FORM 160.84-EG1 (617)
JOHNSON CONTROLS
13
Equipment Overview (Cont'd)
OPTISOUND CONTROL
YMC² chillers are equipped with the YORK OptiSound Control as standard. The YORK
OptiSound Control is a patented combination of centrifugal-chiller hardware and software
that reduces operational sound levels, expands the chiller operating range, and improves
chiller performance. The OptiSound Control feature continuously monitors the charac-
teristics of the compressor-discharge gas and optimizes the diffuser spacing to minimize
gas-flow disruptions from the impeller. This innovative technology improves operating
sound levels of the chiller and can reduce part-load sound levels below the full-load level.
In addition, the OptiSound Control provides the benefit of an expanded operating range.
It improves performance and reliability by minimizing diffuser-gas stall at off-design op-
eration, particularly at conditions of very low load combined with little or no condenser-
water relief. The elimination of the gas-stall condition can also result in improved chiller
efficiency at off design conditions.
OptiSpeed VSD
A VSD is factory-packaged and mounted on the YMC² chiller. It is designed to vary the
compressor motor speed by controlling the frequency and voltage of the electrical power
to the motor. The capacity control logic shall automatically adjust motor speed and com-
pressor diffuser geometry for maximum part-load efficiency by analyzing information fed
to it by sensors located throughout the chiller. See OptiView Control Center on page 17
for additional information.
HEAT EXCHANGERS
Shells
Evaporator and condenser shells are fabricated from rolled carbon steel plates with fu-
sion welded seams or carbon steel pipe. Carbon steel tube sheets, drilled and reamed to
accommodate the tubes, are welded to the end of each shell. Intermediate tube supports
are fabricated from carbon steel plates, drilled and reamed to eliminate sharp edges. The
refrigerant side of each shell is designed, tested, and stamped in accordance with ASME
Boiler and Pressure Vessel Code, Section VIII – Division I, or other pressure vessel code
as appropriate.
Tubes
Heat exchanger tubes are copper alloy high-efficiency, externally and internally enhanced
type to provide optimum performance. Utilizing the “skip-fin” tube design provides a
smooth internal and external surface at each intermediate tube support. This provides
extra wall thickness (up to twice as thick) and non work-hardened copper at the support
location, extending the life of the heat exchangers. Each tube is roller-expanded into the
tube sheets providing a leak-proof seal, and is individually replaceable.
Evaporator
The evaporator is a shell and tube, hybrid falling-film type heat exchanger. It contains a
balance of flooded and falling-film technology to optimize efficiency, minimize refrigerant
charge, and maintain reliable control. A specifically designed spray distributor provides
uniform distribution of refrigerant over the entire shell length to yield optimum heat trans-
fer. A suction baffle is located above the tube bundle to prevent liquid refrigerant carryover
To Next Page
Loading...
