Figure 10-21.-Basic absorption cycle.
known as a WEAK solution. Here, in the generator
section of the plant, the weak solution is rejuvenated for
reuse as a STRONG solution. The generator pump
pumps the weak solution from the weak solution section
of the absorber up to the generator.
In the generator, the weak lithium bromide solution
is sprayed out over steam tubes that heat the solution and
drive the water vapor out of the solution. The strong
solution thus produced flows back into the absorber for
reuse. The water vapor driven out of the solution flows
from the generator into the condenser where it is
condensed by circulating seawater for reuse as a
refrigerant. The condensed vapor flows into the
evaporator and down to the refrigerant tray.
A regenerative heat exchanger is provided in the
system for the lithium bromide solution. The weak
solution must be heated to drive out the water vapor; the
strong solution must be cooled to absorb water vapor.
The regenerative heat exchanger aids in this process by
cooling the strong solution and preheating the weak
solution in the cycle.
Seawater (condensing) flow is provided through the
absorber section. It cools the strong solution returning
from the generator and removes the heat produced as the
lithium bromide solution absorbs the water vapor. The
outlet seawater from the absorber is the inlet water for
the condenser.
The absorber pump and the generator pump are
driven by a common electric motor. Therefore, the two
pumps are referred to cumulatively as the
absorber/generator pump.
A purge system (not shown) consists of a pump, an
eductor, and a purge tank. The system is provided with
the lithium bromide absorption system to keep air and
noncondensables out of the evaporator/absorber shell.
10-23
