IBM 8408-44E Site And Hardware Planning page 76

Attention:
The overpressure safety device must meet the following requirements:
v Comply with ISO 4126-1.
v Be installed so that it is easily accessed for inspection, maintenance, and repair.
v Be connected as close as possible to the device that it is intended to protect.
v Be adjustable only with the use of a tool.
v Have a discharge opening that is directed so that discharged water or fluid does not create a hazard or
be directed toward any person.
v Be of adequate discharge capacity to ensure that the maximum working pressure is not exceeded.
v Be installed without a shutoff valve between the overpressure safety device and the protected device.
Read the following guidelines before you design the installation:
v A method for monitoring and setting the total flow rate that is delivered to all of the heat exchangers is
required. This can be a discrete flowmeter that is built into the flow loop or a flowmeter within the
secondary loop of the coolant distribution unit (CDU).
v After you set the total flow rate for all of the heat exchangers by using a flowmeter, it is important to
design the plumbing so that it provides the flow rate that you want for each heat exchanger and
provides a way to verify the flow rate. Other methods, such as inline or external flowmeters, can
provide a more accurate method for setting the flow rate through the individual shutoff valves.
v Design the flow loop to minimize the total pressure drop within the flow loop. The Optional Low
Impedance Quick Connect feature cannot use the Parker quick-connect couplings that are used on the
heat exchanger because of the excessive pressure drop that is associated with flowing through four
quick-connect pairs in series. These must be very low, near 0, flow impedance quick connects.
Alternatively, these quick connects can be eliminated and replaced with a hose barb connection.
Manifolds and piping:
Manifolds that accept large-diameter feed pipes from a pump unit are the preferred method for
splitting the flow of water to smaller-diameter pipes or hoses that are routed to individual heat
exchangers. Manifolds must be constructed of materials that are compatible with the pump unit
and related piping. The manifolds must provide enough connection points to allow a matching
number of supply and return lines to be attached, and the manifolds must match the capacity
rating of the pumps and the loop heat exchanger (between the secondary cooling loop and the
building chilled-water source). Anchor or restrain all manifolds to provide the required support
to avoid movement when quick-connect couplings are connected to the manifolds.
Example of manifold supply pipe sizes:
v Use a 50.8 mm (2 in.) or larger supply pipe to provide the correct flow to three 19 mm (0.75
in.) supply hoses, with a 100 kW coolant distribution unit (CDU).
v Use a 63.5 mm (2.50 in.) or larger supply pipe to provide the correct flow to four 19 mm (0.75
in.) supply hoses, with a 120 kW CDU.
v Use an 88.9 mm (3.50 in.) or larger supply pipe to provide the correct flow to nine 19 mm (0.75
in.) supply hoses, with a 300 kW CDU.
To stop the flow of water in individual legs of multiple circuit loops, install shutoff valves for
each supply and return line. This provides a way to service or replace an individual heat
exchanger without affecting the operation of other heat exchangers in the loop.
To ensure that water specifications are being met and that the optimum heat removal is taking
place, use temperature and flow metering (monitoring) in secondary loops.
Anchor or restrain all manifolds and pipes to provide the required support and to avoid
movement when quick-connect couplings are being attached to the manifolds.
Flexible hoses and connections to manifolds and heat exchangers:
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Site and hardware planning