HP Integrity rx7620 Server - User Service Guide, Sixth Edition

• Central station air handling units with remote refrigeration equipment. These systems are
usually located outside the computer room.
• Scalable overhead distribution system. These systems distribute water overhead to air heat
exchangers, which cool the air locally over the servers. A system called DataCool
TM
is
primarily used in high density environments of 100 to 500 watts per square foot.
Basic Air Distribution Systems
A basic air distribution system includes supply air and return air.
An air distribution system should be zoned to deliver an adequate amount of supply air to the
cooling air intake vents of the computer system equipment cabinets. Supply air temperature
should be maintained within the following parameters:
• Ceiling supply system—From 55° to 60° F (12.8 το 15.6° C)
• Floor supply system—At least 60° F (15.6° C)
If a ceiling plenum return air system or a ducted ceiling return air system is used, the return air
grilles in the ceiling should be located directly above the computer equipment cabinets.
The following three types of air distribution system are listed in order of recommendation:
• Underfloor air distribution system. Downflow air conditioning equipment located on the
raised floor of the computer room uses the cavity beneath the raised floor as plenum for the
supply air.
Perforated floor panels (available from the raised floor manufacturer) should be located
around the perimeter of the system cabinets. Supply air emitted though the perforated floor
panels is then available near the cooling air intake vents of the computer system cabinets.
• Ceiling plenum air distribution system. Supply air is ducted into the ceiling plenum from
upflow air conditioning equipment located in the computer room or from an air handling
unit (remote).
The ceiling construction should resist air leakage. Place perforated ceiling panels (with down
discharge air flow characteristics) around the perimeter of the system cabinets. The supply
air emitted downward from the perforated ceiling panels is then available near the cooling
air intake vents of the computer system cabinets.
Return air should be ducted back to the air conditioning equipment though the return air
duct above the ceiling.
• Above ceiling ducted air distribution system. Supply air is ducted into a ceiling diffuser
system from upflow air conditioning equipment located in the computer room or from an
air handling unit (remote).
Adjust the supply air diffuser system grilles to direct the cooling air downward around the
perimeter of the computer system cabinets. The supply air is then available near the cooling
air intake vents of the computer system cabinets.
Table C-1 Computer Room Environment
Non-Operating
Ranges
Maximum Rate of Change
(per hour)
Recommended
Operating Range
Operating LimitsParameter
-40° C to +70° C20° C/hr (no tape media)
10° C/hr (with tape media)
68° to 77° F
(20° to 25° C)
41° to 95° F
(5° to 35° C)
Temperature
1
90% RH
non-condensing @
65° C (149° F)
30% RH/hour
non-condensing
40% to 55% RH
non-condensing
15% to 80% with no
condensation (40% to 55%
recommended)
Humidity
1 The temperature ranges stated are at 0 to 5,000 ft. The maximum operating temperature must be derated by 1° C/1,000
ft from 5,000 to 10,000 ft.
188 General Site Preparation Guidelines