Dunham-Bush WCFX-E Series, Руководство пользователя

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UNIT FEATURES
Remote Monitoring
Vision 2020i controller can be completed with an optional
RS485 communications card and NETVISOR software
for remote monitoring and controlled from a PC terminal
and optional phone modem.
With various optional add-on cards the Vision2020i
controller can also be interfaced directly to the Building
Management System (BMS) with the standard open
communication protocols using MODBUS, LONWORKS,
BACNET MSTP as well as over IP.
This sophisticated feature makes servicing easier and
more convenient to the system. The controller as
standard is additionally equipped with history files which
may be used to take logs which may be retrieved via the
phone modem. Now owners of multiple buildings have a
simple and inexpensive method of investigating potential
problems quickly and in a highly cost effective manner.
REFRIGERATION CYCLE
Dunham-Bush Water Cooled Screw Flooded Chillers are
designed for efficiency and reliability. The rotary screw
compressor is a positive displacement, variable capacity
compressor that will allow operation over a wide variety of
conditions.
Even at high head and low capacity, a difficult condition
for centrifugal compressors, the rotary screw performs
easily. It is impossible for this positive displacement
compressor to surge.
The refrigerant management system, however, is very
similar to centrifugal water chillers and is shown in the
refrigerant cycle diagram below.
Liquid refrigerant enters the flooded evaporator uniformly
where it absorbs heat from water flowing through the
evaporator tubes. The vaporized refrigerant is then drawn
into the suction port of the compressor where the positive
displacement compression begins.
This partially compressed gas is then joined with
additional gas from the economizer as the rotors rotate
past the vapor injection port at an intermediate pressure.
Compressed gaseous refrigerant is then discharged into
the integral oil separator where oil which is contained in
the refrigerant vapor, is removed and resumed to the oil
sump.
Fully compressed and superheated refrigerant is then
discharged into the condenser, where water in the
condenser tubes cools and condenses the refrigerant. A
portion of liquid refrigerant is tapped passes through the
first expansion device and into the economizer for further
subcooling of main liquid refrigerant flow.
The gaseous refrigerant is then drawn out of the flash
economizer and into the vapor injection port of the
compressor. The remaining liquid refrigerant then passes
through a second expansion device which reduces
'refrigerant pressure to evaporator levels where it is then
distributed evenly into the evaporator.
This delivers outstanding efficiency and total energy
savings through the utilization of economizer cycle.
Increases capacity by as much as 12% with only 7%
extra absorbed power.