阅读说明：本技术 一种空气源热泵机组 (Air source heat pump unit ) 是由 颜鹏 孙杨 胡淑珍 于 2021-07-02 设计创作，主要内容包括：本发明公开一种空气源热泵机组,包括：空调模块：由压缩机、四通阀、室外换热器、中间换热器通过冷媒管路连接形成,在冷媒管路上配置有室外电子控制元件；水模块,至少由动力元件、中间换热器通过连接水管连接构成,压缩机排出的冷媒与从连接水管引入的水在中间换热器内进行热交换；主控器,与所述压缩机、动力元件和室外电子控制元件通讯连接,其配置为：在检测到压缩机开机持续运行时间大于第一预设时间且压缩机排气侧温度小于连接水管上的入水水温时,至少能够控制室外电子控制元件的开度增大,控制压缩机的升频速率减小,以及控制所述动力元件转速减小。通过本发明解决了现有技术中空气源热泵机组在制取热水时容易存在压缩机抽真空现象的问题。(The invention discloses an air source heat pump unit, comprising: an air conditioning module: the outdoor heat exchanger is formed by connecting a compressor, a four-way valve, an outdoor heat exchanger and an intermediate heat exchanger through a refrigerant pipeline, and an outdoor electronic control element is arranged on the refrigerant pipeline; the water module is formed by connecting at least a power element and an intermediate heat exchanger through a connecting water pipe, and the refrigerant discharged by the compressor and the water introduced from the connecting water pipe exchange heat in the intermediate heat exchanger; a master controller in communication with the compressor, power element and outdoor electronic control element, configured to: when detecting that the starting up continuous operation time of the compressor is greater than the first preset time and the temperature of the exhaust side of the compressor is less than the temperature of inlet water on a connecting water pipe, the method at least can control the opening of an outdoor electronic control element to be increased, control the frequency increasing rate of the compressor to be reduced, and control the rotating speed of the power element to be reduced. The invention solves the problem that the prior air source heat pump unit is easy to have the phenomenon of vacuumizing a compressor when hot water is prepared.)

1. An air source heat pump unit comprising:

an air conditioning module: the outdoor heat exchanger is formed by connecting a compressor, a four-way valve, an outdoor heat exchanger and an intermediate heat exchanger through a refrigerant pipeline, and an outdoor electronic control element is arranged on the refrigerant pipeline;

the water module is formed by connecting at least a power element and an intermediate heat exchanger through a connecting water pipe, and the refrigerant discharged by the compressor and the water introduced from the connecting water pipe exchange heat in the intermediate heat exchanger;

a master controller in communication with the compressor, power element and outdoor electronic control element, configured to: when detecting that the starting up continuous operation time of the compressor is greater than a first preset time and the temperature of the exhaust side of the compressor is less than the temperature of inlet water on a connecting water pipe, at least the opening of the outdoor electronic control element can be controlled to be increased, the frequency increasing rate of the compressor is reduced, and the rotating speed of the power element is reduced.

2. The air source heat pump unit of claim 1, wherein: when the startup duration time of the compressor is detected to be greater than a first preset time and the temperature of the exhaust side of the compressor is detected to be less than the temperature of inlet water on a connecting water pipe, the opening degree of the outdoor electronic control element is controlled to be completely opened, the frequency increasing rate of the compressor is reduced to a first preset rate, and the rotating speed of the power element is reduced to a first preset rotating speed.

3. The air source heat pump unit of claim 2, wherein: the master is configured to: when the temperature of the exhaust side of the compressor is detected to be higher than the sum of the water inlet temperature and a first preset value on the connecting water pipe, controlling an outdoor electronic control element to descend to a preset opening degree, controlling the frequency rising rate of the compressor to rise to a second preset rate, and controlling the rotating speed of the power element to rise to a second preset rotating speed, wherein the second preset rate is higher than the first preset rate, and the second preset rotating speed is higher than the first preset rotating speed.

4. The air source heat pump unit of claim 1, wherein: the water tank is communicated with the connecting water pipe, and a tap water inlet and a hot water outlet are formed in the water tank.

5. The air source heat pump unit of claim 4, wherein: the connecting water pipe comprises a water inlet pipe and a water return pipe, and a water temperature detection element for detecting the temperature of inlet water is arranged on the water inlet pipe.

6. The air source heat pump unit of claim 1, wherein: and a first exhaust temperature detection element is arranged on the exhaust side of the compressor and is in communication connection with the main controller.

7. The air source heat pump unit of claim 6, wherein: and a second exhaust temperature detection element is arranged on a refrigerant air pipe between the intermediate heat exchanger and the four-way valve and close to the intermediate heat exchanger, and the second exhaust temperature detection element is in communication connection with the main controller.

8. The air source heat pump unit as claimed in claim 5, wherein the main controller obtains the value of the second exhaust temperature detecting element as the water temperature value when detecting that the difference exists between the values of the first exhaust temperature detecting element and the second exhaust temperature detecting element;

when the first exhaust temperature detection element and the second exhaust temperature detection element are detected to have the same value, the value of any one of the exhaust temperature detection elements is randomly acquired as the intake water temperature value.

9. The air source heat pump unit of claim 5, wherein: the water inlet pipe is also provided with a water flow speed detection element and a water flow pressure detection element, and the water flow speed detection element and the water flow pressure detection element are in communication connection with the main controller.

10. The air source heat pump unit of claim 1, wherein the intermediate heat exchanger is a plate heat exchanger or a coil heat exchanger.

Technical Field

The invention relates to the technical field of air source heat pumps.

Background

The air source heat pump product can meet the requirement of a user on domestic hot water, even can reach the outlet water temperature of 55 ℃, but under the condition that the outdoor environment temperature is extremely low: in the case that the outdoor temperature is-25 ℃, the target water temperature of 55 ℃ is required, the suction pressure is extremely low and the discharge pressure of the compressor is extremely low in the process of starting the unit, and the discharge temperature of the compressor is lower than the inlet water temperature, so that the compressor circulates the refrigerant in an overheating area, the circulation flow of the refrigerant is very small, and the phenomenon of vacuumizing is easy to occur.

Disclosure of Invention

In order to solve the problem that the phenomenon of vacuumizing of a compressor is easy to occur when the air source heat pump unit in the prior art prepares hot water, the invention provides the air source heat pump unit which can correspondingly control the compressor, a power element and an outdoor electronic control element when the water temperature is higher at the water inlet temperature, so that the time for vacuumizing the compressor is shortened.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides an air source heat pump unit, comprising:

an air conditioning module: the outdoor heat exchanger is formed by connecting a compressor, a four-way valve, an outdoor heat exchanger and an intermediate heat exchanger through a refrigerant pipeline, and an outdoor electronic control element is arranged on the refrigerant pipeline.

And the water module is formed by connecting at least a power element and an intermediate heat exchanger through a connecting water pipe, and the refrigerant discharged by the compressor and the water introduced from the connecting water pipe exchange heat in the intermediate heat exchanger.

A master controller in communication with the compressor, power element and outdoor electronic control element, configured to: when detecting that the starting up continuous operation time of the compressor is greater than a first preset time and the temperature of the exhaust side of the compressor is less than the temperature of inlet water on a connecting water pipe, at least the opening of the outdoor electronic control element can be controlled to be increased, the frequency increasing rate of the compressor is reduced, and the rotating speed of the power element is reduced.

In some embodiments of the present application: when the startup duration time of the compressor is detected to be greater than a first preset time and the temperature of the exhaust side of the compressor is detected to be less than the temperature of inlet water on a connecting water pipe, the opening degree of the outdoor electronic control element is controlled to be completely opened, the frequency increasing rate of the compressor is reduced to a first preset rate, and the rotating speed of the power element is reduced to a first preset rotating speed.

In some embodiments of the present application: the master is configured to: when the temperature of the exhaust side of the compressor is detected to be higher than the sum of the water inlet temperature and a first preset value on the connecting water pipe, controlling an outdoor electronic control element to descend to a preset opening degree, controlling the frequency rising rate of the compressor to rise to a second preset rate, and controlling the rotating speed of the power element to rise to a second preset rotating speed, wherein the second preset rate is higher than the first preset rate, and the second preset rotating speed is higher than the first preset rotating speed.

In some embodiments of the present application: the water tank is communicated with the connecting water pipe, and a tap water inlet and a hot water outlet are formed in the water tank.

In some embodiments of the present application: the connecting water pipe comprises a water inlet pipe and a water return pipe, and a water temperature detection element for detecting the temperature of inlet water is arranged on the water inlet pipe.

In some embodiments of the present application: and a first exhaust temperature detection element is arranged on the exhaust side of the compressor and is in communication connection with the main controller.

In some embodiments of the present application: and a second exhaust temperature detection element is arranged on a refrigerant air pipe between the intermediate heat exchanger and the four-way valve and close to the intermediate heat exchanger, and the second exhaust temperature detection element is in communication connection with the main controller.

In some embodiments of the present application: when the main controller detects that the difference value exists between the values of the first exhaust temperature detection element and the second exhaust temperature detection element, the main controller obtains the value of the second exhaust temperature detection element as the water inlet temperature value;

when the first exhaust temperature detection element and the second exhaust temperature detection element are detected to have the same value, the value of any one of the exhaust temperature detection elements is randomly acquired as the intake water temperature value.

In some embodiments of the present application: the water inlet pipe is also provided with a water flow speed detection element and a water flow pressure detection element, and the water flow speed detection element and the water flow pressure detection element are in communication connection with the main controller.

In some embodiments of the present application: the intermediate heat exchanger is a plate heat exchanger or a coil heat exchanger.

Compared with the prior art, the technical scheme of the invention has the following technical effects:

when the air source heat pump unit provided by the invention detects that the temperature of inlet water is higher than the temperature of the exhaust side of the compressor, the outdoor electronic control element can be correspondingly controlled, so that the opening degree of the outdoor electronic control element is increased, the flow of a refrigerant is increased, the raising frequency rate of the compressor is controlled to be reduced, the vacuumizing of the compressor is avoided, and meanwhile, the rotating speed of the power element is reduced, so that the heat of the refrigerant supplied to the air conditioning module is reduced, the air conditioning module enters a normal running state as soon as possible, and the vacuumizing time of the compressor is shortened.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic view showing the operation of an air source heat pump unit according to an embodiment of the present invention;

FIG. 2 is a first schematic view of an air source heat pump unit according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of an air source heat pump unit according to an embodiment of the present invention;

FIG. 4 is a graph showing a variation of a ramp rate curve of a compressor of the air source heat pump unit according to an embodiment of the present invention and a curve corresponding to a suction pressure of the compressor;

FIG. 5 is a graph showing another ramp rate curve of the compressor of the air source heat pump unit according to the embodiment of the present invention and a curve variation corresponding to the suction pressure of the compressor.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

In the description of the present invention, it should be noted that the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected unless otherwise explicitly stated or limited. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art. In the foregoing description of embodiments, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

Example one

The invention provides an embodiment of an air source heat pump unit, which comprises:

an air conditioning module: the outdoor unit is formed by connecting a compressor 110, a four-way valve 120, an outdoor heat exchanger 130, and an intermediate heat exchanger 140 through a refrigerant pipe line, and an outdoor electronic control unit 150 is disposed on the refrigerant pipe line.

In some embodiments of the present application, the outdoor electronic control element 150 is an outdoor electronic expansion valve.

In order to realize gas-liquid separation, the air conditioning module also comprises the following components: the two ends of the gas-liquid separator and the two ends of the gas-liquid separator are respectively connected with the compressor 110 and the four-way valve 120.

And an outdoor fan disposed at the side of the outdoor heat exchanger 130 to dissipate heat of the outdoor unit.

The refrigerant pipeline correspondingly comprises a refrigerant air pipe and a refrigerant liquid pipe, the four-way valve 120 is connected with the intermediate heat exchanger 140 through the refrigerant liquid pipe, the outdoor heat exchanger 130 is connected with the intermediate heat exchanger 140 through the refrigerant air pipe, a liquid detection stop valve is arranged on the refrigerant liquid pipe, an air side stop valve is arranged on the refrigerant air pipe, and an outdoor environment temperature sensor for detecting the environment temperature is arranged outside the outdoor unit.

The on-off control of the refrigerant liquid pipe and the refrigerant gas pipe is realized through the liquid detection stop valve and the gas side stop valve.

In some embodiments of the present application: the intermediate heat exchanger 140 is a plate heat exchanger or a coil heat exchanger.

And a water module at least formed by connecting the power element 210 and the intermediate heat exchanger 140 through a connection water pipe 220, wherein the refrigerant discharged from the compressor 110 and the water introduced from the connection water pipe 220 exchange heat in the intermediate heat exchanger 140.

In some embodiments of the present application, the power element 210 is a circulating water pump.

The intermediate heat exchanger 140, the circulating water pump, and the power element 210 are connected to the connection water pipe 220 to form a water circulation flow path.

In some embodiments of the present application, the connection water pipe 220 includes: comprises a water inlet pipe 221 and a water return pipe 222.

The inlet pipe 221 is provided with a water temperature detecting element 400 for detecting the temperature of the inlet water, and preferably, the water temperature detecting element 400 is a water temperature detecting sensor.

In order to control the on-off of the water inlet pipe 221, a water inlet stop valve is further arranged on the water inlet pipe 221. The inlet pipe 221 is further provided with a safety valve, an exhaust valve, and a filter.

In order to realize the detection of the flow rate of the inflow water and the detection of the inflow water pressure, the air source heat pump unit in this embodiment further includes a water flow rate detection element 710 and a water flow pressure detection element 720, and the water flow rate detection element 710 and the water flow pressure detection element 720.

The water flow rate detecting element 710 is a water flow rate sensor, and the water pressure detecting element 720 is a water pressure sensor.

The water return pipe 222 is provided with a water outlet stop valve, an expansion tank, a water drain valve, and a water outlet temperature detection sensor.

The process of the air conditioning device for producing hot water comprises the following steps: the high-temperature high-pressure gaseous refrigerant is discharged from the compressor 110, passes through the four-way valve 120, and then flows into the intermediate heat exchanger 140 through the refrigerant air pipe, the low-temperature water in the water module flows in from the water inlet pipe 221, and then enters the intermediate heat exchanger 140, the high-temperature high-pressure refrigerant exchanges heat with the low-temperature water flowing into the intermediate heat exchanger 140, the low-temperature water absorbs the heat released by the high-temperature high-pressure refrigerant, the low-temperature water is changed into high-temperature water, and the high-temperature water flows out to meet the needs of users.

The high-temperature refrigerant emits heat and is condensed into a high-pressure liquid refrigerant, the high-temperature liquid refrigerant is throttled into a low-temperature low-pressure refrigerant through an outdoor electronic expansion valve, the low-temperature low-pressure refrigerant is evaporated into a low-pressure superheated refrigerant in the outdoor heat exchanger 130, the low-temperature superheated refrigerant flows into the compressor 110, and the low-temperature superheated refrigerant is discharged by the compressor 110 to perform work, so that the hot water making cycle process is completed.

During the air source heat pump unit, can prepare life hot water through the heat exchange between air conditioner module and the water module, satisfy the user to life hot water's demand, can reach out water temperature 55 ℃ even.

But if the outdoor ambient temperature is extremely low: in the case that the outdoor temperature is-25 ℃, a target water temperature of 55 ℃ is required, the suction pressure is extremely low during the starting process of the unit, the discharge pressure of the compressor 110 is also extremely low, the temperature of the discharge side of the compressor 110 is lower than the temperature of the inlet water, the hot water making system operates, the unit operates at the starting stage, the temperature of the refrigerant is lower than the water temperature during the heat exchange process of the water in the water storage tank 300 and the refrigerant discharged by the compressor 110 in the intermediate heat exchanger 140, and the refrigerant is heated by the water, so that the refrigerant circulation mass flow of the compressor 110 is very small, the compressor 110 is easy to vacuumize, and the operation reliability of the compressor 110 is affected.

The air source heat pump unit provided in this embodiment can control corresponding relevant components in the whole air source heat pump unit when the compressor 110 generates a vacuum pumping phenomenon, so as to avoid the occurrence of the vacuum pumping phenomenon of the compressor 110 as much as possible.

In a specific setting, the main controller is connected with the compressor 110, the power element 210 and the outdoor electronic control element 150 in a communication way.

The master is configured to: when the startup duration time of the compressor 110 is detected to be greater than the first preset time and the temperature of the exhaust side of the compressor 110 is detected to be less than the temperature of the inlet water on the connecting water pipe 220, at least the opening of the outdoor electronic control element 150 can be controlled to be increased, the frequency increasing rate of the compressor 110 is controlled to be reduced, and the rotating speed of the power element 210 is controlled to be reduced.

The first preset time is set as t1min, and t1min is a control preset constant.

After the compressor 110 is turned on and continuously operates for the first preset time, the temperature of the exhaust side of the compressor 110 is still detected to be low, and corresponding control needs to be executed.

When the mass flow rate of the refrigerant flowing and circulating in the air conditioning module is reduced, the opening degree of the outdoor electronic control element 150 can be correspondingly increased, and the flow rate of the refrigerant can be increased by increasing the opening degree of the outdoor electronic control element 150.

The compressor 110 can be operated for a longer time in a normal suction pressure range of the compressor 110 and for a shorter time in an abnormal range by reducing the frequency increase rate of the compressor 110.

When the compressor 110 is in normal operation, the corresponding compressor suction pressure is within the compressor suction pressure interval.

As shown in fig. 3 and 4, the region above the dotted line corresponds to the compressor suction pressure in the normal range, and the region below the dotted line corresponds to the compressor suction pressure in the abnormal range.

As can be seen from fig. 3, when the frequency increasing rate of the compressor 110 is decreased and slowly changed, it corresponds to a long time when the suction pressure of the compressor 110 is in the normal interval of the suction pressure of the compressor and a short time when the suction pressure is in the abnormal interval.

Conversely, when the increasing frequency rate of the compressor 110 increases and the increasing frequency rate changes rapidly, the time that the corresponding compressor suction pressure is in the normal interval range is short, and the time that the compressor suction pressure is in the abnormal interval range is long.

FIG. 4 is a graph representing the ramp rate Δ f1 of the compressor 110 versus the suction pressure of the compressor 110;

FIG. 5 is a graph representing the ramp rate Δ f2 curve for compressor 110 versus the suction pressure of compressor 110;

the ramp-up rate corresponding to Δ f1 is slower and is within the non-normal interval for a time ta, and the ramp-up rate corresponding to Δ f2 is slower and is within the non-normal interval for a time tb, which is seen to be greater than ta.

Therefore, the present embodiment is controlled to decrease the frequency increasing rate of the compressor 110.

The master controller still corresponds simultaneously and controls power element 210, reduce power element 210's rotational speed, and then reduce the discharge through power element 210 driven, after discharge reduces, lie in the rivers of connecting in water pipe 220 and enter into middle heat exchanger 140 back, can provide the heat of refrigerant and reduce, and then make the heat exchange volume of refrigerant few in rivers and the air conditioning module, in order to guarantee the heat that obtains rivers that the refrigerant is as few as possible, make the start-up operation that whole air conditioning module can be quick.

In some embodiments of the present application: when detecting that the continuous operation time of the compressor 110 is longer than a first preset time and the temperature of the exhaust side of the compressor 110 is lower than the temperature of the inlet water on the connecting water pipe 220, the opening degree of the outdoor electronic control element 150 is controlled to be completely opened, the frequency increasing rate of the compressor 110 is increased to a first preset rate, and the rotating speed of the power element 210 is reduced to a first preset rotating speed.

The first preset rate of the frequency rising rate of the compressor 110 is delta F1Hz/s, wherein delta F1 is a preset control constant;

the first predetermined speed of the power element 210 is r1 r/min, wherein r1 is a predetermined control constant.

The outdoor electronic control element 150 is completely turned on, so that the flow of the refrigerant in the whole air conditioning module can be maximized, the problem of low refrigerant circulation mass flow can be quickly solved, and the problem of vacuumizing the compressor 110 can be avoided.

In some embodiments of the present application: the master is configured to: when the temperature of the discharge side of the compressor 110 is detected to be greater than the sum of the water inlet temperature on the connection water pipe 220 and a first preset value, the outdoor electronic control element 150 is controlled to be lowered to a preset opening degree.

The first preset value corresponds to a preset control constant.

The preset opening degree is an initial opening degree in some embodiments of the present application, and may be a preset opening degree value.

When the temperature of the exhaust side of the compressor 110 is higher than the temperature of the inlet water, the air conditioning module can move normally to heat the circulating water in the water module, and at the moment, the air source heat pump unit is controlled to operate normally.

The control of the outdoor electronic control unit 150 may be performed with the degree of superheat of the discharge gas of the compressor 110 as a target.

Correspondingly, the frequency increasing rate of the compressor 110 is controlled to increase to a second preset rate, and the rotating speed of the power element 210 is controlled to increase to a second preset rotating speed, where the second preset rate is greater than the first preset rate, and the second preset rotating speed is greater than the first preset rotating speed.

Wherein, a second preset rotating speed corresponding to the frequency raising rate is set as delta F2Hz/s, and delta F2 is a preset control constant;

the rotating speed of the power element 210 is r2 r/min, and r2 is a preset control constant. DeltaF 1 <. DELTA.F 2, r1 < r 2.

In some embodiments of the present application: the water module further comprises a water tank 300, the water tank 300 is communicated with the connecting water pipe 220, a tap water inlet 310 and a hot water outlet 320 are arranged on the water tank 300, one end of the water tank 300 is connected with the water inlet pipe 221, and the other end of the water tank is connected with the water return pipe 222.

Tap water flows into the water tank 300 through the tap water inlet 310, then flows into the water pipe 221, flows into the intermediate heat exchanger 140 from the water pipe 221, exchanges heat, flows back into the water tank 300, and flows out from the hot water outlet 320 to provide domestic hot water for users.

In some embodiments of the present application: a first exhaust temperature detecting element 500 is disposed on the exhaust side of the compressor 110, and the first exhaust temperature detecting element 500 is in communication connection with the main controller.

The first exhaust temperature detecting element 500 is a first exhaust temperature sensor, which can be used to detect a temperature value on the exhaust side of the compressor 110.

In some embodiments of the present application: a second exhaust temperature detecting element 600 is arranged on a refrigerant gas pipe between the intermediate heat exchanger 140 and the four-way valve 120 and close to the intermediate heat exchanger 140, and the second exhaust temperature detecting element 600 is in communication connection with the main controller.

The second discharge temperature detecting element 600 is a second discharge temperature sensor, and since the first discharge temperature detecting element 500 on the discharge side of the compressor 110 cannot accurately reflect the relationship between the inlet refrigerant temperature and the inlet water temperature of the intermediate heat exchanger 140 if the connection piping between the outdoor unit and the water module is relatively long or the insulation of the connection piping is not good, it is possible to add 1 second discharge temperature detecting element 600 to the position of the refrigerant inlet of the intermediate heat exchanger 140 to detect the temperature of the refrigerant inlet in real time.

When the main controller detects that the values of the first exhaust temperature detection element 500 and the second exhaust temperature detection element 600 have a difference value, the main controller acquires the value of the second exhaust temperature detection element 600 as the water inlet temperature value;

when the first exhaust temperature detecting element 500 and the second exhaust temperature detecting element 600 are detected to have the same value, the value of any one of the exhaust temperature detecting elements is randomly acquired as the intake water temperature value.

In the foregoing description of embodiments, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.