The newest ASHRAE recommended environmental range for class one and two data centers is 18 to 27° C (64.4 to 80.6° F) (dry bulb temperature). The allowable envelope which broadens the range to 32° C (90° F) is where IT equipment manufacturers test product in order to verify that the unit will function with no damage.
The move from 25° C to 27° C (77° F to 80.6° F) can have a negative impact on the IT equipment’s power dissipation. Most IT manufacturers start to increase air -moving device speed around 23° C (73° F) to improve component cooling and offset the increased ambient air temperature. Increases in the server intake temperature from 23° to 27°C will double the server fan energy consumption. A typical server fan consumes 10 percent of the total server energy at low temperatures.
This small change in input temperature to 27°C (80.6°F) will increase the total server energy by 10 percent. A move to 29°C (84.2°F) increases the total server energy by 20 percent.
Data center energy costs as a percent of total revenue are at an all time high. Energy costs are becoming the second highest operating cost in IT organizations, behind labor. A typical one-megawatt data center consumes 16 million kilowatt-hours of electricity a year.
It will be interesting to see if the new ASHRAE recommended environmental range changes operational expenditures and total cost of ownership.