Emerson CW089, Design Manual

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109 Liebert
®
CW
™
System Design Manual
2.6 A-FRAME CHILLED WATER COIL
The cooling coil shall be of A-frame design with a minimum of ____ ft
2
(m
2
) face area, ____ rows deep.
The coil shall be controlled by a 3-way modulating control valve. It shall be constructed of copper tubes
and aluminum fins and have a maximum face velocity of ____ ft per minute (m/s) at ____ CFM (m
3
).
The water circuit shall be designed to distribute water into the entire coil face area. The coil shall be
supplied with ____ °F (°C) entering water temperature, with a ____ °F (°C) temperature rise. The coil shall
require ____ GPM (l/s) of chilled water and the pressure drop shall not exceed ____ PSI (kPa). The entire
coil assembly shall be mounted in a stainless steel-condensate drain pan.
2.7 HUMIDIFIER
2.7.1 Infrared Humidifier—OPTIONAL
The humidifier shall be of the infrared type consisting of high-intensity quartz lamps mounted above and
out-of the water supply. The evaporator pan shall be stainless steel and arranged to be serviceable without
disconnecting water-supply lines, drain lines or electrical connections. The complete humidifier section
shall be pre-piped ready for final connection. The infrared humidification system shall use by-pass air to
prevent over-humidification of the controlled space. The auto-flush system shall automatically flush
deposits from the humidifier pan. System shall automatically fill and drain as well as maintain the required
water level based on conductivity.
A 1-in. (25-mm) air gap within the water-supply piping assembly shall prevent back-flow of the humidifier
supply water.
2.7.2 Steam Generating Canister Humidifier—OPTIONAL
A canister-type steam generating humidifier shall be factory-installed in the cooling unit and operated by
the Liebert iCOM
®
control system. It is complete with disposable cylinder, all supply and drain valves,
steam distributor and electronic controls. The need to change the canister is indicated on the Liebert iCOM
display. System shall automatically fill and drain as well as maintain the required water level based on
conductivity. An air gap within the humidifier assembly shall prevent back-flow of the humidifier supply
water.
2.7.3 Steam Grid Humidifier—OPTIONAL
A steam humidifier shall be the “Armstrong” steam separator type with an internal drying chamber and
steam-jacketed stainless-steel distribution manifold. Complete system shall include a pre-piped solenoid
control valve, steam trap, and cleanable Y-strainer. All mechanical-control components shall be located in
separate compartment, isolated from the air stream. The humidifier shall have a capacity of
________ lb/hr. (kg/h) at _______ PSIG (kPA) steam supply pressure.
2.8 REHEAT
2.8.1 Electric Reheat—OPTIONAL
The Thermal Management unit shall include a factory-installed reheat to control temperature during
dehumidification. The low-watt density, 304/304, stainless-steel, finned-tubular electric reheat coils. The
reheat section shall include UL/CSA recognized safety switches to protect the system from overheating.
2.8.2 Hot Water Reheat—OPTIONAL
The hot-water reheat coil shall have copper tubes and aluminum fins. The control system shall be factory
pre-piped with a 2-way motorized control valve. A cleanable Y-strainer is factory-installed on hot-water
supply line. Upflow model requires a 22 ¾-in. (58-cm) high plenum with grille.