U.S. patent application number 12/958915 was filed with the patent office on 2011-10-06 for air conditioner and method of controlling the same.
Invention is credited to Seheon Choi, Byeongchul Lee, Inho Won.
Application Number | 20110239667 12/958915 |
Document ID | / |
Family ID | 44310311 |
Filed Date | 2011-10-06 |
United States Patent
Application |
20110239667 |
Kind Code |
A1 |
Won; Inho ; et al. |
October 6, 2011 |
AIR CONDITIONER AND METHOD OF CONTROLLING THE SAME
Abstract
An air conditioner and a method of operating the same are
provided. The air conditioner may include a plurality of
compressors, each of which may include a casing that stores oil
therein, and an oil level detecting device that detects an oil
level within the casing. Once oil levels within each of the
plurality of compressors are detected, oil may be redistributed
between the plurality of compressors without interrupting a normal
operation of the air conditioner. Oil may be transferred from a
compressor having an oil level greater than a desired amount to a
compressor having an oil level less than the desired amount. If
there remains a compressor that contains an insufficient amount of
oil after redistributing the oil among the plurality of
compressors, an oil collecting operation may be performed.
Inventors: |
Won; Inho; (Seoul, KR)
; Choi; Seheon; (Seoul, KR) ; Lee; Byeongchul;
(Seoul, KR) |
Family ID: |
44310311 |
Appl. No.: |
12/958915 |
Filed: |
December 2, 2010 |
Current U.S.
Class: |
62/84 |
Current CPC
Class: |
F25B 2500/16 20130101;
F25B 31/004 20130101; F25B 2400/075 20130101; F25B 2700/03
20130101 |
Class at
Publication: |
62/84 |
International
Class: |
F25B 43/00 20060101
F25B043/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 1, 2010 |
KR |
10-2010-0030120 |
Claims
1. An operating method for an air conditioner, the air conditioner
comprising a plurality of compressors, each of which includes a
casing that stores oil in an inner lower portion thereof and an oil
level detecting device that detects an oil level in the casing; at
least one first heat exchanger that intakes a working fluid from
the plurality of compressors; at least one expansion device; at
least one second heat exchanger, through which the working fluid
passes after passing through the at least one first heat exchanger;
a first suction pipe, through which the working fluid flows from
the at least one first heat exchanger or the at least one second
heat exchanger; and a plurality of second suction pipes branched
from the first suction pipe and then connected to each of the
compressors, the method comprising: detecting an oil level of each
of the plurality of compressors; distributing oil in a first
compressor of the plurality of compressors containing oil over a
first preset level for the first compressor toward a second
compressor of the plurality of compressors containing oil lower
than a second preset level for the second compressor via the first
and the second suction pipes without passing through the at least
one first exchanger and the at least one second heat exchanger when
a number of the plurality of compressors containing oil lower than
the preset level for the respective compressor is less than or
equal to a predetermined number; and performing an oil collecting
operation if there exists a compressor containing oil lower than a
preset level for that compressor after performing the distributing
or if the number of the plurality of compressors containing oil
lower than the preset level for the respective compressor is
greater than the predetermined number.
2. The method of claim 1, wherein the preset level of each of the
plurality of compressors are all the same or all different.
3. The method of claim 1, wherein the preset level of at least two
of the plurality of compressors are the same or different.
4. The method of claim 1, wherein the distributing is performed for
a predetermined period of time, at predetermined time intervals, or
until all of the plurality of compressors have at least the preset
level for the respective compressor.
5. The method of claim 1, wherein each of the plurality of
compressors includes a first oil return pipe that connects the
casing of the respective compressor to the first suction pipe, and
wherein oil in the respective compressor containing oil over the
preset level for the respective compressor is supplied to the first
suction pipe via the first oil return pipe during the
distributing.
6. The method of claim 5, wherein the first oil return pipe
connected to a compressor containing oil lower than a preset level
for each compressor remains closed during the distributing.
7. The method of claim 1, wherein the air conditioner further
comprises at least one oil separator having a second oil return
pipe that connects the oil separator and the first suction pipe,
and wherein oil collected in the oil separator is supplied to the
first suction pipe via the second oil return pipe during the
distributing.
8. The method of claim 7, wherein the at least one oil separator
receives a mixture of oil and working fluid from at least one of
the plurality of compressors through an oil discharge pipe.
9. The method of claim 7, wherein the at least one oil separator
stores the oil from the plurality of compressors and if the number
of the plurality of compressors containing oil lower than the
preset level for the respective compressor is greater than the
predetermined number, the method further comprises: detecting an
oil level of the at least one oil separator; if the oil level of
the at least one oil separator is less than a preset level for the
at least one oil separator, performing the oil collecting
operation; and if the oil level of the at least one oil separator
is greater than or equal to the preset level, opening a valve that
allows the stored oil to flow into the compressor containing oil
lower than the preset level for the respective compressor.
10. The method of claim 1, wherein the air conditioner further
comprises a plurality of oil separators, and wherein each of the
plurality of compressors discharges a mixture of oil and working
fluid to a respective one of the plurality of oil separators.
11. The method of claim 10, wherein the distributing includes
distributing the oil stored in the at least one oil separator
toward the second compressor of the plurality of compressors
containing oil lower than the second preset level for the second
compressor.
12. The method of claim 1, wherein the air conditioner further
comprises a first oil return pipe that connects the casing of each
compressor to the first suction pipe, and wherein oil in the
respective compressor containing oil over a preset level for each
compressor and the oil in the oil separator are supplied to the
first suction pipe via the first and second oil return pipes during
the distributing.
13. The method of claim 1, wherein the air conditioner further
comprises at least one oil reservoir that stores the oil from the
plurality of compressors and if the number of the plurality of
compressors containing oil lower than the preset level for the
respective compressor is greater than the predetermined number, the
method further comprises: detecting an oil level of the at least
one oil reservoir; if the oil level of the at least one reservoir
is less than a preset level for the at least one oil reservoir,
performing the oil collecting operation; and if the oil level of
the at least one reservoir is greater than or equal to the preset
level of the at least one oil reservoir, opening a reservoir valve
of the at least one reservoir as part of the distributing.
14. The method of claim 13, wherein each of the plurality of
compressors includes a first oil return pipe that connects the
casing of the respective compressor to the at least one oil
reservoir, and wherein oil in the respective compressor containing
oil over the preset level for the respective compressor is supplied
to the at least one oil reservoir via the first oil return
pipe.
15. The method of claim 14, wherein the first oil return pipe
connected to the compressor containing oil lower than a preset
level for each compressor remains closed during the
distributing.
16. The method of claim 13, wherein the at least one oil reservoir
functions as an oil separator.
17. The method of claim 16, wherein the oil separator receives a
mixture of oil and working fluid from at least one of the plurality
of compressors through an oil discharge pipe.
18. An operating method for an air conditioner, the air conditioner
comprising a plurality of compressors, each having an oil level
detecting device, an oil transferring device that transfers oil
among the plurality of compressors, and a plurality of heat
exchangers and expansion devices that cooperate with the plurality
of compressors, the method comprising: detecting an oil level of
each of the plurality of compressors; transferring oil from at
least one compressor of the plurality of compressors with a
relatively higher oil level to at least one compressor of the
plurality of compressors with a relatively lower oil level when a
number of the plurality of compressors containing oil lower than
the preset level for the respective compressor is less than or
equal to a predetermined number; and performing an oil collecting
operation if a number of compressors containing oil lower than a
preset level for the respective compressor is greater than a
predetermined number.
19. The method of claim 18, wherein the method further comprises
performing the oil collecting operation when a compressor
containing oil lower than the preset level is detected after
transferring the oil for a predetermined period of time.
20. The method of claim 18, wherein the transferring comprises
transferring the oil without passing through the plurality of heat
exchangers and expansion devices that cooperate with the plurality
of compressors.
21. The method of claim 20, wherein the method further comprises
closing an oil return pipe connected to the compressor containing
oil lower than the preset level for the respective compressor
during the transferring.
22. An operating method for an air conditioner, the air conditioner
comprising a plurality of compressors, each having an oil level
detecting device, an oil transferring device that transfers oil
among the plurality of compressors, and a plurality of heat
exchangers and expansion devices that cooperate with the plurality
of compressors, the method comprising: detecting an oil level of
each of the plurality of compressors; transferring oil from at
least one compressor of the plurality of compressors with a
relatively higher oil level to at least one compressor of the
plurality of compressors with a relatively lower oil level when a
number of the plurality of compressors containing oil lower than
the preset level for the respective compressor is less than or
equal to a predetermined number; storing oil from at least one of
the plurality of compressors during a normal operation of the air
conditioner in at least one oil reservoir or at least one oil
separator; detecting an oil level of the at least one oil reservoir
or the at least one oil separator when the number of compressors
containing oil lower than the preset level for the respective
compressor is greater than the predetermined number; performing an
oil collecting operation when the oil level of the at least one oil
reservoir or the at least one oil separator is less than a preset
level for the at least one oil reservoir or the at least one oil
separator; and transferring the stored oil to the at least one
compressor of the plurality of compressors with the relatively
lower oil level when the oil level of the at least one oil
reservoir or the at least one oil separator is greater than or
equal to the preset level for the at least one oil reservoir or the
at least one oil separator.
23. The method of claim 22, wherein the at least one oil reservoir
or the at least one oil separator comprises at least one oil
separator, and wherein the at least one oil separator receives a
mixture of oil and working fluid from at least one of the plurality
of compressors through an oil discharge pipe.
24. The method of claim 23, wherein the method further comprises
separating the mixture of oil and working fluid at the at least one
oil separator, and storing the separated oil and transferring the
separated working fluid to the plurality of heat exchangers and
expansion devices that cooperate with the plurality of
compressors.
25. The method of claim 23, wherein each of the plurality of
compressors includes a valve that controls a flow of the stored oil
from the at least one oil separator to each respective compressor,
and wherein the method further comprises opening the valve of the
compressor containing oil lower than the preset level during the
transferring of the stored oil.
26. The method of claim 22, wherein the at least one oil reservoir
or the at least one oil separator comprises at least one oil
reservoir.
27. The method of claim 26, wherein the at least one oil reservoir
functions as an oil separator.
28. The method of claim 27, wherein each of the plurality of
compressors includes a valve that controls a flow of oil in the oil
return pipe from each respective compressor to the at least one oil
reservoir, and wherein the method further comprises closing the
valve of the compressor containing oil lower than the preset level
during the transferring.
29. The method of claim 26, wherein each of the plurality of
compressors communicates with a respective one of a plurality of
oil separators.
30. The method of claim 26, wherein the at least one oil reservoir
receives oil from at least one of the plurality of compressors
through a respective oil return pipe that connects the casing of
each compressor to the at least one oil reservoir.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims priority under 35 U.S.C. .sctn.119
to Korean Application No. 10-2010-0030120 filed in Korea on Apr. 1,
2010, whose entire disclosure(s) is/are hereby incorporated by
reference.
BACKGROUND
[0002] 1. Field
[0003] An air conditioner and a method of controlling the same are
disclosed herein.
[0004] 2. Background
[0005] Air conditioner and methods of controlling the same are
known. However, they suffer from various disadvantages.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Embodiments will be described in detail with reference to
the following drawings in which like reference numerals refer to
like elements, and wherein:
[0007] FIG. 1 is a schematic diagram of an air conditioner having a
plurality of compressors according to an embodiment;
[0008] FIG. 2 is a cross-sectional view of internal structure of a
compressor and an oil separator of FIG. 1;
[0009] FIG. 3 is a flow chart of a method of operating the air
conditioner of FIG. 1;
[0010] FIG. 4 is a schematic diagram of an air conditioner having a
plurality of compressors according to another embodiment;
[0011] FIG. 5 is a flow chart of a method of operating the air
conditioner of FIG. 4;
[0012] FIG. 6 is a schematic diagram of an air conditioner having a
plurality of compressors according to another embodiment; and
[0013] FIG. 7 is a flow chart of a method of operating the air
conditioner of FIG. 6.
DETAILED DESCRIPTION
[0014] A compressor, as broadly described and embodied herein, may
include a drive motor that provides a driving force to a
compression device to compress refrigerant while operating in
conjunction with the drive motor. The compressor may be categorized
as, for example, a reciprocating type, a scroll type, a rotary
type, or a vibration type, depending on the method by which the
refrigerant is compressed. Reciprocating type, scroll type, and
rotary type compressors use a rotary motion of the drive motor,
while vibration type compressors use a reciprocating motion of the
drive motor.
[0015] The drive motor of a rotary type compressor may be provided
with a crankshaft that transfers the rotary motion of the drive
motor to the compression device. For example, the drive motor of
the rotary compressor may include a stator fixed to a container or
case, a rotor positioned in the stator with a predetermined gap
therebetween to rotate in interaction with the stator, and a
crankshaft connected to the rotor to transfer rotary power to the
compression device. In addition, the compression device may be
combined with the crankshaft to suction, compress, and discharge
refrigerant while rotating inside a cylinder. A plurality of
bearing members may be provided to form a compression space between
the crank shaft and the compression device, and may also support
the compression device.
[0016] In the compressor having the foregoing structure, the
refrigerant may be compressed by rotating the compression device
with rotary motion generated by the drive device. The compressor
may be provided with an oil supply device to supply oil to the
compression device that facilitates the rotation of the compression
device as well as easily dissipates heat generated during operation
of the drive device. The oil supply device may be provided at a
lower end portion of the crankshaft. The oil may be stored in a
lower portion of the container or case, and may be pumped through
an oil flow path formed inside the crankshaft by the rotation of
the crankshaft. The pumped oil may then be supplied to each
component inside the compressor.
[0017] In compressors of various air conditioning systems, the oil
flow path, or pipe, in which the working fluid flows, may be
lengthened, requiring an increased amount of oil to operate the
compressor. Thus, it may be difficult to estimate when, where, and
how much oil will remain, and accordingly, it may be difficult to
maintain the oil level inside each compressor in an appropriate
condition or level. As a result, the oil level in the oil storage
space may become irregular and may vary outside of acceptable
levels during operation of the respective compressor, even when the
oil levels were within a suitable range at an initial stage of the
operation.
[0018] Therefore, it may be necessary to continuously check the oil
level inside each compressor during operation of the air
conditioner. If it is determined that the oil level is not in an
appropriate condition, then an oil collecting operation to add oil
to the compressor may be performed. However, it may be difficult to
manually check the oil level in each compressor, and therefore, the
oil collecting operation may be performed at predetermined
intervals regardless of the actual oil level. Performing the oil
collecting operation irrespective of the actual oil levels may be
inefficient as energy may be wasted during unnecessary oil
collecting operations.
[0019] To overcome this problem, an oil level sensor or detecting
device may be provided in the compressor to measure the oil level
to determine whether an oil collecting operation is necessary. One
such oil detecting device for a compressor is disclosed in
co-pending application Ser. No ______ (Attorney Docket No. P-1047),
which is hereby incorporated by reference. Thus, the number of
unnecessary oil collecting operations may be reduced, and may
result in decreased energy consumption as well as decreased
compressor downtime.
[0020] FIG. 1 is a schematic diagram of an air conditioner having a
plurality of compressors according to an embodiment. Referring to
FIG. 1, the air conditioner may include a plurality of compressors
100, 100', 100'', all of which may have the same structure. Each
compressor may include a first suction pipe 110, through which
refrigerant may flow, and a second suction pipe 112, 112', 112''
branched off from the first suction pipe 110 to each respective
compressor 100, 100', 100''. In addition, compressed refrigerant
may be discharged from each compressor 100, 100', 100'' through
respective discharge pipes 114, 114', 114''.
[0021] Oil may be stored inside the compressor, which may serve to
lower friction within the compressor during operation. Further, an
oil level detecting sensor 102, 102', 102'' that detects the level
of the oil may be provided at a lateral surface of each respective
compressor. A first oil return pipe 120, 120', 120'' may also be
provided at each compressor, that connects each respective
compressor 100, 100', 100'' to the first suction pipe 110 to
redistribute the oil received from the first oil return pipe 120,
120', 120''. The first oil return pipes 120, 120', 120'' may be
provided with capillary tubes 124, 124', 124'', respectively, that
reduce the pressure of oil. Moreover, the first oil return pipes
120, 120', 120'' may be provided with solenoid valves 126, 126',
126'', respectively, to open or close the first oil return pipes
120, 120', 120''.
[0022] The discharge pipes 114, 114', 114'', which each discharges
a mixture of oil and refrigerant from the respective compressor,
may be provided with oil separators 130, 130', 130'', respectively.
The oil separators 130, 130', 130'', which separate the discharged
oil from the refrigerant, may transfer the separated oil through
second oil separators 132, 132', 132'', respectively, to the first
suction pipe 110. The separated refrigerant, and any remaining oil,
may be discharged from the oil separators 130, 130', 130'' to a
4-way valve 140. Thus, the discharged oil may be separated from the
refrigerant by the oil separators 130, 130', 130'' and resupplied
to the compressors 100, 100', 100'' through the first suction pipe
110 and the second suction pipes 112, 112', 112''.
[0023] The 4-way valve 140 may include, for example, three
discharge ports, which may be connected to an accumulator 180, an
outdoor-side heat exchanger 150, and one or more indoor-side heat
exchanger(s) 170, 170', 170'', respectively. The air conditioner
may provide either cooling or heating based on a switching state of
the 4-way valve 140. Simply for ease of explanation, the 4-way
valve as shown in FIG. 1 is configured to provide cooling to the
indoor-side.
[0024] In the embodiment of FIG. 1, the refrigerant discharged from
the 4-way valve 140 may be passed through the outdoor-side heat
exchanger 150 and expansion apparatuses 160, 160', 160''. The
refrigerant may then be passed into the indoor-side heat exchangers
170, 170', 170'', which use the refrigerant to lower an indoor
temperature. The refrigerant may then pass through the 4-way valve
140 into the accumulator 180. Once refrigerant remaining in a
liquid state is separated from refrigerant in a gaseous state, the
accumulator 180 may pass the gaseous refrigerant to the first
suction pipe 110.
[0025] FIG. 2 is a cross-sectional view of internal structure of a
compressor and an oil separator of FIG. 1. Compressors 100', 100''
and oil separators 130', 130'' of FIG. 1 may have the same
structure as compressor 100 and oil separator 130 of FIG. 1.
Therefore, repetitive description of the compressors 100', 100''
and oil separators 130', 130'' has been omitted hereinafter.
[0026] Simply for ease of explanation, embodiments are described
herein in the form of a scroll compressor. However, embodiments are
not limited thereto and may be applied to or employ any type of
compressor in which oil is stored inside of the compressor.
Referring to FIG. 2, a main frame 20 and a sub frame 30 may be
provided inside a container or case 10, and a drive motor 40, which
is a driving device, may be provided between the main frame 20 and
sub frame 30. A compression device that compresses refrigerant may
be combined with the drive motor 40. The compression device may
include a fixed scroll 50 and an orbiting scroll 60, which may be
provided at an upper side of the main frame 20. Further, a suction
port SP may be formed on the container 10 and may be connected to
the second suction pipe 112. The compressed refrigerant may be
supplied from the compressor 100 to the oil separator 130 via the
discharge pipe 114.
[0027] The oil separator 130 may include a discharge pipe 131 at an
upper side thereof and discharge port 133 at a lower side thereof.
The discharge port 133 may be connected to the second oil return
pipe 132. The discharge pipe 131 may extend to a middle portion of
the oil separator 130, and thus, may lengthen a flow path of the
compressed refrigerant in the oil separator 130. Accordingly, as
compressed refrigerant is discharged from the discharge pipe 131 to
the 4-way valve 140, any oil that remains in the compressed
refrigerant may be separated therefrom and collected in a lower
portion of the oil separator 130. The separated oil, once
collected, may be discharged from the oil separator 130 via the
discharge port 133 to the second oil return pipe 132.
[0028] The drive motor 40 may include a stator 41, which may be
wound with a coil, a rotor 42 rotatably inserted in the stator 41,
and a rotating shaft 43 attached to a center of the rotor 42 that
transfers rotary force to a compression mechanism. A driving pin
portion 44 may be formed to protrude at an upper end of the
rotating shaft 43. The driving pin portion 44 may be formed
adjacent to a rotational axis of the rotating shaft 43. That is,
the driving pin portion 44 may be positioned away from a rotational
center of the rotating shaft 43.
[0029] The compressor 100 may further include the fixed scroll 50,
which may be fixed to an upper surface of the main frame 20, the
orbiting scroll 60, which may be placed on an upper surface of the
main frame 20 and engaged with the fixed scroll 50, and an Oldham
ring 70 disposed between the orbiting scroll 60 and the main frame
20 to prevent the rotation of the orbiting scroll 60. A fixed wrap
51 may be spirally wound and formed on the fixed scroll 50.
Further, an orbiting wrap 61 may be spirally wound and formed on
the orbiting scroll 60. The fixed wrap 51 together with the
orbiting wrap 61 may form a compression chamber (P). A boss portion
62 may protrude at a bottom surface of the orbiting scroll 60, for
example, a lateral surface opposite the orbiting wrap 61. The boss
portion 62 may engage the rotating shaft 43 to receive a rotary
force therefrom.
[0030] A sliding bush 63 may be combined with the driving pin
portion 44 of the rotating shaft 43 to slide in a radial direction.
The sliding bush 63 may then be combined with the boss portion 162
of the orbiting scroll 60 to slide in a rotating direction. An
external diameter of the sliding bush 63 may be formed to be the
same as an internal diameter of the boss portion 62 of the orbiting
scroll 60, to thereby reduce friction between the rotating shaft 43
and the orbiting scroll 60. Further, a main frame bush 22 may be
provided on an inside surface of the main frame 120 to reduce
friction between the rotating shaft 43 and main frame 20. Oil may
be supplied by an oil feeder 180 provided at a lower end portion of
the rotating shaft 43 to lubricate each of the bushes 22, 63.
[0031] The oil may be stored in an oil storage space formed by an
inner surface of a base 12 of the container 10. The oil may be
pumped from the oil storage space and supplied to the compression
device through an oil flow path 43a formed inside the rotating
shaft 43. The oil feeder 80, which may be provided at a lower end
portion of the oil flow path 43a, may rotate with the rotating
shaft 43 to pump the oil from the oil storage space into the oil
flow path 43a. The pumped oil may then be supplied to the
compression device positioned at an upper portion of the oil flow
path 43a.
[0032] In order for the oil to be supplied by the oil feeder 80,
the oil should be maintained at appropriate levels inside the
container 10. However, the level of oil may vary during operation
of the compressor 100. The variation of oil level may be an
absolute variation due to, for example, loss or leakage of oil, or
a temporary variation in which the oil level may temporarily
increase or decrease during operation based on changes in an
operational speed of the compressor 100. In either case, the oil
level should be maintained in an appropriate condition, for
example, within an acceptable range, during the operation of the
compressor to ensure normal operation. Accordingly, an oil level
detecting sensor 102 may be provided to detect the oil level inside
the container 10 in real time.
[0033] The oil level detecting sensor 102 may include a pair of
electrodes 102a, which may protrude inside the container 10. A
supporting plate 102b may be provided to support the pair of
electrodes 102a and allow them to pass through the container 10
into the compressor 100. The supporting plate 102b may be attached
to a side wall of the container 10 by, for example, welding or
another appropriate method of attaching. Further, the supporting
plate 102b may be attached to the container 10 so as to be flush
with an outer surface of the container 10. A flange 102c may be
formed that protrudes from an outer circumference of the supporting
plate 102b. A flange anchoring portion 16, which may have a
diameter greater than a diameter of the mounting hole 14, may be
formed at an outer circumference of the mounting hole 14. When the
supporting plate 102b is inserted into the mounting hole 14, the
flange 102c may be seated on the flange anchoring portion 16 and
may be attached to the container 10. Accordingly, the supporting
plate 102b may be mounted to the container 10 at a desired
position.
[0034] FIG. 3 is a flow chart of a method of operating the air
conditioner of FIG. 1. Referring to FIG. 3, once operation of the
plurality of compressors is initiated, the oil level H of each
compressor may first be detected, in step S01. Based on the
detection result, it may then be determined whether the oil level H
of each compressor is over a preset level for the respective
compressor, in step S02. If the oil level H of all of the
compressors is over the respective preset level, normal operation
of the plurality of compressors may be initiated, in step S07. If
the oil level H of some or all of the plurality of compressors is
not over the preset level, then a number of compressors may be
determined in which the oil level H is less than or equal to the
respective preset level, in step S03. If the number of compressors
having a relatively low oil level H is greater than a predetermined
number of compressors, for example, the number of compressors is
greater than one, then an oil collection operation may be
initiated, in step S08. When the number of compressors requiring
additional oil is two or more, it may be difficult to adjust the
oil level in each compressor to be over the preset levels without
an oil collection operation. Further, when the number of
compressors is two or more, a large amount of time may be required
to transfer oil between the plurality of compressors. In this case,
the oil collection operation may be required. The predetermined
number of compressors may be set to any number according to the
number of compressors included in the air conditioner.
[0035] The oil collecting operation may transfer oil remaining
inside the air conditioner, for example, in the foregoing
indoor/outdoor-side heat exchanger or pipes, to the compressor(s)
having a low oil level. During the oil collecting operation, the
expansion apparatus 160, 160', 160'' of each indoor unit and each
indoor-side heat exchanger may be fully opened, an operation of the
indoor unit may suspended, and a flow rate in the pipes may be
increased. The flow rate may be increased by operating a greater
number of compressors than during a normal operation or by
increasing an operational speed of one or more of the
compressors.
[0036] If the number of compressors in which the oil level H is
less than or equal to the respective preset level is determined to
be less than or equal to the predetermined number in step S03, for
example, the number of compressors is equal to one, the process may
move to step S04. In step S04, the oil levels H in the compressors
may be adjusted without performing an oil collecting operation. For
example, a solenoid valve of the compressor in which the oil level
H is greater than the preset level may be opened, and a solenoid
valve of the compressor in which the oil level H is less than the
preset level may be closed, in step S04. For example, referring to
FIG. 1, if the compressor 100 has a sufficient oil level and the
compressor 100'' has a relatively low oil level, the solenoid valve
126 may be opened and the solenoid valve 126'' may be closed.
[0037] With the solenoid valves configured as above, a normal
operation of the compressors may be carried out for a predetermined
period of time, for example, approximately five minutes, in step
S05. During the normal operation of the compressors, oil may be
collected from the compressor 100 having a sufficient oil level,
which may then be uniformly distributed and supplied to each
compressor through the first and the second suction pipes. However,
as the solenoid valve 112'' of the compressor 100'' having a
relatively low oil level is closed, oil is not collected from
compressor 100''. The oil level in the compressor 100'' may
therefore gradually increase above the preset level. Accordingly,
an oil level of a compressor having insufficient oil may be
increased above the preset level when a total amount of oil stored
in the air conditioner is sufficient.
[0038] However, it may be difficult to adjust the oil level of each
compressor over a desired level in spite of the foregoing process
when a total amount of oil remaining inside all of the compressors,
for example, a total amount of oil in the air conditioning system,
is insufficient to be redistributed. Thus, as previously described,
the normal operation may be carried out for the predetermined
period of time, for example, approximately 5 minutes, in step S05.
Thereafter, the oil levels H of the compressors may be checked
again, and if the oil level H of all of the compressors is over
each respective preset level, in step S06 the compressors may
return to normal operation, in step S06. Otherwise, if the oil
level H of all of the compressors is not above the respective
preset levels, the oil collecting operation may be performed, in
step S08.
[0039] FIG. 4 is a schematic diagram of an air conditioner
according to another embodiment. Referring to FIG. 4, the air
conditioner may temporarily store oil collected from each
compressor 100, 100', 100'' in an oil reservoir 128 through a first
oil return pipe 120, 120', 120''. The oil reservoir 128 may include
an oil level detecting sensor 128a that detects an oil level inside
the oil reservoir 128 and a valve 128b that controls a flow of oil
discharged from the oil reservoir 128. The oil reservoir 128 may
store oil exceeding a preset level received from each of the
compressors 100, 100', 100'', and may then supply the stored excess
oil to a compressor having a low oil level through the first
suction pipe 110 and the second suction pipes 112, 112', 112''.
[0040] FIG. 5 is a flow chart of a method of operating the air
conditioner of FIG. 4. After detecting an oil level H of each
compressor, in step S10, a number of compressors in which the oil
level H is lower than or equal to a respective preset level is
determined. If the number of compressors is less than or equal to a
predetermined number, for example, the predetermined number is one,
in step S11, then it may be determined whether all of the
compressors have sufficient amounts of oil, in step S12. If the oil
level H of all of the compressors is above the respective preset
level, then the compressors are operated in normal operation, in
step S16. If it is determined in step S12 that the oil level H of
all of the compressors is not over the respective preset level,
then a solenoid valve 126 of each compressor in which the oil level
H is greater than a respective preset level may be opened, and a
valve 126'' of the compressor in which H is less than or equal to
the desired level may be closed, in step S13.
[0041] A normal operation of the compressors may be carried out in
this state for a predetermined amount of time, for example, about
five minutes, in step S14. Then, oil collected from each of the
compressors having a sufficient amount of oil may be uniformly
distributed and supplied to all compressors through the first and
the second suction pipes. However, oil is not collected from a
compressor for which the solenoid valve is closed. Further, oil may
be collected again even if it is supplied to a compressor for which
the solenoid valve is open, thereby maintaining the oil level over
a preset level. Accordingly, the oil levels in each of the
compressors may be maintained over a preset level when the total
amount oil stored by the compressors is sufficient.
[0042] However, it may be difficult to adjust the oil level of a
compressor to be over a preset level in spite of this process when
the total amount of oil remaining inside the compressors is
insufficient. Thus, as previously described, a normal operation of
the compressors may be carried out for the predetermined period of
time, for example, approximately 5 minutes, in step S14. Then, the
oil level of each of the compressors may be checked again, and in
step S16, if the oil level H of all compressors is over each
respective preset level, in step S15, a normal operation may be
carried out. Otherwise, an oil collecting operation may be
performed, in step S20.
[0043] In step S11, if the number of the compressors having a
relatively low oil level (H is below respective preset level) is
greater than the predetermined number, for example, the
predetermined number is one then an oil level of the oil reservoir
(H.sub.R) may be detected, in step S17. After detecting the oil
level H.sub.R of the oil reservoir, the oil collecting operation
may be performed, in step S20, if the oil level H.sub.R of the oil
reservoir is lower than or equal to a preset level of the
reservoir, in step S18. Otherwise, if H.sub.R is greater than the
preset level, the reservoir valve 128b may opened, in step S19, and
the solenoid valves 126, 126', 126'' of the compressors may be
configured as previously described to increase the oil levels in
the compressors having oil levels below preset levels, in step
S13.
[0044] FIG. 6 is a schematic diagram of an air conditioner
according to another embodiment. Referring to FIG. 6, a plurality
of compressors 200, 200', 200'' may share one oil separator 230. An
oil level detecting sensor 231 that detects an oil level H.sub.S
inside the oil separator 230 may be provided in the oil separator
230. Further, a second oil return pipe 232 that supplies the oil
stored in the oil separator 230 to the compressors 200, 200', 200''
may be provided. The second oil return pipe 232 may be connected to
oil replenishing pipes 234, 234', 234'', which may be connected to
the second suction pipes 112, 112', 112'' of the compressors,
respectively. In addition, the oil replenishing pipes 234, 234',
234'' may be provided with valves 236, 236', 236'' that control the
flow of oil to each respective compressor 200, 200', 200''.
[0045] The valves 236, 236', 236'' may be switched according to a
detection result of corresponding oil level detecting sensors 102,
102', 102''. For example, if additional oil is not required in
compressors 200, 200' because the respective oil levels are greater
than a respective preset level, corresponding valves 236, 236' may
be closed. However, if additional oil is required in compressor
200'' because a corresponding oil level is less than a preset
level, valve 236'' may be opened to supply oil stored in the oil
separator 230 to compressor 200''.
[0046] FIG. 7 is a flow chart of a method of operating the air
conditioner of FIG. 6. After detecting an oil level H of each
compressor, in step S21, a number of compressors in which the oil
level H is lower than or equal to a respective preset level is
determined, in step S22. If the number of compressors is less than
or equal to a predetermined number, for example, the predetermined
number is one, then it is determined whether all of the compressors
have a sufficient amount of oil, in step S23. If the oil level H of
all of the compressors is above the respective preset levels, then
the compressors are operated in normal operation, in step S27. If
the oil level H of all of the compressors are not above the preset
levels, then the solenoid valve 236'' of the compressor in which H
is less than or equal to the preset level may be opened, and the
solenoid valve 236, 236' of each of the compressors in which H is
greater than the respective preset level may be closed, in step
S24.
[0047] Thereafter, normal operation may be carried out in this
state for a predetermined amount of time, for example, about five
minutes, in step S25. The oil stored in the oil separator 230 may
then be provided to the compressor 200'' having the insufficient
oil level during the predetermined amount of time. Then, the oil
level of all of the compressors may be checked again, and if the
oil level H of the all compressors is over each respective preset
level, in step S26, the compressors may return to normal operation,
in step S27. Otherwise, an oil collecting operation may be
performed, in step S30.
[0048] Returning to step S22, if the number of the compressors in
which the oil level H is less than or equal to the respective
preset level is greater than the predetermined number, for example,
the number of compressors is 2 or 3, then the oil level H.sub.S of
the oil separator 230 may be detected, in step S28. After detecting
the oil level H.sub.S, the oil collecting operation may be
performed, in step S30, if the oil level H.sub.S is lower than or
equal to a preset level for the oil separator 230, in step S29.
Otherwise, if the oil level H.sub.S is over the preset level, the
valves of each compressor may be configured to add oil to
compressors having an oil level H less than or equal to the
respective preset level, in step S24.
[0049] According to embodiments, an operating method for an air
conditioner having multiple compressors is provided which may
minimize an amount of time required to perform an oil collection
operation.
[0050] According to one embodiment, an operating method may be
provided for an air conditioner, which may include a plurality of
compressors, each of which may include a casing that may store oil
in an inner lower portion thereof and an oil level detecting device
that detects the oil level within the casing; at least one first
heat exchanger that intakes a working fluid from the plurality of
compressors; at least one expansion unit; at least one second heat
exchanger, through which the working fluid may pass after the first
heat exchanger; a first suction pipe, to which the working fluid
flows from the first or second heat exchanger; and a plurality of
second suction pipes, which may be branched out from the first
suction pipe and connected to each of the compressors. The method
may include detecting an oil level of each of the compressors;
distributing the oil in the compressor containing oil over a
desired level preset for each compressor toward the compressor
containing oil lower than a desired level preset for each
compressor via the first and the second suction pipes without
passing through the first and the second heat exchanger; and
performing an oil collecting operation in a case in which there may
be a compressor containing oil lower than a desired level preset
for each compressor after performing the distributing.
[0051] According to this embodiment, the oil may be supplied to the
compressors with a relatively lower oil level from a compressor
with a relatively higher oil level without performing an oil
collecting operation. Therefore, it may be possible to supply oil
to the compressor without stopping normal operation of the air
conditioner, which may minimize a number of the oil collecting
operations.
[0052] The distributing may be performed for a predetermined period
or until all of the compressors have the desired oil level.
However, there may be a limit as to an amount of time necessary to
distribute the oil when there is not enough oil in the compressors
to fill each compressor to a respective desired level preset for
each compressor with the oil from another compressor.
[0053] The oil collecting operation may be performed prior to the
distributing when a number of the compressors containing oil lower
than a desired level preset for each compressor is more than a
predetermined number. For example, when there is not enough oil in
the compressors to fill each compressor to a desired level preset
for each compressor with the oil supply between the compressors,
the oil distributing process may be cancelled, and then the oil
collecting operation may proceed.
[0054] Further, a first oil return pipe may be included that
connects an inside of the casing of each compressor to the first
suction pipe, and the oil in the compressor containing oil over a
desired level preset for each compressor may be supplied to the
first suction pipe via the first oil return pipe during the
distributing. The oil supplied to the first suction pipe may be
distributed to each of the compressors via the second suction pipe,
and by performing such steps repeatedly, the oil level in each of
the compressors may remain over a desired level preset for each
compressor.
[0055] Further, the first oil return pipe of the compressor
containing oil lower than a desired level preset for each
compressor may remain closed during the distributing. Accordingly,
the oil level may be recovered quickly to the desired level since
the oil in the compressor containing oil lower than a desired level
preset for each compressor may not be collected from the
compressor.
[0056] Additionally, at least one oil separator with a second oil
return pipe that connects the oil separator and the first suction
pipe may be included, and the oil collected in the oil separator
may be supplied to the first suction pipe via the second oil return
pipe. The oil separator may separate and store the oil from the
mixed working fluid discharged from the compressors, and the oil in
the oil separator may be supplied to the compressors to increase
the oil level.
[0057] Here, the first oil return pipe may be further included, and
it may be possible to increase the oil supply to the compressor by
connecting both of oil separator and first oil return pipe to the
first suction pipe. Further, additional oil storing devices, for
example, an oil reservoir, may be included, and the oil collected
from the compressors may be distributed via the oil storing
devices.
[0058] According to another embodiment, an operating method is
provided for an air conditioner including a plurality of
compressors, each of which may include a casing that stores oil in
on inner lower portion thereof, and an oil level detecting device
that detects the oil level within the casing; at least one oil
storage that stores the oil from the compressors; at least one
first heat exchanger that intakes a working fluid from the
plurality of compressors; at least one expansion unit; at least one
second heat exchanger, through which the working fluid may pass
after the first heat exchanger; a first suction pipe, to which the
working fluid flows from the first or second heat exchanger; and a
plurality of second suction pipes branched from the first suction
pipe and connected to each of the compressors. The method may
include detecting the oil level of each of the compressors and the
oil storage; supplying the oil in the oil storage or the
compressors containing oil over a desired level preset for each
compressor to the compressor containing oil lower than a desired
level preset for each compressor; and performing an oil collecting
operation when there is a compressor containing oil lower than a
desired level preset for each compressor after performing the step
of supplying.
[0059] The method may further include performing the oil collecting
operation when a number of the compressors containing oil lower
than a desired level preset for each compressor is over a
predetermined number and the oil level of the oil storage is lower
than a desired level for the oil storage.
[0060] Further, the oil in the oil storage may be supplied to the
compressor only when the oil level of the oil storage is over the
desired level for the oil storage. The oil storage may also include
at least one oil separator connected to the compressors.
Additionally, the supplying may be performed for a predetermined
period or until all of the compressors have the desired oil
level.
[0061] According to another embodiment, an operating method is
provided for an air conditioner which may include comprise at least
one compressor with an oil level detecting device; an oil
transferring device that transfers oil among the at least one
compressor; a plurality of heat exchangers and an expansion unit
that cooperate with the at least one compressor. The method may
include detecting the oil level of each of the compressors;
transferring the oil from the compressors with relatively higher
oil level to the compressors with a relatively lower oil level; and
performing an oil collecting operation when a number of the
compressors with the oil level lower than a desired level preset
for each compressor is greater than a predetermined number.
[0062] The method may further include performing the oil collecting
operation when a compressor containing oil lower than a desired
level preset for each compressor still remains even after
transferring the oil for a predetermined time.
[0063] According to another embodiment, an operating method is
provided for an air conditioner, which may include at least one
compressor with an oil level detecting unit; at least one oil
storage that may stores the oil from the at least one compressor;
an oil supplying device that supplies the oil of the oil storage to
the at least one compressor; a plurality of heat exchangers and
expansion units that cooperate with the at least one compressor.
The method may include detecting the oil level of each compressor
and the oil storage; supplying the oil from a compressor containing
oil over a desired level preset for each compressor or the oil
storage toward a compressor containing oil lower than a desired
level preset for each compressor; and performing an oil collecting
operation when a number of the compressors containing oil lower
than a desired level preset for each compressor is greater than a
predetermined number and the oil level of the oil storage is lower
than a desired level for the oil storage.
[0064] The method may further include supplying the oil from the
oil storage toward the compressor containing oil lower than a
desired level preset for each compressor when the number of the
compressors containing oil lower than a desired level preset for
each compressor is greater than the predetermined number and the
oil level of the oil storage is over the desired level for the oil
storage. According to this embodiment, a number of oil collecting
operations may be minimized by circulating the oil in the
compressors among the other compressors.
[0065] According to another embodiment, there is provided an
operating method for an air conditioner, the air conditioner
including a plurality of compressors, ea h of which includes a
casing that stores oil in an inner lower portion thereof and an oil
level detecting device that detects an oil level in the casing; at
least one first heat exchanger that intakes a working fluid from
the plurality of compressors; at least one expansion device; at
least one second heat exchanger, through which the working fluid
passes after passing through the at least one first heat exchanger;
a first suction pipe, through which the working fluid flows from
the at least one first heat exchanger or the at least one second
heat exchanger; and a plurality of second suction pipes branched
from the first suction pipe and then connected to each of the
compressors, wherein the method may include detecting an oil level
of each of the plurality of compressors; distributing oil in a
first compressor of the plurality of compressors containing oil
over a first preset level for the first compressor toward a second
compressor of the plurality of compressors containing oil lower
than a second preset level for the second compressor via the first
and the second suction pipes without passing through the at least
one first exchanger and the at least one second heat exchanger when
a number of the plurality of compressors containing oil lower than
the preset level for the respective compressor is less than or
equal to a predetermined number; and performing an oil collecting
operation if there exists a compressor containing oil lower than a
preset level for that compressor after performing the distributing
or if the number of the plurality of compressors containing oil
lower than the preset level for the respective compressor is
greater than the predetermined number.
[0066] The preset level of each of the plurality of compressors may
be all the same or all different. Alternatively, the preset level
of at least two of the plurality of compressors may be the same or
different.
[0067] The distributing may be performed for a predetermined period
of time, at predetermined time intervals, or until all of the
plurality of compressors have at least the preset level for the
respective compressor. Further, each of the plurality of
compressors may include a first oil return pipe that connects the
casing of the respective compressor to the first suction pipe, and
oil in the respective compressor containing oil over the preset
level for the respective compressor may be supplied to the first
suction pipe via the first oil return pipe during the distributing.
Furthermore, the first oil return pipe connected to a compressor
containing oil lower than a preset level for each compressor may
remain closed during the distributing.
[0068] The air conditioner may further include at least one oil
separator having a second oil return pipe that connects the oil
separator and the first suction pipe, and the oil collected in the
oil separator may be supplied to the first suction pipe via the
second oil return pipe during the step of distributing.
[0069] The at least one oil separator may receive a mixture of oil
and working fluid from at least one of the plurality of compressors
through an oil discharge pipe. The at least one oil separator may
also store the oil from the plurality of compressors and, if the
number of the plurality of compressors containing oil lower than
the preset level for the respective compressor is greater than the
predetermined number, the method may further include detecting an
oil level of the at least one oil separator; if the oil level of
the at least one oil separator is less than a preset level for the
at least one oil separator, performing the oil collecting
operation; and if the oil level of the at least one oil separator
is greater than or equal to the preset level, opening a valve that
allows the oil to flow into the compressor containing oil lower
than the preset level for the respective compressor.
[0070] The air conditioner may further include a plurality of oil
separators, and wherein each of the plurality of compressors may
discharge a mixture of oil and working fluid to a respective one of
the plurality of oil separators, wherein the distributing may
include distributing the oil stored in the at least one oil
separator toward the second compressor of the plurality of
compressors containing oil lower than the second preset level for
the second compressor.
[0071] The air conditioner may further include a first oil return
pipe that connects the casing of each compressor to the first
suction pipe, and the oil in the respective compressor containing
oil over a desired level preset for each compressor and the oil in
the oil separator may be supplied to the first suction pipe via the
first and the second oil return pipe during the distributing.
Additionally, the air conditioner may include at least one oil
reservoir that stores the oil from the plurality of compressors and
if the number of the plurality of compressors containing oil lower
than the preset level for the respective compressor is greater than
the predetermined number, the method may further include detecting
an oil level of the at least one oil reservoir; if the oil level of
the at least one reservoir is less than a preset level for the at
least one oil reservoir, performing the oil collecting operation;
and if the oil level of the at least one reservoir is greater than
or equal to the preset level of the at least one oil reservoir,
opening a reservoir valve of the at least one reservoir as part of
the distributing.
[0072] Each of the plurality of compressors may include a first oil
return pipe that connects the casing of the respective compressor
to the at least one oil reservoir, wherein oil in the respective
compressor containing oil over the preset level for the respective
compressor may be supplied to the at least one oil reservoir via
the first oil return pipe. The first oil return pipe connected to
the compressor containing oil lower than a preset level for each
compressor may remain closed during the distributing. The at least
one oil reservoir may function as an oil separator, wherein the oil
separator may receive a mixture of oil and working fluid from at
least one of the plurality of compressors through an oil discharge
pipe.
[0073] An operating method for an air conditioner may include a
plurality of compressors, each having an oil level detecting
device, an oil transferring device that transfers oil among the
plurality of compressors; and a plurality of heat exchangers and
expansion devices that cooperate with the plurality of compressors.
The method may further include detecting an oil level of each of
the plurality of compressors; transferring oil from at least one
compressor of the plurality of compressors with a relatively higher
oil level to at least one compressor of the plurality of
compressors with a relatively lower oil level when a number of the
plurality of compressors containing oil lower than the preset level
for the respective compressor is less than or equal to a
predetermined number; and performing an oil collecting operation if
a number of compressors containing oil lower than a preset level
for the respective compressor is greater than a predetermined
number.
[0074] The method may further include performing the oil collecting
operation when a compressor containing oil lower than the preset
level is detected after transferring the oil for a predetermined
period of time, wherein the transferring may include transferring
the oil without passing through the plurality of heat exchangers
and expansion devices that cooperate with the plurality of
compressors, and closing an oil return pipe connected to the
compressor containing oil lower than the preset level for the
respective compressor during the transferring.
[0075] An operating method for an air conditioner may include the
air conditioner that includes a plurality of compressors, each
having an oil level detecting device, an oil transferring device
that transfers oil among the plurality of compressors, and a
plurality of heat exchangers and expansion devices that cooperate
with the plurality of compressors, the method including detecting
an oil level of each of the plurality of compressors; transferring
oil from at least one compressor of the plurality of compressors
with a relatively higher oil level to at least one compressor of
the plurality of compressors with a relatively lower oil level when
a number of the plurality of compressors containing oil lower than
the preset level for the respective compressor is less than or
equal to a predetermined number; storing oil from at least one of
the plurality of compressors during a normal operation of the air
conditioner in at least one oil reservoir or at least one oil
separator; detecting an oil level of the at least one oil reservoir
or the at least one oil separator when the number of compressors
containing oil lower than the preset level for the respective
compressor is greater than the predetermined number; performing an
oil collecting operation when the oil level of the at least one oil
reservoir or the at least one oil separator is less than a preset
level for the at least one oil reservoir or the at least one oil
separator; and transferring the stored oil to the at least one
compressor of the plurality of compressors with the relatively
lower oil level when the oil level of the at least one oil
reservoir or the at least one oil separator is greater than or
equal to the preset level for the at least one oil reservoir or the
at least one oil seperator.
[0076] The at least one oil reservoir or the at least one oil
separator may include at least one oil separator, and wherein the
at least one oil separator receives a mixture of oil and working
fluid from at least one of the plurality of compressors through an
oil discharge pipe. The method may further include separating the
mixture of oil and working fluid at the at least one oil separator,
and storing the separated oil and transferring the separated
working fluid to the plurality of heat exchangers and expansion
devices that cooperate with the plurality of compressors. Further,
each of the plurality of compressors may include a valve that
controls a flow of the stored oil from the at least one oil
separator to each respective compressor, and wherein the method
further comprises opening the valve of the compressor containing
oil lower than the preset level during the transferring of the
stored oil.
[0077] The at least one oil reservoir or the at least one oil
separator may include at least one oil reservoir, wherein the at
least one oil reservoir may function as an oil separator. Each of
the plurality of compressors may include a valve that controls a
flow of oil in the oil return pipe from each respective compressor
to the at least one oil reservoir, and wherein the method may
further include closing the valve of the compressor containing oil
lower than the preset level during the transferring. Each of the
plurality of compressors may communicate with a respective one of a
plurality of oil separators. Further, the at least one oil
reservoir may receives oil from at least one of the plurality of
compressors through a respective oil return pipe that connects the
casing of each compressor to the at least one oil reservoir.
[0078] Any reference in this specification to "one embodiment," "an
embodiment," "example embodiment," etc., means that a particular
feature, structure, or characteristic described in connection with
the embodiment is included in at least one embodiment of the
invention. The appearances of such phrases in various places in the
specification are not necessarily all referring to the same
embodiment. Further, when a particular feature, structure, or
characteristic is described in connection with any embodiment, it
is submitted that it is within the purview of one skilled in the
art to effect such feature, structure, or characteristic in
connection with other ones of the embodiments.
[0079] Although embodiments have been described with reference to a
number of illustrative embodiments thereof, it should be understood
that numerous other modifications and embodiments can be devised by
those skilled in the art that will fall within the spirit and scope
of the principles of this disclosure. More particularly, various
variations and modifications are possible in the component parts
and/or arrangements of the subject combination arrangement within
the scope of the disclosure, the drawings and the appended claims.
In addition to variations and modifications in the component parts
and/or arrangements, alternative uses will also be apparent to
those skilled in the art.
* * * * *