Air source heat pump and control method thereof

Abstract

The present 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

Technical Field

[0001] The invention relates to an air source heat pump and a control method thereof, belonging to the technical field of refrigeration. Background Art

[0002] With the development of economy and the increasing requirements for environmental protection, the use of air source heat pumps is becoming more and more common. However, the existing single air source heat pump has a relatively small heating capacity. When used as a heat source for a centralized heating system, the heating area of ​​a single air source heat pump is not large. When it is necessary to undertake a large centralized heating area, multiple air source heat pumps must be used and connected in parallel through a water system to provide heating at the same time. This method is not conducive to the operation and regulation of the centralized heating system, nor is it conducive to the antifreeze of the air source heat pump water system. The hydraulic balance of the water system will also increase the cost of the entire heat pump system. In addition, the existing air source heat pumps generally use a reverse cycle hot air defrosting method for defrosting. As we all know, this defrosting method has the problem of mutual restriction of cold and heat. The energy waste caused by defrosting during the entire heating season is quite large. At the same time, the air source heat pump cannot provide heating normally during defrosting. In addition, other commonly used defrosting methods, such as hot air bypass defrosting, usually also require stopping heating during defrosting.

[0003] The invention patent application numbered 200610037147.3 published by Zhuhai Gree Electric Appliances Co., Ltd. on February 27, 2008 proposed a heat recovery multi-split system, the system components of which are as follows: Fig.15 shown.

[0004] from Fig.15 It can be seen that when heat exchanger 2 is a hot water heater and heat exchanger 3 is an outdoor air-refrigerant heat exchanger, a large air source heat pump system is formed. In this system, multiple heat exchangers 3 are connected in parallel between the high-pressure gas pipe 5, the medium-pressure liquid pipe 6 and the low-pressure gas pipe 7, and each heat exchanger 3 can independently play the role of evaporator and condenser. Therefore, the benefit brought under winter heating conditions is that when a heat exchanger 3 needs to be defrosted, the heat exchanger 3 can be switched from the evaporator to the condenser through the switching of the four-way valve 4, while other heat exchangers 3 continue to play the role of evaporator, absorb heat from the outdoor air, and continue to supply heat to users through the heat exchanger 2, thereby achieving the purpose of absorbing heat from the outdoor air to defrost and continuously supply heat, overcoming the defects of the reverse cycle hot air defrosting method.

[0005] but Fig.15The problem in the actual use of the system shown is that when working under winter heating conditions, the exhaust gas of the compressor 1 directly enters the heat exchanger 2 to produce hot water for users, and the refrigerant gas in the high-pressure gas pipe 5 is almost stagnant. Since the outer surface of the high-pressure gas pipe 5 dissipates heat to the air outside for a long time, the refrigerant gas will condense into liquid. If the refrigerant liquid cannot be discharged through the capillary 8 in time, it will mix with the superheated refrigerant vapor during defrosting and will be re-gasified, causing a sudden change in the pressure condition in the high-pressure gas pipe 5, making the four-way valve 4 easily damaged. In addition, Fig.15 During the startup phase of the system shown, since the high-pressure gas pipe 5 is in a cold state and the temperature is relatively low, and at this time, the exhaust pressure and temperature of the compressor 1 are both relatively low, a large amount of refrigerant liquid will be generated in the high-pressure gas pipe 5 during the startup phase. Because the capillary tube 8 has a relatively large resistance in order to reduce the gas leakage loss during the normal operation phase, it is impossible to discharge the refrigerant liquid generated by the warm pipe during the startup phase of the system in time. Therefore, during the startup phase, a gas-liquid shock will be generated in the high-pressure gas pipe 5, which will more easily damage the four-way valve 4 and disrupt the normal operation of the system. Summary of the invention

[0006] The object of the present invention is to provide an air source heat pump and a control method thereof which can absorb heat from outdoor air to defrost, can continuously supply heat during defrosting, and can avoid gas-liquid shock.

[0007] In order to overcome the problems existing in the above technology, the technical solution of the present invention to solve the technical problem is:

[0008] 1. An air source heat pump, comprising a main compression mechanism, a heater, at least two first reversing devices, two first heat exchangers and two first throttling mechanisms, characterized in that: the air source heat pump also includes a liquid return device, 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 the high-pressure liquid pipe through the inlet end of the heater and the outlet end of the heater in turn, and the inlet end of the liquid return device is connected to the pipeline between the outlet end of the main compression mechanism and the inlet end of the heater through a high-pressure gas pipe; one first reversing device, one first heat exchanger and one first throttling mechanism constitute a group of outdoor heat exchange units;

[0009] 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 the 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.

[0010] 2. An air source heat pump, comprising a main compression mechanism, a heater, at least two first reversing devices, two first heat exchangers and two first throttling mechanisms, characterized in that: the air source heat pump also includes an auxiliary compression mechanism, the inlet end of the auxiliary compression mechanism is connected to 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 to the high-pressure liquid pipe through the inlet end of the heater and the outlet end of the heater in turn; the outlet end of the auxiliary compression mechanism is connected to the high-pressure node of the first reversing device through a high-pressure gas pipe; one first reversing device, one first heat exchanger and one first throttling mechanism constitute a group of outdoor heat exchange units; one end of the first throttling mechanism is connected to the high-pressure liquid pipe, the other end of the first throttling mechanism is connected to the reversing node of the first reversing device through the first heat exchanger, and the low-pressure node of the first reversing device is connected to the first low-pressure gas pipe.

[0011] 3. An air source heat pump, comprising a main compression mechanism, a heater, at least one first reversing device, a first heat exchanger and a first throttling mechanism, characterized in that: the air source heat pump also includes an auxiliary compression mechanism, and at least one second reversing device, a second heat exchanger and a second throttling mechanism; one first reversing device, one first heat exchanger and one first throttling mechanism constitute a group of outdoor heat exchange units; one second reversing device, one second heat exchanger and one second throttling mechanism also constitute a group of outdoor heat exchange units;

[0012] The inlet end of the main compression mechanism is connected to the low-pressure node of the first reversing device through a first low-pressure gas pipe, and the outlet end of the main compression mechanism is connected to the first throttling mechanism and one end of the second throttling mechanism respectively through a heater inlet end, a heater outlet end, and a high-pressure liquid pipe in sequence; the inlet end of the auxiliary compression mechanism is connected to the low-pressure node of the second reversing device through a second low-pressure gas pipe, and the outlet end of the auxiliary compression mechanism is connected to the 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 to 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 to the high-pressure gas pipe;

[0013] The other end of the second throttling mechanism is connected to the reversing node of the second reversing device through a second heat exchanger, and the high-pressure node of the second reversing device is connected to the high-pressure gas pipe.

[0014] 4. An air source heat pump, comprising 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, characterized in that: the air source heat pump also includes an auxiliary compression mechanism and a liquid return device; one of the first four-way valves, one of the first heat exchangers, one of the first throttling mechanisms and one of the first one-way valves constitute a group of outdoor heat exchange units; the inlet end of the auxiliary compression mechanism is connected to 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 to one end of the first throttling mechanism through the inlet end of the heater, the outlet end of the heater and the high-pressure liquid pipe in sequence; the outlet end of the auxiliary compression mechanism is connected to the 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 to the first reversing node of the first four-way valve through the first heat exchanger, the low-pressure node of the first four-way valve is connected to the first low-pressure gas pipe, and the second reversing node of the first four-way valve is connected to the first low-pressure gas pipe in sequence through the inlet end of the first one-way valve, the outlet end of the first one-way valve, the high-pressure exhaust pipe and the liquid return device.

[0015] 5. An air source heat pump, comprising a main compression mechanism, a heater; at least one first four-way valve, a first heat exchanger, a first throttling mechanism and a first non-return valve; at least one second four-way valve, a second heat exchanger, a second throttling mechanism and a second non-return valve; characterized in that: the air source heat pump also includes an auxiliary compression mechanism and a liquid return device; one first four-way valve, one first heat exchanger, one first throttling mechanism and one first non-return valve constitute a group of outdoor heat exchange units; one second four-way valve, one second heat exchanger, one second throttling mechanism and one second non-return valve also constitute a group of outdoor heat exchange units;

[0016] The inlet end of the main compression mechanism is connected to the low-pressure node of the first four-way valve through the first low-pressure gas pipe, and the outlet end of the main compression mechanism is connected to one end of the first throttling mechanism and the second throttling mechanism respectively through the inlet end of the heater, the outlet end of the heater, and the high-pressure liquid pipe; the inlet end of the auxiliary compression mechanism is connected to the low-pressure node of the second four-way valve through the second low-pressure gas pipe, and the outlet end of the auxiliary compression mechanism is connected to the pipeline between the outlet end of the main compression mechanism and the inlet end of the heater through the high-pressure gas pipe; the high-pressure node of the second four-way valve is connected to the high-pressure gas pipe, and the third reversing node of the second four-way valve is connected to the high-pressure gas pipe. The device is connected to the other end of the second throttling mechanism, the fourth reversing node of the second four-way valve is connected to the first low-pressure gas pipe or the second low-pressure gas pipe through the second one-way valve inlet end, the second one-way valve outlet end, the high-pressure exhaust pipe, and the liquid return device in sequence; the high-pressure node of the first four-way valve is connected to the high-pressure gas pipe or the 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 to the other end of the first throttling mechanism through the first heat exchanger; the second reversing node of the first four-way valve is connected to the high-pressure exhaust pipe through the first one-way valve inlet end and the first one-way valve outlet end in sequence.

[0017] 6. An air source heat pump, comprising a main compression mechanism, a heater, at least two first four-way valves, two first heat exchangers, two first throttling mechanisms and two first check valves, characterized in that: the air source heat pump also includes a liquid return device;

[0018] One of the first four-way valves, one of the first heat exchangers, one of the first throttling mechanism and one of the first check valves constitutes an outdoor heat exchange unit;

[0019] The inlet end of the main compression mechanism is connected to the first reversing node of the first four-way valve in sequence through the first low-pressure gas pipe, the outlet end of the liquid return device, the inlet end of the liquid return device, the high-pressure exhaust pipe, the outlet end of the first one-way valve, and the inlet end of the first one-way valve, and the second reversing node of the first four-way valve is connected to the outlet end of the main compression mechanism in sequence through the first heat exchanger, the first throttling mechanism, the high-pressure liquid pipe, the outlet end of the heater, and the inlet end of the heater;

[0020] The high-pressure node of the first four-way valve is connected to the pipeline between the outlet end of the main compression mechanism and the inlet end of the heater through a high-pressure gas pipe; the low-pressure node of the first four-way valve is connected to the first low-pressure gas pipe.

[0021] 7. An air source heat pump, comprising 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, characterized in that: the air source heat pump also includes a liquid return device;

[0022] One of the first four-way valves, one of the first heat exchangers, one of the first throttling mechanism and one of the first check valves constitutes an outdoor heat exchange unit; the inlet end of the main compression mechanism is connected to the outlet end of the main compression mechanism through the first low-pressure gas pipe, the outlet end of the liquid return device, the inlet end of the liquid return device and the high-pressure gas pipe in sequence;

[0023] The high-pressure node of the first four-way valve is connected to the high-pressure gas pipe; the first reversing node of the first four-way valve is connected to the second reversing node of the first four-way valve through the first heat exchanger, the first throttling mechanism, the high-pressure liquid pipe, the heater outlet end, the heater inlet end, the high-pressure exhaust pipe, the first one-way valve outlet end, and the first one-way valve inlet end in sequence; the low-pressure node of the first four-way valve is connected to the first low-pressure gas pipe.

[0024] 8. An air source heat pump, comprising a main compression mechanism, a heater, at least two first reversing devices, two first heat exchangers and two first throttling mechanisms, characterized in that: the air source heat pump further comprises a defrost control valve; one of the first reversing devices, one of the first heat exchangers and one of the first throttling mechanisms constitute a set of outdoor heat exchange units;

[0025] The outlet end of the main compression mechanism is connected to the reversing node of the first reversing device 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 in sequence; the inlet end of the main compression mechanism is connected to 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 to the pipeline between the outlet end of the main compression mechanism and the inlet end of the heater through the high-pressure gas pipe and the defrost control valve in sequence.

[0026] 9. A control method for an air source heat pump, the air source heat pump comprising a main compression mechanism, a heater, a defrost control valve, at least two first reversing devices, two first heat exchangers and two first throttling mechanisms; one first reversing device, one first heat exchanger and one first throttling mechanism constitute a set of outdoor heat exchange units;

[0027] The connection relationship of the above-mentioned components is: the outlet end of the main compression mechanism is connected to the reversing node of the first reversing device 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 in sequence; the inlet end of the main compression mechanism is connected to 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 to the pipeline between the outlet end of the main compression mechanism and the inlet end of the heater through the high-pressure gas pipe and the defrost control valve in sequence; it is characterized in that: the control method of the air source heat pump is as follows:

[0028] 1) When the controller detects that the air source heat pump does not need to be defrosted, the defrost control valve is in a closed state, and the reversing node of the first reversing device is connected to the low-pressure node;

[0029] 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 that needs to be defrosted is connected to the high-pressure node, and at the same time, the reversing node of the first reversing device matched with the first heat exchanger that needs to be defrosted and the low-pressure node are in a closed state; the defrost control valve is opened;

[0030] 3) When the controller detects that the defrosting of the first heat exchanger that needs to be defrosted is completed, the defrost control valve is closed to connect the reversing node of the first reversing device matched with the first heat exchanger that needs to be defrosted with the low-pressure node.

[0031] 10. An air source heat pump, comprising 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, characterized in that: the air source heat pump also includes an auxiliary compression mechanism, the heater includes a first heating coil and a second heating coil; one first four-way valve, one first heat exchanger, one first throttling mechanism and one first one-way valve constitute a set of outdoor heat exchange units;

[0032] The inlet end of the auxiliary compression mechanism is connected to 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 to one end of the first throttling mechanism through the inlet end of the heater, the first heating coil of the heater, the outlet end of the heater, and the high-pressure liquid pipe in sequence;

[0033] The outlet end of the auxiliary compression mechanism is connected to the high-pressure node of the first four-way valve through a high-pressure gas pipe;

[0034] The other end of the first throttling mechanism is connected to the first reversing node of the first four-way valve through the first heat exchanger, the low-pressure node of the first four-way valve is connected to the first low-pressure gas pipe, and the second reversing node of the first four-way valve is connected to the high-pressure liquid pipe through the inlet end of the first one-way valve, the outlet end of the first 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 in sequence.

[0035] 11. An air source heat pump, comprising 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; wherein the air source heat pump further comprises an auxiliary compression mechanism, and the heater comprises a first heating coil and a second heating coil;

[0036] One first four-way valve, one first heat exchanger, one first throttling mechanism and one first check valve constitute a set of outdoor heat exchange units; one second four-way valve, one second heat exchanger, one second throttling mechanism and one second check valve also constitute a set of outdoor heat exchange units;

[0037] The inlet end of the main compression mechanism is connected to the low-pressure node of the first four-way valve through the first low-pressure gas pipe, and the outlet end of the main compression mechanism is connected to one end of the first throttling mechanism and the second throttling mechanism respectively through the inlet end of the heater, the first heating coil of the heater, the outlet end of the heater, and the high-pressure liquid pipe in sequence;

[0038] The inlet end of the auxiliary compression mechanism is connected to the low-pressure node of the second four-way valve through a second low-pressure gas pipe, and the outlet end of the auxiliary compression mechanism is connected to the 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 to the high-pressure gas pipe, the third reversing node of the second four-way valve is connected to 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 to the high-pressure liquid pipe through the inlet end of the second check valve, the outlet end of the second check 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 in sequence;

[0039] The high-pressure node of the first four-way valve is connected to the high-pressure gas pipe or the pipeline between the high-pressure node of the second four-way valve and the high-pressure gas pipe, and the first reversing node of the first four-way valve is connected to the other end of the first throttling mechanism through the first heat exchanger; the second reversing node of the first four-way valve is connected to the high-pressure exhaust pipe through the inlet end of the first one-way valve and the outlet end of the first one-way valve in sequence.

[0040] 12. An air source heat pump, comprising 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, characterized in that: the heater of the air source heat pump comprises a first heating coil and a second heating coil; one first four-way valve, one first heat exchanger, one first throttling mechanism and one first one-way valve constitute a group of outdoor heat exchange units; the inlet end of the main compression mechanism is connected to the low-pressure node of the first four-way valve through a first low-pressure gas pipe, and the first reversing node of the first four-way valve is connected to the outlet end of the main compression mechanism through the first heat exchanger, the first throttling mechanism, the high-pressure liquid pipe, the outlet end of the heater, the first heating coil of the heater, and the inlet end of the heater in sequence; the second reversing node of the first four-way valve is connected to the high-pressure liquid pipe through the inlet end of the first one-way valve, the outlet end of the first 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 in sequence; the high-pressure node of the first four-way valve is connected to the pipeline between the outlet end of the main compression mechanism and the inlet end of the heater through a high-pressure gas pipe.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. During operation, it can absorb heat from the outdoor air to defrost and provide continuous heating during defrosting;

[0043] 2. It can avoid gas-liquid shock;

[0044] 3. Simple structure;

[0045] 4. The present invention is applicable to industrial and civil heat pump equipment, and is particularly applicable to occasions where air is used as a low-temperature heat source. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a structural schematic diagram of embodiment 1 of the present invention;

[0047] Figure 2 It is a structural schematic diagram of embodiment 2 of the present invention;

[0048] Figure 3 This is a schematic diagram of the structure of a variation of Embodiment 2 of the present invention;

[0049] Figure 4 is a schematic structural diagram of Embodiment 3 of the present invention;

[0050] Figure 5 is a schematic structural diagram of Embodiment 4 of the present invention;

[0051] Figure 6 is a schematic structural diagram of Embodiment 5 of the present invention;

[0052] Figure 7is a schematic structural diagram of Embodiment 6 of the present invention;

[0053] Figure 8 is a structural schematic diagram of Embodiment 7 of the present invention;

[0054] Fig. 9 is a schematic structural diagram of Embodiment 8 of the present invention;

[0055] Fig.10 is a schematic structural diagram of a first reversing device in an embodiment of the present invention;

[0056] Fig.11 is a schematic structural diagram of a second reversing device in an embodiment of the present invention;

[0057] Fig.12 is a schematic diagram of the structure of Embodiment 9 of the present invention;

[0058] Fig.13 is a schematic structural diagram of Embodiment 10 of the present invention;

[0059] Fig.14 is a schematic diagram of the structure of embodiment 11 of the present invention;

[0060] Fig.15 It is a schematic diagram of the prior art structure. DETAILED DESCRIPTION

[0061] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0062] Example 1

[0063] like Figure 1 As shown, this embodiment is a large air source heat pump that can absorb heat from outdoor air for defrosting, can continuously provide heat during defrosting, and can avoid gas-liquid impact. The air source heat pump is used in occasions where there is a need for heating throughout the year. The entire device includes the following components: 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 includes a liquid return device 30. The liquid return device 30 is composed of a first solenoid valve 32, a first capillary tube 31 and a temperature sensor 34; their connection relationship in the system is: the inlet end of the first solenoid valve 32 is connected to the high-pressure gas pipe 5, the outlet end of the first solenoid valve 32 is connected to the first low-pressure gas pipe 6 through the first capillary tube 31, and the temperature sensor 34 is installed on the inlet end pipe or the outlet end pipe of the first solenoid valve 32. The inlet end of the first solenoid valve 32 is the inlet end of the liquid return device 30; the connection end of the first capillary tube 31 and the first low-pressure gas pipe 6 is the outlet end of the liquid return device 30.

[0064] exist Figure 1In the system shown, one first reversing device 40, one first heat exchanger 3 and one first throttling mechanism 4 constitute an outdoor heat exchange unit. The first reversing device 40 is an electromagnetic three-way valve 20, and the connection relationship of the electromagnetic three-way valve 20 in the system is: the normally open node of the electromagnetic three-way valve 20 is connected to the reversing node C of the first reversing device 40, any one of the two reversing nodes of the electromagnetic three-way valve 20 is connected to the high-pressure node A of the first reversing device 40, and the other reversing node of the electromagnetic three-way valve 20 is connected to the low-pressure node B of the first reversing device 40. The first throttling mechanism 4 is an electronic expansion valve.

[0065] The air source heat pump can realize the heating function and the heating and defrosting function in winter during the operation throughout the year. When working, the first heat exchanger 3 acts as an evaporator in the heating function to absorb heat from the environment; in the heating and defrosting function in winter, when any first heat exchanger 3 needs to be defrosted, it can also be converted into a condenser by switching the first reversing device 40 matched with it, and the heat absorbed from the outdoor air by other first heat exchangers 3 that do not need to be defrosted is used for defrosting. The heater 2 acts as a condenser throughout the year to provide heating for users. The working processes under each function are described as follows.

[0066] (1) Heating function

[0067] When working, the first throttling mechanism 4 works normally. The flow channel between the high-pressure node A and the switching node C of the first switching device 40 is closed, and the flow channel between the low-pressure node B and the switching node C of the first switching device 40 is opened.

[0068] The working process is as follows: after the refrigerant is discharged from the outlet of the main compression mechanism 1, it is divided into two paths; most of it passes through the inlet of the heater 2, the outlet 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 in sequence, and enters the inlet of the main compression mechanism 1; another small part enters the high-pressure gas pipe 5 and stagnates therein;

[0069] During operation, due to the heat dissipation on the surface of the high-pressure gas pipe 5, part of the refrigerant stagnant therein will be condensed into refrigerant liquid. When the temperature sensor 34 detects that the refrigerant liquid has a certain degree of subcooling relative to the refrigerant saturation temperature corresponding to the exhaust pressure of the main compression mechanism 1, the controller sends a command to open the first solenoid valve 32, so that the refrigerant liquid accumulated in the high-pressure gas pipe 5 is discharged into the first low-pressure gas pipe 6 through the first capillary tube 31; after mixing with the first path, it enters the main compression mechanism 1 and is compressed again, thus completing a cycle.

[0070] (2) Heating and defrosting function in winter

[0071] In this function, Figure 1 In the scheme shown, one group of first heat exchangers 3 that do not need to be defrosted is still an evaporator to absorb heat from outdoor air; another group of first heat exchangers 3 that need to be defrosted is converted into a condenser for defrosting; the heater 2 still supplies heat to the user; that is, one group of first heat exchangers 3 is used to absorb heat from the outdoor air, and the absorbed heat and the work consumed by the compressor are used together for heating the user and defrosting the other group of first heat exchangers 3; therefore, compared with the reverse cycle hot air defrosting, there is no problem of mutual offset of cold and heat, and the essence of this defrosting method of the present invention is to absorb heat from the outdoor air for defrosting; when a large air source heat pump has multiple groups of first heat exchangers 3, the defrosting of one group of first heat exchangers 3 will have a smaller impact on the heating supply of the air source heat pump; especially in actual projects, the selection of air source heat pumps is based on the most unfavorable working conditions. During operation, air source heat pumps usually work under partial load. Therefore, during defrosting, the user's heating demand can still be met by adjusting the output capacity of the air source heat pump.

[0072] During operation, the first reversing device 40 matched with the group of first heat exchangers 3 that need to be defrosted needs to be switched, and the communication mode of the first reversing device 40 after switching is: the flow channel between the high-pressure node A and the reversing node C of the first reversing device 40 is opened, and the flow channel between the low-pressure node B and the reversing node C of the first reversing device 40 is closed. During defrosting, the first throttling mechanism 4 matched with the group of first heat exchangers 3 that need to be defrosted controls the amount of refrigerant gas used for defrosting by setting the opening.

[0073] The working process is as follows: after the refrigerant is discharged from the outlet of the main compression mechanism 1, it is divided into two paths; the first path passes through the inlet end and 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 that needs to be defrosted, the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 that needs to be defrosted, the first heat exchanger 3 that needs to be defrosted, and the first throttling mechanism 4 matched with the first heat exchanger 3 that needs to be defrosted, and also enters the high-pressure liquid pipe 7; after the two paths of refrigerant liquid are mixed in the high-pressure liquid pipe 7, they pass through the first throttling mechanism 4 matched with the first heat exchanger 3 that does not need to be defrosted, the first heat exchanger 3 that does not need to be defrosted, the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 that does not need to be defrosted, the low-pressure node B of the first reversing device 40 matched with the first heat exchanger 3 that does not need to be defrosted, and the first low-pressure gas pipe 6 in sequence, and return 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 application, the first reversing device 40 may be, in addition to the electromagnetic three-way valve 20, the following solutions (such as Fig.10 shown):

[0074] 1) The first reversing device 40 is composed of the second solenoid valve 21 and the third solenoid valve 22; the connection method is: one end of the second solenoid valve 21 is connected to the high-pressure node A of the first reversing device 40, the other end of the second solenoid valve 21 is connected to the low-pressure node B of the first reversing device 40 through the third solenoid valve 22, and the reversing node C of the first reversing device 40 is connected to the pipeline between the second solenoid valve 21 and the third solenoid valve 22.

[0075] 2) The first reversing device 40 is composed of a first four-way valve 50; the second reversing node 54 of the first four-way valve 50 is always in a truncated state; its connection method is: the high-pressure node 51 of the first four-way valve 50 is connected to 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 to 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 to the reversing node C of the first reversing device 40.

[0076] 3) The first reversing device 40 is composed of a first four-way valve 50 and a second capillary tube 35. The connection mode of the first four-way valve 50 is as follows: the high-pressure node 51 of the first four-way valve 50 is connected to 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 to 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 to 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 to the 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.

[0077] Example 2

[0078] like Figure 2 As shown, this embodiment is also a large air source heat pump that can absorb heat from outdoor air for defrosting, can continuously supply heat during defrosting, and can avoid gas-liquid impact. The entire device includes the following components: a main compression mechanism 1, an auxiliary compression mechanism 8, a heater 2, at least two first reversing devices 40, two first heat exchangers 3 and two first throttling mechanisms 4.

[0079] exist Figure 2 In the system shown, one first reversing device 40, one first heat exchanger 3 and one first throttling mechanism 4 constitute an outdoor heat exchange unit. The first reversing device 40 is composed of a second solenoid valve 21 and a third solenoid valve 22, and their connection relationship in the system is as described in Example 1. The first throttling mechanism 4 is an electronic expansion valve.

[0080] The air source heat pump can realize the heating function and the heating and defrosting function in winter during the operation throughout the year. When working, the first heat exchanger 3 acts as an evaporator in the heating function to absorb heat from the environment; in the heating and defrosting function in winter, when any first heat exchanger 3 needs to be defrosted, it can also be converted into a condenser by switching the first reversing device 40 matched with it, and the heat absorbed from the outdoor air by other first heat exchangers 3 that do not need to be defrosted is used for defrosting. The heater 2 acts as a condenser throughout the year to provide heating for users. The working processes under each function are described as follows.

[0081] (1) Heating function

[0082] During operation, the first throttling mechanism 4 works normally, the second electromagnetic valve 21 is closed or opened, and the third electromagnetic valve 22 is opened. The main compression mechanism 1 works normally, and the auxiliary compression mechanism 8 does not work.

[0083] The working process is as follows: after the refrigerant is discharged from the outlet end of the main compression mechanism 1, it 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 third solenoid valve 22, the first low-pressure gas pipe 6, and enters the inlet end of the main compression mechanism 1 to complete a cycle.

[0084] (2) Heating and defrosting function in winter

[0085] In this function, the main compression mechanism 1 and the auxiliary compression mechanism 8 work simultaneously; Figure 2 In the scheme shown, one group of first heat exchangers 3 that do not need to be defrosted still absorbs heat from the outdoor air as an evaporator; another group of first heat exchangers 3 that need to be defrosted is converted into a condenser for defrosting; the heater 2 still provides heat to the user; that is, a group of first heat exchangers 3 absorbs heat from the outdoor air, and the absorbed heat and the work consumed by the compressor are used together for heating the user and defrosting the other group of first heat exchangers 3. During operation, the second solenoid valve 21 matched with the group of first heat exchangers 3 that need to be defrosted is opened, and the third solenoid valve 22 is closed; the first throttling mechanism 4 matched with the group of first heat exchangers 3 that need to be defrosted controls the exhaust volume of the auxiliary compression mechanism 8 used for defrosting by setting the opening. The second solenoid valve 21 matched with the first heat exchanger 3 that does not need to be defrosted is closed, and the third solenoid valve 22 is still opened.

[0086] Its working process is: when working, the low-pressure refrigerant gas in the first low-pressure gas pipe 6 is divided into two paths; the first path enters the main compression mechanism 1 to be compressed, and after the refrigerant is discharged from the outlet end of the main compression mechanism 1, it 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, it passes through the high-pressure gas pipe 5, the second solenoid valve 21 matching the first heat exchanger 3 that needs to be defrosted, the first heat exchanger 3 that needs to be defrosted, and the first throttling mechanism 4 matching the first heat exchanger 3 that needs to be defrosted, and also enters the high-pressure liquid pipe 7; after the two refrigerant liquids are mixed in the high-pressure liquid pipe 7, they pass through the first throttling mechanism 4 matching the first heat exchanger 3 that does not need to be defrosted, the first heat exchanger 3 that does not need to be defrosted, and the third solenoid valve 22 matching the first heat exchanger 3 that does not need to be defrosted, and return to the first low-pressure gas pipe 6 to complete a cycle.

[0087] Figure 3 The scheme shown is Figure 2 A variation of the scheme shown. Figure 3 In the scheme shown, the outlet end of the auxiliary compression mechanism 8 is not only connected to the high-pressure node A of the first reversing device 40 through the high-pressure gas pipe 5, but also connected to the pipeline between the main compression mechanism 1 and the heater 2 through the high-pressure gas pipe 5. Therefore, when the heat pump works in the heating function, the auxiliary compression mechanism 8 can also work normally, overcoming the problem that Figure 2 The solution shown has the defect that the auxiliary compression mechanism 8 cannot work normally when working under the heating function.

[0088] Example 3

[0089] like Figure 4 As shown, this embodiment is also a large air source heat pump that can absorb heat from outdoor air for defrosting, can continuously supply heat during defrosting, and can avoid gas-liquid impact. The entire device includes the following components: a main compression mechanism 1, an auxiliary compression mechanism 8, a heater 2; at least one first reversing device 40, a first heat exchanger 3 and a first throttling mechanism 4; at least one second reversing device 41, a second heat exchanger 9 and a second throttling mechanism 10.

[0090] exist Figure 4 In the system shown, one first reversing device 40, one first heat exchanger 3 and one first throttling mechanism 4 constitute an outdoor heat exchange unit. The first reversing device 40 is composed of a second solenoid valve 21 and a third solenoid valve 22, and their connection relationship in the system is as described in Example 1. The first throttling mechanism 4 and the second throttling mechanism 10 are electronic expansion valves. Similarly, in Figure 4In the system shown, one second reversing device 41, one second heat exchanger 9 and one second throttling mechanism 10 also constitute a set of outdoor heat exchange units. The second reversing device 41 is composed of a fourth solenoid valve 23 and a fifth solenoid valve 24, and their connection relationship in the system is: one end of the fourth solenoid valve 23 is connected to the high-pressure node A of the second reversing device 41, and the other end of the fourth solenoid valve 23 is connected to the low-pressure node B of the second reversing device 41 through the fifth solenoid valve 24, and the reversing node C of the second reversing device 41 is connected to the pipeline between the fourth solenoid valve 23 and the fifth solenoid valve 24. In addition to being composed of the fourth solenoid valve 23 and the fifth solenoid valve 24, the second reversing device 41 can also have the following solutions:

[0091] 1) The second reversing device 41 can also be formed by an electromagnetic three-way valve 20; its connection method is: the normally open node of the electromagnetic three-way valve 20 is connected to the reversing node C of the second reversing device 41, any one of the two reversing nodes of the electromagnetic three-way valve 20 is connected to the high-pressure node A of the second reversing device 41, and the other reversing node of the electromagnetic three-way valve 20 is connected to the low-pressure node B of the second reversing device 41.

[0092] 2) If Fig.11 As shown, the second reversing device 41 is composed of 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; the connection method is: the high-pressure node 81 of the second four-way valve 80 is connected to 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 to 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 to the reversing node C of the second reversing device 41.

[0093] 3) If Fig.11 As shown, the second reversing device 41 is composed of a second four-way valve 80 and a third capillary tube 36. They are connected in the following manner: the high-pressure node 81 of the second four-way valve 80 is connected to 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 to 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 to 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 to the 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.

[0094] The air source heat pump can also realize the heating function and the heating and defrosting function in winter during the operation throughout the year. When working, the first heat exchanger 3 and the second heat exchanger 9 act as evaporators in the heating function to absorb heat from the environment; in the heating and defrosting function in winter, when the first heat exchanger 3 needs to be defrosted, it is converted into a condenser by switching the first reversing device 40 matched with it, and the heat absorbed from the outdoor air by the second heat exchanger 9 that does not need to be defrosted is used for defrosting; similarly, when the second heat exchanger 9 needs to be defrosted, it is converted into a condenser by switching the second reversing device 41 matched with it, and the heat absorbed from the outdoor air by the first heat exchanger 3 that does not need to be defrosted is used for defrosting. The heater 2 acts as a condenser throughout the year to provide heating for users. The working processes under each function are described as follows.

[0095] (1) Heating function

[0096] During operation, the first throttling mechanism 4 and the second throttling mechanism 10 both work normally. The second solenoid valve 21 and the fourth solenoid valve 23 are closed, and the third solenoid valve 22 and the fifth solenoid valve 24 are opened. The main compression mechanism 1 and the auxiliary compression mechanism 8 both work normally.

[0097] The working process is as follows: 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 passes through the first throttling mechanism 4, the first heat exchanger 3, the reversing node C of the first reversing device 40, the third solenoid valve 22, the low-pressure node B of the first reversing device 40, and the first low-pressure gas pipe 6 in sequence, enters the main compression mechanism 1 and is compressed, and is then discharged into the outlet end pipeline of the main compression mechanism 1; the second path passes through the second throttling mechanism 10, the second heat exchanger 9, the reversing node C of the second reversing device 41, the fifth solenoid valve 24, the low-pressure node B of the second reversing device 41, and the second low-pressure gas pipe 12 in sequence, enters the auxiliary compression mechanism 8 and is compressed, and is then discharged into the outlet end pipeline of the main compression mechanism 1 through the high-pressure gas pipe 5; the two refrigerants are mixed in the outlet end pipeline of the main compression mechanism 1, and then pass through the heater 2 into the high-pressure liquid pipe 7, thereby completing a cycle.

[0098] (2) Heating and defrosting function in winter

[0099] Under this function, there are two operating conditions. One is that when the first heat exchanger 3 needs to be defrosted, the second heat exchanger 9 does not need to be defrosted and works normally, absorbing heat from the outdoor air for heating and defrosting of the first heat exchanger 3 respectively; the other is that when the second heat exchanger 9 needs to be defrosted, the first heat exchanger 3 does not need to be defrosted and works normally, absorbing heat from the outdoor air for heating and defrosting of the second heat exchanger 9 respectively. The working conditions are described as follows.

[0100] 1) When the first heat exchanger 3 needs to be defrosted, the second heat exchanger 9 works normally

[0101] At this time, the main compression mechanism 1 is not working, and the auxiliary compression mechanism 8 is working normally; the second solenoid valve 21 and the fifth solenoid valve 24 are open, and the third solenoid valve 22 and the fourth solenoid valve 23 are closed; the first throttling mechanism 4 controls the amount of refrigerant gas entering the first heat exchanger 3 for defrosting by setting the opening; the second throttling mechanism 10 is working normally. The working process is as follows: after the refrigerant is discharged from the outlet end of the auxiliary compression mechanism 8, it enters the high-pressure gas pipe 5 and is divided into two paths; the first path passes through the high-pressure node A of the first reversing device 40, the second solenoid valve 21, the reversing node C of the first reversing device 40, the first heat exchanger 3, and the first throttling mechanism 4 in sequence, and enters the high-pressure liquid pipe 7; the second path passes through the inlet end of the heater 2 and the outlet end of the heater 2 in sequence and also enters the high-pressure liquid pipe 7; after the two refrigerants are mixed in the high-pressure liquid pipe 7, they pass through the second throttling mechanism 10, the second heat exchanger 9, the reversing node C of the second reversing device 41, the fifth solenoid valve 24, the low-pressure node B of the second reversing device 41, and the second low-pressure gas pipe 12 in sequence, and enter the auxiliary compression mechanism 8 to be compressed, thereby completing a cycle.

[0102] 2) When the second heat exchanger 9 needs to be defrosted, the first heat exchanger works normally

[0103] At this time, the main compression mechanism 1 works normally, and the auxiliary compression mechanism 8 does not work; the second solenoid valve 21 and the fifth solenoid valve 24 are closed, and the third solenoid valve 22 and the fourth solenoid valve 23 are opened; the second throttling mechanism 10 controls the amount of refrigerant gas entering the second heat exchanger 9 for defrosting by setting the opening; the first throttling mechanism 4 works normally. The working process is as follows: after the refrigerant is discharged from the outlet end of the main compression mechanism 1, it is divided into two paths; the first path passes through the high-pressure gas pipe 5, the high-pressure node A of the second reversing device 41, the fourth solenoid valve 23, the reversing node C of the second reversing device 41, the second heat exchanger 9, and the second throttling mechanism 10 in turn, and enters the high-pressure liquid pipe 7; the second path passes through the inlet end of the heater 2 and the outlet end of the heater 2 in turn and also enters the high-pressure liquid pipe 7; after the two refrigerants are mixed in the high-pressure liquid pipe 7, they pass through the first throttling mechanism 4, the first heat exchanger 3, the reversing node C of the first reversing device 40, the third solenoid valve 22, the low-pressure node B of the first reversing device 40, and the first low-pressure gas pipe 6 in turn, and enter the main compression mechanism 1 to be compressed, thus completing a cycle.

[0104] Example 4

[0105] like Figure 5As shown, this embodiment is also a large air source heat pump that can absorb heat from outdoor air for defrosting, can continuously supply heat during defrosting, and avoid gas-liquid impact. The entire device includes the following components: 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 one-way valves 71, and also includes a liquid return device 30. The liquid return device 30 is composed of a first capillary tube 31; its connection relationship in the system is: the inlet end of the first capillary tube 31 is connected to the high-pressure exhaust pipe 11, and the outlet end of the first capillary tube 31 is connected to the first low-pressure gas pipe 6.

[0106] Figure 5 In the system shown, one first four-way valve 50, one first heat exchanger 3, one first throttling mechanism 4 and one first check valve 71 constitute an outdoor heat exchange unit. The first throttling mechanism 4 is an electronic expansion valve.

[0107] The air source heat pump can realize the heating function and the heating and defrosting function in winter during the operation throughout the year. When working, the first heat exchanger 3 absorbs heat from the environment as an evaporator under the heating function; under the heating and defrosting function in winter, when any first heat exchanger 3 needs to be defrosted, it can also be converted into a condenser by switching the first four-way valve 50 matched with it, and the heat absorbed from the outdoor air by other first heat exchangers 3 that do not need to be defrosted is used for defrosting and heating at the same time. The heater 2 acts as a condenser throughout the year to provide heating for users. The working processes under each function are described as follows.

[0108] (1) Heating function

[0109] When working, the first throttling mechanism 4 and the main compression mechanism 1 work normally; the auxiliary compression mechanism 8 does not work. The first reversing node 52 of the first four-way valve 50 is connected to 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 is connected to the high-pressure node 51 of the first four-way valve 50. The working process under this function is: after the refrigerant is discharged from the outlet of the main compression mechanism 1, it 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 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 in sequence, and enters the inlet end of the main compression mechanism 1, and is compressed again, thus completing a cycle.

[0110] (2) Heating and defrosting function in winter

[0111] In this function, both the main compression mechanism 1 and the auxiliary compression mechanism 8 work normally. One group of the first heat exchangers 3 that do not need to be defrosted still absorbs heat from the outdoor air as an evaporator; the other group of the first heat exchangers 3 that need to be defrosted is converted into a condenser for defrosting; the heater 2 still provides heat to the user; that is, one group of the first heat exchangers 3 absorbs heat from the outdoor air, and the absorbed heat and the work consumed by the compressor are used together for heating the user and defrosting of the other group of the first heat exchangers 3.

[0112] During operation, the first four-way valve 50 matched with the group of first heat exchangers 3 that need to be defrosted needs to be switched, and the communication mode of the first four-way valve 50 after switching is: the high-pressure node 51 of the first four-way valve 50 is connected with the first reversing node 52, and the low-pressure node 53 of the first four-way valve 50 is connected with the second reversing node 54. During defrosting, the first throttling mechanism 4 matched with the group of first heat exchangers 3 that need to be defrosted controls the exhaust volume of the auxiliary compression mechanism 8 used for defrosting by setting the opening.

[0113] Its working process is: when working, the low-pressure refrigerant gas in the first low-pressure gas pipe 6 is divided into two paths; the first path enters the main compression mechanism 1 to be compressed, and after the refrigerant is discharged from the outlet end of the main compression mechanism 1, it passes through the inlet end of the heater 2 and the outlet end of the heater 2 in sequence 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, it enters the high-pressure gas pipe 5 and is divided into the third path accounting for the vast majority and the fourth path accounting for a small part; the third path passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 that needs to be defrosted, the first reversing node 52 of the first four-way valve 50 matched with the first heat exchanger 3 that needs to be defrosted, the first heat exchanger 3 that needs to be defrosted, and the first throttling mechanism 4 matched with the first heat exchanger 3 that needs to be defrosted, and also enters the high-pressure liquid pipe 7; after the first and third refrigerants are mixed in the high-pressure liquid pipe 7, Then it passes through the first throttling mechanism 4 matched with the first heat exchanger 3 that does not need defrosting, the first heat exchanger 3 that does not need defrosting, the first reversing node 52 of the first four-way valve 50 matched with the first heat exchanger 3 that does not need defrosting, and the low-pressure node 53 of the first four-way valve 50 matched with the first heat exchanger 3 that does not need defrosting in turn, and returns to the first low-pressure gas pipe 6; the fourth refrigerant passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 that does not need defrosting, the second reversing node 54 of the first four-way valve 50 matched with the first heat exchanger 3 that does not need defrosting, the first one-way valve 71 matched with the first heat exchanger 3 that does not need defrosting, the high-pressure exhaust pipe 11, and the first capillary tube 31 in turn, and also returns to the first low-pressure gas pipe 6; after the two refrigerants are mixed in the first low-pressure gas pipe 6, they enter the main compression mechanism 1 and the auxiliary compression mechanism 8 again to be compressed, thereby completing one cycle.

[0114] In addition to being composed of the first capillary 31, the liquid return device 30 may also have the following solutions:

[0115] 1) If Figure 1 As shown, it is composed of a first electromagnetic valve 32 , a first capillary tube 31 and a temperature sensor 34 ; the connection method thereof is the same as that of embodiment 1. The temperature sensor 34 can also be arranged on a pipeline between the outlet end of the first electromagnetic valve 32 and the first capillary tube 31 .

[0116] 2) If Figure 7 As shown, it is composed of a first electromagnetic valve 32, a first capillary tube 31, a liquid accumulator 33 and a temperature sensor 34; their connection mode is as follows: the inlet end of the first electromagnetic valve 32 is connected to the 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 to the first low-pressure gas pipe 6 through the first capillary tube 31, and the temperature sensor 34 is installed on the pipeline between the outlet end of the liquid accumulator 33 and the inlet end of the first electromagnetic valve 32 or the 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.

[0117] In practical applications, Figure 5 In the further improved scheme, 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 through the high-pressure gas pipe 5, but also 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. Therefore, when the heat pump works in the heating function, the auxiliary compression mechanism 8 can also work normally, overcoming the problem that Figure 5 The solution shown has the defect that the auxiliary compression mechanism 8 cannot work normally when working under the heating function.

[0118] Example 5

[0119] like Figure 6 As shown, this embodiment is also a large air source heat pump that can absorb heat from outdoor air for defrosting, can continuously supply heat during defrosting, and can avoid gas-liquid impact. The entire device includes the following components: a main compression mechanism 1, an auxiliary compression mechanism 8, a heater 2; at least one first four-way valve 50, a first heat exchanger 3, a first throttling mechanism 4 and a first check valve 71; at least one second four-way valve 80, a second heat exchanger 9, a second throttling mechanism 10 and a second check valve 72.

[0120] exist Figure 6 In the system shown, 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 first throttling mechanism 4 and the second throttling mechanism 10 are electronic expansion valves. Figure 6In the system shown, the second four-way valve 80, the second heat exchanger 9, the second throttling mechanism 10 and the second one-way valve 72 also constitute a set of outdoor heat exchange units.

[0121] The air source heat pump can also realize the heating function and the heating and defrosting function in winter during the operation throughout the year. When working, the first heat exchanger 3 and the second heat exchanger 9 act as evaporators in the heating function to absorb heat from the environment; in the winter heating and defrosting function, when the first heat exchanger 3 needs to be defrosted, the first four-way valve 50 matched with it is switched to convert it into a condenser, and the heat absorbed from the outdoor air by the second heat exchanger 9 that does not need to be defrosted is used for defrosting; similarly, when the second heat exchanger 9 needs to be defrosted, the second four-way valve 80 matched with it is switched to convert it into a condenser, and the heat absorbed from the outdoor air by the first heat exchanger 3 that does not need to be defrosted is used for defrosting. The heater 2 acts as a condenser throughout the year to provide heating for users. The working processes under each function are described as follows.

[0122] (1) Heating function

[0123] During operation, the first throttling mechanism 4 and the second throttling mechanism 10 both work normally; the main compression mechanism 1 and the auxiliary compression mechanism 8 also work normally; the high-pressure node 51 of the first four-way valve 50 is connected to the second reversing node 54 of the first four-way valve 50, and the low-pressure node 53 of the first four-way valve 50 is connected to 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 connected to 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 connected to the third reversing node 82 of the second four-way valve 80.

[0124] The working process is as follows: 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 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 in sequence, and enters the first low-pressure gas pipe 6; the second path of refrigerant 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 in sequence, enters the auxiliary compression mechanism 8 and is compressed, and then enters the high-pressure gas pipe 5 and is divided into the third path accounting for the vast majority, the fourth path accounting for a small part, and the fifth path; the third path of refrigerant enters the outlet end pipeline of the main compression mechanism 1 through the high-pressure gas pipe 5; the fourth path of refrigerant passes through the first The high-pressure node 51 of the four-way valve 50, the second reversing node 54 of the first four-way valve 50, and the first non-return valve 71 enter the high-pressure exhaust pipe 11; the fifth refrigerant 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 non-return valve 72 in sequence, and also enters the high-pressure exhaust pipe 11; after the fourth and fifth refrigerants are mixed in the high-pressure exhaust pipe 11, they also enter the first low-pressure gas pipe 6 through the liquid return device 30, and after mixing with the first refrigerant in the first low-pressure gas pipe 6, they enter the main compression mechanism 1 to be compressed, and then are discharged into the outlet end pipeline of the main compression mechanism 1, and after mixing with the third refrigerant in the outlet end pipeline of the main compression mechanism 1, they pass through the inlet end of the heater 2 and the outlet end of the heater 2 in sequence and enter the high-pressure liquid pipe 7 again, thus completing one cycle.

[0125] (2) Heating and defrosting function in winter

[0126] Under this function, there are two operating conditions. One is that when the first heat exchanger 3 needs to be defrosted, the second heat exchanger 9 does not need to be defrosted, but works normally, absorbs heat from the outdoor air, and is used for heating and defrosting the first heat exchanger 3 respectively; the other is that when the second heat exchanger 9 needs to be defrosted, the first heat exchanger 3 does not need to be defrosted, but works normally, absorbs heat from the outdoor air, and is used for heating and defrosting the second heat exchanger 9 respectively. The working conditions are described as follows.

[0127] 1) When the first heat exchanger 3 needs to be defrosted, the second heat exchanger 9 works normally

[0128] At this time, the main compression mechanism 1 does not work, and the auxiliary compression mechanism 8 works normally; the first four-way valve 50 needs to be reversed, while the second four-way valve 80 remains unchanged, and its connection state is the same as that under the heating function; the connection state of the first four-way valve 50 after reversing is: the high-pressure node 51 of the first four-way valve 50 is connected to 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 is connected to 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; the second throttling mechanism 10 works normally.

[0129] The working process is as follows: after the refrigerant is discharged from the outlet end of the auxiliary compression mechanism 8, it enters the high-pressure gas pipe 5 and is divided into two paths; the first path 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 in sequence, and enters the high-pressure liquid pipe 7; the second path passes through the heater 2 and also enters the high-pressure liquid pipe 7; after the two refrigerants are mixed in the high-pressure liquid pipe 7, they 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 in sequence, and enter the auxiliary compression mechanism 8 to be compressed, thus completing one cycle.

[0130] 2) When the second heat exchanger 9 needs to be defrosted, the first heat exchanger 3 works normally

[0131] At this time, the main compression mechanism 1 works normally, and the auxiliary compression mechanism 8 does not work; the first four-way valve 50 does not need to be reversed, and its connection state is the same as that under the heating function; and the second four-way valve 80 needs to be reversed, and the connection state of the second four-way valve 80 after reversing is: the high-pressure node 81 of the second four-way valve 80 is connected to the third reversing node 82 of the second four-way valve 80, and the low-pressure node 83 of the second four-way valve 80 is connected to 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; the first throttling mechanism 4 works normally.

[0132] The working process is as follows: after the refrigerant is discharged from the outlet end of the main compression mechanism 1, it is divided into three paths; the first path 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 in sequence, and enters the high-pressure liquid pipe 7; the second path passes through the heater 2 and also enters the high-pressure liquid pipe 7; after the first and second refrigerants are mixed in the high-pressure liquid pipe 7, they pass 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 in sequence, and enter the first low-pressure gas pipe 6; the third refrigerant 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 non-return valve 71, the high-pressure exhaust pipe 11, and the liquid return device 30 in sequence, and also enters the first low-pressure gas pipe 6; after the two refrigerants are mixed in the first low-pressure gas pipe 6, they enter the main compression mechanism 1 to be compressed, and a cycle is completed.

[0133] Example 6

[0134] like Figure 7 As shown, this embodiment is also a large air source heat pump that can absorb heat from outdoor air for defrosting, can continuously supply heat during defrosting, and can avoid gas-liquid impact. The entire device includes the following components: 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 includes 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 accumulator 33 and a temperature sensor 34. The connection relationship between them in the system is described in Example 4.

[0135] Figure 7 In the system shown, one first four-way valve 50, one first heat exchanger 3, one first throttling mechanism 4 and one first check valve 71 constitute an outdoor heat exchange unit. The first throttling mechanism 4 is an electronic expansion valve.

[0136] The air source heat pump can realize the heating function and the heating and defrosting function in winter during the operation throughout the year. When working, the first heat exchanger 3 acts as an evaporator in the heating function to absorb heat from the environment; in the heating and defrosting function in winter, when any first heat exchanger 3 needs to be defrosted, it can also be converted into a condenser by switching the first four-way valve 50 matched with it, and the heat absorbed from the outdoor air by other first heat exchangers 3 that do not need to be defrosted is used for defrosting and heating at the same time. The heater 2 acts as a condenser throughout the year to provide heating for users. The working processes under each function are described as follows.

[0137] (1) Heating function

[0138] When working, the first throttling mechanism 4 and the main compression mechanism 1 work normally. The first reversing node 52 of the first four-way valve 50 is connected to 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 is connected to the high-pressure node 51 of the first four-way valve 50.

[0139] The working process under this function is: after the refrigerant is discharged from the outlet end of the main compression mechanism 1, it is divided into two paths; the first path 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 first reversing node 52 of the first four-way valve 50, and the low-pressure node 53 of the first four-way valve 50 in sequence, and enters the first low-pressure gas pipe 6; the second path 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 check valve 71, the high-pressure exhaust pipe 11, and the liquid return device 30 in sequence, and also enters the first low-pressure gas pipe 6; the two paths are mixed in the first low-pressure gas pipe 6; enter the inlet end of the main compression mechanism 1, and are compressed again, thus completing a cycle.

[0140] (2) Heating and defrosting function in winter

[0141] In this function, the main compression mechanism 1 works normally. One group of first heat exchangers 3 that do not need to be defrosted is still an evaporator to absorb heat from the outdoor air; the other group of first heat exchangers 3 that need to be defrosted is converted into a condenser for defrosting; the heater 2 still provides heat to the user; that is, one group of first heat exchangers 3 is used to absorb heat from the outdoor air, and the absorbed heat and the work consumed by the compressor are used together for heating the user and defrosting of the other group of first heat exchangers 3.

[0142] During operation, the first four-way valve 50 matched with the group of first heat exchangers 3 that need to be defrosted needs to be switched, and the communication mode of the first four-way valve 50 after switching is: the high-pressure node 51 of the first four-way valve 50 is connected with the first reversing node 52, and the low-pressure node 53 of the first four-way valve 50 is connected with the second reversing node 54. During defrosting, the first throttling mechanism 4 matched with the group of first heat exchangers 3 that need to be defrosted controls the amount of refrigerant gas used for defrosting by setting the opening.

[0143] The working process is as follows: after the refrigerant is discharged from the outlet end of the main compression mechanism 1, it is divided into three paths; the first path passes through 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 and a fourth path; 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 that needs to be defrosted, the first reversing node 52 of the first four-way valve 50 matched with the first heat exchanger 3 that needs to be defrosted, the first heat exchanger 3 that needs to be defrosted, and the first throttling mechanism 4 matched with the first heat exchanger 3 that needs to be defrosted, and also enters the high-pressure liquid pipe 7; after the first and third path refrigerants are mixed in the high-pressure liquid pipe 7, they sequentially pass through the first throttling mechanism 4 matched with the first heat exchanger 3 that does not need to be defrosted, the first throttling mechanism 4 matched with the first heat exchanger 3 that does not need to be defrosted, and the first The fourth refrigerant passes through the first heat exchanger 3, the first reversing node 52 of the first four-way valve 50 matching the first heat exchanger 3 that does not need defrosting, and the low-pressure node 53 of the first four-way valve 50 matching the first heat exchanger 3 that does not need defrosting, and returns to the first low-pressure gas pipe 6; the fourth refrigerant passes through the high-pressure node 51 of the first four-way valve 50 matching the first heat exchanger 3 that does not need defrosting, the second reversing node 54 of the first four-way valve 50 matching the first heat exchanger 3 that does not need defrosting, the first one-way valve 71 matching the first heat exchanger 3 that does not need defrosting, the high-pressure exhaust pipe 11, and the liquid return device 30 in sequence, and also returns to the first low-pressure gas pipe 6; after the two refrigerants are mixed in the first low-pressure gas pipe 6, they enter the main compression mechanism 1 to be compressed, and thus a cycle is completed.

[0144] The liquid return device 30 may also be composed of a first capillary tube 31 , or may be composed of a first solenoid valve 32 , a first capillary tube 31 and a temperature sensor 34 .

[0145] Example 7

[0146] like Figure 8 As shown, this embodiment is also a large air source heat pump that can absorb heat from outdoor air for defrosting, can continuously supply heat during defrosting, and avoid gas-liquid impact. The entire device includes the following components: 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 includes 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 accumulator 33 and a temperature sensor 34. The connection relationship between them in the system is described in Example 4.

[0147] Figure 8 In the system shown, one first four-way valve 50, one first heat exchanger 3, one first throttling mechanism 4 and one first check valve 71 constitute an outdoor heat exchange unit. The first throttling mechanism 4 is an electronic expansion valve.

[0148] The air source heat pump can realize the heating function and the heating and defrosting function in winter during the operation throughout the year. When working, the first heat exchanger 3 acts as an evaporator in the heating function to absorb heat from the environment; in the heating and defrosting function in winter, when any first heat exchanger 3 needs to be defrosted, it can also be converted into a condenser by switching the first four-way valve 50 matched with it, and the heat absorbed from the outdoor air by other first heat exchangers 3 that do not need to be defrosted is used for defrosting and heating at the same time. The heater 2 acts as a condenser throughout the year to provide heating for users. The working processes under each function are described as follows.

[0149] (1) Heating function

[0150] When working, the first throttling mechanism 4 and the main compression mechanism 1 work normally. The first reversing node 52 of the first four-way valve 50 is connected to 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 is connected to the high-pressure node 51 of the first four-way valve 50. The working process under this function is: after the refrigerant is discharged from the outlet end of the main compression mechanism 1, it enters the high-pressure gas pipe 5 and is divided into two paths; the first path passes through the high-pressure gas pipe 5 and the liquid return device 30 in sequence, and enters the first low-pressure gas pipe 6; the second path 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 check valve 71, the outlet end of the first check 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; the two paths are mixed in the first low-pressure gas pipe 6; enter the inlet end of the main compression mechanism 1, and are compressed again, thus completing a cycle.

[0151] (2) Heating and defrosting function in winter

[0152] In this function, the main compression mechanism 1 works normally. One group of first heat exchangers 3 that do not need defrosting works normally, and the evaporator still absorbs heat from the outdoor air; the other group of first heat exchangers 3 that need defrosting is converted into a condenser for defrosting; the heater 2 still provides heat to the user.

[0153] During operation, the first four-way valve 50 matched with the group of first heat exchangers 3 that need to be defrosted needs to be switched, and the communication mode of the first four-way valve 50 after switching is: the high-pressure node 51 of the first four-way valve 50 is connected with the first reversing node 52, and the low-pressure node 53 of the first four-way valve 50 is connected with the second reversing node 54. During defrosting, the first throttling mechanism 4 matched with the group of first heat exchangers 3 that need to be defrosted controls the amount of refrigerant gas used for defrosting by setting the opening.

[0154] The working process is as follows: after the refrigerant is discharged from the outlet end of the main compression mechanism 1, it enters the high-pressure gas pipe 5 and is divided into three paths; the first path passes through the high-pressure gas pipe 5 and the liquid return device 30 in sequence, and enters the first low-pressure gas pipe 6; the second path passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 that 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 that does not need to be defrosted, the first one-way valve 71 matched with the first heat exchanger 3 that does not need to be defrosted, the high-pressure exhaust pipe 11, and the heater 2, and enters the high-pressure liquid pipe 7; the third path passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 that needs to be defrosted, the first The first reversing node 52 of the four-way valve 50, the first heat exchanger 3 that needs to be defrosted, and the first throttling mechanism 4 matched with the first heat exchanger 3 that needs to be defrosted also enter the high-pressure liquid pipe 7; after the second and third refrigerants are mixed in the high-pressure liquid pipe 7, they pass through the first throttling mechanism 4 matched with the first heat exchanger 3 that does not need to be defrosted, the first heat exchanger 3 that does not need to be defrosted, the first reversing node 52 of the first four-way valve 50 matched with the first heat exchanger 3 that does not need to be defrosted, and the low-pressure node 53 of the first four-way valve 50 matched with the first heat exchanger 3 that does not need to be defrosted in turn, and also enter the first low-pressure gas pipe 6, and after being mixed with the first refrigerant in the first low-pressure gas pipe 6, they enter the main compression mechanism 1 to be compressed, thereby completing one cycle.

[0155] The liquid return device 30 may also be composed of a first capillary tube 31 ; or may be composed of a first solenoid valve 32 , a first capillary tube 31 , a liquid accumulator 33 and a temperature sensor 34 .

[0156] Example 8

[0157] like Fig. 9 As shown, this embodiment is also a large air source heat pump that can absorb heat from outdoor air to defrost, can continuously provide heat during defrosting, and avoid gas-liquid shock. The entire device includes the following components: 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 includes a defrost control valve 90. Fig. 9 In the system shown, one first reversing device 40, one first heat exchanger 3 and one first throttling mechanism 4 constitute an outdoor heat exchange unit. The first reversing device 40 is composed of a second solenoid valve 21 and a third solenoid valve 22, and their connection relationship in the system is as described in Example 1. The first throttling mechanism 4 is an electronic expansion valve; and the defrost control valve 90 is a solenoid valve.

[0158] The air source heat pump can realize the heating function and the heating and defrosting function in winter during the operation throughout the year. When working, the first heat exchanger 3 acts as an evaporator in the heating function to absorb heat from the environment; in the heating and defrosting function in winter, when any first heat exchanger 3 needs to be defrosted, it can also be converted into a condenser by switching the first reversing device 40 matched with it, and the heat absorbed from the outdoor air by other first heat exchangers 3 that do not need to be defrosted is used for defrosting. The heater 2 acts as a condenser throughout the year to provide heating for users. The working processes under each function are described as follows.

[0159] (1) Heating function

[0160] When working, the main compression mechanism 1 and the first throttling mechanism 4 work 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 process is as follows: after the refrigerant is discharged from the outlet of the main compression mechanism 1, it passes through the inlet of the heater 2, the outlet 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 third solenoid 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 of the main compression mechanism 1, and is compressed again, thus completing a cycle.

[0161] (2) Heating and defrosting function in winter

[0162] In this function, Fig. 9 In the scheme shown, one group of first heat exchangers 3 that do not need defrosting still works normally as evaporators and absorbs heat from outdoor air; another group of first heat exchangers 3 that need defrosting is converted into condensers for defrosting; the heater 2 still supplies heat to the user; that is, one group of first heat exchangers 3 is used to absorb heat from the outdoor air, and the absorbed heat and the work consumed by the compressor are used together for heating the user and defrosting of another group of first heat exchangers 3.

[0163] During operation, the first reversing device 40 matched with the group of first heat exchangers 3 that need to be defrosted needs to be switched, that is, 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. During defrosting, the first throttling mechanism 4 matched with the group of first heat exchangers 3 that need to be defrosted controls the amount of refrigerant gas used for defrosting by setting the opening. The first reversing device 40 matched with the first heat exchanger 3 that does not need to be defrosted does not need to be switched; the defrost control valve 90 is opened.

[0164] The working process is as follows: after the refrigerant is discharged from the outlet end of the main compression mechanism 1, it is divided into two paths; the first path passes through the heater 2 and then enters the high-pressure liquid pipe 7; the second path passes through the defrost 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 that needs to be defrosted, the second solenoid valve 21 of the first reversing device 40 matched with the first heat exchanger 3 that needs to be defrosted, the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 that needs to be defrosted, the first heat exchanger 3 that needs to be defrosted, and the first throttling mechanism 4 matched with the first heat exchanger 3 that needs to be defrosted, and also Enter the high-pressure liquid pipe 7; after the two refrigerant liquids are mixed in the high-pressure liquid pipe 7, they pass through the first throttling mechanism 4 matched with the first heat exchanger 3 that does not need defrosting, the first heat exchanger 3 that does not need defrosting, the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 that does not need defrosting, the third solenoid valve 22 matched with the first heat exchanger 3 that does not need defrosting, the low-pressure node B of the first reversing device 40 matched with the first heat exchanger 3 that does not need defrosting, and the first low-pressure gas pipe 6 in turn, return to the inlet end of the main compression mechanism 1, enter the main compression mechanism 1 and be compressed again, thereby completing a cycle.

[0165] In addition to being composed of the second solenoid valve 21 and the third solenoid valve 22, the first reversing device 40 may also have the following solutions: 1) being composed of the solenoid three-way valve 20, and the connection relationship in the system is detailed in Example 1.

[0166] 2) The first reversing device 40 is composed of a first four-way valve 50; the second reversing node 54 of the first four-way valve 50 is always in a truncated state; its connection method is: the high-pressure node 51 of the first four-way valve 50 is connected to 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 to 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 to the reversing node C of the first reversing device 40.

[0167] 3) The first reversing device 40 is composed of a first four-way valve 50 and a second capillary tube 35. The connection mode of the first four-way valve 50 is as follows: the high-pressure node 51 of the first four-way valve 50 is connected to 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 to 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 to 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 to the 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.

[0168] In this embodiment Fig. 9 During the operation of the scheme shown, the control method of the air source heat pump is as follows:

[0169] 1) When the controller detects that the air source heat pump does not need to be defrosted, that is, during normal operation, the defrost control valve 90 is in a closed state, and the reversing node C of the first reversing device 40 is connected to the low-pressure node B; Fig. 9 In the illustrated solution, the third solenoid valve 22 is open; the second solenoid valve 21 can be closed or open.

[0170] 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 that needs to be defrosted and the high-pressure node A is connected, and at the same time, the channel between the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 that needs to be defrosted and the low-pressure node B is closed (i.e., in Fig. 9 In the scheme shown, the second solenoid valve 21 is opened and the third solenoid valve 22 is closed); the defrost control valve 90 is opened; the first throttling mechanism 4 matched with the first heat exchanger 3 that needs to be defrosted controls the amount of refrigerant gas used for defrosting by setting the opening degree; the channel between the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 that does not need to be defrosted and the high-pressure node A is closed, and at the same time, the channel between the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 that does not need to be defrosted and the low-pressure node B is in an open state, that is: in Fig. 9 In the illustrated embodiment, the second solenoid valve 21 is closed and the third solenoid valve 22 is opened.

[0171] 3) When the controller detects that the defrosting of the first heat exchanger 3 that needs to be defrosted is completed, the defrost control valve 90 is closed, so that the reversing node C of the first reversing device 40 matched with the first heat exchanger 3 that needs to be defrosted is connected to the low-pressure node B. Fig. 9 In the illustrated solution, the third solenoid valve 22 is open; the second solenoid valve 21 can be in a closed state or an open state.

[0172] Example 9

[0173] like Fig.12 As shown, this embodiment is also a large air source heat pump that can absorb heat from outdoor air for defrosting, can continuously supply heat during defrosting, and avoid gas-liquid shock; it is a modification of embodiment 4 Figure 5 Improvements of the scheme shown. Figure 5 In the normal working process of the scheme shown, there is a principle leakage through the liquid return device 30, that is, when the auxiliary compression mechanism 8 is working normally, a small part of the high-pressure exhaust gas of the compression mechanism will leak into the first low-pressure gas pipe 6 through the first capillary 31 of the liquid return device 30; at the same time, Figure 5 In the scheme shown, there is also a defect that the auxiliary compression mechanism 8 cannot work normally under the heating function, and this embodiment Fig.12 The solution shown can overcome Figure 5The above-mentioned defects of the shown scheme.

[0174] Fig.12 The scheme shown is Figure 5 The difference between the schemes shown is that: Fig.12 There is no liquid return device 30 in the illustrated scheme, and two groups of refrigerant heating coils are connected in parallel inside the heater 2, namely: the first heating coil 101 and the second heating coil 102; the connection relationship of the heater 2 in the system is: one end of the first heating coil 101 of the heater 2 is connected to the outlet end of the main compression mechanism 1, and the other end of the first heating coil 101 of the heater 2 is connected to the high-pressure liquid pipe 7; one end of the second heating coil 102 of the heater 2 is connected to 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 to the high-pressure liquid pipe 7. The air source heat pump can realize the heating function during the operation throughout the year, as well as the heating and defrosting function in winter. The working processes under each function are described as follows.

[0175] (1) Heating function

[0176] When working, the first throttling mechanism 4, the main compression mechanism 1, and the auxiliary compression mechanism 8 all work normally. The first reversing node 52 of the first four-way valve 50 is connected to 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 is connected to the high-pressure node 51 of the first four-way valve 50.

[0177] The working process under this function is as follows: a part of the low-pressure refrigerant gas from the first low-pressure gas pipe 6 is compressed by the main compression mechanism 1, discharged from its outlet end, 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 in sequence, and enters the high-pressure liquid pipe 7; another part of the low-pressure refrigerant gas from the first low-pressure gas pipe 6 is compressed by the auxiliary compression mechanism 8, discharged from its outlet end, 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, and the first check valve 71 in sequence to enter The refrigerant liquids of the two paths are mixed in the high-pressure liquid pipe 7, and then pass 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 in turn, and enter the first low-pressure gas pipe 6, and are divided into two paths; they enter the inlet ends of the main compression mechanism 1 and the auxiliary compression mechanism 8 respectively, and are compressed again, thus completing a cycle.

[0178] (2) Heating and defrosting function in winter

[0179] In this function, both the main compression mechanism 1 and the auxiliary compression mechanism 8 work normally. One group of the first heat exchangers 3 that do not need to be defrosted still absorbs heat from the outdoor air as an evaporator; the other group of the first heat exchangers 3 that need to be defrosted is converted into a condenser for defrosting; the heater 2 still provides heat to the user; that is, one group of the first heat exchangers 3 absorbs heat from the outdoor air, and the absorbed heat and the work consumed by the compressor are used together for heating the user and defrosting of the other group of the first heat exchangers 3.

[0180] During operation, the first four-way valve 50 matched with the group of first heat exchangers 3 that need to be defrosted needs to be switched, and the communication mode of the first four-way valve 50 after switching is: the high-pressure node 51 of the first four-way valve 50 is connected with the first reversing node 52, and the low-pressure node 53 of the first four-way valve 50 is connected with the second reversing node 54. During defrosting, the first throttling mechanism 4 matched with the group of first heat exchangers 3 that need to be defrosted controls the amount of refrigerant gas used for defrosting by setting the opening.

[0181] Its working process is: when working, the low-pressure refrigerant gas in the first low-pressure gas pipe 6 is divided into two paths; the first path enters the main compression mechanism 1 to be compressed, and after the refrigerant is discharged from the outlet end of the main compression mechanism 1, it 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 in sequence 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, it enters the high-pressure gas pipe 5 and is divided into the third path accounting for the vast majority and the fourth path accounting for a small part; the third path passes through the high-pressure node 51 of the first four-way valve 50 matching the first heat exchanger 3 that needs to be defrosted, the first reversing node 52 of the first four-way valve 50 matching the first heat exchanger 3 that needs to be defrosted, the first heat exchanger 3 that needs to be defrosted, and the first throttling mechanism 4 matching the first heat exchanger 3 that needs to be defrosted, and also enters the high-pressure liquid pipe 7; the fourth path refrigerant passes through the first four-way valve 50 that does not need to be defrosted in sequence The high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3, the second reversing node 54 of the first four-way valve 50 matched with the first heat exchanger 3 that does not need to be defrosted, the first one-way valve 71 matched with the first heat exchanger 3 that does not need to be defrosted, 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 also enter the high-pressure liquid pipe 7; after the first, third and fourth refrigerants are mixed in the high-pressure liquid pipe 7, they pass through the first throttling mechanism 4 matched with the first heat exchanger 3 that does not need to be defrosted, the first heat exchanger 3 that does not need to be defrosted, the first reversing node 52 of the first four-way valve 50 matched with the first heat exchanger 3 that does not need to be defrosted, and the low-pressure node 53 of the first four-way valve 50 matched with the first heat exchanger 3 that does not need to be defrosted, and return to the first low-pressure gas pipe 6; they enter the main compression mechanism 1 and the auxiliary compression mechanism 8 again to be compressed, thereby completing one cycle.

[0182] Fig.12 Improvement plan: Fig.12 In the scheme shown, in order to prevent the refrigerant liquid in the high-pressure liquid pipe 7 from entering the high-pressure exhaust pipe 11 through the second heating coil 102 of the heater 2 under the heating and defrosting function in winter, a third one-way valve 73 can be added between the second heating coil 102 and the high-pressure liquid pipe 7. At this time, the third one-way valve 73 is connected in the system as follows: the inlet end of the third one-way valve 73 is connected to 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 to the high-pressure liquid pipe 7.

[0183] Example 10

[0184] like Fig.13 As shown, this embodiment is also a large air source heat pump that can absorb heat from outdoor air for defrosting, can continuously supply heat during defrosting, and avoid gas-liquid shock; it is a modification of embodiment 5 Figure 6 Improvements of the scheme shown. Figure 6 In the normal working process of the scheme shown, there is a principle leakage through the liquid return device 30, that is, in normal working, when the first solenoid valve 32 is opened, a small part of the high-pressure exhaust gas of the compression mechanism will leak into the first low-pressure gas pipe 6 through the first capillary 31 of the liquid return device 30, and the present embodiment Fig.13 The solution shown can overcome Figure 6 The above-mentioned defects of the shown solution.

[0185] Fig.13 The scheme shown is Figure 6 The difference between the schemes shown is that: Fig.13 There is no liquid return device 30 in the illustrated scheme, and two groups of refrigerant heating coils are connected in parallel inside the heater 2, namely: the first heating coil 101 and the second heating coil 102; the connection relationship of the heater 2 in the system is: one end of the first heating coil 101 of the heater 2 is connected to the outlet end of the main compression mechanism 1 and the high-pressure gas pipe 5, and the other end of the first heating coil 101 of the heater 2 is connected to the high-pressure liquid pipe 7; one end of the second heating coil 102 of the heater 2 is connected to 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 to the high-pressure liquid pipe 7. The air source heat pump can realize the heating function and the winter heating and defrosting function during the operation throughout the year. The working processes under each function are described as follows.

[0186] (1) Heating function

[0187] During operation, the first throttling mechanism 4 and the second throttling mechanism 10 both work normally; the main compression mechanism 1 and the auxiliary compression mechanism 8 also work normally; the high-pressure node 51 of the first four-way valve 50 is connected to the second reversing node 54 of the first four-way valve 50, and the low-pressure node 53 of the first four-way valve 50 is connected to 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 connected to 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 connected to the third reversing node 82 of the second four-way valve 80.

[0188] Its working process is as follows: the refrigerant liquid entering the high-pressure liquid pipe 7 is divided into two paths; the first path of refrigerant 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 in sequence, enters the first low-pressure gas pipe 6, is compressed by the main compression mechanism 1, and then enters the outlet end pipeline of the main compression mechanism 1; the second path of refrigerant 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, the second low-pressure gas pipe 12 in sequence, enters the auxiliary compression mechanism 8 and is compressed, and then enters the high-pressure gas pipe 5 and is divided into the third path accounting for the vast majority, the fourth path accounting for a small part, and the fifth path; the third path of refrigerant also enters the outlet end pipeline of the main compression mechanism 1 through the high-pressure gas pipe 5, mixes with the first path of refrigerant in the outlet end pipeline of the main compression mechanism 1, and then passes through in sequence. The fourth refrigerant 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 fourth refrigerant 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 check valve 71, and the outlet end of the first check valve 71 in sequence to enter the high-pressure exhaust pipe 11; the fifth refrigerant 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, the inlet end of the second check valve 72, and the outlet end of the second check valve 72 in sequence to enter the high-pressure exhaust pipe 11; after the fourth and fifth refrigerants are mixed in the high-pressure exhaust pipe 11, they pass through the inlet end of the heater 2, the second heating coil 102 of the heater 2, and the outlet end of the heater 2 in sequence to enter the high-pressure liquid pipe 7, and after mixing with the first and third refrigerants in the high-pressure liquid pipe 7, they are divided into two paths again; one cycle is completed.

[0189] (2) Heating and defrosting function in winter

[0190] Under this function, there are two operating conditions. One is that when the first heat exchanger 3 needs to be defrosted, the second heat exchanger 9 does not need to be defrosted, but works normally, absorbs heat from the outdoor air, and is used for heating and defrosting the first heat exchanger 3 respectively; the other is that when the second heat exchanger 9 needs to be defrosted, the first heat exchanger 3 does not need to be defrosted, but works normally, absorbs heat from the outdoor air, and is used for heating and defrosting the second heat exchanger 9 respectively. The working conditions are described as follows.

[0191] 1) When the first heat exchanger 3 needs to be defrosted, the second heat exchanger 9 works normally

[0192] At this time, the main compression mechanism 1 does not work, and the auxiliary compression mechanism 8 works normally; the first four-way valve 50 needs to be reversed, while the second four-way valve 80 remains unchanged, and its connection state is the same as that under the heating function; the connection state of the first four-way valve 50 after reversing is: the high-pressure node 51 of the first four-way valve 50 is connected to 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 is connected to 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; the second throttling mechanism 10 works normally.

[0193] Its working process is as follows: after the refrigerant is discharged from the outlet end of the auxiliary compression mechanism 8, it enters the high-pressure gas pipe 5 and is divided into three paths; the first path of refrigerant 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, the first throttling mechanism 4 in turn, and enters the high-pressure liquid pipe 7; the second path of refrigerant 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 in turn, and also enters the high-pressure liquid pipe 7; the third path of refrigerant passes through the high-pressure node 81 of the second four-way valve 80, the second four-way valve 81, and the second four-way valve 81 in turn. The fourth reversing node 84 of 80, the inlet end of the second one-way valve 72, the outlet end of the second one-way valve 72, 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 also enter the high-pressure liquid pipe 7; after the three refrigerants are mixed in the high-pressure liquid pipe 7, they 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 in sequence, and enter the auxiliary compression mechanism 8 to be compressed, thereby completing a cycle.

[0194] 2) When the second heat exchanger 9 needs to be defrosted, the first heat exchanger 3 works normally

[0195] At this time, the main compression mechanism 1 works normally, and the auxiliary compression mechanism 8 does not work; the first four-way valve 50 does not need to be reversed, and its connection state is the same as that under the heating function; and the second four-way valve 80 needs to be reversed, and the connection state of the second four-way valve 80 after reversing is: the high-pressure node 81 of the second four-way valve 80 is connected to the third reversing node 82 of the second four-way valve 80, and the low-pressure node 83 of the second four-way valve 80 is connected to 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; the first throttling mechanism 4 works normally.

[0196] Its working process is as follows: after the refrigerant is discharged from the outlet end of the main compression mechanism 1, it is divided into three paths; the first path 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, the second throttling mechanism 10 in sequence, and enters the high-pressure liquid pipe 7; the second path 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 in sequence, and also enters the high-pressure liquid pipe 7; the third path of refrigerant passes through the high-pressure gas pipe 5, the high-pressure node 51 of the first four-way valve 50, the first four-way valve 51 ... second heat exchanger 9, the second throttling mechanism 10, and the second throttling mechanism 10 in sequence, and enters the high-pressure liquid pipe 7; The second reversing node 54 of the 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 also enter the high-pressure liquid pipe 7; after the three refrigerants are mixed in the high-pressure liquid pipe 7, they pass 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 the first low-pressure gas pipe 6 in sequence, and enter the main compression mechanism 1 to be compressed, thereby completing a cycle.

[0197] Embodiment 11

[0198] like Fig.14 As shown, this embodiment is also a large air source heat pump that can absorb heat from outdoor air to defrost, can continuously provide heat during defrosting, and avoid gas-liquid shock; it is a modification of embodiment 6 Figure 7 Improvements of the scheme shown. Figure 7 In the normal working process of the scheme shown, there is a principle leakage through the liquid return device 30, that is, in normal working, when the first solenoid valve 32 is opened, a small part of the high-pressure exhaust gas of the compression mechanism will leak into the first low-pressure gas pipe 6 through the first capillary 31 of the liquid return device 30, and the present embodiment Fig.14 The solution shown can overcome Figure 7 The above-mentioned defects of the shown solution.

[0199] Fig.14 The scheme shown is Figure 7 The difference between the schemes shown is that Fig.14There is no liquid return device 30 in the illustrated scheme, and two groups of refrigerant heating coils are connected in parallel inside the heater 2, namely: the first heating coil 101 and the second heating coil 102; the connection relationship of the heater 2 in the system is: one end of the first heating coil 101 of the heater 2 is connected to the outlet end of the main compression mechanism 1, and the other end of the first heating coil 101 of the heater 2 is connected to the high-pressure liquid pipe 7; one end of the second heating coil 102 of the heater 2 is connected to 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 to the high-pressure liquid pipe 7. The air source heat pump can realize the heating function during the operation throughout the year, as well as the heating and defrosting function in winter. The working processes under each function are described as follows.

[0200] (1) Heating function

[0201] When working, the first throttling mechanism 4 and the main compression mechanism 1 work normally. The first reversing node 52 of the first four-way valve 50 is connected to 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 is connected to the high-pressure node 51 of the first four-way valve 50 .

[0202] The working process under this function is: the low-pressure refrigerant gas from the first low-pressure gas pipe 6 is compressed by the main compression mechanism 1, and is discharged from its outlet end and is divided into two paths; the first path 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 in sequence, and enters the high-pressure liquid pipe 7; the second path 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 check valve 71, the outlet end of the first check 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 in sequence, and also enters the high-pressure liquid pipe 7; after the two refrigerant liquids are mixed in the high-pressure liquid pipe 7, they pass 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 the first low-pressure gas pipe 6 in sequence, enter the main compression mechanism 1 and are compressed again, and a cycle is completed.

[0203] (2) Heating and defrosting function in winter

[0204] In this function, the main compression mechanism 1 works normally. One group of first heat exchangers 3 that do not need to be defrosted is still an evaporator to absorb heat from the outdoor air; the other group of first heat exchangers 3 that need to be defrosted is converted into a condenser for defrosting; the heater 2 still provides heat to the user; that is, one group of first heat exchangers 3 is used to absorb heat from the outdoor air, and the absorbed heat and the work consumed by the compressor are used together for heating the user and defrosting of the other group of first heat exchangers 3.

[0205] During operation, the first four-way valve 50 matched with the group of first heat exchangers 3 that need to be defrosted needs to be switched, and the communication mode of the first four-way valve 50 after switching is: the high-pressure node 51 of the first four-way valve 50 is connected with the first reversing node 52, and the low-pressure node 53 of the first four-way valve 50 is connected with the second reversing node 54. During defrosting, the first throttling mechanism 4 matched with the group of first heat exchangers 3 that need to be defrosted controls the amount of refrigerant gas used for defrosting by setting the opening.

[0206] Its working process is as follows: when working, the low-pressure refrigerant gas from the first low-pressure gas pipe 6 enters the main compression mechanism 1 to be compressed, and after the refrigerant is discharged from the outlet end of the main compression mechanism 1, it is divided into two paths; the first path 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 in sequence, and enters the high-pressure liquid pipe 7; the second path enters the high-pressure gas pipe 5 and is divided into the third path, which accounts for the vast majority, and the fourth path, which accounts for a small part; the third path passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 that needs to be defrosted, the first four-way valve 51 matched with the first heat exchanger 3 that needs to be defrosted, and the high-pressure node 52 of the first four-way valve 50 matched with the first heat exchanger 3 that needs to be defrosted in sequence. The first reversing node 52 of the four-way valve 50, the first heat exchanger 3 that needs to be defrosted, and the first throttling mechanism 4 matched with the first heat exchanger 3 that needs to be defrosted also enter the high-pressure liquid pipe 7; the fourth refrigerant sequentially passes through the high-pressure node 51 of the first four-way valve 50 matched with the first heat exchanger 3 that 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 that does not need to be defrosted, the inlet end of the first one-way valve 71 matched with the first heat exchanger 3 that does not need to be defrosted, 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 、 The outlet end of the heater 2 also enters the high-pressure liquid pipe 7; after the first, third and fourth refrigerants are mixed in the high-pressure liquid pipe 7, they pass through the first throttling mechanism 4 matched with the first heat exchanger 3 that does not need to be defrosted, the first heat exchanger 3 that does not need to be defrosted, the first reversing node 52 of the first four-way valve 50 matched with the first heat exchanger 3 that does not need to be defrosted, and the low-pressure node 53 of the first four-way valve 50 matched with the first heat exchanger 3 that does not need to be defrosted, and return to the first low-pressure gas pipe 6; enter the main compression mechanism 1 again to be compressed, and thus complete a cycle.

[0207] In all the above embodiments of the present invention, any one of the first one-way valve 71, the second one-way valve 72 and the third one-way valve 73 can be replaced by any one of a solenoid valve, a throttling mechanism with a shut-off function (for example, an electronic expansion valve) or a flow regulating mechanism.

[0208] In all the above-mentioned embodiments of the present invention, any one or both of the main compression mechanism 1 and the auxiliary compression mechanism 8 can adopt any one of the following compressors: scroll compressor, screw compressor, rolling rotor compressor, vane compressor, rotary vane compressor, centrifugal compressor, digital scroll compressor, magnetic levitation compressor; any one or both of the main compression mechanism 1 and the auxiliary compression mechanism 8 can also be a variable capacity compressor (for example: variable frequency compressor, digital scroll compressor), or a fixed speed compressor.

[0209] In all the above-mentioned embodiments of the present invention, the main compression mechanism 1 and the auxiliary compression mechanism 8 can also be a compressor group composed of at least two variable capacity compressors, or a compressor group composed of at least two constant speed compressors; in addition, the main compression mechanism 1 and the auxiliary compression mechanism 8 can also be a compressor group composed of at least one variable capacity compressor and at least one constant speed compressor.

[0210] In all the above embodiments of the present invention, any one of the first heat exchanger 3 and the second heat exchanger 9 can be a refrigerant-air heat exchanger, a refrigerant-water heat exchanger or other types of heat exchangers; when used as a refrigerant-water heat exchanger, any one of a volumetric heat exchanger, a plate heat exchanger, a shell and tube heat exchanger or a sleeve heat exchanger can be used. When any one of the first heat exchanger 3 and the second heat exchanger 9 is used as a refrigerant-air heat exchanger, a finned heat exchanger is usually used, and the fins of the finned heat exchanger are generally made of aluminum or aluminum alloy, and copper is also used in some special occasions.

[0211] In all the above embodiments of the present invention, one of the first throttling mechanism 4 and the second throttling mechanism 10, or even all of the throttling mechanisms can be replaced by a throttling mechanism with a shutoff function (eg, an electronic expansion valve).

[0212] In all the above embodiments of the present 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); Its characteristics are: 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 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 invention is characterized in that: 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); wherein: 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 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.

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); Its characteristics are: 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 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.

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); 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; 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); its characteristics are: 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 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 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 characteristics are: 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); 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.

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); Its characteristics are: 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 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.

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