U.S. patent application number 11/727870 was filed with the patent office on 2008-04-24 for simultaneous cooling-heating multiple type air conditioner.
Invention is credited to Ju Sang Kim.
Application Number | 20080092572 11/727870 |
Document ID | / |
Family ID | 39226677 |
Filed Date | 2008-04-24 |
United States Patent
Application |
20080092572 |
Kind Code |
A1 |
Kim; Ju Sang |
April 24, 2008 |
Simultaneous cooling-heating multiple type air conditioner
Abstract
A simultaneous cooling-heating multiple type air conditioner
includes a plurality of cooling-heating combined-use indoor units
controlled in an operation domain divided into a plurality of
operation zones based on a refrigerant suction pressure and a
refrigerant discharge pressure of a compressor. The operation
domain includes three operation zones. In the first operation zone,
a cooling-initiative simultaneous cooling and heating operation
mode is switched to a heating-initiative simultaneous cooling and
heating operation mode. In the second operation zone, the
cooling-initiative simultaneous cooling and heating operation mode
or the heating-initiative simultaneous cooling and heating
operation mode, does not switch to different modes. In the third
operation zone, the heating-initiative simultaneous cooling and
heating operation mode is switched to the cooling-initiative
simultaneous cooling and heating operation mode.
Inventors: |
Kim; Ju Sang; (Busan-si,
KR) |
Correspondence
Address: |
MCKENNA LONG & ALDRIDGE LLP;Song K. Jung
1900 K Street, N.W.
Washington
DC
20006
US
|
Family ID: |
39226677 |
Appl. No.: |
11/727870 |
Filed: |
March 28, 2007 |
Current U.S.
Class: |
62/160 |
Current CPC
Class: |
F25B 2313/007 20130101;
F25B 2313/02741 20130101; F25B 2313/0231 20130101; F25B 13/00
20130101 |
Class at
Publication: |
62/160 |
International
Class: |
F25B 13/00 20060101
F25B013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 19, 2006 |
KR |
10-2006-0101754 |
Claims
1. A simultaneous cooling-heating multiple type air conditioner
including a plurality of cooling-heating combined-use indoor units
and operating in an operation domain having a plurality of
operation zones divided by a refrigerant suction pressure and a
refrigerant discharge pressure of a compressor, wherein the
operation domain comprises: a first operation zone in which a
cooling-initiative simultaneous cooling and heating operation mode
is switched to a heating-initiative simultaneous cooling and
heating operation mode; a second operation zone in which the
cooling-initiative simultaneous cooling and heating operation mode
or the heating-initiative simultaneous cooling and heating
operation mode is not switched to different modes; and a third
operation zone in which the heating-initiative simultaneous cooling
and heating operation mode is switched to the cooling-initiative
simultaneous cooling and heating operation mode.
2. The simultaneous cooling-heating multiple type air conditioner
according to claim 1, wherein when operating in the first operation
zone, a suction pressure of the compressor is less than a first
suction pressure and a discharge pressure of the compressor is less
than a first discharge pressure, when operating in the second
operation zone, the suction pressure of the compressor is in a
range from the first suction pressure to a second suction pressure,
wherein the second suction pressure is greater than a first suction
pressure, and the discharge pressure of the compressor is in a
range from the first discharge pressure to a second discharge
pressure, wherein the second discharge pressure is greater than the
first discharge pressure, and when operating in the third operation
zone, the suction pressure of the compressor is greater than the
second suction pressure and the discharge pressure of the
compressor is greater than the second discharge pressure.
3. The simultaneous cooling-heating multiple type air conditioner
according to claim 2, wherein the air conditioner operating in the
first operation zone is configured to be controlled to move to the
second operation zone.
4. The simultaneous cooling-heating multiple type air conditioner
according to claim 2, wherein the air conditioner operating in the
third operation zone is configured to be controlled to move to the
second operation zone.
5. The simultaneous cooling-heating multiple type air conditioner
according to claim 2, wherein discharge flow of refrigerant from
the compressor is controlled in such a manner that the air
conditioner operating in the first operation zone is controlled to
move to the second operation zone.
6. The simultaneous cooling-heating multiple type air conditioner
according to claim 2, wherein discharge flow of refrigerant from
the compressor is controlled in such a manner that the air
conditioner operating in the third operation zone is controlled to
move to the second operation zone.
7. The simultaneous cooling-heating multiple type air conditioner
according to claim 2, further comprising an outdoor heat exchanger
for exchanging heat of the refrigerant with outdoor air and an
outdoor fan for blowing the outdoor air to the outdoor heat
exchanger, wherein the number of revolutions of the outdoor fan is
controlled in such a manner that the air conditioner is configured
to be controlled to move to the second operation zone if the air
conditioner is operating in the first operation zone, and the air
conditioner is configured to be controlled to move to the second
operation zone if the air conditioner is operating in the third
operation zone.
8. A simultaneous cooling-heating multiple type air conditioner,
comprising: a plurality of cooling-heating combined-use indoor
units, each indoor unit including a indoor heat exchanger; a
cooling-heating combined-use outdoor unit including a compressor,
an outdoor heat exchanger, and a switching part installed at a
discharge side of the compressor, for switching flow of refrigerant
based on operation conditions such as cooling-only operation,
heating-only operation, cooling-initiative simultaneous cooling and
heating operation, and heating-initiative simultaneous cooling and
heating operation; and a distributor installed between the
cooling-heating combined-use outdoor unit and the cooling-heating
combined-use indoor units, the distributor being configured to
distribute the refrigerant to the cooling-heating combined-use
indoor units based on the operation conditions such as cooling-only
operation, heating-only operation, cooling-initiative simultaneous
cooling and heating operation, and heating-initiative simultaneous
cooling and heating operation, wherein upon the simultaneous
cooling and heating operation of the cooling-heating combined-use
indoor units, the air conditioner is controlled in an operation
domain divided into a plurality of operation zones according to
refrigerant suction pressure and refrigerant discharge pressure of
the compressor, and wherein the operation domain includes a first
operation zone in which the cooling-initiative simultaneous cooling
and heating operation is switched to the heating-initiative
simultaneous cooling and heating operation, a second operation zone
in which the cooling-initiative simultaneous cooling and heating
operation or the heating-initiative simultaneous cooling and
heating operation is not switched to a different operation, and a
third operation zone in which the heating-initiative simultaneous
cooling and heating operation is switched to the cooling-initiative
simultaneous cooling and heating operation.
9. The simultaneous cooling-heating multiple type air conditioner
according to claim 8, wherein when operating in the first operation
zone, the suction pressure of the compressor is less than a first
suction pressure and the discharge pressure of the compressor is
less than a first discharge pressure, when operating in the second
operation zone, the suction pressure of the compressor is in a
range from the first suction pressure to a second suction pressure,
wherein the second suction pressure is greater than a first suction
pressure, and the discharge pressure of the compressor is in a
range from the first discharge pressure to a second discharge
pressure, wherein the second discharge pressure is greater than the
first discharge pressure, and when operating in the third operation
zone, the suction pressure of the compressor is greater than the
second suction pressure and the discharge pressure of the
compressor is greater than the second discharge pressure.
10. The simultaneous cooling-heating multiple type air conditioner
according to claim 9, wherein the air conditioner is controlled in
a manner such that the air conditioner operating in the first
operation zone is controlled to move to the second operation
zone.
11. The simultaneous cooling-heating multiple type air conditioner
according to claim 9, wherein the air conditioner is controlled in
a manner such that the air conditioner operating in the third
operation zone is controlled to move to the second operation
zone.
12. The simultaneous cooling-heating multiple type air conditioner
according to claim 8, wherein discharge flow of refrigerant from
the compressor is controlled in such a manner that the air
conditioner operating in the first operation zone is controlled to
move to the second operation zone.
13. The simultaneous cooling-heating multiple type air conditioner
according to claim 8, wherein discharge flow of refrigerant from
the compressor is controlled in such a manner that the air
conditioner operating in the third operation zone is controlled to
move to the second operation zone.
14. The simultaneous cooling-heating multiple type air conditioner
according to claim 8, further comprising an outdoor fan for blowing
the outdoor air to the outdoor heat exchanger, wherein the number
of revolutions of the outdoor fan is controlled in such a manner
that the air conditioner operating in the first operation zone is
controlled to move to the second operation zone.
15. The simultaneous cooling-heating multiple type air conditioner
according to claim 8, further comprising an outdoor fan for blowing
the outdoor air to the outdoor heat exchanger, wherein the number
of revolutions of the outdoor fan is controlled in such a manner
that the air conditioner operating in the third operation zone is
controlled to move to the second operation zone.
16. The simultaneous cooling-heating multiple type air conditioner
according to claim 8, wherein the distributor includes a liquid
header, a low pressure gas header and a high pressure gas
header.
17. The simultaneous cooling-heating multiple type air conditioner
according to claim 8, further comprising: a liquid refrigerant pipe
connected between the cooling-heating combined-use outdoor unit and
the liquid header; a low pressure gas pipe connected between the
cooling-heating combined-use outdoor unit and the low pressure gas
header; and a high pressure gas pipe connected between the
cooling-heating combined-use outdoor unit and the high pressure gas
header.
Description
[0001] This application claims the benefit of Korean Patent
Application No. 10-2006-0101754, filed on Oct. 19, 2006, which is
hereby incorporated by reference as if fully set forth herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a multiple type air
conditioner, and more particularly to a simultaneous
cooling-heating multiple type air conditioner configured to
simultaneously cool and heat.
[0004] 2. Discussion of Related Art
[0005] Generally, an air conditioner is an appliance for cooling
and heating an indoor space, such as a residential interior space,
a restaurant and an office. In order to effectively cool and heat
an indoor space divided into a plurality of rooms, multiple type
air conditioners, which can cool and heat respective rooms
independently have been developed. In particular, a multiple type
air conditioner is configured in such a manner that a plurality of
indoor units are connected to a single outdoor unit, and the indoor
units are installed in respective rooms. Each indoor unit operates
in either a cooling mode or a heating mode, and conditions air of
an indoor space.
[0006] However, the conventional multiple type air conditioners are
controlled to either cool or heat all the rooms in one indoor space
at the same time, and as such they can not meet the demand of
independently conditioning the respective rooms differently.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to provide a
simultaneous cooling-heating multiple type air conditioner that is
configured to be controlled steadily in a simultaneous cooling and
heating operation period.
[0008] In order to achieve the above objects and advantageous
effects, according to one aspect of the present invention, there is
provided a simultaneous cooling-heating multiple type air
conditioner controlled with an operation domain including a
plurality of operation zones which are divided based on a
refrigerant suction pressure and a refrigerant discharge pressure
of a compressor, in which the operation domain includes a first
operation zone in which a cooling-initiative simultaneous cooling
and heating operation mode is switched to a heating-initiative
simultaneous cooling and heating operation mode, a second operation
zone in which a mode switching between the cooling-initiative
simultaneous cooling and heating operation mode and the
heating-initiative simultaneous cooling and heating operation mode
does not occur, and a third operation zone in which the
heating-initiative simultaneous cooling and heating operation mode
is switched to the cooling-initiative simultaneous cooling and
heating operation mode.
[0009] According to a further aspect of the present invention,
there is provided a simultaneous cooling-heating multiple type air
conditioner including a plurality of cooling-heating combined-use
indoor units, each having an indoor heat exchanger, a
cooling-heating combined-use outdoor unit including a compressor,
an outdoor heat exchanger, and a refrigerant switching part
installed at a discharge side of the compressor for switching flow
of refrigerant based on operation conditions such as cooling-only
operation, heating-only operation, cooling-initiative simultaneous
cooling and heating operation, and heating-initiative simultaneous
cooling and heating operation, and a distributor installed between
the cooling-heating combined-use indoor units and the
cooling-heating combined-use outdoor unit for distributing the
refrigerant into passages of the cooling-heating combined-use
indoor units based on the operation conditions such as cooling-only
operation, heating-only operation, cooling-initiative simultaneous
cooling and heating operation, and heating-initiative simultaneous
cooling and heating operation, wherein the air conditioner is
controlled with an operation domain including a plurality of
operation zones which are divided according to a refrigerant
suction pressure and a refrigerant discharge pressure of the
compressor, in which the operation zone domain comprises a first
operation zone in which a cooling-initiative simultaneous cooling
and heating operation mode is switched to a heating-initiative
simultaneous cooling and heating operation mode, a second operation
zone in which a mode switching between the cooling-initiative
simultaneous cooling and heating operation mode and the
heating-initiative simultaneous cooling and heating operation does
not occur, and a third operation zone in which the
heating-initiative simultaneous cooling and heating operation mode
is switched to the cooling-initiative simultaneous cooling and
heating operation mode.
[0010] The suction pressure of the compressor is less than a first
suction pressure, a discharge pressure of the compressor is less
than a first discharge pressure in the first operation zone; the
suction pressure of the compressor ranges from the first suction
pressure to a second suction pressure wherein the second suction
pressure is greater than the first suction pressure and the
discharge pressure of the compressor ranges from the first
discharge pressure to a second discharge pressure wherein the
second discharge pressure is greater than the first discharge
pressure in the second operation zone; and the suction pressure of
the compressor may be greater than the second suction pressure and
the discharge pressure of the compressor may be greater than the
second discharge pressure. In this instance, the air conditioner
operating in the first operation zone and the third operation zone
can be controlled to move to the second operation zone by varying
discharge flow rate of refrigerant discharged from the compressor
or the number of revolutions of the outdoor fan.
[0011] The distributor may include a liquid header, a low pressure
gas header, and a high pressure gas header. The simultaneous
cooling-heating multi-air conditioner according to the present
invention may further include a liquid refrigerant pipe for
connecting the cooling-heating outdoor unit to the liquid header, a
low pressure gas pipe for connecting the cooling-heating outdoor
unit to the low pressure gas header, and a high pressure gas pipe
for connecting the cooling-heating outdoor unit to the high
pressure gas header.
[0012] Since the simultaneous cooling-heating multiple type air
conditioner according to the present invention switches its
operation modes in an operation domain divided into a plurality of
operation zones based on the refrigerant suction pressure and the
refrigerant discharge pressure of the compressor, it can be
steadily operated and controlled during the simultaneous cooling
and heating operation period.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic view illustrating a simultaneous
cooling-heating multiple type air conditioner according to one
embodiment of the present invention;
[0014] FIG. 2 is a view illustrating the operation status of the
simultaneous cooling-heating multiple type air conditioner shown in
FIG. 1, which operates in a cooling-only operation mode;
[0015] FIG. 3 is a view illustrating the operation status of the
simultaneous cooling-heating multiple type air conditioner shown in
FIG. 1, which operates in a heating-only operation mode;
[0016] FIG. 4 is a view illustrating the operation status of the
simultaneous cooling-heating multiple type air conditioner shown in
FIG. 1, which operates in a cooling-initiative simultaneous
cooling-heating operation mode;
[0017] FIG. 5 is a view illustrating the operation status of the
simultaneous cooling-heating multiple type air conditioner shown in
FIG. 1, which operates in a heating-initiative simultaneous
cooling-heating operation mode; and
[0018] FIG. 6 is a view illustrating an operation domain of the
simultaneous cooling-heating multiple type air conditioner shown in
FIG. 1, which is controlled to perform a simultaneous
cooling-heating operation.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0019] Hereinafter, a simultaneous cooling-heating multiple type
air conditioner according to embodiments of the present invention
will be described with reference to the accompanying drawings.
[0020] A multiple type air conditioner in which some indoor units
operate to cool air and the other indoor units operate to heat air
at the same time has been researched and developed. The
conventional multiple type air conditioner for simultaneous
cooling-heating operation is controlled based on a target discharge
pressure and a target suction pressure set for simultaneous
cooling-heating operation of a compressor. In this instance,
depending on cooling to heating operation ratio of the indoor units
operating in cooling mode or in heating mode, the simultaneous
cooling-heating multiple type air conditioner performs a
cooling-initiative simultaneous cooling and heating operation or a
heating-initiative simultaneous cooling and heating operation.
Accordingly, since the multiple type air conditioner for
simultaneous cooling and heating operations is controlled case by
case based on the operation ratio of the indoor units, indoor
temperature and outdoor temperature, there is a no-controlled zone
in which operation of the air conditioner can not be controlled by
the target discharge pressure and the target suction pressure.
[0021] Further, the conventional multiple type air conditioner
performing simultaneous cooling and heating operations is
disadvantageous in that it cannot respond to a variety of design
specifications, a variety range of indoor temperatures and a
variety range of outdoor temperatures. Accordingly, since the
conventional multiple type air conditioner performing simultaneous
cooling and heating operations does not have optimum operation
efficiency, it cannot sufficiently cool and heat an indoor space.
Still further, since the control scheme of the conventional
multiple type air conditioner performing simultaneous cooling and
heating operations is very complicated, an operation mode switching
time between the cooling-initiative simultaneous cooling and
heating operation and the heating-initiative simultaneous cooling
and heating operation is increased by 5 through 15 minutes, and
noise occurs during the operation mode switching time. Further,
damage is caused to a compressor when trying to reduce the mode
switching noise.
[0022] FIG. 1 illustrates a simultaneous cooling-heating multiple
type air conditioner 100 according to one embodiment of the present
invention. In this example, the simultaneous cooling-heating
multiple type air conditioner 100 includes a first, a second, a
third and a fourth cooling-heating combined-use indoor units B1,
B2, B3 and B4, a cooling-heating combined-use outdoor unit A, and a
distributor C.
[0023] The cooling-heating combined-use outdoor unit A includes a
first and a second compressor 53 and 54, an outdoor heat exchanger
51, an outdoor heat exchanger fan 61 and a switching part. The
switching part includes a four-way valve 62. Suction parts of the
first and second compressors 53 and 54 are connected to each other
through a combined-use accumulator 52. The first compressor 53 is
an inverter compressor that is configured to vary compression
capacity of refrigerant, and the second compressor 54 is a
constant-speed compressor having constant compression capacity of
refrigerant.
[0024] A first discharge pipe 55 and a second discharge pipe 56 are
connected to respective discharge sides of the first and second
compressors 53 and 54, and bridged by a bridging part 57. The first
and second discharge pipes 55 and 56 are further respectively
connected to a first and a second oil separator 58 and 59 in order
to recover oil from refrigerant discharged from the first and
second compressors 53 and 54. The first and second oil separators
58 and 59 are respectively connected to a first and a second
recovery pipe 30 and 31 in order to guide the separated oil to
respective suction sides of the first and second compressors 53 and
54.
[0025] The bridging part 57 is connected to a high pressure gas
pipe 63 in order to make refrigerant discharged from the first and
second compressors 53 and 54 bypass the four-way valve 62. The
bridging part 57 is connected to the four-way valve 62 via a third
discharge pipe 68.
[0026] An outdoor heat exchanger 51 is connected to the four-way
valve 62 via a first connection pipe 71. In the outdoor heat
exchanger 51, refrigerant condenses or evaporates by exchanging
heat with outdoor air. In order to facilitate heat exchanging, an
outdoor fan 61 blows air into the outdoor heat exchanger 51. The
outdoor heat exchanger 51 is configured to operate as a condenser
during a cooling-only operation period or a cooling-initiative
simultaneous cooling-heating operation period, and is configured to
operate as an evaporator during a heating-only operation period or
a heating-initiative simultaneous cooling-heating operation
period.
[0027] An outdoor electronic expansion valve 65 and an overcooling
device 66 are installed between or in the middle of the liquid pipe
72, connected between the outdoor heat exchanger 51 and the
distributor C. The outdoor electronic expansion valve 65 expands
refrigerant upon the heating-only operation and the
heating-initiative simultaneous cooling-heating operation. The
overcooling device 66 cools the refrigerant moving to the
distributor upon the cooling-only operation and the
cooling-initiative simultaneous cooling-heating operation. The
outdoor electronic expansion valve 65 expands the refrigerant
condensed in the first through fourth indoor heat exchangers 11,
21, 31 and 41 during the heating-only operation period or the
heating-initiative simultaneous cooling-heating operation period
before the refrigerant is introduced into the outdoor heat
exchanger 51. The overcooling device 66 includes an overcooler 66a
installed in such a manner that it surrounds a part of the liquid
pipe 72, a bypass pipe 66b installed between the overcooler 66a and
the distributor C in order to make a portion of the refrigerant
moving to the distributor bypass the distributor so as to be
introduced into the overcooler 66a, an electronic expansion valve
66c installed in a part of the bypass pipe 66b, and a recovery pipe
66d connected between the overcooler 66a and a third discharge pipe
64.
[0028] The distributor C is installed between the cooling-heating
combined-use outdoor unit A and the first through fourth
cooling-heating combined-use indoor units B1, B2, B3 and B4 and
distributes the refrigerant to the first, second, third and fourth
cooling-heating combined-use indoor units B1, B2, B3 and B4 based
on the operation conditions such as cooling-only operation,
heating-only operation, cooling-initiative simultaneous
cooling-heating operation and heating-initiative simultaneous
cooling-heating operation. The distributor C includes a high
pressure gas header 81, a low pressure gas header 82, a liquid
header 83 and control valves (not shown).
[0029] The first, second, third and fourth cooling-heating
combined-use indoor units B1, B2, B3 and B4 includes respective
first, second, third and fourth electronic expansion valves 12, 22,
32 and 42, and respective first, second, third and fourth indoor
fans 15, 25, 35 and 45. The first, second, third and fourth
electronic expansion valves 12, 22, 32 and 43 are installed on
respective first, second, third and fourth connection pipes 13, 23,
33 and 43 connected between the first, second, third and fourth
indoor heat exchangers 11, 21, 31 and 41 and the high pressure gas
header 81.
[0030] The high pressure gas header 81 is connected to the high
pressure gas pipe 63 of the bridging part 57, and respective sides
of the first, second, third and fourth indoor heat exchangers 11,
21, 31 and 41. The low pressure gas header 82 is connected to the
lower pressure gas pipe 75, which the low pressure gas header 82 is
connected to the suction pipe 64, and connected to respective other
sides of the first, second, third and fourth heat exchangers 11,
21, 31, and 41. The high pressure gas header 81, the low pressure
gas header 82 and the liquid header 83 can be respectively
connected to a high pressure gas pipe 63', a low pressure gas pipe
75' and a liquid pipe 72' of a different outdoor unit (not
shown).
[0031] Referring to FIG. 2 through FIG. 5, the operation statuses
of the simultaneous cooling-heating multiple type air conditioner
shown in FIG. 1 and flow of refrigerant according to the operation
methods will be described below.
[0032] FIG. 2 illustrates the operation status of the simultaneous
cooling-heating multiple type air conditioner and the flow of
refrigerant upon a cooling-only operation. The refrigerant at a
high pressure gas state discharged from the first and second
compressors 53 and 54 pass through the first and second discharge
pipes 55 and 56, and finally flow into the outdoor heat exchanger
51 through the third discharge valve 68 and the four-way valve 62.
High pressure liquid refrigerant, obtained as the high pressure gas
refrigerant is condensed by the outdoor heat exchanger 51, is
introduced into the liquid header 83 via the overcooling device 66.
The refrigerant discharged from the liquid header 83 through the
first, second, third and fourth indoor connection pipes 13, 23, 33
and 43 is expanded by the first, second, third and fourth
electronic expansion valves 12, 22, 32 and 42, then evaporated by
the first, second, third and fourth indoor heat exchangers 11, 21,
31 and 41, and finally introduced into the low pressure gas header
82. Low pressure gas refrigerant discharged from the low pressure
gas header 82 is introduced into the suction and discharge pipe 64
and then sucked into the first and second compressors 53 and 54 via
the accumulator 52.
[0033] FIG. 3 illustrates the operation status of the simultaneous
cooling-heating multiple type air conditioner 100 and the flow of
refrigerant in the air conditioner 100 upon the heating-only
operation. The high pressure gas refrigerant discharged from the
first and second compressors 53 and 54 pass through the first and
second discharge pipes 55 and 56, then pass through the bridging
part 57 and the high pressure gas pipe 63 and is finally introduced
into the high pressure gas header 81 without passing by way of the
four-way valve 62. The refrigerant discharged from the high
pressure gas header 81 via fifth, sixth, seventh and eighth indoor
connection pipes 14, 24, 34 and 44 is condensed in the first,
second, third and fourth indoor heat exchangers 11, 21, 31 and 41.
After that, the refrigerant is introduced into the liquid header
83, next discharged through the liquid pipe 72, then expanded by
the outdoor electronic expansion valve 65, and finally evaporated
in the outdoor heat exchanger 51. The low pressure gas refrigerant
flows to the suction pipe 64 via the four-way valve 62, and then is
introduced into the first and second compressors 53 and 54 via the
accumulator 52.
[0034] FIG. 4 illustrates the operation status of the simultaneous
cooling-heating multiple type air conditioner 100 and the flow of
refrigerant in the air conditioner 100 upon the cooling-initiative
simultaneous cooling and heating operation. For example, FIG. 4
illustrates a case in which the first, second, and third indoor
units B1, B2 and B3 operate in a cooling mode and the fourth indoor
unit B4 operates in a heating mode. The flow of refrigerant in the
first, second and third indoor units B1, B2 and B3 operating in the
cooling mode are similar to or the same as that shown in the
cooling-only operation mode shown in FIG. 2. The operation shown in
FIG. 4 will thereby be described below, mainly by referencing some
of the differences of FIG. 4 with respect to FIG. 2.
[0035] A portion of the high pressure gas refrigerant discharged
from the first and second compressors 53 and 54 passes through the
high pressure gas pipe 63 via the bridging part 57, and is then
introduced into the high pressure gas header 81. The refrigerant
flowing out of the high pressure gas header 81 passes through the
indoor connection pipe 44, is then condensed in the fourth indoor
heat exchanger 41, and is finally introduced into the liquid header
83. The refrigerant flowing out of the fourth indoor unit B4 and
the refrigerant flowing out of the outdoor heat exchanger 51, are
introduced into respective first, second and third indoor units B1,
B2 and B3, via the liquid header 83.
[0036] FIG. 5 illustrates the operation status of the simultaneous
cooling-heating multiple type air conditioner 100 and the flow of
refrigerant in the air conditioner 100 upon the heating-initiative
simultaneous cooling and heating operation. For example, FIG. 5
illustrates a case in which the first, second, and third indoor
units B1, B2 and B3 operate in a heating mode and the fourth indoor
unit B4 operates in a cooling mode. The flow of refrigerant in the
first, second and third indoor units B1, B2 and B3 operating in the
heating mode are similar to or the same as that shown in the
heating-only operation shown in FIG. 3. The refrigerant in the
fourth indoor unit B4 flows differently. High pressure liquid
refrigerant is introduced into the fourth indoor unit B4, after
passing through the fourth connection pipe 43 from the liquid
header 83. Prior to arriving at the liquid header 83, the flow of
refrigerant is similar to the flow of refrigerant in FIG. 2. The
refrigerant is then expanded in the fourth indoor electronic
expansion valve 42, and evaporated in the fourth indoor heat
exchanger 41, and introduced into the low pressure gas header 82.
After that, the refrigerant passes through the low pressure gas
pipe 75, and flows into the third discharge pipe 64 so that it is
mixed with the refrigerant evaporated by the outdoor heat exchanger
51.
[0037] FIG. 6 illustrates the operation domain 150 of the
simultaneous cooling-heating operation of the first, second, third
and fourth cooling-heating combined-use indoor units B1, B2, B3 and
B4. The operation domain 150 is characterized by or divided into a
plurality of operation zones. The multi-type air conditioner
operates in a particular zone depending on refrigerant suction
pressures and refrigerant discharge pressures of the first and
second compressors 53 and 54. The refrigerant discharge pressure
may be set by a value measured by pressure sensors installed to the
discharge pipes of the first and second compressors 53 and 54, or
set by a value measured by a pressure sensor installed to the third
discharge pipe.
[0038] The operation domain may be characterized and divided in a
matrix form and includes a first operation zone R1, a second
operation zone R2 and a third operation zone R3. In the first
operation zone R1, the suction pressure of the first and second
compressors 53 and 54 is less than a first suction pressure P1, and
the discharge pressure of the first and second compressors 53 and
54 is less than a first discharge pressure P3. In the second
operation zone R2, the suction pressure of the first and second
compressors 53 and 54 is equal to or greater than the first suction
pressure P1 and less than a second suction pressure P2. The second
suction pressure P2 is greater than the first suction pressure P1
(P2>P1). In the second operation zone R2, the discharge pressure
of the first and second compressors 53 and 54 is equal to or
greater than the first discharge pressure P3 and is equal to or
less than a second discharge pressure P4. The second discharge
pressure P4 is greater than the first discharge pressure P3
(P4>P3). In the third operation zone R3, the suction pressure of
the first and second compressors 53 and 54 is greater than the
second suction pressure P2 and the discharge pressure of the first
and second compressors 53 and 54 is greater than the second
discharge pressure P4. To further illustrate this example, the
first suction pressure P1 may be 725 kPa (gauge pressure), the
second suction pressure P2 may be 987 kPa (gauge pressure), the
first discharge pressure P3 may be 2565 kPa (gauge pressure) and
the second discharge pressure P4 may be 2985 kPa (gauge
pressure).
[0039] The simultaneous cooling-heating multiple type air
conditioner 100 performs switching of the cooling-initiative
simultaneous cooling and heating operation mode when operating in
the first operation zone R1. That is, the simultaneous
cooling-heating multiple type air conditioner 100 performing the
cooling-initiative simultaneous cooling and heating operation
switches its operation mode so as to perform the heating-initiative
simultaneous cooling and heating operation when the suction
pressure or the discharge pressure of the first and second
compressors 53 and 54 decreases and it comes into the range of the
first operation zone R1.
[0040] In the third operation zone R3, the simultaneous
cooling-heating multiple type air conditioner 100 switches its
operation mode from the heating-initiative simultaneous cooling and
heating operation to the cooling-initiative simultaneous cooling
and heating operation. That is, the simultaneous cooling-heating
multiple type air conditioner 100 performing the heating-initiative
simultaneous cooling and heating operation switches to the
cooling-initiative simultaneous cooling and heating operation when
at least one of the suction pressure and the discharge pressure of
the first and second compressors 53 and 54 increases and it comes
into the third operation zone R3.
[0041] The second operation zone R2 is a normal operation zone in
which operation mode switching does not occur in this operation
zone. As an example, the simultaneous cooling-heating multiple type
air conditioner 100 performing the heating-initiative simultaneous
cooling and heating operation in the first operation zone R1, keeps
or maintains the heating-initiative simultaneous cooling and
heating operation even if the suction pressure or the discharge
pressure of the first and second compressors 53 and 54 increases
provided it comes into the second operation region R2. As an
alternative example, the simultaneous cooling-heating multiple type
air conditioner 100 performing the cooling-initiative simultaneous
cooling and heating operation in the third operation zone R3, keeps
or maintains the cooling-initiative simultaneous cooling and
heating operation even if the suction pressure or the discharge
pressure of the first and second compressors 53 and 54 decreases
provided it comes into the second operation zone R2.
[0042] The simultaneous cooling-heating multiple type air
conditioner 100 operating in the first operation zone R1 and the
third operation zone R3 is controlled to move to the second
operation zone R2. There can be a variety of control methods. For
example, the refrigerant discharge flow of the first and second
compressors 53 and 54 can be controlled. The frequency of the first
compressor 53 may be varied or the refrigerant discharge flow can
be varied by on/off control of the second compressor 54. Further,
the number of rotations of the outdoor fan 61 can be varied. For
example, when the simultaneous cooling-heating multiple type air
conditioner 100 performs the cooling-initiative simultaneous
cooling and heating operation in the third operation zone R3, if
the refrigerant discharge flow of the first and second compressors
53 and 54 is increased or the number of rotation of the outdoor fan
61 is increased, operation of the simultaneous cooling-heating
multiple type air conditioner 100 moves to the second operation
zone R2. The time it takes for the first operation zone R1 or the
third operation zone R3 to move to second operation zone R2 can be
greatly reduced, for example, to approximately 3 minutes or less.
In contrast, conventional operation zone switching time is about 5
to 15 minutes. Accordingly, since the time when the simultaneous
cooling-heating multiple type air conditioner 100 steadily operates
in the second operation zone R2 is increased, optimum air
conditioning cycle efficiency can be realized and the control
scheme can be simplified.
[0043] Various embodiments of the present invention are explained
above, but the present invention is not limited to the above-stated
embodiments. Those skilled in the art will appreciate that many
variations and modifications can be made to the preferred
embodiments without substantially departing from the principles of
the present invention. Therefore, it is readily understood that
those variations and modifications to the preferred embodiment will
be within the scope of the claims.
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