A heat pump water heater and its control method

Abstract

The present invention relates to a heat pump water heater and a control method thereof. The heat pump water heater includes a housing, a CO2 heat pump system, a phase change heat exchanger, and a water tank disposed within the housing; the CO2 heat pump system includes a compressor, a plate heat exchanger, a throttling element, and an evaporator. A first refrigerant flow path and a first heat exchange flow path are provided within the plate heat exchanger. The compressor, the first refrigerant flow path, the throttling element, and the evaporator are sequentially connected by pipelines to form a refrigerant circuit; a first water inlet and a first water outlet are provided on the housing, a second water inlet communicating with the first water inlet and a second water outlet communicating with the first water outlet are provided on the water tank, and the water tank is connected to the first heat exchange flow path through a pipeline; a second refrigerant flow path, a second heat exchange flow path, and a phase change component in contact with both the second refrigerant flow path and the second heat exchange flow path are provided in the phase change heat exchanger. The second refrigerant flow path is connected in parallel with the first refrigerant flow path in the refrigerant circuit, and it has multiple hot water heating modes and high energy efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump water heaters, and particularly to a heat pump water heater and a control method thereof. Background Art

[0002] With the improvement of people's living standards, water heaters have gradually become essential household appliances. Currently, the main types of water heaters include gas water heaters, electric water heaters, and solar water heaters, etc. Among them: Gas water heaters will produce waste gas, which is likely to cause carbon monoxide poisoning; Electric water heaters consume a large amount of energy and are extremely prone to electric shock accidents; Solar water heaters are greatly affected by the weather and are inconvenient to use. Therefore, heat pump water heaters have gradually been applied to people's lives. However, the refrigerants of current heat pump water heaters are mainly traditional refrigerants such as R22 and R410A, which will damage the ozone layer and cause greenhouse effects. Moreover, the hot water heating modes of most existing heat pump water heaters are single and cannot meet the diverse hot water usage requirements. Summary of the Invention

[0003] Based on this, the purpose of the present invention is to provide a heat pump water heater and a control method thereof, which have multiple hot water heating modes and can meet different hot water usage requirements.

[0004] A heat pump water heater, comprising:

[0005] A housing, on which a first water inlet and a first water outlet are provided;

[0006] A CO2 heat pump system, arranged inside the housing, including a compressor, a plate heat exchanger, a throttling element, and an evaporator. A first refrigerant flow channel and a first heat exchange flow channel are thermally conducted inside the plate heat exchanger. The compressor, the first refrigerant flow channel, the throttling element, and the evaporator are sequentially connected by pipelines to form a refrigerant circuit;

[0007] A water tank, arranged inside the housing, on which a second water inlet communicating with the first water inlet and a second water outlet communicating with the first water outlet are provided. The water tank is connected to the first heat exchange flow channel through a pipeline;

[0008] A phase change heat exchanger, arranged inside the housing. A second refrigerant flow channel, a second heat exchange flow channel, and a phase change component are provided in the phase change heat exchanger. Both the second refrigerant flow channel and the second heat exchange flow channel are in contact with the phase change component. The second refrigerant flow channel is connected in series or in parallel with the first refrigerant flow channel in the refrigerant circuit. The water inlet end of the second heat exchange flow channel is communicated with the first water inlet, and the water outlet end of the second heat exchange flow channel is communicated with the first water outlet.

[0009] For the heat pump water heater of the present invention, the water tank is communicated with the first heat exchange flow channel through a pipeline. The second refrigerant flow channel of the phase change heat exchanger is connected in parallel with the first refrigerant flow channel in the refrigerant circuit, and the water inlet end of the second heat exchange flow channel of the phase change heat exchanger is communicated with the first water inlet, and the water outlet end of the second heat exchange flow channel is communicated with the first water outlet. It can heat the water entering the heat pump water heater through the first water inlet by using different heating circuits through the plate heat exchanger and the phase change heat exchanger, meeting different hot water usage requirements; moreover, through the refrigerant circuit, the second refrigerant flow channel and the phase change component, the heat can be stored in the phase change component by making full use of the electricity consumption during the low grid valley period, and the water can be heated by using the second heat exchange flow channel, improving the electric energy utilization efficiency.

[0010] Further, a third water outlet is provided on the water tank, and the third water outlet is communicated with the water inlet end of the second heat exchange flow channel through a pipeline; a third solenoid valve is provided on the pipeline between the third water outlet and the water inlet end of the second heat exchange flow channel, and a fourth solenoid valve is provided on the pipeline between the first water outlet and the second water outlet.

[0011] Further, the refrigerant circuit further includes a first solenoid valve and a second solenoid valve. The two ends of the first solenoid valve are respectively communicated with the compressor and the inlet end of the first refrigerant flow channel, and the two ends of the second solenoid valve are respectively communicated with the compressor and the inlet end of the second refrigerant flow channel.

[0012] Further, a flow meter is provided at the first water outlet.

[0013] Further, an air inlet and an air outlet are provided on the housing. The CO2 heat pump system further includes a centrifugal fan provided inside the housing. The centrifugal fan is used to drive the air located outside the housing to enter the housing through the air inlet, and drive the air located inside the housing to flow out of the housing through the air outlet. The indoor air enters the housing through the air inlet under the action of the centrifugal fan. The air entering the housing exchanges heat with the evaporator and becomes dry cold air, and then the dry cold air flows out of the housing through the air outlet under the action of the centrifugal fan and enters the room. It can cool and dehumidify the indoor air, realizing multiple functions in one machine.

[0014] Further, the heat pump water heater further includes a temperature detection component, and the temperature detection component includes a first temperature detector provided in the water tank, a second temperature detector provided in the phase change heat exchanger, and a third temperature detector provided at the air inlet.

[0015] Further, a partition is provided inside the housing. The partition divides the cavity inside the housing into a first cavity and a second cavity. The CO2 heat pump system is disposed in the first cavity, and the phase change heat exchanger and the water tank are disposed in the second cavity. Moreover, a heat insulation layer is provided between the phase change heat exchanger and the water tank and the inner wall of the second cavity. The heat insulation layer can not only insulate the phase change heat exchanger and the water tank to reduce the probability of heat loss, but also improve the mechanical strength between the housing and the phase change heat exchanger and the water tank.

[0016] Further, a chassis is provided at the bottom of the first cavity. The compressor, the plate heat exchanger, and the evaporator are all connected to the chassis, which facilitates the installation of the compressor, the plate heat exchanger, and the evaporator.

[0017] Further, the CO2 heat pump system, the phase change heat exchanger, and the water tank are arranged in the housing from top to bottom in sequence; or, the CO2 heat pump system, the phase change heat exchanger, and the water tank are arranged in the housing in sequence along the length direction of the housing.

[0018] The present invention also provides a control method for a heat pump water heater, which is used to control the heat pump water heater of the present invention, and includes the following steps:

[0019] S1: Obtain the ambient temperature, and obtain the heating capacity of the CO2 heat pump system according to the ambient temperature and the ambient temperature - heating capacity data.

[0020] S2: Obtain the heat of the hot water according to the historical hot water output volume and the historical hot water outlet temperature of the water tank.

[0021] S3: Obtain the water temperature of the water tank and the temperature of the phase change heat exchanger.

[0022] S4: When the heating capacity is greater than or equal to the heat of the hot water, determine whether the water temperature of the water tank and the phase change heat exchanger meet the conditions, and adopt the following hot water supply modes: (1) When the water temperature of the water tank is greater than or equal to the temperature threshold and the temperature of the phase change heat exchanger is less than the temperature threshold, use the water tank to supply hot water; (2) When the water temperature of the water tank is less than the temperature threshold and the temperature of the phase change heat exchanger is greater than or equal to the temperature threshold, use the refrigerant circuit and the second refrigerant flow path to heat the water entering the second heat exchange flow path to supply hot water; (3) When the water temperature of the water tank is greater than or equal to the temperature threshold and the temperature of the phase change heat exchanger is greater than or equal to the temperature threshold, use the water tank to supply hot water or use the refrigerant circuit and the second refrigerant flow path to heat the water entering the second heat exchange flow path to supply hot water; (4) When the water temperature of the water tank is less than the temperature threshold and the temperature of the phase change heat exchanger is less than the temperature threshold, determine the operation time of the power grid, and when the operation time of the power grid is in the peak period, use the refrigerant circuit and the second refrigerant flow path to heat the water entering the second heat exchange flow path to supply hot water, and when the operation time of the power grid is in the low valley period, use the refrigerant circuit to heat the water entering the first heat exchange flow path to supply hot water;

[0023] Or,

[0024] When the heating capacity is less than the heat of the hot water, determine the operation time of the power grid, and when the operation time of the power grid is in the peak period, use the refrigerant circuit and the second refrigerant flow path to heat the water entering the second heat exchange flow path to supply hot water, and when the operation time of the power grid is in the low valley period, use the refrigerant circuit to heat the water entering the first heat exchange flow path to supply hot water.

[0025] For better understanding and implementation, the present invention will be described in detail below with reference to the accompanying drawings. Description of the Drawings

[0026] Figure 1 It is a schematic structural diagram of the heat pump water heater in the present invention;

[0027] Figure 2 is Figure 1 a schematic diagram of the pipeline connection of the CO2 heat pump system with the water tank and the phase change heat exchanger in;

[0028] Figure 3 It is a schematic flow chart of the control method of the heat pump water heater in the present invention;

[0029] Among them, the reference numerals of each drawing are:

[0030] 1. Housing; 11. Air inlet; 12. Air outlet; 13. First water inlet; 14. First water outlet; 15. Partition; 16. Thermal insulation layer; 2. CO2 heat pump system; 21. Compressor; 22. First solenoid valve; 23. Plate heat exchanger; 231. First refrigerant flow channel; 232. First heat exchange flow channel; 24. Second solenoid valve; 25. Regenerator; 26. Throttling element; 27. Evaporator; 28. Centrifugal fan; 3. Phase change heat exchanger; 31. Second refrigerant flow channel; 32. Second heat exchange flow channel; 33. Phase change component; 4. Water tank; 41. Second water inlet; 42. Flowmeter; 43. Second water outlet; 44. Third water outlet; 45. Fourth water inlet; 46. Fourth water outlet; 47. Third solenoid valve; 48. Fourth solenoid valve. Detailed implementation manners

[0031] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all of them. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by the embodiments of the present application.

[0032] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. The singular forms "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term " / and / " as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0033] When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present application. On the contrary, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims. In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0034] In addition, in the description of the present application, unless otherwise specified, "a plurality of" means two or more. " / and / " describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0035] It should be understood that the embodiments of the present application are not limited to the exact structures already described and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the embodiments of the present application is only limited by the appended claims.

[0036] Embodiment 1

[0037] Referring to Figure 1 and Figure 2 , this embodiment provides a heat pump water heater, which includes a housing 1, a CO2 heat pump system 2, a phase change heat exchanger 3 and a water tank 4, and the CO2 heat pump system 2, the phase change heat exchanger 3 and the water tank 4 are all arranged in the housing 1.

[0038] A first water inlet 13 and a first water outlet 14 are arranged on the housing 1; the CO2 heat pump system 2 includes a compressor 21, a plate heat exchanger 23, a throttling element 26 and an evaporator 27. A first refrigerant flow channel 231 and a first heat exchange flow channel 232 are arranged inside the plate heat exchanger 23 in a heat conduction manner. The compressor 21, the first refrigerant flow channel 231, the throttling element 26 and the evaporator 27 are connected in sequence by pipelines to form a refrigerant circuit, and CO2 circulates in the refrigerant circuit.

[0039] Moreover, in order to improve the utilization efficiency of heat in the refrigerant circuit, the CO2 heat pump system 2 further includes a regenerator 25 connected between the outlet end of the first refrigerant flow channel 231 and the throttling element 26, and the refrigerant circuit is as follows: High-temperature and high-pressure CO2 flows out of the compressor 21 and enters the first refrigerant flow channel 231; the high-temperature and high-pressure CO2 in the first refrigerant flow channel 231 exchanges heat with the water in the first heat exchange flow channel 232 and becomes medium-temperature and high-pressure CO2; the medium-temperature and high-pressure CO2 enters the first branch of the regenerator 25, and part of the heat is recovered by the regenerator 25 and becomes low-temperature and high-pressure CO2; the low-temperature and high-pressure CO2 becomes low-temperature and low-pressure CO2 after passing through the throttling element 26; the low-temperature and low-pressure CO2 enters the evaporator 27 and becomes medium-temperature and low-pressure CO2; the medium-temperature and low-pressure CO2 enters the second branch of the regenerator 25 and absorbs the heat recovered by the regenerator 25 and becomes high-temperature and low-pressure CO2; then, the high-temperature and low-pressure CO2 enters the compressor 21 and becomes high-temperature and high-pressure CO2, and circulates in this way.

[0040] It should be noted that in the present invention, the throttling element 26 is any one of a throttle valve, a capillary tube or an expansion valve.

[0041] The water tank 4 is provided with a second water inlet 41 communicating with the first water inlet 13 and a second water outlet 43 communicating with the first water outlet 14. The water tank 4 is connected to the first heat exchange flow path 232 through a pipeline, so that the water in the water tank 4 can be heated through the first heat exchange flow path 232. Moreover, a fourth electromagnetic valve 48 is provided on the pipeline between the first water outlet 14 and the second water outlet 43. When it is necessary to supply hot water using the water tank 4, the fourth electromagnetic valve 48 can be opened.

[0042] Refer to Figure 1 and Figure 2 , the water tank 4 is further provided with a fourth water inlet 45 and a fourth water outlet 46. The fourth water inlet 45 is connected to the water inlet end of the first heat exchange flow path 232 through a pipeline, and the fourth water outlet 46 is connected to the water outlet end of the first heat exchange flow path 232 through a pipeline. During operation, the water in the water tank 4 flows through the fourth water outlet 46 and the water inlet end of the first heat exchange flow path 232 in sequence and then flows into the first heat exchange flow path 232; the water in the first heat exchange flow path 232 exchanges heat with the high-temperature and high-pressure CO2 in the first refrigerant flow path 231 and becomes hot water; then the hot water flows through the water outlet end of the first refrigerant flow path 231 and the fourth water inlet 45 in sequence and then returns to the water tank 4, thereby heating the water in the water tank 4.

[0043] The phase change heat exchanger 3 is provided with a second refrigerant flow path 31, a second heat exchange flow path 32 and a phase change component 33. Both the second refrigerant flow path 31 and the second heat exchange flow path 32 are in contact with the phase change component 33. The second refrigerant flow path 31 is connected in parallel with the first refrigerant flow path 231 in the refrigerant circuit. The water inlet end of the second heat exchange flow path 32 is communicated with the first water inlet 13, and the water outlet end of the second heat exchange flow path 32 is communicated with the first water outlet 14. Thus, the heat of the high-temperature and high-pressure CO2 in the refrigerant circuit is stored in the phase change component 33 through the second refrigerant flow path 31, and the heat stored in the phase change component 33 is used to heat the water entering the second heat exchange flow path 32. It can store heat in the phase change component 33 by using the electricity in the low valley period of the power grid, improving the utilization efficiency of electric energy.

[0044] Moreover, in this embodiment, a third water outlet 44 is provided on the water tank 4. The third water outlet 44 is communicated with the water inlet end of the second heat exchange flow channel 32, and a third electromagnetic valve 47 is provided on the pipeline between the third water outlet 44 and the water inlet end of the second heat exchange flow channel 32. During operation: High-temperature and high-pressure CO2 enters the second refrigerant flow channel 31 through the inlet end of the second refrigerant flow channel 31; The high-temperature and high-pressure CO2 entering the second refrigerant flow channel 31 is absorbed by the phase change component 33 and then becomes medium-temperature and high-pressure CO2 and flows back to the refrigerant circuit. At this time, the heat of the high-temperature and high-pressure CO2 is stored in the phase change component 33; Open the third electromagnetic valve 47, and the water in the water tank 4 sequentially flows through the third water outlet 44 and the water inlet end of the second heat exchange flow channel 32 and then enters the second heat exchange flow channel 32; The water entering the second heat exchange flow channel 32 absorbs the heat stored in the phase change component 33 and then becomes hot water, and flows to the first water outlet 14 through the water outlet end of the second heat exchange flow channel 32, so as to heat the water in the water tank 4 through the refrigerant circuit and the phase change heat exchanger 3.

[0045] In the present invention, Figure 2 The hollow closed arrow in represents the flow direction of CO2, and the solid closed arrow represents the flow direction of water.

[0046] Referring to Figure 2 , the refrigerant circuit further includes a first electromagnetic valve 22 and a second electromagnetic valve 24. The two ends of the first electromagnetic valve 22 are respectively communicated with the compressor 21 and the inlet end of the first refrigerant flow channel 231, and the outlet end of the first refrigerant flow channel 231 is communicated with the regenerator 25; The two ends of the second electromagnetic valve 24 are respectively communicated with the compressor 21 and the inlet end of the second refrigerant flow channel 31, and the outlet end of the second refrigerant flow channel 31 is communicated with the regenerator 25, so as to select different hot water heating modes by controlling the opening and closing of the first electromagnetic valve 22 and the second electromagnetic valve 24.

[0047] In order to be able to monitor the usage amount of hot water in real time, a flow meter 42 is provided on the first water outlet 14, so that the usage amount of hot water can be monitored through the flow meter 42.

[0048] Preferably, in this embodiment, an air inlet 11 and an air outlet 12 are provided on a side of the housing 1 close to the CO2 heat pump system 2. The CO2 heat pump system 2 further includes a centrifugal fan 28 disposed within the housing 1. The centrifugal fan 28 can drive the indoor air to enter the housing 1 through the air inlet 11. The air entering the housing 1 is cooled by absorbing heat from the evaporator 27, and condensed water is separated out to become dry cold air. Then, the dry cold air returns to the indoor through the air outlet 12 under the action of the centrifugal fan 28, so as to realize the cooling and dehumidification of the indoor air, achieving multiple functions with one machine.

[0049] Preferably, in this embodiment, the heat pump water heater further includes a temperature detection component. The temperature detection component includes a first temperature detector disposed in the water tank 4, a second temperature detector disposed in the phase change heat exchanger 3, and a third temperature detector disposed at the air inlet 11. Specifically, when setting: the first temperature detector can be disposed at any position within the water tank 4 as long as it can detect the water temperature within the water tank 4; the second temperature detector is disposed on the second refrigerant flow path 31, or on the second heat exchange flow path 32, or on the phase change component 33; the third temperature detector is disposed at any position where the temperature of the indoor air entering the housing 1 can be detected.

[0050] In this embodiment, a partition 15 is provided inside the housing 1. The partition 15 divides the cavity inside the housing 1 into a first cavity and a second cavity. The CO2 heat pump system 2 is disposed in the first cavity, and the phase change heat exchanger 3 and the water tank 4 are disposed in the second cavity. Moreover, a heat insulation layer 16 is filled between the phase change heat exchanger 3 and the water tank 4 and the inner wall of the second cavity. Through the heat insulation layer 16, not only can the heat storage capacity of the phase change heat exchanger 3 and the water tank 4 be improved, but also the mechanical strength between the housing 1 and the phase change heat exchanger 3 and the water tank 4 can be improved.

[0051] Moreover, to facilitate the installation of the CO2 heat pump system 2, a chassis is provided at the bottom of the first cavity. The compressor 21, the plate heat exchanger 23, the regenerator 25, the evaporator 27, and the centrifugal fan 28 are all connected to the chassis. Moreover, the condensed water separated out from the air can be collected through the chassis.

[0052] Refer to Figure 1 , the CO2 heat pump system 2, the phase change heat exchanger 3, and the water tank 4 are sequentially disposed in the housing 1 from top to bottom; or, in other embodiments, the CO2 heat pump system 2, the phase change heat exchanger 3, and the water tank 4 are sequentially disposed in the housing 1 along the length direction of the housing 1.

[0053] Moreover, when the CO2 heat pump system 2, the phase change heat exchanger 3, and the water tank 4 are sequentially arranged in the housing 1 from top to bottom, the air inlet 11 and the air outlet 12 are arranged at the top of the housing 1; when the CO2 heat pump system 2, the phase change heat exchanger 3, and the water tank 4 are sequentially arranged in the housing 1 along the length direction of the housing 1, the air inlet 11 and the air outlet 12 are arranged on the left side surface or the right side surface of the housing 1.

[0054] Embodiment 2

[0055] This embodiment provides a control method for a heat pump water heater, which is used to control the heat pump water heater in Embodiment 1. Refer to Figure 3 , and it includes the following steps:

[0056] S1: Obtain the ambient temperature, and obtain the heating capacity of the CO2 heat pump system 2 according to the ambient temperature and the ambient temperature - heating capacity data. Specifically, use the third temperature detector arranged at the air inlet 11 to detect the ambient temperature, and then obtain the heating capacity of the CO2 heat pump system 2 according to the ambient temperature and the ambient temperature - heating capacity data. The ambient temperature - heating capacity data is a database in which the ambient temperature and the heating capacity are in one-to-one correspondence. Therefore, the heating capacity corresponding to the ambient temperature can be determined through the ambient temperature.

[0057] S2: Obtain the heat of the hot water according to the historical hot water output volume and the historical hot water outlet temperature of the water tank 4. Specifically, use the first temperature detector arranged in the water tank 4 to detect the water temperature of the water tank 4, use the flow meter 42 arranged at the first water outlet 14 to obtain the historical hot water output volume, and then obtain the heat of the user's historical hot water according to the water temperature and the hot water output volume.

[0058] S3: Obtain the temperature of the water tank 4 and the temperature of the phase change heat exchanger 3. Specifically, use the first temperature detector arranged in the water tank 4 to detect the water temperature of the water tank 4, and use the second temperature detector arranged in the phase change heat exchanger 3 to detect the temperature of the phase change heat exchanger 3.

[0059] S4: When the heating capacity is greater than or equal to the heat of the hot water, determine whether the water temperature of the water tank and the phase change heat exchanger meet the conditions, and adopt the following hot water supply modes: (1) When the water temperature of the water tank 4 is greater than or equal to the temperature threshold and the temperature of the phase change heat exchanger 3 is less than the temperature threshold, use the water tank 4 to supply hot water; (2) When the water temperature of the water tank 4 is less than the temperature threshold and the temperature of the phase change heat exchanger 3 is greater than or equal to the temperature threshold, use the refrigerant circuit and the second refrigerant flow channel 31 to heat the water entering the second heat exchange flow channel 32 to supply hot water; (3) When the water temperature of the water tank 4 is greater than or equal to the temperature threshold and the temperature of the phase change heat exchanger 3 is greater than or equal to the temperature threshold, use the water tank 4 to supply hot water or use the refrigerant circuit and the second refrigerant flow channel 31 to heat the water entering the second heat exchange flow channel 32 to supply hot water; (4) When the water temperature of the water tank 4 is less than the temperature threshold and the temperature of the phase change heat exchanger 3 is less than the temperature threshold, determine the operation time of the power grid. When the operation time of the power grid is in the peak period, use the refrigerant circuit and the second refrigerant flow channel 31 to heat the water entering the second heat exchange flow channel 32 to supply hot water. When the operation time of the power grid is in the low valley period, use the refrigerant circuit to heat the water entering the first heat exchange flow channel 232 to supply hot water;

[0060] Or,

[0061] When the heating capacity is less than the heat of the hot water, determine the operation time of the power grid. When the operation time of the power grid is in the peak period, use the refrigerant circuit and the second refrigerant flow channel 31 to heat the water entering the second heat exchange flow channel 32 to supply hot water. When the operation time of the power grid is in the low valley period, use the refrigerant circuit to heat the water entering the first heat exchange flow channel 232 to supply hot water.

[0062] The above embodiments only represent the preferred embodiments of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and the present invention also intends to include these changes and modifications.

Claims

1. A heat pump water heater, characterized in that, Comprising: A housing, on which a first water inlet and a first water outlet are provided; A CO2 heat pump system, disposed within the housing, including a compressor, a plate heat exchanger, a throttling element, and an evaporator. A first refrigerant flow path and a first heat exchange flow path are thermally conducted within the plate heat exchanger. The compressor, the first refrigerant flow path, the throttling element, and the evaporator are sequentially connected by pipelines to form a refrigerant circuit; A water tank, disposed within the housing, having a second water inlet communicating with the first water inlet and a second water outlet communicating with the first water outlet. The water tank is connected to the first heat exchange flow path through a pipeline; A phase change heat exchanger, disposed within the housing, having a second refrigerant flow path, a second heat exchange flow path, and a phase change component. Both the second refrigerant flow path and the second heat exchange flow path are in contact with the phase change component. The second refrigerant flow path is connected in parallel with the first refrigerant flow path in the refrigerant circuit. The water inlet end of the second heat exchange flow path communicates with the first water inlet, and the water outlet end of the second heat exchange flow path communicates with the first water outlet; And a temperature detection assembly, and the temperature detection assembly includes a first temperature detector disposed within the water tank, a second temperature detector disposed within the phase change heat exchanger, and a third temperature detector disposed at any position capable of detecting the indoor air temperature entering the housing; And a control method for the above heat pump water heater, which includes the following steps: S1: Obtain the ambient temperature, and obtain the heating capacity of the CO2 heat pump system based on the ambient temperature and the ambient temperature - heating capacity data; S2: Obtain the heat of the hot water based on the historical hot water output volume and the historical hot water outlet temperature of the water tank; S3: Obtain the water temperature of the water tank and the temperature of the phase change heat exchanger; S4: When the heating capacity is greater than or equal to the heat of the hot water, determine whether the water temperature of the water tank and the phase change heat exchanger meet the conditions, and adopt the following hot water supply modes: (1) When the water temperature of the water tank is greater than or equal to the temperature threshold and the temperature of the phase change heat exchanger is less than the temperature threshold, use the water tank to supply hot water; (2) When the water temperature of the water tank is less than the temperature threshold and the temperature of the phase change heat exchanger is greater than or equal to the temperature threshold, heat the water entering the second heat exchange flow path using the refrigerant circuit and the second refrigerant flow path to supply hot water; (3) When the water temperature of the water tank is greater than or equal to the temperature threshold and the temperature of the phase change heat exchanger is greater than or equal to the temperature threshold, use the water tank to supply hot water or heat the water entering the second heat exchange flow path using the refrigerant circuit and the second refrigerant flow path to supply hot water; (4) When the water temperature of the water tank is less than the temperature threshold and the temperature of the phase change heat exchanger is less than the temperature threshold, determine the operation time of the power grid. When the operation time of the power grid is in the peak period, heat the water entering the second heat exchange flow path using the refrigerant circuit and the second refrigerant flow path to supply hot water. When the operation time of the power grid is in the low valley period, heat the water entering the first heat exchange flow path using the refrigerant circuit to supply hot water; Or, When the heating capacity is less than the heat of the hot water, the running time of the power grid is judged. And when the running time of the power grid is in the peak period, the refrigerant circuit and the second refrigerant flow path are used to heat the water entering the second heat exchange flow path to provide hot water. When the running time of the power grid is in the low valley period, the refrigerant circuit is used to heat the water entering the first heat exchange flow path to provide hot water.

2. The heat pump water heater according to claim 1, wherein A third water outlet is arranged on the water tank, and the third water outlet is communicated with the water inlet end of the second heat exchange flow path through a pipeline; a third solenoid valve is arranged on the pipeline between the third water outlet and the water inlet end of the second heat exchange flow path, and a fourth solenoid valve is arranged on the pipeline between the first water outlet and the second water outlet.

3. The heat pump water heater according to claim 1, wherein The refrigerant circuit further includes a first solenoid valve and a second solenoid valve. Two ends of the first solenoid valve are respectively communicated with the compressor and the inlet end of the first refrigerant flow path, and two ends of the second solenoid valve are respectively communicated with the compressor and the inlet end of the second refrigerant flow path.

4. The heat pump water heater according to claim 1, characterized in that, A flowmeter is arranged at the first water outlet.

5. The heat pump water heater according to claim 1, characterized in that, An air inlet and an air outlet are arranged on the outer shell. The CO2 heat pump system further includes a centrifugal fan arranged inside the outer shell. The centrifugal fan is used to drive the air located outside the outer shell to enter the outer shell through the air inlet and drive the air located inside the outer shell to flow out of the outer shell through the air outlet.

6. The heat pump water heater according to claim 5, wherein A third temperature detector is arranged at the air inlet.

7. The heat pump water heater according to claim 1, characterized in that, A partition board is arranged inside the outer shell. The partition board divides the cavity inside the outer shell into a first cavity and a second cavity. The CO2 heat pump system is arranged in the first cavity, the phase change heat exchanger and the water tank are arranged in the second cavity, and a heat insulation layer is arranged between the phase change heat exchanger and the water tank and the inner wall of the second cavity.

8. The heat pump water heater according to claim 7, characterized in that, A chassis is arranged at the bottom of the first cavity. The compressor, the plate heat exchanger and the evaporator are all connected to the chassis.

9. The heat pump water heater according to any one of claims 1-8, characterized in that, The CO2 heat pump system, the phase change heat exchanger and the water tank are arranged in the outer shell from top to bottom in sequence; or, the CO2 heat pump system, the phase change heat exchanger and the water tank are arranged in the outer shell in sequence along the length direction of the outer shell.

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