CN114183920B

CN114183920B - Temperature control method, device and equipment

Info

Publication number: CN114183920B
Application number: CN202111276081.4A
Authority: CN
Inventors: 李鹏; 赵润鹏; 孙强; 贾贾; 黄均吉; 范新胜; 李林锋; 陈志民
Original assignee: Zhengzhou Haier New Energy Technology Co ltd; Haier Smart Home Co Ltd; Qingdao Economic and Technological Development Zone Haier Water Heater Co Ltd
Current assignee: Zhengzhou Haier New Energy Technology Co ltd; Haier Smart Home Co Ltd; Qingdao Economic and Technological Development Zone Haier Water Heater Co Ltd
Priority date: 2021-10-29
Filing date: 2021-10-29
Publication date: 2023-08-18
Anticipated expiration: 2041-10-29
Also published as: CN114183920A

Abstract

The application belongs to the technical field of household appliances, and particularly relates to a temperature control method, a temperature control device and temperature control equipment. The application aims to solve the problem that the water temperature in the existing bathtub is continuously reduced in the bathing process. According to the temperature control method, the device and the equipment provided by the embodiment of the application, when the heat pump water heater is in the bathtub heat preservation mode, the refrigerant temperature of the heat exchanger on the outer wall surface of the bathtub and the water temperature in the bathtub are obtained, when the water temperature in the bathtub is smaller than the first target water temperature of the bathtub and the difference value between the water temperature in the bathtub and the first target water temperature is larger than or equal to a first preset value, the first target opening degree of the first electronic expansion valve is determined according to the refrigerant temperature, the water temperature in the bathtub, the refrigerant saturation temperature of the heat exchanger and the first target water temperature, and the first electronic expansion valve is controlled to be opened to the first target opening degree, so that the difference value between the water temperature in the bathtub and the first target water temperature is smaller than the first preset value, namely, the water temperature in the bathtub is kept within the preset range, and the heat preservation function of the bathtub is realized.

Description

Temperature control method, device and equipment

Technical Field

The present application relates to the field of household appliances, and in particular, to a method, an apparatus, and a device for controlling temperature.

Background

With the increasing emphasis of life quality, the bathtub is used as bathroom equipment, so that people can relieve fatigue, relax nerves and relax mind and body, and the warm and comfortable feeling of family life is improved, and the bathtub is more popular.

In the related art, the bathtub has no heat preservation function, and the water temperature in the bathtub is continuously reduced in the bathing process.

Disclosure of Invention

The embodiment of the application provides a temperature control method, a temperature control device and temperature control equipment, which are used for solving the technical problem that the bathtub has no heat preservation function in the prior art, and the temperature of water in the bathtub is continuously reduced in the bathing process.

In a first aspect, an embodiment of the present application provides a temperature control method, where a heat pump water heater includes an evaporator, a condenser, a heat exchanger, and a first electronic expansion valve, where the heat exchanger is disposed on a refrigerant path between the evaporator and the condenser and is mounted on an outer wall surface of a bathtub, and the first electronic expansion valve is mounted on the refrigerant path between the heat exchanger and the condenser;

the method comprises the following steps: when the heat pump water heater is in a bathtub heat preservation mode, acquiring the refrigerant temperature of the heat exchanger and the water temperature in the bathtub;

if the water temperature in the bathtub is smaller than a first target water temperature of the bathtub and the difference value between the water temperature in the bathtub and the first target water temperature is larger than or equal to a first preset value, determining a first target opening of the first electronic expansion valve according to the refrigerant temperature, the water temperature in the bathtub, the refrigerant saturation temperature of the heat exchanger and the first target water temperature; the first target opening enables the difference value between the water temperature in the bathtub and the first target water temperature to be smaller than the first preset value;

And controlling the first electronic expansion valve to be opened to a first target opening degree.

In one possible implementation manner, the determining the first target opening degree of the first electronic expansion valve according to the refrigerant temperature, the water temperature in the bathtub, the refrigerant saturation temperature of the heat exchanger and the first target water temperature includes:

determining a first opening degree variation of the first electronic expansion valve according to the refrigerant temperature and the refrigerant saturation temperature;

and determining the first target opening according to the current opening of the first electronic expansion valve and the first opening variation.

In one possible implementation manner, the determining the first opening degree variation of the first electronic expansion valve according to the refrigerant temperature and the refrigerant saturation temperature includes:

determining the current superheat degree of the heat exchanger according to the refrigerant temperature and the refrigerant saturation temperature;

and determining the first opening degree variation according to the current superheat degree of the heat exchanger and the target superheat degree of the heat exchanger.

In one possible implementation manner, the determining the first opening degree variation according to the current superheat degree of the heat exchanger and the target superheat degree of the heat exchanger includes: and determining the first opening variation according to the current superheat degree of the heat exchanger, the target superheat degree of the heat exchanger and the mapping relation among the superheat degree, the target superheat degree and the opening variation.

In one possible embodiment, the first target water temperature is greater than or equal to a preset temperature; the method further comprises the steps of:

when the first electronic expansion valve is controlled to keep the first target opening for a preset time period, the first target water temperature is adjusted to a second target water temperature, and the second target water temperature is smaller than the preset temperature;

determining the first target opening of the first electronic expansion valve according to the refrigerant temperature, the water temperature in the bathtub, the refrigerant saturation temperature and the second target water temperature, wherein the first target opening enables the difference value between the water temperature in the bathtub and the second target water temperature to be smaller than the first preset value.

In one possible embodiment, the heat pump water heater further comprises: the external surface of the water tank is in contact with the condenser, the second electronic expansion valve is arranged on a refrigerant passage between the heat exchanger and the evaporator, and the compressor is arranged on the refrigerant passage between the evaporator and the condenser;

the method further comprises the steps of: when the heat pump water heater is in a water tank heating mode, acquiring a first suction superheat degree of the compressor;

Determining a second target opening of the first electronic expansion valve according to the first suction superheat degree of the compressor and the target superheat degree of the compressor; the second target opening enables the difference value between the water temperature in the water tank and the second target water temperature of the water tank to be smaller than a second preset value;

controlling the first electronic expansion valve to be opened to the second target opening degree; and controlling the second electronic expansion valve to be opened to a preset opening degree.

In one possible embodiment, the method further comprises:

when the heat pump water heater is in the bathtub heat preservation mode, obtaining a second suction superheat degree of the compressor;

determining a third target opening degree of the second electronic expansion valve according to the second suction superheat degree of the compressor and the target superheat degree of the compressor; the third target opening enables the difference value between the water temperature in the bathtub and the first target water temperature to be smaller than the first preset value;

and controlling the second electronic expansion valve to be opened to the third target opening degree.

In one possible embodiment, the method further comprises:

responding to an operation instruction, and controlling the heat pump water heater to enter a bathtub heat preservation mode; alternatively, the heat pump water heater further includes: the water level detection device is arranged in the bathtub, and the human body detection device is arranged on the outer wall surface of the bathtub;

Acquiring the water level in the bathtub acquired by the water level detection device, and acquiring the duration of a target object in the preset range of the bathtub by the human body detection device;

when the water level in the bathtub is greater than or equal to a preset water level, and the human body detection device collects that the duration time of the target object in the preset range of the bathtub is longer than the preset time, the heat pump water heater is controlled to enter a bathtub heat preservation mode.

In a second aspect, embodiments of the present application provide a temperature control device that may be provided in a heat pump water heater. The heat pump water heater includes: the heat exchanger is arranged on a refrigerant passage between the evaporator and the condenser and is arranged on the outer wall surface of the bathtub, and the first electronic expansion valve is arranged on the refrigerant passage between the heat exchanger and the condenser.

The temperature control device may include an acquisition module, a determination module, and a control module, wherein:

the acquisition module is used for acquiring the refrigerant temperature of the heat exchanger and the water temperature in the bathtub when the heat pump water heater is in a bathtub heat preservation mode.

The determining module is configured to determine, if the water temperature in the bathtub is less than a first target water temperature of the bathtub and a difference value between the water temperature in the bathtub and the first target water temperature is greater than or equal to a first preset value, a first target opening of the first electronic expansion valve according to the refrigerant temperature, the water temperature in the bathtub, the refrigerant saturation temperature of the heat exchanger, and the first target water temperature; the first target opening enables the difference value between the water temperature in the bathtub and the first target water temperature to be smaller than the first preset value.

The control module is used for controlling the first electronic expansion valve to be opened to a first target opening degree.

In one possible implementation manner, the determining module is specifically configured to determine a first opening variation of the first electronic expansion valve according to the refrigerant temperature and the refrigerant saturation temperature;

In one possible implementation manner, the determining module is specifically configured to determine a current superheat degree of the heat exchanger according to the refrigerant temperature and the refrigerant saturation temperature;

In one possible implementation manner, the determining module is specifically configured to determine the first opening variation according to a mapping relationship among a current superheat degree of the heat exchanger, a target superheat degree of the heat exchanger, and a superheat degree, a target superheat degree, and an opening variation.

In one possible implementation manner, the first target water temperature is greater than or equal to a preset temperature, and the temperature control device further includes an adjustment module, where the adjustment module is configured to adjust the first target water temperature to a second target water temperature when the first electronic expansion valve is controlled to keep the first target opening for a preset duration, and the second target water temperature is less than the preset temperature;

the determining module is further configured to determine the first target opening of the first electronic expansion valve according to the coolant temperature, the water temperature in the bathtub, the coolant saturation temperature, and the second target water temperature, where the first target opening makes a difference between the water temperature in the bathtub and the second target water temperature smaller than the first preset value.

In one possible implementation, the heat pump water heater further comprises: the external surface of the water tank is in contact with the condenser, the second electronic expansion valve is arranged on a refrigerant passage between the heat exchanger and the evaporator, and the compressor is arranged on the refrigerant passage between the evaporator and the condenser;

the acquisition module is also used for acquiring a first suction superheat degree of the compressor when the heat pump water heater is in a water tank heating mode;

the determining module is further configured to determine a second target opening of the first electronic expansion valve according to a first suction superheat degree of the compressor and a target superheat degree of the compressor; the second target opening enables the difference value between the water temperature in the water tank and the second target water temperature of the water tank to be smaller than a second preset value;

the control module is also used for controlling the first electronic expansion valve to be opened to the second target opening degree; and controlling the second electronic expansion valve to be opened to a preset opening degree.

In one possible implementation, the obtaining module is further configured to obtain a second suction superheat of the compressor when the heat pump water heater is in the bathtub insulation mode;

The determining module is further configured to determine a third target opening of the second electronic expansion valve according to a second suction superheat degree of the compressor and a target superheat degree of the compressor; the third target opening enables the difference value between the water temperature in the bathtub and the first target water temperature to be smaller than the first preset value;

the control module is also used for controlling the second electronic expansion valve to be opened to the third target opening degree.

In one possible implementation, the control module is further configured to control the heat pump water heater to enter a bathtub keep warm mode in response to an operation instruction.

In one possible implementation, the heat pump water heater further comprises: the water level detection device is arranged in the bathtub, and the human body detection device is arranged on the outer wall surface of the bathtub;

the acquisition module is also used for acquiring the water level in the bathtub, which is acquired by the water level detection device, and acquiring the duration time of the target object in the preset range of the bathtub by the human body detection device;

the control module is further used for controlling the heat pump water heater to enter a bathtub heat preservation mode when the water level in the bathtub is greater than or equal to a preset water level, and the human body detection device collects that the duration time of the target object in the preset range of the bathtub is longer than the preset duration time.

In a third aspect, an embodiment of the present application provides a temperature control apparatus, including: a processor, a memory;

the memory stores a computer program;

the processor executes the computer program stored in the memory to implement the temperature control method according to any one of the first aspects.

In a fourth aspect, an embodiment of the present application further provides a heat pump water heater, which includes the temperature control device according to the third aspect.

In a fifth aspect, an embodiment of the present application further provides a bathroom facility, which includes a heat pump water heater, a temperature control device according to the third aspect, and a bathtub.

In a sixth aspect, an embodiment of the present application further provides a computer readable storage medium, where computer executable instructions are stored, where the computer executable instructions are executed by a processor to implement the temperature control method according to the first aspect.

In a seventh aspect, embodiments of the present application also provide a computer program product comprising a computer program which, when executed by a processor, implements the temperature control method according to any of the first aspects.

The embodiment of the application provides a temperature control method, a device and equipment, wherein a heat pump water heater comprises a heat pump water heater, and the heat pump water heater comprises the following components: the heat exchanger is arranged on a refrigerant passage between the evaporator and the condenser and is arranged on the outer wall surface of the bathtub, and the first electronic expansion valve is arranged on the refrigerant passage between the heat exchanger and the condenser. According to the temperature control method provided by the embodiment of the application, when the heat pump water heater is in the bathtub heat preservation mode, the refrigerant temperature of the heat exchanger on the outer wall surface of the bathtub and the water temperature in the bathtub are obtained, when the water temperature in the bathtub is smaller than the first target water temperature of the bathtub and the difference value between the water temperature in the bathtub and the first target water temperature is larger than or equal to the first preset value, the first target opening degree of the first electronic expansion valve is determined according to the refrigerant temperature, the water temperature in the bathtub, the refrigerant saturation temperature of the heat exchanger and the first target water temperature, and the first electronic expansion valve is controlled to be opened to the first target opening degree, so that the difference value between the water temperature in the bathtub and the first target water temperature is smaller than the first preset value, namely the water temperature in the bathtub is kept within the preset range, the heat preservation function of the bathtub is realized, and the water temperature in the bathtub is prevented from being reduced along with the extension of bath time. In addition, the embodiment of the application is combined with the heat pump water heater to control the temperature, the refrigerant of the heat pump water heater is utilized to exchange heat, a heating device is not required to be additionally arranged, the heat pump water heater is linked with the bathtub, and the operation is flexible.

Drawings

Fig. 1 is a schematic view of an application scenario provided in an embodiment of the present application;

fig. 2 is a schematic structural diagram of a heat pump water heater according to an embodiment of the present application;

FIG. 3 is a schematic flow chart of a temperature control method according to an embodiment of the present application;

FIG. 4 is a schematic flow chart of another temperature control method according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of a temperature control device according to an embodiment of the present application;

fig. 6 is a schematic hardware structure of a temperature control device according to an embodiment of the present application.

Detailed Description

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the application. Rather, they are merely examples of apparatus and methods consistent with aspects of the application as detailed in the accompanying claims.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The bathtub, which is used as bathroom equipment, can relieve fatigue, relax nerves and relax mind and body, and is becoming popular. The bathtub in the prior art has no heat preservation function, and the water temperature in the bathtub is gradually reduced in the bathing process, so that the bathing experience is affected.

Typically, to increase the temperature of the water in the bath, the user continues to add hot water to the bath. Not only is inconvenient to operate, but also because more water is already in the bathtub, a large amount of hot water is required to be heated to improve the overall water temperature of the water in the bathtub, and the practicability is poor.

In the related art, in order to maintain the water temperature in the bathtub, some bathtubs are provided with an electric heating device to heat the water in the tub. The mode has the advantages of leakage risk, poor safety and high electric energy consumption.

The inventor researches and discovers that the electric heating device arranged in the bathtub is used for heating and preserving the heat of water in the bathtub, and the principle is the same as that of an electric water heater. This approach consumes a lot of power, resulting in an increase in the use cost for the user.

The inventor continues to intensively study, and the bathtub and the water heater are both bath equipment, the water heater can prepare hot water and can keep the temperature, and the inventor thinks of keeping the temperature of water in the bathtub by referring to the heating and heat-preserving principle of the water heater.

Water heaters are generally classified into electric water heaters, gas water heaters, solar water heaters, and air-source heat pump water heaters according to the difference of water heating principles. The inventors analyzed the feasibility of various water heater and bathtub combinations. The gas water heater heats water by heat generated by gas combustion, and has complex structure and pipeline arrangement and low combination feasibility. Although the solar water heater is energy-saving and environment-friendly, the combination feasibility of the bathtub positioned indoors and the heat collecting pipe of the solar water heater is low. The air energy heat pump water heater transfers heat in air into water by using the inverse Carnot principle, comprises a refrigerant pipeline and a water pipeline, and has high feasibility of combining with a bathtub, wherein part of the air energy heat pump water heater is positioned indoors and the other part of the air energy heat pump water heater is positioned outdoors.

The inventors have further studied how to combine a heat pump water heater with a bathtub to maintain the temperature of water in the bathtub and to keep the bathtub at a constant temperature. The principle of heating water of the heat pump water heater is that the water tank exchanges heat with the refrigerant in the condenser outside the water tank, so that hot water is produced.

In view of the above, the inventor sets a heat exchanger on the outer side of the bathtub, the heat exchanger is communicated to a refrigerant passage of the heat pump water heater, and the refrigerant in the heat exchanger exchanges heat with the bathtub to heat water in the bathtub, so that the bathtub is in a constant temperature state.

Further, the inventor sets up first electronic expansion valve on the refrigerant passageway between heat exchanger and condenser, sets up the second electronic expansion valve on the refrigerant passageway between heat exchanger and the evaporimeter, through adjusting first electronic expansion valve and second electronic expansion valve for the refrigerant can be under different mode, heats the water in the water tank, heats the water in the bathtub.

Compared with the arrangement of an electric heating device on the bathtub, the temperature control method, the device and the equipment can not only keep the water temperature in the bathtub, but also have low energy consumption; is linked with the water heater, and is beneficial to improving the operability.

Next, an application scenario of an embodiment of the present application will be described with reference to fig. 1.

Fig. 1 is a schematic diagram of an application scenario provided in an embodiment of the present application. Referring to fig. 1, the method includes: the heat exchanger 104 is mounted on the outer wall surface of the bathtub 105, and the refrigerant passage 102 is arranged between the heat exchanger 104 and the evaporator of the outdoor unit 103, between the evaporator of the outdoor unit 103 and the condenser outside the water tank 101, and between the condenser outside the water tank 101 and the heat exchanger 104. The evaporator of the outdoor unit 103 exchanges heat with the outdoor air, so that the refrigerant in the evaporator evaporates to form high-temperature gas; the high-temperature refrigerant can enter the heat exchanger 104 to be condensed and exchange heat with the water in the bathtub 105, so that the water in the bathtub 105 is kept at the target water temperature; the high temperature refrigerant may enter the condenser outside the water tank 101 to exchange heat with the water in the water tank 101, thereby heating the water in the water tank 101. According to the application, the water in the bathtub 105 is heated while the water in the water tank 101 is heated, so that the water in the bathtub 105 is kept at the target water temperature, and the bathing experience is improved.

The technical scheme shown in the application is described in detail by specific examples. It should be noted that the following embodiments may exist alone or in combination with each other, and for the same or similar content, the description will not be repeated in different embodiments.

Fig. 2 is a schematic structural diagram of a heat pump water heater according to an embodiment of the present application; fig. 3 is a schematic flow chart of a temperature control method according to an embodiment of the present application.

Referring to fig. 2 and 3, a temperature control method according to an embodiment of the present application may include:

s201, when the heat pump water heater is in a bathtub heat preservation mode, acquiring the refrigerant temperature of the heat exchanger and the water temperature in the bathtub.

The execution main body of the embodiment of the application can be a heat pump water heater or a control device arranged in the heat pump water heater. Alternatively, the control device of the heat pump water heater can be implemented by software, or can be implemented by a combination of software and hardware.

Referring to fig. 2, the heat pump water heater according to the embodiment of the present application includes an evaporator 208, a condenser 211, a heat exchanger 205, and a first electronic expansion valve 201, wherein the heat exchanger 205 is disposed on a refrigerant path between the evaporator 208 and the condenser 211 and is mounted on an outer wall surface of the bathtub 202, and the first electronic expansion valve 201 is mounted on the refrigerant path between the heat exchanger 205 and the condenser 211, and adjusts a flow rate and a pressure of a refrigerant entering the heat exchanger 205 by controlling an opening degree of the first electronic expansion valve 201.

The heat exchanger 205 may be a micro-channel heat exchanger, and the micro-channel is a flat tube, so that the heat exchange area with the bathtub is increased, and the heat exchange efficiency is improved. Optionally, the heat exchangers 205 are uniformly arranged on the outer wall surface of the bathtub 202, so that water in the bathtub can be heated uniformly, and large water temperature differences in different areas in the bathtub are avoided.

The evaporator 208 is installed outdoors, and evaporates a refrigerant inside thereof into a gas in order to exchange heat with air. In order to increase the heat exchange efficiency, a fan is installed on the heat exchange surface of the evaporator 208 to accelerate the flow of air. The fan can be a variable frequency fan or a multi-gear fan. Optionally, the rotating speed of the fan is controlled according to the outdoor environment temperature and the suction temperature of the compressor, so that the efficiency and the system performance of the heat pump system are improved.

A compressor 209 is further installed in the refrigerant passage between the evaporator 208 and the condenser 211, and the compressor 209 is configured to pressurize the high-temperature gas refrigerant of the evaporator 208 to form a high-temperature high-pressure refrigerant.

The condenser 211 is installed at the outside of the water tank 210, the outer surface of the water tank 210 is in contact with the condenser 211, and the high temperature refrigerant in the condenser 211 exchanges heat with the water in the water tank 210 through the sidewall of the water tank 210, thereby heating the water in the water tank 210.

In this step, the heat pump water heater is operated in a bathtub thermal mode, that is, the bathtub is in use. The temperature of the refrigerant of the heat exchanger 205 is obtained, for example, a temperature sensing device is disposed in a pipe of the heat exchanger 205, and the temperature of the refrigerant of the bathtub is obtained through the temperature sensing device. The water temperature in the bathtub 202 is obtained, and the water temperature in the bathtub 202 can be detected by installing a temperature sensor 203 on the bathtub 202.

S202, if the water temperature in the bathtub is smaller than a first target water temperature of the bathtub and the difference value between the water temperature in the bathtub and the first target water temperature is larger than or equal to a first preset value, determining a first target opening of the first electronic expansion valve according to the refrigerant temperature, the water temperature in the bathtub, the refrigerant saturation temperature of the heat exchanger and the first target water temperature.

The first target water temperature may be preset, and the first target water temperatures set by different users may be different. Typically, the first target water temperature is between 35 ℃ and 43 ℃ avoiding too low or too high a water temperature.

It is necessary to determine the relationship between the water temperature in the bath tub and the first target water temperature, and when the water temperature in the bath tub 202 is smaller than the first target water temperature of the bath tub and the difference between the water temperature in the bath tub and the first target water temperature is greater than or equal to a first preset value, the water temperature in the bath tub is adjusted by controlling the opening of the first electronic expansion valve 201. Otherwise, no adjustment is made.

Illustratively, the user sets the first target water temperature to 38 degrees Celsius and the first preset value to 1 degree Celsius. When the obtained water temperature in the bathtub is 37.5 ℃, the temperature of the water in the bathtub is 37.5 ℃ less than 38 ℃, the difference between the temperature of the water in the bathtub and the temperature of the water in the bathtub is 37.5 ℃ less than 38 ℃ and the temperature of the water in the bathtub is 0.5 ℃ less than 1 ℃, which indicates that the water temperature in the bathtub is within a set range, and the water temperature in the bathtub does not need to be adjusted. When the obtained water temperature in the bathtub is 36 ℃, the temperature of the water in the bathtub is less than 38 ℃, the difference between the temperature of the water in the bathtub and the temperature of the water in the bathtub is 2 ℃, and the temperature of the water in the bathtub is greater than 1 ℃ when the temperature of the water in the bathtub is 36 ℃, which means that the water temperature in the bathtub is lower than a preset temperature range, and the water temperature in the bathtub needs to be adjusted.

In this step, the first target opening degree of the first electronic expansion valve 201 is determined based on the refrigerant temperature of the heat exchanger, the water temperature in the bathtub, the refrigerant saturation temperature of the heat exchanger, and the first target water temperature. At the first target opening, the difference between the water temperature in the bathtub 202 and the first target water temperature can be made smaller than a first preset value.

The refrigerant saturation temperature of the heat exchanger is the temperature of the liquid and the vapor in a dynamic balance state, namely, in a saturation state. The refrigerant saturation temperature of the heat exchanger is related to the pressure, and the refrigerant saturation temperature is determined in a corresponding table of the pressure and the refrigerant saturation temperature by acquiring the pressure of the refrigerant in the heat exchanger.

And S203, controlling the first electronic expansion valve to be opened to a first target opening degree.

The first electronic expansion valve 201 is an electromagnetic electronic expansion valve, and the position of the needle valve is controlled by controlling the voltage applied to the solenoid, so that the first electronic expansion valve 201 is controlled to be opened to a first target opening degree. Alternatively, the first electronic expansion valve 201 is an electric electronic expansion valve, and the position of the needle valve is controlled by controlling the stepping motor, so that the first electronic expansion valve 201 is controlled to be opened to a first target opening degree.

Here, the first electronic expansion valve 201 is controlled to be opened to the first target opening degree, not to say, the first electronic expansion valve 201 is controlled from zero opening to the first target opening degree. In general, the first electronic expansion valve 201 is adjusted to an initial opening degree according to a set program after the heat pump system is powered on, or to a first target opening degree according to the current number of steps of the first electronic expansion valve 201 in an automatic control stage.

In some implementations, the first target water temperature of the bathtub is unchanged; in other implementations, the first target water temperature of the bathtub is variable.

Optionally, when the first target water temperature is less than the preset temperature, the first target water temperature is unchanged. Illustratively, the preset temperature is 40 ℃, the first target water temperature is 38 ℃, which is less than the preset temperature, and the first target water temperature is unchanged in the bathtub insulation mode.

Optionally, the first target water temperature is greater than or equal to a preset temperature, and the temperature control method of the embodiment of the application further includes:

step 1: and when the first electronic expansion valve is controlled to keep the first target opening for a preset time period, the first target water temperature is adjusted to a second target water temperature, and the second target water temperature is smaller than the preset temperature. For example, the first target water temperature is 42 ℃, and the bath is performed at the water temperature for a long time, so that problems such as dizziness and fatigue can occur. And when the first electronic expansion valve is controlled to keep the first target opening degree for a preset time period, that is to say, the first target water temperature is kept for a preset time period, for example, the preset time period is 10 minutes, the first target water temperature is adjusted to be a second target water temperature, and the second target water temperature is smaller than the preset temperature, for example, the second target water temperature is 39 ℃.

Step 2: determining the first target opening of the first electronic expansion valve according to the refrigerant temperature, the water temperature in the bathtub, the refrigerant saturation temperature and the second target water temperature, wherein the first target opening enables the difference value between the water temperature in the bathtub and the second target water temperature to be smaller than the first preset value. Note that, the execution process may refer to the execution process of S302, and will not be described herein.

According to the embodiment of the application, the first target water temperature of the bathtub is changed, so that a user is prevented from bathing at a higher temperature for a long time, and the bathing safety is improved.

Therefore, in the temperature control method provided by the embodiment of the application, when the heat pump water heater is in the bathtub heat preservation mode, the refrigerant temperature of the heat exchanger on the outer wall surface of the bathtub and the water temperature in the bathtub are obtained, when the water temperature in the bathtub is smaller than the first target water temperature of the bathtub and the difference value between the water temperature in the bathtub and the first target water temperature is larger than or equal to a first preset value, the first target opening degree of the first electronic expansion valve is determined according to the refrigerant temperature, the water temperature in the bathtub, the refrigerant saturation temperature of the heat exchanger and the first target water temperature, and the first electronic expansion valve is controlled to be opened to the first target opening degree, so that the difference value between the water temperature in the bathtub and the first target water temperature is smaller than the first preset value, namely, the water temperature in the bathtub is kept within the preset range, the heat preservation function of the bathtub is realized, and the water temperature in the bathtub is prevented from being reduced along with the extension of bath time.

In addition, the embodiment of the application is combined with the heat pump water heater to control the temperature, the refrigerant of the heat pump water heater is utilized to exchange heat, a heating device is not required to be additionally arranged, the heat pump water heater is linked with the bathtub, and the operation is flexible.

The above-described temperature control method will be described in detail with reference to fig. 4, based on the embodiment shown in fig. 3.

Fig. 4 is a schematic diagram of another temperature control method according to an embodiment of the present application. Referring to fig. 4, the method includes:

s401, acquiring a working mode of the heat pump water heater.

The operation mode of the heat pump water heater can be determined to be various through the operation instruction input by the user, for example, the user can enable the heat pump water heater to enter a water tank heating mode through the function keys of the operation panel; the working mode of the heat pump water heater can be determined according to the detected data, for example, when the temperature outside the evaporator is detected to be lower than the preset temperature, the problem of frosting of the evaporator is indicated, and the working mode of the heat pump water heater is determined to be a defrosting mode.

The following description is made with respect to a bathtub heat preservation mode of the heat pump water heater, in which the temperature of water in the bathtub is adjusted, and a water tank heating mode, in which the water in the water tank 210 is heated, for temperature control.

The water in the tank 210 needs to be heated prior to bathing with the tub 202. Optionally, the heat pump water heater can enter a water tank heating mode after being powered on. Or, in response to an operation instruction of a user, controlling the heat pump water heater to enter a water tank heating mode. The operation instruction may be a voice instruction or an instruction input through a function key.

In the embodiment of the application, the heat pump water heater can be controlled to enter a bathtub heat preservation mode in the following two modes. In one possible implementation, the heat pump water heater is controlled to enter a bathtub keep warm mode in response to a user operation instruction. In another possible implementation, the heat pump water heater may be controlled to enter a bathtub thermal mode by:

step 1: the water level in the bathtub acquired by the water level detection device is acquired, and the human body detection device acquires the duration of the target object existing in the preset range of the bathtub. Referring to fig. 2, the heat pump water heater according to the embodiment of the present application further includes a water level detection device 204 and a human body detection device 206, wherein the water level detection device 204 is installed in the bathtub 202 for detecting the water level in the bathtub 202; the human body detecting means 206 is installed on the outer wall surface of the bathtub 202, for example, on the top of the outer wall surface of the bathtub 202, for detecting whether a human body is present. The human body detection device 206 may be an infrared sensor, and the human body detection device 206 may also be an optoelectronic proximity sensor. The human detection device 206 collects the duration of the presence of the target object within the predetermined range of the bathtub 202, that is, the human detection device 206 is able to collect the presence of the target object within the predetermined range of the bathtub 220 and the duration of the presence of the target object.

Step 2: when the water level in the bathtub is greater than or equal to a preset water level, and the human body detection device collects that the duration time of the target object in the preset range of the bathtub is longer than the preset time, the heat pump water heater is controlled to enter a bathtub heat preservation mode. This indicates that bath tub 202 has a certain amount of bath water therein and that the target subject is staying in place for a certain period of time, indicating that the user is about to bath in tub 202.

When the heat pump water heater is in the bathtub heat preservation mode, the following steps S402 to S409 are executed; when the heat pump water heater is in the tank heating mode, the following steps S410 to S412 are performed.

S402, acquiring the temperature of the refrigerant of the heat exchanger and the water temperature in the bathtub.

It should be noted that the execution of step S402 may refer to the execution of step S301, and will not be described herein.

Next, the first opening variation of the first electronic expansion valve is determined according to the refrigerant temperature and the refrigerant saturation temperature, where step S403 and step S402 are a specific implementation manner. The premise of performing step S403 is identical to the step of performing step 302 in the above embodiment, that is, the water temperature in the bathtub is smaller than the first target water temperature of the bathtub, and the difference from the first target water temperature is greater than or equal to the first preset value, that is, the water temperature in the bathtub has not satisfied the set condition.

S403, determining the current superheat degree of the heat exchanger according to the refrigerant temperature and the refrigerant saturation temperature.

Optionally, the difference between the refrigerant temperature and the refrigerant saturation temperature is the current superheat degree of the heat exchanger. For another example, a mapping relationship exists between the difference value of the refrigerant temperature and the refrigerant saturation temperature and the superheat degree of the heat exchanger, and the current superheat degree of the heat exchanger is determined according to the current difference value of the refrigerant temperature and the refrigerant saturation temperature and the mapping relationship.

S404, determining the first opening degree variation according to the current superheat degree of the heat exchanger and the target superheat degree of the heat exchanger.

The first opening degree variation may be determined in various manners, for example, a difference between a current superheat degree of the heat exchanger and a target superheat degree of the heat exchanger has a corresponding relationship with the first opening degree variation, and the first opening degree variation is determined according to the difference. For another example, the first opening degree variation is determined according to the current superheat degree of the heat exchanger, the target superheat degree of the heat exchanger, and a mapping relationship among the superheat degree, the target superheat degree and the opening degree variation. The mapping relationship among the superheat degree, the target superheat degree and the opening degree variation can be a calculation formula or a corresponding table. The first opening degree variation amount may be determined from the map.

S405, determining the first target opening according to the current opening of the first electronic expansion valve and the first opening variation.

In the embodiment of the application, the sum of the current opening of the first electronic expansion valve and the first opening variation is determined as the first target opening. When the first opening degree variation is positive, the opening degree of the first electronic expansion valve is increased, and when the first opening degree variation is negative, the opening degree of the first electronic expansion valve is reduced, and of course, when the first opening degree variation is zero, the opening degree of the first electronic expansion valve is kept unchanged.

When the variable frequency compressor is adopted in the heat pump water heater, the opening of the first electronic expansion valve is required to be adjusted in each valve adjusting period, so that the system performance and stability of the heat pump water heater are improved.

S406, controlling the first electronic expansion valve to be opened to a first target opening degree.

It should be noted that the execution of step S406 may refer to the execution of step S303, and will not be described herein.

Step S407 to step S409 are performed when the heat pump water heater is in the bathtub heat preservation mode, and the second electronic expansion valve is controlled. Referring to fig. 2, a second electronic expansion valve 207 is installed in the refrigerant passage between the heat exchanger 205 and the evaporator 208, and the flow rate and pressure of the refrigerant flowing into the evaporator 208 are adjusted by controlling the opening degree of the second electronic expansion valve 207.

S407, obtaining a second suction superheat degree of the compressor.

In some implementations, the suction temperature and the discharge temperature of the compressor 209 are obtained, and the difference between the suction temperature and the discharge temperature of the compressor 209 is the second suction superheat. Or the difference between the suction temperature and the discharge temperature of the compressor is multiplied by a preset correction coefficient to obtain the second suction superheat degree of the compressor. The specific manner of obtaining the second suction superheat of the compressor 209 is not limited in the embodiment of the present application.

And S408, determining a third target opening degree of the second electronic expansion valve according to the second suction superheat degree of the compressor and the target superheat degree of the compressor.

The third target opening enables the difference value between the water temperature in the bathtub and the first target water temperature to be smaller than a first preset value, namely, the second electronic expansion valve is suitable for adjusting the first electronic expansion valve in the bathtub heat preservation mode. During the adjustment of the first electronic expansion valve, the refrigerant flow and the pressure in the whole refrigerant passage of the heat pump water heater can be influenced, and the second electronic expansion valve is adjusted adaptively.

In some embodiments, determining a third opening variation of the second electronic expansion valve based on the second suction superheat of the compressor and the target superheat of the compressor; and determining a third target opening degree of the second electronic expansion valve according to the current opening degree and the third opening degree variation of the second electronic expansion valve. And determining a third opening variation of the compressor according to the mapping relation, the second suction superheat of the compressor and the target superheat of the compressor.

S409, controlling the second electronic expansion valve to be opened to the third target opening degree.

The second electronic expansion valve may be the same as the first electronic expansion valve, and the execution of step S409 may refer to the execution of step S303, which is not described herein.

The control modes of the first electronic expansion valve and the second electronic expansion valve when the heat pump water heater is in the tank heating mode are described below.

S410, acquiring the first suction superheat degree of the compressor.

It should be noted that the execution of step S410 may refer to the execution of step S407, and will not be described herein.

S411, determining a second target opening degree of the first electronic expansion valve according to the first suction superheat degree of the compressor and the target superheat degree of the compressor.

It should be noted that the execution of step S411 may refer to the execution of step S408, and will not be described herein.

It should be further noted that, the difference between step S412 and step S408 is that, in step S408, according to the second suction superheat degree of the compressor and the target superheat degree of the compressor, the third target opening degree of the second electronic expansion valve is determined, and in step S412, according to the first suction superheat degree of the compressor and the target superheat degree of the compressor, the second target opening degree of the first electronic expansion valve is determined, where the second target opening degree makes the difference between the water temperature in the water tank and the second target water temperature of the water tank smaller than the second preset value, that is, the second target opening degree makes the water temperature in the water tank keep within the preset range.

S412, controlling the first electronic expansion valve to be opened to the second target opening degree; and controlling the second electronic expansion valve to be opened to a preset opening degree.

Wherein, the first electronic expansion valve is controlled to be opened to the second target opening degree, S303 may be referred to; controlling the second electronic expansion valve to be opened to a preset opening degree, S410 may be referred to; and will not be described in detail herein.

The preset opening degree of the second electronic expansion valve can be the maximum opening degree of the second electronic expansion valve, and at the moment, the heat exchanger plays a role of an evaporator, so that the system performance and the heating efficiency of the heat pump water heater are improved.

According to the temperature control method provided by the embodiment of the application, the water temperature of the bathtub in the bathtub heat preservation mode and the water temperature of the water tank in the water tank heating mode are respectively regulated through the first electronic expansion valve and the second electronic expansion valve, so that the bathtub is kept constant, and the functions of the heat pump water heater are expanded.

According to the heat pump water heater disclosed by the embodiment of the application, the heat exchanger is added on the outer wall surface of the bathtub, the heat exchanger is connected in series to the refrigerant passage between the condenser and the evaporator, and the first electronic expansion valve is arranged between the heat exchanger and the condenser to control the refrigerant flow and the pressure of the heat exchanger, so that the bathtub realizes a constant temperature function, and the functions and application scenes of the heat pump water heater are expanded.

According to the embodiment of the application, the first electronic expansion valve and the second electronic expansion valve are arranged, so that two-stage refrigerant throttling is realized, the constant temperature function of the water tank for preparing hot water and the bathtub is realized by using less air heat energy, the energy is saved, the environment is protected, and the use cost of a user is reduced.

Under the water tank heating mode, the second electronic expansion valve is opened to the maximum opening degree, and the heat exchanger is converted into an evaporator, so that the heat pump water heater becomes a double-evaporator system, and the efficiency of preparing hot water by the water tank can be improved. In addition, as the heat exchanger functioning as the evaporator is located indoors, the heat pump water heater can utilize the heat exchanger to assist in heat exchange in a defrosting mode, and the temperature of the outdoor evaporator is increased, so that defrosting is performed. The four-way reversing valve is not needed, and the structure and the control logic are simplified.

Fig. 5 is a schematic structural diagram of a temperature control device according to an embodiment of the present application. The temperature control device 500 may be provided in a heat pump water heater. The heat pump water heater includes: the heat exchanger is arranged on a refrigerant passage between the evaporator and the condenser and is arranged on the outer wall surface of the bathtub, and the first electronic expansion valve is arranged on the refrigerant passage between the heat exchanger and the condenser.

Referring to fig. 5, the temperature control apparatus 500 may include an acquisition module 501, a determination module 502, and a control module 503, where:

the obtaining module 501 is configured to obtain a refrigerant temperature of the heat exchanger and a water temperature in the bathtub when the heat pump water heater is in a bathtub thermal insulation mode.

The determining module 502 is configured to determine, if the water temperature in the bathtub is less than a first target water temperature of the bathtub and a difference value between the water temperature in the bathtub and the first target water temperature is greater than or equal to a first preset value, a first target opening of the first electronic expansion valve according to the refrigerant temperature, the water temperature in the bathtub, the refrigerant saturation temperature of the heat exchanger, and the first target water temperature; the first target opening enables the difference value between the water temperature in the bathtub and the first target water temperature to be smaller than the first preset value.

The control module 503 is configured to control the first electronic expansion valve to open to a first target opening degree.

In a possible implementation manner, the determining module 502 is specifically configured to determine a first opening variation of the first electronic expansion valve according to the refrigerant temperature and the refrigerant saturation temperature;

In a possible implementation manner, the determining module 502 is specifically configured to determine a current superheat degree of the heat exchanger according to the refrigerant temperature and the refrigerant saturation temperature;

In a possible implementation manner, the determining module 502 is specifically configured to determine the first opening variation according to a mapping relationship among a current superheat degree of the heat exchanger, a target superheat degree of the heat exchanger, and a superheat degree, a target superheat degree, and an opening variation.

In a possible implementation manner, the first target water temperature is greater than or equal to a preset temperature, and the temperature control device 500 further includes an adjustment module, where the adjustment module is configured to adjust the first target water temperature to a second target water temperature when the first electronic expansion valve is controlled to maintain the first target opening for a preset duration, where the second target water temperature is less than the preset temperature;

the determining module 502 is further configured to determine the first target opening of the first electronic expansion valve according to the coolant temperature, the water temperature in the bathtub, the coolant saturation temperature, and the second target water temperature, where the first target opening makes a difference between the water temperature in the bathtub and the second target water temperature smaller than the first preset value.

the obtaining module 501 is further configured to obtain a first suction superheat degree of the compressor when the heat pump water heater is in a water tank heating mode;

the determining module 502 is further configured to determine a second target opening of the first electronic expansion valve according to a first suction superheat degree of the compressor and a target superheat degree of the compressor; the second target opening enables the difference value between the water temperature in the water tank and the second target water temperature of the water tank to be smaller than a second preset value;

the control module 503 is further configured to control the first electronic expansion valve to open to the second target opening; and controlling the second electronic expansion valve to be opened to a preset opening degree.

In a possible implementation manner, the obtaining module 501 is further configured to obtain a second suction superheat degree of the compressor when the heat pump water heater is in the bathtub insulation mode;

The determining module 502 is further configured to determine a third target opening of the second electronic expansion valve according to a second suction superheat degree of the compressor and a target superheat degree of the compressor; the third target opening enables the difference value between the water temperature in the bathtub and the first target water temperature to be smaller than the first preset value;

the control module 503 is further configured to control the second electronic expansion valve to open to the third target opening degree.

In one possible implementation, the control module 503 is further configured to control the heat pump water heater to enter a bathtub keep warm mode in response to an operation instruction.

the obtaining module 501 is further configured to obtain a water level in the bathtub collected by the water level detecting device, and collect a duration of a target object in the preset range of the bathtub by the human body detecting device;

the control module 503 is further configured to control the heat pump water heater to enter a bathtub thermal insulation mode when the water level in the bathtub is greater than or equal to a preset water level, and the duration time of the human body detection device for collecting the target object in the preset range of the bathtub is longer than a preset duration time.

The temperature control device provided by the embodiment of the application can execute the technical scheme shown in the embodiment of the method, and has similar principle and beneficial effects, and the description is omitted here.

Fig. 6 is a schematic hardware structure of a temperature control device according to an embodiment of the present application. Referring to fig. 6, the temperature control apparatus 600 may include: a processor 601 and a memory 602, wherein the processor 601 and the memory 602 may communicate; illustratively, the processor 601 and the memory 602 are in communication via a communication bus 603, said memory 602 being adapted to store a computer program, said processor 601 being adapted to invoke the computer program in the memory 602 to perform the temperature control method as shown in any of the method embodiments described above.

Optionally, the temperature control device 600 may also include a communication interface, which may include a transmitter and/or a receiver.

Alternatively, the processor may be a central processing unit (Central Processing Unit, CPU), but may also be other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present application may be embodied directly in a hardware processor for execution, or in a combination of hardware and software modules in the processor for execution.

Alternatively, the temperature control device 600 in the embodiment of the present application may be a control device in a heat pump water heater, which may include a circuit board, and electrical devices such as a processing chip and a memory chip disposed on the circuit board, so as to implement the temperature control method shown in any method embodiment.

An embodiment of the present application provides a heat pump water heater including a temperature control apparatus as shown in fig. 6.

The embodiment of the application also provides bathroom equipment, which comprises a heat pump water heater, the temperature control equipment in the third aspect and a bathtub.

Embodiments of the present application provide a computer-readable storage medium having stored thereon computer-executable instructions; the computer-executable instructions, when executed by a processor, are for implementing the temperature control method as described in any of the embodiments above.

An embodiment of the application provides a computer program product comprising a computer program which, when executed by a processor, implements a temperature control method as described in any of the embodiments above.

In the several embodiments provided by the present application, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in hardware plus software functional units.

The integrated units implemented in the form of software functional units described above may be stored in a computer readable storage medium. The software functional unit is stored in a storage medium, and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor (processor) to perform part of the steps of the methods according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional modules is illustrated, and in practical application, the above-described functional allocation may be performed by different functional modules according to needs, i.e. the internal structure of the apparatus is divided into different functional modules to perform all or part of the functions described above. The specific working process of the above-described device may refer to the corresponding process in the foregoing method embodiment, which is not described herein again.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application.

Claims

1. A method of temperature control, characterized in that a heat pump water heater comprises: the heat exchanger is arranged on a refrigerant passage between the evaporator and the condenser and is arranged on the outer wall surface of the bathtub, and the first electronic expansion valve is arranged on the refrigerant passage between the heat exchanger and the condenser;

The method comprises the following steps:

when the heat pump water heater is in a bathtub heat preservation mode, acquiring the refrigerant temperature of the heat exchanger and the water temperature in the bathtub;

controlling the first electronic expansion valve to be opened to a first target opening degree;

the first target water temperature is greater than or equal to a preset temperature; the method further comprises the steps of:

2. The method of claim 1, wherein determining the first target opening of the first electronic expansion valve based on the coolant temperature, the water temperature in the bathtub, the coolant saturation temperature of the heat exchanger, and the first target water temperature comprises:

3. The method of claim 2, wherein determining the first opening variation of the first electronic expansion valve based on the refrigerant temperature and the refrigerant saturation temperature comprises:

4. A method according to claim 3, wherein said determining the first opening degree variation amount according to the current superheat degree of the heat exchanger and the target superheat degree of the heat exchanger includes:

And determining the first opening variation according to the current superheat degree of the heat exchanger, the target superheat degree of the heat exchanger and the mapping relation among the superheat degree, the target superheat degree and the opening variation.

5. The method of any one of claims 1-4, wherein the heat pump water heater further comprises: the external surface of the water tank is in contact with the condenser, the second electronic expansion valve is arranged on a refrigerant passage between the heat exchanger and the evaporator, and the compressor is arranged on the refrigerant passage between the evaporator and the condenser;

the method further comprises the steps of:

when the heat pump water heater is in a water tank heating mode, acquiring a first suction superheat degree of the compressor;

controlling the first electronic expansion valve to be opened to the second target opening degree;

And controlling the second electronic expansion valve to be opened to a preset opening degree.

6. The method of claim 5, wherein the method further comprises:

7. The method according to any one of claims 1-4, further comprising:

responding to an operation instruction, and controlling the heat pump water heater to enter a bathtub heat preservation mode;

or alternatively, the process may be performed,

the heat pump water heater further comprises: the water level detection device is arranged in the bathtub, and the human body detection device is arranged on the outer wall surface of the bathtub;

8. A temperature control device, characterized in that a heat pump water heater comprises: the heat exchanger is arranged on a refrigerant passage between the evaporator and the condenser and is arranged on the outer wall surface of the bathtub, and the first electronic expansion valve is arranged on the refrigerant passage between the heat exchanger and the condenser;

the temperature control device comprises an acquisition module, a determination module, a control module and an adjustment module;

the acquisition module is used for acquiring the refrigerant temperature of the heat exchanger and the water temperature in the bathtub when the heat pump water heater is in a bathtub heat preservation mode;

the determining module is configured to determine, if the water temperature in the bathtub is less than a first target water temperature of the bathtub and a difference value between the water temperature in the bathtub and the first target water temperature is greater than or equal to a first preset value, a first target opening of the first electronic expansion valve according to the refrigerant temperature, the water temperature in the bathtub, the refrigerant saturation temperature of the heat exchanger, and the first target water temperature; the first target opening enables the difference value between the water temperature in the bathtub and the first target water temperature to be smaller than the first preset value;

The control module is used for controlling the first electronic expansion valve to be opened to a first target opening degree;

the first target water temperature is greater than or equal to a preset temperature, and the adjusting module is used for adjusting the first target water temperature to a second target water temperature when the first electronic expansion valve is controlled to keep the first target opening for a preset time period, wherein the second target water temperature is smaller than the preset temperature;

9. A temperature control apparatus, characterized by comprising: a processor and a memory;

the memory is used for storing a computer program;

the processor is configured to execute a computer program stored in the memory to implement the temperature control method according to any one of claims 1 to 7.

10. A computer readable storage medium, characterized in that the computer readable storage medium has stored therein computer executable instructions for implementing the temperature control method according to any one of claims 1 to 7 when executed by a processor.

11. A computer program product comprising a computer program which, when executed by a processor, implements the temperature control method according to any one of claims 1 to 7.