IBM PureFlex System and IBM Flex System Products and Technology

134 IBM PureFlex System and IBM Flex System Products and Technology

For implementations where the front anti-tip plate is not required, an air baffle/air recirculation

prevention plate is supplied with the rack. You might not want to use the plate when an airflow

tile must be positioned directly in front of the rack.

This air baffle shown in Figure 4-61 can be installed to the lower front of the rack. It helps

prevent warm air from the rear of the rack from circulating underneath the rack to the front,

improving the cooling efficiency of the entire rack solution.

Figure 4-61 Recirculation prevention plate

4.13 IBM Rear Door Heat eXchanger V2 Type 1756

The IBM Rear Door Heat eXchanger V2 is designed to attach to the rear of these racks:

򐂰 IBM 42U 1100 mm Enterprise V2 Dynamic Rack

򐂰 IBM 42U 1100mm Enterprise V2 Dynamic Expansion Rack

It provides effective cooling for the warm air exhausts of equipment mounted within the rack.

The heat exchanger has no moving parts to fail and no power is required.

The rear door heat exchanger can be used to improve cooling and reduce cooling costs in a

high density HPC Enterprise Chassis environment.

Recirculation

prevention plate

135

The physical design of the door is slightly different to that of the existing Rear Door Heat

Exchanger (32R0712) marketed by IBM System x. This door has a wider rear aperture as

shown in Figure 4-62. It is designed for attachment specifically to the rear of either an IBM

42U 1100 mm Enterprise V2 Dynamic Rack or IBM 42U 1100mm Enterprise V2 Dynamic

Expansion Rack.

Figure 4-62 Rear Door Heat Exchanger

Attaching a rear door heat exchanger to the rear of a rack allows up to 100,000 BTU/hr or

30kw of heat to be removed at a rack level.

As the warm air passes through the heat exchanger, it is cooled with water and exits the rear

of the rack cabinet into the datacenter. The door is designed to provide an overall air

temperature drop of up to 25°C measured between air that enters the exchanger and exits the

rear.

136 IBM PureFlex System and IBM Flex System Products and Technology

Figure 4-63 shows the internal workings of the IBM Rear Door Heat eXchanger V2.

Figure 4-63 IBM Rear Door Heat eXchanger V2

The supply inlet hose provides an inlet for chilled, conditioned water. A return hose delivers

warmed water back to the water pump or chiller in the cool loop. It must meet the water supply

requirements for secondary loops.

137

Figure 4-64 shows the percentage heat removed from a 30 KW heat load as a function of

water temperature and water flow rate. With 18 Degrees at 10 (gpm), 90% of 30 kW heat is

removed by the door.

Figure 4-64 Heat removal by Rear Door Heat eXchanger V2 at 30 KW of heat

For efficient cooling, water pressure and water temperature must be delivered in accordance

with the specifications listed in Table 4-32. The temperature must be maintained above the

dew point to prevent condensation from forming.

Table 4-32 1756 RDHX specifications

140

130

120

110

100

90

80

70

60

50

% heat removal as function of water temperature and flow rate for

given rack power, rack inlet temperature, and rack air flow rate

4101214

% heat removal

Water flow rate (gpm)

Water

temperature

12°C *

14°C *

16°C *

18°C *

20°C *

68

22°C *

24°C *

Airflow

(cfm) = 2500

Rack Power

(W) = 30000

Tinlet, air

(C) = 27

Rear Door heat exchanger V2 Specifications

Depth 129 mm (5.0 in)

Width 600 mm (23.6 in)

Height 1950 mm (76.8 in)

Empty Weight 39 kg (85 lb)

Filled Weight 48 kg (105 lb)

Temperature Drop Up to 25°C (45°F) between air exiting and entering RDHX

Water Temperature Above Dew Point:

18°C ±1°C (64.4°F ±1.8°F) for ASHRAE Class 1 Environment

22°C ±1°C (71.6°F ±1.8°F) for ASHRAE Class 2 Environment

Required water flow rate (as measured at the

supply entrance to the heat exchanger)

Minimum: 22.7 liters (6 gallons) per minute, Maximum: 56.8 liters (15

gallons) per minute

138 IBM PureFlex System and IBM Flex System Products and Technology

The installation and planning guide provides lists of suppliers that can provide coolant

distribution unit solutions, flexible hose assemblies, and water treatment that meet the

suggested water quality requirements. It takes three people to install the rear door heat

exchanger. The exchanger requires a non-conductive step ladder to be used for attachment

of the upper hinge assembly. Consult the planning and implementation guides before

proceeding.

The installation and planning guides can be found at:

http://www.ibm.com/support/entry/portal/