HP Modular Cooling System manual watts is calculated as follows

Server blade systems and 1U servers let you assemble high-density infrastructures; however, these systems create much more heat per square foot of floor space and more hot spots. In instances like this, the open-area approach cannot keep up with the demand for cool air.

Figure 2 compares two examples of server loading for a 42U rack. In Figure 2A, our rack contains 20 HP ProLiant DL380 G5 servers, each consuming approximately 424 watts for a total rack consumption of 8.47 kW. In Figure 2B, our rack contains 42 dual-processor DL160 G6 servers consuming 383 watts per server for a total rack consumption of over 16 kW of power.

Figure 2: Examples of power consumption in 42U IT equipment racks with different server loads

A:ProLiant DL380 G5 2U servers

(20 servers @ 423.9 W per server)

8.47 kW 20 servers

B:ProLiant DL160 G6 1U servers (42 servers @ 383 W per server)

16.1 kW 42 servers

4.23 kW 10 servers 8.0 kW 21 servers

Power	Power
consumption	consumption

Higher power consumption produces more heat. Virtually all power consumed by rack-mounted equipment is converted to sensible heat, which increases the temperature in the environment. The sensible heat load is typically expressed in British Thermal Units per hour (BTU/hr) or watts, where

1 W equals 3.413 BTU/hr. The rack’s heat load in BTU/hr can be calculated as follows: Heat Load = Power [W] × 3.413 BTU/hr per watt

For example, the heat load for a ProLiant DL160 G6 server in a 2P configuration consuming

383 watts is calculated as follows:

383 W × 3.413 BTU/hr/W =1307 BTU/hr

This means that the heat load of our fully-loaded 42U rack of DL160 G6 servers is 54,901 BTU/hr. In the United States, cooling capacity is often expressed in "tons" of refrigeration, which is derived by dividing the sensible heat load by 12,000 BTU/hr per ton. Therefore, the cooling requirement for our rack of DL160 G6 servers is computed as follows:

54,901 BTU/hr ÷ 12,000 BTU/hr per ton = 4.58 tons

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