94.5% 92.0%
91.0% 88.0%