York YHAU-CE-JE Series, Установка, эксплуатация и обслуживание, Страница: 17 / 136

JOHNSON CONTROLS
17
SECTION 2 – PRODUCT DESCRIPTION
FORM 155.33-ICOM2.EN.GB
ISSUE DATE:12/4/2017
2
EVAPORATOR
Liquid refrigerant enters the evaporator where it is dis-
tributed over the top of the tube bundle. The tubes used
in the evaporator are made of low residual phosphorus
deoxidized copper. They are finned. The wall thickness
before the finning is 0.6 mm.
The chilled water returns through the tubes as refrig-
erant droplets cover them. The heat from the water
causes the refrigerant to flash from a liquid to a vapor.
The temperature at which this happens depends on the
evaporator shell pressure. The pressure is dictated by
the absorber section of the chiller-heater.
The refrigerant vapor passes through the mist elimi-
nators. It then flows into the absorber section of the
chiller-heater. As the liquid refrigerant passes through
the evaporator tubes, more and more refrigerant vapor-
izes. The refrigerant that remains in a liquid state at
the bottom drains into the refrigerant tank. It is then
pumped up to the top of the tube bundle where the pro-
cess is repeated.
Mist Eliminators
LD21521
Refrigerant Pump
LG4
Evaporator
(Upper)
Evaporator
(Lower)
Chilled
Water
Out
Chilled
Water
In
Dilute Solution Out
ABSORBER
The concentrated LiBr solution enters the absorber
section of the chiller-heater. There it is sprayed over
the absorber tube bundle. The tubes used in the absorb-
er are the same as those used in the evaporator. See
Evaporator on page 17 for more information.
Because the vapor pressure of the concentrated solu-
tion is very low, the refrigerant (water) vapor from the
evaporator flows into the absorber where it is absorbed
by the LiBr solution. The concentration of the LiBr so-
lution lowers as the refrigerant (water) is absorbed into
the solution.
This dilution process generates heat. If the solution is
not cooled, the process stops when the solution tem-
perature rises. There is also a corresponding rise in the
vapor pressure.
The water flowing in the absorber tube bundle comes
from the cooling tower. It cools the LiBr solution as it
flows over the tube bundle. This allows the absorption
process to continue. The solution becomes more dilute
as it absorbs the refrigerant vapors. When the LiBr
solution reaches the bottom of the absorber section, it
enters the solution pump. The liquid is then pumped to
the generators.
LD21522
Absorber
(Upper)
Absorber
(Lower)
Cooling Water In
Cooling Water
to Condenser
Concentrated
Solution In
Dilute Solution Out