U.S. patent application number 16/342533 was filed with the patent office on 2019-08-08 for air conditioner and control method thereof.
The applicant listed for this patent is GREE ELECTRIC APPLIANCES, INC, OF ZHUHAI. Invention is credited to Huaben LI, Haidong LIN, Si SUN, Chuanhua WANG, Feng WEI, Enquan ZHANG, Pengju ZHAO, Pu ZHAO.
Application Number | 20190242603 16/342533 |
Document ID | / |
Family ID | 58013531 |
Filed Date | 2019-08-08 |
United States Patent
Application |
20190242603 |
Kind Code |
A1 |
WEI; Feng ; et al. |
August 8, 2019 |
Air Conditioner and Control Method Thereof
Abstract
Provided are an air conditioner and a control method thereof.
The control method includes following steps: controlling a
compressor of an air conditioner to be in an operating state or a
shutdown state according to a superheat degree of injected vapor of
the compressor and a continuous duration of the superheat degree;
controlling the compressor to be in a shutdown state for
maintenance according to a number of shutdown times of the
compressor, so as to maintain a gas supply pipeline of the
compressor. By adopting such a configuration, an operating
condition of the compressor can be accurately and effectively
determined, which enables the compressor to be maintained timely,
thereby preventing the compressor from being damaged as a result of
operating in a severe condition, and enhancing operation
reliability of the compressor and the air conditioner.
Inventors: |
WEI; Feng; (Zhuhai, CN)
; LIN; Haidong; (Zhuhai, CN) ; SUN; Si;
(Zhuhai, CN) ; WANG; Chuanhua; (Zhuhai, CN)
; ZHANG; Enquan; (Zhuhai, CN) ; ZHAO; Pengju;
(Zhuhai, CN) ; ZHAO; Pu; (Zhuhai, CN) ; LI;
Huaben; (Zhuhai, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GREE ELECTRIC APPLIANCES, INC, OF ZHUHAI |
Zhuhai |
|
CN |
|
|
Family ID: |
58013531 |
Appl. No.: |
16/342533 |
Filed: |
September 26, 2017 |
PCT Filed: |
September 26, 2017 |
PCT NO: |
PCT/CN2017/103464 |
371 Date: |
April 17, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F24F 11/89 20180101;
F25B 41/00 20130101; F24F 2110/00 20180101; F25B 2700/21152
20130101; F25B 2500/06 20130101; F24F 2110/10 20180101; F24F 11/41
20180101; F24F 11/72 20180101; F24F 11/62 20180101; F25B 49/022
20130101; F25B 2500/04 20130101; F25B 2700/21151 20130101; F24F
11/30 20180101; F24F 1/00 20130101; F24F 11/86 20180101; F24F 11/64
20180101; F24F 11/70 20180101 |
International
Class: |
F24F 11/41 20060101
F24F011/41; F24F 11/86 20060101 F24F011/86 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 17, 2016 |
CN |
201610903627.7 |
Claims
1. A control method of an air conditioner, comprising: controlling
a compressor of an air conditioner to be in an operating state or a
shutdown state according to a superheat degree of injected vapor of
the compressor and a continuous duration of the superheat degree of
the injected vapor; and controlling the compressor to be in a
shutdown state for maintenance according to a number of shutdown
times of the compressor, wherein a gas supply pipeline of the
compressor is maintained.
2. The control method according to claim 1, wherein, the control
method comprises: controlling the compressor to be in the operating
state continuously when the number of the shutdown times of the
compressor is less than or equal to a first preset value; and
controlling the compressor to be in the shutdown state for
maintenance when the number of the shutdown times of the compressor
is greater than the first preset value.
3. The control method according to claim 1, wherein, the continuous
duration of the superheat degree further comprises a negative value
continuous duration; when the negative value continuous duration of
the superheat degree of the injected vapor reaches a second preset
value, and during the negative value continuous duration, an
exhaust temperature of the compressor remains less than a critical
value of the exhaust temperature of the compressor, and the
compressor is restored automatically to the operating state after
being shut down.
4. The control method according to claim 3, wherein, the continuous
duration of the superheat degree further comprises an offset value
continuous duration; if the offset value continuous duration, in
which the superheat degree of the injected vapor is greater than
the offset value of the superheat degree continuously, is less than
or equal to a third preset value, the offset value continuous
duration is included into the negative value continuous
duration.
5. The control method according to claim 4, wherein, the third
preset value is t, wherein, 0<t.ltoreq.60 s.
6. The control method according to claim 2, wherein, the first
preset value is N, wherein, 0<N.ltoreq.2.
7. The control method according to claim 1, wherein, in a heating
mode and/or in a cooling mode of the air conditioner, the
continuous duration of the superheat degree is tc, wherein,
tc=t1-t0, wherein, t1>to, and t0 is a time instant when the
superheat degree of the injected vapor begins to be less than an
offset value of the superheat degree; or tc=t1-t0+t, wherein, t1 is
a time instant when the superheat degree of the vapor injection
begins to be greater than the offset value of the superheat degree
after t0; t is a time period, in which the superheat degree of the
vapor injection is greater than the offset value of the superheat
degree; if t is greater than a fourth preset value, tc is reset to
zero and counted again from a next time instant when the superheat
degree of the vapor injection begins to be less than the offset
value of the superheat degree.
8. The control method according to claim 7, wherein, in a cooling
mode, when the air conditioner performs the defrost mode, the
continuous duration is reset to zero; and the reset continuous
duration is counted from a time instant when the superheat degree
of the injected vapor begins to be less than or equal to the offset
value of the superheat degree.
9. The control method according to claim 1, wherein, when the
compressor is in a shutdown protection state, maintenance on an
electronic expansion valve disposed in the gas supply pipeline of
the compressor is performed.
10. An air conditioner, wherein, the air conditioner is controlled
by the control method of claim 1, and the air conditioner
comprises: a compressor, a first heat exchanger, a second heat
exchanger, a gas supply device, which are in communication with
each other; and a gas supply pipeline, wherein: a first end of the
gas supply pipeline is in communication with an outlet end of the
first heat exchanger; a second end of the gas supply pipeline is in
communication with a gas supply port of the compressor; and at
least part of the gas supply pipeline performs heat exchange with
the gas supply device, to increase temperature of a refrigerant in
the gas supply pipeline.
11. The air conditioner according to claim 10, wherein, the gas
supply pipeline is provided with at least one of an electronic
expansion valve, a pressure sensor and a first temperature
sensor.
12. The air conditioner according to claim 10, wherein, a second
temperature sensor is arranged in a discharge pipeline of the
compressor.
13. The air conditioner according to claim 10, wherein, a third
temperature sensor is arranged in the gas supply pipeline; and the
third temperature sensor is disposed between an electronic
expansion valve and the gas supply device.
14. The air conditioner according to claim 10, wherein, the control
method comprises: controlling the compressor to be in the operating
state continuously when the number of the shutdown times of the
compressor is less than or equal to a first preset value; and
controlling the compressor to be in the shutdown state for
maintenance when the number of the shutdown times of the compressor
is greater than the first preset value.
15. The air conditioner according to claim 10, wherein, the
continuous duration of the superheat degree further comprises a
negative value continuous duration; when the negative value
continuous duration of the superheat degree of the injected vapor
reaches a second preset value, and during the negative value
continuous duration, an exhaust temperature of the compressor
remains less than a critical value of the exhaust temperature of
the compressor, and the compressor is restored automatically to the
operating state after being shut down.
16. The air conditioner according to claim 15, wherein, the
continuous duration of the superheat degree further comprises an
offset value continuous duration; if the offset value continuous
duration, in which the superheat degree of the injected vapor is
greater than the offset value of the superheat degree continuously,
is less than or equal to a third preset value, the offset value
continuous duration is included into the negative value continuous
duration.
17. The air conditioner according to claim 16, wherein, the third
preset value is t, wherein, 0<t.ltoreq.60 s.
18. The air conditioner according to claim 14, wherein, the first
preset value is N, wherein, 0<N.ltoreq.2.
19. The air conditioner according to claim 10, wherein, in a
heating mode and/or in a cooling mode of the air conditioner, the
continuous duration of the superheat degree is tc, wherein,
tc=t1-t0, wherein, t1>to, and t0 is a time instant when the
superheat degree of the injected vapor begins to be less than an
offset value of the superheat degree; or tc=t1-t0+t), wherein, t1
is a time instant when the superheat degree of the vapor injection
begins to be greater than the offset value of the superheat degree
after t0; t is a time period, in which the superheat degree of the
vapor injection is greater than the offset value of the superheat
degree; if t is greater than a fourth preset value, tc is reset to
zero and counted again from a next time instant when the superheat
degree of the vapor injection begins to be less than the offset
value of the superheat degree.
20. The air conditioner according to claim 19, wherein, wherein, in
a heating mode, when the air conditioner performs the defrost mode,
the continuous duration is reset to zero; and the reset continuous
duration is counted from a time instant when the superheat degree
of the injected vapor begins to be less than or equal to the offset
value of the superheat degree.
Description
FIELD
[0001] The present invention relates to the field of air
conditioner equipment, and particularly, to an air conditioner and
a control method thereof.
BACKGROUND
[0002] The air-source heat pump absorbs the low-temperature heat
energy from the air, which is transformed into high-temperature
heat energy through the compressor. As a highly efficient,
energy-saving and environmentally friendly heating technology, more
and more air-source heat pumps are used in China. Conventional
air-cooling air-source heat pumps most have a minimum environmental
temperature of -15.degree. C. for heating operations. In order to
broaden the heating operation range of the air-cooling air-source
heat pump, Enhanced Vapor Injection technology is often used. The
air-cooling heat pump using Enhanced Vapor Injection technology has
a heating operation range as low as -25.degree. C. to -30.degree.
C.
[0003] The throttling mechanism of an air-source heat pump
typically is an electronic expansion valve. The electronic
expansion valve is a throttling device, which controls the action
of the valve needle by controlling the voltage or current applied
to the expansion valve, to change the circulation area of the valve
port, thereby achieving automatic regulation of flow volume. A
common failure of the electronic expansion valve includes a jam,
which will result in no flow or uncontrolled flow in the relevant
flow path. The cause of the jam of the electronic expansion valve
is usually that there are impurities in the system. The jam of the
electronic expansion valve has a strong influence on the
reliability of the unit. When there is no flow in the event of a
jam, there will be a low-voltage protection or a high-temperature
exhaust protection, and the unit can usually be protected quickly,
thereby effectively protecting the compressor. When the flow is out
of control (larger number of steps) in the event of a jam, the jam
is usually difficult to be determined. If the unit cannot be
quickly protected and operates for a long time, the compressor will
be damaged, then it will be too late to find through inspection and
analysis that the damage of the compressor is caused by the jam of
the electronic expansion valve.
[0004] The electronic expansion valve for enhanced enthalpy
injection of the air-cooling heat pump system using enhanced vapor
injection technology is arranged in the sub pipeline of vapor
injection increasing enthalpy, which is located downstream of the
condenser, and performs functions of throttling and depressurizing
the refrigerant in the enhanced vapor injection loop. When the
electronic expansion valve for enhanced enthalpy injection is
jammed at 0B or at a small number of steps, the superheat degree of
the injected vapor will be a little larger, and the performance of
the unit will be reduced, and the effects of lowering the exhaust
temperature of the unit through increasing the injected vapor
amount will be affected. The long-term operation of vapor injection
will not affect the reliability of the compressor. If the exhaust
high temperature protection occurs, it can prompt the operation and
maintenance personnel of the unit to promptly analyze and check the
cause of the failure, and the compressor will not be damaged.
However, when the electronic expansion valve for enhanced enthalpy
injection is jammed at a larger number of steps, the refrigerant in
the enhanced vapor injection loop increases, which will cause
liquid injection to run and make the superheat degree of the vapor
injected to be negative. Long-term running of the liquid injection
will cause hydraulic hit in the compressor, and result in abrasion
due to insufficient lubrication as a result of diluted lubricant
film of the compressor. Therefore, it is necessary to timely judge
the failure behavior of the electronic expansion valve for enhanced
enthalpy injection when the electronic expansion valve is jammed at
a larger number of steps, to timely protect the unit and shut off
the compressor, to check and analyze the reason of the jam of the
electronic expansion valve for enhanced enthalpy injection, and to
replace the electronic expansion valve for enhanced vapor injection
in time, thus no serious after-sale damage of the compressor will
occur.
SUMMARY
[0005] The main objective of the present invention is to provide an
air conditioner and a control method thereof, so as to solve the
problem that the compressor in the prior art is easily damaged.
[0006] In order to realize the objective above, according to one
aspect of the present invention, a control method is provided. The
control method comprises following steps: controlling a compressor
of an air conditioner to be in an operating state or a shutdown
state according to a superheat degree of injected vapor of the
compressor and a continuous duration of superheat degree of the
injected vapor; and controlling the compressor to be in a shutdown
state for maintenance according to the number of shutdown times of
the compressor, so as to maintain a gas supply pipeline of the
compressor.
[0007] Further, the control method comprises: controlling the
compressor to be in the operating state continuously when the
number of shutdown times of the compressor is less than or equal to
a first preset value; and controlling the compressor to be in the
shutdown state for maintenance when the number of shutdown times of
the compressor is greater than the first preset value.
[0008] Further, the continuous duration of superheat degree further
comprises a negative value continuous duration; when the negative
value continuous duration of the superheat degree of the injected
vapor reaches a second preset value, and during the negative value
continuous duration, an exhaust temperature of the compressor
remains less than a critical value of the exhaust temperature of
the compressor, and the compressor is restored automatically to the
operating state after being shut down.
[0009] Further, the continuous duration of superheat degree further
comprises an offset value continuous duration; if the offset value
continuous duration, in which the superheat degree of the injected
vapor is greater than the offset value of the superheat degree
continuously, is less than or equal to a third preset value, the
offset value continuous duration is included into the negative
value continuous duration.
[0010] Further, the third preset value is t, wherein,
0<t.ltoreq.60 s.
[0011] Further, the first preset value is N, wherein,
0<N.ltoreq.2.
[0012] Further, in a heating mode or in a cooling mode of the air
conditioner, the continuous duration of superheat degree is tc,
wherein, tc=t1-t0, wherein, t1>to, and t0 is a time instant when
the superheat degree of the injected vapor begins to be less than
an offset value of the superheat degree; or tc=(t1-t0+t), wherein,
t1 is a time instant when the superheat degree of the vapor
injection begins to be greater than the offset value of the
superheat degree after t0; t is a time period, in which the
superheat degree of the vapor injection is greater than the offset
value of the superheat degree; if t is greater than a fourth preset
value, tc is reset to zero and counted again from a next time
instant when the superheat degree of the vapor injection begins to
be less than the offset value of the superheat degree.
[0013] Further, in a cooling mode, when the air conditioner
performs the defrost mode, the continuous duration is reset to
zero; and the reset continuous duration is counted from a time
instant when the superheat degree of the injected vapor begins to
be less than or equal to the offset value of the superheat
degree.
[0014] Further, when the compressor is in a shutdown protection
state, maintenance on an electronic expansion valve disposed in the
gas supply pipeline of the compressor is performed.
[0015] According to another aspect of the present invention, an air
conditioner is provided, which is the air conditioner described
above. The air conditioner comprises: a compressor, a first heat
exchanger, a second heat exchanger, a gas supply device, which are
in communication with each other; and a gas supply pipeline,
wherein: a first end of the gas supply pipeline is in communication
with an outlet end of the first heat exchanger; a second end of the
gas supply pipeline is in communication with a gas supply port of
the compressor; and at least part of the gas supply pipeline
performs heat exchange with the gas supply device, to increase
temperature of a refrigerant in the gas supply pipeline.
[0016] Further, the gas supply pipeline is provided with at least
one of an electronic expansion valve, a pressure sensor and a first
temperature sensor.
[0017] Further, a second temperature sensor is arranged in a
discharge pipeline of the compressor.
[0018] Further, a third temperature sensor is arranged in the gas
supply pipeline; and the third temperature sensor is disposed
between the outlet end of the first heat exchanger and the gas
supply device.
[0019] As for the technical solution of the control method of the
air conditioner, the control method includes controlling a
compressor of an air conditioner to be in an operating state or a
shutdown state according to a superheat degree of injected vapor of
the compressor and a continuous duration of superheat degree of the
injected vapor; and controlling the compressor to be in a shutdown
state for maintenance according to the number of shutdown times of
the compressor, so as to maintain a gas supply pipeline of the
compressor. Such a method can effectively judge the working
conditions of the compressor, so that the compressor can be timely
maintained and be protected from being damaged for operating under
severe working conditions, thereby improving the operation
reliability of the compressor and the air conditioner.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The accompanying drawings constituting a part of the present
application are provided to further make the present invention
understood. The illustrative embodiments of the present invention
and the description are used to explain the present invention, but
not intended to limit the present invention. In the drawings:
[0021] FIG. 1 is a schematic view illustrating an embodiment of an
air conditioner system in a heating mode according to the present
invention;
[0022] FIG. 2 is a schematic view illustrating an embodiment of the
air conditioner system shown in FIG. 1 in a cooling mode;
[0023] FIG. 3 is a block diagram illustrating the working process
of the compressor of the air conditioner shown in FIG. 1;
[0024] FIG. 4 is a block diagram illustrating the working process
of the air conditioner shown in FIG. 1 in the cooling mode and in
the heating mode respectively.
[0025] Wherein, the above figures include the following reference
numerals:
[0026] 10. compressor; 20. first heat exchanger; 30. second heat
exchanger; 40. gas supplying device; 50. gas supplying pipeline;
51. electronic expansion valve; 52. pressure sensor; 53. first
temperature sensor; 54. second temperature sensor.
DETAILED DESCRIPTION OF THE INVENTION
[0027] It should be specified that, the embodiments and the
features in the embodiments of the present invention may be
combined with each other when there is no conflict. The embodiments
of the present invention will be described in detail with reference
to the accompanying drawings.
[0028] It should be noted that, the terminology herein is used for
describing the specific embodiments, but not intended to limit the
illustrative embodiments of the present invention. The singular
terms herein are intended to include their plural unless specific
descriptions are provided in context. It should be also understood
that, the terms "include" and/or "comprise" in the description
refer to including the features, steps, operations, devices,
components, and/or combinations thereof.
[0029] It should be specified that the terms "first", "second",
etc. in the description, the claims and the drawings in the present
application are just used to distinguish similar objects, but not
used to describe a specific order or an order of priority. It
should be understood that such terms may be interchangeable under
appropriate conditions, such that the embodiments of the present
invention illustrated in the drawing or described herein can be
implemented, for example, in a sequence other than the sequences
illustrated or described herein. In addition, the terms "comprise",
"have" and any variations thereof are intended to cover a
non-exclusive inclusion. For example, a process, a method, a
system, a product, or a device that includes a series of steps or
units is not limited to those steps or units listed clearly, but
may include other steps or units, which are not clearly listed, or
which are inherent to such a process, a method, a product or a
device.
[0030] For the convenience of description, terms of spatial
relations such as "above", "over", "on a top surface", "upper",
etc., may be used herein to describe the spatial position
relationships of a device or a feature with other devices or
features shown in the drawings. It should be understood that the
terms of spatial relations are intended to include other different
orientations in use or operation in addition to the orientation of
the device described in the drawings. For example, if the device in
the drawings is placed upside down, the device described as "above
other devices or structures" or "over other devices or structures"
will be positioned as "below other devices or structures" or "under
other devices or structures". Thus, the exemplary term "above" may
include both "above" and "below". The device can also be positioned
in other different ways (rotating 90 degrees or at other
orientations), and the corresponding explanations for the
description of the spatial relations will be provided herein.
[0031] Now exemplary embodiments of the present invention will be
described in detail with reference to the accompanying drawings.
However, the exemplary embodiments may be implemented in different
forms and should not be interpreted to limit the present invention.
It should be understood that the embodiments are provided so that
the disclosure of the present application will be thorough and
complete, and the concepts of the exemplary embodiments will be
sufficiently disclosed to those skilled in the art. In the
drawings, the thicknesses of the layers and regions may be enlarged
for the sake of clarity, and as the same reference numerals denote
the identical devices, the description thereof is omitted.
[0032] As shown in FIGS. 1 through 4, according to an embodiment of
the present invention, a control method of the air conditioner is
provided.
[0033] Specifically, the control method of the air conditioner
includes controlling the compressor of the air conditioner to be in
an operating state or a shutdown state according to a superheat
degree of injected vapor of the compressor and a continuous
duration of superheat degree of the injected vapor; and controlling
the compressor to be in a shutdown state for maintenance according
to the number of shutdown times of the compressor, so as to
maintain a gas supply pipeline of the compressor.
[0034] In this embodiment, such a method can effectively judge the
working conditions of the compressor, so that the compressor can be
timely maintained and be protected from being damaged for operating
under severe working conditions, thereby improving the operation
reliability of the compressor and the air conditioner.
[0035] Wherein, the method further includes: the compressor is
controlled to be in an operating state when the number of shutdown
times of the compressor is less than or equal to the first preset
value; and the compressor is controlled to be in a shutdown state
for maintenance when the number of shutdown times of the compressor
is greater than the first preset value. Such a configuration can
effectively avoid a false judgment, which is made under the
conditions that the compressor shuts down itself under normal
working conditions, and that the shutdown will not cause damage to
the normal operation of the air conditioner and to the components
of the compressor. Such a control method can improve the operation
reliability of the air conditioner.
[0036] Further, the compressor is controlled to be in an operating
state continuously when the number of shutdown times of the
compressor is less than or equal to the first preset value; and the
compressor is controlled to be in a shutdown state for maintenance
when the number of shutdown times of the compressor is greater than
the first preset value. Such a configuration can effectively
detecting and controlling the working conditions of the compressor,
and timely maintaining the compressor and the pipelines of the air
conditioner.
[0037] Wherein, the first preset value is N, wherein
0<N.ltoreq.2. That is, when the compressor is shut down for the
second time or for the first time, it can be controlled to be in
the shutdown state for maintenance or in the operating state
continuously.
[0038] The continuous duration includes a negative value continuous
duration. When the negative value continuous duration of the
superheat degree of the injected vapor reaches a second preset
value, and during the negative value continuous duration, the
exhaust temperature of the compressor remains less than the
critical value of the exhaust temperature of the compressor, the
compressor is restored automatically to the operating state after
being shut down.
[0039] When the calculated negative value continuous duration of
the superheat degree of the injected vapor reaches the maximum
preset value, and during the negative value continuous duration of
the superheat degree of the injected vapor, the exhaust temperature
remains less than the critical value of the exhaust temperature,
then the compressor is restored automatically to the operating
state after being shut down. In calculating the negative value
continuous duration tc of the superheat degree of the injected
vapor, if a time period, in which the superheat degree of the
injected vapor is greater than the offset value of the superheat
degree, is less than or equal to the third preset value, the time
period is included into the negative value continuous duration of
the superheat degree. Such a configuration can effectively ensure
the operation reliability of the air conditioner, and avoid false
judgment caused by the working conditions and the like.
[0040] Wherein, the third preset value is t, wherein,
0<t.ltoreq.60 s. In this embodiment, t=60 s.
[0041] As shown in FIG. 3 and FIG. 4, in a heating mode and in a
cooling mode of the air conditioner, the continuous duration is
signed as tc, wherein tc is calculated as follows:
tc = { t 1 - t 0 , ( if TG .ltoreq. TP is kept till time instant t
1 ) t 1 - t 0 + t , ( if the continuous duration , in which TG >
TP , is less than or equal to t ) 0 , ( if the continuous duration
, in which TG > TP , is greater than t ) ##EQU00001##
[0042] Wherein, TG is the superheat degree of the injected vapor;
TP is the offset value of the superheat degree; t0 is the time
instant when the superheat degree of the injected vapor begins to
be less than or equal to the offset value of the superheat degree;
and t1 is the time instant when the superheat degree of the vapor
injection begins to be greater than the offset value of the
superheat degree after t0; it is known that t1>t0, that is, tc
is counted from the time instant t0 when TG.ltoreq.TP. If
TG.ltoreq.TP is kept till time instant t1, then the time (t1-t0) is
included into tc; if TG>TP at the time instant t1, and if the
continuous duration, in which TG>TP, is not greater than t, then
continue to calculate tc, namely, tc=(t1-t0+t); if TG>TP at the
time instant t1, and if the continuous duration, in which TG>TP,
is greater than t, then reset the calculated tc, and tc is counted
again from a next time instant when TG.ltoreq.TP; and afterwards,
tc is calculated according to the above method.
[0043] In the heating mode, when the air conditioner performs the
defrost mode, the continuous duration is reset to zero, and the
reset continuous duration is counted from the time instant when the
superheat degree of the injected vapor is less than or equal to the
offset value of the superheat degree.
[0044] Preferably, when the compressor is in the shutdown
protection state, maintenance on the electronic expansion valve
disposed in the gas supply pipeline of the compressor is performed,
which can improve the reliability of gas supply in the pipeline of
the compressor, thereby effectively improving the compression
performance of the compressor.
[0045] According to another aspect of the present invention, an air
conditioner is provided, which is the air conditioner in the above
embodiment. The air conditioner includes a compressor 10, a first
heat exchanger 20, a second heat exchanger 30 and a gas supply
device 40, which are in communication with each other. The first
end of the gas supply pipeline 50 is in communication with the
outlet end of the first heat exchanger 20; the second end of the
gas supply pipeline 50 is in communication with the gas supply port
of the compressor 10; and at least part of the gas supply pipeline
50 performs heat exchange with the gas supply device 40, to
increase the temperature of the refrigerant in the gas supply
pipeline 50. The operational reliability and the service life of
the air conditioner can effectively be improved.
[0046] As shown in FIGS. 1 and 2, the gas supply pipeline 50 is
provided with an electronic expansion valve 51, a pressure sensor
52 and a first temperature sensor 53. Wherein, the electronic
expansion valve 51 is configured to control the gas supply opening
in the gas supply pipeline 50; the pressure sensor 52 is configured
to detect the pressure in the gas supply pipeline 50; and the first
temperature sensor 53 is configured to detect the temperature in
the gas supply pipeline 50. The superheat degree of the injected
vapor of the compressor is calculated according to a conventional
computational method.
[0047] Further, in order to improve the accuracy of the calculated
result, a second temperature sensor 54 is further arranged in the
discharge pipeline of the compressor 10 to detect the exhaust
temperature at the discharge pipeline of the compressor. The nearer
the second temperature sensor 54 is to the gas vent of the
compressor, the more accurate the measurement is.
[0048] Of course, the gas supply pipeline 50 may not be provided
with the pressure sensor 52, and alternatively, a third temperature
sensor is arranged in the gas supply pipeline 50. The third
temperature sensor is disposed between the electronic expansion
valve 51 and the gas supply device 40.
[0049] A temperature sensor T3, namely the third temperature
sensor, is disposed in the pipeline entering the plate heat
exchanger namely the air supply device 40. The temperature sensor
T1, namely the first temperature sensor 53, is arranged at the
outlet of the plate heat exchanger and before the gas supply
opening of the compressor. The third temperature sensor and the
first temperature sensor 53 determine the conditions of liquid
injection, and at this time TG=(T1-T3) (usually, TG is controlled
to be 3.degree. C.-5.degree. C.). The judgment method, which
determines the state of the refrigerant of the enhanced vapor
injection according to the temperature difference between the gas
supply pipeline 50 entering and the gas supply pipeline 50 leaving
the heat exchanger in the enhanced vapor injection loop, is
applicable for a compressor system which is more resistant to the
liquid injection.
[0050] Specifically, in the enhanced vapor Injection system shown
in FIG. 1, whose throttling device is an electronic expansion
valve, a temperature sensor T1 and a pressure sensor P1 are
disposed between the outlet of the gas supply device 40 and the
inlet of the compressor, and a temperature sensor T2 is disposed in
the discharge pipe at the compressor outlet. The superheat degree
of the injected vapor is the difference between the temperature of
the enhanced vapor injection and the saturation temperature
corresponding to the pressure of the vapor injection, that is,
TG=T1-TB.sub.(p1).
[0051] The zero-degree celsius offset value of the superheat degree
is TP, and the value is from 0.5.degree. C. to 2.degree. C., which
is based on the accuracy of the temperature sensor T1 and the
actual situations. The critical value of the exhaust temperature is
TL. When the exhaust temperature is too high, it can be reduced by
increasing the vapor injection amount. However, the reduced exhaust
temperature should not be lower than the critical value of the
exhaust temperature. The critical value of the exhaust temperature
is determined by the compressor type or recommended by the
compressor manufacturer, and it is usually greater than 90.degree.
C.
[0052] The negative value continuous duration of the superheat
degree of the injected vapor is tc. The maximum preset negative
value continuous duration of the superheat degree of the injected
vapor is tMAX, which is matched and obtained through
experimentation. In this embodiment, tMAX=20 min.
[0053] When the unit operates normally, the control program
controls the electronic expansion valve according to the optimum
superheat degree (3.degree. C.-8.degree. C. in this embodiment) of
the vapor injection, and the steps of the electronic expansion
valve for the enhanced vapor injection is continuously adjusted, so
as to maintain the optimum superheat degree of the injected vapor.
When the electronic expansion valve for the vapor injection is
normal, the superheat degree of the injected vapor can be quickly
controlled to be within the optimal range, and usually, the
adjustment time is less than 15 minutes. At this time, the enhanced
vapor injection effect is optimum. When the electronic expansion
valve for the vapor injection is jammed at a larger number of
steps, liquid injection will occur. At this time, the failure
behavior is judged by the following processing method.
Specifically, after the compressor of the unit starts running, if
tc is equal to tMAX, and the exhaust temperature T2 is maintained
to be less than TL during this process (continuous duration tc),
then shut down the compressor of the corresponding system
immediately. After each of the first two shutdowns of the
compressor, the compressor is restored automatically to operate,
and after the compressor is shut down for the third time, the
compressor of the corresponding system is completely locked, and
the failure of the electronic expansion valve for enhanced vapor
injection is reported to warn the operation and maintenance
personnel of timely checking and analyzing, timely replacing the
electronic expansion valve for the enhanced vapor injection, so as
to protect the compressor. There are basically no false alarms in
this control method, the specific flow chart of which is shown in
FIG. 3.
[0054] The calculation method of the negative value continuous
duration tc of the superheat degree of the injected vapor is as
follows: it is known that t1>t0; operate in the cooling mode;
start the compressor; start to calculate tc after the electronic
expansion valve for enhanced vapor injection is turned on; tc is
counted from the time instant t0 when TG.ltoreq.TP; if TG.ltoreq.TP
is kept till the time instant t1, then the time (t1-t0) is included
into tc; if TG>TP at the time instant t1, and if the continuous
duration, in which TG>TP, is not greater than one minute, then
continue to calculate tc, namely, tc=(t1+-t0+60 s); if TG>TP at
the time instant t1, and if the continuous duration, in which
TG>TP, is greater than one minute, then reset the calculated tc,
and tc is counted from a next time instant when TG.ltoreq.TP; and
afterwards, tc is calculated according to the above method.
[0055] Operate in the heating mode; start the compressor; start to
calculate tc after the electronic expansion valve for enhanced
vapor injection is turned on; tc is counted from the time instant
t0 when TG.ltoreq.TP; if TG.ltoreq.TP is kept till the time instant
t1, then the time (t1 -t0) is included into tc; if TG>TP at the
time instant t1, and if the continuous duration, in which TG>TP,
is not greater than one minute, then continue to calculate tc,
namely, tc=(t1-t0+60 s); if TG>TP at the time instant t1, and if
the continuous duration, in which TG>TP, is greater than one
minute, then reset the calculated tc, and tc is counted from a next
time instant when TG.ltoreq.TP; and afterwards, tc is calculated
according to the above method. If the unit operating in the heating
mode enters the defrosting mode, the calculated tc is cleared; if
the unit operating in the defrosting mode enters the heating mode,
tc is counted again from the time instant when TG.ltoreq.TP, and
then calculate it according to the above method.
[0056] Accurately, fast and timely judge the failure of the
electronic expansion valve for enhanced vapor injection when it is
jammed at a larger number of steps; timely shut down the compressor
of the system, whose electronic expansion valve for enhanced vapor
injection has a failure; warn the operation and maintenance
personnel of timely analyzing and checking, and timely replacing
the electronic expansion valve for enhanced vapor injection, so as
to protect the compressor from severe damage. Reduce economic
losses and avoid severe after-sale failure of the compressor
damage.
[0057] What described above are preferable embodiments of the
present invention, and they are not intended to limit the present
invention. It will be understood by those skilled in the art that
various modifications and improvements can be made. All these
modifications, equivalent substitution and improvements made
without departing from the sprits and principles of the present
disclosure, are within the protection scope of the present
invention.
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