HP ProLiant SL270s ISS Technology Update, Volume 9, Number 6 - Page 3

Energy savings We believe the MDC will cut energy use by 38% for a 100kW IT load based on increased efficiency for cooling power conversion. This is equivalent to reducing carbon dioxide emissions by approximately 400 tons annually. It will reduce energy use by: Reducing inefficiencies caused by raised floor cooling infrastructures, such as warm air mixing with cold air above and around server aisles Reducing the energy required to provide chilled water by using a single chilled water coil The grant requires that the MDC achieve a maximum Power Usage Effectiveness (PUE) ratio of 1.25, where PUE = total MDC load ÷ IT equipment load A typical data center has a PUE over 2.0, which means that for every watt the IT equipment consumes, the power and cooling resources consume an additional watt. Sea of Sensors reduces power costs HP engineers designed ProLiant G6 and G7 servers with several thermal sensors, or Sea of Sensors, placed throughout the chipset, memory, power, and I/O subsystems. The iLO management processor polls the sensors to gather system-wide temperature data and uses sophisticated algorithms to adjust the speed of individual system fans and maintain sufficient system cooling. The number of sensors varies by the server's make, model, and installed options. Sea of Sensors provide the minimum amount of cooling necessary by ramping up individual fans near hot spots and slowing down fans near cool spots. The temperature plot in Figure 2-1 shows how air warms as it flows from the front (left) to the back (right) of a server. Cool spots occur at the inlet (left) and hot spots occur around CPUs and some chipset components (center). HP engineers observe how the plot changes with different loads to gain a better understanding of a system's thermal behavior. This approach reduces power use and fan noise, and can help facilities increase server density due to greater overall efficiency. Because of this approach, the Sea of Sensors helps ProLiant servers achieve benchmark-level operations per second per watt (OPS/watt). Figure 2-1. HP visualization tool representation of system ―hot spots‖ and ―cool spots‖ 3