CN112728849A

CN112728849A - Freezing and refrigerating device and control method and control device thereof

Info

Publication number: CN112728849A
Application number: CN202110138642.8A
Authority: CN
Inventors: 张仕强; 张梓均; 陈敏; 吴梅彬; 李凝秀
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2021-02-01
Filing date: 2021-02-01
Publication date: 2021-04-30
Anticipated expiration: 2041-02-01
Also published as: CN112728849B

Abstract

The invention discloses a freezing and refrigerating device and a control method and a control device thereof. The freezing and refrigerating device comprises an outdoor unit, an air conditioner indoor unit, a refrigerated display cabinet and a refrigerated display cabinet, wherein the refrigerated display cabinet comprises at least two heat exchangers which are connected, and the outdoor unit is provided with a bypass pipeline; the first end of the bypass pipeline is connected to the exhaust port of the first compressor through a four-way valve, the first end of the bypass pipeline is also connected to an outdoor heat exchanger, the second end of the bypass pipeline is connected to the first port of the refrigerated display cabinet, and at least two heat exchangers can be connected to the first port of the refrigerated display cabinet in an on-off manner; in the defrosting mode, the exhaust port of the first compressor is communicated with the first port of the refrigeration display cabinet through a bypass pipeline, and at least two heat exchangers defrost alternately; and the exhaust port of the first compressor is communicated with the outdoor heat exchanger in the heating mode. In the defrosting mode, the refrigerant discharged by the first compressor directly enters the refrigeration display cabinet by utilizing the bypass pipeline, and the at least two heat exchangers alternately defrost to realize quick defrosting and ensure the refrigeration effect.

Description

Freezing and refrigerating device and control method and control device thereof

Technical Field

The invention relates to the technical field of freezing and refrigerating, in particular to a freezing and refrigerating device and a control method and a control device thereof.

Background

There is a conventional refrigerating and freezing apparatus in which an air conditioner indoor unit, a showcase, and a freezing showcase are connected in parallel to an outdoor unit. The refrigerating apparatus can switch a cooling mode, a heating mode and a heat recovery mode by controlling the four-way valve. However, since the refrigerated showcase is required to maintain a temperature of-18 ℃ or lower for a long period of time, the evaporation temperature of the refrigerated showcase is extremely low, and the heat exchanger (as an evaporator) thereof is liable to frost, causing a low heat exchange efficiency.

Aiming at the problem that the heat exchanger of the refrigeration display cabinet in the prior art is frosted, an effective solution is not provided at present.

Disclosure of Invention

The embodiment of the invention provides a freezing and refrigerating device and a control method and device thereof, which are used for at least solving the problem that a heat exchanger of a freezing showcase in the prior art frosts.

In order to solve the above technical problem, an embodiment of the present invention provides a freezing and refrigerating apparatus, including: the refrigeration display cabinet comprises an outdoor unit, an air conditioner indoor unit, a refrigeration display cabinet and a refrigeration display cabinet, wherein the refrigeration display cabinet comprises at least two heat exchangers which are connected with each other; in the defrosting mode, the air outlet of the first compressor is communicated with the first port of the refrigeration display cabinet through the bypass pipeline, and the at least two heat exchangers alternately defrost; and the exhaust port of the first compressor is communicated with the outdoor heat exchanger in the heating mode.

Optionally, a first reversing device is disposed at a first end of the bypass line, a first port of the first reversing device is connected to the four-way valve, a second port of the first reversing device is connected to the outdoor heat exchanger, and a third port of the first reversing device is connected to the first end of the bypass line.

Optionally, a first valve is arranged on a connecting pipeline between the first end of the bypass pipeline and the outdoor heat exchanger, and a second valve is arranged on the bypass pipeline.

Optionally, a third valve is further disposed on the bypass line, and the third valve is connected between the first reversing device and the second end of the bypass line, or the third valve is connected between the second valve and the second end of the bypass line.

Optionally, each of the at least two heat exchangers is correspondingly provided with a refrigeration showcase throttling device and a second reversing device; the refrigerated display case further comprises a second compressor, an air outlet of the second compressor being connected to an air inlet of the first compressor; the first end of each heat exchanger in the at least two heat exchangers is connected to the first end of a fourth valve through a corresponding freezer display case throttling device, and the second end of the fourth valve is connected to an air conditioner internal unit throttling device and a refrigerated display case throttling device; the second end of each heat exchanger in the at least two heat exchangers is connected to the first port of the corresponding second reversing device, the second port of the second reversing device is connected to the first port of the refrigerated display cabinet, and the third port of the second reversing device is connected to the suction port of the second compressor.

Optionally, any two heat exchangers in the at least two heat exchangers share the second reversing device, the second end of one heat exchanger in the at least two heat exchangers is connected to the first port of the corresponding second reversing device, the second port of the corresponding second reversing device is connected to the first port of the refrigerated display cabinet, the third port of the corresponding second reversing device is connected to the suction port of the second compressor, and the fourth port of the corresponding second reversing device is connected to the second end of another heat exchanger in the at least two heat exchangers.

Optionally, each of the at least two heat exchangers is correspondingly provided with a refrigeration showcase throttling device, a fifth valve and a sixth valve; the refrigerated display case further comprises a second compressor, an air outlet of the second compressor being connected to an air inlet of the first compressor; the first end of each heat exchanger in the at least two heat exchangers is connected to the first end of a fourth valve through a corresponding freezer display case throttling device, and the second end of the fourth valve is connected to an air conditioner internal unit throttling device and a refrigerated display case throttling device; the second end of each of the at least two heat exchangers is connected to the suction port of the second compressor through a respective fifth valve, and the second end of each heat exchanger is also connected to the first port of the refrigerated display cabinet through a respective sixth valve.

The embodiment of the invention also provides a control method of the freezing and refrigerating device, which is applied to the freezing and refrigerating device provided by the embodiment of the invention and comprises the following steps: receiving a defrosting instruction; the control bypass pipeline is communicated with an exhaust port of the first compressor and a first port of the refrigeration display cabinet; at least two heat exchangers of the freezing showcase are controlled to alternately defrost.

Optionally, if the bypass pipeline is provided with a first reversing device and a third valve, the bypass pipeline is controlled to communicate the exhaust port of the first compressor with the first port of the refrigeration display cabinet, including: adjusting the frequency of the first compressor to a preset reversing frequency; controlling the first reversing device to communicate the first port and the third port, and opening the third valve to enable the refrigerant to flow from the first compressor to the refrigeration display cabinet; the first port of the first reversing device is connected to a four-way valve, the third port of the first reversing device is connected to the first end of the bypass pipeline, and the third valve is connected between the first reversing device and the second end of the bypass pipeline.

Optionally, if the bypass line is provided with a first valve, a second valve and a third valve, the bypass line is controlled to communicate the exhaust port of the first compressor with the first port of the refrigerated display cabinet, including: closing the first valve, and opening the second valve and the third valve to enable the refrigerant to flow from the first compressor to the refrigerated display cabinet; wherein the first valve is disposed on a connection pipeline between a first end of the bypass pipeline and the outdoor heat exchanger, and the third valve is connected between the second valve and a second end of the bypass pipeline.

Optionally, controlling at least two heat exchangers of the refrigerated display cabinet to perform alternate defrosting comprises: closing a fourth valve, wherein a first end of the fourth valve is connected to the freezer display case throttling device corresponding to each heat exchanger, and a second end of the fourth valve is connected to an air conditioner internal unit throttling device and a refrigerated display case throttling device; when the current heat exchanger is defrosted, other heat exchangers in the at least two heat exchangers are controlled to refrigerate; and after the defrosting of the current heat exchanger is carried out for the first preset time, switching to the appointed heat exchanger for defrosting.

Optionally, if each of the at least two heat exchangers is correspondingly provided with a refrigeration showcase throttling device and a second reversing device, or each of the at least two heat exchangers is correspondingly provided with a refrigeration showcase throttling device and any two heat exchangers share the second reversing device, the at least two heat exchangers of the refrigeration showcase are controlled to perform defrosting alternately, including: for the heat exchanger for defrosting, controlling a second reversing device corresponding to the heat exchanger for defrosting to communicate the heat exchanger with the bypass pipeline and not communicate the heat exchanger with a second compressor, and controlling a refrigeration display cabinet throttling device corresponding to the heat exchanger for defrosting to adjust to the maximum opening; for the heat exchanger which does not defrost, controlling a second reversing device corresponding to the heat exchanger which does not defrost to communicate the heat exchanger with a second compressor and not communicate the heat exchanger with the bypass pipeline; under the condition that each heat exchanger is correspondingly provided with a second reversing device, a first port of the second reversing device is connected to a second end of the corresponding heat exchanger, a second port of the second reversing device is connected to a first port of the refrigeration display cabinet, and a third port of the second reversing device is connected to a suction port of the second compressor; under the condition that any two heat exchangers share the second reversing device, the first port of the second reversing device is connected to the second end of the corresponding one of the heat exchangers, the second port of the second reversing device is connected to the first port of the refrigeration display cabinet, the third port of the second reversing device is connected to the suction port of the second compressor, the fourth port of the second reversing device is connected to the second end of the corresponding other heat exchanger, and the two heat exchangers sharing the second reversing device do not defrost at the same time.

Optionally, if each heat exchanger of the at least two heat exchangers is correspondingly provided with a freezer display cabinet throttling device, a fifth valve and a sixth valve, the at least two heat exchangers of the freezer display cabinet are controlled to alternately defrost, including: for the heat exchanger for defrosting, closing the corresponding fifth valve, opening the corresponding sixth valve, and controlling the refrigeration display cabinet throttling device corresponding to the heat exchanger for defrosting to adjust to the maximum opening; for the heat exchanger which does not defrost, opening the corresponding fifth valve and closing the corresponding sixth valve; wherein the fifth valve is connected between the second end of the corresponding heat exchanger and the suction port of the second compressor, and the sixth valve is connected between the second end of the corresponding heat exchanger and the first port of the refrigerated display cabinet.

Optionally, after controlling the bypass line to communicate the exhaust port of the first compressor with the first port of the refrigerated display case, the method further comprises: controlling an outdoor fan to keep a starting state and monitoring the outlet temperature of an outdoor heat exchanger; and when the outlet temperature of the outdoor heat exchanger is kept unchanged for a second preset time, controlling the outdoor fan to stop working.

Optionally, after controlling the bypass line to communicate the exhaust port of the first compressor with the first port of the refrigerated display case, the method further comprises: and adjusting the frequency of the first compressor according to the discharge pressure of the first compressor so that the discharge pressure of the first compressor is not greater than a preset pressure.

The embodiment of the invention also provides a control device of the freezing and refrigerating device, which is applied to the freezing and refrigerating device provided by the embodiment of the invention and comprises the following components: the receiving module is used for receiving a defrosting instruction; the first control module is used for controlling the bypass pipeline to communicate the exhaust port of the first compressor with the first port of the refrigerated display cabinet; and the second control module is used for controlling at least two heat exchangers of the refrigeration display cabinet to alternately defrost.

Embodiments of the present invention also provide a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the method according to the embodiments of the present invention.

By applying the technical scheme of the invention, the bypass pipeline is arranged on the outdoor unit, and the high-temperature and high-pressure gaseous refrigerant discharged by the first compressor can directly enter the refrigeration display cabinet by utilizing the bypass pipeline in the defrosting mode, so that the quick defrosting of the heat exchanger of the refrigeration display cabinet is realized; the refrigeration showcase is internally provided with at least two connected heat exchangers, each heat exchanger can freely switch an evaporator and a condenser, so that the alternate defrosting of the heat exchangers in the refrigeration showcase is realized, the refrigeration temperature of the refrigeration showcase during defrosting can be effectively maintained, and the refrigeration effect during defrosting is ensured. And the refrigeration showcase is defrosted, the heating operation of an air conditioner indoor unit is not influenced, and the air conditioner indoor unit can continuously heat.

Drawings

Fig. 1 is a first schematic structural diagram of a freezing and refrigerating apparatus according to a first embodiment of the present invention;

fig. 2 is a schematic structural diagram of a refrigerating and freezing apparatus according to a first embodiment of the present invention;

fig. 3 is a schematic structural diagram of a refrigerating and freezing apparatus according to a first embodiment of the present invention;

fig. 4 is a schematic structural diagram of a refrigerating and freezing apparatus according to a first embodiment of the present invention;

fig. 5 is a flowchart of a control method of a refrigerating and freezing apparatus according to a second embodiment of the present invention;

fig. 6A to 6D are schematic diagrams (three heat exchangers) illustrating the flow direction of the refrigerant in the heating mode and the defrosting mode of the refrigeration and refrigeration apparatus according to the third embodiment of the present invention based on the connection mode 1 of the heat exchangers of the refrigeration showcase;

fig. 7 is a flowchart of a defrosting control corresponding to fig. 6A to 6D according to a third embodiment of the present invention;

fig. 8A to 8C are schematic diagrams (two heat exchangers) of refrigerant flow directions in the heating mode and the defrosting mode of the refrigeration and refrigeration apparatus according to the third embodiment of the present invention based on the connection mode 2 of the heat exchangers of the refrigeration showcase;

fig. 9 is a flowchart of defrost control corresponding to fig. 8A to 8C according to a third embodiment of the present invention;

fig. 10A to 10D are schematic diagrams (three heat exchangers) illustrating the flow direction of the refrigerant in the heating mode and the defrosting mode of the refrigeration and refrigeration apparatus according to the third embodiment of the present invention based on the connection mode 2 of the heat exchangers of the refrigerated showcase;

fig. 11 is a flowchart of a defrosting control corresponding to fig. 10A to 10D according to a third embodiment of the present invention;

fig. 12A to 12C are schematic refrigerant flow directions (two heat exchangers) of a refrigeration and cold storage apparatus according to a third embodiment of the present invention in a heating mode and a defrosting mode based on a connection mode 3 of heat exchangers of a refrigeration showcase;

fig. 13 is a flowchart of defrost control corresponding to fig. 12A to 12C according to a third embodiment of the present invention;

fig. 14A to 14D are schematic diagrams (three heat exchangers) illustrating the flow direction of the refrigerant in the heating mode and the defrosting mode of the refrigeration and refrigeration apparatus according to the third embodiment of the present invention based on the connection mode 3 of the heat exchangers of the refrigerated showcase;

fig. 15 is a flowchart of defrost control corresponding to fig. 14A to 14D according to a third embodiment of the present invention;

description of reference numerals:

an outdoor unit 1, an air conditioner indoor unit 2, a refrigerated showcase 3, and a refrigerated showcase 4;

a first compressor 111, a third compressor 112, a first four-way valve 121, a second four-way valve 122, a third four-way valve 123, an outdoor heat exchanger 13, an outdoor fan 14, a first flow divider 15, a first reversing device 16, a third valve 17, a first cut-off valve 181, a second cut-off valve 182, a third cut-off valve 183, a first valve 191, and a second valve 192;

the air conditioner indoor unit comprises an air conditioner indoor unit heat exchanger 21, an air conditioner indoor unit fan 22, a second flow divider 23 and an air conditioner indoor unit throttling device 24;

a refrigerated showcase heat exchanger 31, a refrigerated showcase fan 32, a third diverter 33, and a refrigerated showcase throttling device 34;

the refrigerating

showcase heat exchangers

411, 412 and … … 41n, the refrigerating showcase fan 42, the

fourth flow dividers

431, 432 and … … 43n, the refrigerating

showcase throttling devices

441, 442 and … … 44n, the second compressor 45, the

second reversing devices

461, 462 and … … 46n, the fourth valve 47, the

fifth valves

481, 482 and … … 48n and the

sixth valves

491, 492 and … … 49n are respectively arranged on the refrigerating showcase, and n represents the number of the heat exchangers of the refrigerating showcase.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

It should be noted that the steps illustrated in the flowcharts of the figures may be performed in a computer system such as a set of computer-executable instructions and that, although a logical order is illustrated in the flowcharts, in some cases, the steps illustrated or described may be performed in an order different than presented herein.

Example one

The present embodiment provides a refrigerating and freezing apparatus capable of simultaneously performing cooling of a refrigerator, cooling of a freezer, and indoor temperature adjustment. As shown in fig. 1 to 4, the freezing and refrigerating apparatus includes: outdoor unit 1, air conditioner indoor unit 2, refrigerated showcase 3, and refrigerated showcase 4. The refrigerated showcase 4 includes at least two heat exchangers connected to each other, and in order to distinguish between the air conditioner indoor unit heat exchanger and the refrigerated showcase heat exchanger, the at least two heat exchangers may be referred to as refrigerated showcase heat exchangers, and are denoted as 411, 412, and … … 41n, where n denotes the number of heat exchangers in the refrigerated showcase.

The outdoor unit 1 mainly includes: a first compressor 111, a third compressor 112, an outdoor heat exchanger 13, and an outdoor fan 14. The number of the first compressors 111 is at least one, and the suction ports of two or more first compressors may be selectively communicated by a four-way valve, and the discharge ports of two or more first compressors may be selectively communicated by a four-way valve. The third compressor 112 is used in a cooling mode, and the present application mainly relates to a heating mode and a defrosting mode, and does not relate to the cooling mode, so the operation of the related devices and the flow direction of the refrigerant in the cooling mode are not described in detail.

In the refrigeration mode, the air conditioner indoor unit supplies cold to the indoor space, and the refrigerated showcase and the freezing showcase cool the respective storehouses; in the heating mode, an air conditioner indoor unit heats the indoor space, and the refrigerated showcase and the freezing showcase cool the respective storehouses; in the defrosting mode, the air conditioner indoor unit heats the interior of the room, the refrigerated showcase cools the refrigerator, and the refrigerated showcase defrosts and cools the refrigerator.

The outdoor unit 1 is provided with a bypass line, a first end of the bypass line is connected to the exhaust port of the first compressor 111 through four-way valves (specifically, a first four-way valve 121 and a second four-way valve 122), the first end of the bypass line is further connected to the outdoor heat exchanger 13, a second end of the bypass line is connected to a first port of the refrigerated display cabinet, and at least two heat exchangers are connected to the first port of the refrigerated display cabinet in an on-off manner. The first port of the refrigerated display case is a connection port of the refrigerated display case to an outdoor unit, not shown.

In the defrosting mode, the exhaust port of the first compressor is communicated with the first port of the refrigeration showcase through the bypass pipeline, and at least two heat exchangers in the refrigeration showcase are used for defrosting alternately, so that the refrigerant flows from the compressor to the refrigeration showcase, the refrigeration showcase is defrosted by the high-temperature refrigerant, the heat exchangers which are not defrosted can supply cold, the refrigeration temperature of the refrigeration showcase during defrosting is effectively maintained, and the refrigeration effect during defrosting is guaranteed. The air outlet of the first compressor is communicated with the outdoor heat exchanger in the heating mode, so that when an air conditioner indoor unit supplies heat, the cooling requirements of the refrigeration display cabinet and the freezing display cabinet can be met through the work of the outdoor heat exchanger.

According to the refrigeration and cold storage device, the bypass pipeline is arranged on the outdoor unit, and in the defrosting mode, the high-temperature and high-pressure gaseous refrigerant discharged by the first compressor can directly enter the refrigeration showcase by using the bypass pipeline, so that the rapid defrosting of the heat exchanger of the refrigeration showcase is realized; the refrigeration showcase is internally provided with at least two connected heat exchangers, each heat exchanger can freely switch an evaporator and a condenser, so that the alternate defrosting of the heat exchangers in the refrigeration showcase is realized, the refrigeration temperature of the refrigeration showcase during defrosting can be effectively maintained, and the refrigeration effect during defrosting is ensured. And the refrigeration showcase is defrosted, the heating operation of an air conditioner indoor unit is not influenced, and the air conditioner indoor unit can continuously heat.

Fig. 1 and 2 show two connection modes of the bypass line, which are described below.

Referring to fig. 1, a first reversing device 16 is disposed on the bypass line, and specifically, a first reversing device 16 is disposed at a first end of the bypass line. The first reversing device may be a four-way valve. A first port of the first reversing device 16 is connected to a four-way valve (specifically, a first four-way valve 121), a second port of the first reversing device 16 is connected to the outdoor heat exchanger 13, and a third port of the first reversing device is connected to a first end of the bypass line. In the defrosting mode, the first reversing device 16 is controlled to enable the air outlet of the first compressor 111 to be communicated with the first port of the refrigeration showcase through the bypass pipeline, the flow direction of the refrigerant is changed, and therefore the high-temperature and high-pressure refrigerant discharged by the first compressor 111 can enter the heat exchanger of the refrigeration showcase, and defrosting is achieved.

In fig. 1, a third valve 17 may also be provided on the bypass line, the third valve 17 being connected between the first reversing device 16 and the second end of the bypass line. In the defrosting mode, the third valve 17 is opened to ensure that the refrigerant can flow into the refrigeration display cabinet from the first compressor; in other operation modes except the defrosting mode, the third valve 17 is closed, so that the refrigerant can flow correctly. The third valve 17 may be a valve element having an opening and closing function, such as a shutoff valve or a solenoid valve.

Referring to fig. 2, a first valve 191 is provided on a connection line between the first end of the bypass line and the outdoor heat exchanger 13, and a second valve 192 is provided on the bypass line. The first valve and the second valve may be valve elements having an opening and closing function, such as a shut-off valve and a solenoid valve. In the defrosting mode, the first valve 191 and the second valve 192 communicate the exhaust port of the first compressor 111 with the first port of the refrigeration showcase through the bypass line, and the refrigerant flow direction is changed, so that the high-temperature and high-pressure refrigerant discharged by the first compressor 111 can enter the heat exchanger of the refrigeration showcase, thereby defrosting.

In fig. 2, a third valve 17 may also be provided on the bypass line, the third valve 17 being connected between the second valve 192 and the second end of the bypass line. In the defrosting mode, the third valve 17 is opened to ensure that the refrigerant can flow into the refrigeration display cabinet from the first compressor; in other operation modes except the defrosting mode, the third valve 17 is closed, so that the refrigerant can flow correctly. The third valve 17 may be a valve element having an opening and closing function, such as a shutoff valve or a solenoid valve.

Refrigerated display case 4 can also include: and a second compressor 45, wherein the exhaust port of the second compressor 45 is connected to the suction port of the first compressor 111, and the suction port of the second compressor 45 can be connected to the heat exchanger in the refrigerated showcase in an on-off manner. Since the evaporation temperature required by the refrigerated showcase 4 is low and the corresponding evaporation pressure is low, the second compressor 45 mainly performs a supercharging function, and when the refrigerated showcase is used to cool a refrigerator normally, the outlet pressure of the heat exchanger of the refrigerated showcase is increased to be equivalent to the outlet pressure of the heat exchanger 31 of the refrigerated showcase, and the refrigerant is merged into the first compressor 111.

The following describes a specific connection mode of the heat exchanger of the refrigerated showcase with reference to the accompanying drawings.

Connection mode of heat exchanger of refrigeration showcase 1:

referring to fig. 1 and 2, a refrigerated display case throttling device and a second reversing device are provided for each of at least two heat exchangers of the refrigerated display case. Specifically, a first end of each heat exchanger is connected to a first end of a fourth valve 47 through a respective corresponding refrigerated display case throttling device, and a second end of the fourth valve 47 is connected to the indoor air conditioner throttling device 24 and the refrigerated display case throttling device 34. The second end of each heat exchanger is connected to the first port of a respective second reversing device, the second port of which is connected to the first port of the refrigerated display cabinet 4 and the third port of which is connected to the suction inlet of the second compressor 45.

The second reversing device can be a four-way valve, and the fourth port of the second reversing device is suspended and is not connected with any device. The fourth valve is opened under the heating mode, guarantees that the refrigerant that the air conditioner indoor set flows out can enter into the refrigeration show case and carry out the cooling, and the fourth valve is closed under the defrosting mode to the cooperation is controlled the operation and is guaranteed that the refrigeration show case can supply cold in the defrosting.

Through the second reversing device, each heat exchanger in the refrigeration display cabinet can be freely switched between the evaporator and the condenser, and can be used as the condenser to defrost or used as the evaporator to refrigerate, so that the alternate defrosting of the heat exchangers in the refrigeration display cabinet is realized, the refrigeration temperature of the refrigeration display cabinet during defrosting can be effectively maintained, and the refrigeration effect during defrosting is ensured.

Connection mode of heat exchanger of refrigeration showcase 2:

as a preferred embodiment of the connection mode 1 of the heat exchangers of the refrigeration showcase, any two heat exchangers in at least two heat exchangers of the refrigeration showcase can share the second reversing device, so that the number of devices and the occupied space are saved.

Specifically, the second end of one of the at least two heat exchangers is connected to the first port of the corresponding second reversing device, the second port of the corresponding second reversing device is connected to the first port of the refrigerated display cabinet, the third port of the corresponding second reversing device is connected to the suction port of the second compressor, and the fourth port of the corresponding second reversing device is connected to the second end of the other of the at least two heat exchangers.

That is to say, in this embodiment, the fourth port of the shared second reversing device is not suspended, and the two heat exchangers are respectively connected to the first port and the fourth port of the same second reversing device, so as to implement the sharing of the second reversing device.

Illustratively, the refrigerated display case includes n heat exchangers, and in the case where any two heat exchangers share the second reversing device, if n is even, a minimum of n/2 second reversing devices can be used, and if n is odd, a minimum of n/2+1 second reversing devices can be used.

Referring to fig. 3, the

heat exchangers

411 and 412 share the second reversing device 461, m represents the number of second reversing devices used in the case of sharing the second reversing device, and m is smaller than n.

Connection mode of heat exchanger of refrigeration showcase 3:

referring to fig. 4, a refrigerated display case throttling device, a fifth valve and a sixth valve are provided for each of at least two heat exchangers of the refrigerated display case. Specifically, a first end of each heat exchanger is connected to a first end of a fourth valve 47 through a respective corresponding refrigerated display case throttling device, and a second end of the fourth valve 47 is connected to the indoor air conditioner throttling device 24 and the refrigerated display case throttling device 34. The second end of each heat exchanger is connected to the suction of the second compressor 45 through a respective fifth valve and is also connected to the first port of the refrigerated display cabinet 4 through a respective sixth valve.

The fifth valve and the sixth valve may be valve elements having an opening and closing function, such as a shut-off valve and a solenoid valve. The fourth valve is opened under the heating mode, guarantees that the refrigerant that the air conditioner indoor set flows out can enter into the refrigeration show case and carry out the cooling, and the fourth valve is closed under the defrosting mode to the cooperation is controlled the operation and is guaranteed that the refrigeration show case can supply cold in the defrosting.

Through the fifth valve and the sixth valve, each heat exchanger in the refrigeration display cabinet can be freely switched between the evaporator and the condenser, and can be used as the condenser for defrosting or used as the evaporator for refrigerating, so that the alternate defrosting of the heat exchangers in the refrigeration display cabinet is realized, the refrigerating temperature of the refrigeration display cabinet during defrosting can be effectively maintained, and the refrigerating effect during defrosting is ensured.

While the above description describes two ways of connecting the bypass line and three ways of connecting the heat exchangers of the refrigerated display case, it will be appreciated that the ways of connecting the bypass line and the heat exchangers of the refrigerated display case can be combined arbitrarily to form a complete refrigerated refrigeration apparatus.

The refrigerated display case 4 can also comprise a refrigerated display case fan 42, and when a heat exchanger is arranged in the refrigerated display case for refrigerating, the refrigerated display case fan 42 is kept in an open state to ensure the heat exchange effect.

The throttle devices (24, 34, 441-44 n) in the present embodiment may be electronic expansion valves, thermostatic expansion valves, throttle valves, capillary tubes, and the like.

Example two

The present embodiment provides a method for controlling a freezing and refrigerating apparatus, which can be applied to the freezing and refrigerating apparatus described in the first embodiment, as shown in fig. 5, the method includes the following steps:

s501, receiving a defrosting instruction.

S502, controlling a bypass pipeline to communicate an exhaust port of the first compressor with a first port of the refrigerated display case.

And S503, controlling at least two heat exchangers of the refrigeration showcase to alternately defrost.

In the control method of the embodiment, in the defrosting mode, the high-temperature and high-pressure gaseous refrigerant discharged by the first compressor can directly enter the refrigeration showcase by using the bypass pipeline, and at least two heat exchangers of the refrigeration showcase are controlled to carry out alternate defrosting, so that the quick defrosting of the heat exchangers of the refrigeration showcase is realized, the refrigeration temperature of the refrigeration showcase during defrosting can be effectively maintained, and the refrigeration effect during defrosting is ensured. And the refrigeration showcase is defrosted, the heating operation of an air conditioner indoor unit is not influenced, and the air conditioner indoor unit can continuously heat.

If be provided with first switching-over device and third valve on the bypass pipeline, control bypass pipeline intercommunication first compressor's gas vent and the first port of freezing show case, include: adjusting the frequency of the first compressor to a preset reversing frequency; controlling the first reversing device to communicate the first port and the third port and opening the third valve to enable the refrigerant to flow from the first compressor to the refrigeration display cabinet; the first port of the first reversing device is connected to the four-way valve, the third port of the first reversing device is connected to the first end of the bypass pipeline, and the third valve is connected between the first reversing device and the second end of the bypass pipeline. The preset reversing frequency is specific to the first reversing device, the first reversing device has a specific frequency during reversing, and reversing is performed at the specific frequency, so that the noise is good and the reversing success rate is high. In this embodiment, based on the bypass line structure shown in fig. 1, the flow direction of the refrigerant is changed by controlling the first reversing device and the third valve, so that the switching between the defrosting mode and the heating mode is realized.

If be provided with first valve, second valve and third valve on the bypass pipeline, control bypass pipeline intercommunication first compressor's the gas vent and the first port of freezing show case, include: closing the first valve, and opening the second valve and the third valve to enable the refrigerant to flow from the first compressor to the refrigeration showcase; the first valve is arranged on a connecting pipeline between the first end of the bypass pipeline and the outdoor heat exchanger, and the third valve is connected between the second valve and the second end of the bypass pipeline. In this embodiment, based on the bypass line structure shown in fig. 2, the flow direction of the refrigerant is changed by controlling the first valve, the second valve, and the third valve, so that the switching between the defrosting mode and the heating mode is realized.

In one embodiment, controlling at least two heat exchangers of a refrigerated display case for a cyclical defrost includes: closing a fourth valve, wherein the first end of the fourth valve is connected to the freezer showcase throttling device corresponding to each heat exchanger, and the second end of the fourth valve is connected to the air conditioner internal unit throttling device and the refrigerated showcase throttling device; when the current heat exchanger is defrosted, other heat exchangers in the at least two heat exchangers are controlled to refrigerate; and after the defrosting of the current heat exchanger is carried out for the first preset time, switching to the appointed heat exchanger for defrosting.

The number of the heat exchangers defrosting at the same time can be one or more, and at least two heat exchangers of the refrigeration showcase can perform alternate defrosting according to a preset sequence, for example, the refrigeration showcase comprises 3 heat exchangers, which are recorded as A, B, C, and the preset sequence can be A, B, C, that is, the heat exchanger a performs defrosting first, when the defrosting of the heat exchanger a reaches a first preset time, the heat exchanger a is switched to the heat exchanger B to perform defrosting, and when the defrosting of the heat exchanger B reaches the first preset time, the heat exchanger C is switched to perform defrosting. The designated heat exchanger means one or more heat exchangers that defrost after the current heat exchanger in a preset order.

In the embodiment, the fourth valve is closed in the defrosting mode, so that the refrigerant cannot enter the refrigeration showcase from the air conditioner internal unit and the refrigeration showcase, and meanwhile, the defrosting and the refrigerating in the refrigeration showcase are simultaneously carried out by matching with the communication control of the heat exchanger in the refrigeration showcase, so that the refrigerating effect of the refrigeration showcase is ensured while defrosting.

For the

connection mode

1 or 2 of the refrigerated showcase heat exchanger in the first embodiment, if each of the at least two heat exchangers is correspondingly provided with a refrigerated showcase throttling device and a second reversing device, or each of the at least two heat exchangers is correspondingly provided with a refrigerated showcase throttling device and any two heat exchangers share the second reversing device, the method for controlling the at least two heat exchangers of the refrigerated showcase to alternately defrost includes:

for the heat exchanger for defrosting, controlling a second reversing device corresponding to the heat exchanger for defrosting to be communicated with the heat exchanger and the bypass pipeline and not to be communicated with the heat exchanger and a second compressor, and controlling a throttling device of the refrigeration display cabinet corresponding to the heat exchanger for defrosting to be adjusted to the maximum opening degree; wherein, the communication of the heat exchanger and the bypass pipeline is equivalent to the communication of the heat exchanger and the first port of the refrigeration display cabinet;

for the heat exchanger which does not defrost, controlling a second reversing device corresponding to the heat exchanger which does not defrost to communicate the heat exchanger with a second compressor and not communicate the heat exchanger with a bypass pipeline; the refrigeration showcase throttling device corresponding to the heat exchanger which does not defrost is controlled according to the control logic for refrigerating;

under the condition that each heat exchanger is correspondingly provided with a second reversing device, a first port of each second reversing device is connected to a second end of the corresponding heat exchanger, a second port of each second reversing device is connected to a first port of the refrigeration display cabinet, and a third port of each second reversing device is connected to a suction port of the second compressor;

in the case that any two heat exchangers share the second reversing device, the first port of the second reversing device is connected to the second end of the corresponding one of the heat exchangers, the second port of the second reversing device is connected to the first port of the refrigerated display cabinet, the third port of the second reversing device is connected to the suction port of the second compressor, the fourth port of the second reversing device is connected to the second end of the corresponding other heat exchanger, and the two heat exchangers sharing the second reversing device do not defrost at the same time.

According to the embodiment, the second reversing device is communicated and controlled, so that the heat exchangers in the refrigeration showcase can be alternately defrosted, the refrigeration temperature of the refrigeration showcase during defrosting can be effectively maintained, and the refrigeration effect during defrosting is ensured.

For the heat exchanger connection mode 3 in the first embodiment, if each of the at least two heat exchangers is correspondingly provided with the freezer display cabinet throttling device, the fifth valve and the sixth valve, the at least two heat exchangers of the freezer display cabinet are controlled to perform the alternate defrosting, which includes:

for the heat exchanger for defrosting, closing the corresponding fifth valve, opening the corresponding sixth valve, and controlling the refrigeration display cabinet throttling device corresponding to the heat exchanger for defrosting to adjust to the maximum opening;

for the heat exchanger which does not defrost, opening the corresponding fifth valve and closing the corresponding sixth valve; the refrigeration showcase throttling device corresponding to the heat exchanger which does not defrost is controlled according to the control logic for refrigerating;

and the fifth valve is connected between the second end of the corresponding heat exchanger and the suction port of the second compressor, and the sixth valve is connected between the second end of the corresponding heat exchanger and the first port of the refrigerated display cabinet.

In the embodiment, the fifth valve and the sixth valve are controlled, so that the heat exchangers in the refrigeration showcase can be alternately defrosted, the refrigeration temperature of the refrigeration showcase during defrosting can be effectively maintained, and the refrigeration effect during defrosting is ensured.

Considering that when the heating mode is changed into the defrosting mode, the outdoor heat exchanger is still in a high-temperature and high-pressure state, the refrigeration showcase is in an ultra-low-pressure state, and the refrigerant flows from a high-pressure side to a low-pressure side, so that the refrigerant at the outlet of the outdoor heat exchanger enters the heat exchanger of the refrigeration showcase, and at the moment, the refrigerant at both ends of the refrigeration showcase enters the high-pressure refrigerant, circulation is easy to be unsmooth, the heat exchange amount is reduced, and the defrosting progress is hindered, therefore, in one embodiment, after the bypass pipeline is controlled to communicate the exhaust port of the first compressor and the: controlling an outdoor fan to keep a starting state and monitoring the outlet temperature of an outdoor heat exchanger; and when the outlet temperature of the outdoor heat exchanger is kept unchanged for the second preset time, the outlet temperature of the outdoor heat exchanger is stable, and the outdoor fan is controlled to stop working. The embodiment keeps the outdoor fan on when the defrosting mode is just started, so that the heat energy of the outdoor heat exchanger can be quickly discharged to the outside, and the defrosting speed of the heat exchanger of the refrigeration showcase is increased.

In one embodiment, after controlling the bypass line to communicate the discharge of the first compressor with the first port of the refrigerated display case, the method further comprises: and adjusting the frequency of the first compressor according to the discharge pressure of the first compressor so that the discharge pressure of the first compressor is not more than the preset pressure. When the heating mode is changed into the defrosting mode, the pressure of the condensing side generally rises, and at the moment, the operation frequency of the first compressor is adjusted according to the exhaust pressure, so that the reliability problem (such as overhigh pressure) can be avoided, and the reliable operation of the freezing and refrigerating device is ensured.

It should be noted that the control operation of the outdoor fan, the adjustment operation of the frequency of the first compressor, and the alternate defrosting control operation of the freeze showcase heat exchanger can be performed simultaneously.

EXAMPLE III

The following describes the above-mentioned freezing and refrigerating apparatus and the control method thereof in detail with reference to fig. 6A to 15, however, it should be noted that this embodiment is only for better describing the present application and should not be construed as limiting the present application. The same or corresponding terms as those of the above-described embodiments are explained, and the description of the present embodiment is omitted.

(1) Aiming at the situation of the connection mode 1 of the heat exchanger of the refrigeration showcase

In the present embodiment, the flow direction of the refrigerant in the heating mode and the defrosting mode will be described by taking the refrigeration showcase including three heat exchangers (411, 412, and 413) as an example.

As shown in fig. 6A, in the heating mode, the refrigerant discharged from the first compressor 111 is branched. A part of refrigerant enters the air conditioner indoor unit 2 through the first four-way valve 121 (the first four-way valve 121 is in a power-down state, that is, the port connected with the heat exchanger 21 of the air conditioner indoor unit is communicated with the port connected with the exhaust port of the first compressor 111, and the port connected with the second four-way valve 122 is communicated with the port connected with the first reversing device 16), and in the air conditioner indoor unit 2, the refrigerant sequentially passes through the heat exchanger 21 (serving as a condenser) of the air conditioner indoor unit, the second flow divider 23 and the throttling device 24 of the air conditioner indoor unit, at this time, the fan 22 of the air conditioner indoor unit. The other part of the refrigerant enters the outdoor heat exchanger 13 (acting as a condenser) through the first reversing device 16 (the first reversing device 16 is in a power-on state, that is, the first four-way valve 121 is communicated with the outdoor heat exchanger 13, and the first four-way valve 121 is not communicated with the bypass pipeline), and passes through the first flow divider 15. Then, the two refrigerants are merged and split again. A portion of the refrigerant enters the refrigerated display case 3, and in the refrigerated display case 3, the refrigerant passes through a refrigerated display case throttling device 34, a third flow divider 33, and a refrigerated display case heat exchanger 31 (acting as an evaporator) in this order, at which time a refrigerated display case fan 32 is activated and the refrigerated display case throttling device 34 is opened. The other part of the refrigerant enters the freezing showcase 4, in the freezing showcase 4, the refrigerant is divided again after passing through a fourth valve 47, one part of the refrigerant enters a second compressor 45 after passing through a freezing showcase throttling device 441, a fourth flow divider 431, a freezing showcase heat exchanger 411 (as an evaporator) and a second reversing device 461 in sequence, one part of the refrigerant passes through a freezing showcase throttling device 442, a fourth flow divider 432 and a freezing showcase heat exchanger 412 (as an evaporator) in sequence, the second reversing device 462 enters the second compressor 45, and the other refrigerant enters the second compressor 45 after passing through the refrigeration showcase throttling device 443, the fourth diverter 433, the refrigeration showcase heat exchanger 413 (serving as an evaporator) and the second reversing device 463 in sequence, at this time, the refrigeration showcase fan 42 is started, the refrigeration

showcase throttling devices

441, 442 and 443 are all opened, and the second compressor 45 works. Thereafter, the two streams of refrigerant that have exited the refrigerated display case 3 and the refrigerated display case 4 join together again, and enter the first compressor 111. In the entire process, third compressor 112 is not operating, third four-way valve 123 is powered on (i.e., the suction ports of the two first compressors are in communication), and third valve 17 is closed.

The heat exchangers of the refrigeration showcase are alternately defrosted, and the defrosting sequence and the number of the heat exchangers for defrosting at each time can be set according to actual requirements. The defrost mode is divided into three stages in this example: defrost mode 1 (freeze showcase heat exchanger 413 defrosting), defrost mode 2 (freeze showcase heat exchanger 412 defrosting), and defrost mode 3 (freeze showcase heat exchanger 411 defrosting).

As shown in fig. 6B, in the defrost mode 1, the refrigerant discharged from the first compressor 111 is branched. A part of refrigerant enters the air conditioner indoor unit 2 through the first four-way valve 121 (the first four-way valve 121 is in a power-down state, that is, the port connected with the heat exchanger 21 of the air conditioner indoor unit is communicated with the port connected with the exhaust port of the first compressor 111, and the port connected with the second four-way valve 122 is communicated with the port connected with the first reversing device 16), and in the air conditioner indoor unit 2, the refrigerant sequentially passes through the heat exchanger 21 (serving as a condenser) of the air conditioner indoor unit, the second flow divider 23 and the throttling device 24 of the air conditioner indoor unit, at this time, the fan 22 of the air conditioner indoor unit. The refrigerant then enters the refrigerated display case 3, passes through the refrigerated display case throttling device 34, the third flow diverter 33, and the refrigerated display case heat exchanger 31 (acting as an evaporator) in that order within the refrigerated display case 3, whereupon the refrigerated display case fan 32 is activated and the refrigerated display case throttling device 34 is opened. The other part of the refrigerant enters the refrigerated display case 4 through the first reversing device 16 (the first reversing device 16 is in a power-off state, that is, the first four-way valve 121 is communicated with the bypass pipeline, and the first four-way valve 121 is not communicated with the outdoor heat exchanger 13), in the refrigerated display case 4, the refrigerant firstly passes through the second reversing device 463, enters the refrigerated display case heat exchanger 413 (acting as a condenser), the fourth diverter 433 and the refrigerated display case throttling device 443, then the refrigerant is branched, one part of the refrigerant enters the second compressor 45 after sequentially passing through the refrigerated display case throttling device 442, the fourth diverter 432, the refrigerated display case heat exchanger 412 (acting as an evaporator) and the second reversing device 462, the other part of the refrigerant enters the second compressor 45 after sequentially passing through the refrigerated display case throttling device 441, the fourth diverter 431, the refrigerated display case heat exchanger 411 (acting as an evaporator) and the second reversing device 461, the fourth valve 47 is now closed. Thereafter, the two streams of refrigerant that come out of the refrigerated showcase 3 and the refrigerated showcase 4 join together, and the refrigerant enters the first compressor 111. In the whole process, the third compressor 112 does not operate, the third four-way valve 123 is powered on (i.e., the suction ports of the two first compressors are communicated), the third valve 17 is opened, the third stop valve 183 is closed, and the outdoor fan 14 stops operating after meeting the conditions (i.e., when the outlet temperature of the outdoor heat exchanger 13 is not changed for a period of time).

As shown in fig. 6C, in the defrost mode 2, the refrigerant discharged from the first compressor 111 is branched. A part of refrigerant enters the air conditioner indoor unit 2 through the first four-way valve 121 (the first four-way valve 121 is in a power-down state, that is, the port connected with the heat exchanger 21 of the air conditioner indoor unit is communicated with the port connected with the exhaust port of the first compressor 111, and the port connected with the second four-way valve 122 is communicated with the port connected with the first reversing device 16), and in the air conditioner indoor unit 2, the refrigerant sequentially passes through the heat exchanger 21 (serving as a condenser) of the air conditioner indoor unit, the second flow divider 23 and the throttling device 24 of the air conditioner indoor unit, at this time, the fan 22 of the air conditioner indoor unit. The refrigerant then enters the refrigerated display case 3, passes through the refrigerated display case throttling device 34, the third flow diverter 33, and the refrigerated display case heat exchanger 31 (acting as an evaporator) in that order within the refrigerated display case 3, whereupon the refrigerated display case fan 32 is activated and the refrigerated display case throttling device 34 is opened. The other part of the refrigerant enters the refrigerated display case 4 through the first reversing device 16 (the first reversing device 16 is in a power-off state, that is, the first four-way valve 121 is communicated with the bypass pipeline, and the first four-way valve 121 is not communicated with the outdoor heat exchanger 13), in the refrigerated display case 4, the refrigerant firstly passes through the second reversing device 462, enters the refrigerated display case heat exchanger 412 (acting as a condenser), the fourth diverter 432 and the refrigerated display case throttling device 442, then the refrigerant is divided, one part of the refrigerant sequentially passes through the refrigerated display case throttling device 441, the fourth diverter 431, the refrigerated display case heat exchanger 411 (acting as an evaporator) and the second reversing device 461 and enters the second compressor 45, the other part of the refrigerant sequentially passes through the refrigerated display case throttling device 443, the fourth diverter 433, the refrigerated display case heat exchanger 413 (acting as an evaporator) and the second reversing device 463 and enters the second compressor 45, the fourth valve 47 is now closed. Thereafter, the two streams of refrigerant that come out of the refrigerated showcase 3 and the refrigerated showcase 4 join together, and the refrigerant enters the first compressor 111. In the whole process, the third compressor 112 does not operate, the third four-way valve 123 is powered on (i.e., the suction ports of the two first compressors are communicated), the third valve 17 is opened, the third stop valve 183 is closed, and the outdoor fan 14 stops operating after meeting the conditions (i.e., when the outlet temperature of the outdoor heat exchanger 13 is not changed for a period of time).

As shown in fig. 6D, in the defrost mode 3, the refrigerant discharged from the first compressor 111 is branched. A part of refrigerant enters the air conditioner indoor unit 2 through the first four-way valve 121 (the first four-way valve 121 is in a power-down state, that is, the port connected with the heat exchanger 21 of the air conditioner indoor unit is communicated with the port connected with the exhaust port of the first compressor 111, and the port connected with the second four-way valve 122 is communicated with the port connected with the first reversing device 16), and in the air conditioner indoor unit 2, the refrigerant sequentially passes through the heat exchanger 21 (serving as a condenser) of the air conditioner indoor unit, the second flow divider 23 and the throttling device 24 of the air conditioner indoor unit, at this time, the fan 22 of the air conditioner indoor unit. The refrigerant then enters the refrigerated display case 3, passes through the refrigerated display case throttling device 34, the third flow diverter 33, and the refrigerated display case heat exchanger 31 (acting as an evaporator) in that order within the refrigerated display case 3, whereupon the refrigerated display case fan 32 is activated and the refrigerated display case throttling device 34 is opened. The other part of the refrigerant enters the refrigerated display case 4 through the first reversing device 16 (the first reversing device 16 is in a power-off state, that is, the first four-way valve 121 is communicated with the bypass pipeline, and the first four-way valve 121 is not communicated with the outdoor heat exchanger 13), in the refrigerated display case 4, the refrigerant firstly passes through the second reversing device 461, enters the refrigerated display case heat exchanger 411 (acting as a condenser), the fourth diverter 431 and the refrigerated display case throttling device 441, then the refrigerant is branched, one part of the refrigerant sequentially passes through the refrigerated display case throttling device 442, the fourth diverter 432, the refrigerated display case heat exchanger 412 (acting as an evaporator) and the second reversing device 462 and then enters the second compressor 45, the other part of the refrigerant sequentially passes through the refrigerated display case throttling device 443, the fourth diverter 433, the refrigerated display case heat exchanger 413 (acting as an evaporator) and the second reversing device 463 and then enters the second compressor, the fourth valve 47 is now closed. Thereafter, the two streams of refrigerant that come out of the refrigerated showcase 3 and the refrigerated showcase 4 join together, and the refrigerant enters the first compressor 111. In the whole process, the third compressor 112 does not operate, the third four-way valve 123 is powered on (i.e., the suction ports of the two first compressors are communicated), the third valve 17 is opened, the third stop valve 183 is closed, and the outdoor fan 14 stops operating after meeting the conditions (i.e., when the outlet temperature of the outdoor heat exchanger 13 is not changed for a period of time).

As shown in fig. 7, the defrosting control flow corresponding to fig. 6A to 6D includes the following steps:

and S701, when the defrosting flag bit of the system is effective, the system enters a defrosting mode.

S702, the first compressor 111 is adjusted to the preset reversing frequency Fset of the first reversing device 16.

And S703, adjusting the first reversing device 16 from the power-on state to the power-off state, and changing the flowing direction of the refrigerant. Specifically, the first four-way valve 121 is communicated with the bypass line, and the first four-way valve 121 is not communicated with the outdoor heat exchanger 13. Then, the control of S704-S706 is performed simultaneously.

And S704, controlling the outdoor fan 14 to stop working when the outlet temperature T1 of the outdoor heat exchanger 13 is unchanged for x seconds.

S705, the operation frequency of the first compressor 111 is adjusted according to the exhaust pressure P1(P1 is less than or equal to Pset).

S706, the second switching device 463 is switched to a state in which the refrigerated showcase heat exchanger 413 and the bypass line are communicated with each other, the refrigerated showcase throttling device 443 is adjusted to the maximum opening degree, and the fourth valve 47 is closed. Other controllable components are controlled according to the original control logic.

S707, after y seconds, the second switching device 463 switches to a state in which the refrigerated showcase heat exchanger 413 and the second compressor 45 are communicated, and the refrigerated showcase throttling device 443 resumes the original control; the second reversing device 462 is switched to a state in which the refrigeration showcase heat exchanger 412 and the bypass line are communicated, and the refrigeration showcase throttling device 442 is adjusted to the maximum opening degree.

S708, after y seconds, the second reversing device 462 switches to a state of communicating the refrigerated display case heat exchanger 412 and the second compressor 45, and the refrigerated display case throttling device 442 resumes its original control; the second direction changer 461 is switched to a state where the refrigerating showcase heat exchanger 411 and the bypass line are communicated with each other, and the refrigerating showcase throttling device 441 is adjusted to the maximum opening degree.

(2) Aiming at the situation of the connection mode 2 of the heat exchanger of the refrigeration showcase

In this embodiment, the second reversing device shared by the two refrigerated display case heat exchangers (e.g., 411 and 412) includes three states: state 1, corresponding to a heating mode or to a case where neither of the two refrigerated

showcase heat exchangers

411 and 412 is defrosted in the defrosting mode, communicating the refrigerated showcase heat exchanger 411 with the second compressor 45 and communicating the refrigerated showcase heat exchanger 412 with the second compressor 45; state 2, corresponding to the refrigeration showcase heat exchanger 412 defrosting, communicating the refrigeration showcase heat exchanger 412 with the bypass line and communicating the refrigeration showcase heat exchanger 411 with the second compressor 45; in state 3, corresponding to the refrigeration cabinet heat exchanger 411 defrosting, the refrigeration cabinet heat exchanger 411 is communicated with the bypass line and the refrigeration cabinet heat exchanger 412 is communicated with the second compressor 45.

Fig. 8A to 8C illustrate the refrigerant flow directions in the heating mode and the defrosting mode, taking the refrigeration showcase including two heat exchangers (411 and 412) as an example.

As shown in fig. 8A, in the heating mode, the refrigerant discharged from the first compressor 111 is branched. A part of refrigerant enters the air conditioner indoor unit 2 through the first four-way valve 121 (the first four-way valve 121 is in a power-down state, that is, the port connected with the heat exchanger 21 of the air conditioner indoor unit is communicated with the port connected with the exhaust port of the first compressor 111, and the port connected with the second four-way valve 122 is communicated with the port connected with the first reversing device 16), and in the air conditioner indoor unit 2, the refrigerant sequentially passes through the heat exchanger 21 (serving as a condenser) of the air conditioner indoor unit, the second flow divider 23 and the throttling device 24 of the air conditioner indoor unit, at this time, the fan 22 of the air conditioner indoor unit. The other part of the refrigerant enters the outdoor heat exchanger 13 (acting as a condenser) through the first reversing device 16 (the first reversing device 16 is in a power-on state, that is, the first four-way valve 121 is communicated with the outdoor heat exchanger 13, and the first four-way valve 121 is not communicated with the bypass pipeline), and passes through the first flow divider 15. Then, the two refrigerants are merged and split again. A portion of the refrigerant enters the refrigerated display case 3, and in the refrigerated display case 3, the refrigerant passes through a refrigerated display case throttling device 34, a third flow divider 33, and a refrigerated display case heat exchanger 31 (acting as an evaporator) in this order, at which time a refrigerated display case fan 32 is activated and the refrigerated display case throttling device 34 is opened. The other part of the refrigerant enters the refrigeration showcase 4, in the refrigeration showcase 4, the refrigerant is divided again after passing through the fourth valve 47, one part of the refrigerant passes through the refrigeration showcase throttling device 441, the fourth flow divider 431 and the refrigeration showcase heat exchanger 411 (as an evaporator) in sequence, the other part of the refrigerant passes through the refrigeration showcase throttling device 442, the fourth flow divider 432 and the refrigeration showcase heat exchanger 412 (as an evaporator) in sequence, then two parts of the refrigerant are converged and enter the second compressor 45 through the second common reversing device 461 (in the state 1), at this time, the refrigeration showcase fan 42 is started, the refrigeration

showcase throttling devices

441 and 442 are both opened, and the second compressor 45 works. Thereafter, the two streams of refrigerant that have exited the refrigerated display case 3 and the refrigerated display case 4 join together again, and enter the first compressor 111. In the entire process, third compressor 112 is not operating, third four-way valve 123 is powered on (i.e., the suction ports of the two first compressors are in communication), and third valve 17 is closed.

The heat exchangers of the refrigeration showcase are alternately defrosted, and the defrosting sequence and the number of the heat exchangers for defrosting at each time can be set according to actual requirements. The defrost mode is divided into two stages in this example: defrost mode 1 (freeze showcase heat exchanger 412 defrosting) and defrost mode 2 (freeze showcase heat exchanger 411 defrosting).

As shown in fig. 8B, in the defrosting mode 1, the refrigerant discharged from the first compressor 111 is branched. A part of refrigerant enters the air conditioner indoor unit 2 through the first four-way valve 121 (the first four-way valve 121 is in a power-down state, that is, the port connected with the heat exchanger 21 of the air conditioner indoor unit is communicated with the port connected with the exhaust port of the first compressor 111, and the port connected with the second four-way valve 122 is communicated with the port connected with the first reversing device 16), and in the air conditioner indoor unit 2, the refrigerant sequentially passes through the heat exchanger 21 (serving as a condenser) of the air conditioner indoor unit, the second flow divider 23 and the throttling device 24 of the air conditioner indoor unit, at this time, the fan 22 of the air conditioner indoor unit. The refrigerant then enters the refrigerated display case 3, passes through the refrigerated display case throttling device 34, the third flow diverter 33, and the refrigerated display case heat exchanger 31 (acting as an evaporator) in that order within the refrigerated display case 3, whereupon the refrigerated display case fan 32 is activated and the refrigerated display case throttling device 34 is opened. Another part of the refrigerant enters the refrigerated display case 4 through the first reversing device 16 (the first reversing device 16 is in a power-off state, that is, the first four-way valve 121 is communicated with the bypass pipeline, and the first four-way valve 121 is not communicated with the outdoor heat exchanger 13), in the refrigerated display case 4, the refrigerant first passes through the shared second reversing device 461 (in a state 2), enters the refrigerated display case heat exchanger 412 (serving as a condenser), the fourth diverter 432 and the refrigerated display case throttling device 442, then passes through the refrigerated display case throttling device 441 and the fourth diverter 431, enters the refrigerated display case heat exchanger 411 (serving as an evaporator), and then enters the second compressor 45 through the shared second reversing device 461, and at this time, the fourth valve 47 is closed. Thereafter, the two streams of refrigerant that come out of the refrigerated showcase 3 and the refrigerated showcase 4 join together, and the refrigerant enters the first compressor 111. In the whole process, the third compressor 112 does not operate, the third four-way valve 123 is powered on (i.e., the suction ports of the two first compressors are communicated), the third valve 17 is opened, the third stop valve 183 is closed, and the outdoor fan 14 stops operating after meeting the conditions (i.e., when the outlet temperature of the outdoor heat exchanger 13 is not changed for a period of time).

As shown in fig. 8C, in the defrost mode 2, the refrigerant discharged from the first compressor 111 is branched. A part of refrigerant enters the air conditioner indoor unit 2 through the first four-way valve 121 (the first four-way valve 121 is in a power-down state, that is, the port connected with the heat exchanger 21 of the air conditioner indoor unit is communicated with the port connected with the exhaust port of the first compressor 111, and the port connected with the second four-way valve 122 is communicated with the port connected with the first reversing device 16), and in the air conditioner indoor unit 2, the refrigerant sequentially passes through the heat exchanger 21 (serving as a condenser) of the air conditioner indoor unit, the second flow divider 23 and the throttling device 24 of the air conditioner indoor unit, at this time, the fan 22 of the air conditioner indoor unit. The refrigerant then enters the refrigerated display case 3, passes through the refrigerated display case throttling device 34, the third flow diverter 33, and the refrigerated display case heat exchanger 31 (acting as an evaporator) in that order within the refrigerated display case 3, whereupon the refrigerated display case fan 32 is activated and the refrigerated display case throttling device 34 is opened. Another part of the refrigerant enters the refrigerated display case 4 through the first reversing device 16 (the first reversing device 16 is in a power-off state, that is, the first four-way valve 121 is communicated with the bypass pipeline, and the first four-way valve 121 is not communicated with the outdoor heat exchanger 13), in the refrigerated display case 4, the refrigerant first passes through the shared second reversing device 461 (in a state 3), enters the refrigerated display case heat exchanger 411 (serving as a condenser), the fourth diverter 431 and the refrigerated display case throttling device 441, then passes through the refrigerated display case throttling device 442 and the fourth diverter 432, enters the refrigerated display case heat exchanger 412 (serving as an evaporator), and then enters the second compressor 45 through the shared second reversing device 461, and at this time, the fourth valve 47 is closed. Thereafter, the two streams of refrigerant that come out of the refrigerated showcase 3 and the refrigerated showcase 4 join together, and the refrigerant enters the first compressor 111. In the whole process, the third compressor 112 does not operate, the third four-way valve 123 is powered on (i.e., the suction ports of the two first compressors are communicated), the third valve 17 is opened, the third stop valve 183 is closed, and the outdoor fan 14 stops operating after meeting the conditions (i.e., when the outlet temperature of the outdoor heat exchanger 13 is not changed for a period of time).

As shown in fig. 9, a defrosting control flow corresponding to fig. 8A to 8C includes the steps of:

and S901, when the defrosting flag bit of the system is effective, the system enters a defrosting mode.

S902, the first compressor 111 is adjusted to the preset reversing frequency Fset of the first reversing device 16.

And S903, the first reversing device 16 is adjusted from a power-on state to a power-off state, and the flowing direction of the refrigerant is changed. Specifically, the first four-way valve 121 is communicated with the bypass line, and the first four-way valve 121 is not communicated with the outdoor heat exchanger 13. Then, the control of S904-S906 is performed simultaneously.

And S904, controlling the outdoor fan 14 to stop working when the outlet temperature T1 of the outdoor heat exchanger 13 is unchanged for x seconds.

S905, adjusting the operating frequency of the first compressor 111 according to the exhaust pressure P1(P1 is less than or equal to Pset).

In S906, the second direction changer 461 is switched from state 1 (heating mode) to state 2 (defrosting mode 1), the freezer showcase throttling device 442 is adjusted to the maximum opening degree, and the fourth valve 47 is closed.

In S907, after y seconds, the second direction changer 461 is switched from state 2 (defrost mode 1) to state 3 (defrost mode 2), the freezer showcase throttling device 441 is adjusted to the maximum opening, and the freezer showcase throttling device 442 returns to the original control.

Fig. 10A to 10D show the refrigerant flow direction in the heating mode and the defrosting mode by taking the freezing showcase including three heat exchangers (411, 412, and 413) as an example, wherein the freezing

showcase heat exchangers

411 and 412 share the second reversing device 461, and the freezing showcase heat exchanger 413 corresponds to one second reversing device 462 individually. The defrost mode is divided into three stages in this example: defrost mode 1 (freeze showcase heat exchanger 413 defrosting), defrost mode 2 (freeze showcase heat exchanger 412 defrosting), and defrost mode 3 (freeze showcase heat exchanger 411 defrosting).

As shown in fig. 10A, in the heating mode, the refrigerant flow direction differs from that in fig. 8A in that: after the refrigerant is branched by the fourth valve 47, another refrigerant passes through the refrigeration showcase throttling device 443, the fourth flow divider 433, the refrigeration showcase heat exchanger 413 (as an evaporator) and the second reversing device 462 in sequence, and then enters the second compressor 45.

As shown in fig. 10B, in the defrosting mode 1, the refrigerated display case heat exchanger 413 performs defrosting, which is a new round of defrosting compared to fig. 8A to 8C, specifically, the refrigerant entering the refrigerated display case 4 through the bypass line sequentially passes through the second reversing device 462, the refrigerated display case heat exchanger 413 (serving as a condenser), the fourth flow divider 433, and the refrigerated display case throttling device 443, then the refrigerant is divided, a part of the refrigerant sequentially passes through the refrigerated display case throttling device 441 and the fourth flow divider 431 to enter the refrigerated display case heat exchanger 411 (serving as an evaporator), another part of the refrigerant sequentially passes through the refrigerated display case throttling device 442 and the fourth flow divider 432 to enter the refrigerated display case heat exchanger 412 (serving as an evaporator), and then two streams of the refrigerant are merged by the common second reversing device 461 to enter the second compressor 45.

As shown in fig. 10C, in the defrosting mode 2, the refrigerant flow direction differs from that in fig. 8B in that: the refrigerant flowing out of the freezer showcase throttling means 442 is branched, and a part of the refrigerant flows to the freezer showcase throttling means 441 as in fig. 8B, and the other part of the refrigerant passes through the freezer showcase throttling means 443 and the fourth branching means 433 in this order, enters the freezer showcase heat exchanger 413 (serving as an evaporator), and then enters the second compressor 45 through the second reversing means 462.

As shown in fig. 10D, in the defrosting mode 3, the refrigerant flow direction is different from that in fig. 8C in that: the refrigerant flowing out of the freezer showcase throttling means 441 is branched, and a part of the refrigerant flows to the freezer showcase throttling means 442 as in fig. 8C, and the other part of the refrigerant passes through the freezer showcase throttling means 443 and the fourth branching means 433 in this order, enters the freezer showcase heat exchanger 413 (serving as an evaporator), and then enters the second compressor 45 through the second reversing means 462.

As shown in fig. 11, a defrosting control flow corresponding to fig. 10A to 10D includes the steps of:

and S1101, when the defrosting flag bit of the system is effective, the system enters a defrosting mode.

S1102, the first compressor 111 is adjusted to the preset reversing frequency Fset of the first reversing device 16.

S1103, the first direction changing device 16 is adjusted from the power-on state to the power-off state, and the flowing direction of the refrigerant is changed. Specifically, the first four-way valve 121 is communicated with the bypass line, and the first four-way valve 121 is not communicated with the outdoor heat exchanger 13. Then, the control of S1104 to S1106 is performed simultaneously.

And S1104, when the outlet temperature T1 of the outdoor heat exchanger 13 is unchanged for x seconds, controlling the outdoor fan 14 to stop working.

S1105, adjusting the operation frequency of the first compressor 111 according to the exhaust pressure P1(P1 is less than or equal to Pset).

In S1106, the second reversing device 462 is switched to a state in which the refrigeration showcase heat exchanger 413 and the bypass line are communicated, the refrigeration showcase throttling device 443 is adjusted to the maximum opening degree, and the fourth valve 47 is closed.

S1107, after y seconds, the second reversing device 462 switches to the state of communicating the refrigerated showcase heat exchanger 413 and the second compressor 45, and the refrigerated showcase throttling device 443 resumes the original control; the common second direction changer 461 is switched from state 1 (heating mode and defrosting mode 1) to state 2 (defrosting mode 2), and the freezer showcase throttling device 442 is adjusted to the maximum opening degree.

In S1108, after y seconds, the common second direction changer 461 is switched from state 2 (defrost mode 2) to state 3 (defrost mode 3), the freezer showcase damper 441 is adjusted to the maximum opening, and the freezer showcase damper 442 returns to its original control.

(3) Aiming at the condition of the connection mode 3 of the heat exchanger of the refrigeration showcase

Fig. 12A to 12C illustrate the refrigerant flow directions in the heating mode and the defrosting mode, taking a refrigeration showcase including two heat exchangers (411 and 412) as an example.

As shown in fig. 12A, in the heating mode, the refrigerant discharged from the first compressor 111 is branched. A part of refrigerant enters the air conditioner indoor unit 2 through the first four-way valve 121 (the first four-way valve 121 is in a power-down state, that is, the port connected with the heat exchanger 21 of the air conditioner indoor unit is communicated with the port connected with the exhaust port of the first compressor 111, and the port connected with the second four-way valve 122 is communicated with the port connected with the first reversing device 16), and in the air conditioner indoor unit 2, the refrigerant sequentially passes through the heat exchanger 21 (serving as a condenser) of the air conditioner indoor unit, the second flow divider 23 and the throttling device 24 of the air conditioner indoor unit, at this time, the fan 22 of the air conditioner indoor unit. The other part of the refrigerant enters the outdoor heat exchanger 13 (acting as a condenser) through the first reversing device 16 (the first reversing device 16 is in a power-on state, that is, the first four-way valve 121 is communicated with the outdoor heat exchanger 13, and the first four-way valve 121 is not communicated with the bypass pipeline), and passes through the first flow divider 15. Then, the two refrigerants are merged and split again. A portion of the refrigerant enters the refrigerated display case 3, and in the refrigerated display case 3, the refrigerant passes through a refrigerated display case throttling device 34, a third flow divider 33, and a refrigerated display case heat exchanger 31 (acting as an evaporator) in this order, at which time a refrigerated display case fan 32 is activated and the refrigerated display case throttling device 34 is opened. The other part of the refrigerant enters the freezing showcase 4, in the freezing showcase 4, the refrigerant is divided again after passing through a fourth valve 47, one part of the refrigerant passes through a freezing showcase throttling device 441, a fourth flow divider 431, a freezing showcase heat exchanger 411 (as an evaporator) and a fifth valve 481 in sequence, the other part of the refrigerant passes through a freezing showcase throttling device 442, a fourth flow divider 432, a freezing showcase heat exchanger 412 (as an evaporator) and a fifth valve 482 in sequence, then, the two refrigerants join together and enter the second compressor 45, at this time, the sixth valve 491 corresponding to the refrigerated showcase heat exchanger 411 and the sixth valve 492 corresponding to the refrigerated showcase heat exchanger 412 are both closed, the refrigerated showcase fan 42 is started, the refrigerated showcase throttling device 441 corresponding to the refrigerated showcase heat exchanger 411 and the refrigerated showcase throttling device 442 corresponding to the refrigerated showcase heat exchanger 412 are both opened, and the second compressor 45 is operated. Thereafter, the two streams of refrigerant that have exited the refrigerated display case 3 and the refrigerated display case 4 join together again, and enter the first compressor 111. In the entire process, third compressor 112 is not operating, third four-way valve 123 is powered on (i.e., the suction ports of the two first compressors are in communication), and third valve 17 is closed.

As shown in fig. 12B, in the defrosting mode 1, the refrigerant discharged from the first compressor 111 is branched. A part of refrigerant enters the air conditioner indoor unit 2 through the first four-way valve 121 (the first four-way valve 121 is in a power-down state, that is, the port connected with the heat exchanger 21 of the air conditioner indoor unit is communicated with the port connected with the exhaust port of the first compressor 111, and the port connected with the second four-way valve 122 is communicated with the port connected with the first reversing device 16), and in the air conditioner indoor unit 2, the refrigerant sequentially passes through the heat exchanger 21 (serving as a condenser) of the air conditioner indoor unit, the second flow divider 23 and the throttling device 24 of the air conditioner indoor unit, at this time, the fan 22 of the air conditioner indoor unit. The refrigerant then enters the refrigerated display case 3, passes through the refrigerated display case throttling device 34, the third flow diverter 33, and the refrigerated display case heat exchanger 31 (acting as an evaporator) in that order within the refrigerated display case 3, whereupon the refrigerated display case fan 32 is activated and the refrigerated display case throttling device 34 is opened. Another part of the refrigerant enters the refrigerated display case 4 through the first reversing device 16 (the first reversing device 16 is in a power-off state, that is, the first four-way valve 121 is communicated with the bypass pipeline, and the first four-way valve 121 is not communicated with the outdoor heat exchanger 13), in the refrigerated display case 4, the refrigerant firstly enters the refrigerated display case heat exchanger 412 (serving as a condenser), the fourth diverter 432 and the refrigerated display case throttling device 442 through the sixth valve 492, then the refrigerant passes through the refrigerated display case throttling device 441, the fourth diverter 431, the refrigerated display case heat exchanger 411 (serving as an evaporator) and the fifth valve 481, and the refrigerant coming out subsequently enters the second compressor 45, at this time, the fourth valve 47, the fifth valve 482 corresponding to the refrigerated display case heat exchanger 412 and the sixth valve 491 corresponding to the refrigerated display case heat exchanger 411 are closed. Thereafter, the two streams of refrigerant that come out of the refrigerated showcase 3 and the refrigerated showcase 4 join together, and the refrigerant enters the first compressor 111. In the whole process, the third compressor 112 does not operate, the third four-way valve 123 is powered on (i.e., the suction ports of the two first compressors are communicated), the third valve 17 is opened, the third stop valve 183 is closed, and the outdoor fan 14 stops operating after meeting the conditions (i.e., when the outlet temperature of the outdoor heat exchanger 13 is not changed for a period of time).

As shown in fig. 12C, in the defrosting mode 2, the refrigerant discharged from the first compressor 111 is branched. A part of refrigerant enters the air conditioner indoor unit 2 through the first four-way valve 121 (the first four-way valve 121 is in a power-down state, that is, the port connected with the heat exchanger 21 of the air conditioner indoor unit is communicated with the port connected with the exhaust port of the first compressor 111, and the port connected with the second four-way valve 122 is communicated with the port connected with the first reversing device 16), and in the air conditioner indoor unit 2, the refrigerant sequentially passes through the heat exchanger 21 (serving as a condenser) of the air conditioner indoor unit, the second flow divider 23 and the throttling device 24 of the air conditioner indoor unit, at this time, the fan 22 of the air conditioner indoor unit. The refrigerant then enters the refrigerated display case 3, passes through the refrigerated display case throttling device 34, the third flow diverter 33, and the refrigerated display case heat exchanger 31 (acting as an evaporator) in that order within the refrigerated display case 3, whereupon the refrigerated display case fan 32 is activated and the refrigerated display case throttling device 34 is opened. The other part of the refrigerant enters the refrigerated display case 4 through the first reversing device 16 (the first reversing device 16 is in a power-off state, that is, the first four-way valve 121 is communicated with the bypass pipeline, and the first four-way valve 121 is not communicated with the outdoor heat exchanger 13), in the refrigerated display case 4, the refrigerant firstly passes through a sixth valve 491, enters a refrigerated display case heat exchanger 411 (serving as a condenser), a fourth diverter 431 and a refrigerated display case throttling device 441, then the refrigerant sequentially passes through the refrigerated display case throttling device 442, the fourth diverter 432, the refrigerated display case heat exchanger 412 (serving as an evaporator) and a fifth valve 482, and the refrigerant coming out enters the second compressor 45, at this time, the sixth valve 492 and the fourth valve 47 corresponding to the refrigerated display case heat exchanger 412 and the fifth valve 481 corresponding to the refrigerated display case heat exchanger 411 are closed. Thereafter, the two streams of refrigerant that come out of the refrigerated showcase 3 and the refrigerated showcase 4 join together, and the refrigerant enters the first compressor 111. In the whole process, the third compressor 112 does not operate, the third four-way valve 123 is powered on (i.e., the suction ports of the two first compressors are communicated), the third valve 17 is opened, the third stop valve 183 is closed, and the outdoor fan 14 stops operating after meeting the conditions (i.e., when the outlet temperature of the outdoor heat exchanger 13 is not changed for a period of time).

As shown in fig. 13, a defrosting control flow corresponding to fig. 12A to 12C includes the steps of:

and S1301, when the defrosting flag bit of the system is effective, the system enters a defrosting mode.

S1302, the first compressor 111 is adjusted to the preset reversing frequency Fset of the first reversing device 16.

And S1303, the first reversing device 16 is adjusted from the power-on state to the power-off state, and the flowing direction of the refrigerant is changed. Specifically, the first four-way valve 121 is communicated with the bypass line, and the first four-way valve 121 is not communicated with the outdoor heat exchanger 13. Then, the control of S1304 to S1306 is executed simultaneously.

And S1304, controlling the outdoor fan 14 to stop working when the outlet temperature T1 of the outdoor heat exchanger 13 is unchanged for x seconds.

S1305, the operation frequency of the first compressor 111 is adjusted according to the exhaust pressure P1(P1 is less than or equal to Pset).

In S1306, the sixth valve 492 is opened, the fifth valve 482 is closed, the unit is switched from the heating mode to the defrosting mode 1, the freezer showcase throttling device 442 is adjusted to the maximum opening, and the fourth valve 47 is closed.

In S1307, after y seconds, the fifth valve 482 and the sixth valve 491 are opened, the sixth valve 492 and the fifth valve 481 are closed, the unit is switched from the defrosting mode 1 to the defrosting mode 2, the refrigeration showcase throttling device 441 is adjusted to the maximum opening degree, and the refrigeration showcase throttling device 442 returns to the original control.

Fig. 14A to 14D illustrate the refrigerant flow directions in the heating mode and the defrosting mode, taking a refrigeration showcase including three heat exchangers (411, 412, and 413) as an example. The defrost mode is divided into three stages in this example: defrost mode 1 (freeze showcase heat exchanger 413 defrosting), defrost mode 2 (freeze showcase heat exchanger 412 defrosting), and defrost mode 3 (freeze showcase heat exchanger 411 defrosting).

As shown in fig. 14A, in the heating mode, the refrigerant flow direction differs from that in fig. 12A in that: after the refrigerant is branched by the fourth valve 47, another refrigerant passes through the refrigeration showcase throttling device 443, the fourth flow divider 433, the refrigeration showcase heat exchanger 413 (as an evaporator), the fifth valve 483 in sequence, and enters the second compressor 45.

As shown in fig. 14B, in the defrosting mode 1, the refrigerated display case heat exchanger 413 performs defrosting, which is a new round of defrosting compared to fig. 12A to 12C, specifically, the refrigerant entering the refrigerated display case 4 through the bypass line sequentially passes through the sixth valve 493, the refrigerated display case heat exchanger 413 (serving as a condenser), the fourth flow divider 433, and the refrigerated display case throttling device 443, and then the refrigerant is divided, and a part of the refrigerant passes through the refrigerated display case throttling device 441 and the fourth flow divider 431 to enter the refrigerated display case heat exchanger 411 (serving as an evaporator), and then enters the second compressor 45 through the fifth valve 481, and another part of the refrigerant passes through the refrigerated display case throttling device 442 and the fourth flow divider 432 to enter the refrigerated display case heat exchanger 412 (serving as an evaporator), and then enters the second compressor 45 through the fifth valve 482.

As shown in fig. 14C, in the defrosting mode 2, the refrigerant flow direction differs from that in fig. 12B in that: the refrigerant flowing out of the freezer showcase throttling means 442 is branched, and a part of the refrigerant flows to the freezer showcase throttling means 441 as in fig. 12B, and the other part of the refrigerant passes through the freezer showcase throttling means 443 and the fourth branching means 433 in this order, enters the freezer showcase heat exchanger 413 (serving as an evaporator), and then enters the second compressor 45 through the fifth valve 483.

As shown in fig. 14D, in the defrosting mode 3, the refrigerant flow direction differs from that in fig. 12C in that: the refrigerant flowing out of the freezer showcase throttling means 441 is branched, and a part of the refrigerant flows to the freezer showcase throttling means 442 as in fig. 12C, and the other part of the refrigerant passes through the freezer showcase throttling means 443 and the fourth branching means 433 in this order, enters the freezer showcase heat exchanger 413 (serving as an evaporator), and then enters the second compressor 45 through the fifth valve 483.

As shown in fig. 15, a defrosting control flow corresponding to fig. 14A to 14D includes the steps of:

and S1501, when the defrosting flag bit of the system is effective, the system enters a defrosting mode.

S1502, the first compressor 111 is adjusted to the preset commutation frequency Fset of the first commutation device 16.

S1503, the first direction changing device 16 is adjusted from the power-on state to the power-off state, and the flowing direction of the refrigerant is changed. Specifically, the first four-way valve 121 is communicated with the bypass line, and the first four-way valve 121 is not communicated with the outdoor heat exchanger 13. Then, the control of S1504 to S1506 is performed simultaneously.

And S1504, controlling the outdoor fan 14 to stop working when the outlet temperature T1 of the outdoor heat exchanger 13 is unchanged for x seconds.

S1505, adjusting the operation frequency of the first compressor 111 according to the exhaust pressure P1(P1 ≦ Pset).

S1506, the sixth valve 493 is opened, the fifth valve 483 is closed, the unit is switched from the heating mode to the defrosting mode 1, the throttle 443 of the refrigerated showcase is adjusted to the maximum opening, and the fourth valve 47 is closed.

S1507, after y seconds, the sixth valve 492 and the fifth valve 483 are opened, the sixth valve 493 and the fifth valve 482 are closed, the unit is switched from the defrosting mode 1 to the defrosting mode 2, the freezing showcase throttle device 442 is adjusted to the maximum opening, and the freezing showcase throttle device 443 returns to the original control.

In S1508, after y seconds, the sixth valve 491, the fifth valve 482, the sixth valve 492, and the fifth valve 481 are opened, the unit is switched from the defrosting mode 2 to the defrosting mode 3, the freezing showcase throttling device 441 is adjusted to the maximum opening, and the freezing showcase throttling device 442 returns to the original control.

If the bypass line structure shown in fig. 2 is adopted, the control related to the first reversing device 16 in the flow shown in fig. 7, 9, 11, 13, and 15 may be replaced by: the second valve 192 is opened, the first valve 191 is closed, and the flow direction of the refrigerant is changed.

According to the refrigeration and cold storage device and the control method thereof, the bypass pipeline is arranged, so that high-temperature and high-pressure gas discharged by the first compressor can directly enter the refrigeration showcase, and the quick defrosting of the refrigeration showcase is realized; at least two heat exchangers connected with each other are arranged in the refrigeration display cabinet, each heat exchanger can freely switch an evaporator and a condenser by controlling the second reversing device or controlling the fifth valve and the sixth valve, so that the alternate defrosting of the heat exchangers in the refrigeration display cabinet is realized, the refrigeration temperature of the refrigeration display cabinet during defrosting can be effectively maintained, the refrigeration effect during defrosting is ensured, and the reliability is ensured; and the defrosting does not influence the heating of the air conditioner indoor unit, and the air conditioner indoor unit can continuously heat. The flow direction of the refrigerant is controlled by the two schemes through the arrangement of the first reversing device and the third valve or the arrangement of the first valve, the second valve and the third valve, so that the switching between the defrosting mode and the heating mode is realized.

Example four

Based on the same inventive concept, the present embodiment provides a control device for a freezing and refrigerating apparatus, which can be applied to the freezing and refrigerating apparatus according to the embodiment of the present invention, and is used for implementing the control method for the freezing and refrigerating apparatus. The control device of the freezing and refrigerating device can be realized by software and/or hardware. The control device of the freezing and refrigerating device comprises:

the receiving module is used for receiving a defrosting instruction;

the first control module is used for controlling the bypass pipeline to communicate the exhaust port of the first compressor with the first port of the refrigerated display cabinet;

and the second control module is used for controlling at least two heat exchangers of the refrigeration display cabinet to alternately defrost.

Optionally, if a first reversing device and a third valve are arranged on the bypass pipeline, the first control module includes:

the adjusting unit is used for adjusting the frequency of the first compressor to a preset reversing frequency;

the first control unit is used for controlling the first reversing device to be communicated with the first port and the third port and opening the third valve so as to enable the refrigerant to flow from the first compressor to the refrigeration display cabinet; the first port of the first reversing device is connected to the four-way valve, the third port of the first reversing device is connected to the first end of the bypass pipeline, and the third valve is connected between the first reversing device and the second end of the bypass pipeline.

Optionally, if be provided with first valve, second valve and third valve on the bypass pipeline, first control module includes:

the second control unit is used for closing the first valve and opening the second valve and the third valve so as to enable the refrigerant to flow from the first compressor to the refrigeration showcase; the first valve is arranged on a connecting pipeline between the first end of the bypass pipeline and the outdoor heat exchanger, and the third valve is connected between the second valve and the second end of the bypass pipeline.

Optionally, the second control module is specifically configured to: closing a fourth valve, wherein a first end of the fourth valve is connected to the freezer display case throttling device corresponding to each heat exchanger, and a second end of the fourth valve is connected to an air conditioner internal unit throttling device and a refrigerated display case throttling device; when the current heat exchanger is defrosted, other heat exchangers in the at least two heat exchangers are controlled to refrigerate; and after the defrosting of the current heat exchanger is carried out for the first preset time, switching to the appointed heat exchanger for defrosting.

Optionally, if each of the at least two heat exchangers is correspondingly provided with a refrigeration showcase throttling device and a second reversing device, or each of the at least two heat exchangers is correspondingly provided with a refrigeration showcase throttling device and any two heat exchangers share the second reversing device, the second control module is specifically configured to: for the heat exchanger for defrosting, controlling a second reversing device corresponding to the heat exchanger for defrosting to communicate the heat exchanger with the bypass pipeline and not communicate the heat exchanger with a second compressor, and controlling a refrigeration display cabinet throttling device corresponding to the heat exchanger for defrosting to adjust to the maximum opening; for the heat exchanger which does not defrost, controlling a second reversing device corresponding to the heat exchanger which does not defrost to communicate the heat exchanger with a second compressor and not communicate the heat exchanger with the bypass pipeline;

under the condition that each heat exchanger is correspondingly provided with a second reversing device, a first port of the second reversing device is connected to a second end of the corresponding heat exchanger, a second port of the second reversing device is connected to a first port of the refrigeration display cabinet, and a third port of the second reversing device is connected to a suction port of the second compressor;

under the condition that any two heat exchangers share the second reversing device, the first port of the second reversing device is connected to the second end of the corresponding one of the heat exchangers, the second port of the second reversing device is connected to the first port of the refrigeration display cabinet, the third port of the second reversing device is connected to the suction port of the second compressor, the fourth port of the second reversing device is connected to the second end of the corresponding other heat exchanger, and the two heat exchangers sharing the second reversing device do not defrost at the same time.

Optionally, if each of the at least two heat exchangers is provided with a freezer display cabinet throttling device, a fifth valve and a sixth valve, the second control module is specifically configured to: for the heat exchanger for defrosting, closing the corresponding fifth valve, opening the corresponding sixth valve, and controlling the refrigeration display cabinet throttling device corresponding to the heat exchanger for defrosting to adjust to the maximum opening; and for the heat exchanger which does not defrost, opening the corresponding fifth valve and closing the corresponding sixth valve; wherein the fifth valve is connected between the second end of the corresponding heat exchanger and the suction port of the second compressor, and the sixth valve is connected between the second end of the corresponding heat exchanger and the first port of the refrigerated display cabinet.

Optionally, the control device of the freezing and refrigerating device further includes: the third control module is used for controlling the outdoor fan to keep a starting state and monitoring the outlet temperature of the outdoor heat exchanger; and when the outlet temperature of the outdoor heat exchanger is kept unchanged for a second preset time, controlling the outdoor fan to stop working.

Optionally, the control device of the freezing and refrigerating device further includes: and the fourth control module is used for adjusting the frequency of the first compressor according to the discharge pressure of the first compressor so as to enable the discharge pressure of the first compressor not to be larger than the preset pressure.

The control device of the freezing and refrigerating device can execute the method provided by the embodiment of the invention and has the corresponding functional modules and beneficial effects of the execution method. For technical details that are not described in detail in this embodiment, reference may be made to the method provided by the embodiment of the present invention.

The above-described embodiments of the control device of the freezing and refrigerating device are merely illustrative, wherein the units described as separate parts may or may not be physically separate, and the parts displayed as the units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.

EXAMPLE five

The present embodiment provides a computer-readable storage medium on which a computer program is stored, which when executed by a processor implements the control method of the freezing and refrigerating apparatus as described in the above embodiments.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A cold storage unit comprising: the refrigeration display cabinet comprises an outdoor unit, an air conditioner indoor unit, a refrigeration display cabinet and a refrigeration display cabinet, and is characterized in that the refrigeration display cabinet comprises at least two heat exchangers which are connected, and the outdoor unit is provided with a bypass pipeline;

the first end of the bypass pipeline is connected to the air outlet of the first compressor through a four-way valve, the first end of the bypass pipeline is also connected to an outdoor heat exchanger, the second end of the bypass pipeline is connected to the first port of the refrigerated display cabinet, and the at least two heat exchangers can be connected to the first port of the refrigerated display cabinet in an on-off mode;

in the defrosting mode, the air outlet of the first compressor is communicated with the first port of the refrigeration display cabinet through the bypass pipeline, and the at least two heat exchangers alternately defrost; and the exhaust port of the first compressor is communicated with the outdoor heat exchanger in the heating mode.

2. A refrigerating and freezing apparatus as claimed in claim 1, wherein a first reversing device is provided at a first end of the bypass line, a first port of the first reversing device is connected to the four-way valve, a second port of the first reversing device is connected to the outdoor heat exchanger, and a third port of the first reversing device is connected to the first end of the bypass line.

3. A cold storage unit as claimed in claim 1, wherein a first valve is provided in the connection between the first end of the bypass line and the outdoor heat exchanger, and a second valve is provided in the bypass line.

4. A cold storage device according to claim 2 or 3, wherein a third valve is provided on the bypass line, the third valve being connected between the first reversing device and the second end of the bypass line, or the third valve being connected between the second valve and the second end of the bypass line.

5. A refrigerated cold storage unit according to claim 1 wherein each of the at least two heat exchangers is provided with a refrigerated display case throttling means and a second reversing means; the refrigerated display case further comprises a second compressor, an air outlet of the second compressor being connected to an air inlet of the first compressor;

the first end of each heat exchanger in the at least two heat exchangers is connected to the first end of a fourth valve through a corresponding freezer display case throttling device, and the second end of the fourth valve is connected to an air conditioner internal unit throttling device and a refrigerated display case throttling device;

the second end of each heat exchanger in the at least two heat exchangers is connected to the first port of the corresponding second reversing device, the second port of the second reversing device is connected to the first port of the refrigerated display cabinet, and the third port of the second reversing device is connected to the suction port of the second compressor.

6. A refrigerated cold storage unit as claimed in claim 5 wherein any two of the at least two heat exchangers share a second reversing device, the second end of one of the at least two heat exchangers being connected to the first port of a corresponding second reversing device, the second port of the corresponding second reversing device being connected to the first port of the refrigerated display case, the third port of the corresponding second reversing device being connected to the suction of the second compressor, and the fourth port of the corresponding second reversing device being connected to the second end of another of the at least two heat exchangers.

7. A refrigerated merchandiser as recited in claim 1 wherein each of said at least two heat exchangers is provided with a refrigerated merchandiser throttling device, a fifth valve and a sixth valve; the refrigerated display case further comprises a second compressor, an air outlet of the second compressor being connected to an air inlet of the first compressor;

the second end of each of the at least two heat exchangers is connected to the suction port of the second compressor through a respective fifth valve, and the second end of each heat exchanger is also connected to the first port of the refrigerated display cabinet through a respective sixth valve.

8. A control method of a freezing and refrigerating apparatus, which is applied to the freezing and refrigerating apparatus according to any one of claims 1 to 7, comprising:

receiving a defrosting instruction;

the control bypass pipeline is communicated with an exhaust port of the first compressor and a first port of the refrigeration display cabinet;

at least two heat exchangers of the freezing showcase are controlled to alternately defrost.

9. The method of claim 8 wherein controlling the bypass line to communicate the discharge of the first compressor with the first port of the refrigerated display case if the bypass line is provided with the first reversing device and the third valve comprises:

adjusting the frequency of the first compressor to a preset reversing frequency;

controlling the first reversing device to communicate the first port and the third port, and opening the third valve to enable the refrigerant to flow from the first compressor to the refrigeration display cabinet;

the first port of the first reversing device is connected to a four-way valve, the third port of the first reversing device is connected to the first end of the bypass pipeline, and the third valve is connected between the first reversing device and the second end of the bypass pipeline.

10. The method of claim 8 wherein controlling the bypass line to communicate the discharge of the first compressor with the first port of the refrigerated display case if the bypass line has the first valve, the second valve, and the third valve comprises:

closing the first valve, and opening the second valve and the third valve to enable the refrigerant to flow from the first compressor to the refrigerated display cabinet;

wherein the first valve is disposed on a connection pipeline between a first end of the bypass pipeline and the outdoor heat exchanger, and the third valve is connected between the second valve and a second end of the bypass pipeline.

11. The method of claim 8 wherein controlling at least two heat exchangers of a refrigerated display case for alternate defrosting comprises:

closing a fourth valve, wherein a first end of the fourth valve is connected to the freezer display case throttling device corresponding to each heat exchanger, and a second end of the fourth valve is connected to an air conditioner internal unit throttling device and a refrigerated display case throttling device;

when the current heat exchanger is defrosted, other heat exchangers in the at least two heat exchangers are controlled to refrigerate;

and after the defrosting of the current heat exchanger is carried out for the first preset time, switching to the appointed heat exchanger for defrosting.

12. The method according to claim 8, wherein if each of the at least two heat exchangers is provided with a refrigeration showcase throttling device and a second reversing device correspondingly, or each of the at least two heat exchangers is provided with a refrigeration showcase throttling device correspondingly and any two heat exchangers share the second reversing device, controlling the at least two heat exchangers of the refrigeration showcase to alternately defrost comprises:

for the heat exchanger for defrosting, controlling a second reversing device corresponding to the heat exchanger for defrosting to communicate the heat exchanger with the bypass pipeline and not communicate the heat exchanger with a second compressor, and controlling a refrigeration display cabinet throttling device corresponding to the heat exchanger for defrosting to adjust to the maximum opening;

for the heat exchanger which does not defrost, controlling a second reversing device corresponding to the heat exchanger which does not defrost to communicate the heat exchanger with a second compressor and not communicate the heat exchanger with the bypass pipeline;

13. The method of claim 8, wherein controlling the at least two heat exchangers of the refrigerated display case to alternately defrost if each of the at least two heat exchangers is provided with a refrigerated display case throttling device, a fifth valve, and a sixth valve comprises:

for the heat exchanger which does not defrost, opening the corresponding fifth valve and closing the corresponding sixth valve;

wherein the fifth valve is connected between the second end of the corresponding heat exchanger and the suction port of the second compressor, and the sixth valve is connected between the second end of the corresponding heat exchanger and the first port of the refrigerated display cabinet.

14. The method of claim 8, further comprising, after controlling the bypass line to communicate the discharge of the first compressor with the first port of the refrigerated display case:

controlling an outdoor fan to keep a starting state and monitoring the outlet temperature of an outdoor heat exchanger;

and when the outlet temperature of the outdoor heat exchanger is kept unchanged for a second preset time, controlling the outdoor fan to stop working.

15. The method of claim 8, further comprising, after controlling the bypass line to communicate the discharge of the first compressor with the first port of the refrigerated display case:

and adjusting the frequency of the first compressor according to the discharge pressure of the first compressor so that the discharge pressure of the first compressor is not greater than a preset pressure.

16. A control device for a refrigerating and cold storage device, which is applied to the refrigerating and cold storage device according to any one of claims 1 to 7, comprising:

the receiving module is used for receiving a defrosting instruction;

17. A computer-readable storage medium, on which a computer program is stored, which program, when being executed by a processor, carries out the method according to any one of claims 8-15.