Dual-stage compression multi-cycle PVT-air source multi-connected heat pump air-conditioning system for defrosting of outdoor heat source

Abstract

The present invention belongs to the technical field of solar heat pumps, and proposes a two-stage compression multi-cycle PVT-air source multi-connected heat pump air-conditioning system for defrosting of outdoor heat sources, including a low-pressure compressor, a high-pressure compressor, an outdoor fin heat exchanger, a PVT module, a throttle valve, an intermediate cooler, a stop valve, a check valve, a four-way reversing valve, an indoor heat exchanger, and an inverter. The two-stage compression multi-cycle PVT-air source multi-connected heat pump air-conditioning system for defrosting of outdoor heat sources provided by the present invention can operate throughout the year in six cycles, namely single-stage compression PVT heating, two-stage compression PVT heating, single-stage compression air source heating, two-stage compression air source heating, single-stage compression air source refrigeration, and defrosting cycle of the outdoor fin heat exchanger. When continuous operation of the outdoor fin heat exchanger requires defrosting in the single-stage or two-stage compression air source heating cycle, defrosting is carried out in a defrosting cycle that does not extract heat from the indoor environment. The heat pump air-conditioning system has strong environmental adaptability, high heating efficiency, high equipment utilization rate, and high photovoltaic cell power generation efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of solar heat pumps, and particularly relates to a two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioner system for defrosting an outdoor heat source. Background Art

[0002] In the Photovoltaic-thermal (PVT) technology, while the heat exchange medium takes away the waste heat generated by the photovoltaic module for utilization, the working temperature of the photovoltaic module is reduced and the photovoltaic power generation efficiency is improved. The PVT heat pump system is a combination of heat pump technology and PVT technology, which can simultaneously improve the heating efficiency of the heat pump cycle and the power generation efficiency of the photovoltaic cell, and output heat energy and electric energy on one system. Combining the air source heat pump cycle with the PVT heat pump cycle can form a PVT-air source heat pump system. Such a system overcomes the defects of both to a certain extent, achieves the complementary advantages of the two heat sources, and has high engineering application value. The existing PVT-air source heat pump systems have the following two deficiencies:

[0003] First, the operating conditions change violently, while the operating cycle mode is single. On the evaporation side of the heat pump system, the environmental temperature changes due to the rotation of seasons and the alternation of day and night. Especially, the large change in the heat dissipation of the photovoltaic cell caused by the change in the light intensity in the early morning and evening of the day and the heating effect on the evaporator cause a large change in the evaporation pressure of the system. The existing PVT-air source heat pump systems usually adopt a single-stage compression cycle, which is not suitable for operating under variable working conditions with violently changing evaporation pressure caused by the rotation of seasons and the alternation of day and night.

[0004] Second, the defrosting efficiency of the finned evaporator is low, and the utilization rate of the heat exchanger equipment is low. When the air source heat pump system operates in winter, due to the low outdoor air temperature, frost is likely to form on the surface of the outdoor evaporator, affecting the system performance. Solar energy can provide a high heat source during the day. The PVT-air source heat pump system combined with the air source heat pump system can greatly increase the evaporator temperature due to the heat dissipation of the photovoltaic cell under light, and can prevent the evaporator from frosting to a certain extent. However, on cloudy and rainy days without light or at night with low temperature, the PVT-air source heat pump system needs to switch to the air source outdoor finned heat exchanger for heat extraction. At this time, the PVT-air source heat pump system is the same as the ordinary air source heat pump system, and the outdoor finned heat exchanger will still frost. For this, there are mainly two existing defrosting methods: reverse cycle defrosting and energy storage defrosting. Reverse cycle defrosting extracts heat from the indoor heat exchanger, bringing a large temperature fluctuation to the indoor environment and switching the refrigerant flow direction, which brings a large impact to the system. Energy storage defrosting requires an additional energy storage heat exchanger in the system. At present, the energy storage heat exchanger is limited by problems such as energy storage materials and structures, and cannot be widely promoted. In addition, on cloudy and rainy days or at night, when the existing PVT-air source heat pump system defrosts, no matter which of the above two defrosting methods is used, the PVT components will be idle during defrosting. Summary of the Invention

[0005] The object of the present invention is to provide a two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioner system for defrosting an outdoor heat source, which can realize the mutual switching between single-stage compression and two-stage compression cycles during heating and can also avoid taking heat from the indoor environment during defrosting.

[0006] The technical solution adopted to achieve the object of the present invention is: a two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioner system for defrosting an outdoor heat source, including a low-pressure compressor 1-1, a high-pressure compressor 1-2, an outdoor fin heat exchanger 2, a PVT component 3, a throttle valve, an intermediate cooler 5, a stop valve, a check valve, a four-way reversing valve, an indoor heat exchanger 9, and an inverter 10;

[0007] The PVT component 3 is connected to the inverter 10; one end of the PVT component 3 branches, one branch passes through the fifth stop valve 7-5 and is connected to the second interface of the first four-way reversing valve 8-1, and the other branch passes through the second check valve 6-2 and is connected to the first interface of the second four-way reversing valve 8-2; the first interface of the first four-way reversing valve 8-1 is connected to the suction port of the low-pressure compressor 1-1, and the discharge port of the low-pressure compressor 1-1 is connected to the third interface of a four-way reversing valve 8-1; the fourth interface of the first four-way reversing valve 8-1 is respectively connected to the third interface of the intermediate cooler 5, the suction port of the high-pressure compressor 1-2, and the outlet of the first check valve 6-1; the discharge port of the high-pressure compressor 1-2 is connected to the second interface of the second four-way reversing valve 8-2; the third interface of the second four-way reversing valve 8-2 is divided into two branches after passing through the indoor heat exchanger 9 and the fourth throttle valve 4-4 in sequence. One branch is connected to the fourth interface of the intermediate cooler 5, and the other branch passes through the third stop valve 7-3 and the third throttle valve 4-3 in sequence and is connected to the second interface of the intermediate cooler 5; the fourth interface of the second four-way reversing valve 8-2 is connected to the inlet of the first check valve 6-1; the first interface of the intermediate cooler 5 is divided into two pipelines after passing through the fourth stop valve 7-4. One pipeline passes through the second stop valve 7-2 and the second throttle valve 4-2 in sequence and is connected to the other end of the PVT component 3; the other pipeline passes through the first stop valve 7-1 and the first throttle valve 4-1 in sequence and is connected to one end of the outdoor fin heat exchanger 2, and the other end of the outdoor fin heat exchanger 2 is connected to the pipeline between the fifth stop valve 7-5 and the second interface of the first four-way reversing valve 8-1.

[0008] The two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioner system for defrosting an outdoor heat source operates in six cycles: single-stage compression PVT heating cycle, single-stage compression air source heating cycle, two-stage compression PVT heating cycle, two-stage compression air source heating cycle, outdoor fin heat exchanger defrosting cycle, and single-stage compression air source refrigeration cycle.

[0009] When the dual-stage compression multi-cycle PVT-air source multi-connected unit heat pump air-conditioning system for outdoor heat source defrosting operates in a single-stage compression PVT heating cycle, the first cut-off valve 7-1, the third cut-off valve 7-3, and the fifth cut-off valve 7-5 are closed, the second cut-off valve 7-2 and the fourth cut-off valve 7-4 are opened, the first port of the second four-way reversing valve 8-2 is communicated with the fourth port of the second four-way reversing valve 8-2, the second port of the second four-way reversing valve 8-2 is communicated with the third port of the second four-way reversing valve 8-2, the low-pressure compressor 1-1 stops operating, the high-pressure compressor 1-2 starts operating, and the photovoltaic cells in the PVT module 3 generate electricity under sunlight irradiation and are adjusted by the inverter 10 into electricity that can be used by users.

[0010] When the dual-stage compression multi-cycle PVT-air source multi-connected unit heat pump air-conditioning system for outdoor heat source defrosting operates in a single-stage compression air source heating cycle, the first cut-off valve 7-1, the fourth cut-off valve 7-4, and the fifth cut-off valve 7-5 are opened, the second cut-off valve 7-2 and the third cut-off valve 7-3 are closed, the first port of the second four-way reversing valve 8-2 is communicated with the fourth port of the second four-way reversing valve 8-2, the second port of the second four-way reversing valve 8-2 is communicated with the third port of the second four-way reversing valve 8-2, the low-pressure compressor 1-1 stops operating, the high-pressure compressor 1-2 starts operating, and the photovoltaic cells in the PVT module 3 generate electricity under sunlight irradiation and are adjusted by the inverter 10 into electricity that can be used by users.

[0011] When the dual-stage compression multi-cycle PVT-air source multi-connected unit heat pump air-conditioning system for outdoor heat source defrosting operates in a dual-stage compression PVT heating cycle, the first cut-off valve 7-1 is closed, the second cut-off valve 7-2, the third cut-off valve 7-3, the fourth cut-off valve 7-4, and the fifth cut-off valve 7-5 are opened, the first port of the first four-way reversing valve 8-1 is communicated with the second port of the first four-way reversing valve 8-1, the third port of the first four-way reversing valve 8-1 is communicated with the fourth port of the first four-way reversing valve 8-1, the first port of the second four-way reversing valve 8-2 is communicated with the fourth port of the second four-way reversing valve 8-2, the second port of the second four-way reversing valve 8-2 is communicated with the third port of the second four-way reversing valve 8-2, both the low-pressure compressor 1-1 and the high-pressure compressor 1-2 start operating, and the photovoltaic cells in the PVT module 3 generate electricity under sunlight irradiation and are adjusted by the inverter 10 into electricity that can be used by users.

[0012] When the dual-stage compression multi-cycle PVT-air source multi-connected unit heat pump air conditioner system for outdoor heat source defrosting operates in the dual-stage compression air source heating cycle, open the first shut-off valve 7-1, the third shut-off valve 7-3, and the fourth shut-off valve 7-4, close the second shut-off valve 7-2 and the fifth shut-off valve 7-5. The first interface of the first four-way reversing valve 8-1 is communicated with the second interface of the first four-way reversing valve 8-1, the third interface of the first four-way reversing valve 8-1 is communicated with the fourth interface of the first four-way reversing valve 8-1, the second interface of the second four-way reversing valve 8-2 is communicated with the third interface of the second four-way reversing valve 8-2, and the first interface of the second four-way reversing valve 8-2 is communicated with the fourth interface of the second four-way reversing valve 8-2. The low-pressure compressor 1-1 and the high-pressure compressor 1-2 are both turned on. The photovoltaic cells in the PVT module 3 generate electricity under sunlight irradiation and are adjusted by the inverter 10 to become electricity that can be used by users.

[0013] When the dual-stage compression multi-cycle PVT-air source multi-connected unit heat pump air conditioner system for outdoor heat source defrosting operates in the outdoor fin heat exchanger defrosting cycle, open the first shut-off valve 7-1 and the second shut-off valve 7-2, close the third shut-off valve 7-3, the fourth shut-off valve 7-4, and the fifth shut-off valve 7-5. The first interface of the first four-way reversing valve 8-1 is communicated with the fourth interface of the first four-way reversing valve 8-1, the second interface of the first four-way reversing valve 8-1 is communicated with the third interface of the first four-way reversing valve 8-1, the first interface of the second four-way reversing valve 8-2 is communicated with the fourth interface of the second four-way reversing valve 8-2, and the second interface of the second four-way reversing valve 8-2 is communicated with the third interface of the second four-way reversing valve 8-2. The low-pressure compressor 1-1 is turned on, and the high-pressure compressor 1-2 is turned off. The opening of the first throttle valve 4-1 is adjusted to the maximum. The photovoltaic cells in the PVT module 3 generate electricity under sunlight irradiation and are adjusted by the inverter 10 to become electricity that can be used by users.

[0014] When the dual-stage compression multi-cycle PVT-air source multi-connected unit heat pump air conditioner system for outdoor heat source defrosting operates in the single-stage compression air source refrigeration cycle, open the first shut-off valve 7-1 and the fourth shut-off valve 7-4, close the second shut-off valve 7-2, the third shut-off valve 7-3, and the fifth shut-off valve 7-5. The first interface of the first four-way reversing valve 8-1 is communicated with the fourth interface of the first four-way reversing valve 8-1, the second interface of the first four-way reversing valve 8-1 is communicated with the third interface of the first four-way reversing valve 8-1, the first interface of the second four-way reversing valve 8-2 is communicated with the second interface of the second four-way reversing valve 8-2, and the third interface of the second four-way reversing valve 8-2 is communicated with the fourth interface of the second four-way reversing valve 8-2. The low-pressure compressor 1-1 is turned on, and the high-pressure compressor 1-2 is turned off. The opening of the first throttle valve 4-1 is adjusted to the maximum.

[0015] The low-pressure compressor 1-1 and the high-pressure compressor 1-2 are any one of a scroll compressor, a rotary compressor, a screw compressor, and a piston compressor; the throttle valve is an electronic expansion valve, a thermostatic expansion valve, a capillary tube, or an orifice throttling device; the stop valve is a solenoid valve, a manual valve, or a ball valve.

[0016] During the day in the transition season when the ambient temperature is relatively high and the sunlight is strong, the dual-stage compression multi-cycle PVT-air source multi-connected unit heat pump air conditioner system for outdoor heat source defrosting of the present invention operates in a single-stage compression PVT heating cycle, and the operating schematic diagram is as Figure 2 shown.

[0017] During the day in the transition season when the ambient temperature is relatively high and the sunlight is weak or at night without sunlight, the dual-stage compression multi-cycle PVT-air source multi-connected unit heat pump air conditioner system for outdoor heat source defrosting of the present invention operates in a single-stage compression air source heating cycle, and the operating schematic diagram is as Figure 3 shown.

[0018] During the day in the cold winter when the ambient temperature is relatively low and the sunlight is strong, the dual-stage compression multi-cycle PVT-air source multi-connected unit heat pump air conditioner system for outdoor heat source defrosting of the present invention operates in a dual-stage compression PVT heating cycle, and the operating schematic diagram is as Figure 4 shown.

[0019] When the ambient temperature is relatively low or the hot water temperature is relatively high, during the day with low sunlight or at night without sunlight, the dual-stage compression multi-cycle PVT-air source multi-connected unit heat pump air conditioner system for outdoor heat source defrosting of the present invention operates in a dual-stage compression air source heating cycle, and the operating schematic diagram is as Figure 5 shown.

[0020] During the day with low sunlight or at night without sunlight, the dual-stage compression multi-cycle PVT-air source multi-connected unit heat pump air conditioner system for outdoor heat source defrosting of the present invention continuously operates in a single-stage compression air source heating cycle or a dual-stage compression air source heating cycle for a period of time. When the outdoor fin heat exchanger needs to be defrosted, the dual-stage compression multi-cycle PVT-air source multi-connected unit heat pump air conditioner system for outdoor heat source defrosting of the present invention operates in an outdoor fin heat exchanger defrosting cycle, and the operating schematic diagram is as Figure 6 shown.

[0021] In the hot summer, the dual-stage compression multi-cycle PVT-air source multi-connected unit heat pump air conditioner system for outdoor heat source defrosting of the present invention operates in a single-stage compression air source refrigeration cycle, and the operating schematic diagram is as Figure 7 shown.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. The dual-stage compression multi-cycle PVT-air source multi-connected heat pump air-conditioning system for outdoor heat source defrosting of the present invention can operate in a single-stage compression PVT heating cycle or a single-stage compression air source heating cycle in a medium-temperature outdoor environment during the transitional season, and can also operate in a dual-stage compression PVT heating cycle or a dual-stage compression air source heating cycle in a low-temperature outdoor environment in winter. It can also operate in a single-stage compression air source refrigeration cycle in a hot summer season. The heat pump multi-connected system of the present invention can flexibly switch between various heating and refrigeration cycles, has strong environmental adaptability and high efficiency;

[0024] 2. When the dual-stage compression multi-cycle PVT-air source multi-connected heat pump air-conditioning system for outdoor heat source defrosting of the present invention has a defrosting requirement after long-term operation in a single-stage compression air source heating cycle or a dual-stage compression air source heating cycle, it can obtain heat from the idle PVT components at the same outdoor environmental temperature instead of extracting heat from the indoor environment. The indoor comfort is relatively high, the defrosting efficiency of the outdoor fin heat exchanger is high, the speed is fast, the pressure change of the multi-connected system before and after defrosting is relatively slow, the impact on the system is small, and the system stability is good. By using the idle PVT components, the equipment utilization rate is high;

[0025] 3. The dual-stage compression multi-cycle PVT-air source multi-connected heat pump air-conditioning system for outdoor heat source defrosting of the present invention operates in a dual-stage compression PVT heating cycle in a low-temperature outdoor environment with sufficient sunlight. The temperature of the PVT components is lower, and the power generation efficiency of the photovoltaic cells is relatively high. Description of the Drawings

[0026] Figure 1 The figure shows a schematic diagram of the dual-stage compression multi-cycle PVT-air source multi-connected heat pump air-conditioning system for outdoor heat source defrosting of the present invention;

[0027] In the figure: 1-1, low-pressure compressor; 1-2, high-pressure compressor; 2, outdoor fin heat exchanger; 3, PVT components; 4-1, first throttle valve; 4-2, second throttle valve; 4-3, third throttle valve; 4-4, fourth throttle valve; 5, intermediate cooler; 6-1, fourth stop valve; 6-2, second check valve; 7-1, first stop valve; 7-2, second stop valve; 7-3, third stop valve; 7-4, fourth stop valve; 7-5, fifth stop valve; 8-1, first four-way reversing valve; 8-2, second four-way reversing valve; 9, indoor heat exchanger; 10, inverter.

[0028] Figure 2 The figure shows a schematic diagram of the operation principle of the dual-stage compression multi-cycle PVT-air source multi-connected heat pump air-conditioning system for outdoor heat source defrosting of the present invention in a single-stage compression PVT heating cycle;

[0029] Figure 3The following shows the schematic diagram of the single-stage compression air source heating cycle operation of the two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioner system for outdoor heat source defrosting of the present invention;

[0030] Figure 4 The following shows the schematic diagram of the two-stage compression PVT heating cycle operation of the two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioner system for outdoor heat source defrosting of the present invention;

[0031] Figure 5 The following shows the schematic diagram of the two-stage compression air source heating cycle operation of the two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioner system for outdoor heat source defrosting of the present invention;

[0032] Figure 6 The following shows the schematic diagram of the defrosting cycle operation of the outdoor fin heat exchanger of the two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioner system for outdoor heat source defrosting of the present invention;

[0033] Figure 7 The following shows the schematic diagram of the single-stage compression air source refrigeration cycle operation of the two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioner system for outdoor heat source defrosting of the present invention;

[0034] Figure 8 The following shows the schematic diagram of the intermediate cooler interface in the two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioner system for outdoor heat source defrosting of the present invention;

[0035] In the figure: 5a, the first interface of the intermediate cooler; 5b, the second interface of the intermediate cooler; 5c, the third interface of the intermediate cooler; 5d, the fourth interface of the intermediate cooler.

[0036] Figure 9 The following shows the schematic diagram of the first four-way reversing valve interface in the two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioner system for outdoor heat source defrosting of the present invention;

[0037] In the figure: 8a, the first interface of the first four-way reversing valve; 8b, the second interface of the first four-way reversing valve; 8c, the third interface of the first four-way reversing valve; 8d, the fourth interface of the first four-way reversing valve. Detailed implementation manners

[0038] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "high pressure", "medium pressure", and "low pressure" should be understood in a broad sense, referring to the relative pressure values in the same refrigerant loop. For example, in the two-stage compression heating cycle, the pressure between the exhaust port of the high-pressure compressor and the inlet of the fourth throttle valve is high pressure, the pressure between the suction port of the high-pressure compressor, the exhaust port of the low-pressure compressor and the outlet of the third throttle valve is medium pressure, and the pressure between the suction port of the low-pressure compressor and the outlet of the first throttle valve or the second throttle valve is low pressure.

[0039] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0040] The schematic diagram of the two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioner system for defrosting of the outdoor heat source of the present invention is as Figure 1 shown. The system includes a low-pressure compressor 1-1, a high-pressure compressor 1-2, an outdoor fin heat exchanger 2, a PVT module 3, a first throttle valve 4-1, a second throttle valve 4-2, a third throttle valve 4-3, a fourth throttle valve 4-4, an intercooler 5, a fourth stop valve 7-4, a second check valve 6-2, a first stop valve 7-1, a second stop valve 7-2, a third stop valve 7-3, a fifth stop valve 7-5, a first four-way reversing valve 8-1, a second four-way reversing valve 8-2, an indoor heat exchanger 9, and an inverter 10; the exhaust port of the low-pressure compressor 1-1 is connected to the third port of the first four-way reversing valve 8-1, the suction port of the low-pressure compressor 1-1 is connected to the first port of the first four-way reversing valve 8-1, the second port of the first four-way reversing valve 8-1 is connected to one end of the fifth stop valve 7-5 and one end of the outdoor fin heat exchanger 2, the fourth port of the first four-way reversing valve 8-1 is connected to the outlet of the fourth stop valve 7-4, the third port of the intercooler 5, and the suction port of the high-pressure compressor 1-2; the exhaust port of the high-pressure compressor 1-2 is connected to the second port of the second four-way reversing valve 8-2, the first port of the second four-way reversing valve 8-2 is connected to the outlet of the second check valve 6-2, the third port of the second four-way reversing valve 8-2 is connected to one end of the fourth throttle valve 4-4 through the indoor heat exchanger 9, and the first port of the second four-way reversing valve 8-2 is connected to the inlet of the fourth stop valve 7-4; the fourth throttle valve 4-4 is connected to the fourth port of the intercooler 5 and one end of the third stop valve 7-3, the other end of the third stop valve 7-3 is connected to the second port of the intercooler 5 through the third throttle valve 4-3, the first port of the intercooler 5 is connected to one end of the first stop valve 7-1 and one end of the second stop valve 7-2 through the fourth stop valve 7-4, the other end of the first stop valve 7-1 is connected to the other end of the outdoor fin heat exchanger 2 through the first throttle valve 4-1, the other end of the second stop valve 7-2 is connected to one end of the PVT module through the second throttle valve 4-2, and the other end of the PVT module 3 is connected to the inlet of the second check valve 6-2 and the other end of the fifth stop valve 7-5; the PVT module 3 is connected to the inverter 10.

[0041] The two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for defrosting of outdoor heat sources of the present invention realizes six cycle operations of single-stage compression PVT heating, two-stage compression PVT heating, single-stage compression air source heating, two-stage compression air source heating, defrosting of outdoor finned heat exchangers, and single-stage compression air source refrigeration according to ambient temperature, light intensity, heating, refrigeration, and defrosting requirements.

[0042] During the day in the transitional season when the ambient temperature is relatively high and the light is strong, the two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for defrosting of outdoor heat sources of the present invention operates in a single-stage compression PVT heating cycle, and the operating schematic diagram is as Figure 2 shown. Close the first stop valve 7-1, the third stop valve 7-3, and the fifth stop valve 7-5, open the second stop valve 7-2 and the fourth stop valve 7-4. The first interface of the second four-way reversing valve 8-2 is communicated with the fourth interface of the second four-way reversing valve 8-2, and the second interface of the second four-way reversing valve 8-2 is communicated with the third interface of the second four-way reversing valve 8-2. The low-pressure compressor 1-1 stops running, and the high-pressure compressor 1-2 starts running. The photovoltaic cells in the PVT module 3 generate electricity under sunlight irradiation and are adjusted by the inverter 10 to become electricity that can be used by users.

[0043] The refrigerant thermodynamic process is as follows: The PVT module 3 outputs low-pressure and low-temperature refrigerant gas at one end, passes through the second check valve 6-2 to the suction port of the high-pressure compressor 1-2; the low-pressure and low-temperature refrigerant gas is compressed and boosted by the high-pressure compressor 1-2 to become high-pressure and high-temperature superheated gas, and successively passes through the second interface of the second four-way reversing valve 8-2 and the third interface of the second four-way reversing valve 8-2 and enters the indoor heat exchanger 9; the high-pressure and high-temperature superheated gas is condensed by indoor air in the indoor heat exchanger 9 to become high-pressure liquid, and at the same time, heating occurs indoors. The high-pressure liquid flowing out of the indoor heat exchanger 9 is expanded and depressurized by the fourth throttle valve 4-4 to become a medium-pressure gas-liquid mixture, and successively passes through the fourth interface of the intermediate cooler 5, the first interface of the intermediate cooler 5, the fourth stop valve 7-4, and the second stop valve 7-2 and enters the second throttle valve 4-2. The medium-pressure gas-liquid mixture is expanded and depressurized by the second throttle valve 4-2 and then becomes low-pressure gas-liquid mixed refrigerant and enters the other end of the PVT module 3. The low-pressure gas-liquid mixed refrigerant absorbs the heat of the photovoltaic cells in the PVT module 3 and then becomes low-pressure and low-temperature refrigerant gas and is output from one end of the PVT module 3, completing the refrigeration cycle.

[0044] During the day in the transitional season when the ambient temperature is relatively high and the light is weak or at night without light, the two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for defrosting of outdoor heat sources of the present invention operates in a single-stage compression air source heating cycle, and the operating schematic diagram is as Figure 3As shown in the figure. Open the first stop valve 7-1, the fourth stop valve 7-4, and the fifth stop valve 7-5, and close the second stop valve 7-2 and the third stop valve 7-3. The first interface of the second four-way reversing valve 8-2 is communicated with the fourth interface of the second four-way reversing valve 8-2, and the second interface of the second four-way reversing valve 8-2 is communicated with the third interface of the second four-way reversing valve 8-2. The low-pressure compressor 1-1 stops running, and the high-pressure compressor 1-2 starts running; the photovoltaic cells in the PVT module 3 generate electricity under sunlight irradiation and are adjusted by the inverter 10 into electricity that can be used by users.

[0045] The refrigerant thermodynamic process is as follows: The low-pressure and low-temperature refrigerant gas output from the other end of the outdoor fin heat exchanger 2 passes through the fifth stop valve 7-5, the second check valve 6-2, the first interface of the second four-way reversing valve 8-2, the fourth interface of the second four-way reversing valve 8-2, and the first check valve 6-1 in sequence and is connected to the suction port of the high-pressure compressor 1-2; the low-pressure and low-temperature refrigerant gas is compressed and boosted by the high-pressure compressor 1-2 into a high-pressure and high-temperature superheated gas, and passes through the second interface of the second four-way reversing valve 8-2 and the third interface of the second four-way reversing valve 8-2 in sequence and enters the indoor heat exchanger 9; the high-pressure and high-temperature superheated gas is condensed by the indoor air into a high-pressure liquid in the indoor heat exchanger 9, and at the same time, a heating phenomenon occurs indoors. The high-pressure liquid flowing out of the indoor heat exchanger 9 is expanded and depressurized by the fourth throttle valve 4-4 into a medium-pressure gas-liquid mixture, and passes through the fourth interface of the intermediate cooler 5, the first interface of the intermediate cooler 5, the fourth stop valve 7-4, and the first stop valve 7-1 in sequence and enters the first throttle valve 4-1. The medium-pressure gas-liquid mixture is expanded and depressurized by the first throttle valve 4-1 into a low-pressure gas-liquid mixed refrigerant and enters one end of the outdoor fin heat exchanger 2. The low-pressure gas-liquid mixed refrigerant absorbs heat from the air in the outdoor fin heat exchanger 2 and becomes a low-pressure and low-temperature refrigerant gas, which is output from the other end of the outdoor fin heat exchanger 2 to complete the refrigeration cycle.

[0046] In cold winter with low ambient temperature and strong sunlight during the day, the dual-stage compression multi-cycle PVT-air source multi-connected unit heat pump air conditioner system for outdoor heat source defrosting of the present invention operates in a dual-stage compression PVT heating cycle, and the operating schematic diagram is as Figure 4 As shown in the figure. Close the first stop valve 7-1, open the second stop valve 7-2, the third stop valve 7-3, the fourth stop valve 7-4, and the fifth stop valve 7-5. The first interface of the first four-way reversing valve 8-1 is communicated with the second interface of the first four-way reversing valve 8-1, the third interface of the first four-way reversing valve 8-1 is communicated with the fourth interface of the first four-way reversing valve 8-1, the first interface of the second four-way reversing valve 8-2 is communicated with the fourth interface of the second four-way reversing valve 8-2, and the second interface of the second four-way reversing valve 8-2 is communicated with the third interface of the second four-way reversing valve 8-2. Both the low-pressure compressor 1-1 and the high-pressure compressor 1-2 start running. The photovoltaic cells in the PVT module 3 generate electricity under sunlight irradiation and are adjusted by the inverter 10 into electricity that can be used by users.

[0047] The thermodynamic process of the refrigerant is as follows: The low-pressure and low-temperature refrigerant gas output from one end of the PVT module 3 passes through the fifth stop valve 7-5, the second interface of the first four-way reversing valve 8-1, and the first interface of the first four-way reversing valve 8-1 in sequence and is transmitted to the suction port of the low-pressure compressor 1-1; the low-pressure and low-temperature refrigerant gas is compressed and pressurized by the low-pressure compressor 1-1 to become a medium-pressure superheated gas, and passes through the third interface of the first four-way reversing valve 8-1 and the fourth interface of the first four-way reversing valve 8-1 in sequence. The medium-pressure superheated gas is mixed with the medium-pressure gas flowing out of the third interface of the intermediate cooler 5 and then input to the high-pressure compressor 1-2. After being compressed and pressurized by the high-pressure compressor 1-2, it becomes a high-temperature and high-pressure superheated gas and passes through the second interface of the second four-way reversing valve 8-2 and the third interface of the second four-way reversing valve 8-2 in sequence, and enters the indoor heat exchanger 9. The high-temperature and high-pressure superheated gas is condensed by the indoor air in the indoor heat exchanger 9 to become a high-pressure liquid. At the same time, heating occurs indoors. The high-pressure liquid flowing out of the indoor heat exchanger 9 is expanded and depressurized by the fourth throttle valve 4-4 to become a gas-liquid mixture with a slightly lower pressure; the gas-liquid mixture is divided into main and branch paths; a part of the gas-liquid mixture branch passes through the third stop valve 7-3 and enters the third throttle valve 4-3. After being expanded and depressurized, it becomes a medium-pressure gas-liquid mixture and enters the second interface of the intermediate cooler 5. The liquid part of the medium-pressure gas-liquid mixture evaporates and absorbs part of the heat of the main path in the intermediate cooler 5 to become a medium-pressure gas. The medium-pressure gas flows out of the third interface of the intermediate cooler 5 and is mixed with the medium-pressure superheated gas discharged from the low-pressure compressor 1-1; the main part of the gas-liquid mixture enters the fourth interface of the intermediate cooler 5. After the gas-liquid mixture with a low pressure is cooled, it becomes a high-pressure liquid with a certain degree of subcooling and flows out of the first interface of the intermediate cooler 5. Then, it passes through the fourth stop valve 7-4 and the second stop valve 7-2 in sequence and enters the second throttle valve 4-2. After being expanded and depressurized by the second throttle valve 4-2, it becomes a low-pressure gas-liquid mixed refrigerant and enters the other end of the PVT module 3. The low-pressure gas-liquid mixed refrigerant absorbs the heat of the photovoltaic cell in the PVT module 3 and becomes a low-pressure and low-temperature refrigerant gas, which is output from one end of the PVT module 3, completing the refrigeration cycle.

[0048] When the ambient temperature is relatively low or the hot water temperature is relatively high, during the day with low sunlight or at night without sunlight, the dual-stage compression multi-cycle PVT-air source multi-connected unit heat pump air conditioner system for defrosting of the outdoor heat source of the present invention operates in a dual-stage compression air source heating cycle, and the operation schematic diagram is as Figure 5As shown in the figure. Open the first shut-off valve 7-1, the third shut-off valve 7-3, and the fourth shut-off valve 7-4, and close the second shut-off valve 7-2 and the fifth shut-off valve 7-5. The first interface of the first four-way reversing valve 8-1 is connected to the second interface of the first four-way reversing valve 8-1, the third interface of the first four-way reversing valve 8-1 is connected to the fourth interface of the first four-way reversing valve 8-1, the second interface of the second four-way reversing valve 8-2 is connected to the third interface of the second four-way reversing valve 8-2, and the first interface of the second four-way reversing valve 8-2 is connected to the fourth interface of the second four-way reversing valve 8-2. The low-pressure compressor 1-1 and the high-pressure compressor 1-2 are both started. The photovoltaic cells in the PVT module 3 generate electricity under sunlight irradiation and are adjusted by the inverter 10 to become electricity that can be used by users.

[0049] The refrigerant thermodynamic process is as follows: The low-pressure and low-temperature refrigerant gas output from the other end of the outdoor finned heat exchanger 2 passes through the second interface of the first four-way reversing valve 8-1 and the first interface of the first four-way reversing valve 8-1 to the suction port of the low-pressure compressor 1-1 in sequence; the low-pressure and low-temperature refrigerant gas is compressed and boosted by the low-pressure compressor 1-1 to become a medium-pressure superheated gas, passing through the third interface of the first four-way reversing valve 8-1 and the fourth interface of the first four-way reversing valve 8-1 in sequence. The medium-pressure superheated gas is mixed with the medium-pressure gas flowing out of the third interface of the intermediate cooler 5 and then input to the high-pressure compressor 1-2. After being compressed and boosted by the high-pressure compressor 1-2, it becomes a high-temperature and high-pressure superheated gas, passing through the second interface of the second four-way reversing valve 8-2 and the third interface of the second four-way reversing valve 8-2 in sequence and entering the indoor heat exchanger 9. The high-temperature and high-pressure superheated gas is condensed by the indoor air in the indoor heat exchanger 9 to become a high-pressure liquid. At the same time, heating occurs indoors. The high-pressure liquid flowing out of the indoor heat exchanger 9 is expanded and depressurized by the fourth throttle valve 4-4 to become a gas-liquid mixture with a slightly lower pressure, which is divided into main and branch paths; a part of the gas-liquid mixture branch passes through the third shut-off valve 7-3 and enters the third throttle valve 4-3. After being expanded and depressurized by the third throttle valve 4-3, it becomes a medium-pressure gas-liquid mixture and enters the second interface of the intermediate cooler 5. The liquid part of the gas-liquid mixture evaporates in the intermediate cooler 5 to absorb the heat of the main part of the gas-liquid mixture with a low liquid pressure and becomes a medium-pressure gas. The medium-pressure gas flows out of the third interface of the intermediate cooler 5 and is mixed with the medium-pressure superheated gas discharged from the low-pressure compressor 1-1; the main part of the gas-liquid mixture enters the fourth interface of the intermediate cooler 5, is cooled and then becomes a high-pressure liquid with a certain degree of subcooling and flows out from the first interface of the intermediate cooler 5, passing through the fourth shut-off valve 7-4 and the first shut-off valve 7-1 in sequence and entering the first throttle valve 4-1. After being expanded and depressurized by the first throttle valve 4-1, it becomes a low-pressure gas-liquid mixed refrigerant and enters one end of the outdoor finned heat exchanger 2. The low-pressure gas-liquid mixed refrigerant absorbs the heat in the outdoor air in the outdoor finned heat exchanger 2 and then becomes a low-pressure and low-temperature refrigerant gas and is output from the other end of the outdoor finned heat exchanger 2, completing the refrigeration cycle.

[0050] During low-light daytime or no-light nighttime, the dual-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for outdoor heat source defrosting of the present invention operates continuously for a period of time in a single-stage compression air source heating cycle or a dual-stage compression air source heating cycle. When the outdoor fin heat exchanger needs to be defrosted, the dual-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for outdoor heat source defrosting of the present invention operates in an outdoor fin heat exchanger defrosting cycle, and the operation schematic diagram is as Figure 6 shown. Open the first stop valve 7-1 and the second stop valve 7-2, close the third stop valve 7-3, the fourth stop valve 7-4, and the fifth stop valve 7-5. The first interface of the first four-way reversing valve 8-1 is communicated with the fourth interface of the first four-way reversing valve 8-1, the second interface of the first four-way reversing valve 8-1 is communicated with the third interface of the first four-way reversing valve 8-1, the first interface of the second four-way reversing valve 8-2 is communicated with the fourth interface of the second four-way reversing valve 8-2, and the second interface of the second four-way reversing valve 8-2 is communicated with the third interface of the second four-way reversing valve 8-2. Start the low-pressure compressor 1-1 and stop the high-pressure compressor 1-2, and adjust the opening of the first throttle valve 4-1 to the maximum; the photovoltaic cells in the PVT module 3 generate electricity under sunlight irradiation and are adjusted by the inverter 10 to become electricity that can be used by users.

[0051] The refrigerant thermodynamic process is as follows: The low-pressure and low-temperature refrigerant gas output from one end of the PVT module 3 passes through the second check valve 6-2, the first interface of the second four-way reversing valve 8-2, the fourth interface of the second four-way reversing valve 8-2, the first check valve 6-1, the fourth interface of the first four-way reversing valve 8-1, and the first interface of the first four-way reversing valve 8-1 to enter the suction port of the low-pressure compressor 1-1. The low-pressure and low-temperature refrigerant gas is compressed and boosted by the low-pressure compressor 1-1 to become a high-pressure and superheated gas, and then passes through the third interface of the first four-way reversing valve 8-1 and the second interface of the first four-way reversing valve 8-1 to enter the other end of the outdoor fin heat exchanger 2; the high-pressure and superheated gas heats the fins in the outdoor fin heat exchanger 2 to become a high-pressure liquid, and at the same time the frost layer on the fin surface melts due to heat. The high-pressure liquid flowing out from one end of the outdoor fin heat exchanger 2 passes through the first throttle valve 4-1, the first stop valve 7-1, and the second stop valve 7-2 to enter the second throttle valve 4-2. After the high-pressure liquid is expanded and depressurized by the second throttle valve 4-2, it becomes a low-pressure gas-liquid mixed refrigerant and enters the other end of the PVT module 3. The low-pressure gas-liquid mixed refrigerant absorbs the heat of the PVT module 3 and the outdoor air in the PVT module 3 and then becomes a low-pressure and low-temperature refrigerant gas and is output from one end of the PVT module 3 to complete the defrosting cycle.

[0052] During the hot summer, the dual-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for outdoor heat source defrosting of the present invention operates in a single-stage compression air source refrigeration cycle, and the operation schematic diagram is as Figure 7As shown in the figure. Open the first shut-off valve 7-1 and the fourth shut-off valve 7-4, and close the second shut-off valve 7-2, the third shut-off valve 7-3, and the fifth shut-off valve 7-5. The first interface of the first four-way reversing valve 8-1 is connected to the fourth interface of the first four-way reversing valve 8-1, the second interface of the first four-way reversing valve 8-1 is connected to the third interface of the first four-way reversing valve 8-1, the first interface of the second four-way reversing valve 8-2 is connected to the second interface of the second four-way reversing valve 8-2, and the third interface of the second four-way reversing valve 8-2 is connected to the fourth interface of the second four-way reversing valve 8-2. Start the low-pressure compressor 1-1 and stop the high-pressure compressor 1-2, and adjust the opening of the first throttle valve 4-1 to the maximum; the photovoltaic cells in the PVT module 3 generate electricity under sunlight irradiation and are adjusted by the inverter 10 to become electricity that can be used by users.

[0053] The refrigerant thermodynamic process is as follows: The low-pressure and low-temperature refrigerant gas output by the indoor heat exchanger 9 passes through the third interface of the second four-way reversing valve 8-2, the fourth interface of the second four-way reversing valve 8-2, the first check valve 6-1, the fourth interface of the first four-way reversing valve 8-1, and the first interface of the first four-way reversing valve 8-1 in sequence and enters the suction port of the low-pressure compressor 1-1. The low-pressure and low-temperature refrigerant gas is compressed and pressurized by the low-pressure compressor 1-1 to become a high-pressure and superheated gas, and then passes through the third interface of the first four-way reversing valve 8-1 and the second interface of the first four-way reversing valve 8-1 in sequence and enters the other end of the outdoor finned heat exchanger 2. The high-pressure and superheated gas is cooled by air in the outdoor finned heat exchanger 2 to become a high-pressure liquid. The high-pressure liquid passes through the first throttle valve 4-1, the first shut-off valve 7-1, the fourth shut-off valve 7-4, the first interface of the intercooler 5, and the fourth interface of the intercooler 5 in sequence and enters the fourth throttle valve 4-4. The high-pressure liquid expands and depressurizes through the fourth throttle valve 4-4 to become a low-pressure gas-liquid mixed refrigerant and enters the indoor heat exchanger 9. The low-pressure gas-liquid mixed refrigerant absorbs heat from the indoor air in the indoor heat exchanger 9 and then becomes a low-pressure and low-temperature refrigerant gas and is output, resulting in a refrigeration phenomenon indoors and completing the refrigeration cycle of the indoor heat exchanger 9.

[0054] The PVT module can be flat box type, tube plate type, blown plate type or flat plate type.

[0055] The compressor can be any one of scroll compressor, rotor compressor, screw compressor and piston compressor.

[0056] The low-temperature expansion valve, high-temperature expansion valve and precooling expansion valve are electronic expansion valve, thermostatic expansion valve, capillary tube or orifice throttling device.

[0057] As Figure 8 shown in the figure: The specific positions of the intercooler interfaces are as follows, namely the first interface 5a of the intercooler, the second interface 5b of the intercooler, the third interface 5c of the intercooler, and the fourth interface 5d of the intercooler.

[0058] AsFigure 9 As shown: The specific positions of the first four-way reversing valve interfaces are as follows: namely, the first interface 8a of the first four-way reversing valve, the second interface 8b of the first four-way reversing valve, the third interface 8c of the first four-way reversing valve, and the fourth interface 8d of the first four-way reversing valve.

[0059] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for outdoor heat source defrosting, characterized in that, The dual-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for defrosting of outdoor heat sources includes a low-pressure compressor (1-1), a high-pressure compressor (1-2), an outdoor finned heat exchanger (2), a PVT module (3), a throttle valve, an intercooler (5), a stop valve, a check valve, a four-way reversing valve, an indoor heat exchanger (9) and an inverter (10); The PVT module (3) is connected to the inverter (10); one end of the PVT module (3) branches, one branch passes through the fifth stop valve (7-5) and is connected to the second interface of the first four-way reversing valve (8-1), and the other branch passes through the second check valve (6-2) and is connected to the first interface of the second four-way reversing valve (8-2); the first interface of the first four-way reversing valve (8-1) is connected to the suction port of the low-pressure compressor (1-1), and the discharge port of the low-pressure compressor (1-1) is connected to the third interface of a four-way reversing valve (8-1); the fourth interface of the first four-way reversing valve (8-1) is respectively connected to the third interface of the intercooler (5), the suction port of the high-pressure compressor (1-2), and the outlet of the first check valve (6-1); the discharge port of the high-pressure compressor (1-2) is connected to the second interface of the second four-way reversing valve (8-2); the third interface of the second four-way reversing valve (8-2) passes through the indoor heat exchanger (9) and the fourth throttle valve (4-4) in sequence and then divides into two branches, one branch is connected to the fourth interface of the intercooler (5), and the other branch passes through the third stop valve (7-3) and the third throttle valve (4-3) in sequence and is connected to the second interface of the intercooler (5); the fourth interface of the second four-way reversing valve (8-2) is connected to the inlet of the first check valve (6-1); the first interface of the intercooler (5) passes through the fourth stop valve (7-4) and divides into two pipelines, one pipeline passes through the second stop valve (7-2) and the second throttle valve (4-2) in sequence and is connected to the other end of the PVT module (3); the other pipeline passes through the first stop valve (7-1) and the first throttle valve (4-1) in sequence and is connected to one end of the outdoor finned heat exchanger (2), and the other end of the outdoor finned heat exchanger (2) is connected to the pipeline between the fifth stop valve (7-5) and the second interface of the first four-way reversing valve (8-1).

2. The two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for defrosting of outdoor heat sources according to claim 1, characterized in that, The dual-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for defrosting of outdoor heat sources operates in six cycles: single-stage compression PVT heating cycle, single-stage compression air source heating cycle, dual-stage compression PVT heating cycle, dual-stage compression air source heating cycle, outdoor finned heat exchanger defrosting cycle, and single-stage compression air source refrigeration cycle.

3. The two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for defrosting of outdoor heat sources according to claim 2, characterized in that, When the dual-stage compression multi-cycle PVT-air source multi-connected heat pump air-conditioning system for outdoor heat source defrosting operates in a single-stage compression PVT heating cycle, close the first shut-off valve (7-1), the third shut-off valve (7-3), and the fifth shut-off valve (7-5), open the second shut-off valve (7-2) and the fourth shut-off valve (7-4). The first port of the second four-way reversing valve (8-2) is connected to the fourth port of the second four-way reversing valve (8-2), and the second port of the second four-way reversing valve (8-2) is connected to the third port of the second four-way reversing valve (8-2). The low-pressure compressor (1-1) shuts down, and the high-pressure compressor (1-2) starts up. The photovoltaic cells in the PVT module (3) generate electricity under sunlight irradiation, and after being adjusted by the inverter (10), it becomes electricity for user use.

4. The two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for outdoor heat source defrosting according to claim 2, wherein, When the dual-stage compression multi-cycle PVT-air source multi-connected heat pump air-conditioning system for outdoor heat source defrosting operates in a single-stage compression air source heating cycle, open the first shut-off valve (7-1), the fourth shut-off valve (7-4), and the fifth shut-off valve (7-5), close the second shut-off valve (7-2) and the third shut-off valve (7-3). The first port of the second four-way reversing valve (8-2) is connected to the fourth port of the second four-way reversing valve (8-2), and the second port of the second four-way reversing valve (8-2) is connected to the third port of the second four-way reversing valve (8-2). The low-pressure compressor (1-1) shuts down, and the high-pressure compressor (1-2) starts up. The photovoltaic cells in the PVT module (3) generate electricity under sunlight irradiation, and after being adjusted by the inverter (10), it becomes electricity for user use.

5. The dual-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for outdoor heat source defrosting according to claim 2, characterized in that, When the dual-stage compression multi-cycle PVT-air source multi-connected heat pump air-conditioning system for outdoor heat source defrosting operates in a dual-stage compression PVT heating cycle, close the first shut-off valve (7-1), open the second shut-off valve (7-2), the third shut-off valve (7-3), the fourth shut-off valve (7-4), and the fifth shut-off valve (7-5). The first port of the first four-way reversing valve (8-1) is connected to the second port of the first four-way reversing valve (8-1), and the third port of the first four-way reversing valve (8-1) is connected to the fourth port of the first four-way reversing valve (8-1). The first port of the second four-way reversing valve (8-2) is connected to the fourth port of the second four-way reversing valve (8-2), and the second port of the second four-way reversing valve (8-2) is connected to the third port of the second four-way reversing valve (8-2). Both the low-pressure compressor (1-1) and the high-pressure compressor (1-2) start up. The photovoltaic cells in the PVT module (3) generate electricity under sunlight irradiation, and after being adjusted by the inverter (10), it becomes electricity for user use.

6. The dual-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for outdoor heat source defrosting according to claim 2, characterized in that, When the dual-stage compression multi-cycle PVT-air source multi-connected heat pump air-conditioning system for outdoor heat source defrosting operates in the dual-stage compression air source heating cycle, open the first shut-off valve (7-1), the third shut-off valve (7-3), and the fourth shut-off valve (7-4), close the second shut-off valve (7-2) and the fifth shut-off valve (7-5). The first interface of the first four-way reversing valve (8-1) is communicated with the second interface of the first four-way reversing valve (8-1), the third interface of the first four-way reversing valve (8-1) is communicated with the fourth interface of the first four-way reversing valve (8-1), the second interface of the second four-way reversing valve (8-2) is communicated with the third interface of the second four-way reversing valve (8-2), and the first interface of the second four-way reversing valve (8-2) is communicated with the fourth interface of the second four-way reversing valve (8-2). The low-pressure compressor (1-1) and the high-pressure compressor (1-2) are both started. The photovoltaic cells in the PVT module (3) generate electricity under sunlight irradiation and are adjusted by the inverter (10) into electricity for user use.

7. The dual-stage compression multi-cycle PVT-air source multi-connected heat pump air-conditioning system for outdoor heat source defrosting according to claim 2, characterized in that, When the dual-stage compression multi-cycle PVT-air source multi-connected heat pump air-conditioning system for outdoor heat source defrosting operates in the outdoor finned heat exchanger defrosting cycle, open the first shut-off valve (7-1) and the second shut-off valve (7-2), close the third shut-off valve (7-3), the fourth shut-off valve (7-4), and the fifth shut-off valve (7-5). The first interface of the first four-way reversing valve (8-1) is communicated with the fourth interface of the first four-way reversing valve (8-1), the second interface of the first four-way reversing valve (8-1) is communicated with the third interface of the first four-way reversing valve (8-1), the first interface of the second four-way reversing valve (8-2) is communicated with the fourth interface of the second four-way reversing valve (8-2), and the second interface of the second four-way reversing valve (8-2) is communicated with the third interface of the second four-way reversing valve (8-2). The low-pressure compressor (1-1) is started, and the high-pressure compressor (1-2) is stopped. The opening of the first throttle valve (4-1) is adjusted to the maximum. The photovoltaic cells in the PVT module (3) generate electricity under sunlight irradiation and are adjusted by the inverter (10) into electricity for user use.

8. The two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for defrosting of outdoor heat sources according to claim 2, characterized in that, When the dual-stage compression multi-cycle PVT-air source multi-connected heat pump air-conditioning system for outdoor heat source defrosting operates in the single-stage compression air source refrigeration cycle, open the first shut-off valve (7-1) and the fourth shut-off valve (7-4), close the second shut-off valve (7-2), the third shut-off valve (7-3), and the fifth shut-off valve (7-5). The first interface of the first four-way reversing valve (8-1) is communicated with the fourth interface of the first four-way reversing valve (8-1), the second interface of the first four-way reversing valve (8-1) is communicated with the third interface of the first four-way reversing valve (8-1), the first interface of the second four-way reversing valve (8-2) is communicated with the second interface of the second four-way reversing valve (8-2), and the third interface of the second four-way reversing valve (8-2) is communicated with the fourth interface of the second four-way reversing valve (8-2). The low-pressure compressor (1-1) is started, and the high-pressure compressor (1-2) is stopped. The opening of the first throttle valve (4-1) is adjusted to the maximum.

9. The two-stage compression multi-cycle PVT-air source multi-connected heat pump air conditioning system for outdoor heat source defrosting according to any one of claims 1-8, characterized in that, The low-pressure compressor (1-1) and the high-pressure compressor (1-2) are any one of a scroll compressor, a rotary compressor, a screw compressor, and a piston compressor; the throttle valve is an electronic expansion valve, a thermostatic expansion valve, a capillary tube, or an orifice throttling device; the stop valve is a solenoid valve, a manual valve, or a ball valve.

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