Rear-Door Heat Exchanger Performance; Rear-Door Heat Exchanger Specifications - IBM XIV Gen3 Series Planning Manual

Rear-door heat exchanger performance

This information describes the performance of the rear-door heat exchanger.
An example of expected performance of the rear-door heat exchanger is illustrated
in Figure 19 on page 73 for a typical inlet air temperature of 24 °C (75.2 °F), with a
fully populated rack near uniform power dissipation, 32 kW heat load, and the
node fans running near nominal fan speed (1530 cfm). By selecting the water inlet
temperature and water flow rate, you can estimate the indicated heat removal.
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IBM XIV Gen3 281x-11x, 281x-21x, and 281x-314 Planning Guide
Table 38. Rear-door heat exchanger specifications
Door specifications
Door size
v Depth: 142.6 mm (5.6 in.)
v Height: 1945.4 mm (76.6
in.)
v Width: 639 mm (25.2 in.)
Heat exchanger size
v Depth: 67 mm (2.6 in.)
v Height: 1791.3 mm (70.5
in.)
v Width: 438.6 mm (17.3 in.)
Door assembly weight
v Empty: 29.9 kg (66 lb)
v Filled: 35.6 kg (78.5 lb)
Door heat removal capacity
v For examples of door heat
removal capacity, see the
illustrations in "Rear-door
heat exchanger
performance."
v In general, the door heat
removal capacity
percentage increases if one
or more of the following
events occur:
– The water temperature
decreases.
– The water flow
increases.
– The server heat loads
decrease.
v The door heat removal
capacity varies with water
temperature, water flow
rate, air temperature and
flow, and total heat load of
the servers; however, a
typical high-load cabinet
(20 - 32 kW or
approximately 70 000 - 105
000 Btu per hour) can
achieve 55% - 85% heat
removal.
Air specifications
Air movement
v Provided by servers and
other devices in the rack.
No additional air moving
devices are required.
Air source for servers
v Room air for front of the
rack. Air is exhausted from
the servers, moves through
the heat exchanger, and
exits into the room (open
loop).
Air temperature drop
v With high-heat-load
devices, up to 25°C (45°F)
between the air that exits
the rack devices and the
air that exits the heat
exchanger.
Air impedance
v Air pressure drop across
the heat exchanger is
equivalent to that of the
IBM acoustic rear door
Water specifications
Water source
v User-supplied, compliant
with specifications in this
document.
v Couplings on door: 19 mm
(0.75 in.)
v ID hose required: 19 mm
(0.75 in.) minimum
Water pressure
v Normal operation: <137.93
kPa (20 psi)
v Maximum: 689.66 kPa (100
psi)
v Pressure drop across heat
exchanger: approximately
48 kPa (7 psi)
Water volume
v Exchanger: approximately
2.8 liters (0.75 gallons)
v Exchanger plus supply
and return hoses to the
pump unit: Maximum of
approximately 15.1 liters
(4.0 gallons) excluding
pump unit piping and
reservoir
Water temperature
v If no dew point
control:18°C ±1°C (64.4°F
±1.8°F)
v If the water supply can
monitor and adjust the
relative-to-room dew
point, lower temperature
water is allowed.
Required water flow rate (as
measured at the supply
entrance to the heat
exchanger)
v Minimum: 22.7 liters (6
gallons) per minute
v Maximum: 37.9 liters (10
gallons) per minute