York YHAU-CE-JE Series, Установка, эксплуатация и обслуживание, Страница: 20 / 136

JOHNSON CONTROLS
20
FORM 155.33-ICOM2.EN.GB
ISSUE DATE: 12/4/2017
SECTION 2 – PRODUCT DESCRIPTION
WASTE HOT WATER-DRIVEN GENERATOR
AND LOW TEMPERATURE GENERATOR
The upper section is the waste hot water-driven genera-
tor. There, the waste hot water heats the dilute solution
from the low temperature heat exchanger.
The lower section is the low temperature genera-
tor. There, the hot refrigerant from the high tem-
perature generator heats the dilute solution com-
ing from the waste hot water-driven generator.
The refrigerant vapor from the high temperature
generator condenses into liquid and flows to the
condenser.
The low temperature generator is a falling liquid film
type.
LD21524
Waste Hot
Water In
Waste Hot
Water Out
Concentrated
Solution Out
Dilute Solution
In
CONDENSER
The refrigerant vapor from the low temperature gener-
ator as well as the condensed refrigerant from the high
temperature generator enter the condenser. There, they
condense into a liquid state using the cooling (condens-
er) water from the absorber section. The cooled refrig-
erant is sent to the bottom evaporator section through a
U-pipe (liquid seal). This completes the cooling cycle.
Condenser
LD19980_a5
Condensed
Refrigerant
Cooling Water
Outlet
CRYSTALLIZATION
All absorption chillers that use lithium bromide and
water as the solution and refrigerant pair are subject to
crystallization. This is due to the fact that some areas of
the unit operate with solution liquid concentration lev-
els that are only possible at temperatures higher than
the normal ambient temperature surrounding the unit.
For example, the solution concentration in the genera-
tor of a single effect absorption unit is typically 64.3%
lithium bromide by weight. That concentration begins
to crystallize at 43.3 °C.
Crystallization happens when the LiBr solution tem-
perature drops too low or the concentration is too high.
The LiBr solution becomes like slush. At this point, the
LiBr solution cannot absorb any more water and will
start to solidify (crystallize).
Crystallization occurs in the solution heat exchanger.
It may also happen in the generator. Pipes that are not
well insulated and are located in rooms where the tem-
perature can affect the solution as it moves through the
pipes are also subject to crystallization.
You can prevent crystallization by making sure you
keep the solution temperature high and the solution
concentration at the optimum percentage (64%).