CN117847821A - Self-cascade heat pump circulation system and control method thereof - Google Patents

Abstract

The invention provides a self-cascade heat pump circulation system, which comprises: the device comprises a compressor, a four-way valve, an indoor heat exchanger, an outdoor heat exchanger and a self-cascade heat exchange pipeline; the indoor heat exchanger is provided with an indoor heat exchanger A port and an indoor heat exchanger B port which are communicated with each other; the outdoor heat exchanger is provided with an outdoor heat exchanger A port and an outdoor heat exchanger B port which are communicated with each other; the exhaust port of the compressor is selectively communicated with an indoor heat exchanger A port or an outdoor heat exchanger A port through a four-way valve, the indoor heat exchanger B port and the outdoor heat exchanger B port are respectively communicated with an inlet of a self-cascade heat exchange pipeline, and an outlet of the self-cascade heat exchange pipeline is communicated with an air inlet of the compressor; the self-cascade heat exchange pipeline is used for further cooling the refrigerant during refrigeration or further heating the refrigerant during heating. According to the invention, a control component of a load is not needed, and the switching between a heating mode and a refrigerating mode can be realized through the four-way valve, so that the method is simpler and more reliable.

Description

Self-cascade heat pump circulation system and control method thereof

Technical Field

The invention relates to the technical field of self-cascade heat pump circulation systems, in particular to a self-cascade heat pump circulation system and a control method of the self-cascade heat pump circulation system.

Background

Because of the limitation of evaporation pressure and condensation pressure, the same refrigerant is difficult to prepare low temperature at normal temperature, and a cascade system is often used, the principle of the cascade refrigeration system is as follows: the self-cascade effect in the refrigeration cycle is utilized to improve the refrigeration effect.

However, the existing self-cascade system can only realize a refrigeration effect through a double pipeline, has single function, and needs to be additionally provided with a plurality of control switches to switch the pipeline when heating is needed, so that the conversion control is complex, and the reliability of the system is reduced.

Disclosure of Invention

The present application is based on the discovery and recognition by the inventors of the following problems and facts: the existing self-cascade heat pump circulation system is complicated in control of switching between refrigerating and heating modes and low in reliability.

The present invention aims to solve at least to some extent one of the above technical problems.

According to a first aspect of the present disclosure, there is provided a self-cascade heat pump cycle comprising: the device comprises a compressor, a four-way valve, an indoor heat exchanger, an outdoor heat exchanger, a first gas-liquid separator, a first expansion valve, an evaporative condenser, a first one-way valve, a second gas-liquid separator, a second expansion valve and a second one-way valve;

the indoor heat exchanger is provided with a passage L, and the passage L is provided with an indoor heat exchanger A port and an indoor heat exchanger B port;

the outdoor heat exchanger is provided with a passage L, and the passage L is provided with an outdoor heat exchanger A port and an outdoor heat exchanger B port;

the evaporator condenser is provided with a passage L and a passage L, heat exchange can be carried out between the passage L and the passage L, the passage L is provided with an evaporator condenser A port and an evaporator condenser B port, the passage L is provided with an evaporator condenser C port and an evaporator condenser D port, the evaporator condenser A port is communicated with the evaporator condenser B port, and the evaporator condenser C port is communicated with the evaporator condenser D port;

the first gas-liquid separator is provided with a first gas-liquid separator A port, a first gas-liquid separator B port and a first gas-liquid separator gas outlet;

the second gas-liquid separator is provided with a second gas-liquid separator A port, a second gas-liquid separator B port and a second gas-liquid separator gas outlet;

the four-way valve is provided with a four-way valve A port, a four-way valve B port, a four-way valve C port and a four-way valve D port, wherein the four-way valve A port is communicated with the four-way valve D port and the four-way valve C port is communicated with the four-way valve B port, or the four-way valve A port is communicated with the four-way valve B port and the four-way valve C port is communicated with the four-way valve D port;

the exhaust port of the compressor is communicated with the port D of the four-way valve, the port A of the four-way valve is communicated with the port A of the indoor heat exchanger and the outlet of the first one-way valve, the port C of the four-way valve is communicated with the port A of the outdoor heat exchanger and the outlet of the second one-way valve, the port B of the indoor heat exchanger is communicated with the port A of the first gas-liquid separator, the outlet of the first gas-liquid separator is communicated with the port A of the evaporation condenser, the port A of the evaporation condenser is also communicated with the inlet of the first one-way valve, the port B of the evaporation condenser is communicated with the port B of the second expansion valve, the port D of the evaporation condenser is communicated with the inlet of the second one-way valve, the outlet of the second expansion valve is communicated with the port A of the second gas-liquid separator, the port B of the second gas-liquid separator is communicated with the port B of the outdoor heat exchanger, and the outlet of the second gas-liquid separator is communicated with the inlet of the second one-way valve.

In some embodiments, the four-way valve a port is communicated with the four-way valve D port, and the four-way valve C port is in a heating mode when communicated with the four-way valve B port;

the four-way valve A is communicated with the four-way valve B, and the four-way valve C is in a refrigerating mode when communicated with the four-way valve D.

In some embodiments, further comprising: a third gas-liquid separator;

the third gas-liquid separator is provided with a third gas-liquid separator inlet and a third gas-liquid separator outlet;

and the inlet of the third gas-liquid separator is communicated with the port B of the four-way valve, and the outlet of the third gas-liquid separator is communicated with the air inlet of the compressor.

In some embodiments, a first auxiliary throttling device is arranged on a pipeline between an inlet of the first one-way valve and an A port of the evaporative condenser;

and a second auxiliary throttling device is arranged on a pipeline between the inlet of the second one-way valve and the D port of the evaporative condenser.

In some embodiments, further comprising:

defrosting pipelines of the outdoor heat exchanger;

the outdoor heat exchanger defrost line includes: an electric control valve;

the outdoor heat exchanger is also provided with an outdoor heat exchanger C port and an outdoor heat exchanger D port which are communicated with each other;

the inlet of the electric control valve is communicated with the air outlet of the first gas-liquid separator, the outlet of the electric control valve is communicated with the C port of the outdoor heat exchanger, and the D port of the outdoor heat exchanger is communicated with the C port of the four-way valve.

In some embodiments, further comprising: further comprises:

a controller, a first temperature sensor and a second temperature sensor;

the first temperature sensor is arranged on the outer surface of the indoor heat exchanger, and the second temperature sensor is arranged on the outer surface of the outdoor heat exchanger;

the controller is respectively and electrically connected with the first temperature sensor, the second temperature sensor, the four-way valve and the electric control valve;

the controller is used for controlling the four-way valve switching connection port based on the temperature signal of the first temperature sensor so as to switch a refrigerating mode and a heating mode;

the controller is used for controlling the switch of the electric control valve based on the temperature signal of the second temperature sensor so as to switch the defrosting pipeline of the outdoor heat exchanger.

An embodiment according to a second aspect of the present invention provides an air conditioner, including:

the self-cascade heat pump cycle system.

An embodiment according to a third aspect of the present invention provides a control method of a self-cascade heat pump cycle system, including: acquiring the surface temperature of an indoor heat exchanger;

if the surface temperature of the indoor heat exchanger is greater than a first preset value, starting a refrigeration mode;

and if the surface temperature of the indoor heat exchanger is smaller than or equal to a first preset value, starting a heating mode.

In some embodiments, the surface temperature of the outdoor heat exchanger is obtained if in the heating mode;

if the surface temperature of the outdoor heat exchanger is higher than the frosting temperature, the defrosting pipeline of the outdoor heat exchanger is not started;

and if the surface temperature of the outdoor heat exchanger is smaller than or equal to the frosting temperature, starting a defrosting pipeline of the outdoor heat exchanger until the surface temperature of the outdoor heat exchanger is larger than the frosting temperature, and closing the defrosting pipeline of the outdoor heat exchanger.

In some embodiments, closing the outdoor heat exchanger defrost line until the surface temperature of the outdoor heat exchanger is greater than the frosting temperature comprises:

and when the surface temperature of the outdoor heat exchanger is higher than the frosting temperature, starting timing, and closing the defrosting pipeline of the outdoor heat exchanger after the preset time is reached.

According to the self-cascade heat pump circulation system provided by the embodiment of the invention, the exhaust port of the compressor can be selectively communicated with the indoor heat exchanger A port or the outdoor heat exchanger A port through the four-way valve, so that the high-temperature and high-pressure refrigerant discharged from the compressor can be selected to have two different flow paths under the control of the four-way valve, when the refrigerant firstly enters the indoor heat exchanger A port through the four-way valve, then enters the self-cascade pipeline through the indoor heat exchanger B port, then enters the outdoor heat exchanger B port from the self-cascade pipeline, finally returns to the air inlet of the compressor from the outdoor heat exchanger A port, heating can be performed, when the refrigerant firstly enters the self-cascade pipeline through the four-way valve, then enters the indoor heat exchanger B port from the self-cascade pipeline, finally returns to the air inlet of the compressor from the indoor heat exchanger A port, the switching of the heating and refrigerating pipeline can be realized through the simple four-way valve, when the pipeline is switched, the switching of the four-way valve is not needed, the switching structure is more simple, and the switching structure is more convenient, and the switching structure is more is needed.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

FIG. 1 is a schematic diagram of a structure according to one embodiment of the invention;

fig. 2 is a schematic view of a refrigerant flow direction structure of a heating mode according to an embodiment of the present invention;

fig. 3 is a schematic diagram of a refrigerant flow direction structure in a cooling mode according to an embodiment of the present invention.

Reference numerals

1. A compressor; 2. a four-way valve; 3. an outdoor heat exchanger; 4. a second gas-liquid separator; 5. a second expansion valve; 6. an evaporative condenser; 7. a first auxiliary throttle device; 8. a first one-way valve; 9. a first expansion valve; 10. a first gas-liquid separator; 11. an indoor heat exchanger; 12. a third gas-liquid separator; 13. a second auxiliary throttle device; 14. a second one-way valve; 15. an electrically controlled valve.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

Throughout the specification and claims, the following terms have at least the meanings explicitly associated herein, unless the context dictates otherwise. The meanings identified below are not necessarily limiting terms, but merely provide illustrative examples of terms.

In the description of the present invention, the phrase "in one embodiment" does not necessarily refer to the same embodiment, although it may. Similarly, the phrase "in some embodiments" as used herein, when used multiple times, does not necessarily refer to the same embodiment, although it may. As used herein, the term "or" is an inclusive "or" operator and is equivalent to the term "and/or" unless the context clearly dictates otherwise. The term "based on" is not exclusive and allows for being based on additional factors not described, unless the context clearly dictates otherwise. The term "exemplary" is used herein to mean "serving as an example, instance, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. The scope of the invention is limited only by the scope of the appended claims, and any examples set forth in this specification are not intended to be limiting, but merely set forth some of the many possible embodiments of the claimed invention. The various embodiments provided by the present invention should not be construed as limiting the scope of the invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

The self-cascade heat pump cycle system has become one of the indispensable household appliances in daily life along with the improvement of the living standard of people, and the self-cascade heat pump cycle system generally has a refrigerating mode and a heating mode, and can enable the indoor room to be at a comfortable environment temperature through the adjustment of the room temperature.

On the one hand, in the self-cascade heat pump circulation system in the prior art, although the air at the air outlet 2 can be heated by auxiliary electric heating, the heating effect of the self-cascade heat pump circulation system is improved when the self-cascade heat pump circulation system is in a heating mode, but the auxiliary electric heating can shield the air outlet 2 when the air conditioner is in a cooling mode, so that the cooling effect of the self-cascade heat pump circulation system is affected.

Based on this, as shown in fig. 1 to 3, the self-cascade heat pump cycle according to the embodiment of the present invention includes: the air conditioner comprises a compressor 1, a four-way valve 2, an indoor heat exchanger 11, an outdoor heat exchanger 3, a first gas-liquid separator 10, a first expansion valve 9, an evaporative condenser 6, a first one-way valve 8, a second gas-liquid separator 4, a second expansion valve 5 and a second one-way valve 14;

the indoor heat exchanger 11 has a passage L1, the passage L1 having an indoor heat exchanger 11A port and an indoor heat exchanger 11B port;

the outdoor heat exchanger 3 has a passage L2, and the passage L2 has an outdoor heat exchanger 3A port and an outdoor heat exchanger 3B port;

the evaporation condenser 6 has a passage L3 and a passage L4, heat exchange is possible between the passage L3 and the passage L4, the passage L3 has an evaporation condenser 6A port and an evaporation condenser 6B port, the passage L4 has an evaporation condenser 6C port and an evaporation condenser 6D port, the evaporation condenser 6A port communicates with the evaporation condenser 6B port, and the evaporation condenser 6C port communicates with the evaporation condenser 6D port;

the first gas-liquid separator 10 has a first gas-liquid separator 10A port, a first gas-liquid separator 10B port, and a first gas-liquid separator 10 gas outlet port;

the second gas-liquid separator 4 is provided with a second gas-liquid separator 4A port, a second gas-liquid separator 4B port and a second gas-liquid separator 4 gas outlet;

the four-way valve 2 is provided with a four-way valve 2A port, a four-way valve 2B port, a four-way valve 2C port and a four-way valve 2D port, wherein the four-way valve 2A port is communicated with the four-way valve 2D port and the four-way valve 2C port is communicated with the four-way valve 2B port, or the four-way valve 2A port is communicated with the four-way valve 2B port and the four-way valve 2C port is communicated with the four-way valve 2D port;

the exhaust port of the compressor 1 is communicated with a four-way valve 2D port, a four-way valve 2A port is communicated with an indoor heat exchanger 11A port and an outlet of a first one-way valve 8, a four-way valve 2C port is communicated with an outdoor heat exchanger 3A port and an outlet of a second one-way valve 14, an indoor heat exchanger 11B port is communicated with a first gas-liquid separator 10A port, an air outlet of the first gas-liquid separator 10 is communicated with an evaporation condenser 6A port, the evaporation condenser 6A port is also communicated with an air inlet of the first one-way valve 8, an evaporation condenser 6B port is communicated with an inlet of a second expansion valve 5, an evaporation condenser 6C port is communicated with an inlet of the first gas-liquid separator 4B port, an outlet of the second expansion valve 5 is communicated with the second gas-liquid separator 4A port, the second gas-liquid separator 4B port is communicated with an outdoor heat exchanger 3B port, and an air outlet of the second gas-liquid separator 4 is communicated with an inlet of the second one-way valve 14.

Specifically, the self-cascade heat exchange pipeline utilizes the self-cascade effect of refrigerant circulation, when the refrigerant is used for heating, the heat of the refrigerant can be further improved through the self-cascade heat exchange pipeline or the temperature of the refrigerant can be further reduced through the self-cascade pipeline when the refrigerant is used for refrigerating, so that the self-cascade heat pump circulation system provided by the system can have a better temperature control effect, can reach a lower temperature during refrigerating, and can reach a higher temperature during heating.

The exhaust port of the compressor 1 is communicated with the four-way valve 2 firstly, then the four-way valve 2 is communicated with the indoor heat exchanger 11A or the outdoor heat exchanger 3A, when the compressor 1 is communicated with the indoor heat exchanger 11 firstly through the four-way valve 2, a refrigerant compressed by the compressor 1 passes through the indoor heat exchanger 11 firstly, then enters a self-cascade heat exchange pipeline, enters the outdoor heat exchanger 3 from the self-cascade heat exchange pipeline and finally returns to the compressor 1 to perform heating, when the compressor 1 is communicated with the outdoor heat exchanger 3 firstly through the four-way valve, the refrigerant compressed by the compressor 1 passes through the outdoor heat exchanger 3 firstly, then enters the self-cascade heat exchange pipeline, then enters the indoor heat exchanger 11 from the self-cascade heat exchange pipeline, finally returns to the compressor 1 to perform cooling, and the same double-pipe equipment can have two functions of cooling and heating.

Moreover, through cross valve 2 and corresponding pipeline setting, can make the application put forward from cascade heat transfer pipeline realize refrigerating and the quick switch of heating, when carrying out the pipeline switch, only need switch the valve way in the cross valve 2, need not carry out too much control to other pipelines, need not increase very many change over switches, change over control structure is simpler, can have better reliability.

Specifically, during heating, the gaseous refrigerant separated by the first gas-liquid separator 10 enters from the port of the evaporation condenser 6A, and is discharged from the port of the evaporation condenser 6B, while the liquid refrigerant enters from the port of the evaporation condenser 6C, and is discharged from the port of the evaporation condenser 6D; during refrigeration, the gaseous refrigerant separated by the second gas-liquid separator 4 enters from the port of the evaporation condenser 6D, is discharged from the port of the evaporation condenser 6C, and the liquid refrigerant enters from the port of the evaporation condenser 6B, is discharged from the port of the evaporation condenser 6A, and can realize heat exchange or exchange of the refrigerant by the evaporation condenser 6, so that the refrigerant is further cooled or further heated by the self-cascade effect, and further the refrigeration or heating effect is improved.

The refrigerant in the first check valve 8 and the second check valve 14 can only flow from the inlet to the outlet, and can be matched with the four-way valve 2, so that the refrigerant is prevented from flowing reversely when the four-way valve 2 switches a heating or refrigerating circuit.

As shown in fig. 2, the arrow direction is the flow direction of the refrigerant in the heating mode, and as shown in fig. 3, the arrow direction is the flow direction of the refrigerant in the cooling mode.

The refrigerant circulating in the self-cascade heat exchange pipeline can be a non-azeotropic refrigerant, generally, the refrigerant is formed by mixing two or more refrigerants, and the refrigerant can be mixed by R600a and R1150, or can be mixed by R600a, R23 and R14.

According to the self-cascade heat pump cycle system provided by the embodiment of the invention, the exhaust port of the compressor 1 can be selectively communicated with the indoor heat exchanger 11A port or the outdoor heat exchanger 3A port through the four-way valve 2, so that the high-temperature and high-pressure refrigerant discharged from the compressor 1 can be selected to have two different flow paths under the control of the four-way valve 2, when the refrigerant firstly enters the indoor heat exchanger 11A port through the four-way valve 2, then enters the self-cascade pipeline through the indoor heat exchanger 11B port, then enters the outdoor heat exchanger 3B port through the self-cascade pipeline, finally enters the outdoor heat exchanger 3A port through the outdoor heat exchanger 3A port, then enters the self-cascade pipeline through the outdoor heat exchanger 3B port, then enters the indoor heat exchanger 11B port through the self-cascade pipeline, and finally returns to the air inlet of the compressor 1 through the indoor heat exchanger 11A port, the refrigerant can be refrigerated, the switching valve can be realized through the simple four-way valve 2, the switching valve can be realized, the switching valve can be changed in a more simple way, the switching valve can be changed in a more than the switching valve, and the switching valve is not needed, and the switching valve can be changed in other structures, and the switching valve can be changed more than the switching valve is needed.

In some embodiments, four-way valve 2 is provided with four-way valve 2A port, four-way valve 2B port, four-way valve 2C port, and four-way valve 2D port;

the port of the four-way valve 2A is communicated with the port of the indoor heat exchanger 11A and the outlet of the first one-way valve 8, the port of the four-way valve 2B is communicated with the air inlet of the compressor 1, the port of the four-way valve 2C is communicated with the port of the outdoor heat exchanger 3A and the outlet of the second one-way valve 14, and the port of the four-way valve 2D is communicated with the air outlet of the compressor 1;

wherein, the four-way valve 2A port is communicated with the four-way valve 2D port or communicated with the four-way valve 2B port, and the four-way valve 2C port is communicated with the four-way valve 2B port or communicated with the four-way valve 2D port;

wherein, under heating mode, four-way valve 2A mouth and four-way valve 2D mouth intercommunication, four-way valve 2C mouth and four-way valve 2B mouth intercommunication, under cooling mode, four-way valve 2A mouth and four-way valve 2B mouth intercommunication, four-way valve 2C mouth and four-way valve 2D mouth intercommunication.

Specifically, the four-way valve 2A port, the four-way valve 2B port, the four-way valve 2C port and the four-way valve 2D port can change the flow direction of the refrigerant by switching the internal loop, thereby realizing the switching of the heating pipeline and the refrigerating pipeline.

In some embodiments, further comprising: a third gas-liquid separator 12;

the third gas-liquid separator 12 is provided with a third gas-liquid separator 12 inlet and a third gas-liquid separator 12 outlet;

the inlet of the third gas-liquid separator 12 is communicated with the port of the four-way valve 2B, and the outlet of the third gas-liquid separator 12 is communicated with the air inlet of the compressor 1.

Specifically, the three gas-liquid separators are arranged at the air inlet of the compressor 1, so that the refrigerant entering the compressor 1 can be filtered, and the phenomenon that the normal operation of the compressor 1 is influenced due to the fact that liquid refrigerant enters the compressor 1 is avoided.

In some embodiments, the line between the inlet of the first non-return valve 8 and the inlet of the evaporative condenser 6A is provided with a first auxiliary throttling device 7;

the line between the inlet of the second non-return valve 14 and the opening of the evaporative condenser 6D is provided with a second auxiliary throttle device 13.

Specifically, the first auxiliary throttling device 7 and the second auxiliary throttling device 13 may be capillary segments respectively, the first auxiliary throttling device 7 and the second auxiliary throttling device 13 may achieve the functions of throttling and decompressing, so that the pressures at the first check valve 8 and the second check valve 13 are the same as the pressure of the outdoor heat exchanger 3 respectively, and when the pressure of the refrigerant is reduced from the condensing pressure to the evaporating pressure, the refrigerant is converted into a gaseous state when entering the compressor 1, more refrigerant may flow back to the compressor 1, and the working efficiency of the whole refrigeration or heating system can be improved.

In some embodiments, the outdoor heat exchanger 3 defrost line;

the defrosting line of the outdoor heat exchanger 3 includes: an electric control valve;

the outdoor heat exchanger 3 is also provided with an outdoor heat exchanger 3C port and an outdoor heat exchanger 3D port which are communicated with each other;

the inlet of the electric control valve is communicated with the air outlet of the first gas-liquid separator 10, the outlet of the electric control valve is communicated with the opening of the outdoor heat exchanger 3C, and the opening of the outdoor heat exchanger 3D is communicated with the opening of the four-way valve 2C.

Specifically, the electric control valve can control whether the outdoor heat exchanger 3 is communicated with the air outlet of the first gas-liquid separator 10, when the opening of the outdoor heat exchanger 3C is communicated with the air outlet of the first separator, a part of gaseous refrigerant can enter the outdoor heat exchanger 3 to heat the outdoor heat exchanger 3, the temperature of the outdoor heat exchanger 3 is improved, frosting of the outdoor heat exchanger 3 can be avoided, and the heat exchange efficiency of the outdoor heat exchanger 3 is affected.

In some embodiments, further comprising:

a controller, a first temperature sensor and a second temperature sensor;

the first temperature sensor is arranged on the outer surface of the indoor heat exchanger 11, and the second temperature sensor is arranged on the outer surface of the outdoor heat exchanger 3;

the controller is respectively and electrically connected with the first temperature sensor, the second temperature sensor, the four-way valve 2 and the electric control valve;

the controller is used for controlling the four-way valve 2 to switch the connecting port based on the temperature signal of the first temperature sensor so as to switch the refrigerating mode and the heating mode;

the controller is used for controlling the switch of the electric control valve based on the temperature signal of the second temperature sensor so as to switch the defrosting pipeline of the outdoor heat exchanger 3.

Specifically, the controller can control the connection port of the four-way valve 2 to switch, so that the four-way valve 2A port is communicated with the four-way valve 2D port, the four-way valve 2C port is communicated with the four-way valve 2B port, or the four-way valve 2A port is communicated with the four-way valve 2B port, and the four-way valve 2C port is communicated with the four-way valve 2D port, so that a heating mode or a refrigerating mode is switched.

The controller can control the electric control valve, the electric control valve is opened or closed, the electric control valve is opened, the defrosting pipeline of the outdoor heat exchanger 3 can be started, and defrosting is carried out on the outdoor heat exchanger 3.

The controller is connected with the first temperature sensor and the second temperature sensor respectively, can receive and control the temperature signal of the first temperature sensor and the second temperature sensor, the first temperature sensor is arranged on the surface of the indoor heat exchanger 11, can monitor the indoor temperature, enables the controller to start a heating mode when the temperature is lower, and starts a refrigerating mode when the temperature is higher, and the second temperature sensor is arranged on the surface of the outdoor heat exchanger 3, monitors the surface temperature of the outdoor heat exchanger 3, enables the controller to reach frosting temperature of the outdoor heat exchanger 3, and automatically opens the electric control valve when frosting begins to heat the outdoor heat exchanger 3, so that frosting of the outdoor heat exchanger 3 is avoided, and heat exchange efficiency is influenced.

The embodiment of the application also provides an air conditioner, which comprises: the self-cascade heat pump cycle system.

Specifically, through the self-cascade heat pump circulation system that this application provided, not only can make the heat exchange efficiency of air conditioner better, still through cross valve 2 and pipeline setting for making the air conditioner can be simple swift switch refrigeration mode and heating mode, make the air conditioner have better reliability.

The embodiment of the application also provides a control method of the self-cascade heat pump circulation system, which comprises the following steps:

acquiring the surface temperature of the indoor heat exchanger 11;

if the surface temperature of the indoor heat exchanger 11 is greater than a first preset value, starting a refrigeration mode;

if the surface temperature of the indoor heat exchanger 11 is less than or equal to the first preset value, the heating mode is started.

Specifically, the surface temperature of the indoor heat exchanger 11 can be obtained through the first temperature sensor, and the temperature of the surface of the indoor heat exchanger 11 can reflect the heat or cold of the indoor space.

The first preset value may be a temperature value input by a user, when the surface temperature of the indoor heat exchanger 11 is higher than the first preset value, the controller controls the four-way valve 2 to switch the connection port, so that the cooling mode can be started, and when the surface temperature of the indoor heat exchanger 11 is lower than the first preset value, the controller controls the four-way valve 2 to switch the connection port, so that the heating mode can be started.

In some embodiments, the surface temperature of the outdoor heat exchanger 3 is obtained if in the heating mode;

if the surface temperature of the outdoor heat exchanger 3 is higher than the frosting temperature, the defrosting pipeline of the outdoor heat exchanger 3 is not started;

and if the surface temperature of the outdoor heat exchanger 3 is less than or equal to the frosting temperature, starting the defrosting pipeline of the outdoor heat exchanger 3 until the surface temperature of the outdoor heat exchanger 3 is greater than the frosting temperature, and closing the defrosting pipeline of the outdoor heat exchanger 3.

Specifically, when the heating mode is performed, the temperature of the outdoor heat exchanger 3 is reduced, and when the temperature of the outdoor heat exchanger 3 is reduced to the frosting temperature, frosting begins, a large amount of frosting on the surface of the outdoor heat exchanger 3 affects the heat exchange efficiency of the outdoor heat exchanger 3, and further affects the heating efficiency of the whole self-cascade heat pump circulation system, the surface temperature of the outdoor heat exchanger 3 can be obtained through the second temperature sensor, a temperature signal is transmitted to the controller, the controller can start the electric control valve when the surface temperature of the outdoor heat exchanger 3 reaches the frosting temperature, the defrosting pipeline of the outdoor heat exchanger 3 is opened through the electric control valve, so that part of gaseous refrigerant in the first gas-liquid separator 10 enters the outdoor heat exchanger 3, the temperature of the outdoor heat exchanger 3 is increased, and frosting of the outdoor heat exchanger 3 is avoided.

In some embodiments, closing the defrost line of the outdoor heat exchanger 3 until the surface temperature of the outdoor heat exchanger 3 is greater than the frosting temperature, comprises:

when the surface temperature of the outdoor heat exchanger 3 is higher than the frosting temperature, starting timing, and closing the defrosting pipeline of the outdoor heat exchanger 3 after the preset time is reached.

Specifically, when the temperature of the outdoor heat exchanger 3 is increased through the defrosting pipeline of the outdoor heat exchanger 3, when the temperature of the outdoor heat exchanger 3 is higher than the frosting temperature, the defrosting pipeline of the outdoor heat exchanger 3 is not closed immediately, and the outdoor heat exchanger 3 is continuously heated for a period of time after timing is started, and then the defrosting pipeline of the outdoor heat exchanger 3 is closed after the preset time, so that the phenomenon that the surface temperature of the outdoor heat exchanger 3 is lifted up and down at the frosting temperature, and the defrosting pipeline is frequently started and stopped to influence the stability of the whole self-cascade heat pump circulation system can be avoided.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Further, one skilled in the art can engage and combine the different embodiments or examples described in this specification.

While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims (10)

1. A self-cascade heat pump cycle comprising:

the device comprises a compressor (1), a four-way valve (2), an indoor heat exchanger (11), an outdoor heat exchanger (3), a first gas-liquid separator (10), a first expansion valve (9), an evaporation condenser (6), a first one-way valve (8), a second gas-liquid separator (4), a second expansion valve (5) and a second one-way valve (14);

the indoor heat exchanger (11) is provided with a passage L1, and the passage L1 is provided with an indoor heat exchanger (11) A port and an indoor heat exchanger (11) B port;

the outdoor heat exchanger (3) is provided with a passage L2, and the passage L2 is provided with an A port of the outdoor heat exchanger (3) and a B port of the outdoor heat exchanger (3);

the evaporation condenser (6) is provided with a passage L3 and a passage L4, heat exchange can be carried out between the passage L3 and the passage L4, the passage L3 is provided with an evaporation condenser (6) A port and an evaporation condenser (6) B port, the passage L4 is provided with an evaporation condenser (6) C port and an evaporation condenser (6) D port, the evaporation condenser (6) A port is communicated with the evaporation condenser (6) B port, and the evaporation condenser (6) C port is communicated with the evaporation condenser (6) D port;

the first gas-liquid separator (10) is provided with a first gas-liquid separator (10) A port, a first gas-liquid separator (10) B port and a first gas-liquid separator (10) gas outlet;

the second gas-liquid separator (4) is provided with a second gas-liquid separator (4) A port, a second gas-liquid separator (4) B port and a second gas-liquid separator (4) gas outlet;

the four-way valve (2) is provided with a four-way valve (2) A port, a four-way valve (2) B port, a four-way valve (2) C port and a four-way valve (2) D port, wherein the four-way valve (2) A port is communicated with the four-way valve (2) D port and the four-way valve (2) C port is communicated with the four-way valve (2) B port, or the four-way valve (2) A port is communicated with the four-way valve (2) B port and the four-way valve (2) C port is communicated with the four-way valve (2) D port;

the exhaust port of the compressor (1) is communicated with the port D of the four-way valve (2), the port A of the four-way valve (2) is communicated with the port A of the indoor heat exchanger (11) and the outlet of the first one-way valve (8), the port C of the four-way valve (2) is communicated with the port A of the outdoor heat exchanger (3) and the outlet of the second one-way valve (14), the port B of the indoor heat exchanger (11) is communicated with the port A of the first gas-liquid separator (10), the gas outlet of the first gas-liquid separator (10) is communicated with the port A of the evaporative condenser (6), the port A of the evaporative condenser (6) is also communicated with the gas inlet of the first one-way valve (8), the port B of the evaporative condenser (6) is communicated with the inlet of the second expansion valve (5), the port C of the evaporative condenser (6) is communicated with the port B of the first one-way valve (4), the port D of the evaporative condenser (6) is communicated with the inlet of the second one-way valve (14), and the inlet of the second one-way valve (4) is communicated with the inlet of the second one-way valve (4).

2. A self-cascade heat pump cycle system as recited in claim 1, wherein,

the four-way valve (2) A is communicated with the four-way valve (2) D, and the four-way valve (2) C is in a heating mode when communicated with the four-way valve (2) B;

the four-way valve (2) A is communicated with the four-way valve (2) B, and the four-way valve (2) C is in a refrigerating mode when communicated with the four-way valve (2) D.

3. A self-cascade heat pump cycle system as recited in claim 1, wherein,

further comprises: a third gas-liquid separator (12);

the third gas-liquid separator (12) is provided with a third gas-liquid separator (12) inlet and a third gas-liquid separator (12) outlet;

the inlet of the third gas-liquid separator (12) is communicated with the port B of the four-way valve (2), and the air outlet of the third gas-liquid separator (12) is communicated with the air inlet of the compressor (1).

4. A self-cascade heat pump cycle system as recited in claim 1, wherein,

a first auxiliary throttling device (7) is arranged on a pipeline between the inlet of the first one-way valve (8) and the A port of the evaporative condenser (6);

a second auxiliary throttling device (13) is arranged on a pipeline between the inlet of the second one-way valve (14) and the D port of the evaporative condenser (6).

5. A self-cascade heat pump cycle as recited in claim 1, further comprising:

a defrosting pipeline of the outdoor heat exchanger (3);

the defrosting pipeline of the outdoor heat exchanger (3) comprises: an electric control valve;

the outdoor heat exchanger (3) is also provided with an outdoor heat exchanger (3) C port and an outdoor heat exchanger (3) D port which are communicated with each other;

the inlet of the electric control valve is communicated with the air outlet of the first gas-liquid separator (10), the outlet of the electric control valve is communicated with the C port of the outdoor heat exchanger (3), and the D port of the outdoor heat exchanger (3) is communicated with the C port of the four-way valve (2).

6. A self-cascade heat pump cycle as recited in claim 5, further comprising:

a controller, a first temperature sensor and a second temperature sensor;

the first temperature sensor is arranged on the outer surface of the indoor heat exchanger (11), and the second temperature sensor is arranged on the outer surface of the outdoor heat exchanger (3);

the controller is respectively and electrically connected with the first temperature sensor, the second temperature sensor, the four-way valve (2) and the electric control valve;

the controller is used for controlling the four-way valve (2) to switch a connecting port based on a temperature signal of the first temperature sensor so as to switch a refrigerating mode and a heating mode;

the controller is used for controlling the switch of the electric control valve based on the temperature signal of the second temperature sensor so as to switch the defrosting pipeline of the outdoor heat exchanger (3).

7. An air conditioner, comprising:

a self-cascade heat pump cycle as in any one of claims 1-6.

8. A control method of a self-cascade heat pump cycle system, the self-cascade heat pump cycle system being as set forth in any one of claims 1 to 7, characterized in that,

acquiring the surface temperature of the indoor heat exchanger (11);

if the surface temperature of the indoor heat exchanger (11) is greater than a first preset value, starting a refrigeration mode;

and if the surface temperature of the indoor heat exchanger (11) is smaller than or equal to a first preset value, starting a heating mode.

9. The control method according to claim 8, characterized by comprising:

if the outdoor heat exchanger is in a heating mode, the surface temperature of the outdoor heat exchanger (3) is obtained;

if the surface temperature of the outdoor heat exchanger (3) is higher than the frosting temperature, a defrosting pipeline of the outdoor heat exchanger (3) is not started;

and if the surface temperature of the outdoor heat exchanger (3) is smaller than or equal to the frosting temperature, starting a defrosting pipeline of the outdoor heat exchanger (3) until the surface temperature of the outdoor heat exchanger (3) is larger than the frosting temperature, and closing the defrosting pipeline of the outdoor heat exchanger (3).

10. A control method according to claim 9, characterized in that said closing the defrost line of the outdoor heat exchanger (3) until after the surface temperature of the outdoor heat exchanger (3) is greater than the frosting temperature comprises:

and when the surface temperature of the outdoor heat exchanger (3) is higher than the frosting temperature, starting timing, and closing the defrosting pipeline of the outdoor heat exchanger (3) after the preset time is reached.