A variable frequency water pump self-adaptive adjusting control method for a heat pump unit

Abstract

The present application relates to a kind of heat pump unit variable frequency water pump adaptive regulation control method.For S1.Obtain the head-flow characteristic curve of variable frequency water pump under each speedS2.According to the number of user end equipment opening, variable frequency water pump is operated to increase frequency and reduce frequency, and the flow and head of variable frequency water pump under each speed are recorded, and the head-flow characteristic curve of current pipeline is fitted out;S3.According to the required water flow determined, the working point in current state and the speed of variable frequency water pump are obtained;S4.According to the flow feedback of each end, after obtaining the best working point in current state, it is verified whether the current water flow of each end meets the rated flow of end;If meet, then execute according to current speed, if not meet, then carry out frequency modulation, until meet.The present application effectively solves the difficulty of head and flow real-time matching, effectively improves the stability and energy efficiency of unit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of two-supply heat pump unit, more particularly, to a variable frequency water pump self-adaptive adjustment control method for heat pump unit. BACKGROUND

[0002] The domestic traditional integrated two-supply heat pump unit has refrigeration and heating functions, and main equipment of the unit includes a compressor, a finned heat exchanger, a double-pipe heat exchanger, a water pump and the like. In the domestic integrated two-supply heat pump unit, a fixed frequency water pump is used by most manufacturers. In the early design stage, the rated flow is calculated according to the rated capacity of the unit, and a water pump with relatively suitable load is selected from a series of water pumps. However, the water pump industry has developed so far that its service and development objects are more for user water supply, large equipment water supply and chemical use, and the number of models specially developed for heat pumps is small. Therefore, in the design of the heat pump, it is inevitable to select a large load with poor energy efficiency. If the selection is small, the head and flow are insufficient, and the optimal solution cannot be achieved. In the operation of the unit, the fixed frequency water pump always operates at a rated / fixed frequency, and the energy efficiency is also poor. In the actual scene of the user, the opening and stopping of the fixed frequency water pump greatly changes the flow of the pipeline, generates water hammer sound of the water system, and affects the user experience. In the few manufacturers using variable frequency water pumps, the required flow is determined by real-time monitoring of the required refrigeration / heat to control the speed of the water pump. At this time, the head required by the system lacks calculation and matching. Moreover, the judgment of the minimum head and minimum flow is generally lacking, and the reliability, stability and energy efficiency of the unit need to be improved. SUMMARY

[0003] The present application aims to overcome the lack of judgment and matching of the head and minimum flow in the prior art, which leads to low stability and energy efficiency of the unit, and provides a variable frequency water pump self-adaptive adjustment control method for heat pump unit, which effectively solves the difficulty of real-time matching of the head and flow, and effectively improves the stability and energy efficiency of the unit.

[0004] To solve the above technical problems, the technical scheme adopted by the present application is:

[0005] A variable frequency water pump self-adaptive adjustment control method for heat pump unit is provided, comprising the following steps:

[0006] S1. Obtain the head-flow characteristic curve of the variable frequency water pump at each speed

[0007] S2. According to the number of user end equipment turned on, the variable frequency water pump is operated to increase and decrease the frequency, and the flow and head of the variable frequency water pump at each speed are recorded to fit the head-flow characteristic curve of the current pipeline;

[0008] S3. Determine the required water flow according to the number of user end devices, obtain the optimal working point under the current state and the rotating speed of the variable frequency water pump; wherein the working point is the intersection point of the head-flow characteristic curve of the pipeline and the head-flow characteristic curve of the variable frequency water pump;

[0009] S4. According to the flow feedback of each end, after obtaining the optimal working point under the current state, it is verified whether the current water flow of each end meets the rated flow of the end; if yes, the current rotating speed is executed; if no, frequency adjustment is performed until the requirement is met.

[0010] The variable frequency water pump adaptive adjustment control method of the heat pump unit according to the present application calculates the head-flow characteristic curve of the pipeline under each condition through the speed and frequency adjustment of the variable frequency water pump according to the different use conditions of the user end devices; the head requirement of the waterway is obtained through the head-flow characteristic curve of the pipeline, and the flow requirement is supplied according to the actual use condition of the user end devices, so that the flow change of the whole water system is small, the problem of water hammer is effectively solved, the stability of the system is improved, and the energy efficiency of the system is also improved; after the speed adjustment and stable operation, a detection stage is added, and the reliability of the water system is further ensured.

[0011] Preferably, in step S1, the head-flow characteristic curve of the variable frequency water pump under each rotating speed is obtained according to the data provided by the variable frequency water pump manufacturer or through testing; the real-time flow of the pipeline is monitored through the flow feedback function of the variable frequency water pump or by setting a flow meter at the outlet of the variable frequency water pump; the real-time head of the outlet of the variable frequency water pump is monitored by setting a pressure gauge at the outlet of the variable frequency water pump. The performance curve of the variable frequency water pump is generally the performance curve of the highest rotating speed specified in the specification book. According to the automatic speed adjustment of the system requirement, the characteristic curve is parallelly moved up (preferably not more than 6%) and down (preferably not more than 40%). The head-flow performance curve of the variable frequency water pump under each rotating speed can be obtained according to the manufacturer's data or testing.

[0012] The pipeline characteristic curve is equal to in numerical value, a is the pipeline resistance comprehensive coefficient, and Q is the pipeline water flow. However, since the pipeline conditions of each user are inconsistent, the length, pipe diameter and number of elbows and tees are inconsistent, so the accuracy of the coefficient a cannot be guaranteed. Further, the change of the end will cause the change of the pipeline characteristic curve, and the variable frequency of the water pump will also cause the change of the performance curve of the water pump, but after stabilization, the two will be in a balance. Therefore, in the present application, the intersection point of the head-flow characteristic curve of the pipeline and the head-flow performance curve of the variable frequency water pump is set as the working point of the waterway at this time.

[0013] Preferably, in step S2, the variable frequency water pump is started and the frequency is increased to make the real-time flow Q 实 of the unit reach the minimum flow Q min of the unit; if Q实 ±ΔQ=Q min , in the unit minimum flow stable operation preset time; if Q 实 ±ΔQ is greater than or less than Q min , after running the preset time, check again, if multiple checks do not meet, then stop troubleshooting; wherein, ΔQ is the set water flow fluctuation range value. After the equipment starts, first check whether the entire system can operate normally, to ensure the stability of subsequent frequency modulation, avoid affecting stability and accuracy due to system failure.

[0014] Preferably, in step S2, further comprising judging the speed regulation range of the variable frequency water pump of the current user, setting the speed regulation range of the variable frequency water pump as R1~Rn: if the minimum flow speed r min ≤R1, the speed regulation range of the variable frequency water pump of the current user is R1~Rn; if the minimum flow speed r min >R1, the speed regulation range of the variable frequency water pump of the current user is r min ~ Rn; the speed regulation range is divided into three speed intervals, the first speed interval is r min / R1~(R1+ΔR), the second speed interval is (R1+ΔR)~(R1+2ΔR), and the third speed interval is (R1+2ΔR)~Rn; wherein, ΔR=(Rn~R1) / 3. Assuming that the speed regulation range of the variable frequency water pump is 1800r~3200r; if the minimum flow speed r min ≤1800r, the speed regulation range of the variable frequency water pump of the current user is 1800r~3200r; if the minimum flow speed r min >1800r, the speed regulation range of the variable frequency water pump of the current user is r min ~3200r; the speed regulation range is divided into three speed intervals, the first speed interval is r min / 1800r~2300r, the second speed interval is 2300r~2800r, and the third speed interval is 2700r~3200r.

[0015] The application makes special protective measures for the minimum flow of the unit based on the frequency conversion range of the variable frequency water pump, and through the flow feedback / flow meter of the variable frequency water pump, the function of removing the water flow switch can be achieved, and the cost can be reduced and the quality can be improved.

[0016] Preferably, according to the rated capacity of the unit, the rated water flow is calculated, and 60% of the rated water flow of the unit is set as the minimum flow of the unit, and the frequency corresponding to the minimum flow is the minimum flow speed r min of the unit.

[0017] Preferably, the step S2 specifically comprises:

[0018] If the number of user terminal devices turned on is n=1, the variable frequency water pump speed is r min / R1, Nr increases every t seconds, and the flow rate and head are recorded at each speed; after running for a preset time, the head-flow characteristic curve of the current pipeline is fitted by the working point at each speed.

[0019] If the number of user terminal devices turned on is n=2, the speed of the variable frequency water pump increases from (R1+ΔR) to Nr every t seconds, and the flow rate and head at each speed are recorded; after running for a preset time, the head-flow characteristic curve of the current pipeline is fitted by the working point at each speed.

[0020] If the number of user terminal devices turned on is n=3, the speed of the variable frequency water pump increases from (R1+2ΔR) to Nr every t seconds, and the flow rate and head at each speed are recorded; after running for a preset time, the head-flow characteristic curve of the current pipeline is fitted by the working point at each speed.

[0021] Preferably, in step S2:

[0022] If the number of user-end devices activated is n=1, the maximum water flow rate Q1 detected by the variable frequency water pump within the current speed range is... max <Q 总 Q 总 If the total water flow required by the current water system is given, the variable frequency pump speed will be adjusted to the next speed range; if the detected minimum water flow value Q1 min >Q 总 Then, based on the minimum flow rate and rotational speed r min Run; when the detected water flow value Q1=Q 总 Based on the operating points of each speed within the specified speed range, the head-flow characteristic curve of the current pipeline is fitted again.

[0023] If the number of user-end devices activated is n=2, the maximum water flow rate Q2 detected by the variable frequency water pump within the current speed range is... max <Q 总 If the variable frequency pump speed is adjusted to the next speed range, then the minimum water flow rate Q2 will be adjusted accordingly. min >Q 总 The variable frequency pump speed will be adjusted to the next speed range; when the detected water flow value Q2=Q 总 Based on the operating points of each rotational speed in the range, the head-flow characteristic curve of the current pipeline is fitted again.

[0024] If the number of user terminal devices turned on is n=3, the maximum water flow value Q3 detected by the variable frequency water pump in the current speed range is... max <Q 总 If the minimum water flow rate Q3 is detected, then it will operate at the maximum speed;min >Q 总 , then the variable frequency water pump speed is adjusted to the next higher speed interval; when there is a detected water flow value Q3=Q 总 , according to the working point of each speed in the interval, the current pipeline head-flow characteristic curve is fitted again.

[0025] In the fitting of the pipeline head-flow characteristic curve stage, the partition speed-up and speed-down make the flow change of the whole water system small, effectively solving the water hammer sound and other problems, and increasing the system life.

[0026] Preferably, in step S3, the required water flow of each terminal is Q 末 When the user opens a terminal device, the system water flow is slightly greater than Q 末 , and Q 末 represents;

[0027] If the number of user terminal devices opened is n=1, Q 总 =Q 末 , the current pipeline pressure loss, i.e. the minimum head that the water pump needs to provide, is obtained through the current pipeline head-flow characteristic curve and the total water flow Q 总 required by the current water system, and the optimal speed of the water pump is obtained;

[0028] If the number of user terminal devices opened is n=2, Q 总 =2Q 末 , the current pipeline pressure loss, i.e. the minimum head that the water pump needs to provide, is obtained through the current pipeline head-flow characteristic curve and the total water flow Q 总 required by the current water system, and the optimal speed of the water pump is obtained;

[0029] If the number of user terminal devices opened is n=3, Q 总 =3Q 末 , the current pipeline pressure loss, i.e. the minimum head that the water pump needs to provide, is obtained through the current pipeline head-flow characteristic curve and the total water flow Q 总 required by the current water system, and the optimal speed of the water pump is obtained.

[0030] Preferably, in step S4, the flow Q 检 of the opened terminal device is detected, and it is verified whether the flow Q 检 of each opened terminal device meets the rated flow Q 末 of the terminal device; if Q 检 ≥Q 末 , then the current speed is run; if Q 检 <Q 末 , then the speed of the variable frequency water pump is increased until Q 检 ≥Q 末The application further ensures the reliability of the water system after the detection stage is added after the speed is stabilized.

[0031] The application also provides a heat pump unit variable frequency water pump adaptive regulation control system, which comprises a heat pump unit, a variable frequency water pump connected with the water inlet end of the heat pump unit, a plurality of terminal devices connected with the water outlet end of the heat pump unit and arranged in parallel, a water tank connected with the variable frequency water pump and the terminal devices, a detection unit arranged in a water circuit and used for detecting water flow or pipeline pressure, and a controller in communication connection with the variable frequency water pump and the detection unit, wherein the controller executes the variable frequency water pump adaptive regulation control method described above.

[0032] Compared with the prior art, the application has the beneficial effects that:

[0033] The application provides a heat pump unit variable frequency water pump adaptive regulation control method, which calculates the head-flow characteristic curve of a pipeline under each condition by adjusting the speed and frequency of the variable frequency water pump according to the different use conditions of user terminal devices, calculates the head demand of the water circuit through the head-flow characteristic curve of the pipeline, and supplies the flow demand according to the actual use conditions of the user terminal devices, so that the flow change of the entire water system is small, the problem of water hammer is effectively solved, the stability of the system is improved, and the energy efficiency of the system is improved. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a flowchart of the heat pump unit variable frequency water pump adaptive regulation control method.

[0035] Figure 2 It is a system structure schematic diagram in Example Three.

[0036] In the drawings: 10, heat pump unit; 20, variable frequency water pump; 30, terminal device; 40, water tank; 51, first pressure gauge; 52, flowmeter; 53, second pressure gauge. DETAILED DESCRIPTION

[0037] The application will be further described below in combination with the specific embodiments. The drawings are only used for exemplary description, and the representation is only a schematic diagram, not a physical diagram, and cannot be understood as a limitation on the patent; in order to better illustrate the embodiments of the application, some components in the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it can be understood that some well-known structures and their descriptions in the drawings may be omitted.

[0038] The same or similar reference numerals in the drawings of the embodiments of the present application correspond to the same or similar components; in the description of the present application, it is understood that if the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right" and the like are based on the orientations or positional relationships shown in the drawings, they are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationship in the drawings are only used for exemplary illustration, and cannot be understood as a limitation on the present patent, for those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0039] Embodiment one

[0040] The present embodiment is a first embodiment of a variable frequency water pump self-adaptive adjustment control method for a heat pump unit, as shown in Figure 1 , comprising the following steps:

[0041] S1. Obtain the head-flow characteristic curve of the variable frequency water pump under each rotating speed

[0042] S2. According to the number of user terminal equipment turned on, the variable frequency water pump performs frequency increasing and frequency decreasing operation, and records the flow and head of the variable frequency water pump under each rotating speed, and fits the head-flow characteristic curve of the current pipeline;

[0043] S3. Determine the required water flow according to the number of user terminal equipment turned on, obtain the best working point under the current state and the rotating speed of the variable frequency water pump; wherein the working point is the intersection point of the head-flow characteristic curve of the pipeline and the head-flow characteristic curve of the variable frequency water pump.

[0044] S4. According to the flow feedback of each terminal, after obtaining the best working point under the current state, it is verified whether the current water flow of each terminal meets the rated flow of the terminal; if it meets, it is executed according to the current rotating speed, if it does not meet, it is adjusted in frequency until it meets.

[0045] In step S1, the head-flow characteristic curve of the variable frequency water pump under each rotating speed is obtained according to the data provided by the variable frequency water pump manufacturer or by testing; the real-time flow of the pipeline is monitored through the flow feedback function of the variable frequency water pump or by setting a flow meter at the outlet of the variable frequency water pump; the real-time head of the outlet of the variable frequency water pump is monitored by setting a pressure gauge at the outlet of the variable frequency water pump. The performance curve of the variable frequency water pump is generally the performance curve of the highest rotating speed specified in the specification, which is automatically adjusted according to the system requirements, at this time the characteristic curve is parallelly moved up (preferably not more than 6%) and down (preferably not more than 40%), which can be obtained according to the manufacturer's data or testing the head-flow performance curve of the variable frequency water pump under each rotating speed.

[0046] The pipeline characteristic curve is equal to , a is the pipeline resistance comprehensive coefficient, Q is the pipeline water flow, but since the pipeline conditions of each user are inconsistent, the length, pipe diameter and the number of elbows and tees are inconsistent, so the accuracy of the coefficient a cannot be guaranteed; further, the change of the end will cause the change of the pipeline characteristic curve, and the variable frequency of the water pump will also cause the change of the performance curve of the water pump, but after stabilization, the two will be in a balance. Therefore, in the present application, the intersection point of the head-flow characteristic curve of the pipeline and the head-flow performance curve of the variable frequency water pump is set as the working point of the waterway at this time.

[0047] In the present embodiment, according to the rated capacity of the unit, the rated water flow is calculated, and 60% of the rated water flow of the unit is set as the minimum flow of the unit, and the frequency corresponding to the minimum flow is the minimum flow speed r min .

[0048] In step S2, the variable frequency water pump is started, the frequency is increased, the real-time flow Q 实 of the unit reaches the minimum flow Q min of the unit; if Q 实 ±ΔQ=Q min , the minimum flow of the unit is stably operated for a preset time; if Q 实 ±ΔQ is greater than or less than Q min , after the preset time of operation, it is checked again, and if it does not meet the multiple checks, it is stopped to troubleshoot the fault; wherein ΔQ is the set water flow allowable fluctuation range value. After the equipment is started, it is checked whether the entire system can operate normally to ensure the stability of the subsequent frequency regulation, and to avoid affecting the stability and accuracy due to system failure.

[0049] In step S2, it also includes judging the speed regulation range of the variable frequency water pump of the current user, and setting the speed regulation range of the variable frequency water pump as R1~Rn: if the minimum flow speed r min ≤R1, the speed regulation range of the variable frequency water pump of the current user is R1~Rn; if the minimum flow speed r min >R1, the speed regulation range of the variable frequency water pump of the current user is r min ~ Rn; the speed regulation range is divided into three speed intervals, the first speed interval is r min / R1~(R1+ΔR), the second speed interval is (R1+ΔR)~(R1+2ΔR), and the third speed interval is (R1+2ΔR)~Rn; wherein ΔR=(Rn~R1) / 3.

[0050] The present application is based on the frequency conversion range of the variable frequency water pump, and special protection measures are taken for the minimum flow of the unit, and through the flow feedback / flow meter of the variable frequency water pump, the function of removing the water flow switch can be achieved, and the cost can be reduced and the quality can be improved.

[0051] Step S2 specifically includes:

[0052] If the number of user end devices opened n = 1, the variable frequency water pump speed is r min / R1, increase Nr every t seconds, and record the flow and head at each speed; After running for a preset time, the head-flow characteristic curve of the current pipeline is fitted through the working points at each speed.

[0053] If the number of user end devices opened n = 2, the variable frequency water pump speed is (R1+ΔR), increase Nr every t seconds, and record the flow and head at each speed; After running for a preset time, the head-flow characteristic curve of the current pipeline is fitted through the working points at each speed.

[0054] If the number of user end devices opened n = 3, the variable frequency water pump speed is (R1+2ΔR), increase Nr every t seconds, and record the flow and head at each speed; After running for a preset time, the head-flow characteristic curve of the current pipeline is fitted through the working points at each speed.

[0055] In addition, in step S2:

[0056] If the number of user end devices opened n = 1, the maximum water flow value Q1 max detected by the variable frequency water pump in the current speed range is less than Q 总 , and the total water flow required by the current water system is Q 总 , the variable frequency water pump speed is adjusted to the next speed range; if the minimum water flow value Q1 min detected is greater than Q 总 , the variable frequency water pump runs at the minimum flow speed r min ; when there is a detected water flow value Q1=Q 总 , the head-flow characteristic curve of the current pipeline is fitted again according to the working points of each speed in the speed range;

[0057] If the number of user end devices opened n = 2, the maximum water flow value Q2 max detected by the variable frequency water pump in the current speed range is less than Q 总 , the variable frequency water pump speed is adjusted to the next speed range; if the minimum water flow value Q2 min detected is greater than Q 总 , the variable frequency water pump speed is adjusted to the previous speed range; when there is a detected water flow value Q2=Q 总 , the head-flow characteristic curve of the current pipeline is fitted again according to the working points of each speed in the speed range;

[0058] If the number of user end devices opened n = 3, the maximum water flow value Q3 max detected by the variable frequency water pump in the current speed range is less than Q 总, then run at the maximum speed; if the detected minimum water flow value Q3 min > Q 总 , then the frequency conversion water pump speed is adjusted to the next higher speed interval; when there is a detected water flow value Q3=Q 总 , according to the working point of each speed in the interval, the current pipeline head-flow characteristic curve is fitted again.

[0059] When there is a detected water flow value Q1=Q 总 , Q2=Q 总 , and Q3=Q 总 , it indicates that there is an optimal water flow working point in the interval, so the speed of the interval is finely adjusted, and a more accurate pipeline head-flow characteristic curve is fitted.

[0060] In the fitting of the pipeline head-flow characteristic curve stage, the speed is increased and decreased by zoning, so that the flow of the entire water system changes little, effectively solving the problem of water hammer sound and increasing the service life of the system.

[0061] In step S3, the required water flow of each terminal is Q 末 When the user turns on a terminal device, the system water flow is slightly greater than Q 末 , which is represented by Q' 末 .

[0062] If the number of user terminal devices turned on is n=1, Q 总 =Q' 末 , the pressure loss of the current pipeline, i.e. the minimum head that the water pump needs to provide, is obtained through the head-flow characteristic curve of the current pipeline and the total water flow Q 总 required by the current water system, and the optimal speed of the water pump is obtained.

[0063] If the number of user terminal devices turned on is n=2, Q 总 =2Q' 末 , the pressure loss of the current pipeline, i.e. the minimum head that the water pump needs to provide, is obtained through the head-flow characteristic curve of the current pipeline and the total water flow Q 总 required by the current water system, and the optimal speed of the water pump is obtained.

[0064] If the number of user terminal devices turned on is n=3, Q 总 =3Q' 末 , the pressure loss of the current pipeline, i.e. the minimum head that the water pump needs to provide, is obtained through the head-flow characteristic curve of the current pipeline and the total water flow Q 总 required by the current water system, and the optimal speed of the water pump is obtained.

[0065] In step S4, the flow Q 检, check the flow Q of each opened terminal device 检 whether the rated flow Q of the terminal device is met 末 , if Q 检 ≥ Q 末 , run at the current speed; if Q 检 < Q 末 , increase the speed of the variable frequency water pump until Q 检 ≥ Q 末 . The present application further ensures the reliability of the water system by adding a detection stage after speed stabilization.

[0066] The self-adaptive adjustment control method for the variable frequency water pump of the heat pump unit provided in the embodiment calculates the head-flow characteristic curve of the pipeline under each condition by speed and frequency adjustment of the variable frequency water pump according to different use conditions of the user terminal device; calculates the head demand of the waterway through the head-flow characteristic curve of the pipeline, and supplies the flow demand according to the actual use condition of the user terminal device, so that the flow change of the entire water system is small, effectively solves the problem of water hammer, improves the stability of the system, and also improves the energy efficiency of the system; after speed stabilization, a detection stage is added to further ensure the reliability of the water system.

[0067] Embodiment Two

[0068] The second embodiment of the self-adaptive adjustment control method for the variable frequency water pump of the heat pump unit includes the following steps:

[0069] Step 1: in the heating mode, the unit runs, and the variable frequency water pump starts.

[0070] Step 2: the variable frequency water pump starts, and the frequency is slowly increased for 1 min to detect the real-time flow Q of the unit, and after 1 min, the real-time flow of the unit reaches the minimum flow r min of the unit, and at this time, the speed is the minimum flow speed r min of the unit:

[0071] If the real-time flow Q of the unit = Q min (±0.1 m^3 / h), the unit is stably run for 15 s on the minimum flow platform

[0072] If the real-time flow Q of the unit > or < Q min (±0.1 m^3 / h), it is detected again after 15 s; if the condition is not met for three times, it is reported that the water flow switch is faulty, and the machine is stopped to troubleshoot the fault.

[0073] Step 3: the unit is stably run for 15 s on the minimum flow platform.

[0074] Step 4: judge the speed adjustment range of the current water pump, in this embodiment, the frequency adjustment range of the variable frequency water pump is 1800 r~3200 r:

[0075] If the minimum flow rate rotation speed r min ≤1800r, the water pump rotation speed adjustment range of the current user is 1800r-3200r

[0076] If the minimum flow rate rotation speed r min >1800r, the water pump rotation speed adjustment range of the current user is r min -3200r

[0077] Further, the rotation speed adjustment range is divided into three intervals: the first rotation speed interval is r min / 1800r-2300r, the second rotation speed interval is 2300r-2800r, and the third rotation speed interval is 2700r-3200r.

[0078] Step 5: Detect the number of user terminal equipment openings:

[0079] (1) If the number of user terminal equipment openings n=1, the variable frequency water pump rotation speed is r min / 1800r, and the flow rate and head at each rotation speed are recorded every 10s. After 1min, the head-flow rate characteristic curve of the pipeline is fitted through the working points at each rotation speed.

[0080] If the detected flow rate value Q1 max <Q 总 at each rotation speed in the interval, the water pump rotation speed is adjusted to the next interval;

[0081] If Q1 min >Q 总 , the variable frequency water pump is operated at the minimum flow rate rotation speed, indicating that the variable frequency water pump is oversized;

[0082] When Q1=Q 总 exists, the pipeline characteristic curve is fitted again according to the working points at each rotation speed in the interval.

[0083] (2) If n=2, the variable frequency water pump rotation speed is 2300r, and the flow rate and head at each rotation speed are recorded every 10s. After 1min, the head-flow rate characteristic curve of the pipeline is fitted through the working points at each rotation speed.

[0084] If the detected flow rate value Q2 max <Q 总 at each rotation speed in the interval, the water pump rotation speed is adjusted to the next interval;

[0085] If the detected flow rate value Q2 min >Q 总 at each rotation speed in the interval, the water pump rotation speed is adjusted to the next interval;

[0086] When Q2=Q总 According to the working points of each rotating speed in the interval, the head-flow characteristic curve of the pipeline is fitted again.

[0087] (3) If n=3, the rotating speed of the frequency conversion water pump is increased by 100r per 10s from 2700r, and the flow and head at each rotating speed are recorded. After 1min, the head-flow characteristic curve of the pipeline is fitted through the working points of each rotating speed.

[0088] If the detected flow value Q3 max <Q 总 at each rotating speed in the interval, the water pump is operated at the maximum rotating speed, indicating that the frequency conversion water pump is too small.

[0089] If the detected flow value Q3 min >Q 总 at each rotating speed in the interval, the rotating speed of the water pump is adjusted to the next interval;

[0090] If Q3=Q 总 exists, the head-flow characteristic curve of the pipeline is fitted again according to the working points of each rotating speed in the interval.

[0091] Step 6: Determine the total water flow required by the current water system through the number of open terminals:

[0092] Q 总 =nQ’ 末 The rated water flow required by each terminal is Q 末 When a user opens a terminal device, the system water flow is slightly greater than Q 末 , which is represented by Q’ 末 .

[0093] If the number of open user terminal devices n=1, Q 总 =Q’ 末 , the pressure loss of the current pipeline, i.e. the minimum head required by the water pump, is obtained through the head-flow characteristic curve of the current pipeline and the total water flow required by the current water system Q 总 , and the optimal rotating speed of the water pump is obtained.

[0094] If the number of open user terminal devices n=2, Q 总 =2Q’ 末 , the pressure loss of the current pipeline, i.e. the minimum head required by the water pump, is obtained through the head-flow characteristic curve of the current pipeline and the total water flow required by the current water system Q 总 , and the optimal rotating speed of the water pump is obtained.

[0095] If the number of open user terminal devices n=3, Q 总 =3Q’ 末 , the pressure loss of the current pipeline, i.e. the minimum head required by the water pump, is obtained through the head-flow characteristic curve of the current pipeline and the total water flow required by the current water system Q总 This gives us the pressure loss in the current pipeline, which is the minimum head the pump needs to provide, and thus the optimal pump speed.

[0096] Step 7: Detect the flow feedback Q of the enabled endpoint. 检 Check the water flow rate Q before each activated terminal. 检 Does it meet the rated flow rate Q at the terminal? 末 :

[0097] If Q 检 ≥Q 末 The rotational speed remains unchanged.

[0098] If Q 检 <Q 末 Increase the pump speed until Q 检 ≥Q 末 .

[0099] Example 3

[0100] This embodiment is an example of an adaptive adjustment and control system for a heat pump unit 10 and a variable frequency water pump 20. Figure 2 As shown, in this embodiment, the system includes a heat pump unit 10, a variable frequency water pump 20 connected to the water inlet of the heat pump unit 10, a plurality of terminal devices 30 connected to the water outlet of the heat pump unit 10 and arranged in parallel, a water tank 40 connecting the variable frequency water pump 20 and the terminal devices 30, a detection unit installed in the water circuit for detecting water flow or pipeline pressure, and a controller communicatively connected to the variable frequency water pump 20 and the detection unit. The controller executes the adaptive adjustment control method of the variable frequency water pump 20 described in Embodiment 1 or Embodiment 2.

[0101] The inspection unit includes a first pressure gauge 51 and a flow meter 52 installed on the main pipeline, and a second pressure gauge 53 installed on the outlet pipeline of each terminal device 30.

[0102] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0103] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for adaptive adjustment and control of a variable frequency water pump of a heat pump unit, characterized in that, The heat pump unit, the variable frequency water pump connected with the water inlet end of the heat pump unit, the several terminal devices connected with the water outlet end of the heat pump unit and arranged in parallel, the water tank connected with the variable frequency water pump and the terminal devices, the detection unit arranged in the water circuit for detecting the water flow or the pipeline pressure, and the controller in communication connection with the variable frequency water pump and the detection unit; The method comprises the following steps: S1. Obtain the head-flow characteristic curve of the variable frequency water pump at each rotating speed; S2. According to the number of user terminal devices turned on, the variable frequency water pump performs frequency increasing and frequency decreasing operations, and records the flow and head of the variable frequency water pump at each rotating speed, and fits the head-flow characteristic curve of the current pipeline; S3. According to the number of user terminal devices turned on, determine the required water flow, obtain the optimal working point in the current state and the rotating speed of the variable frequency water pump; wherein the working point is the intersection point of the head-flow characteristic curve of the pipeline and the head-flow characteristic curve of the variable frequency water pump; S4. According to the flow feedback of each terminal, after obtaining the optimal working point in the current state, check whether the current water flow of each terminal meets the rated flow of the terminal; if yes, execute according to the current rotating speed, if not, perform frequency adjustment until the requirement is met. Wherein, in step S2, the variable frequency water pump is started, the frequency increasing operation is performed, the real-time flow Q of the unit is obtained 实 to reach the minimum flow Q of the unit min ; if Q 实 ± ΔQ = Q min , the unit is stably operated for a preset time; if Q 实 ± ΔQ is greater than or less than Q min , after the preset time of operation, the checking is performed again, and if the checking does not meet the requirement for multiple times, the unit is stopped to check the fault; wherein, ΔQ is a set water flow fluctuation range value; In step S2, the rotational speed adjustment range of the variable frequency water pump of the current user is also determined, and the rotational speed adjustment range of the variable frequency water pump is R1~Rn: if the minimum flow rotational speed r min ≤R1, the rotational speed adjustment range of the variable frequency water pump of the current user is R1~Rn; if the minimum flow rotational speed r min >R1, the rotational speed adjustment range of the variable frequency water pump of the current user is r min ~Rn; the rotational speed adjustment range is divided into three rotational speed intervals, the first rotational speed interval is r min / R1~(R1+ΔR), the second rotational speed interval is (R1+ΔR)~(R1+2ΔR), and the third rotational speed interval is (R1+2ΔR)~Rn; wherein ΔR=(Rn~R1) / 3.

2. The method for adaptive adjustment and control of variable frequency water pump of heat pump unit according to claim 1, characterized in that, In step S1, the head-flow characteristic curve of the variable frequency water pump at each rotating speed is obtained according to the data provided by the variable frequency water pump manufacturer or through testing; the real-time flow of the pipeline is monitored through the flow feedback function of the variable frequency water pump or by setting a flow meter at the outlet of the variable frequency water pump; the real-time head of the outlet of the variable frequency water pump is monitored by setting a pressure gauge at the outlet of the variable frequency water pump.

3. The method for adaptive adjustment and control of variable frequency water pump of heat pump unit according to claim 1, characterized in that, According to the rated capacity of the unit, the rated water flow is calculated, and 60% of the rated water flow of the unit is set as the minimum flow of the unit. The frequency corresponding to the minimum flow is the minimum flow speed r of the unit min .

4. The method for adaptive adjustment and control of variable frequency water pump for heat pump unit according to claim 1, characterized in that, The step S2 specifically comprises: If the number of user end devices n = 1, the frequency conversion water pump speed is r min / R1, each t seconds rise Nr, and record the flow, head under each speed; after running for a preset time, the head-flow characteristic curve of the current pipeline is fitted through the working points under each speed; If the number of user terminal devices turned on n=2, the rotating speed of the variable frequency water pump is (R1+ΔR), which increases Nr every t seconds, and the flow and head at each rotating speed are recorded; after running for a preset time, the head-flow characteristic curve of the current pipeline is fitted through the working points at each rotating speed; If the number of user terminal devices turned on n=3, the rotating speed of the variable frequency water pump is (R1+2ΔR), which increases Nr every t seconds, and the flow and head at each rotating speed are recorded; after running for a preset time, the head-flow characteristic curve of the current pipeline is fitted through the working points at each rotating speed.

5. The method for adaptive adjustment and control of variable frequency water pump of heat pump unit according to claim 4, characterized in that, In step S2: If the number of user-end devices activated is n=1, the maximum water flow rate Q1 detected by the variable frequency water pump within the current speed range is... max <Q 总 Q 总 If the total water flow required by the current water system is given, the variable frequency pump speed will be adjusted to the next speed range; if the detected minimum water flow value Q1 min >Q 总 Then, based on the minimum flow rate and rotational speed r min Run; when the detected water flow value Q1=Q 总 Based on the operating points of each speed within the specified speed range, the head-flow characteristic curve of the current pipeline is fitted again. If the number of user end devices n = 2, the maximum water flow value Q2 detected by the variable frequency water pump in the current speed interval max <Q 总 , the variable frequency water pump speed is adjusted to the next speed interval; if the minimum water flow value Q2 detected is greater than Q min >Q 总 , the variable frequency water pump speed is adjusted to the previous speed interval; when the water flow value Q2 = Q is detected 总 , according to the working point of each speed in the interval, the current pipeline head-flow characteristic curve is fitted again; If the number of user end devices n = 3, the maximum water flow value Q3 detected by the variable frequency water pump in the current speed interval max <Q 总 , then run at the maximum speed; if the minimum water flow value Q3 detected by the variable frequency water pump min >Q 总 , then the variable frequency water pump speed is adjusted to the next speed interval; when there is a water flow value Q3 = Q 总 , according to the working point of each speed in the interval, the head-flow characteristic curve of the current pipeline is fitted again.

6. The method for adaptive adjustment and control of variable frequency water pump for heat pump unit according to claim 5, characterized in that, In step S3, the required water flow rate for each end device is Q 末 When the user turns on an end device, the system water flow rate is slightly greater than Q 末 , expressed as Q' 末 ; If the number of user end devices is n = 1, Q 总 = Q' 末 , through the current pipeline head-flow characteristic curve and the total water flow Q 总 required by the current water system, the pressure loss of the current pipeline, i.e. the minimum head that the water pump needs to provide, is obtained, and the optimal speed of the water pump is obtained. If the number of user end devices is n = 2, Q 总 = 2Q' 末 , the pressure loss of the current pipeline, i.e. the minimum head that the water pump needs to provide, is obtained through the head-flow characteristic curve of the current pipeline and the total water flow Q 总 required by the current water system, and the optimal rotating speed of the water pump is obtained. If the number of user end devices is n=3, Q 总 =3Q' 末 , through the current pipeline head-flow characteristic curve and the total water flow Q 总 required by the current water system, the pressure loss of the current pipeline is obtained, that is, the minimum head that the water pump needs to provide, and the optimal speed of the water pump is obtained.

7. The method for adaptive adjustment and control of variable frequency water pump of heat pump unit according to claim 6, characterized in that, In step S4, the flow Q of the opened end device is detected 检 The flow Q of each opened end device is checked 检 Whether the rated flow Q of the end device is met 末 If Q 检 ≥ Q 末 , it is run at the current speed; if Q 检 < Q 末 , the speed of the variable frequency water pump is increased until Q 检 ≥ Q 末 .

8. A variable frequency water pump self-adaptive adjustment control system for a heat pump unit, comprising a heat pump unit, a variable frequency water pump connected to a water inlet end of the heat pump unit, a plurality of terminal devices connected to a water outlet end of the heat pump unit and arranged in parallel, a water tank connected between the variable frequency water pump and the terminal devices, a detection unit arranged in a water circuit and used for detecting water flow or pipeline pressure, and a controller in communication connection with the variable frequency water pump and the detection unit. The controller executes the variable frequency water pump adaptive adjustment control method of any one of claims 1 to 7.

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