3
COOLING OPERATION
High-Temperature Generator
(HGE)
The gas burner heats a dilute lithium
bromide
solution
in
the
High-
Temperature Generator resulting in a
release of superheated refrigerant vapor.
The dilute solution becomes more
concentrated
due
to
this
release.
Gravity,
temperature,
and
pressure
differences push the more concentrated
solution through Heat Exchangers to
recycle heat before the concentrated
solution is sent to the Absorber
(ABS)
.
After
release,
the
superheated
refrigerant vapor flows through the Low-
Temperature Generator
(LGE)
tubing
bundle and is used as the heat source for
the dilute solution that the LGE contains.
Most, if not all, of the refrigerant vapor
will condense into liquid refrigerant
during this process. Ultimately, this
tubing dumps the liquid refrigerant into
the Condenser
(COND)
.
Low-Temperature Generator
(LGE)
After
release,
the
superheated
refrigerant vapor heats dilute lithium
bromide solution in the Low-Temperature
Generator. The refrigerant vapor
liberated from this solution flows into the
Condenser while the lithium bromide
solution becomes more concentrated.
Gravity,
temperature,
and
pressure
differences push this more concentrated
solution through Heat Exchangers to
recycle heat before the concentrated
solution is sent to the Absorber.
Condenser
(COND)
In the Condenser, refrigerant vapor is
condensed on the outer surface of the
condenser tubing bundle. Latent heat is
removed by the cooling water that flows
inside this tubing bundle. The heat
absorbed by the cooling water is rejected
to a cooling tower or alternative system.
The liquid refrigerant that drips off the
tubing bundle joins the liquid refrigerant
that resulted from the operation of the
LGE and accumulates in the condenser
sump. Liquid refrigerant is routed from
the
condenser
sump
through
an
electronic expansion valve which meters
the liquid refrigerant as required into the
Evaporator
(EVA)
.
Evaporator
(EVA)
In the Evaporator, liquid refrigerant is
exposed to a substantially deeper
vacuum than in the Condenser due to the
influence of the Absorber. As the liquid
refrigerant flows over the surface of the
Evaporator tubing bundle, it boils and
removes heat from the chilled water
flowing inside the Evaporator tubing
bundle. The heat removed from the
chilled water circuit is equal to the latent
heat of the refrigerant, roughly 1000 BTU
per pound of liquid refrigerant boiling into
refrigerant vapor.
Absorber
(ABS)
The Evaporator and the Absorber
share the same space. A deep vacuum
in the ABS is maintained by the affinity of
the concentrated solution for refrigerant
vapor. The concentrated solution flows
over the outside of the Absorber tubing
bundle where it is cooled by the cooling
water flowing inside the Absorber tubing
bundle. When the concentrated solution
is cooled, it develops an even greater
affinity for the refrigerant vapor. The
heat absorbed by the cooling water is
rejected to a cooling tower or alternative
system.
The deep level of vacuum in the ABS
section is maintained by the action of the
concentrated solution absorbing the
refrigerant vapor that is being generated
by the EVA during its normal operation.
