Heat pump water heater unit and control method thereof

Abstract

The application relates to a heat pump hot water unit and a control method thereof. The heat pump hot water unit comprises an inlet water pipe, an outlet water pipe, a refrigerant pipe, a water side heat exchanger, an air side heat exchanger, a compressor, a gas-liquid separator, an electronic expansion valve, a four-way valve, a plurality of temperature sensors and a controller. The plurality of temperature sensors are respectively arranged on the position of the second end of the refrigerant pipe close to the compressor, the first end of the refrigerant pipe, the inlet water pipe, the outlet water pipe and the water side heat exchanger. The plurality of temperature sensors, the compressor and the electronic expansion valve are electrically connected with the controller. In this way, the controller can judge the heat exchange efficiency of the water side heat exchanger according to the collected temperature value, and then control the working frequency of the compressor and / or the opening degree of the electronic expansion valve according to the heat exchange efficiency of the water side heat exchanger, so that the overall operation efficiency of the heat pump hot water unit is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat pump water heater units, in particular to a heat pump water heater unit and a control method thereof. BACKGROUND

[0002] In the operation process of the heat pump water heater unit, the refrigerant needs to be heat-exchanged in the water-side heat exchanger, and it usually needs to go through three stages of superheated state, saturated state and subcooled state in the heat exchange process. When the operating condition of the unit changes, the refrigerant is prone to no subcooling or excessive subcooling, which makes it difficult to maximize the operating efficiency of the unit. Therefore, how to improve the operating efficiency of the heat pump water heater unit has become a technical problem to be solved. SUMMARY

[0003] The present application provides a heat pump water heater unit and a control method thereof to solve the problem of low operating efficiency of the existing heat pump water heater unit.

[0004] In a first aspect, the present application provides a heat pump water heater unit, which comprises a water inlet pipe, a water outlet pipe, a refrigerant pipe, a water-side heat exchanger, an air-side heat exchanger, a compressor, a gas-liquid separator, an electronic expansion valve, a four-way valve, a plurality of temperature sensors and a controller.

[0005] The first end of the water-side heat exchanger is connected with the first end of the water inlet pipe and the first end of the refrigerant pipe respectively, and the second end of the water-side heat exchanger is connected with the second end of the water outlet pipe and the second end of the refrigerant pipe respectively.

[0006] The first end of the electronic expansion valve is connected with the first end of the water-side heat exchanger through the refrigerant pipe, the second end of the electronic expansion valve is connected with the first end of the air-side heat exchanger through the refrigerant pipe, the second end of the air-side heat exchanger is connected with the E end of the four-way valve through the refrigerant pipe, the S end of the four-way valve is connected with the first end of the gas-liquid separator through the refrigerant pipe, the second end of the gas-liquid separator is connected with the first end of the compressor through the refrigerant pipe, the second end of the compressor is connected with the D end of the four-way valve through the refrigerant pipe, and the C end of the four-way valve is connected with the second end of the water-side heat exchanger through the refrigerant pipe.

[0007] The plurality of temperature sensors are respectively arranged on the position close to the second end of the compressor of the refrigerant pipe, the first end of the refrigerant pipe, the water inlet pipe, the water outlet pipe and the water-side heat exchanger; and the plurality of temperature sensors, the compressor and the electronic expansion valve are respectively electrically connected with the controller.

[0008] Optionally, the plurality of temperature sensors comprises a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor, a fifth temperature sensor, and a sixth temperature sensor; the first temperature sensor, the second temperature sensor, the third temperature sensor, the fourth temperature sensor, the fifth temperature sensor, and the sixth temperature sensor are electrically connected to the controller respectively.

[0009] The first temperature sensor and the second temperature sensor are arranged on the water-side heat exchanger.

[0010] The third temperature sensor is arranged at a position close to the second end of the refrigerant pipe, and the fourth temperature sensor is arranged at a position close to the first end of the refrigerant pipe.

[0011] The fifth temperature sensor is arranged on the water inlet pipe, and the sixth temperature sensor is arranged on the water outlet pipe.

[0012] Optionally, the first temperature sensor is arranged at a position on the water-side heat exchanger at a first distance from the second end of the water-side heat exchanger, and the second temperature sensor is arranged at a position on the water-side heat exchanger at a second distance from the second end of the water-side heat exchanger.

[0013] The first distance is a distance corresponding to one-fifth to one-fourth of the total length of the water-side heat exchanger, and the second distance is a distance corresponding to one-third to one-half of the total length of the water-side heat exchanger.

[0014] Optionally, the plurality of temperature sensors further comprises a seventh temperature sensor and an eighth temperature sensor.

[0015] The seventh temperature sensor and the eighth temperature sensor are arranged on the air-side heat exchanger, and the seventh temperature sensor and the eighth temperature sensor are electrically connected to the controller respectively.

[0016] Optionally, the plurality of temperature sensors further comprises a ninth temperature sensor, the ninth temperature sensor is arranged at a position close to the first end of the refrigerant pipe, and the ninth temperature sensor is electrically connected to the controller.

[0017] Optionally, the heat pump water heater further comprises a low-pressure switch and a high-pressure switch.

[0018] The low-pressure switch is arranged at a position close to the first end of the refrigerant pipe, and the high-pressure switch is arranged at a position close to the second end of the refrigerant pipe, and the low-pressure switch and the high-pressure switch are electrically connected to the controller respectively.

[0019] Optionally, the heat pump water heater unit further comprises one or more filters, which are arranged on the refrigerant pipe between the first end of the water-side heat exchanger and the first end of the air-side heat exchanger.

[0020] Optionally, the heat pump water heater unit further comprises a fluorine injection nozzle, which is arranged on the refrigerant pipe between the second end of the air-side heat exchanger and the E end of the four-way valve.

[0021] In a second aspect, the present application provides a control method of a heat pump water heater unit, which is applied to the heat pump water heater unit of any one of the first aspect, and the method comprises:

[0022] The controller acquires temperature values collected by a plurality of temperature sensors respectively;

[0023] According to the temperature values, the working frequency of the compressor and / or the opening degree of the electronic expansion valve are controlled.

[0024] Optionally, the plurality of temperature sensors comprise a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor, a fifth temperature sensor and a sixth temperature sensor; wherein the first temperature sensor is used to detect the pipe initial temperature of the water-side heat exchanger, the second temperature sensor is used to detect the pipe medium temperature of the water-side heat exchanger, the third temperature sensor is used to detect the exhaust temperature of the compressor, the fourth temperature sensor is used to detect the out-pipe temperature of the water-side heat exchanger, the fifth temperature sensor is used to detect the inlet water temperature of the inlet water pipe, and the sixth temperature sensor is used to detect the outlet water temperature of the outlet water pipe.

[0025] According to the temperature values, the working frequency of the compressor and / or the opening degree of the electronic expansion valve are controlled, which comprises:

[0026] It is judged whether the out-pipe temperature is less than or equal to the sum of the inlet water temperature and a first temperature threshold value;

[0027] In the case that it is judged that the out-pipe temperature is less than or equal to the sum of the inlet water temperature and the first temperature threshold value, according to the pipe initial temperature, the outlet water temperature, the exhaust temperature and the pipe medium temperature, the working frequency of the compressor and / or the opening degree of the electronic expansion valve are controlled;

[0028] In the case that it is judged that the out-pipe temperature is greater than the sum of the inlet water temperature and the first temperature threshold value, according to the pipe medium temperature and the outlet water temperature, the working frequency of the compressor and / or the opening degree of the electronic expansion valve are controlled.

[0029] Optionally, the controlling the working frequency of the compressor and / or the opening degree of the electronic expansion valve according to the initial temperature of the pipe, the outlet water temperature, the exhaust temperature and the temperature in the pipe when it is determined that the outlet pipe temperature is less than or equal to the sum of the inlet water temperature and the first temperature threshold value comprises:

[0030] When it is determined that the outlet pipe temperature is less than or equal to the sum of the inlet water temperature and the first temperature threshold value, it is further determined whether the initial temperature of the pipe is less than or equal to the sum of the outlet water temperature and a second temperature threshold value, and whether the difference between the exhaust temperature and the outlet water temperature is greater than a third temperature threshold value and less than a fourth temperature threshold value;

[0031] When it is determined that the initial temperature of the pipe is less than or equal to the sum of the outlet water temperature and the second temperature threshold value, and the difference between the exhaust temperature and the outlet water temperature is less than or equal to the third temperature threshold value, the opening degree of the electronic expansion valve is reduced, and the working frequency of the compressor is reduced;

[0032] When it is determined that the initial temperature of the pipe is less than or equal to the sum of the outlet water temperature and the second temperature threshold value, and the difference between the exhaust temperature and the outlet water temperature is greater than or equal to the fourth temperature threshold value, the working frequency of the compressor is increased;

[0033] When it is determined that the initial temperature of the pipe is less than or equal to the sum of the outlet water temperature and the second temperature threshold value, and the difference between the exhaust temperature and the outlet water temperature is greater than the third temperature threshold value and less than the fourth temperature threshold value, the working frequency of the compressor is increased;

[0034] When it is determined that the initial temperature of the pipe is greater than the sum of the outlet water temperature and the second temperature threshold value, the working frequency of the compressor is controlled according to the temperature in the pipe and the outlet water temperature.

[0035] Optionally, the controlling the working frequency of the compressor according to the temperature in the pipe and the outlet water temperature when it is determined that the initial temperature of the pipe is greater than the sum of the outlet water temperature and the second temperature threshold value comprises:

[0036] When it is determined that the initial temperature of the pipe is greater than the sum of the outlet water temperature and the second temperature threshold value, it is further determined whether the temperature in the pipe is greater than or equal to the sum of the outlet water temperature and a fifth temperature threshold value, and less than or equal to the sum of the outlet water temperature and a sixth temperature threshold value;

[0037] When it is determined that the temperature in the pipe is less than the sum of the outlet water temperature and the fifth temperature threshold value, the working frequency of the compressor is increased;

[0038] maintain the operating frequency of the compressor unchanged when it is determined that the temperature in the pipe is greater than or equal to the sum of the outlet water temperature and the fifth temperature threshold value and less than or equal to the sum of the outlet water temperature and the sixth temperature threshold value;

[0039] decrease the operating frequency of the compressor when it is determined that the temperature in the pipe is greater than the sum of the outlet water temperature and the sixth temperature threshold value.

[0040] Optionally, the controlling the operating frequency of the compressor and / or the opening degree of the electronic expansion valve according to the temperature in the pipe and the outlet water temperature when it is determined that the outlet pipe temperature is greater than the sum of the inlet water temperature and the first temperature threshold value comprises:

[0041] further determining whether the temperature in the pipe is greater than the sum of the outlet water temperature and a seventh temperature threshold value when it is determined that the outlet pipe temperature is greater than the sum of the inlet water temperature and the first temperature threshold value;

[0042] decreasing the operating frequency of the compressor when it is determined that the temperature in the pipe is greater than the sum of the outlet water temperature and the seventh temperature threshold value;

[0043] decreasing the opening degree of the electronic expansion valve when it is determined that the temperature in the pipe is less than or equal to the sum of the outlet water temperature and the seventh temperature threshold value.

[0044] In a third aspect, the present application also provides a computer readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the control method of the heat pump water heater according to any one of the second aspect.

[0045] The heat pump water heater provided by the embodiments of the present application has the following advantages compared with the prior art: the heat pump water heater comprises an inlet water pipe, an outlet water pipe, a refrigerant pipe, a water-side heat exchanger, an air-side heat exchanger, a compressor, a gas-liquid separator, an electronic expansion valve, a four-way valve, a plurality of temperature sensors and a controller;

[0046] The first end of the water-side heat exchanger is connected with the first end of the inlet water pipe and the first end of the refrigerant pipe respectively, and the second end of the water-side heat exchanger is connected with the second end of the outlet water pipe and the second end of the refrigerant pipe respectively.

[0047] The first end of the electronic expansion valve is connected with the first end of the water-side heat exchanger through the refrigerant pipe, the second end of the electronic expansion valve is connected with the first end of the air-side heat exchanger through the refrigerant pipe, the second end of the air-side heat exchanger is connected with the E end of the four-way valve through the refrigerant pipe, the S end of the four-way valve is connected with the first end of the gas-liquid separator through the refrigerant pipe, the second end of the gas-liquid separator is connected with the first end of the compressor through the refrigerant pipe, the second end of the compressor is connected with the D end of the four-way valve through the refrigerant pipe, and the C end of the four-way valve is connected with the second end of the water-side heat exchanger through the refrigerant pipe.

[0048] The plurality of temperature sensors are arranged on positions close to the second end of the compressor, the first end of the refrigerant pipe, the water inlet pipe, the water outlet pipe and the water-side heat exchanger, and are electrically connected with the controller. In this way, the temperatures of the refrigerant at the positions close to the second end of the compressor, the first end of the refrigerant pipe and the water-side heat exchanger, and the temperatures of the water in the water inlet pipe and the water outlet pipe can be collected by the plurality of temperature sensors, and the collected temperature values can be sent to the controller. Thus, the controller can determine the heat exchange efficiency of the water-side heat exchanger according to the collected temperature values, and control the working frequency of the compressor and / or the opening degree of the electronic expansion valve according to the heat exchange efficiency of the water-side heat exchanger, so that the overall operation efficiency of the heat pump water heater is improved. BRIEF DESCRIPTION OF DRAWINGS

[0049] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments consistent with the present application and, together with the description, further serve to explain the principles of the application.

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced here. Obviously, for those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0051] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings, which do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, unless otherwise specified. The drawings do not constitute a proportional limitation.

[0052] Figure 1 A structure schematic diagram of a heat pump water heater provided by an embodiment of the present application;

[0053] Figure 2 Another structure schematic diagram of a heat pump water heater provided by an embodiment of the present application;

[0054] Figure 3 A flowchart of a control method of a heat pump water heater unit is provided for the embodiments of the present application.

[0055] Wherein, 110, water inlet pipe; 120, water outlet pipe; 130, refrigerant pipe; 140, water side heat exchanger; 150, air side heat exchanger; 160, compressor; 170, gas-liquid separator; 180, electronic expansion valve; 190, four-way valve; 200, temperature sensor; 250, controller; 201, first temperature sensor; 202, second temperature sensor; 203, third temperature sensor; 204, fourth temperature sensor; 205, fifth temperature sensor; 206, sixth temperature sensor; 207, seventh temperature sensor; 208, eighth temperature sensor; 209, ninth temperature sensor; 210, low pressure switch; 220, high pressure switch; 230, filter; 240, fluorine injection nozzle. DETAILED DESCRIPTION

[0056] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0057] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplification, the components and arrangements of the specific examples are described in the following. Of course, they are only examples and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to the numbers and / or letters in different examples. Such repetition is for the purpose of simplification and clarity, and does not indicate the relationship between the various embodiments and / or arrangements discussed.

[0058] In order to solve the technical problem of low operating efficiency of the heat pump water heater unit in the prior art, the present application provides a heat pump water heater unit and a control method thereof, which can improve the operating efficiency of the heat pump water heater unit.

[0059] Referring to Figure 1 and Figure 2 , Figure 1 and Figure 2 The structural diagram of the heat pump water heater unit provided for the embodiments of the present application is shown in FIG. 1. As shown in FIG. 1, the heat pump water heater unit comprises a compressor 160, a gas-liquid separator 170, an electronic expansion valve 180, a four-way valve 190, a water side heat exchanger 140, an air side heat exchanger 150, a water inlet pipe 110, a water outlet pipe 120, a refrigerant pipe 130, a temperature sensor 200, and a controller 250. Figure 1As shown, the heat pump water heater unit includes a water inlet pipe 110, a water outlet pipe 120, a refrigerant pipe 130, a water-side heat exchanger 140, an air-side heat exchanger 150, a compressor 160, a gas-liquid separator 170, an electronic expansion valve 180, a four-way valve 190, a plurality of temperature sensors 200, and a controller 250 (not shown); Figure 1

[0060] The first end of the water-side heat exchanger 140 is connected to the first end of the water inlet pipe 110 and the refrigerant pipe 130, respectively, and the second end of the water-side heat exchanger 140 is connected to the second end of the water outlet pipe 120 and the refrigerant pipe 130, respectively.

[0061] The first end of the electronic expansion valve 180 is connected to the first end of the water-side heat exchanger 140 through the refrigerant pipe 130, the second end of the electronic expansion valve 180 is connected to the first end of the air-side heat exchanger 150 through the refrigerant pipe 130, the second end of the air-side heat exchanger 150 is connected to the E end of the four-way valve 190 through the refrigerant pipe 130, the S end of the four-way valve 190 is connected to the first end of the gas-liquid separator 170 through the refrigerant pipe 130, the second end of the gas-liquid separator 170 is connected to the first end of the compressor 160 through the refrigerant pipe 130, the second end of the compressor 160 is connected to the D end of the four-way valve 190 through the refrigerant pipe 130, and the C end of the four-way valve 190 is connected to the second end of the water-side heat exchanger 140 through the refrigerant pipe 130.

[0062] The plurality of temperature sensors 200 are arranged on the refrigerant pipe 130 near the second end of the compressor 160, the first end of the refrigerant pipe 130, the water inlet pipe 110, the water outlet pipe 120, and the water-side heat exchanger 140, respectively. The plurality of temperature sensors 200, the compressor 160, and the electronic expansion valve 180 are electrically connected to the controller 250, respectively.

[0063] Specifically, the water-side heat exchanger 140 is used for heat exchange between refrigerant and water, and the air-side heat exchanger 150 is used for heat exchange between refrigerant and air. For example, taking the heat pump water heater unit in a heating operation mode as an example, the heat pump water heater unit first transfers the heat energy in the air to the refrigerant through the air-side heat exchanger 150, the refrigerant is compressed by the compressor 160 to form high-temperature and high-pressure refrigerant, and then flows through the water-side heat exchanger 140 to exchange heat with water, so that the heat energy in the refrigerant is transferred to the water in the water-side heat exchanger 140 to obtain hot water. The low-temperature and low-pressure refrigerant flowing out of the water-side heat exchanger 140 flows into the air-side heat exchanger 150 again for heat exchange, and the cycle is repeated to realize the heating operation.

[0064] ​The plurality of temperature sensors 200 are respectively arranged at positions close to the second end of the compressor 160 of the refrigerant pipe 130, the first end of the refrigerant pipe 130, the water inlet pipe 110, the water outlet pipe 120 and the water-side heat exchanger 140. That is, the refrigerant temperature at the second end of the compressor 160, the refrigerant temperature at the first end of the refrigerant pipe 130, the water temperature in the water inlet pipe 110, the water temperature in the water outlet pipe 120 and the refrigerant temperature in the water-side heat exchanger 140 can be collected by using the plurality of temperature sensors 200. In this way, the controller 250 can obtain the temperature values collected by the plurality of temperature sensors 200, and determine the heat exchange efficiency of the water-side heat exchanger 140 according to the collected temperature values, and then control the working frequency of the compressor 160 and / or the opening degree of the electronic expansion valve 180 according to the heat exchange efficiency of the water-side heat exchanger 140, so that the overall operation efficiency of the heat pump water heater unit is improved.

[0065] It should be noted that the number of temperature sensors arranged on the water-side heat exchanger 140 can be one or multiple, and when multiple, the refrigerant temperatures at different positions of the water-side heat exchanger 140 can be collected. In the embodiments of the present application, the number and position of the temperature sensors on the water-side heat exchanger 140 can be set according to actual needs, which is not limited in the embodiments of the present application.

[0066] Further, continuing to refer to Figure 1 , the plurality of temperature sensors 200 include a first temperature sensor 201, a second temperature sensor 202, a third temperature sensor 203, a fourth temperature sensor 204, a fifth temperature sensor 205 and a sixth temperature sensor 206; the first temperature sensor 201, the second temperature sensor 202, the third temperature sensor 203, the fourth temperature sensor 204, the fifth temperature sensor 205 and the sixth temperature sensor 206 are respectively electrically connected with the controller 250;

[0067] The first temperature sensor 201 and the second temperature sensor 202 are arranged on the water-side heat exchanger 140;

[0068] The third temperature sensor 203 is arranged at a position close to the second end of the compressor 160 of the refrigerant pipe 130, and the fourth temperature sensor 204 is arranged at a position close to the first end of the refrigerant pipe 130;

[0069] The fifth temperature sensor 205 is arranged on the water inlet pipe 110, and the sixth temperature sensor 206 is arranged on the water outlet pipe 120.

[0070] Specifically, the first temperature sensor 201 can be used to detect the tube initial temperature of the water-side heat exchanger 140 (i.e., the temperature of the refrigerant at a position close to the second end of the water-side heat exchanger 140 in the water-side heat exchanger 140), the second temperature sensor 202 can be used to detect the tube middle temperature of the water-side heat exchanger 140 (i.e., the temperature of the refrigerant at a position close to the middle of the water-side heat exchanger 140 in the water-side heat exchanger 140), the third temperature sensor 203 can be used to detect the discharge temperature of the compressor 160 (i.e., the temperature of the gaseous refrigerant after being compressed by the compressor 160), the fourth temperature sensor 204 can be used to detect the tube outlet temperature of the water-side heat exchanger 140 (i.e., the temperature of the refrigerant after being heat-exchanged by the water-side heat exchanger 140), the fifth temperature sensor 205 can be used to detect the inlet water temperature of the inlet water pipe 110 (i.e., the temperature of the water before being heat-exchanged by the water-side heat exchanger 140), and the sixth temperature sensor 206 can be used to detect the outlet water temperature of the outlet water pipe 120 (i.e., the temperature of the water after being heat-exchanged by the water-side heat exchanger 140). In this way, the controller 250 can collect the tube initial temperature, the tube middle temperature, the discharge temperature, the tube outlet temperature, the inlet water temperature, and the outlet water temperature by using the plurality of temperature sensors 200, determine the heat exchange efficiency of the water-side heat exchanger 140, and then control the working frequency of the compressor 160 and / or the opening degree of the electronic expansion valve 180 according to the heat exchange efficiency of the water-side heat exchanger 140, so that the overall operation efficiency of the heat pump water heater unit is improved. Specifically, the controller 250 can first determine whether the tube outlet temperature is less than or equal to the sum of the inlet water temperature and a first temperature threshold. In the case where it is determined that the tube outlet temperature is less than or equal to the sum of the inlet water temperature and the first temperature threshold, it indicates that the heat exchange of the refrigerant in the water-side heat exchanger 140 is sufficient. At this time, the controller 250 can further determine whether there is other optimization space for the heat pump water heater unit according to the tube initial temperature, the outlet water temperature, the discharge temperature, and the tube middle temperature, and control the working frequency of the compressor 160 and / or the opening degree of the electronic expansion valve 180 according to the determination result, so as to improve the overall operation efficiency of the heat pump water heater unit. In the case where it is determined that the tube outlet temperature is greater than the sum of the inlet water temperature and the first temperature threshold, it indicates that the heat exchange of the refrigerant in the water-side heat exchanger 140 is not sufficient. At this time, the controller 250 can further determine the reason why the heat exchange of the refrigerant in the water-side heat exchanger 140 is not sufficient according to the tube middle temperature and the outlet water temperature, and then control the working frequency of the compressor 160 and / or the opening degree of the electronic expansion valve 180 according to the determination result, so as to improve the overall operation efficiency of the heat pump water heater unit.

[0071] Further, with reference to Figure 1 , the first temperature sensor 201 is arranged on the water-side heat exchanger 140 at a first distance from the second end of the water-side heat exchanger 140, and the second temperature sensor 202 is arranged on the water-side heat exchanger 140 at a second distance from the second end of the water-side heat exchanger 140;

[0072] The first distance is the distance corresponding to one-fifth to one-quarter of the total length of the water-side heat exchanger 140, and the second distance is the distance corresponding to one-third to one-half of the total length of the water-side heat exchanger 140.

[0073] Specifically, the first distance and the second distance mentioned above can be set according to actual conditions, and this application embodiment does not impose specific limitations.

[0074] In one embodiment, the first distance corresponds to one-fifth to one-quarter of the total length of the water-side heat exchanger 140, and the second distance corresponds to one-third to one-half of the total length of the water-side heat exchanger 140. That is, the first temperature sensor 201 is located at 1 / 5 to 1 / 4 of the total length of the water-side heat exchanger 140, and the second temperature sensor 202 is located at 1 / 3 to 1 / 2 of the total length of the water-side heat exchanger 140. The advantage of this arrangement is that since the refrigerant undergoes three states within the water-side heat exchanger 140—superheated, saturated, and subcooled—arranging four temperature sensors on and before and after the water-side heat exchanger 140 to detect the exhaust temperature, inlet pipe temperature, pipe temperature, and outlet pipe temperature allows for accurate monitoring of the refrigerant temperature before and after each state, effectively controlling hardware costs while ensuring data accuracy.

[0075] Further, see also Figure 1 The multiple temperature sensors 200 include a seventh temperature sensor 207 and an eighth temperature sensor 208;

[0076] The seventh temperature sensor 207 and the eighth temperature sensor 208 are both mounted on the air-side heat exchanger 150, and are electrically connected to the controller 250.

[0077] In one embodiment, in addition to setting a temperature sensor on the water-side heat exchanger 140, a seventh temperature sensor 207 and an eighth temperature sensor 208 can also be set on the air-side heat exchanger 150. The ambient temperature is obtained through the seventh temperature sensor 207 and the outdoor pipe temperature is obtained through the eighth temperature sensor 208. In this way, the controller 250 can determine the heat exchange efficiency of the air-side heat exchanger 150 based on the obtained ambient temperature and outdoor pipe temperature, and then control the operating frequency of the compressor 160 and / or the opening degree of the electronic expansion valve 180 in combination with the heat exchange efficiency of the water-side heat exchanger 140.

[0078] Further, see also Figure 1The plurality of temperature sensors 200 further include a ninth temperature sensor 209 disposed at a position of the refrigerant pipe 130 close to the first end of the compressor 160, and the ninth temperature sensor 209 is electrically connected to the controller 250.

[0079] In an embodiment, a ninth temperature sensor 209 can also be disposed at a position of the refrigerant pipe 130 close to the first end of the compressor 160, and the suction temperature, i.e. the temperature of the refrigerant sucked into the compressor 160, is obtained by the ninth temperature sensor 209. In this way, the controller 250 can determine the compression efficiency of the compressor 160 according to the obtained suction temperature and discharge temperature, and then control the working frequency of the compressor 160.

[0080] Further, referring to Figure 1 , the heat pump water heater further includes a low-pressure switch 210 and a high-pressure switch 220.

[0081] The low-pressure switch 210 is disposed at a position of the refrigerant pipe 130 close to the first end of the compressor 160, and the high-pressure switch 220 is disposed at a position of the refrigerant pipe 130 close to the second end of the compressor 160. The low-pressure switch 210 and the high-pressure switch 220 are electrically connected to the controller 250.

[0082] In an embodiment, the low-pressure switch 210 can be disposed at a position of the refrigerant pipe 130 close to the first end of the compressor 160, and the high-pressure switch 220 can be disposed at a position of the refrigerant pipe 130 close to the second end of the compressor 160. That is, the high-pressure switch 220 is disposed on the pipeline between the discharge port of the compressor 160 and the four-way valve 190, and the low-pressure switch 210 is disposed on the pipeline between the gas-liquid separator 170 and the suction port of the compressor 160. When the discharge pressure of the compressor 160 is higher than a specified value, the high-pressure switch 220 is turned off. When the suction pressure of the compressor 160 is lower than a specified value, the low-pressure switch 210 is turned off. The turned-off pressure switch gives an on-off signal to the controller 250 to control the compressor 160 to stop working, thereby protecting the compressor 160.

[0083] Further, referring to Figure 1 , the heat pump water heater further includes one or more filters 230 disposed on the refrigerant pipe 130 between the first end of the water-side heat exchanger 140 and the first end of the air-side heat exchanger 150.

[0084] In an embodiment, one or more filters 230 can also be arranged on the refrigerant pipe 130 between the first end of the water-side heat exchanger 140 and the first end of the air-side heat exchanger 150. The one or more filters 230 can have the following functions: 1) liquid storage function: the liquid storage function is used to store and supply liquid refrigerant in the heat pump water heater unit, so as to compensate and adjust the gain and loss of the liquid refrigerant when the working condition changes; 2) filtering function: when the pipeline is installed, it is possible that dirt is brought in inadvertently, and dirt such as oxide scale can be produced in the pipeline. The dirt can be removed by filtering, so as to ensure the smooth flow of the refrigerant and prevent the normal work from being affected due to blockage; and 3) drying function: the drying function is used to absorb the moisture in the refrigerant, so as to avoid causing "water blockage".

[0085] Further, with reference to Figure 1 , the heat pump water heater unit further comprises a fluorine injection nozzle 240 arranged on the refrigerant pipe 130 between the second end of the air-side heat exchanger 150 and the E end of the four-way valve 190.

[0086] In an embodiment, the fluorine injection nozzle 240 can also be arranged on the refrigerant pipe 130 between the second end of the air-side heat exchanger 150 and the E end of the four-way valve 190. The fluorine injection nozzle 240 is used to supplement the refrigerant in the refrigerant pipe 130 in time, so as to ensure the normal operation of the heat pump water heater unit.

[0087] With reference to Figure 3 , Figure 3 A flowchart of a control method of a heat pump water heater unit according to an embodiment of the present application is provided. As shown in Figure 3 , the control method of the heat pump water heater unit is applied to the heat pump water heater unit of any of the foregoing embodiments. The method comprises the following steps:

[0088] In step 301, the controller acquires temperature values collected by a plurality of temperature sensors.

[0089] In step 302, the working frequency of the compressor and / or the opening degree of the electronic expansion valve are controlled according to the temperature values.

[0090] In an embodiment, the plurality of temperature sensors are arranged on the refrigerant pipe close to the second end of the compressor, the first end of the refrigerant pipe, the water inlet pipe, the water outlet pipe and the water-side heat exchanger. That is, the refrigerant temperature at the second end of the compressor, the refrigerant temperature at the first end of the refrigerant pipe, the water temperature in the water inlet pipe, the water temperature in the water outlet pipe and the refrigerant temperature in the water-side heat exchanger can be collected by the plurality of temperature sensors. In this way, the controller can acquire the temperature values collected by the plurality of temperature sensors, and determine the heat exchange efficiency of the water-side heat exchanger according to the collected temperature values. Then, the working frequency of the compressor and / or the opening degree of the electronic expansion valve are controlled according to the heat exchange efficiency of the water-side heat exchanger, so that the overall operation efficiency of the heat pump water heater unit is improved.

[0091] Further, the plurality of temperature sensors comprise a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor, a fifth temperature sensor and a sixth temperature sensor; wherein the first temperature sensor is configured to detect a pipe initial temperature of the water-side heat exchanger, the second temperature sensor is configured to detect a pipe middle temperature of the water-side heat exchanger, the third temperature sensor is configured to detect a discharge temperature of the compressor, the fourth temperature sensor is configured to detect a pipe outlet temperature of the water-side heat exchanger, the fifth temperature sensor is configured to detect a water inlet temperature of a water inlet pipe, and the sixth temperature sensor is configured to detect a water outlet temperature of a water outlet pipe.

[0092] The step 301 further comprises:

[0093] determining whether the pipe temperature is less than or equal to the sum of the water inlet temperature and a first temperature threshold value;

[0094] In a case where it is determined that the pipe temperature is less than or equal to the sum of the water inlet temperature and the first temperature threshold value, the working frequency of the compressor and / or the opening degree of the electronic expansion valve are controlled according to the pipe initial temperature, the water outlet temperature, the discharge temperature and the pipe middle temperature.

[0095] In a case where it is determined that the pipe temperature is greater than the sum of the water inlet temperature and the first temperature threshold value, the working frequency of the compressor and / or the opening degree of the electronic expansion valve are controlled according to the pipe middle temperature and the water outlet temperature.

[0096] In an embodiment, the controller can first determine whether the pipe temperature is less than or equal to the sum of the water inlet temperature and the first temperature threshold value, and in a case where it is determined that the pipe temperature is less than or equal to the sum of the water inlet temperature and the first temperature threshold value, it indicates that the heat exchange of the refrigerant in the water-side heat exchanger is sufficient, at this time, the controller can further determine whether there is other optimization space for the heat pump water heater unit according to the pipe initial temperature, the water outlet temperature, the discharge temperature and the pipe middle temperature, and control the working frequency of the compressor and / or the opening degree of the electronic expansion valve according to the determination result, so as to improve the overall operation efficiency of the heat pump water heater unit. In a case where it is determined that the pipe temperature is greater than the sum of the water inlet temperature and the first temperature threshold value, it indicates that the heat exchange of the refrigerant in the water-side heat exchanger is not sufficient, at this time, the controller can further determine the reason why the heat exchange of the refrigerant in the water-side heat exchanger is not sufficient according to the pipe middle temperature and the water outlet temperature, and then control the working frequency of the compressor and / or the opening degree of the electronic expansion valve according to the determination result, so as to improve the overall operation efficiency of the heat pump water heater unit.

[0097] Further, in a case where it is determined that the pipe temperature is less than or equal to the sum of the water inlet temperature and the first temperature threshold value, the working frequency of the compressor and / or the opening degree of the electronic expansion valve are controlled according to the pipe initial temperature, the water outlet temperature, the discharge temperature and the pipe middle temperature.

[0098] In the case of determining that the pipe temperature is less than or equal to the sum of the inlet water temperature and the first temperature threshold, it is further determined whether the pipe initial temperature is less than or equal to the sum of the outlet water temperature and the second temperature threshold, and whether the difference between the exhaust temperature and the outlet water temperature is greater than the third temperature threshold and less than the fourth temperature threshold;

[0099] In the case of determining that the pipe initial temperature is less than or equal to the sum of the outlet water temperature and the second temperature threshold, and the difference between the exhaust temperature and the outlet water temperature is less than or equal to the third temperature threshold, the opening of the electronic expansion valve is reduced, and the operating frequency of the compressor is reduced;

[0100] In the case of determining that the pipe initial temperature is less than or equal to the sum of the outlet water temperature and the second temperature threshold, and the difference between the exhaust temperature and the outlet water temperature is greater than or equal to the fourth temperature threshold, the operating frequency of the compressor is increased;

[0101] In the case of determining that the pipe initial temperature is less than or equal to the sum of the outlet water temperature and the second temperature threshold, and the difference between the exhaust temperature and the outlet water temperature is greater than the third temperature threshold and less than the fourth temperature threshold, the operating frequency of the compressor is increased;

[0102] In the case of determining that the pipe initial temperature is greater than the sum of the outlet water temperature and the second temperature threshold, the operating frequency of the compressor is controlled according to the temperature in the pipe and the outlet water temperature.

[0103] Specifically, the first temperature threshold, the second temperature threshold, the third temperature threshold and the fourth temperature threshold can be set according to actual needs, and the embodiments of the present application are not limited specifically. The first temperature threshold, the second temperature threshold and the third temperature threshold can be the same or different, and the third temperature threshold is less than the fourth temperature threshold.

[0104] In an embodiment, when it is determined that the tube temperature is less than or equal to the sum of the water inlet temperature and the first temperature threshold, it indicates that the heat exchange of the refrigerant in the water-side heat exchanger is sufficient. At this time, it can be further determined whether the tube initial temperature is less than or equal to the sum of the water outlet temperature and the second temperature threshold, and whether the difference between the exhaust temperature and the water outlet temperature is greater than the third temperature threshold and less than the fourth temperature threshold. When it is determined that the tube initial temperature is less than or equal to the sum of the water outlet temperature and the second temperature threshold, and the difference between the exhaust temperature and the water outlet temperature is less than or equal to the third temperature threshold, it can be considered that the unit has a risk of liquid return, and at this time the opening of the electronic expansion valve needs to be reduced, and the working frequency of the compressor also needs to be reduced. Because the high-temperature superheated gaseous refrigerant discharged by the compressor enters the water-side heat exchanger to undergo three state changes, if the tube initial temperature is less than or equal to the sum of the water outlet temperature and the second temperature threshold, it indicates that the refrigerant heat is almost exhausted at the initial position, and is in a saturated state or a liquid state. The initial position is at the front end, and the low temperature at this position indicates that the compressor discharge enthalpy is low, and the refrigerant temperature is cooled after a small amount of heat exchange. The reason for the low compressor discharge enthalpy is two-fold: the first is suction liquid carrying, and the second is low compressor working frequency. Another feature of suction liquid carrying is that the exhaust temperature is low (i.e., the difference between the exhaust temperature and the water outlet temperature is less than or equal to the third temperature threshold), so if the tube initial temperature is less than or equal to the sum of the water outlet temperature and the second temperature threshold, and the difference between the exhaust temperature and the water outlet temperature is less than or equal to the third temperature threshold, it can be considered that the reason for the low compressor discharge enthalpy is suction liquid carrying.

[0105] When it is determined that the tube initial temperature is less than or equal to the sum of the water outlet temperature and the second temperature threshold, and the difference between the exhaust temperature and the water outlet temperature is greater than or equal to the fourth temperature threshold, it indicates that the compressor discharge enthalpy is low, but due to the high compressor exhaust temperature, it can be considered that the reason for the low compressor discharge enthalpy is low compressor working frequency, and the water-side heat exchanger is operating at a very low load. It is necessary to speed up the compressor frequency increase speed to improve the utilization rate of the water-side heat exchanger. If there is no frequency increase requirement at this time, the outdoor fan operating frequency can also be reduced to improve the overall operating efficiency of the unit.

[0106] When it is determined that the tube initial temperature is less than or equal to the sum of the water outlet temperature and the second temperature threshold, and the difference between the exhaust temperature and the water outlet temperature is greater than the third temperature threshold and less than the fourth temperature threshold, it indicates that the heat pump water heater is currently between the above two situations, and is in a relatively ideal state. At this time, the water-side heat exchanger still has utilization space, and the working frequency of the compressor can be further increased. If there is no frequency increase requirement, the current state can be maintained unchanged.

[0107] When it is determined that the tube initial temperature is greater than the sum of the water outlet temperature and the second temperature threshold, the working frequency of the compressor needs to be controlled according to the tube temperature and the water outlet temperature at this time.

[0108] In an embodiment, when the refrigerant has been sufficiently exchanged in the water-side heat exchanger, the controller can further determine whether there is any other optimization space for the heat pump water heater unit according to the pipe initial temperature, the outlet water temperature, the exhaust temperature and the pipe temperature, and control the working frequency of the compressor and / or the opening degree of the electronic expansion valve according to the determination result, so as to improve the overall operation efficiency of the heat pump water heater unit.

[0109] Further, the step of controlling the working frequency of the compressor according to the pipe temperature and the outlet water temperature when it is determined that the pipe initial temperature is greater than the sum of the outlet water temperature and the second temperature threshold value, comprises:

[0110] when it is determined that the pipe initial temperature is greater than the sum of the outlet water temperature and the second temperature threshold value, further determining whether the pipe temperature is greater than or equal to the sum of the outlet water temperature and the fifth temperature threshold value and less than or equal to the sum of the outlet water temperature and the sixth temperature threshold value;

[0111] when it is determined that the pipe temperature is less than the sum of the outlet water temperature and the fifth temperature threshold value, increasing the working frequency of the compressor;

[0112] when it is determined that the pipe temperature is greater than or equal to the sum of the outlet water temperature and the fifth temperature threshold value and less than or equal to the sum of the outlet water temperature and the sixth temperature threshold value, maintaining the working frequency of the compressor unchanged;

[0113] when it is determined that the pipe temperature is greater than the sum of the outlet water temperature and the sixth temperature threshold value, reducing the working frequency of the compressor.

[0114] Specifically, the fifth temperature threshold value and the sixth temperature threshold value can be set according to actual needs, and the embodiments of the present application are not limited specifically. The fifth temperature threshold value is less than the sixth temperature threshold value.

[0115] It should be noted that the pipe temperature should be approximately the saturation temperature of the refrigerant in the water-side heat exchanger under normal circumstances. The high saturation temperature indicates that the operation pressure is high, which is caused by insufficient heat exchange. The low saturation temperature indicates that the operation pressure is low, which is caused by too small load.

[0116] In an embodiment, when the pipe initial temperature is greater than the sum of the outlet water temperature and the second temperature threshold, it can be further determined whether the temperature in the pipe is greater than or equal to the sum of the outlet water temperature and the fifth temperature threshold and less than or equal to the sum of the outlet water temperature and the sixth temperature threshold. If it is determined that the temperature in the pipe is less than the sum of the outlet water temperature and the fifth temperature threshold, it can be considered that there is still room for the water-side heat exchanger, allowing the compressor frequency to continue to increase, and if there is no need to increase the frequency, the current state can be maintained unchanged. If it is determined that the temperature in the pipe is greater than or equal to the sum of the outlet water temperature and the fifth temperature threshold and less than or equal to the sum of the outlet water temperature and the sixth temperature threshold, it can be considered that the water-side heat exchanger is in a reasonable state, and the working frequency of the compressor is maintained unchanged. If it is determined that the temperature in the pipe is greater than the sum of the outlet water temperature and the sixth temperature threshold, it can be considered that the water-side heat exchanger is operating at a relatively high pressure, and the working frequency of the compressor needs to be reduced.

[0117] Further, the above step, in the case of determining that the pipe temperature is greater than the sum of the inlet water temperature and the first temperature threshold, the working frequency of the compressor and / or the opening degree of the electronic expansion valve are controlled according to the temperature in the pipe and the outlet water temperature, comprising:

[0118] In the case of determining that the pipe temperature is greater than the sum of the inlet water temperature and the first temperature threshold, it is further determined whether the temperature in the pipe is greater than the sum of the outlet water temperature and the seventh temperature threshold.

[0119] In the case of determining that the temperature in the pipe is greater than the sum of the outlet water temperature and the seventh temperature threshold, the working frequency of the compressor is reduced.

[0120] In the case of determining that the temperature in the pipe is less than or equal to the sum of the outlet water temperature and the seventh temperature threshold, the opening degree of the electronic expansion valve is reduced.

[0121] Specifically, the above-mentioned seventh temperature threshold can be set according to actual needs, and the embodiments of the present application are not limited.

[0122] In an embodiment, in the case of determining that the pipe temperature is greater than the sum of the inlet water temperature and the first temperature threshold, it indicates that the refrigerant is not fully heat-exchanged in the water-side heat exchanger, at this time, the controller can further determine the reason why the refrigerant is not fully heat-exchanged in the water-side heat exchanger according to the temperature in the pipe and the outlet water temperature. Specifically, if it is determined that the temperature in the pipe is greater than the sum of the outlet water temperature and the seventh temperature threshold, it can be considered that the water-side heat exchanger is operating at a relatively high pressure, at this time, the working frequency of the compressor needs to be reduced to improve the operating efficiency of the heat pump water heater unit. If it is determined that the temperature in the pipe is less than or equal to the sum of the outlet water temperature and the seventh temperature threshold, it can be considered that the opening degree of the electronic expansion valve is too large, and the condensing pressure is insufficient, at this time, the opening degree of the electronic expansion valve needs to be reduced to improve the overall operating efficiency of the heat pump water heater unit.

[0123] In an embodiment, one temperature sensor can be arranged at the initial position of the water side heat exchanger, and one temperature sensor can be arranged at the middle position of the water side heat exchanger, the initial position is at 1 / 5-1 / 4 of the total length of the water side heat exchanger, and the middle position is at 1 / 3-1 / 2 of the total length of the water side heat exchanger.

[0124] When the outlet pipe temperature is less than or equal to the inlet water temperature plus 2℃, it is indicated that the heat exchange of the refrigerant in the water side heat exchanger is sufficient. At this time, if the initial pipe temperature is less than or equal to the outlet water temperature plus 5℃ and the exhaust temperature minus the outlet water temperature is less than or equal to 10℃, it is considered that the unit has a risk of backflow, and the electronic expansion valve needs to be closed immediately, and the working frequency of the compressor needs to be reduced. If the initial pipe temperature is less than or equal to the outlet water temperature plus 5℃ and the exhaust temperature minus the outlet water temperature is greater than 40℃, it is considered that the water side heat exchanger is running at a very low load, and the compressor frequency increasing speed needs to be accelerated to improve the use rate of the heat exchanger. If there is no need to increase the frequency at this time, the outdoor fan operating frequency can be reduced to improve the operating efficiency of the whole machine. If the initial pipe temperature is less than or equal to the outlet water temperature plus 5℃ and 10 < the exhaust temperature minus the outlet water temperature < 40℃, it is considered that the water side heat exchanger still has utilization space, and the compressor frequency can be continued to be increased. If there is no need to increase the frequency, the state can be maintained. If the initial pipe temperature is greater than the outlet water temperature plus 5℃, the pipe temperature needs to be judged. If the pipe temperature is less than or equal to the outlet water temperature plus 2℃, it is considered that the water side heat exchanger still has utilization space, and the compressor frequency can be continued to be increased. If there is no need to increase the frequency, the state can be maintained. If the outlet water temperature plus 2℃ < the pipe temperature < the outlet water temperature plus 5℃, it is considered that the state of the water side heat exchanger is reasonable. If the pipe temperature is greater than the outlet water temperature plus 5℃, it is considered that the water side heat exchanger runs at a high pressure, and the compressor frequency can be reduced to improve the operating efficiency.

[0125] When the outlet pipe temperature is greater than the inlet water temperature plus 2℃, it is indicated that the heat exchange of the refrigerant in the water side heat exchanger is not sufficient.

[0126] At this time, if the pipe temperature is greater than the outlet water temperature plus 5℃, it is considered that the water side heat exchanger runs at a high pressure, and the compressor frequency can be reduced to improve the operating efficiency. If the pipe temperature is less than or equal to the outlet water temperature plus 5℃, it is considered that the opening degree of the electronic expansion valve is too large, and the condensing pressure is insufficient, and the opening degree of the electronic expansion valve needs to be reduced.

[0127] In the embodiment, the working state of the heat exchanger can be judged by detecting the temperature of the refrigerant in the water side heat exchanger, and then the opening degree of the electronic expansion valve and the working frequency of the compressor are adjusted to ensure that the heat exchange of the water side heat exchanger is sufficient, and the condensing pressure in the water side heat exchanger is controlled to improve the operating efficiency of the unit.

[0128] The embodiment of the present application also provides a computer readable storage medium, and the computer program is stored on the computer readable storage medium, and the computer program is executed by a processor to realize the steps of the control method of the heat pump water heater provided by any one of the preceding method embodiments.

[0129] The apparatus embodiments described above are only illustrative, and units described as separate components can or can not be physically separate, and components shown as units can or can not be physical units, i.e., can be located in one place, or can be distributed to multiple network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment.

[0130] Through the above description of the embodiments, those skilled in the art can clearly understand that the embodiments can be implemented by means of software plus a general hardware platform, and of course can also be implemented by hardware. Based on such understanding, the above technical solutions can be embodied in the form of a software product, and the computer software product can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods described in the embodiments or some parts of the embodiments.

[0131] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has", "having" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order in which they are described, unless explicitly stated otherwise. It is also to be understood that additional or alternative steps can be employed.

[0132] The above description is merely illustrative of the application and should not be taken as limiting the application. Numerous modifications and adaptations will occur to those skilled in the art without departing from the spirit and scope of the application, and each of the specific examples shown is presented only as an example. The scope of the application should be determined by the claims as set forth below and their legal equivalents rather than by the examples given. 。

Claims

1. A control method for a heat pump water heater unit, characterized in that, This invention relates to a heat pump water heater unit, comprising an inlet pipe, an outlet pipe, a refrigerant pipe, a water-side heat exchanger, an air-side heat exchanger, a compressor, a gas-liquid separator, an electronic expansion valve, a four-way valve, multiple temperature sensors, and a controller. The first end of the water-side heat exchanger is connected to both the inlet pipe and the first end of the refrigerant pipe, and the second end of the water-side heat exchanger is connected to both the outlet pipe and the second end of the refrigerant pipe. The first end of the electronic expansion valve is connected to the first end of the water-side heat exchanger via the refrigerant pipe, and the second end of the electronic expansion valve is connected to the first end of the air-side heat exchanger via the refrigerant pipe. The second end of the air-side heat exchanger is connected to the outlet pipe via the refrigerant pipe. The four-way valve is connected at its E end; its S end is connected to the first end of the gas-liquid separator via the refrigerant pipe; the second end of the gas-liquid separator is connected to the first end of the compressor via the refrigerant pipe; the second end of the compressor is connected to the D end of the four-way valve via the refrigerant pipe; and the C end of the four-way valve is connected to the second end of the water-side heat exchanger via the refrigerant pipe. Multiple temperature sensors are respectively located on the refrigerant pipe near the second end of the compressor, at the first end of the refrigerant pipe, on the inlet pipe, on the outlet pipe, and on the water-side heat exchanger. The multiple temperature sensors, the compressor, and the electronic expansion valve are electrically connected to the controller. The method includes: The controller acquires the temperature values ​​collected by the multiple temperature sensors respectively; The operating frequency of the compressor and / or the opening degree of the electronic expansion valve are controlled based on the temperature value. The plurality of temperature sensors includes a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor, a fifth temperature sensor, and a sixth temperature sensor; wherein the first temperature sensor is used to detect the initial temperature of the tubes of the water-side heat exchanger, the second temperature sensor is used to detect the temperature inside the tubes of the water-side heat exchanger, the third temperature sensor is used to detect the exhaust temperature of the compressor, the fourth temperature sensor is used to detect the outlet temperature of the water-side heat exchanger, the fifth temperature sensor is used to detect the inlet temperature of the inlet pipe, and the sixth temperature sensor is used to detect the outlet temperature of the outlet pipe. The step of controlling the operating frequency of the compressor and / or the opening degree of the electronic expansion valve based on the temperature value includes: Determine whether the outlet pipe temperature is less than or equal to the sum of the inlet water temperature and the first temperature threshold; If the outlet pipe temperature is determined to be less than or equal to the sum of the inlet water temperature and the first temperature threshold, the operating frequency of the compressor and / or the opening degree of the electronic expansion valve are controlled according to the initial pipe temperature, the outlet water temperature, the exhaust temperature and the pipe temperature. If the outlet pipe temperature is determined to be greater than the sum of the inlet water temperature and the first temperature threshold, the operating frequency of the compressor and / or the opening degree of the electronic expansion valve are controlled according to the pipe temperature and the outlet water temperature.

2. The method according to claim 1, characterized in that, When the outlet pipe temperature is determined to be less than or equal to the sum of the inlet water temperature and the first temperature threshold, the method of controlling the operating frequency of the compressor and / or the opening degree of the electronic expansion valve based on the initial pipe temperature, the outlet water temperature, the exhaust temperature, and the pipe temperature includes: If it is determined that the outlet temperature is less than or equal to the sum of the inlet water temperature and the first temperature threshold, it is further determined whether the initial pipe temperature is less than or equal to the sum of the outlet water temperature and the second temperature threshold, and whether the difference between the exhaust temperature and the outlet water temperature is greater than the third temperature threshold and less than the fourth temperature threshold. If it is determined that the initial pipe temperature is less than or equal to the sum of the outlet water temperature and the second temperature threshold, and the difference between the exhaust temperature and the outlet water temperature is less than or equal to the third temperature threshold, the opening of the electronic expansion valve is reduced, and the operating frequency of the compressor is reduced. If it is determined that the initial pipe temperature is less than or equal to the sum of the outlet water temperature and the second temperature threshold, and the difference between the exhaust temperature and the outlet water temperature is greater than or equal to the fourth temperature threshold, the operating frequency of the compressor is increased. If it is determined that the initial pipe temperature is less than or equal to the sum of the outlet water temperature and the second temperature threshold, and the difference between the exhaust temperature and the outlet water temperature is greater than the third temperature threshold and less than the fourth temperature threshold, the operating frequency of the compressor is increased. If the initial temperature of the pipe is determined to be greater than the sum of the outlet water temperature and the second temperature threshold, the operating frequency of the compressor is controlled according to the temperature in the pipe and the outlet water temperature.

3. The method according to claim 2, characterized in that, When it is determined that the initial temperature of the pipe is greater than the sum of the outlet water temperature and the second temperature threshold, the operating frequency of the compressor is controlled based on the temperature in the pipe and the outlet water temperature, including: If it is determined that the initial temperature of the pipe is greater than the sum of the outlet water temperature and the second temperature threshold, it is further determined whether the temperature in the pipe is greater than or equal to the sum of the outlet water temperature and the fifth temperature threshold, and less than or equal to the sum of the outlet water temperature and the sixth temperature threshold. If it is determined that the temperature in the pipe is less than the sum of the outlet water temperature and the fifth temperature threshold, the operating frequency of the compressor is increased; If the temperature in the pipe is determined to be greater than or equal to the sum of the outlet water temperature and the fifth temperature threshold, and less than or equal to the sum of the outlet water temperature and the sixth temperature threshold, the operating frequency of the compressor shall be maintained unchanged. If it is determined that the temperature in the pipe is greater than the sum of the outlet water temperature and the sixth temperature threshold, the operating frequency of the compressor is reduced.

4. The method according to claim 1, characterized in that, When it is determined that the outlet pipe temperature is greater than the sum of the inlet water temperature and the first temperature threshold, the step of controlling the operating frequency of the compressor and / or the opening degree of the electronic expansion valve based on the pipe temperature and the outlet water temperature includes: If it is determined that the outlet temperature is greater than the sum of the inlet water temperature and the first temperature threshold, it is further determined whether the temperature in the pipe is greater than the sum of the outlet water temperature and the seventh temperature threshold. If it is determined that the temperature in the pipe is greater than the sum of the outlet water temperature and the seventh temperature threshold, the operating frequency of the compressor is reduced; If it is determined that the temperature in the pipe is less than or equal to the sum of the outlet water temperature and the seventh temperature threshold, the opening of the electronic expansion valve is reduced.

5. The method according to claim 1, characterized in that, The first temperature sensor is disposed on the water-side heat exchanger at a first distance from the second end of the water-side heat exchanger, and the second temperature sensor is disposed on the water-side heat exchanger at a second distance from the second end of the water-side heat exchanger. Wherein, the first distance is the distance corresponding to one-fifth to one-quarter of the total length of the water-side heat exchanger, and the second distance is the distance corresponding to one-third to one-half of the total length of the water-side heat exchanger.

6. The method according to claim 1, characterized in that, The plurality of temperature sensors also includes a seventh temperature sensor and an eighth temperature sensor; The seventh temperature sensor and the eighth temperature sensor are both mounted on the air-side heat exchanger, and the seventh temperature sensor and the eighth temperature sensor are electrically connected to the controller.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the control method for the heat pump water heater unit according to any one of claims 1-6.

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