U.S. patent application number 11/552403 was filed with the patent office on 2007-05-03 for apparatus and method for controlling multi-type air conditioner.
This patent application is currently assigned to LG ELECTRONICS INC.. Invention is credited to Se Yoon HO, Jeong Taek PARK, Chan Ho SONG.
Application Number | 20070095084 11/552403 |
Document ID | / |
Family ID | 37965241 |
Filed Date | 2007-05-03 |
United States Patent
Application |
20070095084 |
Kind Code |
A1 |
PARK; Jeong Taek ; et
al. |
May 3, 2007 |
APPARATUS AND METHOD FOR CONTROLLING MULTI-TYPE AIR CONDITIONER
Abstract
A method for controlling a multi-type air conditioner, includes
selecting, from among a plurality of indoor units connected to an
outdoor unit, at least one currently operating indoor unit;
determining whether the at least one currently operating indoor
unit is in an overcooling state; selecting, from among the
plurality of indoor units connected to the outdoor unit, at least
one currently stopped indoor unit. Further, if it is determined
that the at least one currently operating indoor unit is operating
in the overcooling state the refrigerant bypasses the at least one
currently operating indoor unit such that refrigerant discharged
from the outdoor unit is introduced into the at least one currently
stopped indoor unit.
Inventors: |
PARK; Jeong Taek;
(Gyeonggi-do, KR) ; SONG; Chan Ho; (Gyeonggi-do,
KR) ; HO; Se Yoon; (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: |
37965241 |
Appl. No.: |
11/552403 |
Filed: |
October 24, 2006 |
Current U.S.
Class: |
62/197 ;
62/198 |
Current CPC
Class: |
F25B 2400/0751 20130101;
F25B 5/02 20130101; F25B 2700/2104 20130101; F24F 11/83
20180101 |
Class at
Publication: |
062/197 ;
062/198 |
International
Class: |
F25B 41/00 20060101
F25B041/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 28, 2005 |
KR |
10-2005-0102170 |
Claims
1. A method for controlling a multi-type air conditioner,
comprising: selecting, from among a plurality of indoor units
connected to an outdoor unit, at least one currently operating
indoor unit; determining whether the at least one currently
operating indoor unit is in an overcooling state; selecting, from
among the plurality of indoor units connected to the outdoor unit,
at least one currently stopped indoor unit; and bypassing the at
least one currently operating indoor unit such that refrigerant
discharged from the outdoor unit is introduced into the at least
one currently stopped indoor unit, when it is determined that the
at least one currently operating indoor unit is operating in the
overcooling state.
2. The method as claimed in claim 1, further comprising: operating
the at least one currently operating indoor unit in response to an
operation command inputted from a command input unit.
3. The method as claimed in claim 1, wherein determining whether
the at least one currently operating indoor unit is operating in
the overcooling state comprises: selecting a preset temperature of
the at least one currently operating indoor unit; detecting a
detected temperature via a temperature sensor; comparing the preset
temperature with the detected temperature; and determining that the
at least one currently operating indoor unit is operating in the
overcooling state, when the detected temperature is less than the
preset temperature.
4. The method as claimed in claim 1, wherein the at least one
currently operating indoor unit is a plurality of currently
operating indoor units.
5. The method as claimed in claim 3, wherein the at least one
currently operating indoor unit is a plurality of currently
operating indoor units.
6. The method as claimed in claim 5, further comprising: providing
each of the plurality of currently operating indoor units with
respective temperature sensors.
7. The method as claimed in claim 1, further comprising: prior to
bypassing the refrigerant to the at least one stopped indoor unit,
determining a refrigerant compression capacity of the outdoor unit,
and reducing the refrigerant compression capacity of the outdoor
unit when the determined refrigerant compression capacity is
greater than a minimum refrigerant compression capacity.
8. The method as claimed in claim 1, further comprising: operating
the at least one currently operating indoor unit by opening a
solenoid valve; and providing an expander in the at least one
currently operating indoor unit such that the refrigerant
discharged from the outdoor unit is introduced into an evaporator,
and an evaporating fan is driven to perform heat exchange between
the refrigerant and air while in the evaporator.
9. The method as claimed in claim 1, wherein the refrigerant
bypasses at least two currently operating indoor units such that
the refrigerant is introduced into at least two currently stopped
indoor units.
10. The method as claimed in claim 1, further comprising: selecting
the at least one currently stopped indoor unit having a solenoid
valve, an expander, an evaporator, and an evaporating fan; opening
the solenoid valve such that the refrigerant discharged from the
outdoor unit bypasses the at least one currently operating indoor
unit such that the refrigerant is introduced into an evaporator;
and preventing an operation of the evaporating fan.
11. An apparatus for controlling a multi-type air conditioner,
comprising: a controller that selects, from among a plurality of
indoor units connected to an outdoor unit, at least one currently
operating indoor unit; wherein the controller determines whether
the at least one currently operating indoor unit is in an
overcooling state; wherein the controller selects, from among the
plurality of indoor units connected to the outdoor unit, at least
one currently stopped indoor unit; and wherein when the controller
determines that the at least one currently operating indoor unit is
operating in the overcooling state, the refrigerant discharged from
the outdoor unit bypassing the at least one currently operating
indoor unit, and is introduced into the at least one currently
stopped indoor unit.
12. The apparatus according to claim 11, further comprising: a
command input unit that operates the at least one currently
operating indoor unit in response to an operation command inputted
by a user.
13. The apparatus according to claim 11, wherein the controller
selects a preset temperature of the at least one currently
operating indoor unit, and compares the preset temperature with a
detected temperature detected by a temperature sensor, and wherein
when the detected temperature is less than the preset temperature,
the controller determines that the at least one currently operating
indoor unit is operating in the overcooling state.
14. The apparatus according to claim 11, wherein the at least one
currently operating indoor unit is a plurality of currently
operating indoor units.
15. The apparatus according to claim 13, wherein the at least one
currently operating indoor unit is a plurality of currently
operating indoor units.
16. The method as claimed in claim 5, further comprising: providing
each of the plurality of currently operating indoor units with
respective temperature sensors.
17. The apparatus according to claim 11, wherein, prior to
bypassing the refrigerant to the at least one stopped indoor unit,
the controller determines a refrigerant compression capacity of the
outdoor unit, and wherein when the controller determines that the
refrigerant compression capacity is greater than a minimum
refrigerant compression capacity, the refrigerant compression
capacity of the outdoor unit is reduced.
18. The apparatus according to claim 11, further comprising: a
solenoid valve that opens to operate the at least one currently
operating indoor unit; an expander provided in the at least one
currently operating indoor unit, and configured to allow
refrigerant discharged from the outdoor unit to be introduced into
an evaporator; and an evaporating fan driven to perform heat
exchange between the refrigerant and air while in the
evaporator.
19. The apparatus according to claim 11, wherein the refrigerant
bypasses at least two currently operating indoor units such that
the refrigerant is introduced into at least two currently stopped
indoor units.
20. The apparatus according to claim 11, wherein the at least one
currently stopped indoor unit includes a solenoid valve, an
expander, an evaporator, and an evaporating fan; wherein the
solenoid valve, when opened, is configured to allow the refrigerant
discharged from the outdoor unit to bypass the at least one
currently operating indoor unit such that the refrigerant is
introduced into an evaporator; and wherein an operation of the
evaporating fan is prevented.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. .sctn.119
to Korean Patent Application No. 10-20050102170 filed on Oct. 28,
2005, the entirety of which is hereby incorporated by
reference.
BACKGROUND
[0002] The present invention relates to a method for controlling a
multi-type air conditioner.
[0003] In general, an air conditioner withdraws hot air from a room
and the hot air is heat exchanged at an evaporator in a cooling
cycle. Cool air generated by the heat exchange is discharged into
the room, and repeated operation thereof cools the room.
[0004] The cooling cycle typically 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 for conversion 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 cooling cycle including a closed circuit having
a compressor, a condenser, an expansion device and an evaporator
repeatedly performs a compression, condensation, expansion and
evaporation of a refrigerant. The cooling cycle carries out the
heat exchange of indoor air with the refrigerant evaporated in the
evaporator to generate cool air and then discharges the generated
cool air into the room so that the room can be cooled.
[0009] In an air conditioner provided with such a cooling cycle,
the compressor generates much noise when operating, and the
condenser is provided with an additional condensing fan to
dissipate heat generated from the condenser. Accordingly, the
compressor, the condenser and the condensing fan are provided in an
outdoor unit.
[0010] Noise is scarcely generated in the expansion device and an
additional evaporating fan is provided in the evaporator for
generating cool air through heat exchange with indoor air. The
evaporation fan generates very little noise. Thus, the expansion
device, the evaporator and the evaporating fan are provided in an
indoor unit.
[0011] The indoor and outdoor units are connected to each other
through a connecting pipe, so that the refrigerant supplied from
the condenser of the outdoor unit can be introduced into the
evaporator through the connecting pipe and the expansion device of
the indoor unit and the refrigerant discharged from the evaporator
can be introduced into the compressor through the connecting
pipe.
[0012] Generally, one indoor unit in such an air conditioner is
connected to an outdoor unit. Recently, in order to improve energy
consumption efficiency, a multi-type air conditioner has been
widely used, wherein a plurality of indoor units are connected to
an outdoor unit and can be selectively operated to selectively cool
a plurality of rooms.
[0013] In the multi-type air conditioner, the outdoor unit is
generally provided with two compressors for supplying sufficient
liquid refrigerant of high temperature and pressure to a plurality
of indoor units. A gas refrigerant of high temperature and pressure
generated through compression by the two compressors is condensed
into a liquid refrigerant of high temperature and pressure by a
condenser and then supplied to the plurality of indoor units.
[0014] Here, the compression capacities of the two compressors may
be identically set. For example, each of the first compressor and
the second compressor has a 50% refrigerant compression capacity of
a total refrigerant compression capacity of 100%.
[0015] On the other hand, the compression capacities of the two
compressors provided in the outdoor unit may be differently set
from each other. For example, the first compressor may have a 40%
refrigerant compression capacity of the total refrigerant
compression capacity while the second compressor may have a 60%
refrigerant compression capacity of the total refrigerant
compression capacity.
[0016] Each of the plurality of indoor units includes a solenoid
valve for passing or blocking the liquid refrigerant of high
temperature and pressure; an expansion device for expanding the
liquid refrigerant of high temperature and pressure, which has
passed through the solenoid valve, into a liquid refrigerant of low
temperature and pressure; and an evaporator for performing heat
exchange of the liquid refrigerant, which has been expanded in the
expansion device, with outdoor air to generate cold air and to
convert the liquid refrigerant into a gas refrigerant of low
temperature and pressure.
[0017] In the multi-type air conditioner, if only some of the
indoor units connected to the outdoor unit are to be operated,
there may occur a case where the minimum refrigerant compression
capacity of the compressors is larger than the cooling capacity of
the evaporators provided in the indoor units in operation.
[0018] If the minimum refrigerant compression capacity of the
compressors is larger than the cooling capacity of the evaporators
provided in the indoor units in operation, there may occur a case
where the indoor units are operated in an overcooling state and
indoor temperature is lower than a preset temperature, thereby
causing a user to feel a chill, which in some cases may be
detrimental to a user's health.
[0019] In order to prevent the indoor units from operating in the
overcooling state, the conventional multi-type air conditioner is
configured such that the gas refrigerant of high temperature and
pressure discharged from the compressor is not introduced into the
condenser but is expanded and converted, by the expansion device,
into the gas refrigerant of low temperature and pressure that in
turn is bypassed to an accumulator or a suction side of the
compressor.
[0020] However, the conventional air conditioner is often provided
with an additional solenoid valve and expansion device for
bypassing the gas refrigerant of high temperature and pressure
discharged from the compressor.
SUMMARY
[0021] Accordingly, an object of the present invention is to
provide a method for controlling a multi-type air conditioner
having one outdoor unit and a plurality of indoor units, wherein a
refrigerant supplied from the outdoor unit is efficiently bypassed
to prevent an overcooling operation without the need for an
additional solenoid valve and expansion device.
[0022] Another object of the present invention is to provide a
method for controlling a multi-type air conditioner, wherein it is
determined whether an operating indoor unit is operated in an
overcooling state, based on a preset temperature of the indoor unit
and an indoor temperature, and if the indoor unit is operating in
an overcooling state, a refrigerant is bypassed to a currently
inoperative indoor unit to thereby reduce the amount of the
refrigerant introduced into the operating indoor unit and to
prevent the overcooling operation of the indoor unit.
[0023] According to a control method of the present invention for
achieving the above objects, if a user manipulates a key disposed
at a predetermined indoor unit to give off an operation command, in
response, the relevant indoor unit generates the operation command
and outputs it to a control unit. The control unit determines which
indoor unit has generated the operation command. The indoor unit
and the outdoor unit are operated in response to the operation
command, while a refrigerant discharged from the outdoor unit is
supplied to the indoor unit which has generated the operation
command.
[0024] The control unit determines whether the indoor unit is
operating in an overcooling state, based on a preset temperature
for the operating indoor unit and indoor temperature detected by
the operating indoor unit.
[0025] For example, the overcooling operation of the indoor unit is
determined if the preset temperature for the indoor unit is below
the temperature of indoor air.
[0026] If the control unit determines that the indoor unit is
operating in the overcooling state, the control unit selects an
indoor unit which is not in operation among the plurality of indoor
units connected to the outdoor unit, and bypasses some of the
refrigerant discharged from the outdoor unit to the selected indoor
unit. That is, the control unit may select an indoor unit (from
among the plurality of indoor units) which is currently
stopped.
[0027] The control method of the present invention includes a
control unit supplying a refrigerant discharged from an outdoor
unit to at least one first indoor unit currently operating among a
plurality of indoor units connected to the outdoor unit;
determining whether the first indoor unit (e.g., at least one
currently operating indoor units) is currently operating in an
overcooling state; and bypassing the refrigerant discharged from
the outdoor unit to at least one second indoor unit (e.g., that is
at least one currently stopped indoor unit) which is not currently
in operation if it is determined that the first indoor unit is
operating in the overcooling state.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] 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:
[0029] FIG. 1 is a view showing the configuration of a
refrigeration cycle of an air conditioner to which a control method
of the present invention is applied;
[0030] FIG. 2 is a block diagram of the air conditioner to which
the control method of the present invention is applied; and
[0031] FIG. 3 is a flowchart illustrating the control method of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0032] 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:
[0033] FIG. 1 is a view showing the configuration of a
refrigeration cycle of an air conditioner to which a control method
of the present invention is applied. Here, reference numeral "100"
designates an outdoor unit, and reference numerals "110-1",
"110-2", . . . "110-N" designate a first indoor unit to a N-th
indoor unit connected to the outdoor unit (100).
[0034] The outdoor unit (100) includes an accumulator (101), first
and second compressors (103, 103a), back-flow preventers or
preventing means (105, 105a), a condenser (107) and a condensing
fan (109).
[0035] The accumulator (101) stores a gas refrigerant of low
temperature and pressure discharged from the first to N-th indoor
units (110-1, 110-2, . . . , 110-N) and supplies the stored gas
refrigerant of low temperature and pressure to the first and second
compressors (103, 103a). Further, the accumulator (101) prevents a
liquid refrigerant from being supplied to the first and second
compressors (103, 103a).* The first and second compressors (103,
103a) withdraws the gas refrigerant of low temperature and pressure
stored in the accumulator (101) and then converts it into a gas
refrigerant of high temperature and pressure.
[0036] Here, for example, the first compressor (103) has a 40%
refrigerant compression capacity out of the total refrigerant
compression capacity of a system, and the second compressor (103a)
has a 60% refrigerant compression capacity of the total refrigerant
compression capacity.
[0037] The back-flow preventers or preventing means (105, 105a)
prevents the gas refrigerant of high temperature and pressure
compressed in the first and second compressors (103, 103a) from
flowing backward. For example, check valves may be used as the
back-flow preventing means (105, 105a) to prevent backflow of the
refrigerant.
[0038] The condenser (107) condenses the gas refrigerant of high
temperature and pressure, which has been compressed in the first
and second compressors (103, 103a) and which has passed through the
back-flow preventing means (105, 105a), into the liquid refrigerant
of high temperature and pressure for supply to the first to the
N-th indoor units (110-1, 110-2, . . . , 110-N).
[0039] The condensing fan (109) dissipates heat thus generated when
the condenser (107) condenses the gas refrigerant of high
temperature and pressure into the liquid refrigerant of high
temperature and pressure.
[0040] The first to the N-th indoor units (110-1, 110-2, 110-N) are
provided with solenoid valves (111-1, 111-2, . . . , 111-N),
expansion devices (113-1, 113-2, . . . , 113-N), evaporators
(115-1, 115-2, . . . , 115-N), evaporating fans (117-1, 117-2, . .
. , 117-N) and temperature sensors (119-1, 119-2, . . . , 119-N),
respectively.
[0041] The solenoid valves (111-1, 111-2, . . . , 111-N) pass or
block the liquid refrigerant of high temperature and pressure that
has been condensed in the condenser (107).
[0042] The expansion devices (113-1, 113-2, . . . , 113-N) expand
the liquid refrigerant of high temperature and pressure, which has
passed through the solenoid valves (111-1, 111-2, 111-N), such that
the liquid refrigerant of high temperature and pressure is
converted into a liquid refrigerant of low temperature and
pressure.
[0043] The evaporators (115-1, 115-2, . . . , 115-N) perform heat
exchange of the liquid refrigerant of low temperature and pressure,
which has been expanded in the expansion devices (113-1, 113-2, . .
. , 113-N) with indoor air to generate cool air while converting
the liquid refrigerant into a gas refrigerant of low temperature
and pressure. Further, the gas refrigerant of low temperature and
pressure is introduced into the accumulator (101) of the outdoor
unit (100).
[0044] The evaporating fans (117-1, 117-2, . . . , 117-N) withdraw
the indoor air so that the indoor air can be subjected to heat
exchange in the evaporators (115-1, 115-2, . . . , 115-N) to
generate cold air, and then discharge the generated cold air into
rooms.
[0045] The temperature sensors (119-1, 119-2, . . . , 119-N) detect
the temperature of indoor air withdrawn when the evaporating fans
(117-1, 117-2, . . . , 117-N) are driven.
[0046] FIG. 2 is a block diagram of the air conditioner to which
the control method of the present invention is applied. Here,
reference numeral "200" designates a control unit. The control unit
(200) controls a cooling operation of the air conditioner in
response to a user's operation command.
[0047] According to the control method of the present invention,
the control unit (200) determines whether an indoor unit is
operating in an overcooling state, on the basis of the temperature
of indoor air and a user's preset temperature for the operating
indoor unit. If it is determined that the indoor unit is operating
in the overcooling state, the control unit bypasses the refrigerant
to an indoor unit, which is not in operation, to prevent the
overcooling operation of the operating indoor unit. For example,
assuming that the indoor unit (110-1) performs a cooling operation
and other indoor units (110-2, . . . , 110-N) are not in operation,
the control unit (200) determines whether the indoor unit is
operating in the overcooling state, on the basis of the temperature
of indoor air and a user's preset temperature for the operating
indoor unit (110-1) If it is determined that the indoor unit is
operating in the overcooling state, the control unit makes bypasses
the refrigerant to the indoor units (110-2, . . . , 110-N), which
are not in operation, to prevent the overcooling operation of the
operating indoor unit (110-1).
[0048] Reference numeral "210" designates a compressor driving
unit. The compressor driving unit (210) selectively drives the
first compressor (103) or the second compressor (103a) under the
control of the control unit (200), thereby compressing the
refrigerant.
[0049] Reference numeral "220" designates a condensing fan driving
unit. The condensing fan driving unit (220) drives the condensing
fan (109) under the control of the control unit (200), thereby
cooling the condenser (107).
[0050] Reference numeral "230" designates a command input unit. The
command input unit (230) includes a plurality of function keys
provided on the indoor units (110-1, 110-2, . . . , 110-N). As a
user manipulates the function keys to generate a user's command
such as an operation command for the air conditioner and a preset
temperature signal, the command input unit (230) transmits the
command to the control unit (200).
[0051] Reference numeral "240" designates a temperature detecting
unit. The temperature detecting unit (240) includes the temperature
sensors (119-1, 119-2, . . . , 119-N) provided in the indoor units
(110-1, 110-2, . . . , 110-N), respectively. The temperature
detecting unit detects the temperature of indoor air and transmits
the detected temperature to the control unit (200).
[0052] Reference numeral "250" designates a solenoid valve driving
unit. The solenoid valve driving unit (250) selectively drives the
solenoid valves (111-1, 111-2, . . . , 111-N) provided in the first
to N-th indoor units (110-1, 110-2, . . . , 110-N) under the
control of the control unit (200), thereby passing or blocking the
refrigerant condensed in the condenser (107).
[0053] Reference numeral "260" designates an expansion device
driving unit. The expansion device driving unit (260) selectively
drives the expansion devices (113-1, 113-2, . . . , 113-N) provided
in the first to N-th indoor units (110-1, 110-2, . . . , 110-N)
under the control of the control unit (200), thereby expanding the
refrigerant that has passed through the solenoid valves (111-1,
111-2, . . . , 111-N).
[0054] Reference numeral "270" designates an evaporating fan
driving unit The evaporating fan driving unit (270) selectively
drives the evaporating fans (117-1, 117-2, . . . , 117-N) provided
at the first to N-th indoor units (110-1, 110-2, . . . , 110-N)
under the control of the control unit (200), thereby withdrawing
indoor air and performing heat exchange for the withdrawn air in
the evaporators (115-1, 115-2, . . . , 115-N) and discharging cold
air into rooms.
[0055] In the air conditioner thus constructed as above, if a user
manipulates the function keys provided on the first to N-th indoor
units (110-1, 110-2, . . . , 110-N) in order to instruct the air
conditioner to operate, the command inputting unit (230) generates
an operation command for the air conditioner.
[0056] Here, assume that the user manipulates the function keys on
the first indoor unit (110-1) to instruct the air conditioner to
operate.
[0057] If the command inputting unit (230) generates an operation
command for the first indoor unit (110-1), the control unit (200)
begins to operate the air conditioner. That is, the control unit
(200) controls the compressor driving unit (210) to drive the
compressors (103, 103a) provided in the outdoor unit (100) and also
controls the condensing fan driving unit (220) to cool the
condenser (107).
[0058] Moreover, the control unit (200) determines the status of
the first indoor unit (110-1), which is instructed to operate, and
performs control such that the first indoor unit (110-1) is to
operate. That is, the control unit (200) controls the solenoid
valve driving unit (250) and the expansion device driving unit
(260) to supply the refrigerant to the evaporator (115-1) of the
first indoor unit (110-1) and also controls the evaporating fan
driving unit (270) to drive the evaporating fan (117-1) and to
evaporate the refrigerant in the evaporator (115-1).
[0059] In such a state, the control unit (200) determines the
indoor temperature of a room with the first indoor unit (110-1)
installed therein, which is detected by the temperature detecting
unit (240), and a preset temperature set by user' manipulation on
the function keys provided on the first indoor unit (110-1). If it
is determined that the indoor temperature is below the preset
temperature, the control unit (200) determines that the first
indoor unit (110-1) is operating in the overcooling state.
[0060] If it is determined that the first indoor unit (e.g., at
least one currently operating indoor unit) is operating in the
overcooling state, the control unit (200) determines whether the
compressors (103, 103a) are operating with the minimum refrigerant
compression capacity. If the compressors (103, 103a) are not
operating with the minimum refrigerant compression capacity, the
control unit (200) controls the operations of the first and second
compressors (103, 103a) through the compressor driving unit (210)
to reduce the refrigerant compression capacity (S312).
[0061] If it is determined that the first indoor unit (110-1)
continues to operate in the overcooling state even though the first
and second compressors (103, 103a) are driven with the minimum
refrigerant compression capacity, the control unit (200) selects
one indoor unit to which the refrigerant is not bypassed among the
second to N-th indoor units (110-2, . . . , 110-N) which are not
currently in operation (S316). For example, the control unit
selects the second indoor unit (at least one currently stopped
indoor unit_) (110-2) as an indoor unit to which the refrigerant is
to be bypassed.
[0062] Once the second indoor unit (110-2) is selected to bypass
the refrigerant thereto, the control unit (200) controls the
selected solenoid valve driving unit (250) and the expansion device
driving unit (260) to bypass the refrigerant to the evaporator
(115-2) of the second indoor unit (110-2).
[0063] If the first indoor unit (110-1) continues to operate in the
overcooling state even though the refrigerant is bypassed to the
second indoor unit (110-2), the control unit (200) sequentially
selects the third to N-th indoor units (110-3, . . . , 110-N) to
bypass the refrigerant thereto.
[0064] Accordingly, it is possible to prevent the overcooling
operation of the first indoor unit (110-1) that is operating
currently.
[0065] At this time, the control unit (200) does not drive the
evaporating fans (117-2, . . . , 117-N) provided in the second to
N-th indoor units (110-2, . . . , 110-N) to which the refrigerant
is bypassed, so that the refrigerant cannot be subjected to heat
exchange with indoor air in the evaporators (115-2, . . . , 115-N)
of the second to N-th indoor units (110-2, . . . , 110-N).
[0066] Referring now to FIG. 3, if the user manipulates the
function keys provided on the first indoor unit (110-1) or the
second to N-th indoor units (110-2, . . . , 110-N) to instruct the
air conditioner to operate, the command inputting unit (230)
generates an operation command for the air conditioner in response
to the user's manipulation on the function keys, and the generated
operation command is inputted into the control unit (200)
(S300).
[0067] To this end, the control unit (200) determines whether an
indoor unit, which is instructed to operate, is the first indoor
unit (110-1) or the second to N-th indoor units (110-2, . . . ,
110-N) (S302).
[0068] Here, assume that the user manipulates the first indoor unit
(110-1) so that the first indoor unit can operate, and all the
second to N-th indoor units (110-2, . . . , 110-N) are not in
operation.
[0069] When the control unit determines that the first indoor unit
(110-1) is instructed to operate, the control unit (200) performs
the operation of the air conditioner (S304).
[0070] In other words, the control unit (200) controls the
compressor driving unit (210) to drive the first compressor (103)
or the second compressor (103a) provided in the outdoor unit (100)
so that the refrigerant can be compressed. Further, the control
unit (200) controls the condensing fan driving unit (220) to drive
the condensing fan (109) provided in the outdoor unit (100) so that
heat generated in the condenser (107) can be dissipated.
[0071] Further, the control unit (200) operates the first indoor
unit (110-1). That is, the control unit (200) controls the solenoid
valve driving unit (250) to open the solenoid valve (111-1)
provided in the first indoor unit (110-1) and controls the
expansion device driving unit (260) to cause the solenoid valve
(111-1) to expand the refrigerant. Moreover, the control unit
controls the evaporating fan driving unit (270) to drive the
evaporating fan (117-1) and to perform heat exchange of the
refrigerant with indoor air in the evaporator (115-1).
[0072] When the air conditioner is operating in this way, the
control unit (200) determines the temperature of the room with the
first indoor unit (110-1) installed therein on the basis of a
detection signal of the temperature sensor (119-1) of the
temperature detecting unit (240) provided in the first indoor unit
(110-1). Furthermore, the control unit (200) makes the
determination by receiving, through the command input unit (230), a
preset temperature set by user's manipulation on the function keys
provided on the first indoor unit (110-1) (S306).
[0073] The control unit (200) compares the indoor temperature with
the preset temperature to determine whether the indoor temperature
is below the preset temperature (S308).
[0074] If it is determined that the indoor temperature is not below
the preset temperature, the control unit (200) determines that the
first indoor unit (110-1) is not operating in the overcooling
state. Then, the control unit repeats the determination on the
indoor temperature and the preset temperature (S306) and the
determination on whether the indoor temperature is below the preset
temperature (S308).
[0075] On the contrary, if the indoor temperature is below than the
preset temperature, the control unit (200) determines that the
first indoor unit (110-1) is operating in the overcooling state and
then determines whether the compressor is operating with the
minimum refrigerant compression capacity (S310).
[0076] That is, the control unit (200) determines whether only the
first compressor (103) with a 40% refrigerant compression capacity
is operating.
[0077] If it is determined that the compressor is not operating
with the minimum refrigerant compression capacity, the control unit
(200) controls the operations of the first and second compressors
(103, 103a) through the compressor driving unit (210) to reduce the
refrigerant compression capacity (S312).
[0078] To be more specific, if all the first and second compressors
(103, 103a) are operated to ensure a 100% refrigerant compression
capacity, the control unit stops the operation of the first
compressor (103) and maintains the operation of only the second
compressor (103a) to reduce the refrigerant compression capacity to
60% of the total refrigerant compression capacity.
[0079] If only the second compressor (103a) is operated to ensure
the 60% refrigerant compression capacity, the control unit stops
the operation of the second compressor (103a) and operates the
first compressor (103) to reduce the refrigerant compression
capacity to 40% of the total refrigerant compression capacity.
[0080] Then, the control unit is put on standby for a predetermined
period of time (S314) and returns to step S306 where it makes
determination on indoor temperature and the preset temperature. The
control unit repeats the step of determining whether the indoor
temperature is below the preset temperature.
[0081] If it is determined in step S310 that the compressor is
operating with the minimum refrigerant compression capacity, the
control unit (200) selects one indoor unit to which the refrigerant
is not bypassed among the second to N-th indoor units (110-2, . . .
, 110-N) that are not currently in operation (S316). For example,
the control unit selects the second indoor unit (110-2) as an
indoor unit to which the refrigerant is bypassed.
[0082] Once the second indoor unit (110-2) is selected as an indoor
unit to which the refrigerant is bypassed, the control unit
bypasses the refrigerant to the selected second indoor unit (110-2)
(S318) and reduces the amount of the refrigerant introduced into
the first indoor unit (110-1), thereby preventing the overcooling
operation of the first indoor unit (110-1).
[0083] That is, the control unit (200) controls the solenoid valve
driving unit (250) to open the solenoid valve (113-2) provided in
the second outdoor unit (110-2) and controls the expansion device
driving unit (260) to open the expansion device (115-2) provided in
the second outdoor unit (110-2).
[0084] Successively, some of the refrigerant supplied from the
condenser (107) is supplied to the evaporator (115-2) through the
solenoid valve (113-2) and the expansion device (115-2) of the
second indoor unit (110-2), and the amount of the refrigerant
supplied to the evaporator (115-1) of the first indoor unit (110-1)
is reduced to prevent the overcooling operation of the first indoor
unit (110-1).
[0085] At this time, the control unit (200) does not drive the
evaporating fan (117-2) provided in the second indoor unit (110-2)
so that the refrigerant cannot be subjected to heat exchange with
indoor air in the evaporator (115-2) of the second indoor unit
(110-2), whereby a corresponding room is not cooled.
[0086] According to the present invention, in a multi-type air
conditioner having a plurality of indoor units connected to an
outdoor unit, if the cooling capacity of an indoor unit which is
currently operating is lower than the refrigerant compression
capacity of the compressor, a refrigerant is bypassed to an indoor
unit which is not in operation.
[0087] Therefore, according to the present invention, there is no
need for an additional solenoid valve and expansion device for
bypassing a refrigerant supplied from a condenser, resulting in
reduction of production costs. It is also possible to reduce the
amount of the refrigerant supplied to an operating indoor unit,
thereby preventing an overcooling operation.
[0088] Further, since evaporating fans provided in indoor units to
which a refrigerant is bypassed are not driven in the present
invention, heat exchange does not occur between indoor air and the
refrigerant in evaporators of the indoor units to which the
refrigerant is by passed. Therefore, rooms in which the indoor
units to which the refrigerant is bypassed are installed are not
cooled.
[0089] Although the present invention has been described and
illustrated in connection with the preferred embodiment, it will be
readily understood by those skilled in the art that various changes
and modifications can be made thereto without departing from the
spirit and scope of the present invention defined by the appended
claims.
[0090] For example, in a state where only one of a plurality of
indoor units is operating, and if two or more indoor units are
intended to be operated, the control unit determines whether all
indoor temperature detected by temperature sensors of the plurality
of indoor units which are operating is below a preset temperature.
If it is determined that all the indoor temperature detected by the
temperature sensors are below the preset temperature, the control
unit can select an indoor unit which is not in operation and
bypasses a refrigerant to the selected indoor unit.
[0091] 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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