CN107166809B

CN107166809B - Air source heat pump and control method thereof

Info

Publication number: CN107166809B
Application number: CN201710463354.3A
Authority: CN
Inventors: 刘雄; 王谦; 黄从新; 张俊; 惠芳芳; 郭�旗; 刘珂; 杨艳芳; 侯文生; 王玉琦
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-10-09
Filing date: 2017-06-12
Publication date: 2025-01-24
Anticipated expiration: 2037-06-12
Also published as: CN206905336U; CN107166809A

Abstract

The invention discloses an air source heat pump and a control method thereof, comprising a main compression mechanism, a heater, at least two first reversing devices, two first heat exchangers and two first throttling mechanisms, and also comprising a liquid return device, wherein the outlet end of the liquid return device is connected to the inlet end of the main compression mechanism through a first low-pressure gas pipe, the outlet end of the main compression mechanism is connected to a high-pressure liquid pipe in turn through a heater, and the inlet end of the liquid return device is connected to a pipeline between the outlet end of the main compression mechanism and the heater through a high-pressure gas pipe; one end of the first throttling mechanism is connected to the high-pressure liquid pipe, and the other end of the first throttling mechanism is connected to the reversing node of the first reversing device through a first heat exchanger, the low-pressure node of the first reversing device is connected to the first low-pressure gas pipe, and the high-pressure node of the first reversing device is connected to the high-pressure gas pipe. When operating in winter, heat absorption from outdoor air can be realized for defrosting, continuous heat supply can be achieved during defrosting, and gas-liquid shock can be avoided.

Description

Air source heat pump and control method thereof

Technical Field

The invention relates to an air source heat pump and a control method thereof, belonging to the technical field of refrigeration.

Background

With the increasing of economic development and environmental protection requirements, the use of air source heat pumps is more and more common, but the heat supply quantity of the existing single air source heat pump is smaller, when the air source heat pump is used as a heat source of a central heating system, the heat supply area of the single air source heat pump is not large, when the air source heat pump needs to bear a large central heating area, a mode of connecting a plurality of air source heat pumps in parallel and simultaneously supplying heat through a water system is not beneficial to the operation regulation of the central heating system, the freezing prevention of the water system of the air source heat pump is also not beneficial, the hydraulic balance of the water system also can lead the manufacturing cost of the whole heat pump system to be increased, in addition, the existing air source heat pump generally adopts a reverse circulation hot air defrosting mode for defrosting, the problem that the cold and hot air quantity are mutually restricted is known, the energy consumption caused by defrosting in the whole heating season is quite large, and meanwhile, the air source heat pump can not normally supply heat when defrosting, and other commonly used defrosting modes, such as hot air bypass defrosting, and heat supply usually also need to be stopped when defrosting.

The invention patent with the application number 200610037147.3 disclosed by the Shanghai Geli electric apparatus, inc. at 2/27/2008 provides a heat recovery multi-split air conditioner, and the system compositions of the heat recovery multi-split air conditioner are shown in figure 15.

As can be seen from fig. 15, when the heat exchanger 2 is a hot water heater and the heat exchanger 3 is an outdoor air-refrigerant heat exchanger, a large-scale air source heat pump system is formed, in which a plurality of heat exchangers 3 are connected in parallel between the high-pressure air pipe 5, the medium-pressure liquid pipe 6 and the low-pressure air pipe 7, and each heat exchanger 3 can independently and respectively play the roles of an evaporator and a condenser, so that the advantage brought by the heating in winter is that when one heat exchanger 3 needs defrosting, the heat exchanger 3 can be converted from the evaporator to the condenser by switching the four-way valve 4, and the other heat exchangers 3 continue to play the role of the evaporator, absorb heat from the outdoor air and continue to supply heat to the user through the heat exchanger 2, thereby achieving the purposes of defrosting by absorbing frost from the outdoor air and continuously supplying heat, and overcoming the defects of the reverse circulation hot gas defrosting mode.

However, the system shown in fig. 15 has the problems that when the system works in the actual use process, during the heating working condition in winter, the exhaust gas of the compressor 1 directly enters the heat exchanger 2 to produce heating hot water for a user, the refrigerant gas in the high-pressure air pipe 5 is almost in a stagnation state, the refrigerant gas can be condensed into liquid due to long-time heat dissipation to the outside air of the outer surface of the high-pressure air pipe 5, and if the refrigerant liquid cannot be timely discharged through the capillary tube 8, the refrigerant liquid is mixed with the overheat vapor of the refrigerant during defrosting and is gasified again, so that the pressure working condition in the high-pressure air pipe 5 is changed suddenly, and the four-way valve 4 is easy to damage. In addition, in the system start-up stage shown in fig. 15, since the high-pressure air pipe 5 is in a cold state and has a low temperature, and at this time, the exhaust pressure and the temperature of the compressor 1 are low, so that a large amount of refrigerant liquid is generated in the high-pressure air pipe 5 in the start-up stage, and since the capillary tube 8 has a large resistance in order to reduce the loss of air leakage in the normal operation stage, it is impossible to timely drain the refrigerant liquid generated in the heating pipe in the start-up stage, and therefore, the gas-liquid impact is generated in the high-pressure air pipe 5 in the start-up stage, which is more likely to damage the four-way valve 4 and destroy the normal operation of the system.

Disclosure of Invention

The invention aims to provide an air source heat pump which can absorb heat from outdoor air to defrost, can continuously supply heat during defrosting and can avoid gas-liquid impact and a control method thereof.

In order to overcome the problems of the prior art, the technical scheme for solving the technical problems is as follows:

1. The air source heat pump is characterized by further comprising a liquid return device, wherein the outlet end of the liquid return device is connected with the inlet end of the main compression mechanism through a first low-pressure gas pipe, the outlet end of the main compression mechanism is connected with a high-pressure liquid pipe sequentially through the inlet end of the heater and the outlet end of the heater, and the inlet end of the liquid return device is connected with a pipeline between the outlet end of the main compression mechanism and the inlet end of the heater through a high-pressure gas pipe;

One end of the first throttling mechanism is connected with the high-pressure liquid pipe, the other end of the first throttling mechanism is connected with a reversing node of the first reversing device through a first heat exchanger, a low-pressure node of the first reversing device is connected with the first low-pressure gas pipe, and a high-pressure node of the first reversing device is connected with the high-pressure gas pipe.

2. The air source heat pump is characterized by further comprising an auxiliary compression mechanism, an inlet end of the auxiliary compression mechanism is connected with the inlet end of the main compression mechanism through a first low-pressure gas pipe, an outlet end of the main compression mechanism is connected with a high-pressure liquid pipe sequentially through the inlet end of the heater and the outlet end of the heater, an outlet end of the auxiliary compression mechanism is connected with a high-pressure node of the first reversing device through a high-pressure gas pipe, one of the first reversing device, one of the first heat exchangers and one of the first throttling mechanisms form a group of outdoor heat exchange units, one end of the first throttling mechanism is connected with the high-pressure liquid pipe, the other end of the first throttling mechanism is connected with the reversing node of the first reversing device through a first heat exchanger, and the low-pressure node of the first reversing device is connected with the first low-pressure gas pipe.

3. The air source heat pump comprises a main compression mechanism, a heater, at least one first reversing device, one first heat exchanger and one first throttling mechanism, and is characterized by further comprising an auxiliary compression mechanism, at least one second reversing device, one second heat exchanger and one second throttling mechanism, wherein the first reversing device, the first heat exchanger and the first throttling mechanism form a group of outdoor heat exchange units;

The inlet end of the auxiliary compression mechanism is connected with the low-pressure node of the second reversing device through a second low-pressure gas pipe, the outlet end of the auxiliary compression mechanism is connected with a pipeline between the outlet end of the main compression mechanism and the inlet end of the heater through a high-pressure gas pipe, the other end of the first throttling mechanism is connected with the reversing node of the first reversing device through a first heat exchanger, and the high-pressure node of the first reversing device is connected with the high-pressure gas pipe;

the other end of the second throttling mechanism is connected with a reversing node of the second reversing device through a second heat exchanger, and a high-pressure node of the second reversing device is connected with a high-pressure gas pipe.

4. The air source heat pump is characterized by further comprising an auxiliary compression mechanism and a liquid return device, wherein the first four-way valve, the first heat exchanger, the first throttle mechanism and the first one-way valve form a group of outdoor heat exchange units, an inlet end of the auxiliary compression mechanism is connected with an inlet end of the main compression mechanism through a first low-pressure gas pipe, an outlet end of the main compression mechanism is connected with one end of the first throttle mechanism through an inlet end of the heater, an outlet end of the heater and a high-pressure liquid pipe in sequence, an outlet end of the auxiliary compression mechanism is connected with a high-pressure node of the first four-way valve through a high-pressure gas pipe, the other end of the first throttle mechanism is connected with a first reversing node of the first four-way valve through a first heat exchanger, a low-pressure node of the first four-way valve is connected with a first low-pressure node of the first valve, and the outlet end of the main compression mechanism is connected with the first reversing valve through a high-pressure gas pipe and the first reversing valve through a high-pressure gas pipe.

5. The air source heat pump comprises a main compression mechanism, a heater, at least one first four-way valve, a first heat exchanger, a first throttling mechanism and a first one-way valve, at least one second four-way valve, a second heat exchanger, a second throttling mechanism and a second one-way valve, and is characterized by further comprising an auxiliary compression mechanism and a liquid return device, wherein the first four-way valve, the first heat exchanger, the first throttling mechanism and the first one-way valve form a group of outdoor heat exchange units, and the second four-way valve, the second heat exchanger, the second throttling mechanism and the second one-way valve also form a group of outdoor heat exchange units;

The inlet end of the auxiliary compression mechanism is connected with the low-pressure node of the second four-way valve through a second low-pressure gas pipe, the outlet end of the auxiliary compression mechanism is connected with a pipeline between the outlet end of the main compression mechanism and the inlet end of the heater through a high-pressure gas pipe, the high-pressure node of the second four-way valve is connected with the high-pressure gas pipe through a high-pressure gas pipe, the third reversing node of the second four-way valve is connected with the other end of the second throttling mechanism through a second heat exchanger, the fourth reversing node of the second four-way valve is sequentially connected with the first low-pressure gas pipe or the second low-pressure gas pipe through a second one-way valve inlet end, a second one-way valve outlet end, a high-pressure exhaust pipe and a liquid return device, the high-pressure node of the second four-way valve is sequentially connected with the high-pressure node of the first four-way valve through a second heat exchanger and the high-pressure node of the four-way valve, and the high-pressure node of the fourth reversing node of the second four-way valve is sequentially connected with the high-pressure node of the first four-way valve through the high-pressure gas pipe or the high-pressure node of the first four-way valve.

6. The air source heat pump comprises a main compression mechanism, a heater, at least two first four-way valves, two first heat exchangers, two first throttling mechanisms and two first one-way valves, and is characterized by further comprising a liquid return device;

The first four-way valve, the first heat exchanger, the first throttling mechanism and the first one-way valve form a group of outdoor heat exchange units;

the inlet end of the main compression mechanism is sequentially connected with a first reversing node of the first four-way valve through a first low-pressure gas pipe, an outlet end of the liquid return device, an inlet end of the liquid return device, a high-pressure exhaust pipe, an outlet end of the first one-way valve and an inlet end of the first one-way valve, and the second reversing node of the first four-way valve is sequentially connected with the outlet end of the main compression mechanism through a first heat exchanger, a first throttling mechanism, a high-pressure liquid pipe, an outlet end of the heater and an inlet end of the heater;

The high-pressure node of the first four-way valve is connected with a pipeline between the outlet end of the main compression mechanism and the inlet end of the heater through a high-pressure gas pipe, and the low-pressure node of the first four-way valve is connected with the first low-pressure gas pipe.

7. The air source heat pump comprises a main compression mechanism, a heater, at least two first four-way valves, two first heat exchangers, two first throttling mechanisms and two first one-way valves, and is characterized by further comprising a liquid return device;

The inlet end of the main compression mechanism is connected with the outlet end of the main compression mechanism sequentially through a first low-pressure gas pipe, the outlet end of the liquid return device, the inlet end of the liquid return device and a high-pressure gas pipe;

The high-pressure node of the first four-way valve is connected with the high-pressure gas pipe, the first reversing node of the first four-way valve is connected with the second reversing node of the first four-way valve sequentially through a first heat exchanger, a first throttling mechanism, a high-pressure liquid pipe, a heater outlet end, a heater inlet end, a high-pressure exhaust pipe, a first one-way valve outlet end and a first one-way valve inlet end, and the low-pressure node of the first four-way valve is connected with the first low-pressure gas pipe.

8. The air source heat pump comprises a main compression mechanism, a heater, at least two first reversing devices, two first heat exchangers and two first throttling mechanisms, and is characterized by further comprising a defrosting control valve, wherein one first reversing device, one first heat exchanger and one first throttling mechanism form a group of outdoor heat exchange units;

the main compression mechanism outlet end is connected with the reversing node of the first reversing device sequentially through the heater inlet end, the heater outlet end, the high-pressure liquid pipe, the first throttling mechanism and the first heat exchanger, the main compression mechanism inlet end is connected with the low-pressure node of the first reversing device through the first low-pressure gas pipe, and the high-pressure node of the first reversing device is connected with a pipeline between the main compression mechanism outlet end and the heater inlet end sequentially through the high-pressure gas pipe and the defrosting control valve.

9. The control method of the air source heat pump comprises a main compression mechanism, a heater and a defrosting control valve, wherein at least two first reversing devices, two first heat exchangers and two first throttling mechanisms;

The connection relation of the components is that the outlet end of the main compression mechanism is connected with the reversing node of the first reversing device sequentially through the inlet end of the heater, the outlet end of the heater, the high-pressure liquid pipe, the first throttling mechanism and the first heat exchanger, the inlet end of the main compression mechanism is connected with the low-pressure node of the first reversing device through the first low-pressure gas pipe, the high-pressure node of the first reversing device is connected with the pipeline between the outlet end of the main compression mechanism and the inlet end of the heater sequentially through the high-pressure gas pipe and the defrosting control valve, and the air source heat pump is characterized in that the control method is as follows:

1) When the controller detects that the air source heat pump does not need defrosting, the defrosting control valve is in a closed state, and a reversing node of the first reversing device is communicated with a low-pressure node;

2) When the controller detects that any one of the first heat exchangers needs to be defrosted, the reversing node of the first reversing device matched with the first heat exchanger needing to be defrosted is communicated with the high-pressure node, and meanwhile, the reversing node of the first reversing device matched with the first heat exchanger needing to be defrosted and the low-pressure node are in a closed state;

3) When the controller detects that the defrosting of the first heat exchanger requiring defrosting is finished, the defrosting control valve is closed, so that the reversing node of the first reversing device matched with the first heat exchanger requiring defrosting is communicated with the low-pressure node.

10. The air source heat pump comprises a main compression mechanism, a heater, at least two first four-way valves, two first heat exchangers, two first throttling mechanisms and two first one-way valves, and is characterized by further comprising an auxiliary compression mechanism, wherein the heater comprises a first heating coil and a second heating coil;

The inlet end of the auxiliary compression mechanism is connected with the inlet end of the main compression mechanism through a first low-pressure gas pipe, and the outlet end of the main compression mechanism is connected with one end of the first throttling mechanism sequentially through the inlet end of the heater, the first heating coil pipe of the heater, the outlet end of the heater and the high-pressure liquid pipe;

the outlet end of the auxiliary compression mechanism is connected with a high-pressure node of the first four-way valve through a high-pressure gas pipe;

the other end of the first throttling mechanism is connected with a first reversing node of the first four-way valve through a first heat exchanger, a low-pressure node of the first four-way valve is connected with the first low-pressure gas pipe, and a second reversing node of the first four-way valve is connected with the high-pressure liquid pipe through a first one-way valve inlet end, a first one-way valve outlet end, a high-pressure exhaust pipe, a heater inlet end, a second heating coil of the heater and a heater outlet end in sequence.

11. The air source heat pump comprises a main compression mechanism, a heater, at least one first four-way valve, a first heat exchanger, a first throttling mechanism and a first one-way valve, at least one second four-way valve, a second heat exchanger, a second throttling mechanism and a second one-way valve, and is characterized by further comprising an auxiliary compression mechanism, wherein the heater comprises a first heating coil and a second heating coil;

the first four-way valve, the first heat exchanger, the first throttling mechanism and the first one-way valve form a group of outdoor heat exchange units; one of the second four-way valve, one of the second heat exchangers, one of the second throttling mechanism and one of the second one-way valves also form a group of outdoor heat exchange units;

The inlet end of the main compression mechanism is connected with a low-pressure node of the first four-way valve through a first low-pressure gas pipe, and the outlet end of the main compression mechanism is connected with one end of the first throttling mechanism and one end of the second throttling mechanism respectively through the inlet end of the heater, the first heating coil pipe of the heater, the outlet end of the heater and the high-pressure liquid pipe in sequence;

The inlet end of the auxiliary compression mechanism is connected with a low-pressure node of the second four-way valve through a second low-pressure gas pipe, the outlet end of the auxiliary compression mechanism is connected with a pipeline between the outlet end of the main compression mechanism and the inlet end of the heater through a high-pressure gas pipe, the high-pressure node of the second four-way valve is connected with the high-pressure gas pipe, the third reversing node of the second four-way valve is connected with the other end of the second throttling mechanism through a second heat exchanger, and the fourth reversing node of the second four-way valve is connected with the high-pressure liquid pipe sequentially through the inlet end of the second one-way valve, the outlet end of the second one-way valve, the high-pressure exhaust pipe, the inlet end of the heater, the second heating coil of the heater and the outlet end of the heater;

The high-pressure node of the first four-way valve is connected with the high-pressure gas pipe or a pipeline between the high-pressure node of the second four-way valve and the high-pressure gas pipe, the first reversing node of the first four-way valve is connected with the other end of the first throttling mechanism through a first heat exchanger, and the second reversing node of the first four-way valve is connected with the high-pressure exhaust pipe sequentially through the inlet end of the first one-way valve and the outlet end of the first one-way valve.

12. The air source heat pump comprises a main compression mechanism and a heater, and is characterized in that the heater of the air source heat pump comprises a first heating coil and a second heating coil, one of the first four-way valve, the first heat exchanger, the first throttling mechanism and the first one-way valve form a group of outdoor heat exchange units, the inlet end of the main compression mechanism is connected with a low-pressure node of the first four-way valve through a first low-pressure gas pipe, the first reversing node of the first four-way valve is sequentially connected with the outlet end of the main compression mechanism through a first heat exchanger, a first throttling mechanism, a high-pressure liquid pipe, a heater outlet end, a first heating coil and a heater inlet end of the heater, the second reversing node of the first four-way valve is sequentially connected with the inlet end of the first one-way valve, the outlet end of the first one-way valve, a high-pressure exhaust pipe, the heater inlet end and the heater inlet end of the heater, and the high-pressure pipe, and the first reversing node of the heater inlet end of the heater is sequentially connected with the high-pressure coil and the high-pressure coil.

Compared with the prior art, the invention has the beneficial effects that:

1. when in operation, the outdoor air can absorb heat and defrost, and when in defrosting, the outdoor air can continuously supply heat;

2. Gas-liquid impact can be avoided;

3. The structure is simple;

4. The invention is suitable for industrial and civil heat pump equipment, and is especially suitable for occasions with air as a low-temperature heat source.

Drawings

FIG. 1 is a schematic view of the structure of embodiment 1 of the present invention;

FIG. 2 is a schematic structural view of embodiment 2 of the present invention;

FIG. 3 is a schematic structural diagram of a variation of embodiment 2 of the present invention;

FIG. 4 is a schematic view showing the structure of embodiment 3 of the present invention;

FIG. 5 is a schematic view showing the structure of embodiment 4 of the present invention;

FIG. 6 is a schematic view showing the structure of embodiment 5 of the present invention;

FIG. 7 is a schematic view showing the structure of embodiment 6 of the present invention;

FIG. 8 is a schematic view of the structure of embodiment 7 of the present invention;

FIG. 9 is a schematic view showing the structure of embodiment 8 of the present invention;

fig. 10 is a schematic structural view of a first reversing device according to an embodiment of the present invention;

fig. 11 is a schematic structural view of a second reversing device according to an embodiment of the present invention;

FIG. 12 is a schematic view showing the structure of embodiment 9 of the present invention;

FIG. 13 is a schematic view showing the structure of embodiment 10 of the present invention;

FIG. 14 is a schematic view showing the structure of embodiment 11 of the present invention;

fig. 15 is a schematic view of a prior art structure.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Example 1

As shown in fig. 1, the present embodiment is a large-sized air source heat pump capable of absorbing heat from the outdoor air to defrost, continuously supplying heat during defrosting, and avoiding gas-liquid impact. The air source heat pump is used for occasions with heat supply requirements all year round. The whole equipment comprises a main compression mechanism 1, a heater 2, at least two first reversing devices 40, two first heat exchangers 3 and two first throttling mechanisms 4, and also comprises a liquid return device 30. The liquid return device 30 consists of a first electromagnetic valve 32, a first capillary tube 31 and a temperature sensor 34, wherein the connection relationship of the first electromagnetic valve 32 and the temperature sensor 34 in the system is that the inlet end of the first electromagnetic valve 32 is connected with the high-pressure gas pipe 5, the outlet end of the first electromagnetic valve 32 is connected with the first low-pressure gas pipe 6 through the first capillary tube 31, and the temperature sensor 34 is arranged on the pipeline at the inlet end or the pipeline at the outlet end of the first electromagnetic valve 32. The inlet end of the first electromagnetic valve 32 is the inlet end of the liquid return device 30, and the connecting end of the first capillary tube 31 and the first low-pressure gas tube 6 is the outlet end of the liquid return device 30.

In the system shown in fig. 1, one of the first reversing devices 40, one of the first heat exchangers 3 and one of the first throttle mechanisms 4 constitute a set of outdoor heat exchange units. The first reversing device 40 is an electromagnetic three-way valve 20, and the connection relation of the electromagnetic three-way valve 20 in the system is that a normally open node of the electromagnetic three-way valve 20 is connected with a reversing node C of the first reversing device 40, any one reversing node of the two reversing nodes of the electromagnetic three-way valve 20 is connected with a high-pressure node A of the first reversing device 40, and the other reversing node of the electromagnetic three-way valve 20 is connected with a low-pressure node B of the first reversing device 40. The first throttle mechanism 4 is an electronic expansion valve.

The air source heat pump can realize the heat supply function and the winter heat supply and defrosting function in the whole year operation process. When the defrosting device works, under the heating and defrosting functions in winter, when any one of the first heat exchangers 3 needs defrosting, the first heat exchanger 3 can be converted into a condenser through switching of the first reversing device 40 matched with the first heat exchanger, and the defrosting is performed by utilizing the heat absorbed by the other first heat exchangers 3 without defrosting from the outdoor air. The heater 2 acts as a condenser throughout the year to provide heat to the user. The workflow under each function is as follows.

(1) Heating function

In operation, the first throttle mechanism 4 is operating normally. The flow path between the high voltage node a and the commutation node C of the first commutation means 40 is closed and the flow path between the low voltage node B and the commutation node C of the first commutation means 40 is opened.

The working flow is that the refrigerant is divided into two paths after being discharged from the outlet end of the main compression mechanism 1, and most of the refrigerant sequentially passes through the inlet end of the heater 2, the outlet end of the heater 2, the high-pressure liquid pipe 7, the first throttling mechanism 4, the first heat exchanger 3, the reversing node C of the first reversing device 40, the low-pressure node B of the first reversing device 40 and the first low-pressure gas pipe 6, enters the inlet end of the main compression mechanism 1, and the other small part enters the high-pressure gas pipe 5 and stagnates in the high-pressure gas pipe 5;

in operation, due to heat dissipation from the surface of the high-pressure gas pipe 5, a part of the refrigerant stagnating therein is condensed into refrigerant liquids, and when the temperature sensor 34 detects that the refrigerant liquids have a certain supercooling degree relative to the refrigerant saturation temperature corresponding to the exhaust pressure of the main compression mechanism 1, the controller gives out an instruction, opens the first electromagnetic valve 32, so that the refrigerant liquids accumulated in the high-pressure gas pipe 5 are discharged into the first low-pressure gas pipe 6 through the first capillary tube 31, and after being mixed with the first path, enter the main compression mechanism 1 to be compressed again, thus completing one cycle.

(2) Winter heating and defrosting function

Under this function, the scheme shown in fig. 1, wherein one group of first heat exchangers 3 which do not need to be defrosted still is an evaporator for absorbing heat from outdoor air, the other group of first heat exchangers 3 which do need to be defrosted is converted into a condenser for defrosting, the heater 2 still supplies heat to a user, that is to say, the heat absorbed by the group of first heat exchangers 3 is used for the heat supply of the user together with the work consumed by the compressor and the defrosting of the other group of first heat exchangers 3, so that the defrosting method has no mutual offset problem of cold and heat compared with the reverse circulation hot air defrosting, the essence of the defrosting method is to absorb frost from the outdoor air, when a large-scale air source heat pump has a plurality of groups of first heat exchangers 3, the defrosting of one group of first heat exchangers 3 has small influence on the heat supply quantity of the air source heat pump, and particularly in practical engineering, the air source heat pump is selected according to the most adverse working conditions, and generally works under partial load, therefore, the output capacity of the air source heat pump is usually regulated to meet the requirement of the user for heating.

In operation, the first reversing device 40 associated with the group of first heat exchangers 3 to be defrosted needs to be switched, and the communication mode after the first reversing device 40 is switched is that the communication channel between the high-pressure node A and the reversing node C of the first reversing device 40 is opened, and the communication channel between the low-pressure node B and the reversing node C of the first reversing device 40 is closed. When defrosting, the first throttling mechanism 4 matched with the group of first heat exchangers 3 needing defrosting controls the refrigerant gas quantity used for defrosting by setting the opening degree.

The working flow is that the refrigerant is divided into two paths after being discharged from the outlet end of the main compression mechanism 1, the first path passes through the inlet end of the heater 2 and the outlet end of the heater 2 and then enters the high-pressure liquid pipe 7, the second path passes through the high-pressure gas pipe 5, the high-pressure node A of the first reversing device 40 matched with the first heat exchanger 3 needing defrosting, the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 needing defrosting, the first throttling mechanism 4 matched with the first heat exchanger 3 needing defrosting and also enters the high-pressure liquid pipe 7, and after being mixed in the high-pressure liquid pipe 7, the two paths of refrigerant sequentially pass through the first throttling mechanism 4 matched with the first heat exchanger 3 needing defrosting, the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 needing defrosting, the low-pressure node B of the first reversing device 40 matched with the first heat exchanger 3 needing defrosting, and the first low-pressure gas pipe 6, and then returns to the inlet end of the main compression mechanism 1. At this time, the first solenoid valve 32 should be in a closed state. In practical applications, the first reversing device 40 may be the following scheme (as shown in fig. 10) besides the electromagnetic three-way valve 20:

1) The first reversing device 40 is formed by a second electromagnetic valve 21 and a third electromagnetic valve 22, and is connected in a manner that one end of the second electromagnetic valve 21 is connected with a high-pressure node A of the first reversing device 40, the other end of the second electromagnetic valve 21 is connected with a low-pressure node B of the first reversing device 40 through the third electromagnetic valve 22, and a reversing node C of the first reversing device 40 is connected with a pipeline between the second electromagnetic valve 21 and the third electromagnetic valve 22.

2) The first reversing device 40 is formed by a first four-way valve 50, the second reversing node 54 of the first four-way valve 50 is always in a cut-off state, and the connection mode is that the high-pressure node 51 of the first four-way valve 50 is connected with the high-pressure node A of the first reversing device 40, the low-pressure node 53 of the first four-way valve 50 is connected with the low-pressure node B of the first reversing device 40, and the first reversing node 52 of the first four-way valve 50 is connected with the reversing node C of the first reversing device 40.

3) First reversing device 40 is formed by a first four-way valve 50 and a second capillary tube 35. The connection mode is that the high-pressure node 51 of the first four-way valve 50 is connected with the high-pressure node A of the first reversing device 40, the low-pressure node 53 of the first four-way valve 50 is connected with the low-pressure node B of the first reversing device 40, the first reversing node 52 of the first four-way valve 50 is connected with the reversing node C of the first reversing device 40, and the second reversing node 54 of the first four-way valve 50 is connected with a pipeline between the low-pressure node 53 of the first four-way valve 50 and the low-pressure node B of the first reversing device 40 through the second capillary tube 35.

Example 2

As shown in fig. 2, this embodiment is also a large-sized air source heat pump capable of absorbing heat from the outdoor air to defrost, continuously supplying heat during defrosting, and avoiding gas-liquid impact. The entire plant comprises the main compression mechanism 1, the auxiliary compression mechanism 8, the heater 2, at least two first reversing devices 40, two first heat exchangers 3 and two first throttle mechanisms 4.

In the system shown in fig. 2, one of the first reversing devices 40, one of the first heat exchangers 3 and one of the first throttle mechanisms 4 constitute a set of outdoor heat exchange units. The first reversing device 40 is composed of the second solenoid valve 21 and the third solenoid valve 22, and their connection relationship in the system is as described in embodiment 1. The first throttle mechanism 4 is an electronic expansion valve.

(1) Heating function

In operation, the first throttle mechanism 4 is operating normally. The second solenoid valve 21 is closed or opened and the third solenoid valve 22 is opened. The main compression mechanism 1 is normally operated and the auxiliary compression mechanism 8 is not operated.

The working flow is that after being discharged from the outlet end of the main compression mechanism 1, the refrigerant sequentially passes through the inlet end of the heater 2, the outlet end of the heater 2, the high-pressure liquid pipe 7, the first throttle mechanism 4, the first heat exchanger 3, the third electromagnetic valve 22 and the first low-pressure gas pipe 6, and enters the inlet end of the main compression mechanism 1 to complete one cycle.

(2) Winter heating and defrosting function

Under this function, the main compression mechanism 1 and the auxiliary compression mechanism 8 are operated simultaneously, the scheme shown in fig. 2 is that one group of first heat exchangers 3 without defrosting still is an evaporator for absorbing heat from the outdoor air, the other group of first heat exchangers 3 with defrosting needs are converted into condensers for defrosting, the heater 2 still supplies heat to the user, that is to say, one group of first heat exchangers 3 is utilized for absorbing heat from the outdoor air, and the absorbed heat and the work consumed by the compressor are used for the heat supply of the user and the defrosting of the other group of first heat exchangers 3 together. In operation, the second electromagnetic valve 21 matched with the group of first heat exchangers 3 needing defrosting is opened, the third electromagnetic valve 22 is closed, and the first throttle mechanism 4 matched with the group of first heat exchangers 3 needing defrosting controls the exhaust amount of the auxiliary compression mechanism 8 for defrosting by setting the opening degree. While the second solenoid valve 21, which is associated with the first heat exchanger 3, which does not require defrosting, is closed and the third solenoid valve 22 is still open.

The working flow is that the low-pressure refrigerant gas in a first low-pressure gas pipe 6 is divided into two paths during working, the first path enters a main compression mechanism 1 to be compressed, the refrigerant is discharged from the outlet end of the main compression mechanism 1 and then enters a high-pressure liquid pipe 7 through the inlet end of a heater 2 and the outlet end of the heater 2, the second path enters an auxiliary compression mechanism 8 to be compressed, the refrigerant is discharged from the outlet end of the auxiliary compression mechanism 8 and then sequentially passes through a high-pressure gas pipe 5, a second electromagnetic valve 21 matched with the first heat exchanger 3 requiring defrosting, the first heat exchanger 3 requiring defrosting and a first throttle mechanism 4 matched with the first heat exchanger 3 requiring defrosting, and also enters the high-pressure liquid pipe 7, and after the two paths of refrigerant liquid are mixed in the high-pressure liquid pipe 7, the refrigerant sequentially passes through the first throttle mechanism 4 matched with the first heat exchanger 3 requiring no defrosting, the first heat exchanger 3 requiring no defrosting and a third electromagnetic valve 22 matched with the first heat exchanger 3 requiring no defrosting, and returns to the first low-pressure gas pipe 6 to complete one-time circulation.

The scheme shown in fig. 3 is a variation of the scheme shown in fig. 2. In the scheme shown in fig. 3, the outlet end of the auxiliary compression mechanism 8 is connected with the high-pressure node a of the first reversing device 40 not only through the high-pressure gas pipe 5, but also through the pipeline between the high-pressure gas pipe 5 and the main compression mechanism 1 and the heater 2, so that the auxiliary compression mechanism 8 can also work normally when the heat pump works under the heat supply function, and the defect that the auxiliary compression mechanism 8 cannot work normally when the scheme shown in fig. 2 works under the heat supply function is overcome.

Example 3

As shown in fig. 4, this embodiment is also a large-sized air source heat pump capable of absorbing heat from the outdoor air to defrost, continuously supplying heat during defrosting, and avoiding gas-liquid impact. The whole device comprises a main compression mechanism 1, an auxiliary compression mechanism 8, a heater 2, at least one first reversing device 40, one first heat exchanger 3 and one first throttle mechanism 4, at least one second reversing device 41, one second heat exchanger 9 and one second throttle mechanism 10.

In the system shown in fig. 4, one of the first reversing devices 40, one of the first heat exchangers 3 and one of the first throttle mechanisms 4 constitute a set of outdoor heat exchange units. The first reversing device 40 is composed of the second solenoid valve 21 and the third solenoid valve 22, and their connection relationship in the system is as described in embodiment 1. The first throttle mechanism 4 and the second throttle mechanism 10 are electronic expansion valves. Likewise, in the system shown in fig. 4, one of the second reversing devices 41, one of the second heat exchangers 9 and one of the second throttle mechanisms 10 also constitute a set of outdoor heat exchange units. The second reversing device 41 is formed by a fourth electromagnetic valve 23 and a fifth electromagnetic valve 24, and the connection relation of the fourth electromagnetic valve 23 and the fifth electromagnetic valve 24 in the system is that one end of the fourth electromagnetic valve 23 is connected with a high-pressure node A of the second reversing device 41, the other end of the fourth electromagnetic valve 23 is connected with a low-pressure node B of the second reversing device 41 through the fifth electromagnetic valve 24, and a reversing node C of the second reversing device 41 is connected with a pipeline between the fourth electromagnetic valve 23 and the fifth electromagnetic valve 24. The second reversing device 41 may be constituted by the fourth solenoid valve 23 and the fifth solenoid valve 24, and may have the following configurations:

1) The second reversing device 41 may also be formed by an electromagnetic three-way valve 20, and the connection mode is that a normally open node of the electromagnetic three-way valve 20 is connected with a reversing node C of the second reversing device 41, any one reversing node of the two reversing nodes of the electromagnetic three-way valve 20 is connected with a high-pressure node A of the second reversing device 41, and the other reversing node of the electromagnetic three-way valve 20 is connected with a low-pressure node B of the second reversing device 41.

2) As shown in fig. 11, the second reversing device 41 is formed by a second four-way valve 80, the fourth reversing node 84 of the second four-way valve 80 is always in a cut-off state, and the connection mode is that the high-pressure node 81 of the second four-way valve 80 is connected with the high-pressure node a of the second reversing device 41, the low-pressure node 83 of the second four-way valve 80 is connected with the low-pressure node B of the second reversing device 41, and the third reversing node 82 of the second four-way valve 80 is connected with the reversing node C of the second reversing device 41.

3) As shown in fig. 11, the second reversing device 41 is constituted by a second four-way valve 80 and a third capillary tube 36. The connection mode is that the high-pressure node 81 of the second four-way valve 80 is connected with the high-pressure node A of the second reversing device 41, the low-pressure node 83 of the second four-way valve 80 is connected with the low-pressure node B of the second reversing device 41, the third reversing node 82 of the second four-way valve 80 is connected with the reversing node C of the second reversing device 41, and the fourth reversing node 84 of the second four-way valve 80 is connected with a pipeline between the low-pressure node 83 of the second four-way valve 80 and the low-pressure node B of the second reversing device 41 through the third capillary tube 36.

The air source heat pump can also realize the heat supply function and the winter heat supply and defrosting function in the whole year operation process. When the defrosting device works, the first heat exchanger 3 and the second heat exchanger 9 are used as evaporators under the heat supply function, absorb heat from the environment, and when the first heat exchanger 3 needs defrosting in winter under the heat supply and defrosting function, the first heat exchanger is converted into a condenser through the switching of the first reversing device 40 matched with the first heat exchanger, the defrosting is performed by utilizing the heat absorbed by the second heat exchanger 9 without defrosting from the outdoor air, and similarly, when the second heat exchanger 9 needs defrosting, the second heat exchanger 9 is converted into a condenser through the switching of the second reversing device 41 matched with the second heat exchanger, and the heat absorbed by the first heat exchanger 3 without defrosting from the outdoor air is utilized for defrosting. The heater 2 acts as a condenser throughout the year to provide heat to the user. The workflow under each function is as follows.

(1) Heating function

In operation, both the first throttle mechanism 4 and the second throttle mechanism 10 are operating normally. The second and fourth solenoid valves 21, 23 are closed, and the third and fifth solenoid valves 22, 24 are opened. The main compression mechanism 1 and the auxiliary compression mechanism 8 both operate normally.

The working flow is that the refrigerant liquid from the outlet end of the heater 2 is divided into two paths after entering the high-pressure liquid pipe 7, the first path sequentially passes through the first throttling mechanism 4, the first heat exchanger 3, the reversing node C of the first reversing device 40, the third electromagnetic valve 22, the low-pressure node B of the first reversing device 40 and the first low-pressure gas pipe 6, enters the main compression mechanism 1 to be compressed and then is discharged into the outlet end pipeline of the main compression mechanism 1, the second path sequentially passes through the second throttling mechanism 10, the second heat exchanger 9, the reversing node C of the second reversing device 41, the fifth electromagnetic valve 24 and the low-pressure node B of the second reversing device 41 and the second low-pressure gas pipe 12, enters the auxiliary compression mechanism 8 to be compressed and then is discharged into the outlet end pipeline of the main compression mechanism 1 through the high-pressure gas pipe 5, and the two paths of refrigerant are mixed at the outlet end pipeline of the main compression mechanism 1 and then enter the high-pressure liquid pipe 7 through the heater 2 to complete one cycle.

(2) Winter heating and defrosting function

Under the function, the method is divided into two operation conditions, wherein one is that when the first heat exchanger 3 needs defrosting, the second heat exchanger 9 does not need defrosting, and works normally, and absorbs heat from the outdoor air and is respectively used for heating and defrosting of the first heat exchanger 3, and the other is that when the second heat exchanger 9 needs defrosting, the first heat exchanger 3 does not need defrosting, works normally, absorbs heat from the outdoor air and is respectively used for heating and defrosting of the second heat exchanger 9. The operation thereof is as follows.

1) When the first heat exchanger 3 needs defrosting, the second heat exchanger 9 works normally

At this time, the main compression mechanism 1 is not operated, the auxiliary compression mechanism 8 is normally operated, the second and fifth solenoid valves 21, 24 are opened, the third and fourth solenoid valves 22, 23 are closed, the first throttle mechanism 4 controls the amount of refrigerant gas entering the first heat exchanger 3 for defrosting by setting the opening degree, and the second throttle mechanism 10 is normally operated. The working flow is that the refrigerant is discharged from the outlet end of the auxiliary compression mechanism 8 and enters the high-pressure gas pipe 5 to be divided into two paths, the first path sequentially passes through the high-pressure node A of the first reversing device 40, the second electromagnetic valve 21, the reversing node C of the first reversing device 40, the first heat exchanger 3 and the first throttling mechanism 4 and enters the high-pressure liquid pipe 7, the second path sequentially passes through the inlet end of the heater 2 and the outlet end of the heater 2 and also enters the high-pressure liquid pipe 7, and after the high-pressure liquid pipe 7 is mixed, the two paths of refrigerant sequentially pass through the second throttling mechanism 10, the second heat exchanger 9, the reversing node C of the second reversing device 41, the fifth electromagnetic valve 24, the low-pressure node B of the second reversing device 41 and the second low-pressure gas pipe 12 and enter the auxiliary compression mechanism 8 to be compressed, so as to finish one cycle.

2) When the second heat exchanger 9 needs defrosting, the first heat exchanger works normally

At this time, the main compression mechanism 1 is normally operated, the auxiliary compression mechanism 8 is not operated, the second and fifth solenoid valves 21, 24 are closed, the third and fourth solenoid valves 22, 23 are opened, the second throttle mechanism 10 controls the amount of refrigerant gas entering the second heat exchanger 9 for defrosting by setting the opening degree, and the first throttle mechanism 4 is normally operated. The working flow is that the refrigerant is divided into two paths after being discharged from the outlet end of the main compression mechanism 1, the first path sequentially passes through the high-pressure gas pipe 5, the high-pressure node A of the second reversing device 41, the fourth electromagnetic valve 23, the reversing node C of the second reversing device 41, the second heat exchanger 9 and the second throttling mechanism 10 and enters the high-pressure liquid pipe 7, the second path sequentially passes through the inlet end of the heater 2 and the outlet end of the heater 2 and also enters the high-pressure liquid pipe 7, and after the high-pressure liquid pipe 7 is mixed, the two paths of refrigerant sequentially passes through the first throttling mechanism 4, the first heat exchanger 3, the reversing node C of the first reversing device 40, the third electromagnetic valve 22, the low-pressure node B of the first reversing device 40 and the first low-pressure gas pipe 6, and then enters the main compression mechanism 1 to be compressed, so that one cycle is completed.

Example 4

As shown in fig. 5, this embodiment is also a large-sized air source heat pump capable of absorbing heat from the outdoor air to defrost, continuously supplying heat during defrosting, and avoiding gas-liquid impact. The whole equipment comprises a main compression mechanism 1, an auxiliary compression mechanism 8, a heater 2, at least two first four-way valves 50, two first heat exchangers 3, two first throttling mechanisms 4 and two first check valves 71, and a liquid return device 30. The liquid return device 30 consists of a first capillary tube 31, and the connection relation of the liquid return device in the system is that the inlet end of the first capillary tube 31 is connected with the high-pressure exhaust pipe 11, and the outlet end of the first capillary tube 31 is connected with the first low-pressure gas pipe 6.

In the system shown in fig. 5, one of the first four-way valves 50, one of the first heat exchangers 3, one of the first throttle mechanisms 4, and one of the first check valves 71 constitute a group of outdoor heat exchange units. The first throttle mechanism 4 is an electronic expansion valve.

The air source heat pump can realize the heat supply function and the winter heat supply and defrosting function in the annual operation process. When the first heat exchanger 3 is used as an evaporator to absorb heat from the environment in the heat supply function, and when any one of the first heat exchangers 3 needs defrosting in winter in the heat supply and defrosting function, the first heat exchanger 3 can be converted into a condenser through switching of the first four-way valve 50 matched with the first heat exchanger, and the heat absorbed by the other first heat exchangers 3 without defrosting is utilized to defrost the outdoor air and simultaneously supply heat. The heater 2 acts as a condenser throughout the year to provide heat to the user. The workflow under each function is as follows.

(1) Heating function

During operation, the first throttle mechanism 4 and the main compression mechanism 1 are both normally operated, and the auxiliary compression mechanism 8 is not operated. The first reversing node 52 of the first four-way valve 50 communicates with the low-pressure node 53 of the first four-way valve 50, and the second reversing node 54 of the first four-way valve 50 communicates with the high-pressure node 51 of the first four-way valve 50. The working flow under the function is that after being discharged from the outlet end of the main compression mechanism 1, the refrigerant sequentially passes through the inlet end of the heater 2, the outlet end of the heater 2, the high-pressure liquid pipe 7, the first throttle mechanism 4, the first heat exchanger 3, the first reversing node 52 of the first four-way valve 50, the low-pressure node 53 of the first four-way valve 50 and the first low-pressure gas pipe 6, and enters the inlet end of the main compression mechanism 1 to be compressed again, thus completing one cycle.

(2) Winter heating and defrosting function

Under this function, the main compression mechanism 1 and the auxiliary compression mechanism 8 both operate normally. One group of the first heat exchangers 3 which do not need to be defrosted still absorbs heat from the outdoor air by the evaporator, the other group of the first heat exchangers 3 which do not need to be defrosted is converted into a condenser for defrosting, the heater 2 still supplies heat to the user, that is, the heat absorbed by the group of the first heat exchangers 3 absorbs heat from the outdoor air and the work consumed by the compressor is used for the heat supply of the user and the defrosting of the other group of the first heat exchangers 3 together.

In operation, the first four-way valve 50 matched with the group of first heat exchangers 3 needing defrosting needs to be switched, and the communication mode after the switching of the first four-way valve 50 is that the high-pressure node 51 of the first four-way valve 50 is communicated with the first reversing node 52, and the low-pressure node 53 of the first four-way valve 50 is communicated with the second reversing node 54. When defrosting, the first throttling mechanism 4 matched with the group of first heat exchangers 3 needing defrosting controls the exhaust amount of the auxiliary compression mechanism 8 for defrosting by setting the opening degree.

The working flow is that the low-pressure refrigerant gas in the first low-pressure gas pipe 6 is divided into two paths when in work; the first path enters the main compression mechanism 1 to be compressed, and after being discharged from the outlet end of the main compression mechanism 1, the refrigerant sequentially passes through the inlet end of the heater 2 and the outlet end of the heater 2 to enter the high-pressure liquid pipe 7; the second path enters the auxiliary compression mechanism 8 to be compressed, and after the refrigerant is discharged from the outlet end of the auxiliary compression mechanism 8, the refrigerant enters the high-pressure gas pipe 5 and is divided into a third path which occupies most part and a fourth path which occupies small part; the third path sequentially passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 needing defrosting, the first reversing node 52 of the first four-way valve 50 matched with the first heat exchanger 3 needing defrosting, the first heat exchanger 3 needing defrosting and the first throttling mechanism 4 matched with the first heat exchanger 3 needing defrosting and also enters the high-pressure liquid pipe 7, after being mixed with the high-pressure liquid pipe 7, the first path and the third path of refrigerant sequentially pass through the first throttling mechanism 4 matched with the first heat exchanger 3 not needing defrosting, the first reversing node 52 of the first four-way valve 50 matched with the first heat exchanger 3 not needing defrosting, the low-pressure node 53 of the first four-way valve 50 matched with the first heat exchanger 3 not needing defrosting and return to the first low-pressure gas pipe 6, the fourth path of refrigerant sequentially passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 not needing defrosting, the first reversing node 54 of the first four-way valve 50 matched with the first heat exchanger 3 not needing defrosting, the first capillary tube 31 not needing defrosting and the first reversing valve 11, and the two paths of refrigerants respectively enter the main compression mechanism 1 and the auxiliary compression mechanism 8 to be compressed after being mixed in the first low-pressure gas pipe 6, so that one cycle is completed.

The liquid return device 30 may be composed of the first capillary 31, and the following scheme is also possible:

1) As shown in fig. 1, it is composed of a first solenoid valve 32, a first capillary tube 31 and a temperature sensor 34, and is connected in the same manner as in embodiment 1. A temperature sensor 34 may also be provided on the conduit between the outlet end of the first solenoid valve 32 and the first capillary tube 31.

2) As shown in FIG. 7, the device consists of a first electromagnetic valve 32, a first capillary tube 31, a liquid accumulator 33 and a temperature sensor 34, wherein the inlet end of the first electromagnetic valve 32 is connected with a high-pressure gas pipe 5 through the outlet end of the liquid accumulator 33 and the inlet end of the liquid accumulator 33 in sequence, the outlet end of the first electromagnetic valve 32 is connected with a first low-pressure gas pipe 6 through the first capillary tube 31, and the temperature sensor 34 is arranged on a pipeline between the outlet end of the liquid accumulator 33 and the inlet end of the first electromagnetic valve 32 or a pipeline between the outlet end of the first electromagnetic valve 32 and the first capillary tube 31. The inlet end of the liquid accumulator 33 is the inlet end of the liquid return device 30.

In practical applications, the scheme shown in fig. 5 may be further improved. In a further development, the outlet end of the auxiliary compression mechanism 8 is not only connected to the high-pressure node 51 of the first four-way valve 50 via the high-pressure gas pipe 5, but also connected to the conduit between the outlet end of the main compression mechanism 1 and the inlet end of the heater 2 via the high-pressure gas pipe 5, so that the auxiliary compression mechanism 8 can also work normally when the heat pump works under the heating function, and the defect that the auxiliary compression mechanism 8 cannot work normally when the scheme shown in fig. 5 works under the heating function is overcome.

Example 5

As shown in fig. 6, this embodiment is also a large-sized air source heat pump capable of absorbing heat from the outdoor air to defrost, continuously supplying heat during defrosting, and avoiding gas-liquid impact. The whole apparatus comprises a main compression mechanism 1, an auxiliary compression mechanism 8, a heater 2, at least one first four-way valve 50, one first heat exchanger 3, one first throttle mechanism 4 and one first one-way valve 71, at least one second four-way valve 80, one second heat exchanger 9, one second throttle mechanism 10 and one second one-way valve 72.

In the system shown in fig. 6, one of the first four-way valves 50, one of the first heat exchangers 3, one of the first throttle mechanisms 4, and one of the first check valves 71 constitute a group of outdoor heat exchange units. The first throttle mechanism 4 and the second throttle mechanism 10 are electronic expansion valves. Similarly, in the system shown in fig. 6, one of the second four-way valves 80, one of the second heat exchangers 9, one of the second throttle mechanisms 10, and one of the second check valves 72 also constitute a set of outdoor heat exchange units.

The air source heat pump can also realize the heat supply function and the winter heat supply and defrosting function in the whole year operation process. When the defrosting device works, the first heat exchanger 3 and the second heat exchanger 9 are used as evaporators under the heat supply function, heat is absorbed from the environment, when the first heat exchanger 3 needs defrosting in winter under the heat supply and defrosting function, the first heat exchanger 3 is converted into a condenser through switching of the first four-way valve 50 matched with the first heat exchanger, the defrosting is performed by using the heat absorbed from the outdoor air by the second heat exchanger 9 without defrosting, and similarly, when the second heat exchanger 9 needs defrosting, the first heat exchanger 3 without defrosting is converted into a condenser through switching of the second four-way valve 80 matched with the second heat exchanger, and the heat absorbed from the outdoor air by the first heat exchanger 3 without defrosting is used for defrosting. The heater 2 acts as a condenser throughout the year to provide heat to the user. The workflow under each function is as follows.

(1) Heating function

In operation, the first throttle mechanism 4 and the second throttle mechanism 10 are both operated normally, the main compression mechanism 1 and the auxiliary compression mechanism 8 are also operated normally, the high-pressure node 51 of the first four-way valve 50 is communicated with the second reversing node 54 of the first four-way valve 50, the low-pressure node 53 of the first four-way valve 50 is communicated with the first reversing node 52 of the first four-way valve 50, the high-pressure node 81 of the second four-way valve 80 is communicated with the fourth reversing node 84 of the second four-way valve 80, and the low-pressure node 83 of the second four-way valve 80 is communicated with the third reversing node 82 of the second four-way valve 80.

The working flow is that the refrigerant liquid from the outlet end of the heater 2 is divided into two paths after entering the high-pressure liquid pipe 7; the first path of refrigerant sequentially passes through the first throttling mechanism 4, the first heat exchanger 3, the first reversing node 52 of the first four-way valve 50 and the low-pressure node 53 of the first four-way valve 50 and enters the first low-pressure gas pipe 6; the second path of refrigerant sequentially passes through the second throttling mechanism 10, the second heat exchanger 9, the third reversing node 82 of the second four-way valve 80, the low-pressure node 83 of the second four-way valve 80 and the second low-pressure gas pipe 12, enters the auxiliary compression mechanism 8 to be compressed and then enters the high-pressure gas pipe 5 to be divided into a third path which occupies the majority and a fourth path which occupies the small part and a fifth path, the third path of refrigerant enters an outlet end pipeline of the main compression mechanism 1 through the high-pressure gas pipe 5, the fourth path of refrigerant sequentially passes through the high-pressure node 51 of the first four-way valve 50, the second reversing node 54 of the first four-way valve 50 and the first one-way valve 71 and enters the high-pressure exhaust pipe 11, the fifth path of refrigerant sequentially passes through the high-pressure node 81 of the second four-way valve 80, the fourth reversing node 84 of the second four-way valve 80 and the second one-way valve 72 and also enters the high-pressure exhaust pipe 11, the fourth path and the fifth path of refrigerant also enter the first low-pressure gas pipe 6 after being mixed with the high-pressure exhaust pipe 11, the fourth path of refrigerant also enters the first low-pressure gas pipe 6 through the liquid return device 30 and the first path of refrigerant enters the main compression mechanism 1 at the outlet end 1 after being mixed with the first path of refrigerant and the first path of refrigerant enters the main compression mechanism 1 at the outlet end 2, and is sequentially heated at the inlet end 1, and is discharged into the main compression mechanism 1, and then enters the main compression mechanism 1, after being sequentially, and is heated at the inlet end of the high-pressure compression mechanism 1.

(2) Winter heating and defrosting function

Under this function, it is divided into two operating conditions, one is that the second heat exchanger 9 does not need defrosting when the first heat exchanger 3 needs defrosting, but works normally, absorbs heat from the outdoor air and is used for heating and defrosting the first heat exchanger 3 respectively, and the other is that the first heat exchanger 3 does not need defrosting when the second heat exchanger 9 needs defrosting, but works normally, absorbs heat from the outdoor air and is used for heating and defrosting the second heat exchanger 9 respectively. The operation thereof is as follows.

At this time, the main compression mechanism 1 is not operated, the auxiliary compression mechanism 8 is normally operated, the first four-way valve 50 is required to be reversed, the second four-way valve 80 is kept unchanged, the communication state is the same as that under the heat supply function, the reversed communication state of the first four-way valve 50 is that the high-pressure node 51 of the first four-way valve 50 is communicated with the first reversing node 52 of the first four-way valve 50, the low-pressure node 53 of the first four-way valve 50 is communicated with the second reversing node 54 of the first four-way valve 50, the first throttling mechanism 4 controls the amount of refrigerant gas entering the first heat exchanger 3 for defrosting by setting the opening degree, and the second throttling mechanism 10 is normally operated.

The working flow is that after being discharged from the outlet end of the auxiliary compression mechanism 8, the refrigerant enters the high-pressure gas pipe 5 to be divided into two paths, the first path sequentially passes through the high-pressure node 51 of the first four-way valve 50, the first reversing node 52 of the first four-way valve 50, the first heat exchanger 3 and the first throttling mechanism 4, enters the high-pressure liquid pipe 7, the second path also enters the high-pressure liquid pipe 7 through the heater 2, and after the high-pressure liquid pipe 7 is mixed, the two paths of refrigerant sequentially pass through the second throttling mechanism 10, the second heat exchanger 9, the third reversing node 82 of the second four-way valve 80, the low-pressure node 83 of the second four-way valve 80 and the second low-pressure gas pipe 12, and enter the auxiliary compression mechanism 8 to be compressed, so as to finish one cycle.

2) When the second heat exchanger 9 needs defrosting, the first heat exchanger 3 works normally

At this time, the main compression mechanism 1 is normally operated, the auxiliary compression mechanism 8 is not operated, the first four-way valve 50 does not need to be reversed, the communication state is the same as that under the heat supply function, the second four-way valve 80 needs to be reversed, the reversed communication state of the second four-way valve 80 is that the high-pressure node 81 of the second four-way valve 80 is communicated with the third reversing node 82 of the second four-way valve 80, the low-pressure node 83 of the second four-way valve 80 is communicated with the fourth reversing node 84 of the second four-way valve 80, the second throttling mechanism 10 controls the amount of refrigerant gas entering the second heat exchanger 9 for defrosting by setting the opening, and the first throttling mechanism 4 is normally operated.

The working flow is that the refrigerant is divided into three paths after being discharged from the outlet end of the main compression mechanism 1, the first path sequentially passes through the high-pressure gas pipe 5, the high-pressure node 81 of the second four-way valve 80, the third reversing node 82 of the second four-way valve 80, the second heat exchanger 9 and the second throttling mechanism 10, and enters the high-pressure liquid pipe 7, the second path also enters the high-pressure liquid pipe 7 through the heater 2, the first path and the second path of refrigerant are mixed in the high-pressure liquid pipe 7, then sequentially passes through the first throttling mechanism 4, the first heat exchanger 3, the first reversing node 52 of the first four-way valve 50, the low-pressure node 53 of the first four-way valve 50 and enters the first low-pressure gas pipe 6, and the third path of refrigerant sequentially passes through the high-pressure gas pipe 5, the high-pressure node 51 of the first four-way valve 50, the second reversing node 54 of the first one-way valve 71, the high-pressure exhaust pipe 11 and the liquid return device 30, and also enters the first low-pressure gas pipe 6, and the two paths of refrigerant are mixed in the first low-pressure gas pipe 6, and then enter the main compression mechanism 1, and are compressed again.

Example 6

As shown in fig. 7, this embodiment is also a large-sized air source heat pump capable of absorbing heat from the outdoor air to defrost, continuously supplying heat during defrosting, and avoiding gas-liquid impact. The whole equipment comprises a main compression mechanism 1, a heater 2, at least two first four-way valves 50, two first heat exchangers 3, two first throttle mechanisms 4, two first check valves 71 and a liquid return device 30. The liquid return device 30 is composed of a first solenoid valve 32, a first capillary tube 31, a liquid trap 33 and a temperature sensor 34. Their connection in the system is described in detail in example 4.

In the system shown in fig. 7, one of the first four-way valves 50, one of the first heat exchangers 3, one of the first throttle mechanisms 4, and one of the first check valves 71 constitute a group of outdoor heat exchange units. The first throttle mechanism 4 is an electronic expansion valve.

The air source heat pump can realize the heat supply function and the winter heat supply and defrosting function in the annual operation process. When the first heat exchanger 3 is used as an evaporator under the heat supply function and absorbs heat from the environment, and under the heat supply and defrosting function in winter, when any one of the first heat exchangers 3 needs defrosting, the first heat exchanger 3 can be converted into a condenser through switching of the first four-way valve 50 matched with the first heat exchanger, and the heat absorbed by the other first heat exchangers 3 without defrosting is utilized for defrosting and simultaneously supplying heat. The heater 2 acts as a condenser throughout the year to provide heat to the user. The workflow under each function is as follows.

(1) Heating function

In operation, the first throttle mechanism 4 and the main compression mechanism 1 are both operating normally. The first reversing node 52 of the first four-way valve 50 communicates with the low-pressure node 53 of the first four-way valve 50, and the second reversing node 54 of the first four-way valve 50 communicates with the high-pressure node 51 of the first four-way valve 50.

The working flow under the function is that the refrigerant is divided into two paths after being discharged from the outlet end of the main compression mechanism 1, the first path sequentially passes through the inlet end of the heater 2, the outlet end of the heater 2, the high-pressure liquid pipe 7, the first throttle mechanism 4, the first heat exchanger 3, the first reversing node 52 of the first four-way valve 50 and the low-pressure node 53 of the first four-way valve 50, enters the first low-pressure gas pipe 6, the second path sequentially passes through the high-pressure gas pipe 5, the high-pressure node 51 of the first four-way valve 50, the second reversing node 54 of the first four-way valve 50, the first one-way valve 71, the high-pressure exhaust pipe 11 and the liquid return device 30, and also enters the first low-pressure gas pipe 6, and after the two paths are mixed in the first low-pressure gas pipe 6, the two paths enter the inlet end of the main compression mechanism 1 and are compressed again, so that one cycle is completed.

(2) Winter heating and defrosting function

Under this function, the main compression mechanism 1 operates normally. One group of the first heat exchangers 3 which do not need to be defrosted still is an evaporator for absorbing heat from the outdoor air, the other group of the first heat exchangers 3 which do not need to be defrosted is converted into a condenser for defrosting, the heater 2 still supplies heat to the user, that is, the heat absorbed by the group of the first heat exchangers 3 is used for the heat supply of the user together with the work consumed by the compressor and the defrosting of the other group of the first heat exchangers 3.

In operation, the first four-way valve 50 matched with the group of first heat exchangers 3 needing defrosting needs to be switched, and the communication mode after the switching of the first four-way valve 50 is that the high-pressure node 51 of the first four-way valve 50 is communicated with the first reversing node 52, and the low-pressure node 53 of the first four-way valve 50 is communicated with the second reversing node 54. When defrosting, the first throttling mechanism 4 matched with the group of first heat exchangers 3 needing defrosting controls the refrigerant gas quantity used for defrosting by setting the opening degree.

The working flow is that the refrigerant is divided into three paths after being discharged from the outlet end of the main compression mechanism 1; the first path enters a high-pressure liquid pipe 7 through the heater 2; the second path enters the high-pressure gas pipe 5 and is divided into a third path and a fourth path; the third path sequentially passes through a high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 needing defrosting, a first reversing node 52 of the first four-way valve 50 matched with the first heat exchanger 3 needing defrosting, the first heat exchanger 3 needing defrosting and the first throttling mechanism 4 matched with the first heat exchanger 3 needing defrosting and also enters the high-pressure liquid pipe 7, after the high-pressure liquid pipe 7 is mixed, the first path and the third path of refrigerant sequentially passes through the first throttling mechanism 4 matched with the first heat exchanger 3 not needing defrosting, a first reversing node 52 of the first four-way valve 50 matched with the first heat exchanger 3 not needing defrosting and a low-pressure node 53 of the first four-way valve 50 matched with the first heat exchanger 3 not needing defrosting and returns to the first low-pressure gas pipe 6, the fourth path of refrigerant sequentially passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 not needing defrosting, the first reversing valve 54 matched with the first heat exchanger 3 not needing defrosting and the first reversing valve 6, and then enters the first reversing valve 1 again, and the first reversing valve 1 is compressed again, and the first reversing valve is compressed, and the first reversing valve is cooled, and the first refrigerant and the first and the third refrigerant and the third and the third and the and the and 3.

The liquid return device 30 may also be composed of a first capillary tube 31, or a first solenoid valve 32, the first capillary tube 31 and a temperature sensor 34.

Example 7

As shown in fig. 8, this embodiment is also a large-sized air source heat pump capable of absorbing heat from the outdoor air to defrost, continuously supplying heat during defrosting, and avoiding gas-liquid impact. The whole equipment comprises a main compression mechanism 1, a heater 2, at least two first four-way valves 50, two first heat exchangers 3, two first throttle mechanisms 4, two first check valves 71 and a liquid return device 30. The liquid return device 30 is composed of a first solenoid valve 32, a first capillary tube 31, a liquid trap 33 and a temperature sensor 34. Their connection in the system is described in detail in example 4.

In the system shown in fig. 8, one of the first four-way valves 50, one of the first heat exchangers 3, one of the first throttle mechanisms 4, and one of the first check valves 71 constitute a group of outdoor heat exchange units. The first throttle mechanism 4 is an electronic expansion valve.

(1) Heating function

In operation, the first throttle mechanism 4 and the main compression mechanism 1 are both operating normally. The first reversing node 52 of the first four-way valve 50 communicates with the low-pressure node 53 of the first four-way valve 50, and the second reversing node 54 of the first four-way valve 50 communicates with the high-pressure node 51 of the first four-way valve 50. The working flow under the function is that after being discharged from the outlet end of the main compression mechanism 1, the refrigerant enters the high-pressure gas pipe 5 and is divided into two paths, the first path sequentially passes through the high-pressure gas pipe 5 and the liquid return device 30 and enters the first low-pressure gas pipe 6, the second path sequentially passes through the high-pressure node 51 of the first four-way valve 50, the second reversing node 54 of the first four-way valve 50, the inlet end of the first one-way valve 71, the outlet end of the first one-way valve 71, the high-pressure exhaust pipe 11, the inlet end of the heater 2, the outlet end of the heater 2, the high-pressure liquid pipe 7, the first throttling mechanism 4, the first heat exchanger 3, the first reversing node 52 of the first four-way valve 50 and the low-pressure node 53 of the first four-way valve 50, and also enters the first low-pressure gas pipe 6, and after being mixed in the first low-pressure gas pipe 6, the two paths enter the inlet end of the main compression mechanism 1 and are compressed again, so that one cycle is completed.

(2) Winter heating and defrosting function

Under this function, the main compression mechanism 1 operates normally. One group of the first heat exchangers 3 which do not need to be defrosted normally work and still the evaporator absorbs heat from the outdoor air, the other group of the first heat exchangers 3 which do not need to be defrosted is converted into a condenser to defrost, and the heater 2 still supplies heat to a user.

The working flow is that the refrigerant is discharged from the outlet end of the main compression mechanism 1 and then enters the high-pressure gas pipe 5 to be divided into three paths; the first path sequentially passes through the high-pressure gas pipe 5 and the liquid return device 30 and enters the first low-pressure gas pipe 6; the second path sequentially passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 without defrosting, the second reversing node 54 of the first four-way valve 50 matched with the first heat exchanger 3 without defrosting, the first one-way valve 71 matched with the first heat exchanger 3 without defrosting, the high-pressure exhaust pipe 11 and the heater 2, and enters the high-pressure liquid pipe 7, the third path sequentially passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 without defrosting, the first reversing node 52 of the first four-way valve 50 matched with the first heat exchanger 3 with defrosting, the first throttling mechanism 4 matched with the first heat exchanger 3 with defrosting, and then sequentially passes through the first throttling mechanism 4 matched with the first heat exchanger 3 without defrosting, the first four-way valve 50 matched with the first heat exchanger 3 without defrosting, and then enters the low-pressure gas circulation mechanism 6 again after being mixed with the high-pressure liquid pipe 7, and then enters the first low-pressure circulation valve 6 again after the first path is mixed with the first refrigerant, and the first path is subjected to the first low-pressure circulation valve 6, and the first refrigerant is subjected to the first compression stage and the first circulation stage.

The liquid return device 30 may be composed of a first capillary tube 31, or may be composed of a first solenoid valve 32, the first capillary tube 31, a liquid accumulator 33, and a temperature sensor 34.

Example 8

As shown in fig. 9, this embodiment is also a large-sized air source heat pump capable of absorbing heat from the outdoor air to defrost, continuously supplying heat during defrosting, and avoiding gas-liquid impact. The whole device comprises a main compression mechanism 1, a heater 2, at least two first reversing devices 40, two first heat exchangers 3 and two first throttle mechanisms 4, and a defrost control valve 90. In the system shown in fig. 9, one of the first reversing devices 40, one of the first heat exchangers 3 and one of the first throttle mechanisms 4 constitute a set of outdoor heat exchange units. The first reversing device 40 is composed of the second solenoid valve 21 and the third solenoid valve 22, and their connection relationship in the system is as described in embodiment 1. The first throttle mechanism 4 is an electronic expansion valve, and the defrost control valve 90 is a solenoid valve.

(1) Heating function

In operation, the main compression mechanism 1 and the first throttle mechanism 4 are both operating normally, the defrost control valve 90 is closed, the second solenoid valve 21 is closed or opened, and the third solenoid valve 22 is opened. The working flow is that after being discharged from the outlet end of the main compression mechanism 1, the refrigerant sequentially passes through the inlet end of the heater 2, the outlet end of the heater 2, the high-pressure liquid pipe 7, the first throttle mechanism 4, the first heat exchanger 3, the reversing node C of the first reversing device 40, the third electromagnetic valve 22, the low-pressure node B of the first reversing device 40 and the first low-pressure gas pipe 6, and enters the inlet end of the main compression mechanism 1 to be compressed again, so as to finish one cycle.

(2) Winter heating and defrosting function

Under this function, the scheme shown in fig. 9, in which one group of first heat exchangers 3 which do not need defrosting still works as an evaporator to absorb heat from the outdoor air, the other group of first heat exchangers 3 which do need defrosting are converted into condensers to defrost, the heater 2 still supplies heat to the user, that is, the heat absorbed by the group of first heat exchangers 3 absorbs heat from the outdoor air and the work consumed by the compressor is used together for the heat supply of the user and the defrosting of the other group of first heat exchangers 3.

In operation, the first reversing device 40 associated with the group of first heat exchangers 3 to be defrosted needs to be switched, i.e. the second solenoid valve 21 associated with the first heat exchanger 3 to be defrosted is opened and the third solenoid valve 22 associated with the first heat exchanger 3 to be defrosted is closed. When defrosting, the first throttling mechanism 4 matched with the group of first heat exchangers 3 needing defrosting controls the refrigerant gas quantity used for defrosting by setting the opening degree. The first reversing device 40 associated with the first heat exchanger 3 that does not require defrosting does not require switching and the defrost control valve 90 is opened.

The working flow is that the refrigerant is divided into two paths after being discharged from the outlet end of the main compression mechanism 1, the first path passes through the heater 2 and then enters the high-pressure liquid pipe 7, the second path sequentially passes through the defrosting control valve 90, the high-pressure gas pipe 5, the high-pressure node A of the first reversing device 40 matched with the first heat exchanger 3 needing defrosting, the second electromagnetic valve 21 of the first reversing device 40 matched with the first heat exchanger 3 needing defrosting, the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 needing defrosting, the first heat exchanger 3 needing defrosting and the first throttling mechanism 4 matched with the first heat exchanger 3 needing defrosting, and then enters the high-pressure liquid pipe 7, and after being mixed in the high-pressure liquid pipe 7, the two paths of refrigerant sequentially pass through the first throttling mechanism 4 matched with the first heat exchanger 3 needing defrosting, the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 needing defrosting, the first reversing mechanism 4 needing defrosting, the first throttling mechanism 4 matched with the first heat exchanger 3 needing defrosting, and the first reversing mechanism C of the first reversing mechanism 1 needing defrosting, and then enter the main compression mechanism 1 again, and the two paths of refrigerant liquid are compressed to be completed.

The first reversing device 40 may be composed of the second solenoid valve 21 and the third solenoid valve 22, and may also be 1) composed of the solenoid three-way valve 20, and the connection relationship in the system is described in embodiment 1.

In the working process of the scheme shown in fig. 9 of this embodiment, the control method of the air source heat pump is as follows:

1) When the controller detects that the air source heat pump does not need defrosting, i.e. in normal operation, the defrosting control valve 90 is in a closed state, and the reversing node C of the first reversing device 40 is communicated with the low-pressure node B, in the scheme shown in fig. 9, the third electromagnetic valve 22 is opened, and the second electromagnetic valve 21 can be closed or opened.

2) When the controller detects that any one of the first heat exchangers 3 needs to be defrosted, the channel between the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 needing to be defrosted and the high-pressure node A is communicated, and meanwhile, the channel between the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 needing to be defrosted and the low-pressure node B is closed (namely, in the scheme shown in fig. 9, the second electromagnetic valve 21 is opened and the third electromagnetic valve 22 is closed), the defrosting control valve 90 is opened, the first throttling mechanism 4 matched with the first heat exchanger 3 needing to be defrosted controls the refrigerant gas amount for defrosting by setting the opening degree, and the channel between the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 needing not to be defrosted and the high-pressure node A is closed, and meanwhile, the channel between the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 needing not to be defrosted and the low-pressure node B is in an open state (namely, in the scheme shown in fig. 9, the second electromagnetic valve 21 is closed and the third electromagnetic valve 22 is opened.

3) When the controller detects that the defrosting of the first heat exchanger 3 requiring defrosting is finished, the defrosting control valve 90 is closed, so that the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 requiring defrosting is communicated with the low-pressure node B, in the scheme shown in fig. 9, the third electromagnetic valve 22 is opened, and the second electromagnetic valve 21 can be in a closed state or an open state.

Example 9

As shown in fig. 12, this embodiment is also a large-scale air source heat pump capable of absorbing heat from outdoor air to defrost, continuously supplying heat during defrosting, and avoiding gas-liquid impact, and is an improvement of the scheme shown in fig. 5 of embodiment 4. In the scheme shown in fig. 5, there is a principle leakage through the liquid return device 30 during normal operation, that is, when the auxiliary compression mechanism 8 is operating normally, a small portion of high-pressure exhaust gas of the compression mechanism will leak into the first low-pressure gas pipe 6 through the first capillary tube 31 of the liquid return device 30, and meanwhile, in the scheme shown in fig. 5, there is a defect that the auxiliary compression mechanism 8 cannot operate normally under the heating function, while the scheme shown in fig. 12 of this embodiment can overcome the above-mentioned defect of the scheme shown in fig. 5.

The solution shown in fig. 12 differs from the solution shown in fig. 5 in that in the solution shown in fig. 12, there are no liquid return device 30, two sets of refrigerant heating coils, namely, a first heating coil 101 and a second heating coil 102, are connected in parallel inside the heater 2, and the connection relationship of the heater 2 in the system is that one end of the first heating coil 101 of the heater 2 is connected with the outlet end of the main compression mechanism 1, the other end of the first heating coil 101 of the heater 2 is connected with the high-pressure liquid pipe 7, one end of the second heating coil 102 of the heater 2 is connected with the outlet end of the first check valve 71 through the high-pressure exhaust pipe 11, and the other end of the second heating coil 102 of the heater 2 is also connected with the high-pressure liquid pipe 7. The air source heat pump can realize the heat supply function and the winter heat supply and defrosting function in the whole year operation process. The workflow under each function is as follows.

(1) Heating function

In operation, the first throttle mechanism 4, the main compression mechanism 1, and the auxiliary compression mechanism 8 all operate normally. The first reversing node 52 of the first four-way valve 50 communicates with the low-pressure node 53 of the first four-way valve 50, and the second reversing node 54 of the first four-way valve 50 communicates with the high-pressure node 51 of the first four-way valve 50.

The working flow under the function is that part of low-pressure refrigerant gas from a first low-pressure gas pipe 6 is compressed by a main compression mechanism 1 and then discharged from an outlet end of the main compression mechanism, the low-pressure refrigerant gas sequentially passes through an inlet end of a heater 2, a first heating coil 101 of the heater 2 and an outlet end of the heater 2 and enters a high-pressure liquid pipe 7, the other part of low-pressure refrigerant gas from the first low-pressure gas pipe 6 is compressed by an auxiliary compression mechanism 8 and then discharged from an outlet end of the auxiliary compression mechanism, the low-pressure refrigerant gas sequentially passes through the high-pressure gas pipe 5, a high-pressure node 51 of a first four-way valve 50, a second reversing node 54 of the first four-way valve 50, an inlet end of a first one-way valve 71, an outlet end of the first one-way valve 71, a high-pressure exhaust pipe 11, an inlet end of the heater 2, a second heating coil 102 of the heater 2 and an outlet end of the heater 2, and then sequentially passes through a first four-way flow mechanism 4, a first heat exchanger 3, a first node 52 of the first four-way valve 50 and a first reversing node 53 of the first four-way valve 50 after being mixed in the high-pressure liquid pipe 7, the two-way refrigerant liquid sequentially passes through the first reversing mechanism 4, the first reversing node 53 of the first four-way valve 50 and enters the low-pressure mechanism 6, and is compressed again by the main compression mechanism 1, and is compressed again, and is once again compressed again, and the two-way refrigerant liquid is compressed by the main compression mechanism, and enters the main compression mechanism.

(2) Winter heating and defrosting function

The working flow is that the low-pressure refrigerant gas in the first low-pressure gas pipe 6 is divided into two paths when in work; the first path enters the main compression mechanism 1 to be compressed, and after being discharged from the outlet end of the main compression mechanism 1, the refrigerant sequentially passes through the inlet end of the heater 2, the first heating coil 101 of the heater 2 and the outlet end of the heater 2 to enter the high-pressure liquid pipe 7; the second path enters the auxiliary compression mechanism 8 to be compressed, the refrigerant is discharged from the outlet end of the auxiliary compression mechanism 8 and then enters the high-pressure liquid pipe 7, the refrigerant enters the high-pressure gas pipe 5 and is divided into a third path which occupies most part and a fourth path which occupies a small part, the third path sequentially passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 which needs to be defrosted, the first reversing node 52 of the first four-way valve 50 matched with the first heat exchanger 3 which needs to be defrosted, the first throttling mechanism 4 matched with the first heat exchanger 3 which needs to be defrosted and also enters the high-pressure liquid pipe 7, the fourth path refrigerant sequentially passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 which does not need to be defrosted, the second reversing node 54 of the first four-way valve 50 matched with the first heat exchanger 3 which does not need to be defrosted, the high-pressure exhaust pipe 11, the inlet end of the heater 2, the second heating coil 102, the outlet end of the heater 2, the outlet end of the high-pressure refrigerant 7 also enters the high-pressure liquid pipe 7, and the high-pressure refrigerant flows through the high-pressure node 51 of the first four-way valve 50 which does not need to be defrosted, and the first heat exchanger 3 which is matched with the first heat exchanger 3 which needs to be defrosted, and the high-pressure refrigerant flows through the high-pressure node 51 which is matched with the first four-pass through the first reversing valve 3 which does not need to be defrosted, and the first pathway is sequentially, the low-pressure node 53 of the first four-way valve 50 matched with the first heat exchanger 3 which does not need defrosting returns to the first low-pressure gas pipe 6, and enters the main compression mechanism 1 and the auxiliary compression mechanism 8 again to be compressed respectively, so that one cycle is completed.

The improvement of fig. 12 is that in order to avoid that the refrigerant liquid in the high-pressure liquid pipe 7 enters the high-pressure exhaust pipe 11 through the second heating coil 102 of the heater 2 under the heating and defrosting functions in winter, a third one-way valve 73 can be added between the second heating coil 102 and the high-pressure liquid pipe 7, and at this time, the third one-way valve 73 is connected in the system in such a way that the inlet end of the third one-way valve 73 is connected with the high-pressure exhaust pipe 11 through the second heating coil 102 of the heater 2, and the outlet end of the third one-way valve 73 is connected with the high-pressure liquid pipe 7.

Example 10

As shown in fig. 13, this embodiment is also a large-scale air source heat pump capable of absorbing heat from outdoor air to defrost, continuously supplying heat during defrosting, and avoiding gas-liquid impact, and is an improvement of the scheme shown in fig. 6 of embodiment 5. The solution shown in fig. 6 has a principle leakage through the liquid return device 30 during normal operation, i.e. during normal operation when the first solenoid valve 32 is opened, a small portion of the high pressure exhaust gas of the compression mechanism leaks into the first low pressure gas pipe 6 through the first capillary tube 31 of the liquid return device 30, whereas the solution shown in fig. 13 of this embodiment overcomes the above-mentioned drawbacks of the solution shown in fig. 6.

The solution shown in fig. 13 differs from the solution shown in fig. 6 in that in the solution shown in fig. 13, there are no liquid return device 30, two sets of refrigerant heating coils, namely, a first heating coil 101 and a second heating coil 102, are connected in parallel inside the heater 2, and the connection relationship of the heater 2 in the system is that one end of the first heating coil 101 of the heater 2 is connected with the outlet end of the main compression mechanism 1 and the high-pressure gas pipe 5, the other end of the first heating coil 101 of the heater 2 is connected with the high-pressure liquid pipe 7, and one end of the second heating coil 102 of the heater 2 is connected with the outlet end of the first check valve 71 through the high-pressure exhaust pipe 11, and the other end of the second heating coil 102 of the heater 2 is also connected with the high-pressure liquid pipe 7. The air source heat pump can realize the heat supply function and the winter heat supply and defrosting function in the annual operation process. The workflow under each function is as follows.

(1) Heating function

The working flow is that the refrigerant liquid entering the high-pressure liquid pipe 7 is divided into two paths; the first path of refrigerant sequentially passes through the first throttling mechanism 4, the first heat exchanger 3, the first reversing node 52 of the first four-way valve 50 and the low-pressure node 53 of the first four-way valve 50, enters the first low-pressure gas pipe 6, is compressed by the main compression mechanism 1, and then enters an outlet end pipeline of the main compression mechanism 1; the second path of refrigerant sequentially passes through the second throttling mechanism 10, the second heat exchanger 9, the third reversing node 82 of the second four-way valve 80, the low-pressure node 83 of the second four-way valve 80 and the second low-pressure gas pipe 12, and enters the auxiliary compression mechanism 8 to be compressed, and then enters the high-pressure gas pipe 5 to be divided into a third path which occupies the most part and a fourth path which occupies the small part and a fifth path, wherein the third path of refrigerant also enters the outlet end pipeline of the main compression mechanism 1 through the high-pressure gas pipe 5, is mixed with the first path of refrigerant in the outlet end pipeline of the main compression mechanism 1, then sequentially passes through the inlet end of the heater 2, the first heating coil 101 of the heater 2 and the outlet end of the heater 2, and enters the high-pressure liquid pipe 7, the fourth path of refrigerant sequentially passes through the high-pressure node 51 of the first four-way valve 50, the second reversing node 54 of the first one-way valve 71, the outlet end of the first one-way valve 71 and the high-pressure exhaust pipe 11, the fifth path of refrigerant sequentially passes through the high-pressure node 80, the fourth reversing node 80, the fourth heating coil 101 of the fourth path of refrigerant also passes through the second reversing valve 80, the fourth heating coil 11 and the second heating coil 2, the outlet end of the high-pressure coil 2, and the high-pressure liquid pipe 72 sequentially passes through the fourth reversing valve 80, the fourth heating coil 11, and the fourth heating coil 2 and the high-pressure coil 2, and the high-pressure refrigerant flows sequentially passes through the fourth reversing valve 71, and then sequentially passes through the high-pressure reversing valve 80 and the high-pressure valve 11, the refrigerant is mixed with the first and third paths in the high-pressure liquid pipe 7 and then divided into two paths, and thus one cycle is completed.

(2) Winter heating and defrosting function

The working flow of the high-pressure liquid tube heat pump comprises the following steps that after being discharged from the outlet end of an auxiliary compression mechanism 8, refrigerant enters a high-pressure gas tube 5 and is divided into three paths, the first path of refrigerant sequentially passes through a high-pressure node 51 of a first four-way valve 50, a first reversing node 52 of the first four-way valve 50, a first heat exchanger 3 and a first throttling mechanism 4 and enters a high-pressure liquid tube 7, the second path of refrigerant sequentially passes through the inlet end of the heater 2, a first heating coil 101 of the heater 2 and the outlet end of the heater 2 and also enters the high-pressure liquid tube 7, the third path of refrigerant sequentially passes through a high-pressure node 81 of a second four-way valve 80, a fourth reversing node 84 of the second four-way valve 80, an inlet end of a second one-way valve 72, an outlet end of the second one-way valve 72, a high-pressure exhaust pipe 11, an inlet end of the heater 2 and an outlet end of the heater 2, and also enters the high-pressure liquid tube 7, the three paths of refrigerant sequentially passes through the second throttling mechanism 10, the second heat exchanger 9, the third reversing node 82 of the second four-way valve 80 and the low-pressure gas tube 80 after being mixed, and then sequentially passes through the second reversing node 82 of the high-pressure liquid tube 7 and the second four-way refrigerant and is compressed by the auxiliary compression mechanism 8, and the auxiliary compression mechanism is completed.

The working flow of the refrigerant is divided into three paths after being discharged from the outlet end of the main compression mechanism 1, the first path sequentially passes through the high-pressure gas pipe 5, the high-pressure node 81 of the second four-way valve 80, the third reversing node 82 of the second four-way valve 80, the second heat exchanger 9 and the second throttling mechanism 10, and enters the high-pressure liquid pipe 7, the second path sequentially passes through the inlet end of the heater 2, the first heating coil 101 of the heater 2 and the outlet end of the heater 2 and also enters the high-pressure liquid pipe 7, the third path of refrigerant sequentially passes through the high-pressure gas pipe 5, the high-pressure node 51 of the first four-way valve 50, the second reversing node 54 of the first four-way valve 50, the inlet end of the first one-way valve 71, the outlet end of the first one-way valve 71, the high-pressure exhaust pipe 11, the inlet end of the heater 2, the second heating coil 102 of the heater 2 and the outlet end of the heater 2, and also enters the high-pressure liquid pipe 7, and the three paths of refrigerant sequentially passes through the first throttling mechanism 4, the first heat exchanger 3, the first four-way valve 50 and the first reversing node 52 of the first four-way valve 50 and the first reversing valve 50 to be compressed by the main compression mechanism 1, and the first path of refrigerant is completed once.

Example 11

As shown in fig. 14, this embodiment is also a large-scale air source heat pump capable of absorbing heat from outdoor air to defrost, continuously supplying heat during defrosting, and avoiding gas-liquid impact, and is an improvement of the scheme shown in fig. 7 of embodiment 6. The solution shown in fig. 7 has a principle leakage through the liquid return device 30 during normal operation, i.e. when the first solenoid valve 32 is opened during normal operation, a small portion of the high-pressure exhaust gas of the compression mechanism will leak into the first low-pressure gas pipe 6 through the first capillary tube 31 of the liquid return device 30, and the solution shown in fig. 14 of this embodiment can overcome the above-mentioned drawbacks of the solution shown in fig. 7.

The difference between the scheme shown in fig. 14 and the scheme shown in fig. 7 is that in the scheme shown in fig. 14, no liquid return device 30 is arranged, two groups of refrigerant heating coils, namely a first heating coil 101 and a second heating coil 102, are connected in parallel inside the heater 2, the connection relationship of the heater 2 in the system is that one end of the first heating coil 101 of the heater 2 is connected with the outlet end of the main compression mechanism 1, the other end of the first heating coil 101 of the heater 2 is connected with the high-pressure liquid pipe 7, one end of the second heating coil 102 of the heater 2 is connected with the outlet end of the first one-way valve 71 through the high-pressure exhaust pipe 11, and the other end of the second heating coil 102 of the heater 2 is also connected with the high-pressure liquid pipe 7. The air source heat pump can realize the heat supply function and the winter heat supply and defrosting function in the whole year operation process. The workflow under each function is as follows.

(1) Heating function

In operation, the first throttle mechanism 4 and the main compression mechanism 1 normally operate. The first reversing node 52 of the first four-way valve 50 communicates with the low-pressure node 53 of the first four-way valve 50, and the second reversing node 54 of the first four-way valve 50 communicates with the high-pressure node 51 of the first four-way valve 50.

The working flow under the function is that the low-pressure refrigerant gas from the first low-pressure gas pipe 6 is compressed by the main compression mechanism 1 and then discharged from the outlet end of the main compression mechanism and then divided into two paths, the first path sequentially passes through the inlet end of the heater 2, the first heating coil 101 of the heater 2 and the outlet end of the heater 2 and enters the high-pressure liquid pipe 7, the second path sequentially passes through the high-pressure gas pipe 5, the high-pressure node 51 of the first four-way valve 50, the second reversing node 54 of the first four-way valve 50, the inlet end of the first one-way valve 71, the outlet end of the first one-way valve 71, the high-pressure exhaust pipe 11, the inlet end of the heater 2 and the second heating coil 102 of the heater 2 and also enters the high-pressure liquid pipe 7, and the two paths of refrigerant liquid sequentially passes through the first throttling mechanism 4, the first heat exchanger 3 and the first reversing node 52 of the first four-way valve 50 and the low-pressure node 53 of the first low-pressure gas pipe 6 after being mixed in the high-pressure liquid pipe 7 and then enters the main compression mechanism 1, and is compressed again.

(2) Winter heating and defrosting function

The working flow is that when in operation, the low-pressure refrigerant gas from the first low-pressure gas pipe 6 enters the main compression mechanism 1 to be compressed, and the refrigerant is divided into two paths after being discharged from the outlet end of the main compression mechanism 1; the first path sequentially passes through the inlet end of the heater 2, the first heating coil 101 of the heater 2 and the outlet end of the heater 2 and enters the high-pressure liquid pipe 7, the second path enters the high-pressure gas pipe 5 and is divided into a third path which occupies most part and a fourth path which occupies a small part, the third path sequentially passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 needing defrosting, the first reversing node 52 of the first four-way valve 50 matched with the first heat exchanger 3 needing defrosting, the first throttling mechanism 4 matched with the first heat exchanger 3 needing defrosting and also enters the high-pressure liquid pipe 7, the fourth path refrigerant sequentially passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 needing defrosting, the second reversing node 54 of the first four-way valve 50 matched with the first heat exchanger 3 needing no defrosting, the inlet end of the first one-way valve 71 matched with the first heat exchanger 3 needing defrosting, the outlet end of the first one-way valve 71, the first throttling mechanism 4 matched with the first heat exchanger 3 needing defrosting, the high-pressure liquid pipe 7, the refrigerant sequentially passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 needing defrosting, the first heat exchanger 3 needing no defrosting, the high-pressure liquid pipe 2, the first heat exchanger 2 and the first heat exchanger 3 needing defrosting, and the high-exchanging heat exchange medium, the low-pressure node 53 of the first four-way valve 50, which is matched with the first heat exchanger 3 which does not need defrosting, returns to the first low-pressure gas pipe 6, and enters the main compression mechanism 1 again to be compressed, so that one cycle is completed.

In the solutions of all the above embodiments of the present invention, any one of the first check valve 71, the second check valve 72, and the third check valve 73 can be replaced by any one of a solenoid valve, a throttle mechanism with a shut-off function (e.g., an electronic expansion valve), or a flow rate adjusting mechanism.

In the above embodiments of the present invention, any one or both of the main compression mechanism 1 and the auxiliary compression mechanism 8 may be used, and any one of a scroll compressor, a screw compressor, a rolling rotor compressor, a sliding vane compressor, a centrifugal compressor, a digital scroll compressor, and a magnetic suspension compressor may be used, or any one or both of the main compression mechanism 1 and the auxiliary compression mechanism 8 may be used, or a variable capacity compressor (for example, a variable frequency compressor, a digital scroll compressor), or a fixed speed compressor may be used.

In the embodiments of the present invention, the main compression mechanism 1 and the auxiliary compression mechanism 8 may be a compressor unit composed of at least two variable capacity compressors or a compressor unit composed of at least two constant speed compressors, and the main compression mechanism 1 and the auxiliary compression mechanism 8 may be a compressor unit composed of at least one variable capacity compressor and at least one constant speed compressor.

In the solutions of all the above embodiments of the present invention, any one of the first heat exchanger 3 and the second heat exchanger 9 may be a refrigerant-water heat exchanger or another kind of heat exchanger, besides a refrigerant-air heat exchanger, and any one of a positive displacement heat exchanger, a plate heat exchanger, a shell-and-tube heat exchanger, or a double pipe heat exchanger may be used as the refrigerant-water heat exchanger. When either one of the first heat exchanger 3 and the second heat exchanger 9 is used as a refrigerant-air heat exchanger, a fin type heat exchanger is generally adopted, fins of the fin type heat exchanger are generally made of aluminum or aluminum alloy materials, and copper materials are also used in some special occasions.

In the solutions of all the above embodiments of the invention, one, even all, of the first and second throttle mechanisms 4, 10 can be replaced by a throttle mechanism with a shut-off function (e.g. an electronic expansion valve).

In the solutions of all the above embodiments of the invention, all the pipes are copper pipes.

Claims

1. A control method for an air source heat pump, the air source heat pump comprising a main compression mechanism (1), a heater (2), at least two first reversing devices (40), two first heat exchangers (3) and two first throttling mechanisms (4), and also comprising a liquid return device (30), wherein the outlet end of the liquid return device (30) is connected to the inlet end of the main compression mechanism (1) through a first low-pressure gas pipe (6), the outlet end of the main compression mechanism (1) is connected to a high-pressure liquid pipe (7) through the inlet end of the heater (2) and the outlet end of the heater (2), and the inlet end of the liquid return device (30) is connected to a pipeline between the outlet end of the main compression mechanism (1) and the inlet end of the heater (2) through a high-pressure gas pipe (5);

One of the first reversing devices (40), one of the first heat exchangers (3) and one of the first throttling mechanisms (4) constitutes a set of outdoor heat exchange units;

One end of the first throttling mechanism (4) is connected to the high-pressure liquid pipe (7), the other end of the first throttling mechanism (4) is connected to the reversing node (C) of the first reversing device through the first heat exchanger (3), the low-pressure node (B) of the first reversing device is connected to the first low-pressure gas pipe (6), and the high-pressure node (A) of the first reversing device is connected to the high-pressure gas pipe (5);

Its characteristics are: the control method of the air source heat pump is as follows:

1) In the heating function, the flow channel between the high-pressure node (A) of the first reversing device and its reversing node (C) is closed; the flow channel between the low-pressure node (B) of the first reversing device and its reversing node (C) is opened;

2) In winter, when any group of the first heat exchangers (3) needs to be defrosted under the heating and defrosting function, the first reversing device (40) matched with the first heat exchanger (3) that needs to be defrosted is switched, and the connection mode of the first reversing device (40) after switching is: the flow channel between the high-pressure node (A) of the first reversing device and its reversing node (C) is opened, and the flow channel between the low-pressure node (B) of the first reversing device and its reversing node (C) is closed; the first reversing device (40) matched with the first heat exchanger (3) that does not need to be defrosted is not switched, and the flow mode under the heating function is still maintained.

2. A control method for an air source heat pump, the air source heat pump comprising a main compression mechanism (1), a heater (2), at least two first reversing devices (40), two first heat exchangers (3) and two first throttling mechanisms (4), and also comprising an auxiliary compression mechanism (8); one of the first reversing devices (40), one of the first heat exchangers (3) and one of the first throttling mechanisms (4) constitutes a group of outdoor heat exchange units;

The inlet end of the auxiliary compression mechanism (8) is connected to the inlet end of the main compression mechanism (1) through a first low-pressure gas pipe (6); the outlet end of the main compression mechanism (1) is connected to the high-pressure liquid pipe (7) through the inlet end of the heater (2) and the outlet end of the heater (2) in sequence; the outlet end of the auxiliary compression mechanism (8) is connected to the high-pressure node (A) of the first reversing device through a high-pressure gas pipe (5);

One end of the first throttling mechanism (4) is connected to the high-pressure liquid pipe (7), the other end of the first throttling mechanism (4) is connected to the reversing node (C) of the first reversing device through the first heat exchanger (3), and the low-pressure node (B) of the first reversing device is connected to the first low-pressure gas pipe (6);

The first reversing device (40) is composed of a second solenoid valve (21) and a third solenoid valve (22); the connection mode is as follows: one end of the second solenoid valve (21) is connected to a high-pressure node (A) of the first reversing device, the other end of the second solenoid valve (21) is connected to a low-pressure node (B) of the first reversing device through the third solenoid valve (22), and the reversing node (C) of the first reversing device is connected to a pipeline between the second solenoid valve (21) and the third solenoid valve (22);

1) Under the heating function, the main compression mechanism (1) works normally, and the auxiliary compression mechanism (8) does not work; the second solenoid valve (21) is closed or opened; and the third solenoid valve (22) is opened;

2) In the winter heating and defrosting function, the main compression mechanism (1) and the auxiliary compression mechanism (8) work simultaneously; when any group of the first heat exchangers (3) needs to be defrosted, the second solenoid valve (21) matched with the first heat exchanger (3) that needs to be defrosted is opened, and the third solenoid valve (22) matched with the first heat exchanger (3) that needs to be defrosted is closed;

The second solenoid valve (21) matched with the first heat exchanger (3) that does not need defrosting is closed, and the third solenoid valve (22) matched with the first heat exchanger (3) that does not need defrosting is opened.

3. A control method for an air source heat pump, the air source heat pump comprising a main compression mechanism (1), a heater (2), at least two first four-way valves (50), two first heat exchangers (3), two first throttling mechanisms (4) and two first check valves (71), and also comprising an auxiliary compression mechanism (8) and a liquid return device (30);

The first four-way valve (50), the first heat exchanger (3), the first throttling mechanism (4) and the first check valve (71) constitute an outdoor heat exchange unit;

The inlet end of the auxiliary compression mechanism (8) is connected to the inlet end of the main compression mechanism (1) through a first low-pressure gas pipe (6); the outlet end of the main compression mechanism (1) is connected to one end of the first throttling mechanism (4) through the inlet end of the heater (2), the outlet end of the heater (2) and the high-pressure liquid pipe (7) in sequence; the outlet end of the auxiliary compression mechanism (8) is connected to the high-pressure node (51) of the first four-way valve through a high-pressure gas pipe (5);

The other end of the first throttling mechanism (4) is connected to the first reversing node (52) of the first four-way valve (50) through the first heat exchanger (3), the low-pressure node (53) of the first four-way valve is connected to the first low-pressure gas pipe (6), and the second reversing node (54) of the first four-way valve (50) is connected to the first low-pressure gas pipe (6) through the inlet end of the first one-way valve (71), the outlet end of the first one-way valve (71), the high-pressure exhaust pipe (11), and the liquid return device (30) in sequence; the control method of the air source heat pump is as follows:

1) Under the heating function, the main compression mechanism (1) works normally, and the auxiliary compression mechanism (8) does not work; the low-pressure node (53) of the first four-way valve is connected to its first reversing node (52); the high-pressure node (51) of the first four-way valve is connected to its second reversing node (54);

2) In the winter heating and defrosting function, the main compression mechanism (1) and the auxiliary compression mechanism (8) work simultaneously; when any group of the first heat exchangers (3) needs to be defrosted, the first four-way valve (50) matched with the first heat exchanger (3) that needs to be defrosted is switched; after the switching, the high-pressure node (51) of the first four-way valve is connected to its first reversing node (52); at the same time, the low-pressure node (53) of the first four-way valve is connected to its second reversing node (54); the first four-way valve (50) matched with the first heat exchanger (3) that does not need to be defrosted is not switched, and the flow mode under the heating function is still maintained.

4. A control method for an air source heat pump, the air source heat pump comprising a main compression mechanism (1), a heater (2), at least two first four-way valves (50), two first heat exchangers (3), two first throttling mechanisms (4) and two first one-way valves (71), and also comprising a liquid return device (30); one of the first four-way valves (50), one of the first heat exchangers (3), one of the first throttling mechanisms (4) and one of the first one-way valves (71) constitute a set of outdoor heat exchange units;

The inlet end of the main compression mechanism (1) is connected to the second reversing node (54) of the first four-way valve (50) in sequence through the first low-pressure gas pipe (6), the outlet end of the liquid return device (30), the inlet end of the liquid return device (30), the high-pressure exhaust pipe (11), the outlet end of the first one-way valve (71), and the inlet end of the first one-way valve (71); the first reversing node (52) of the first four-way valve (50) is connected to the outlet end of the main compression mechanism (1) in sequence through the first heat exchanger (3), the first throttling mechanism (4), the high-pressure liquid pipe (7), the outlet end of the heater (2), and the inlet end of the heater (2);

The high-pressure node (51) of the first four-way valve is connected to the pipeline between the outlet end of the main compression mechanism (1) and the inlet end of the heater (2) through the high-pressure gas pipe (5); the low-pressure node (53) of the first four-way valve is connected to the first low-pressure gas pipe (6); the control method of the air source heat pump is as follows:

1) In the heating function, the main compression mechanism (1) operates normally; the low-pressure node (53) of the first four-way valve is connected to its first reversing node (52); the high-pressure node (51) of the first four-way valve is connected to its second reversing node (54);

2) In the winter heating and defrosting function, the main compression mechanism (1) works; when any group of the first heat exchangers (3) needs to be defrosted, the first four-way valve (50) matched with the first heat exchanger (3) that needs to be defrosted is switched; after the switching, the high-pressure node (51) of the first four-way valve is connected to its first reversing node (52); at the same time, the low-pressure node (53) of the first four-way valve is connected to its second reversing node (54); the first four-way valve (50) matched with the first heat exchanger (3) that does not need to be defrosted is not switched, and the flow mode under the heating function is still maintained.

5. A control method for an air source heat pump, the air source heat pump comprising a main compression mechanism (1), a heater (2), at least two first four-way valves (50), two first heat exchangers (3), two first throttling mechanisms (4) and two first one-way valves (71), and also comprising a liquid return device (30); one of the first four-way valves (50), one of the first heat exchangers (3), one of the first throttling mechanisms (4) and one of the first one-way valves (71) constitute a set of outdoor heat exchange units;

The inlet end of the main compression mechanism (1) is connected to the outlet end of the main compression mechanism (1) via a first low-pressure gas pipe (6), an outlet end of a liquid return device (30), an inlet end of the liquid return device (30), and a high-pressure gas pipe (5) in sequence;

The high-pressure node (51) of the first four-way valve is connected to the high-pressure gas pipe (5); the first reversing node (52) of the first four-way valve (50) is connected to the second reversing node (54) of the first four-way valve (50) via the first heat exchanger (3), the first throttling mechanism (4), the high-pressure liquid pipe (7), the outlet end of the heater (2), the inlet end of the heater (2), the high-pressure exhaust pipe (11), the outlet end of the first check valve (71), and the inlet end of the first check valve (71); the low-pressure node (53) of the first four-way valve is connected to the first low-pressure gas pipe (6);

6. A control method for an air source heat pump, the air source heat pump comprising a main compression mechanism (1), a heater (2), a defrost control valve (90), at least two first reversing devices (40), two first heat exchangers (3) and two first throttling mechanisms (4);

The connection relationship of the above-mentioned components is as follows: the outlet end of the main compression mechanism (1) is connected to the reversing node (C) of the first reversing device through the inlet end of the heater (2), the outlet end of the heater (2), the high-pressure liquid pipe (7), the first throttling mechanism (4), and the first heat exchanger (3) in sequence; the inlet end of the main compression mechanism (1) is connected to the low-pressure node (B) of the first reversing device through the first low-pressure gas pipe (6); the high-pressure node (A) of the first reversing device is connected to the pipeline between the outlet end of the main compression mechanism (1) and the inlet end of the heater (2) in sequence through the high-pressure gas pipe (5) and the defrost control valve (90); the control method of the air source heat pump is as follows:

1) When the controller detects that the air source heat pump does not need to be defrosted, the defrost control valve (90) is in a closed state, and the reversing node (C) of the first reversing device is connected to its low-pressure node (B);

2) When the controller detects that any one of the first heat exchangers (3) needs to be defrosted, the reversing node (C) of the first reversing device matched with the first heat exchanger (3) that needs to be defrosted is connected to its high-pressure node (A), and at the same time, the reversing node (C) of the first reversing device matched with the first heat exchanger (3) that needs to be defrosted and its low-pressure node (B) are in a closed state; the defrost control valve (90) is opened;

3) When the controller detects that the defrosting of the first heat exchanger (3) requiring defrosting is completed, the defrost control valve (90) is closed to connect the reversing node (C) of the first reversing device matched with the first heat exchanger (3) requiring defrosting to its low-pressure node (B).

7. A control method for an air source heat pump, the air source heat pump comprising a main compression mechanism (1), a heater (2), at least two first four-way valves (50), two first heat exchangers (3), two first throttling mechanisms (4) and two first non-return valves (71), and an auxiliary compression mechanism (8), wherein the heater (2) comprises a first heating coil (101) and a second heating coil (102);

The inlet end of the auxiliary compression mechanism (8) is connected to the inlet end of the main compression mechanism (1) through a first low-pressure gas pipe (6); the outlet end of the main compression mechanism (1) is connected to one end of the first throttling mechanism (4) through a first heating coil (101) of the heater (2) and a high-pressure liquid pipe (7) in sequence; the outlet end of the auxiliary compression mechanism (8) is connected to the high-pressure node (51) of the first four-way valve through a high-pressure gas pipe (5);

The other end of the first throttling mechanism (4) is connected to the first reversing node (52) of the first four-way valve (50) through the first heat exchanger (3), the low-pressure node (53) of the first four-way valve is connected to the first low-pressure gas pipe (6), and the second reversing node (54) of the first four-way valve (50) is connected to the high-pressure liquid pipe (7) in sequence through the inlet end of the first one-way valve (71), the outlet end of the first one-way valve (71), the high-pressure exhaust pipe (11), and the second heating coil (102) of the heater (2); the control method of the air source heat pump is as follows:

1) Under the heating function, the main compression mechanism (1) and the auxiliary compression mechanism (8) both operate normally; the low-pressure node (53) of the first four-way valve is connected to its first reversing node (52); the high-pressure node (51) of the first four-way valve is connected to its second reversing node (54);

8. A control method for an air source heat pump, the air source heat pump comprising a main compression mechanism (1), a heater (2), at least two first four-way valves (50), two first heat exchangers (3), two first throttling mechanisms (4) and two first one-way valves (71), the heater (2) comprising a first heating coil (101) and a second heating coil (102); one first four-way valve (50), one first heat exchanger (3), one first throttling mechanism (4) and one first one-way valve (71) constitute a set of outdoor heat exchange units;

The inlet end of the main compression mechanism (1) is connected to the low-pressure node (53) of the first four-way valve through a first low-pressure gas pipe (6); the first reversing node (52) of the first four-way valve (50) is connected to the outlet end of the main compression mechanism (1) through a first heat exchanger (3), a first throttling mechanism (4), a high-pressure liquid pipe (7), and a first heating coil (101) of the heater (2) in sequence; the second reversing node (54) of the first four-way valve (50) is connected to the high-pressure liquid pipe (7) through an inlet end of a first check valve (71), an outlet end of the first check valve (71), a high-pressure exhaust pipe (11), and a second heating coil (102) of the heater (2) in sequence; the high-pressure node (51) of the first four-way valve is connected to the pipeline between the outlet end of the main compression mechanism (1) and the first heating coil (101) of the heater (2) through a high-pressure gas pipe (5);

2) In winter, under the heating and defrosting function, the main compression mechanism (1) works; when any group of the first heat exchangers (3) needs to be defrosted, the first four-way valve (50) matched with the first heat exchanger (3) that needs to be defrosted is switched; after the switching, the high-pressure node (51) of the first four-way valve is connected to its first reversing node (52); at the same time, the low-pressure node (53) of the first four-way valve is connected to its second reversing node (54); the first four-way valve (50) matched with the first heat exchanger (3) that does not need to be defrosted is not switched, and the flow mode under the heating function is still maintained.