U.S. patent application number 11/552303 was filed with the patent office on 2007-05-03 for method and apparatus for removing partial overload in an air conditioner.
This patent application is currently assigned to LG ELECTRONICS INC.. Invention is credited to Jeong Taek PARK, Jae Hoon SIM, Chan Ho SONG.
Application Number | 20070095083 11/552303 |
Document ID | / |
Family ID | 37965242 |
Filed Date | 2007-05-03 |
United States Patent
Application |
20070095083 |
Kind Code |
A1 |
PARK; Jeong Taek ; et
al. |
May 3, 2007 |
METHOD AND APPARATUS FOR REMOVING PARTIAL OVERLOAD IN AN AIR
CONDITIONER
Abstract
A method for removing a partial overload in an air conditioner,
which includes determining whether a plurality of indoor units
provided in the air conditioner includes at least one indoor unit
operating in an overload state; and performing a partial overload
operation to increase the amount of a refrigerant introduced into a
corresponding evaporator of the at least one indoor unit when the
at least one indoor unit is operating in the overload state.
Inventors: |
PARK; Jeong Taek;
(Gyeonggi-do, KR) ; SONG; Chan Ho; (Gyeonggi-do,
KR) ; SIM; Jae Hoon; (Seoul, KR) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN, P.L.C.
1950 ROLAND CLARKE PLACE
RESTON
VA
20191
US
|
Assignee: |
LG ELECTRONICS INC.
20, Yoido-dong, Youngdungpo-gu,
Seoul
KR
150-875
|
Family ID: |
37965242 |
Appl. No.: |
11/552303 |
Filed: |
October 24, 2006 |
Current U.S.
Class: |
62/197 ; 62/198;
62/228.1 |
Current CPC
Class: |
F24F 11/30 20180101;
F25B 5/02 20130101; F25B 49/022 20130101; F25B 2400/0751 20130101;
F24F 2110/10 20180101; F25B 2700/2104 20130101 |
Class at
Publication: |
062/197 ;
062/198; 062/228.1 |
International
Class: |
F25B 41/00 20060101
F25B041/00; F25B 49/00 20060101 F25B049/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 28, 2005 |
KR |
10-2005-0102165 |
Claims
1. A method for removing a partial overload in an air conditioners
comprising: determining whether a plurality of indoor units
provided in the air conditioner includes at least one indoor unit
operating in an overload state; and performing a partial overload
operation to increase the amount of a refrigerant introduced into a
corresponding evaporator of the at least one indoor unit if it is
determined that the at least one indoor unit is operating in the
overload state.
2. The method as claimed in claim 1, further comprising: detecting
at least one indoor unit operating in the overload state by using a
detection signal of a temperature sensor provided in each of the
plurality of indoor units.
3. The method as claimed in claim 1, wherein the partial overload
operation comprises determining whether the overload state of the
at least one indoor unit continues beyond a predetermined period of
time; determining whether the plurality of indoor units include at
least another indoor unit operating in a normal load state; and
performing the partial overload operation if it is determined that
the overload state of the at least one indoor unit continues beyond
the predetermined period of time and the at least another indoor
unit is operating in the normal load state.
4. The method as claimed in claim 3, further comprising operating
the air conditioner according to the temperature of indoor air
detected by the at least one indoor unit and the at least another
indoor unit if it is determined that either the overload state of
the at least one indoor unit does not continue beyond the
predetermined period of time, or each of the at least one indoor
unit and the at least another indoor unit is operating in the
overload state.
5. The method as claimed in claim 3, wherein the at least another
indoor unit is a plurality of units.
6. The method as claimed in claim 1, wherein the increase in the
amount of the refrigerant introduced into the evaporator of the at
least one indoor unit also involves an increase in a refrigerant
compression capacity of a compressor.
7. The method as claimed in claim 6, wherein a plurality of
compressors are provided, and the refrigerant compression capacity
is increased by determining a refrigerant compression capacity
according to the operations of at least one of the plurality of
compressors that is currently driven, and selectively operating the
compressors based on the determination results.
8. The method as claimed in claim 1, wherein the amount of the
refrigerant introduced into the evaporator of the at least one
indoor unit is increased by controlling an expansion device
provided at a refrigerant inlet side of the evaporator of the at
least one indoor unit.
9. The method as claimed in claim 8, wherein the expansion device
is a linear expansion valve.
10. The method as claimed in claim 1, further comprising: operating
the air conditioner according to the temperature of indoor air
detected by each of the plurality of indoor units if the plurality
of indoor units is operating in a normal state.
11. An apparatus for removing a partial overload in an air
conditioner, comprising a controller that determines whether a
plurality of indoor units, provided in the air conditioner,
includes at least one indoor unit operating in an overload state,
wherein the controller performs a partial overload operation, such
that the amount of a refrigerant introduced into a corresponding
evaporator of the at least one indoor unit is increased, when the
at least one indoor unit is operating in the overload state.
12. The apparatus according to claim 11, further comprising: a
temperature sensor, provided in each of the plurality of indoor
units, that detects the overload state of the at least one indoor
unit operating in the overload state.
13. The apparatus according to claim 11, wherein the controller
determines whether the at least one indoor unit is in the overload
state for a time period longer than a predetermined period of time,
and wherein the controller determines whether the plurality of
indoor units include at least another indoor unit operating in a
normal load state; and wherein the controller performs the partial
overload operation when the at least one indoor unit has been in
the overload state for a period of time longer than the
predetermined period of time and the at least another indoor unit
is operating in the normal load state.
14. The apparatus according to claim 13, wherein the controller
operates the air conditioner according to the temperature of indoor
air detected by the at least one indoor unit and the at least
another indoor unit when either one of the overload state of the at
least one indoor unit is less than the predetermined period of
time, or each of the at least one indoor unit and the at least
another indoor unit is operating in the overload state.
15. The apparatus according to 11, wherein at least one of a
plurality of compressors, having a compression capacity smaller
than at least one of the remaining compressors, is stopped; and
wherein at least one of the remaining compressors, having a
compression capacity larger that the at least one of the plurality
of compressors, is driven to allow an increase in the amount of
refrigerant introduced into the corresponding evaporator.
16. The apparatus according to claim 11, wherein a plurality of
compressors are turned on to provide an increased compression
capacity.
17. The apparatus according to claim 11, wherein an expansion
device is provided at a refrigerant inlet side of the evaporator to
increase the amount of refrigerant introduced into the
evaporator.
18. The apparatus according to claim 17, wherein the expansion
device is a linear expansion valve.
19. The apparatus according to claim 11, wherein the at least
another indoor unit is a plurality of units.
20. The apparatus according to claim 11, wherein the controller
operates the air conditioner according to a detected temperature of
indoor air detected by each of the plurality of indoor units when
the plurality of indoor units is operating in a normal state.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. .sctn.119
to Korean Patent Application No. 10-2005-0102165 filed on Oct. 28,
2005, the entirety of which is hereby incorporated by
reference.
BACKGROUND OF THE INVENTION
[0002] This description relates to a method for removing partial
overload in an air conditioner.
[0003] In general, an air conditioner withdraws hot air from a room
and performs heat exchange at an evaporator in a refrigeration
cycle thereof. Then, the air conditioner discharges cold air
generated by the heat exchange into the room. The air conditioner
repeats these processes to cool the room.
[0004] Typically, the refrigeration cycle includes a closed circuit
having a compressor, a condenser, an expansion device and an
evaporator.
[0005] The compressor compresses a gaseous refrigerant of low
temperature and pressure and converts it into a gaseous refrigerant
of high temperature and pressure. The gaseous refrigerant of high
temperature and pressure converted by the compressor is condensed
in the condenser and then converted into a liquid refrigerant of
high temperature and pressure.
[0006] The liquid refrigerant of high temperature and pressure
condensed in the condenser is expanded in the expansion device and
then converted into a liquid refrigerant of low temperature and
pressure. The liquid refrigerant of low temperature and pressure
expanded in the expansion device is subjected to heat exchange with
indoor air in the evaporator and then evaporated and converted into
the gaseous refrigerant of low temperature and pressure.
[0007] The gaseous refrigerant of low temperature and pressure
generated by the heat exchange in the evaporator is converted again
into the gaseous refrigerant of high temperature and pressure in
the compressor.
[0008] That is, the refrigeration cycle including a closed circuit
consisting of the compressor, the condenser, the expansion device
and the evaporator repeatedly performs the compression,
condensation, expansion and evaporation of a refrigerant. The
refrigeration cycle carries out the heat exchange of indoor air
with the refrigerant in the evaporator to generate cold air and
then discharges the generated cold air into the room so that the
room can be cooled.
[0009] In the air conditioner in which such a refrigeration cycle
is operated, components such as the compressor and the condenser,
producing much noise and heat, are generally provided in an outdoor
unit.
[0010] On the contrary, the expansion device and the evaporator
that hardly produce noise and generate cold air are provided in an
indoor unit. The indoor and outdoor units are connected to each
other through a pipe.
[0011] Recently, in order to increase the cooling capacity of an
air conditioner, a multi-type air conditioner has been popularized,
in which an outdoor unit includes two or more compressors and a
plurality of indoor units are connected to one outdoor unit so as
to cool a plurality of rooms.
[0012] In a multi-type air conditioner having a plurality of indoor
units, chances are a cooling load increases only in a room where a
specific indoor unit is installed to come to an overload state,
whereas cooling loads in other rooms where the other indoor units
are installed do not increase only to maintain a constant
level.
[0013] In such a case, if the air conditioner is operated at a room
temperature detected in each of the indoor units, the cooling
capacity of an indoor unit installed in a room with an increased
cooling load is reduced while the cooling capacity of an indoor
unit installed in a room with a constant cooling load is increased
to cause the room to be excessively cooled so that a user may feel
a chill.
[0014] In an air conditioner having a plurality of indoor units,
therefore, it is necessary to correctly detect an indoor unit
operated in an overload state due to an increased cooling load, and
to increase the cooling capacity of only the indoor unit operated
in the overload state so that a corresponding room can be quickly
cooled
SUMMARY OF THE INVENTION
[0015] It is an object of the present invention to provide a method
for removing a partial overload in an air conditioner, wherein a
first indoor unit operating in an overload state due to an
increased cooling load is correctly detected from a plurality of
indoor units, and the cooling capacity of the detected indoor unit
is increased so that the first indoor unit can be operated in a
normal load state within a short period of time.
[0016] In the present invention for achieving the above object, a
change in the temperature of indoor air in a room with each of a
plurality of indoor units installed therein is used to detect a
first indoor unit, which is operating in an overload state due to
an increased cooling load, among the plurality of indoor units
provided in a multi-type air conditioner.
[0017] To this end, in the present invention, a temperature sensor
is provided in each of the plurality of indoor units to detect a
change in the temperature of indoor air. Based on the detected
change in the temperature of indoor air, the first indoor unit
operating in the overload state is detected.
[0018] There may be a case where although the first indoor unit has
an increased cooling load and thus is in the overload state, the
overload state does not continue but is maintained temporarily.
[0019] Accordingly, the present invention comprises determining
whether the overload state of the first indoor unit continues
beyond a predetermined period of time. If the overload state of the
first indoor unit continues beyond the predetermined period of
time, it is finally determined that the indoor unit is in the
overload state.
[0020] If it is finally determined that only the first indoor unit
is in the overload state and a plurality of second indoor units are
not in the overload state, the amount of the refrigerant introduced
into the first indoor unit, which is in the overload state, is
increased to increase the cooling capacity of the first indoor
unit.
[0021] Here, the present invention employs an expansion device such
as a linear expansion valve for controlling a flow rate of the
refrigerant so as to control the amount of the refrigerant
introduced into a specific indoor unit.
[0022] When the amount of the refrigerant introduced into the first
indoor unit, which is in the overload state, is increased, the
amount of a refrigerant introduced into each of the second indoor
units having constant cooling loads is decreased. Thus, there may
be a case where the cooling capacities of the second indoor units
are lowered.
[0023] Therefore, in a case where a plurality of compressors are
provided, the present invention determines the current operation
states of the compressors. If it is determined that the compressors
are not operating with maximum compression capacities, control is
made to increase the amount of the refrigerant introduced into the
first indoor unit and the compression capacities of the
compressors.
[0024] Thus, according to the present invention, without lowering
the cooling capacities of the second indoor units having constant
cooling loads, only the amount of the refrigerant introduced into
the first indoor unit, which is in the overload state, is increased
to increase the cooling capacity of the first indoor unit, thereby
rapidly cooling the room with the first indoor unit installed
therein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The present invention is further described in the detail
description which follows, in reference to the noted plurality of
drawings, by way of non-limiting examples of preferred embodiments
of the present invention, in which like characters represent like
elements throughout the several views of the drawings, and
wherein:
[0026] FIG. 1 is a schematic view showing the configuration of a
multi-type air conditioner to which a method for removing a partial
overload according to the present invention is applied;
[0027] FIG. 2 is a control block diagram of the air conditioner to
which the method for removing a partial overload according to the
present invention is applied; and
[0028] FIG. 3 is a flowchart illustrating the method for removing a
partial overload according to the present invention
DETAILED DESCRIPTION OF THE INVENTION
[0029] The particulars shown herein are by way of example and for
purposes of illustrative discussion of the embodiments of the
present invention only and are presented in the cause of providing
what is believed to be the most useful and readily understood
description of the principles and conceptual aspects of the present
invention. In this regard, no attempt is made to show structural
details of the present invention in more detail than is necessary
for the fundamental understanding of the present invention, the
description taken with the drawings making apparent to those
skilled in the art how the several forms of the present invention
may be embodied in practice.
[0030] FIG. 1 is a schematic view showing the configuration of a
multi-type air conditioner to which a method for removing a partial
overload according to the present invention is applied. Here,
reference numeral "100" designates an accumulator for supplying a
gaseous refrigerant of low temperature and pressure, and reference
numerals "110" and "120" designate first and second compressors,
respectively, for converting the gaseous refrigerant of low
temperature and pressure, which may be supplied by the accumulator
(100), into a gaseous refrigerant of high temperature and
pressure.
[0031] For example, the compression capacity of the first
compressor (110) may be about 60% of the total compression capacity
of a system and the compression capacity of the second compressor
(120) may be about 40% of the total compression capacity.
[0032] Reference numerals "112" and "122" designate back-flow
preventers or preventing means for preventing the gaseous
refrigerant of high temperature and pressure, which may be obtained
through by the first and second compressors (110, 120) compressing
the gaseous refrigerant of low temperature and pressure, from
flowing backward.
[0033] For example, check valves can be used as the back-flow
preventer or preventing means (112, 122) to prevent the refrigerant
from flowing backward. However, it should be appreciated that any
suitable preventers may be employed in order to prevent the
refrigerant from flowing backwards.
[0034] Reference numeral "130" designates a condenser. The
condenser (130) condenses the gaseous refrigerant of high
temperature and pressure, which may be obtained through the
compression by the first and second compressors (110, 120), into a
liquid refrigerant of high temperature and pressure.
[0035] Reference numerals "140a", "140b", . . . designate a
plurality of expansion devices. Each of the plurality of expansion
devices (140a, 140b, . . . ) expands the liquid refrigerant of high
temperature and pressure, which has been condensed in the condenser
(130), so that it can be converted into a liquid refrigerant of low
temperature and pressure.
[0036] Reference numerals "150a", "150b", designate a plurality of
evaporators installed in an outdoor unit.
[0037] Each of the evaporators (150a, 150b, . . . ) perform heat
exchange between the liquid refrigerant of lower temperature and
pressure, which has been expanded in the expansion devices (140a,
140b . . . ), and indoor air to generate cold air and to covert the
liquid refrigerant into a gaseous refrigerant of lower temperature
and pressure.
[0038] In the air conditioner described above, in a case where the
first compressor (110) or the second compressor (120) is operated,
the gaseous refrigerant of lower temperature and pressure, which
may be stored in the accumulator (100), is introduced into the
first compressor (110) or the second compressor (120) where the
refrigerant is compressed to be the gaseous refrigerant of high
temperature and pressure.
[0039] Here, the accumulator (100) functions to prevent damage to
the first and second compressors (110, 120) due to introduction of
the liquid refrigerant of lower temperature and pressure into the
compressors.
[0040] The gaseous refrigerant of high temperature and pressure,
which has been compressed by the first and second compressors (110,
120), may be introduced into the condenser (130) through the
back-flow preventing means (112, 122).
[0041] The condenser (130) condenses the gaseous refrigerant of
high temperature and pressure so that the refrigerant can be
converted into the liquid refrigerant of high temperature and
pressure. This liquid refrigerant of high temperature and pressure
may be expanded in each of the expansion devices (140a, 140b . . .
) and then converted into the liquid refrigerant of low temperature
and pressure.
[0042] The liquid refrigerant of low temperature and pressure may
be subjected to heat exchange with indoor air in each of the
evaporators (150a, 150b, . . . ) and then converted into the
gaseous refrigerant of low temperature and pressure, and cold air
generated by the heat exchange is discharged into a room so that
the room can be cooled.
[0043] The gaseous refrigerant of low temperature and pressure,
which has been evaporated in each of the evaporators (150a, 150b, .
. . ), may be collected in the accumulator (100), and the collected
gaseous refrigerant of low temperature and pressure is compressed
again by the first and second compressors (110, 120) and becomes
the gaseous refrigerant of high temperature and pressure. This
circulation of the refrigerant may be repeated.
[0044] FIG. 2 is a control block diagram of the air conditioner to
which the method for removing a partial overload according to the
present invention is applied. In FIG. 2, reference numeral "200"
designates a user input unit through which a user's command such as
an operation command or a control command for an air conditioner is
input according to a user's manipulation. Reference numeral "210"
designates a temperature detecting unit.
[0045] A temperature sensor (not shown) such as a thermostat may be
provided at each of a plurality of indoor units, and the
temperature detecting unit (210) detects the temperature of a room
with each of the indoor units installed therein, using a detection
signal of the temperature sensor. Further, temperature in an
overload state to be detected by the temperature sensor may be a
preset temperature. In this regard, the temperature sensor may
detect the overload state when the temperature is above the preset
temperature.
[0046] Reference numeral "220" designates a control unit. The
control unit (220) controls the operation of the air conditioner
according to a user's command input through the user input unit
(200).
[0047] Further, the control unit (220) determines whether a
corresponding indoor unit is in an overload state, based on the
detection signal of the temperature detecting unit (210), and
controls the operation of the air conditioner according to the
determination on whether the indoor unit is in the overload
state.
[0048] Moreover, based on the detection signal of the temperature
detecting unit (210), the control unit (220) detects a first indoor
unit (e.g., at least one of a plurality of indoor units) of which a
cooling load is in an overload state, and then controls the
operation of the air conditioner to efficiently remove an overload
condition of the first indoor unit.
[0049] Reference numeral "230" designates a compressor driving
unit. The compressor driving unit (230) selectively drives the
first compressor (110) or the second compressor (120), or
simultaneously drives both the first compressor (110) and the
second compressor (120) according to the control of the control
unit (220).
[0050] Reference numeral "240" designates an expansion device
driving unit. The expansion device driving unit (240) drives the
expansion devices (140a, 140b, . . . ) according to the control of
the control unit (220), thereby adjusting the expansion amount of
the refrigerant.
[0051] In the air conditioner having the above construction, if a
command for operating the air conditioner is input through the user
input unit (200) (manipulated by a user), the control unit (220)
controls the compressor driving unit (230) according to the command
for operating the air conditioner so that the first compressor
(110) or the second compressor (120) can be driven, and also
controls the expansion device driving unit (240) to adjust the
opening/closing amounts of the expansion devices (140a, 140b, . . .
), thereby performing a cooling operation of the air
conditioner.
[0052] Furthermore, based on the detection signal of the
temperature detecting unit (210), the control unit (220) determines
whether there is an indoor unit, i.e., the first indoor unit, which
is operating in an overload state, among the plurality of indoor
units.
[0053] For example, assume that the first indoor unit with the
evaporator (150a) installed therein is operating in an overload
state.
[0054] If it is determined that the first indoor unit with the
evaporator (150a) installed therein is operating in an overload
state, the control unit (220) determines whether the overload state
of the first indoor unit continues beyond a predetermined period of
time (That is, if at least one indoor unit is in the overload state
for a time period longer than a predetermined (or preset) period of
time). If it is determined that the first indoor unit is operating
in the overload state beyond the predetermined period of time, the
control unit determines whether a plurality of second indoor units
(e.g. at least another of the plurality of indoor units) is also
operating in an overload state.
[0055] If it is determined that there is no first indoor unit
operating in the overload state, that the first indoor unit is
operating in the overload state but the overload state does not
continue beyond the predetermined period of time, or that the
plurality of second indoor units in addition to the first indoor
unit are also operating in the overload state, the control unit
(220) recognizes that a plurality of indoor units are operating in
the overload state. Then, the control unit (220) controls the
operation of the air conditioner according to the temperature of a
room with each of the indoor units installed therein, which is
detected by the temperature detecting unit (210), so that the air
conditioner can operate in a normal state.
[0056] If it is determined that the first indoor unit is operating
in the overload state beyond the predetermined period of time and
the plurality of second indoor units are not operating in the
overload state, the control unit (200) recognizes that only the
first indoor unit is operating in the overload state and then
determines the current operation states of the first and second
compressors (110, 120).
[0057] In a full (100%) operating state where all the first and
second compressors (110, 120) are operating currently, the control
unit (200) controls the expansion device driving unit (240) to
increase the amount of the refrigerant introduced through the
expansion device (140a) into the evaporator (150a) of the first
indoor unit that is in the overload state.
[0058] If only some of the first and second compressors (110, 120)
operate, the control unit (200) controls the compressor driving
unit (230) to increase a refrigerant compression capacity. That is,
if only the second compressor (120) of which a refrigerant
compression capacity may be about 40% of the total refrigerant
compression capacity of a system is operating currently, the
control unit (220) stops the operation of the second compressor
(120) and drives the first compressor (110) of which a refrigerant
compression capacity may be about 60% of the total refrigerant
compression capacity of the system to increase a refrigerant
compression capacity. If only the first compressor (110) of which a
refrigerant compression capacity is about 60% of the total
refrigerant compression capacity of the system is currently
operating, the control unit (220) operates all the first and second
compressors (110, 120) to increase a refrigerant compression
capacity to 100%.
[0059] After the refrigerant compression capacity is increased by
controlling the operations of the first and second compressors
(110, 120), the control unit (220) controls the expansion device
driving unit (240) to increase the amount of the refrigerant
introduced into the evaporator (150a) of the first indoor unit
through the expansion device (140a).
[0060] In this state, the control unit (220) determines whether the
overload state of the first indoor unit is removed, on the basis of
the temperature of the room with the first indoor unit installed
therein, which is detected by the temperature detecting unit (210).
If it is determined that the overload state of the first indoor
unit has not yet been removed, the control unit repeatedly performs
the process of determining whether the overload state of the first
indoor unit has been removed, while increasing the amount of the
refrigerant introduced into the first evaporator (150a).
[0061] If it is determined that the overload state of the first
indoor unit has been removed, the control unit (220) stops the
operation of the air conditioner in a partial overload state, and
then controls the operation of the air conditioner according to the
temperatures of the rooms with the indoor units installed therein,
which are detected by the temperature detecting units (210), so
that the air conditioner can operate in a normal state.
[0062] FIG. 3 is a flowchart illustrating a method for removing a
partial overload according to the present invention. Referring to
FIG. 3, when a command for operating the air conditioner is input,
e.g., through the user input unit (200) (which may be manipulated
by a user (S300)), the control unit (220) starts the operation of
the air conditioner (S302). That is, the control unit (220)
controls the compressor driving unit (230) according to the command
for operating the air conditioner so as to drive the first
compressor (110) or the second compressor (120), and controls the
expansion device driving unit (240) to adjust the opening/closing
amounts of the expansion devices (140a, 140b, . . . ), thereby
performing a cooling operation of the air conditioner.
[0063] Further, on the basis of an output signal of the temperature
detecting unit (210), the control unit (220) recognizes the
temperature of a room with each of the indoor units installed
therein (s304), and determines whether there is a first indoor unit
operating in an overload state, on the basis of the recognized room
temperature (S306).
[0064] If it is determined that a first indoor unit is operating in
an overload state, the control unit (220) determines whether the
first indoor unit has been operating in the overload state beyond a
predetermined period of time (S308).
[0065] If it is determined that the overload state continues beyond
the predetermined period of time, the control unit (200) determines
whether the plurality of second indoor units are also overloaded
(S310). That is, the control unit (220) determines whether the
other indoor units in addition to the first indoor unit are also
overloaded.
[0066] If it is determined that there is no first indoor unit
operating in the overload state, that the overload state of the
first indoor unit does not continue beyond the predetermined period
of time, or that the plurality of second indoor units in addition
to the first indoor unit are also operating in the overload state,
the control unit (220) recognizes that the air conditioner is
operating in the overload state as a whole. Then, the control unit
(220) controls the operation of the air conditioner according to
the temperature of a room with each of the indoor units installed
therein, which is detected by the temperature detecting unit (210),
so that the air conditioner can operate in a normal state
(S324).
[0067] If it is determined that the first indoor unit is operating
in the overload state beyond the predetermined period of time and
the plurality of second indoor units are not operating in the
overload state, the control unit (200) recognizes that the air
conditioner is operating in a partial overload state (S312).
[0068] Then, the control unit (220) determines whether the air
conditioner is operating in a full operating state where all the
first and second compressors (110, 120) are operating (S314) That
is, the control unit (220) determines whether all of the first
compressor (110) of which a refrigerant compression capacity is 60%
of the total refrigerant compression capacity of the system and the
second compressor (120) of which a refrigerant compression capacity
is 40% of the total refrigerant compression capacity of the system
are operating in a state where the compressor driving unit (230) is
controlled.
[0069] If it is determined that the air conditioner is operating in
the full (100%) operating state where all the first and second
compressors (110, 120) are operating currently, the control unit
(200) increases the amount of the refrigerant to be introduced into
the evaporator (150a) of the first indoor unit (S316). That is, the
control unit (200) controls the expansion device driving unit (240)
to increase the amount of the refrigerant introduced through the
expansion device (140a) into the evaporator (150a), thereby
enhancing the cooling capacity of the first indoor unit.
[0070] If it is determined that only some of the first and second
compressors (110, 120) are operating, the control unit (200)
controls the compressor driving unit (230) to increase a
refrigerant compression capacity (S318).
[0071] That is, if only the second compressor (120) of which the
refrigerant compression capacity is, e.g., about 40% of the total
refrigerant compression capacity of the system is operating
currently, the control unit (220) stops the operation of the second
compressor (120) and drives the first compressor (110) of which the
refrigerant compression capacity is 60% of the total refrigerant
compression capacity of the system to increase a refrigerant
compression capacity. On the contrary, if only the first compressor
(110) of which the refrigerant compression capacity is, e.g., about
60% of the total refrigerant compression capacity of the system is
operating currently, the control unit (220) operates all the first
and second compressors (110, 120) to increase a refrigerant
compression capacity to 100%.
[0072] After a refrigerant compression capacity is increased by
controlling the operations of the first and second compressors
(110, 120), the control unit (220) controls the expansion device
driving unit (240) to increase the amount of the refrigerant
introduced into the evaporator (150a) of the first indoor unit
through the expansion device (140a) (S320).
[0073] In this state, the control unit (220) determines whether the
overload state of the first indoor unit has been removed, on the
basis of the detection signal of the temperature detecting unit
(210) (S322).
[0074] If it is determined that the overload state of the first
indoor unit has not yet been removed, the control unit (220)
returns to step S314 to repeatedly perform the processes of
increasing the amount of the refrigerant introduced into the first
evaporator (150a) and determining whether the overload state of the
first indoor unit has been removed.
[0075] If it is determined in step S322 that the overload state of
the first indoor unit has been removed, the control unit (220)
stops the operation of the air conditioner in a partial overload
state and then controls the air conditioner according to the
temperature of a room with each of the indoor units installed
therein, which is detected by the temperature detecting unit (210),
so that the air conditioner is operating in a normal state
(S324).
[0076] According to the present invention, the temperature of
indoor air may be detected by, e.g., the temperature sensor
installed in each of indoor units, and a first indoor unit
operating in an overload state due to an increased cooling load may
be detected based on the detected temperature of indoor air. Then,
the cooling capacity of the first indoor unit that is detected may
be increased by increasing the amount of a refrigerant introduced
into an evaporator of the first indoor unit, thereby removing the
overload state of the first indoor unit.
[0077] If a plurality of compressors are provided, the amount of
the refrigerant introduced into the evaporator of the first indoor
unit may be increased so that the refrigerant compression
capacities of the compressors is, e.g., increased simultaneously.
Accordingly, without lowering the cooling capacities of second
indoor units of which cooling loads are constantly maintained, a
room with the first indoor unit installed therein can be cooled
rapidly by increasing only the amount of the refrigerant to be
introduced into the first indoor unit having an increased cooling
load, and thus, the overload state can be removed.
[0078] It is further noted that the foregoing examples have been
provided merely for the purpose of explanation and are in no way to
be construed as limiting of the present invention. While the
present invention has been described with reference to a preferred
embodiment, it is understood that the words which have been used
herein are words of description and illustration, rather than words
of limitation. Changes may be made, within the purview of the
appended claims, as presently stated and as amended, without
departing from the scope and spirit of the present invention in its
aspects. Although the present invention has been described herein
with reference to particular means, materials and embodiments, the
present invention is not intended to be limited to the particulars
disclosed herein; rather, the present invention extends to all
functionally equivalent structures, methods and uses, such as are
within the scope of the appended claims.
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