Carbon dioxide cold and heat combined supply heat pump system and control method thereof

Abstract

The invention discloses a carbon dioxide cold and heat combined supply heat pump system and a control method thereof, and belongs to the technical field of carbon dioxide heat pumps. According to the carbon dioxide cold and heat combined supply heat pump system, the indoor temperature adjusting device is arranged and connected to the water tank heat supply loop to form the water tank heat supply indoor refrigeration loop, that is, the outdoor evaporator is connected with the indoor temperature adjusting device, and the cold energy originally released from the outdoor evaporator is converted into the cold energy for indoor refrigeration; the combined cooling and heating system is novel and reasonable in structural design, combined cooling and heating can be achieved, and the energy utilization efficiency of the system is improved. By effectively utilizing the cooling capacity generated in the heating process, the comprehensive utilization rate of energy is greatly increased. The problem that an existing heat pump water heater system is low in resource utilization rate is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon dioxide heat pumps, and in particular relates to a carbon dioxide combined cooling and heating heat pump system and a control method thereof. Background Art

[0002] In traditional heat pump systems, there are some technical limitations, which affect the performance and application scope of the system to a certain extent. First of all, most traditional heat pump systems can only operate in cooling mode or heating mode, and cannot achieve combined cooling and heating, which limits their application in situations where both cold air and hot water are required; for example, in the process of heating the water tank using a carbon dioxide heat pump system, the cold in the water tank is discharged into the external environment by the outdoor evaporator, resulting in a waste of cold energy. In fact, when the heat pump system performs large-scale heating operations, a large amount of cold energy will be generated. If this cold energy can be effectively collected and utilized, the comprehensive utilization rate of energy will be greatly improved. In addition, traditional heat pump systems are prone to frost in low temperature environments, affecting the normal operation of the system.

[0003] In summary, the existing heat pump system has the problem of low resource utilization. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a carbon dioxide combined cooling and heating heat pump system and a control method thereof in view of the deficiencies in the above-mentioned prior art, which has a simple design structure, high resource utilization efficiency, and low heating and cooling costs.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A carbon dioxide combined cooling and heating heat pump system comprises an exhaust port of a compressor, a first valve port and a fourth valve port of a four-way reversing valve, a water tank heat exchanger arranged on a water tank, a throttling device, an outdoor evaporator, an indoor temperature adjustment device, a second valve port and a third valve port of the four-way reversing valve, and an air intake port of the compressor, which are connected in sequence to form a system circulation loop;

[0007] When the water tank needs to be heated and the room needs to be cooled, the system circulation loop is started; when the water tank needs to be heated and the room does not need to be cooled, the system circulation loop is started, wherein the fan of the indoor temperature regulating device is turned off.

[0008] Furthermore, the indoor temperature regulating device adopts a wind tunnel system; the wind tunnel system includes a wind tunnel and an air outlet baffle;

[0009] The air inlet of the wind tunnel is connected to the air outlet of the outdoor evaporator, the air outlet of the wind tunnel is connected to the wind tunnel through a wind tunnel baffle, and the wind tunnel is connected to the indoor air through the wind outlet baffle;

[0010] When the water tank needs to be heated and the room needs to be cooled, the system circulation loop is started, wherein the air vent baffle and the wind tunnel baffle are opened;

[0011] When the water tank needs to be heated and the room does not need to be cooled, the system circulation loop is started, wherein the wind tunnel system fan, air outlet baffle and wind tunnel baffle are closed; flexible components are arranged around the wind tunnel baffle to achieve a sealed wind tunnel.

[0012] Furthermore, the indoor temperature regulating device adopts an indoor evaporator;

[0013] When the indoor evaporator is higher than the set height of the outdoor evaporator, the refrigerant outlet of the outdoor evaporator at the top is connected to the second valve port of the four-way reversing valve, the coal inlet of the outdoor evaporator at the bottom is connected to the refrigerant outlet of the indoor evaporator at the top, and the refrigerant inlet of the indoor evaporator at the bottom is connected to the outlet of the throttling device;

[0014] When the outdoor evaporator is higher than the set height of the indoor evaporator, the refrigerant outlet of the indoor evaporator at the top is connected to the second valve port of the four-way reversing valve, the coal inlet of the indoor evaporator at the bottom is connected to the refrigerant outlet of the outdoor evaporator at the top, and the refrigerant inlet of the outdoor evaporator at the bottom is connected to the outlet of the throttling device; the range of the set height is 1 meter to 1.2 meters;

[0015] When the water tank needs to be heated and the indoor room needs to be cooled, the system circulation loop is started, wherein the outdoor evaporator fan is turned off; when the water tank needs to be heated and the indoor room does not need to be cooled, the system circulation loop is started, wherein the indoor evaporator fan is turned off.

[0016] Furthermore, the diameter of the connecting pipe connected to the second valve port of the four-way reversing valve is larger than the diameter of the connecting pipe connected to the outlet of the throttling device.

[0017] Furthermore, the exhaust port of the compressor, the first valve port and the second valve port of the four-way reversing valve, the outdoor evaporator, the water tank heat exchanger, the fourth valve port and the third valve port of the four-way reversing valve, and the air intake port of the compressor are connected in sequence to form a defrost circuit; when the outdoor evaporator is frosted, the defrost circuit is started; temperature sensing bags are provided at the bottom of the water tank heat exchanger and the outdoor evaporator, and whether the outdoor evaporator is frosted is judged based on the data obtained by the temperature sensing bag, and the defrost circuit is started accordingly.

[0018] Furthermore, the throttling device adopts an electronic expansion valve, a thermal expansion valve or a capillary throttle to control the flow rate of the refrigerant.

[0019] The present invention also discloses a method for controlling a carbon dioxide combined cooling and heating heat pump system, which is used to control the above-mentioned carbon dioxide combined cooling and heating heat pump system. The method comprises the following steps:

[0020] Receive users' water tank heating and indoor cooling needs, and start the system circulation loop accordingly;

[0021] When the water tank needs to be heated and the room needs to be cooled, the system circulation loop is started, wherein the fan of the indoor temperature regulating device is turned off;

[0022] When the water needs to be heated and the room does not need to be cooled, the system circulation loop is started, wherein the fan of the indoor temperature adjustment device is turned on.

[0023] Furthermore, the method also includes the following steps: when the indoor temperature adjustment device adopts a wind tunnel system, if the water tank needs to be heated and the indoor room needs to be cooled, the system circulation loop is started, wherein the air outlet baffle of the outdoor evaporator outlet is closed and the wind tunnel baffle is opened; if the water tank needs to be heated and the indoor room does not need to be cooled, the system circulation loop is started, wherein the air outlet baffle is opened and the wind tunnel baffle is closed.

[0024] Furthermore, the method also includes the following steps: when the indoor temperature adjustment device adopts an indoor evaporator, if the water tank needs to be heated and the indoor room needs to be cooled, start the system circulation loop, wherein the outdoor evaporator fan is turned off; if the water tank needs to be heated and the indoor room does not need to be cooled, start the system circulation loop, wherein the indoor evaporator fan is turned off.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] The carbon dioxide combined heat pump system of the present invention forms a water tank heating indoor refrigeration loop by setting an indoor temperature adjustment device and connecting it to the water tank heating loop, that is, the outdoor evaporator is connected to the indoor temperature adjustment device to convert the cold originally released from the outdoor evaporator into cold for indoor refrigeration; the present invention improves the recycling rate of energy by effectively collecting and utilizing this cold, and solves the problem of low resource utilization in the existing heat pump system.

[0027] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of the embodiment 1 of the carbon dioxide combined cooling and heating heat pump system of the present invention;

[0029] Figure 2 It is a schematic diagram of the overall structure of a carbon dioxide combined cooling and heating heat pump system embodiment 2 of the present invention;

[0030] Figure 3 It is a schematic diagram of the wind tunnel system structure of Example 2 of the carbon dioxide combined cooling and heating heat pump system of the present invention;

[0031] Figure 4It is a flow chart of an embodiment of a method for controlling a carbon dioxide combined cooling and heating heat pump system of the present invention;

[0032] Description of reference numerals:

[0033] 1. Compressor; 2. Four-way reversing valve; 3. Water tank; 4. Throttling device;

[0034] 5. Outdoor evaporator; 6. Indoor evaporator; 7. Wind tunnel system; 8. Baffle;

[0035] 9. Air inlet of wind tunnel; 10. Air outlet of wind tunnel; 11. Air outlet baffle; 12. First valve port; 13. Second valve port; 14. Third valve port; 15. Fourth valve port. DETAILED DESCRIPTION

[0036] Example 1 of CO2 combined cooling and heating heat pump system:

[0037] like Figure 1 As shown, the carbon dioxide combined cooling and heating heat pump system includes the exhaust port of the compressor 1, the first valve port 12 and the fourth valve port 15 of the four-way reversing valve 2, the water tank heat exchanger arranged on the water tank 3, the throttling device 4, the outdoor evaporator 5, the indoor temperature adjustment device, the second valve port 13 and the third valve port 14 of the four-way reversing valve 2, and the air intake port of the compressor 1, which constitute the system circulation loop. The throttling device 4 adopts an electronic expansion valve, a thermal expansion valve or a capillary throttle to control the flow rate of the refrigerant. The outdoor evaporator 5 adopts an air-cooled water tank heat exchanger, and the inlet wind comes from the surrounding environment. The water tank heat exchanger can adopt a plate exchanger, a shell and tube heat exchanger or a water storage tank heat exchanger.

[0038] When the water tank 3 needs to be heated and the room needs to be cooled, the system circulation loop is started; when the water tank 3 needs to be heated and the room does not need to be cooled, the system circulation loop is started, wherein the fan of the indoor temperature regulating device is turned off.

[0039] In order to better realize the recovery of the cooling capacity of the heat pump system, the indoor temperature adjustment device adopts an indoor evaporator 6. The refrigerant inlet of the indoor evaporator 6 is connected to the refrigerant outlet of the outdoor evaporator 5.

[0040] That is to say, when the water tank 3 needs to be heated and the indoor room needs to be cooled, the system circulation loop is started, wherein the outdoor evaporator 5 fan is turned off; when the water tank 3 needs to be heated and the indoor room does not need to be cooled, the system circulation loop is started, wherein the indoor evaporator 6 fan is turned off. That is, the high-temperature and high-pressure carbon dioxide flows from the exhaust port of the compressor 1 through the first valve port 12 and the fourth valve port 15 of the four-way reversing valve 2, and then flows into the water tank heat exchanger for heat exchange, heating the water in the water tank 3. After the heat exchange, the high-pressure and low-temperature carbon dioxide flows through the throttling device 4 and is converted into low-pressure and low-temperature carbon dioxide, flows through the outdoor evaporator 5 to dissipate the cold energy into the outdoor air, and then passes through the cold coal pipeline of the indoor evaporator 6, flows through the second valve port 13 and the third valve port 14 of the four-way reversing valve 2 and returns to the compressor 1 to complete the heating of the water tank 3. Since the indoor evaporator 6 is not turned on when the indoor room is not cooled, the outdoor evaporator 5 at this time is only equivalent to a pipeline and has no other functions.

[0041] In addition, when the water tank 3 does not need to be heated and the room needs to be cooled, there is no waste cooling generated by heating the water tank 3. If the room does need to be cooled, this system can also be implemented, but there is a problem of energy waste. That is, when the water tank 3 does not need to be heated and the room needs to be cooled, the control system circulation loop is turned on, wherein the outdoor evaporator 5 fan is turned off, and in order to avoid damaging the water tank 3, the hot water in the water tank 3 needs to be discharged at a set time interval.

[0042] That is, after the low-pressure and low-temperature carbon dioxide flows out of the throttling device 4, it flows through the refrigerant pipeline of the outdoor evaporator 5 and then flows into the indoor evaporator 6 for indoor cooling. At this time, the outdoor evaporator 5 is also only used as a pipeline. When recovering cold energy, the present invention does not store the cold energy, but directly uses it where it is needed, which reduces the cost of energy storage, and also realizes the recovery and utilization of the discarded cold energy, thereby improving the energy utilization rate of the heat pump system.

[0043] In order to improve the heat exchange efficiency, in actual use, the indoor heat exchanger 6 is generally required to be installed at a height of not less than 2.2 meters. The reason is that cold air will sink, and installing it higher is conducive to indoor cold convection circulation; the room temperature reaches the standard faster. The installation position of the outdoor evaporator 5 is set according to the installation environment; that is, the outdoor evaporator 5 and the indoor evaporator 6 may have inconsistent installation heights during installation. Since the inlet of the evaporator is a gas-liquid two-phase flow with a majority of liquid, placing the inlet on the lower side of the heat exchanger is conducive to improving the heat exchange efficiency.

[0044] Specifically, when the indoor evaporator 6 is higher than the set height of the outdoor evaporator 5, the refrigerant outlet of the outdoor evaporator 5 located at the top is connected to the second valve port 13 of the four-way reversing valve 2, the coal inlet of the outdoor evaporator 5 located at the bottom is connected to the refrigerant outlet of the indoor evaporator 6 located at the top, and the refrigerant inlet of the indoor evaporator 6 located at the bottom is connected to the outlet of the throttling device 4. When the outdoor evaporator 5 is higher than the set height of the indoor evaporator 6, the refrigerant outlet of the indoor evaporator 6 located at the top is connected to the second valve port 13 of the four-way reversing valve 2, the coal inlet of the indoor evaporator 6 located at the bottom is connected to the refrigerant outlet of the outdoor evaporator 5 located at the top, and the refrigerant inlet of the outdoor evaporator 5 located at the bottom is connected to the outlet of the throttling device 4; the range of the above set height is 1 meter to 1.2 meters. That is, the evaporator with a relatively high installation position is set on the refrigerant outflow side, and the evaporator with a relatively low installation position is set on the refrigerant inflow side, so as to improve the heat exchange efficiency of the refrigerant.

[0045] In order to reduce the flow fluctuation of the refrigerant, the diameter of the connecting pipe connected to the second valve port 13 of the four-way reversing valve 2 is larger than the diameter of the connecting pipe connected to the outlet of the throttling device 4. Flow fluctuation may lead to reduced system efficiency and equipment damage; by optimizing the pipe diameter, the fluctuation of the refrigerant flow can be reduced, thereby increasing the service life of the system.

[0046] In order to ensure the normal operation of the system circulation loop, the exhaust port of the compressor 1, the first valve port 12, the second valve port 13, the outdoor evaporator 5, the water tank heat exchanger, the fourth valve port 15, the third valve port 14, and the air intake port of the compressor 1 are connected in sequence to form a defrosting loop; when the outdoor evaporator 5 is frosted, the defrosting loop is started. The bottom of the water tank heat exchanger and the outdoor evaporator 5 are both provided with a temperature sensing package, and the data obtained by the temperature sensing package is used to determine whether the outdoor evaporator 5 is frosted, and the defrosting loop is started accordingly. The traditional heat pump system is prone to frost in a low temperature environment, which affects the normal operation of the system. The present invention solves the frosting problem by setting up technical means such as a defrosting loop and a temperature sensing package, and improves the stability and reliability of the system in a low temperature environment. At the same time, the defrosting pipeline of the present application utilizes the refrigeration circuit of the water tank 3 of the heat pump system, and defrosting is achieved by the reasonable reversing of the four-way reversing valve 2. Since the defrosting generally lasts for a short time, it will not affect the heating water tank 3. Compared with re-establishing a set of heated defrosting pipelines, the solution of the present application has lower costs and more convenient operation.

[0047] Example 2 of CO2 combined cooling and heating heat pump system:

[0048] like Figure 2 , 3As shown, the difference between this embodiment and the embodiment 1 of the carbon dioxide combined cooling and heating heat pump system is that: the indoor temperature adjustment device in this embodiment adopts a wind tunnel system 7, and the wind tunnel system 7 includes a wind tunnel and an air outlet baffle 11; the air inlet 9 of the above-mentioned wind tunnel is connected with the air outlet of the outdoor evaporator 5, and the air outlet 10 of the above-mentioned wind tunnel is connected with the wind tunnel through the wind tunnel baffle 8, and the above-mentioned wind tunnel is connected with the indoor air through the air outlet baffle 11.

[0049] During use, when the water tank 3 needs to be heated and the room needs to be cooled, the system circulation loop is started, wherein the air outlet baffle 11 and the wind tunnel baffle 8 are opened; when the water tank 3 needs to be heated and the room does not need to be cooled, the system circulation loop is started, wherein the wind tunnel system fan, the air outlet baffle 11 and the wind tunnel baffle 8 are closed.

[0050] In order to ensure that the cold air can be transported indoors as intact as possible, flexible components are arranged around the wind tunnel baffle 8 to seal the wind tunnel, and preferably the flexible components are sealing strips. That is, if the indoor needs to be cooled, the wind tunnel baffle 8 and the air outlet baffle 11 are opened to send cold air to the indoor; when the indoor does not need to be cooled, but the water tank 3 needs to be heated, the wind tunnel baffle 8 and the air outlet baffle 11 are closed; the cold air from the outdoor evaporator 5 is discharged to the outdoors through the air outlet. The wind tunnel baffle 8 and the air outlet baffle 11 are opened and closed relative to the air duct, and the opening and closing movement is a translation or rotation movement.

[0051] In addition, when the water tank 3 does not need to be heated and the indoor temperature needs to be cooled, the system circulation loop is started, wherein the air outlet baffle and the wind tunnel baffle 8 of the air outlet of the outdoor evaporator 5 are opened.

[0052] The structural design of the present invention is novel and reasonable, and can realize the combined supply of cooling and heating, thereby improving the energy utilization efficiency of the system. By effectively utilizing the cooling energy generated during the heating process, the present invention greatly improves the recycling rate of energy.

[0053] The other parts of this embodiment are implemented with reference to the first embodiment of the carbon dioxide combined cooling and heating heat pump system, and will not be described in detail here.

[0054] Carbon dioxide combined cooling and heating heat pump system control method embodiment:

[0055] like Figure 4 The carbon dioxide combined heat supply and cooling heat pump system control method shown is used to control the above-mentioned carbon dioxide combined heat supply and cooling heat pump system. The carbon dioxide combined heat supply and cooling heat pump system is implemented with reference to the above-mentioned carbon dioxide combined heat supply and cooling heat pump system embodiments 1 and 2, which will not be repeated here. The method includes the following steps:

[0056] First, the user's water tank heating and indoor cooling requirements are received, and the system circulation loop is started accordingly; specifically, when the water tank 3 needs to be heated and the indoor needs to be cooled, the system circulation loop is started, wherein the fan of the indoor temperature adjustment device is turned off; when the water tank 3 needs to be heated and the indoor does not need to be cooled, the system circulation loop is started, wherein the fan of the indoor temperature adjustment device is turned on. That is, when the indoor needs to be cooled, the cold energy exchanged by the heat pump system for heating the water tank 3 is used for indoor cooling. Since the cost of storing this kind of cold energy is relatively high, the cost of storing cold energy can be reduced by using it on-site, while also achieving efficient use of energy.

[0057] Specifically, the indoor temperature adjustment device can be a wind tunnel system or an evaporator. The wind tunnel system has an advantage in terms of precise temperature control, while the evaporator has better heat transfer efficiency. You can choose according to actual needs.

[0058] The method also includes the following steps: when the indoor temperature adjustment device adopts a wind tunnel system, if the water tank 3 needs to be heated and the indoor needs to be cooled, the system circulation loop is started, wherein the air outlet baffle 11 and the wind tunnel baffle 8 are opened; if the water tank 3 needs to be heated and the indoor does not need to be cooled, the system circulation loop is started, wherein the wind tunnel system fan, the air outlet baffle 11 and the wind tunnel baffle 8 are closed. That is, the cold air is output by the outdoor evaporator 5; when the indoor needs to be cooled, the cold air first enters the wind tunnel, and then is sent into the indoor by the fan of the wind tunnel system to meet the indoor cooling demand; when the indoor does not need to be cooled, the cold air flows into the outdoor air from the air outlet of the outdoor evaporator 5.

[0059] The method also includes the following steps: when the indoor temperature adjustment device uses the indoor evaporator 6, if the water tank 3 needs to be heated and the indoor needs to be cooled, the system circulation loop is started, wherein the fan of the outdoor evaporator 5 is turned off; if the water tank 3 needs to be heated and the indoor does not need to be cooled, the system circulation loop is started, wherein the fan of the indoor evaporator 6 is turned off. That is, the required cooling capacity indoors is obtained by relying on the indoor evaporator 6, and at this time the fan of the outdoor evaporator 5 is turned off, and the outdoor evaporator 5 is equivalent to a refrigerant pipeline.

[0060] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A carbon dioxide combined cooling and heating heat pump system, characterized in that: The system comprises an exhaust port of a compressor (1), a first valve port (12) and a fourth valve port (15) of a four-way reversing valve (2), a water tank heat exchanger arranged on a water tank (3), a throttling device (4), an outdoor evaporator (5), an indoor temperature regulating device, a second valve port (13) and a third valve port (14) of the four-way reversing valve (2), and an air intake port of the compressor (1), which are connected in sequence to form a system circulation loop; When the water tank (3) needs to be heated and the room needs to be cooled, the system circulation loop is started; when the water tank (3) needs to be heated and the room does not need to be cooled, the system circulation loop is started, wherein the fan of the indoor temperature adjustment device is turned off.

2. A carbon dioxide combined cooling and heating heat pump system according to claim 1, characterized in that: The indoor temperature regulating device adopts a wind tunnel system (7); the wind tunnel system (7) includes a wind tunnel and an air outlet baffle (11); The air inlet (9) of the wind tunnel is connected to the air outlet of the outdoor evaporator (5), the air outlet (10) of the wind tunnel is connected to the wind tunnel through a wind tunnel baffle (8), and the wind tunnel is connected to the indoor air through a wind outlet baffle (11); When the water tank (3) needs to be heated and the room needs to be cooled, the system circulation loop is started, wherein the air outlet baffle (11) and the wind tunnel baffle (8) are opened; when the water tank (3) needs to be heated and the room does not need to be cooled, the system circulation loop is started, wherein the wind tunnel system fan, the air outlet baffle (11) and the wind tunnel baffle (8) are closed; The wind tunnel baffle (8) is provided with flexible components around it to achieve sealing of the wind tunnel.

3. A carbon dioxide combined cooling and heating heat pump system according to claim 1, characterized in that: The indoor temperature regulating device adopts an indoor evaporator (6); When the indoor evaporator (6) is higher than the set height of the outdoor evaporator (5), the refrigerant outlet located at the top of the outdoor evaporator (5) is connected to the second valve port (13) of the four-way reversing valve (2), the coal inlet located at the bottom of the outdoor evaporator (5) is connected to the refrigerant outlet located at the top of the indoor evaporator (6), and the refrigerant inlet located at the bottom of the indoor evaporator (6) is connected to the outlet of the throttling device (4); When the outdoor evaporator (5) is higher than the set height of the indoor evaporator (6), the refrigerant outlet located at the top of the indoor evaporator (6) is connected to the second valve port (13) of the four-way reversing valve (2), the coal inlet located at the bottom of the indoor evaporator (6) is connected to the refrigerant outlet located at the top of the outdoor evaporator (5), and the refrigerant inlet located at the bottom of the outdoor evaporator (5) is connected to the outlet of the throttling device (4); the range of the set height is 1 meter to 1.2 meters; When the water tank (3) needs to be heated and the indoor room needs to be cooled, the system circulation loop is started, wherein the outdoor evaporator (5) fan is turned off; when the water tank (3) needs to be heated and the indoor room does not need to be cooled, the system circulation loop is started, wherein the indoor evaporator (6) fan is turned off.

4. A carbon dioxide combined cooling and heating heat pump system according to claim 4, characterized in that: The diameter of the connecting pipe connected to the second valve port (13) of the four-way reversing valve (2) is larger than the diameter of the connecting pipe connected to the outlet of the throttling device (4).

5. A carbon dioxide combined cooling and heating heat pump system according to any one of claims 1 to 4, characterized in that: The exhaust port of the compressor (1), the first valve port (12) and the second valve port (13) of the four-way reversing valve (2), the outdoor evaporator (5), the water tank heat exchanger, the fourth valve port (15) and the third valve port (14) of the four-way reversing valve (2), and the air intake port of the compressor (1) are connected in sequence to form a defrosting circuit; when the outdoor evaporator (5) is frosted, the defrosting circuit is started; The bottom of the water tank heat exchanger and the outdoor evaporator (5) are both provided with temperature sensing packages, and whether the outdoor evaporator (5) is frosted is determined based on data obtained by the temperature sensing packages, and the defrosting circuit is started accordingly.

6. A carbon dioxide combined cooling and heating heat pump system according to claim 1, characterized in that: The throttling device (4) adopts an electronic expansion valve, a thermal expansion valve or a capillary throttle to control the flow rate of the refrigerant.

7. A method for controlling a carbon dioxide combined cooling and heating heat pump system, characterized in that: The method is used to control the carbon dioxide combined cooling and heating heat pump system according to any one of claims 1 to 6, and the method comprises the following steps: Receive users' water tank heating and indoor cooling needs, and start the system circulation loop accordingly; When the water tank (3) needs to be heated and the room needs to be cooled, the system circulation loop is started, wherein the fan of the indoor temperature adjustment device is turned off; When the water tank (3) needs to be heated and the room does not need to be cooled, the system circulation loop is started, wherein the fan of the indoor temperature adjustment device is turned on.

8. A method for controlling a carbon dioxide combined cooling and heating heat pump system according to claim 7, characterized in that: The method further comprises the following steps: when the indoor temperature adjustment device adopts a wind tunnel system, if the water tank (3) needs to be heated and the indoor temperature needs to be cooled, the system circulation loop is started, wherein the air outlet baffle (11) and the wind tunnel baffle (8) are opened; if the water tank (3) needs to be heated and the indoor temperature does not need to be cooled, the system circulation loop is started, wherein the wind tunnel system fan, the air outlet baffle (11) and the wind tunnel baffle (8) are closed.

9. A method for controlling a carbon dioxide combined cooling and heating heat pump system according to claim 7, characterized in that: The method further comprises the following steps: when the indoor temperature regulating device adopts an indoor evaporator (6), if the water tank (3) needs to be heated and the indoor temperature needs to be cooled, the system circulation loop is started, wherein the fan of the outdoor evaporator (5) is turned off; if the water tank (3) needs to be heated and the indoor temperature does not need to be cooled, the system circulation loop is started, wherein the fan of the indoor evaporator (6) is turned off.

Images