Trane CVGF-SVU02B-E4 Operation And Maintenance Manual page 8

Compressor second stage -
Refrigerant vapor leaving the
first stage compressor is mixed
with cooler refrigerant vapor
from the economizer. This
mixing lowers the enthalpy of
the vapor entering the second
stage. The second stage
impeller accelerates the vapor,
further increasing its
temperature and pressure to
state point 4.
Condenser - Refrigerant vapor
enters the condenser where the
system cooling load and heat of
compression are rejected to the
condenser water circuit. This
heat rejection cools and
condenses the refrigerant vapor
to a liquid at state point 5.
8
General
Information
Economizer and refrigerant
orifice system - Liquid
refrigerant leaving the
condenser at state point 5 flows
through the first orifice and
enters the economizer to flash a
small amount of refrigerant at
an intermediate pressure
labeled P1. Flashing some liquid
refrigerant cools the remaining
liquid to state point 8.
Another benefit of flashing
refrigerant is to increase the
total evaporator Refrigeration
Effect from RE' to RE. The
economizer provides around 4
percent energy savings
compared to chillers with no
economizer.
To complete the operating cycle,
liquid refrigerant leaving the
economizer at state point 8
flows through a second orifice.
Here refrigerant pressure and
temperature are reduced to
evaporator conditions at state
point 1.
An innovative design feature of
the CVGF chiller is maximizing
the evaporator heat transfer
performance while minimizing
refrigerant charge requirements.
This is accomplished by the
Trane-patented falling film
evaporator design. The amount
of refrigerant charge required in
CVGF is less than that in
comparably sized chillers of
flooded evaporator design.
CVGF-SVU02B-E4