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INTRODUCTION
Refrigeration Cycle Description
The cooling cycle of KCHH series can be described using
the following pressure–enthalpy chart.①, ②, ③, ④,
and ⑤ in the following chart shows the conditions of
the refrigerant. The refrigerant comes into the compres-
sor and moves to the internal suction inlet section of the
compressor. The oil inside the compressor seals the gap
between the compressor scrolls and provides lubrication
for the bearing to help the compression of the refrigerant.
During this time, the refrigerant is compressed and is dis-
charged to the air cooled condenser. (②) The compressed
refrigerant passes through the air cooled condenser and
exchanges the heat with the outdoor air. The condensed
refrigerant then passes the condenser to be overcooled (②
→ ③ → ④). The refrigerant that passed through the condenser expands in the electronic expansion valve to flow to the evaporator (④ → ⑤).
The refrigerant is evaporated in the shell and tube type heat exchanger, the evaporator (⑤ → ①). Liquid refrigerant of low temperature pressure
passes through the evaporator to cool the water flowing into the evaporator and the refrigerant itself receives the heat to evaporate to gas condition.
(①) The refrigerant continues to change the phase and continuously repeats the cooling cycle. For heating the refrigerant flow is in the reverse
direction to provide hot water.
Lubrication System
Oil is efficiently separated inside the scroll compressor, and even when the cycle operates, most of the oil remains inside the scroll compres-
sor. Only a part of the oil will be mixed with the refrigerant to be circulated within the cycle.
Partial Load Operation
Each cooling cycle operates independently; one (1) cooling cycle
includes two (2) inverter compressors.
Two (2) inverter compressors increase the rpm after initial start
to gradually increase the capacity. The end user will experience
smooth operation of the LG KCHH chiller as the capacity required is
matched to the required load. The LG KCHH will out perform stag-
ing systems and the variance in loop temperature is reduced with
the liner performance of the KCHH compressors. LG KCHH chillers
have efficient partial load performance.
Continuous operation at a capacity less than 20% of total capacity
is not guaranteed. System could enter into a safety run mode and
begin to cycle off compressors if the temperature difference between
entering water and leaving water is less then 4 degrees Fahrenheit.
The system will allow the difference in the entering water and leav-
ing water to increase above 4 degrees Fahrenheit and then run at
a minimum capacity at or above 20% of total capacity. If loop tem-
perature is extremely critical and run conditions below 20% of total
capacity are possible the engineer should provide enough storage
and increase the total loop design to off set this potential.
16
Figure 2: LG Chiller Pressure-Enthalpy Diagram.
Pressure
Due to our policy of continuous product innovation, some specifications may change without notification.
©LG Electronics U.S.A., Inc., Englewood Cliffs, NJ. All rights reserved. "LG" is a registered trademark of LG Corp.
Figure 3: Partial Load Operation Diagram.
Cooling Capacity
Inverter
Compressor 1
Capacity (%)
100%
80%
60%
40%
20%
40%
60%
C
o
i l o
g n
c
p a
c a
Hot-Gas
Suction
-
Compressor
Enthalpy
Inverter
Compressor 2
Load (%)
80%
100%
S y t i
a t
c i t
s
e p
d e
o c
m
p
e r
s s
r o
1
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