Heat pump unit and its pipe network calibration method, actual operating environment determination method

Abstract

The present invention relates to a heat pump unit and a pipe network calibration method and an actual operation environment determination method. Before the first operation, the pipe network calibration operation is performed according to a preset pipe network calibration program. Under the pipe network calibration program, the pipe network characteristic point is indirectly calculated according to the operation state of the water pump, and multiple pipe network characteristic points are obtained according to multiple water pump calibration operations at different speeds. The pipe network characteristic curve is generated by fitting according to the obtained multiple pipe network characteristic points. This scheme can adjust the pipe network characteristic curve according to the actual operation environment of the hot water supply unit, and control the unit operation according to the adjusted pipe network characteristic curve to make it conform to the actual operation environment of the unit.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump heating systems, and in particular to a heat pump unit and a pipe network calibration method thereof, and a method for determining an actual operating environment. Background Art

[0002] As people's living standards continue to improve, heat pump water heaters have been widely used in home environments. The following problems may occur during the installation and use of heat pump water heaters:

[0003] Installation process problems:

[0004] The built-in water pump of the heat pump hot water unit does not match the installation environment, and the water pump operating point deviates from the optimal working range, resulting in the water pump circulating flow being too large and the lift being too small, or the water pump circulating flow being too small and the lift being too large.

[0005] The above situation will lead to the following problems:

[0006] The pump's operating efficiency is reduced and power consumption is increased;

[0007] In severe cases, the life of the water pump will be shortened or even the water pump will burn out.

[0008] Therefore, it is very necessary to identify the actual operating conditions of the water pump at the initial installation of the hot water unit.

[0009] Problems during use:

[0010] As the heating unit is used for a longer time, scaling will inevitably occur inside the hot water pipe network, hot water circulation pump, and refrigerant-water heat exchanger.

[0011] Due to the non-uniform installation environment of hot water supply units, existing hot water supply units are unable to detect scaling conditions within the system according to the actual installation environment, which increases the complexity of the unit's use and maintenance process.

[0012] Scaling will lead to the following problems:

[0013] The inner diameter of the hot water transmission pipe network is reduced, and the circulating water volume is reduced, which affects the use effect of the heating terminal;

[0014] The hot water circulation pump's operating point changes, the water supply circulation pump's flow rate decreases, and the water supply pressure head increases, which may cause the water pump to burn out in severe cases;

[0015] Scaling on the water side of the refrigerant-water heat exchanger increases the heat exchange thermal resistance and reduces the operating efficiency of the unit.

[0016] Therefore, how to detect the scaling inside the heating pipe network has become an important monitoring object during the operation of the hot water supply unit. The prior art does not provide an effective solution to the above problem. Summary of the invention

[0017] In order to solve the above problems, one of the purposes of the present invention is to provide a pipe network calibration method for a heat pump unit, comprising:

[0018] When the unit is detected to be running for the first time, the pipe network calibration operation mode is entered. In the pipe network calibration operation mode, the heat pump heating unit is controlled to operate for a preset number of times X as follows, where X is a natural number ≥ 1;

[0019] For the nth operation, follow the steps below, where n=1, ..., X:

[0020] Control the water pump to operate at a preset speed Rn, and obtain the water pump operating power Nn and the operating efficiency ηn of the water pump at the current speed; wherein Rn is the water pump speed for the nth time, the water pump speed is different for each operation, and the water pump allows a minimum speed and a maximum speed range, Nn is the actual operating power of the water pump for the nth time, and a one-to-one correspondence is established between Rn and ηn in advance;

[0021] According to the relationship between the circulating water volume G, the pump head H and the pump operation efficiency ηn, the product value GH of the circulating water volume G and the pump head H is determined. According to the GH value, combined with the preset pump characteristic curve, the pipe network characteristic point an of the specific pipe network under the current working conditions is calculated and saved;

[0022] After executing X times, the pipe network characteristic curve of the specific pipe network after calibrating is fitted according to the pipe network characteristic points a1-an, and the operation of the water pump is controlled according to the calibrated pipe network characteristic curve.

[0023] Another object of the present application is to provide a method for determining the actual operating environment of a heat pump unit, wherein the unit has several operating modes, namely, hot water operation, cooling water operation and defrosting operation, including:

[0024] When the unit is operated for the first time, a calibrated pipe network characteristic curve is obtained according to the pipe network calibration method of a heat pump unit as described above;

[0025] Control the operation of the water pump according to the calibrated pipe network characteristic curve and detect the current pipe network characteristic point;

[0026] During the hot water production operation, if the current pipe network characteristic point deviates from the calibrated pipe network characteristic curve, it can be judged that the internal scaling of the unit is serious, and a descaling reminder is given;

[0027] During the cooling water or defrosting operation, if the current pipe network characteristic point deviates from the calibrated pipe network characteristic curve, it can be determined that there is a risk of freezing on the water side of the unit's refrigerant-water heat exchanger.

[0028] Another object of the present application is to provide a heat pump unit, comprising a circulating water pump and a control mechanism, wherein the control mechanism executes the actual operating environment determination method of the heat pump unit as described above.

[0029] Since the present application adopts the above scheme, it can perform pipe network calibration operation according to the preset pipe network calibration procedure before the first operation. The calibration method is that the water pump runs for a certain period of time at multiple speeds (covering the minimum speed and maximum speed range allowed by the water pump), and indirectly calculates the pipe network characteristic points according to the running state of the water pump, obtains multiple pipe network characteristic points according to multiple calibration operations of the water pump at different speeds, and generates a pipe network characteristic curve by fitting according to the obtained multiple pipe network characteristic points. In this way, it is possible to adjust the pipe network characteristic curve according to the actual operating environment of the hot water supply unit, and control the unit operation according to the adjusted pipe network characteristic curve to make it conform to the actual operating environment of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the structure of the hot water supply unit involved in this application;

[0031] Figure 2 This is a schematic diagram of the control structure involved in this application;

[0032] Figure 3 This is a schematic diagram of the characteristics of the water pump-hot water pipe network involved in this application;

[0033] Figure 4 This is a control logic diagram of the hot water supply unit involved in this application. DETAILED DESCRIPTION

[0034] The embodiments of the present invention are described in detail below.

[0035] Example 1

[0036] like Figure 1 As shown, the heat pump unit involved in this embodiment is a hot water supply unit, and the hot water supply unit 1 is composed of a refrigerant heat source part 10, a water circulation-heat exchange part 20, a control mechanism 30 and a heat-using side (not shown).

[0037] The hot water supply unit 1 is composed of a compressor 101 , a four-way reversing valve 102 , a throttling mechanism 103 , a refrigerant-air heat exchanger 104 and a fan 105 .

[0038] The compressor 101 can compress the low-temperature and low-pressure refrigerant into the high-temperature and high-pressure refrigerant, and provide power for the refrigerant to circulate in the pipeline.

[0039] The four-way reversing valve 202 has a refrigeration (defrosting) operation mode (at this time, the refrigerant flow path in the four-way reversing valve 102 is as follows Figure 1 The dotted line in the middle) and the heating operation mode (at this time, the refrigerant flow path in the four-way reversing valve 102 is as shown in FIG. Figure 1 (shown by the solid line).

[0040] The throttling mechanism 103 can throttle the high-temperature and high-pressure refrigerant to a low-temperature and low-pressure refrigerant.

[0041] The refrigerant-air heat exchanger 104 absorbs heat from the outdoor space where the outdoor unit 20 of the hot water supply unit is located when the hot water supply unit is in the heating operation process.

[0042] The fan 105 can allow air to pass through the refrigerant-air heat exchanger 104 to enhance the heat exchange efficiency of the air side of the refrigerant-air heat exchanger 104 .

[0043] The water circulation-heat exchange part 20 is composed of a refrigerant-water heat exchanger 201 , a circulating water pump 202 , a water temperature sensor 203 , a water return port 204 and a water outlet 205 .

[0044] The refrigerant-water heat exchanger 201 can realize heat transfer between the refrigerant and water.

[0045] The circulating water pump 202 can provide circulating power for the water inside the hot water pipe network.

[0046] The water temperature sensor 203 can detect the water temperature.

[0047] The water return port 204 and the water outlet port 205 are connected to the water outlet pipe on the heat-using side and the water inlet pipe on the heat-using side respectively.

[0048] The control mechanism 30 can collect the operating status of each component in the water heater unit 1 and can adjust the operating status of each component.

[0049] like Figure 2 As shown, the control mechanism 30 involved in the present invention is composed of an operation information acquisition module 301 , an operation state control module 302 , an operation state judgment module 303 , and a parameter storage module 304 .

[0050] The operation information acquisition module 301 can collect the operation status information of the hot water supply unit (such as the operation power and operation speed of the circulating water pump 202).

[0051] The operation state control module 302 can control the operation state of the hot water supply unit.

[0052] The operating state judgment module 303 can judge the operating state of the hot water supply unit.

[0053] The parameter storage module 304 can store the operating characteristic curve of the circulating water pump 202 and can store the pipe network characteristic parameters collected during the actual operation.

[0054] Figure 3 The characteristics of the circulating water pump 202 at four speeds (R1, R2, R3, R4) and two pipe networks (pipe network A and pipe network B) are provided, wherein the characteristic curve a1a2a3a4 of pipe network A (or the characteristic curve b1b2b3b4 of pipe network B) is the key information to be obtained by the present invention.

[0055] The characteristic curves (F1, F2, F3, F4) of the circulating water pump 202 at four speeds (R1, R2, R3, R4) are factory preset. The number of this group of curves can be increased or decreased according to the progress requirements of the pipeline network characteristic curve. In this implementation case, four curves are used as examples.

[0056] The operating power of the water pump can be calculated by formula 1:

[0057] (Formula 1)

[0058] in:

[0059] N: water pump power, in kW, which can be obtained by the control mechanism 30 during actual operation;

[0060] G: Water circulation volume of water pump: m3 / h;

[0061] H: pump head, m;

[0062] η: Pump efficiency.

[0063] Among them, the water pump efficiencies η1, η2, η3, and η4 of the circulating water pump 202 at four speeds (R1, R2, R3, and R4) are fixed values ​​(pre-stored at the factory).

[0064] According to formula 1, we can get formula 2:

[0065] (Formula 2)

[0066] Therefore, the product GH of the pump circulating water volume G and the pump head H can be calculated based on the detected power N during actual operation and the factory preset pump efficiency η.

[0067] Since the pump characteristic curve (such as F1, F2, F3, F4) can be expressed as the relationship between G and H, the pipe network characteristic points a1, a2, a3, a4 of the pump under the A pipe network at the speeds of R1, R2, R3, R4 can be obtained according to the above method (these can be calculated by iteration method based on the GH value and the pump characteristic curve). Therefore, the characteristic curve a1a2a3a4 of pipe network A can be obtained by fitting the pipe network characteristic points a1, a2, a3, a4. Similarly, the characteristic curve b1b2b3b4 of pipe network B can also be obtained.

[0068] like Figure 4 As shown, the method for obtaining the circulating water pump-pipeline network operating environment of the hot water supply unit involved in the present invention consists of 22 steps from S1 to S22. Here, the pipeline A is taken as an example and the water pump is calibrated and operated at 4 speeds (R1, R2, R3, R4) for explanation. Each operation step is described in detail below.

[0069] Step S1: start the program, then go to step S2;

[0070] Step S2: Determine whether the hot water unit has received a power-on signal. If so, proceed to step S3; otherwise, proceed to step S22;

[0071] Step S3: Determine whether the unit is running for the first time. If the unit is running for the first time, proceed to step S4; otherwise, proceed to step S22;

[0072] Step S4: set n=0, t=0, and then proceed to step S5;

[0073] Step S5: set n=n+1, and then proceed to step S6;

[0074] Step S6: Compare n with a preset threshold, if n=b, proceed to step S20, otherwise proceed to step S7;

[0075] Step S7: Count the time t, and the water pump runs at a preset speed Rn, and then proceed to step S8;

[0076] Step S8: Compare the statistical time t with the preset judgment threshold a, if t≥a, proceed to step S9, otherwise proceed to step S7;

[0077] Step S9: Obtain the operating power Nn of the water pump, obtain the operating efficiency ηn of the water pump at the current speed, set t=0, and then proceed to step S10;

[0078] In the embodiment, the actual water pump operating power can be obtained by detecting the input voltage and input current or directly using a power meter or other methods. In this embodiment, it is preferred to directly determine the water pump operating power by detecting the input voltage and input current.

[0079] Step S10: According to Calculate the product value of the circulating water volume G and the water pump head H, and then enter S11;

[0080] In the embodiment, the characteristic curve of the water pump is often preset at the factory (the relationship between G and H is known). Since the product value of GH can be obtained according to Formula 2, the G value can be assumed here, and the G value can be substituted into the factory-preset water pump characteristic curve to obtain the H value under the assumed G value. If the H value calculated by the assumption is the same as the H value of the water pump characteristic curve under the G value condition, then the assumed point is considered to be the current actual operating point, otherwise it is re-assumed until the calculated H value is equal to the H value of the corresponding water pump characteristic curve under the assumed G condition (this process is an iterative calculation process).

[0081] Step S11: According to the GH value and in combination with the preset pump characteristic curve, the characteristic point an of the pipe network A under the current working condition is calculated and saved, and then the process proceeds to step S12;

[0082] In the embodiment, the characteristic curve of the water pump is often preset at the factory, and the relationship between G and H is known. Since the product value of GH can be obtained according to Formula 2, the G value can be assumed here, and the G value can be substituted into the factory preset water pump characteristic curve to obtain the H value under the assumed G value. If the H value calculated by the assumption is the same as the H value of the water pump characteristic curve under the G value condition, then the assumed point is considered to be the current actual operating point, otherwise it is re-assumed until the calculated H value is equal to the H value of the corresponding water pump characteristic curve under the assumed G condition; this process is an iterative calculation process.

[0083] Step S12: Determine whether n is equal to 1, if n=1, go to step S14, otherwise go to step S13;

[0084] Step S13: Determine whether n is equal to 4, if n=4, proceed to step S17, otherwise proceed to step S5;

[0085] Step S14: output G1, and then go to step S15;

[0086] Step S15: Compare the value of G1 with the product of α and Gmax (α×Gmax). If G1>α×Gmax, proceed to step S16, otherwise proceed to step S5; Step S16: Remind the user that the water pump is in an overflow state (the user needs to replace the water pump or adjust the pipe network design), and then proceed to step S22;

[0087] Step S17: output G4, and then go to step S18;

[0088] Step S18: Compare the value of G4 with the product of β and Gmin, β×Gmin. If G4<β×Gmin, proceed to step S19; otherwise, proceed to step S5.

[0089] Step S19: remind the user that the water pump is in a state of too low flow (the user needs to replace the water pump or adjust the pipe network design), and then proceed to step S22;

[0090] Step S14-Step S19, n=1 is the minimum flow point, this point determines whether the pump head exceeds the reasonable range (the pump load is too high), n=4 is the maximum flow point, this point determines whether the pump head is too small (there is a risk of pump surge), generally, protection is provided for these two situations.

[0091] Step S20: fitting the pipe network characteristic curve according to the calculated n pipe network characteristic points, and then proceeding to step S21;

[0092] Step S21: save the pipe network characteristic curve, and then proceed to step S22;

[0093] Step S22: End the program.

[0094] Explanation of symbols:

[0095] n: Pipeline network calibration operation sequence number statistical parameter, in this implementation case, n can take values ​​of 0, 1, 2, 3, 4;

[0096] Rn: water pump operating speed, the value of n is the same as the statistical parameter of the pipe network calibration operation sequence number. In this implementation case, the water pump operating speed can be R1, R2, R3, R4, where R1, R2, R3, R4 are preset speed values, such as R1=2000rpm, R2=1500rpm, R3=1000rpm, R4=500rpm;

[0097] t: time statistical parameter;

[0098] a: preset time judgment threshold, such as a is preset to 5 minutes;

[0099] b: preset calibration times statistical threshold, for example, in this implementation case, the water pump is calibrated once at each of the R1, R2, R3, and R4 speeds, and b can be preset to 5;

[0100] ηn: preset water pump operating efficiency, the value of n is the same as the statistical parameter of the pipe network calibration operation sequence number. In this implementation case, the water pump operating efficiency can be η1, η2, η3, η4, where η1, η2, η3, η4 are preset speed values, such as η1=90%, η2=95%, η3=85%, η4=80%;

[0101] Nn: circulating water pump power consumption, n value is the same as the pipe network calibration operation sequence number statistical parameter, in this implementation case, the water pump power consumption can be N1, N2, N3, N4, where N1, N2, N3, N4 values ​​are actually measured during the operation of the water pump;

[0102] an: The calculated nth characteristic point of the pipe network A, the value of n is the same as the statistical parameter of the pipe network calibration operation sequence number (the value of n is 1, 2, 3, 4);

[0103] Gmax: Maximum flow rate in the optimal working range of the water pump (related to the characteristics of the water pump, this value is preset at the factory), m3 / h;

[0104] Gmin: minimum flow rate in the optimal working range of the water pump (related to the characteristics of the water pump, this value is preset at the factory), m3 / h;

[0105] α: The maximum flow correction factor allowed by the water pump. In this implementation case, α can be selected as 120%;

[0106] β: The minimum flow correction factor allowed by the pump. In this implementation case, β can be selected as 80%.

[0107] Example 2

[0108] This embodiment provides a method for determining the actual operating environment of a heat pump unit, wherein the unit has several operating modes, namely, hot water operation, cooling water operation and defrosting operation, and is characterized by comprising:

[0109] When the unit is operated for the first time, a calibrated pipe network characteristic curve is obtained according to a pipe network calibration method for a heat pump water heating unit as shown in Example 1;

[0110] Control the operation of the water pump according to the calibrated pipe network characteristic curve and detect the current pipe network characteristic point;

[0111] During the hot water production operation, if the current pipe network characteristic point deviates from the calibrated pipe network characteristic curve, it can be judged that the internal scaling of the unit is serious, and a descaling reminder is given;

[0112] During the cooling water or defrosting operation, if the current pipe network characteristic point deviates from the calibrated pipe network characteristic curve, it can be determined that there is a risk of freezing on the water side of the unit's refrigerant-water heat exchanger.

[0113] In addition, during the normal operation of the unit, if the pipe network characteristic point quickly deviates from the calibrated pipe network characteristic curve in a short period of time, it can be judged that the unit has a risk of circulating water leakage. The normal operation process of the unit described here refers to the normal operation of the unit during hot water production, cooling water and defrosting operations.

[0114] The method also includes, in a pipe network calibration operation mode, respectively obtaining the pump head at the minimum flow point of the pump and the pump head at the maximum flow point of the pump, and determining whether the operating point of the circulating water pump deviates from the optimal operating range of the pump based on the pump head at the minimum flow point of the pump, the pump head at the maximum flow point of the pump and a preset optimal operating range of the pump; if so, issuing a reminder to adjust the pump configuration or change the pipe network conditions.

[0115] The judgment basis of a method for determining the actual operating environment of a heat pump water heating unit is as follows: Generally, after the installation of the unit in the project is completed, the pipe network conditions will not be changed at will (except in special cases. In special cases, when the pipeline configuration needs to be adjusted, recalibration is required after the adjustment is completed). The change of the pipe network environment is generally only affected by scaling. Therefore, during the operation of the unit to make hot water, if the current pipe network characteristic point deviates from the calibrated pipe network characteristic curve, it can be judged that the internal scaling of the unit is serious, and a descaling reminder is given; during the defrosting process of the unit, the refrigerant will absorb heat from the water side of the refrigerant-water heat exchanger. If freezing occurs, it will cause the local flow resistance on the water side to increase, thereby changing the current characteristics. This method can judge the risk of freezing; after the installation of the unit, the change of the pipe network characteristics is often due to the scaling inside the pipe network, which causes the circulation environment of the circulating water to change. This process is often carried out slowly. If the current characteristics deviate from the predetermined curve in a short period of time, it is generally believed that there is a leak somewhere in the pipe network. In some embodiments, if the unit itself sets a descaling operation mode, it can also switch to the descaling operation mode when it is judged that the internal scaling of the unit is serious.

[0116] Example 3

[0117] The difference between this embodiment and embodiment 1 is that the heat pump unit in this embodiment also runs a method for determining the actual operating environment of the heat pump unit as described in embodiment 2.

[0118] Through the above scheme, the present invention can adjust the pipe network characteristic curve according to the actual operating environment of the hot water supply unit at the initial stage of installation, and control the unit operation according to the adjusted pipe network characteristic curve to make it conform to the actual operating environment of the unit. And effectively monitor the scaling problem inside the unit and the hot water pipe network during the use of the unit.

[0119] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A pipe network calibration method for a heat pump unit, characterized in that: include: When the unit is detected to be running for the first time, the pipe network calibration operation mode is entered. In the pipe network calibration operation mode, the heat pump heating unit is controlled to operate a preset number of times X, where X is a natural number ≥ 1; For the nth operation, the following steps are performed, where n=1, ..., X: Control the water pump to run at the preset speed Rn, obtain the water pump operating power Nn and the water pump operating efficiency ηn at the current speed; where Rn is the nth water pump speed, and the water pump speed is different each time and covers the minimum and maximum allowable speed ranges of the water pump. Nn is the actual operating power of the pump for the nth time, and a one-to-one correspondence is established between Rn and ηn in advance; According to the relationship between the circulating water volume G of the water pump, the water pump head H and the water pump operation efficiency ηn, the product value GH of the circulating water volume G and the water pump head H is determined, wherein the product value GH of the circulating water volume G and the water pump head H is determined as follows: GH=367.3Nη The pump operating power N is determined according to the current operating parameters of the pump, or directly detected by a power meter, and the unit is kW; η is determined according to the current pump operating speed and the corresponding relationship between the preset pump operating speed and operating efficiency; the pump circulating water volume G is in m 3 / h; the unit of water pump head H is m; According to the GH value, combined with the preset water pump characteristic curve, the pipe network characteristic point an of the specific pipe network under the current working condition is calculated and saved. Specifically, by assuming the G value, the G value is brought into the factory preset water pump characteristic curve to obtain the H value under the assumed G value. If the H value calculated by the assumption is the same as the H value of the water pump characteristic curve under the G value condition, the assumed point is considered to be the current actual operating point; Otherwise, adjust the G value, and iterate the above process until the calculated H value is equal to the H value of the corresponding water pump characteristic curve under the assumed G value condition; after executing X times, the pipe network characteristic curve of the specific pipe network after calibrating is fitted according to the pipe network characteristic points a1-an, and the water pump operation is controlled according to the calibrated pipe network characteristic curve.

2. A pipe network calibration method for a heat pump unit according to claim 1, characterized in that: Before fitting the pipe network characteristic curve of the specific pipe network, the method further includes the following steps: According to the GH value of the first operation in the pipe network calibration operation mode, determine the circulating water volume G1 of the pump this time. If G1>α×Gmax, an over-flow operation alarm of the pump is given and the unit is controlled to end operation; According to the GH value of the Xth operation in the pipe network calibration operation mode, the circulating water volume GX of the pump is determined. If GX<β×Gmin, an alarm of too low flow rate of the pump is given and the unit is controlled to stop operation; Among them, Gmax is the maximum flow rate in the optimal working range of the water pump, Gmin is the minimum flow rate in the optimal working range of the water pump, α is the maximum allowable flow correction coefficient of the water pump, β is the minimum allowable flow correction coefficient of the water pump, the circulating water volume G1 of the water pump during the first operation is the minimum flow point of the water pump, and the circulating water volume GX of the water pump during the Xth operation is the maximum flow point of the water pump.

3. The pipe network calibration method of a heat pump unit according to claim 1, characterized in that: For the nth operation, the water pump is controlled to operate at a preset speed Rn for a preset time t, and then the step of obtaining corresponding parameters is executed.

4. A pipe network calibration method for a heat pump unit according to claim 1, characterized in that: The current water pump operating power N is determined based on the detected input voltage and input current of the water pump.

5. A method for determining the actual operating environment of a heat pump unit, wherein the unit has several operating modes: hot water operation, cooling water operation and defrosting operation, characterized in that: include: When the unit is operated for the first time, a calibrated pipe network characteristic curve is obtained according to a pipe network calibration method for a heat pump unit according to any one of claims 1 to 4; Control the operation of the water pump according to the calibrated pipe network characteristic curve and detect the current pipe network characteristic point; During the hot water production operation, if the current pipe network characteristic point deviates from the calibrated pipe network characteristic curve, it can be judged that the internal scaling of the unit is serious, and a descaling reminder is given; During the cooling water or defrosting operation, if the current pipe network characteristic point deviates from the calibrated pipe network characteristic curve, it can be determined that there is a risk of freezing on the water side of the unit's refrigerant-water heat exchanger.

6. A method for determining the actual operating environment of a heat pump unit according to claim 5, characterized in that: The method also includes that during normal operation of the unit, if the network characteristic points quickly deviate from the calibrated network characteristic curve within a short period of time, it can be determined that the unit has a risk of circulating water leakage.

7. A method for determining the actual operating environment of a heat pump unit according to claim 5, characterized in that: The method also includes, in a pipe network calibration operation mode, respectively obtaining the pump head at the minimum flow point of the pump and the pump head at the maximum flow point of the pump, and determining whether the operating point of the circulating water pump deviates from the optimal operating range of the pump based on the pump head at the minimum flow point of the pump, the pump head at the maximum flow point of the pump and a preset optimal operating range of the pump; if so, issuing a reminder to adjust the pump configuration or change the pipe network conditions.

8. A heat pump unit, comprising a circulating water pump and a control mechanism, characterized in that: The control mechanism executes the actual operating environment determination method of the heat pump unit according to any one of claims 5 to 7.

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