Trane RTHD series Installation, Operation And Maintanance page 75

the lubricant and refrigerant are effectively divided using
an oil separator. The oil-free refrigerant vapor enters the
condenser at State Pt. 2. The lubrication and oil manage-
ment issues are discussed in more detail in the compres-
sor description and oil management sections that follow.
Baffles within the condenser shell distribute the com-
pressed refrigerant vapor evenly across the condenser
tube bundle. Cooling tower water, circulating through
the condenser tubes, absorbs heat from this refrigerant
and condenses it.
As the refrigerant leaves the bottom of the condenser
(State Pt. 3), it enters an integral subcooler where it is
subcooled before traveling to the electronic expansion
valve (State Pt. 4). The pressure drop created by the ex-
pansion process vaporizes a portion of the liquid refrig-
erant. The resulting mixture of liquid and gaseous re-
frigerant then enters the Evaporator Distribution system
(State Pt. 5). The flash gas from the expansion process is
internally routed to compressor suction, and while the
liquid refrigerant is distributed over the tube bundle in
the evaporator.
Figure 37. Refrigerant Flow Diagram
EXV
evaporator
gas pump
RTHD-SVX02H-EN
compressor
The RTHD chiller maximizes the evaporator heat transfer
performance while minimizing refrigerant charge re-
quirements. This is accomplished by metering the liquid
refrigerant flow to the evaporator's distribution system
using the electronic expansion valve. A relatively low
liquid level is maintained in the evaporator shell, which
contains a bit of surplus refrigerant liquid and accumu-
lated lubricant. A liquid level measurement device mon-
itors this level and provides feedback information to the
UC800 unit controller, which commands the electronic
expansion valve to reposition when necessary. If the lev-
el rises, the expansion valve is closed slightly, and if the
level is dropping, the valve is opened slightly such that a
steady level is maintained.
dual discharge lines only on C, D & E frame compressors
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Operating Principles Mechanical
dual discharge lines
only on C, D & E frame
compressors
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condenser
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