Table of Contents
Advertisement
INTRODUCTION
Refrigeration Cycle Description
The cooling cycle of ACHH 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 compressor
motor and cools the motor, and becomes overheated and
moves to the internal suction inlet section of the compres-
sor. 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 discharged 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 refriger-
ant 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 ACHH chiller as the capacity required is
matched to the required load. The LG ACHH will out perform stag-
ing systems and the variance in loop temperature is reduced with
the liner performance of the ACHH compressors. LG ACHH 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.
10
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
Hide quick links:
Advertisement
Table of Contents
