NonStop NS-Series Planning Guide (H06.04+)

Installation Facility Guidelines
HP Integrity NonStop NS-Series Planning Guide—529567-005
2-4
Cooling and Humidity Control
Cooling and Humidity Control
Do not rely on an intuitive approach to cooling design or to simply achieve an energy
balance—that is, summing up to the total power dissipation from all the hardware and
sizing a comparable air conditioning capacity. Today’s high-performance servers use
semiconductors that integrate multiple functions on a single chip with very high power
densities. These chips plus high-power-density mass storage and power supplies are
mounted in ultra-thin server and storage enclosures, which are then deployed into
computer racks in large numbers. This higher concentration of devices results in
localized heat, which increases the potential for hot spots that can damage the
equipment.
Additionally, variables in the installation site layout can adversely affect air flows and
create hot spots by allowing hot and cool air streams to mix. Studies have shown that
above 70°F (20°C), every increase of 18°F (10°C) reduces long-term electronics
reliability by 50%.
Because of high heat densities and hot spots, an accurate assessment of air flow
around and through the server equipment and specialized cooling design is essential
for reliable server operation.
Cooling airflow through each enclosure in the Integrity NonStop NS-series server is
front-to-back. Consult with your HP cooling consultant or your heating, ventilation, and
air conditioning (HVAC) engineer.
Because each modular cabinet houses a unique combination of enclosures, use the
Heat Dissipation Specifications and Worksheet on page 3-10 to calculate the total heat
dissipation for the hardware installed in each cabinet. For air temperature levels at the
site, refer to Operating Temperature, Humidity, and Altitude on page 3-10.
Weight
Modular cabinets for Integrity NonStop NS-series servers have a foot print and height
comparable to NonStop S-series servers with stacked enclosures. But each populated
modular cabinet in Integrity NonStop NS-series servers can be more than twice as
heavy as a NonStop S-series server stack. Because each modular cabinet houses a
unique combination of enclosures, total weight must be calculated based on what is in
the specific cabinet, as described in Modular Cabinet and Enclosure Weights With
Worksheet on page 3-9.
Note. Failure of site cooling with the server continuing to run can cause rapid heat buildup and
excessive temperatures within the hardware. Excessive internal temperatures can result in full
or partial system shutdown. Ensure that the site’s cooling system remains fully operational
when the server is running.