Estimate rack power consumption from servers, racks, and wattage, plus daily or period energy use, estimated energy charges, and heat-load equivalents.

Use measured average server load. This estimate excludes other IT equipment; cooling output is a heat-load equivalent, not equipment sizing.

Suggestions are illustrative, not verified rack capacities.

Suggestions are illustrative; actual load depends on hardware and use.

Power Rack Consumption Formula

The following formula is used to calculate the total IT (server) power for a group of racks in a data center.

PC = S × W × R
  • Where PC is the total IT power for all racks (W) when W is entered in watts.
  • S is the number of servers per rack
  • W is the power (wattage) of each server (W)
  • R is the total number of racks in the data center.

To calculate the total rack IT power, multiply the number of servers per rack by the number of racks, then multiply that result by the average power consumed by each server. To convert watts to kilowatts (kW), divide by 1,000.

What is a power rack?

Definition:

In a data center context, the more common term is a server rack, and “rack power” refers to the electrical load used by the equipment in that rack (often distributed via rack PDUs). Note: “power rack” is also a common term for a weightlifting rack, so the term can be ambiguous without context.

How to calculate power rack consumption?

Example Problem:

The following formula is used to calculate the total IT (server) power for a group of racks.

First, determine the number of servers per rack. For this data center, there are 10 servers per rack.

Next, determine the total number of racks. In this example, there are 100 racks in the data center.

Next, determine the power consumed by each server. These servers use 50 watts each.

Finally, calculate the total IT power using the formula above:

PC = S * W * R

PC = 10 * 50 * 100

PC = 50,000 W = 50 kW