A method for intelligent energy-saving debugging and energy efficiency optimization of a heat pump unit

Abstract

This invention discloses an intelligent energy-saving commissioning and energy efficiency optimization method for heat pump units, relating to the field of heat pump unit control technology. The method includes collecting unit operating parameters and determining the initial electronic expansion valve step count for this round of commissioning; at the initial electronic expansion valve step count, generating baseline performance values ​​based on water-side parameters and overall unit power, and generating directional judgment benchmark values ​​based on compressor drive branch parameters and suction / discharge parameters; when each adjustment direction satisfies the safety boundary and the corresponding target step count is within the allowable step count range of the electronic expansion valve, performing a short-term step adjustment in the corresponding direction, generating a directional judgment value for the corresponding direction, and determining candidate valve positions. This invention reduces the number of repeated trials, improves unit operating stability, and enhances the overall water-side energy efficiency level.

Description

Technical Field

[0001] This invention relates to the field of heat pump unit control technology, and in particular to a method for intelligent energy-saving commissioning and energy efficiency optimization of heat pump units. Background Technology

[0002] Heat pump units, due to their high energy efficiency and good electrification adaptability, have been widely used in building heating, domestic hot water, and industrial waste heat recovery. With the development of variable frequency compressors, electronic expansion valves, and multi-sensor control technology, the operation control of heat pump units has gradually shifted from early fixed parameter control to dynamic adjustment based on changes in operating conditions. As a key actuator affecting refrigerant flow distribution, evaporator liquid supply status, compressor suction and discharge status, and overall unit energy efficiency, the electronic expansion valve is usually adjusted through suction superheat, discharge temperature, pressure parameters, or empirical control tables. Some solutions also combine variable frequency operation status for linkage control to improve the unit's operational stability and energy efficiency under different loads and environmental conditions.

[0003] However, most existing electronic expansion valve regulation technologies still rely on closed-loop control of a single thermodynamic parameter or preset empirical value correction. The control objectives focus on preventing liquid slugging, preventing high temperature, or maintaining basic stable operation. They do not make sufficient use of the matching relationship between the actual heat exchange effect on the water side and the input power of the whole machine, making it difficult to simultaneously take into account safety, energy saving and regulation efficiency under complex operating conditions. Summary of the Invention

[0004] This invention provides a method for intelligent energy-saving commissioning and energy efficiency optimization of heat pump units, comprising the following steps:

[0005] Collect unit operating parameters to determine the starting number of electronic expansion valve steps for this round of commissioning;

[0006] At the initial electronic expansion valve step number, a baseline performance value is generated based on water-side parameters and overall machine power, and a direction determination benchmark value is generated based on compressor drive branch parameters and intake and exhaust parameters.

[0007] When the safety boundary is met in each adjustment direction and the corresponding target number of steps is within the allowable number of steps of the electronic expansion valve, a short-term step adjustment is performed in the corresponding direction to generate a direction determination value for the corresponding direction and determine the candidate valve position.

[0008] When the candidate valve position is different from the starting electronic expansion valve step number, a short-term pre-evaluation is first performed based on the compressor drive branch parameters and suction and discharge parameters. If the pre-evaluation fails, the process returns to the starting electronic expansion valve step number, and the starting electronic expansion valve step number is determined as the final execution step number, and the baseline performance value is determined as the final confirmation value. After the pre-evaluation passes, a long-term confirmation is performed based on the water-side parameters and the overall power to obtain the candidate performance value.

[0009] Based on the comparison results between the candidate performance values ​​and the baseline performance values, the final number of execution steps and the final confirmation value are determined, and the final number of execution steps, the final confirmation value, and the corresponding operating conditions are updated to the operating condition record library.

[0010] Preferably, the water-side parameters include water flow rate, supply water temperature, and return water temperature; the compressor drive branch parameters and suction / discharge parameters include compressor drive branch voltage, compressor drive branch current, compressor speed, suction pressure, discharge pressure, suction temperature, and discharge temperature; the total power is the total active power; and the safety boundaries include the upper limit of discharge temperature, the lower limit of suction superheat, the lower limit of suction pressure, the upper limit of discharge pressure, the minimum allowable number of steps of the electronic expansion valve, and the maximum allowable number of steps of the electronic expansion valve.

[0011] Preferably, determining the starting electronic expansion valve step number for this round of debugging includes:

[0012] When the unit meets the requirements of continuous and stable operation, is not in defrosting state, has no fault codes, and has not experienced mode switching or shutdown and restart within a preset time, query the operating condition record database.

[0013] When there are matching records with the same operating mode and whose current average outdoor temperature, current average compressor speed, and current average suction pressure fall into the corresponding intervals, the nearest neighbor matching is performed in sequence according to the difference in outdoor temperature, the difference in compressor speed, and the difference in suction pressure. The number of steps corresponding to the matching record is determined as the starting number of electronic expansion valve steps.

[0014] If no matching record exists, maintain the current actual step count as the starting electronic expansion valve step count.

[0015] Preferably, the generation of baseline performance values ​​includes:

[0016] The water-side parameters and total power of the unit are collected within a baseline window at the initial electronic expansion valve step number. The ratio of the average water-side heating capacity to the average total active power of the unit within the baseline window is calculated as the baseline performance value.

[0017] The generation direction determination benchmark value includes:

[0018] At the initial electronic expansion valve step, the compressor drive branch parameters and intake and exhaust parameters are collected within a baseline short window. The ratio of theoretical compression work per revolution to electrical input work per revolution within the short window is calculated and used as the reference value for direction determination.

[0019] Preferably, the short-term step adjustment includes:

[0020] When the opening direction meets the safety boundary and the target step number corresponding to the opening direction is not greater than the maximum allowable step number of the electronic expansion valve, a short-term step number adjustment is performed along the opening direction based on the initial electronic expansion valve step number and a positive direction judgment value is generated.

[0021] After restoring the electronic expansion valve to the initial electronic expansion valve step number and completing the restoration judgment, when the safety boundary is met in the closing direction and the target step number corresponding to the closing direction is not less than the minimum allowable step number of the electronic expansion valve, a short-term step number adjustment is performed along the closing direction and a reverse direction judgment value is generated.

[0022] The recovery determination is based on the rate of change of the inhalation pressure, exhaust pressure, inhalation temperature, and exhaust temperature.

[0023] Preferably, determining the candidate valve position and performing a short-term pre-evaluation includes:

[0024] When a positive direction judgment value has been generated and is higher than the direction judgment reference value, and a negative direction judgment value has not been generated or the positive direction judgment value is not lower than the negative direction judgment value, the number of steps corresponding to the opening direction is determined as the candidate valve position.

[0025] When the reverse direction judgment value has been generated and is higher than the direction judgment reference value, and the forward direction judgment value has not been generated or the reverse direction judgment value is higher than the forward direction judgment value, the number of steps corresponding to the closing direction is determined as the candidate valve position.

[0026] When none of the generated direction determination values ​​are better than the direction determination reference value, or when neither the opening direction nor the closing direction has been adjusted in a short time step, the initial electronic expansion valve step number is determined as the final execution step number, and the baseline performance value is determined as the final confirmation value.

[0027] When the candidate valve position is different from the initial electronic expansion valve step number, the electronic expansion valve is first controlled to reach the candidate valve position, and then a short-term pre-evaluation is performed based on the compressor drive branch parameters and suction and discharge parameters.

[0028] If the short-term pre-assessment fails, the monitoring parameters trigger the safety boundary, or the electronic expansion valve fails to remain in the candidate valve position, the electronic expansion valve is returned to the initial electronic expansion valve step number, and the initial electronic expansion valve step number is determined as the final execution step number, and the baseline performance value is determined as the final confirmation value.

[0029] Preferably, the long-term confirmation includes:

[0030] Under the candidate valve position, collect the water-side parameters and total power within a candidate long window, and calculate the ratio of the average water-side heating capacity to the average total active power of the candidate long window as the candidate performance value.

[0031] When the candidate performance value is higher than the baseline performance value, the candidate valve position is determined as the final execution step, and the candidate performance value is determined as the final confirmation value.

[0032] When the candidate performance value is not higher than the baseline performance value, or when a safety boundary is triggered during the candidate long window, the starting electronic expansion valve step number is determined as the final execution step number, and the baseline performance value is determined as the final confirmation value.

[0033] Preferably, the update to the operating condition record database includes:

[0034] The operating mode, outdoor temperature range, compressor speed range, and suction pressure range are used as operating conditions, and the corresponding center value, final number of execution steps, final confirmation value, and record quality flag are written into the operating condition record library.

[0035] If there is no record matching the current operating condition in the operating condition record database, a new record is appended and written.

[0036] When a matching record exists in the operating condition record library, the nearest neighbor match is performed in sequence according to the difference in the center value of outdoor temperature, the difference in the center value of compressor speed, and the difference in the center value of suction pressure to determine the target matching record. The record quality flag is compared first, and when the record quality flags are the same, the record corresponding to the one with the higher final confirmed value is retained.

[0037] The beneficial effects of this invention are as follows:

[0038] This invention, through a collaborative debugging mechanism, combined with bidirectional short-term testing of the electronic expansion valve, pre-evaluation of candidate valve positions, long-term confirmation, and retrieval and updating of the operating condition record library, solves the problems of single adjustment basis, reliance on experience for the initial valve position, delayed judgment of optimization direction, numerous invalid tests, and insufficient utilization of historical operating results in the existing technology of electronic expansion valves. Under the premise of meeting safety boundaries, it improves the accuracy of valve position adjustment, shortens the convergence time of the optimal step, reduces the number of repeated tests, and enhances the unit's operational stability and the overall energy efficiency level on the water side. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a block diagram of the intelligent energy-saving commissioning and energy efficiency optimization system for the heat pump unit in the embodiment;

[0041] Figure 2This is a flowchart of the intelligent energy-saving commissioning and energy efficiency optimization method for heat pump units in the embodiment. Detailed Implementation

[0042] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. This embodiment takes the online commissioning process of the electronic expansion valve of the heat pump unit in water-side heating mode as an example. Unless otherwise specified in the embodiment, the controller, sensor, driver, frequency converter, whole unit active power meter and electronic expansion valve are all conventional configurations of heat pump units.

[0043] Example

[0044] refer to Figure 1 and Figure 2 This embodiment provides a method for intelligent energy-saving commissioning and energy efficiency optimization of a heat pump unit. The method is executed by the unit controller, and the commissioning object is the electronic expansion valve. The controller is communicatively connected to the compressor inverter, suction pressure sensor, discharge pressure sensor, suction temperature sensor, discharge temperature sensor, outdoor temperature sensor, water-side flow meter, water-side supply water temperature sensor, water-side return water temperature sensor, whole unit active power meter, and electronic expansion valve driver. The controller can read the compressor drive branch voltage, compressor drive branch current, compressor speed, and actual step feedback of the electronic expansion valve, and can send target step command to the electronic expansion valve driver. The controller has a pre-stored working fluid thermophysical property database, which includes at least the correspondence between suction pressure, suction temperature and suction enthalpy, suction entropy, suction specific volume and corresponding saturation temperature, as well as the correspondence between discharge pressure, suction entropy and isentropic discharge enthalpy.

[0045] When the controller calls up thermophysical data, it first locates the adjacent node where the current operating condition is located, and then performs linear interpolation or bilinear interpolation to obtain the required thermophysical parameters under the current operating condition. When the intake pressure, intake temperature or exhaust pressure exceeds the coverage range of the thermophysical database, the controller terminates the current round of debugging and keeps the current actual number of steps of the electronic expansion valve unchanged.

[0046] To ensure that the thresholds, step sizes, window lengths, and criteria used in the online commissioning process have clear sources, this embodiment performs basic calibration before the unit is put into operation for the first time. The basic calibration is carried out under representative heating conditions.

[0047] The controller first reads the allowable outdoor temperature range and the compressor's rated maximum speed given by the compressor manufacturer for heating conditions. It then divides the allowable outdoor temperature range into five equal intervals and takes the midpoint of each interval as five representative outdoor temperatures. Next, it sets the compressor target speed to 30%, 60%, and 90% of the rated maximum speed, respectively, as three representative compressor target speeds. Subsequently, it combines the five representative outdoor temperatures with the three representative compressor target speeds to form fifteen representative operating conditions. Each representative operating condition is tested three times to form forty-five calibration samples.

[0048] During the sensor calibration phase, the controller fixes the electronic expansion valve at the intermediate step and continuously collects the intake pressure, exhaust pressure, intake temperature, exhaust temperature, water-side flow rate, supply water temperature, return water temperature and total active power for 600 seconds under each representative working condition. At the same time, it uses calibrated standard instruments to synchronously read the corresponding physical quantities.

[0049] The controller calculates the average deviation of each sensor over 600 seconds as a percentage of its range. When the average deviation of any sensor exceeds one percent of its range, zero-point correction or range correction is performed on that sensor, and 600 seconds of data are collected again until the average deviation does not exceed one percent of the range. The corrected coefficient is then written into the controller's non-volatile memory.

[0050] During the data preprocessing parameter determination stage, the controller constructs single-point glitch, double-point glitch, and step disturbance samples for stable data segments of intake pressure, exhaust pressure, intake temperature, exhaust temperature, water-side flow rate, supply water temperature, return water temperature, and total active power, and tests multiple combinations of median filtering and moving average.

[0051] Evaluation metrics include whether the residual deviation after glitch suppression is lower than the corresponding steady-state standard deviation, and whether the response delay to a real step disturbance is less than one second. The controller selects a set of parameters that simultaneously meets the above conditions and has the smallest total window length as online data preprocessing parameters.

[0052] In this embodiment, a preprocessing method is adopted, which first performs five-point median filtering and then ten-point moving average. The sampling period is 0.1 seconds. During online execution, if any sensor has no valid data for two consecutive seconds, or if the filtered data exceeds the corresponding physical range, the data segment is recorded as invalid data. When this situation occurs during the debugging process, the controller terminates the current round of debugging.

[0053] During the safety boundary threshold calibration phase, the upper limit of exhaust temperature, the lower limit of intake superheat, the lower limit of intake pressure, and the upper limit of exhaust pressure are all determined by sample tests. Specifically, under each representative operating condition, the controller gradually opens the electronic expansion valve in two steps. After each step change, the controller maintains the current step count until recovery is complete, and then records the intake superheat and intake pressure at that step count. When the intake superheat first continuously decreases and falls below the current stable value minus three times the steady-state standard deviation, or when abnormal fluctuations occur on the compressor intake side and last for thirty seconds, the controller determines that the liquid return risk critical point has been reached and records the corresponding intake superheat and intake pressure samples. After all samples are obtained, the controller sets the lower limit of intake superheat to the mean of all liquid return critical superheat samples plus three times the standard deviation, and sets the lower limit of intake pressure to the mean of all low-pressure critical intake pressure samples plus three times the standard deviation.

[0054] During the same calibration phase, the controller also gradually closes the electronic expansion valve in two steps under each representative operating condition. After each step change, it maintains the current step number until recovery is complete, and then records the exhaust temperature and exhaust pressure under that step number.

[0055] When the exhaust temperature rises continuously and enters the range near the compressor's allowable operating limit, or the exhaust pressure rises continuously and enters the range near the machine's high-pressure protection, the controller determines that the high temperature or high pressure risk threshold has been reached and records the corresponding exhaust temperature and exhaust pressure samples.

[0056] After all samples are obtained, the controller sets the upper limit of exhaust temperature to the mean of all high-temperature critical exhaust temperature samples minus three standard deviations, and sets the upper limit of exhaust pressure to the mean of all high-pressure critical exhaust pressure samples minus three standard deviations.

[0057] If the threshold obtained in the above manner exceeds the compressor manufacturer's allowed operating range, then the more stringent side of the manufacturer's allowed operating range shall be taken as the final threshold.

[0058] During the calibration phase of the electronic expansion valve step count boundary and holding criterion, the controller first drives the electronic expansion valve to the fully closed direction and records the reference step count for the fully closed position; then it drives the electronic expansion valve to the fully open direction and records the reference step count for the fully open position. Subsequently, it performs one hundred round trip movements in the areas near the fully closed end and the fully open end, respectively, and statistically analyzes the actual step count backlash and step loss samples in the end area. The 95th percentile value is then rounded up to the integer step count to obtain the end safety margin.

[0059] In this embodiment, the end safety margin is twenty steps. The controller determines the minimum allowable number of steps for the electronic expansion valve by adding the end safety margin to the full-closed reference number, and determines the maximum allowable number of steps for the electronic expansion valve by subtracting the end safety margin from the full-open reference number. The controller continuously sends one hundred fixed step holding commands to the electronic expansion valve, each holding for sixty seconds, and reads the actual step feedback at a 0.1 second cycle.

[0060] The controller averages the absolute value of the actual step deviation during each holding process to obtain one hundred average deviation samples. Then, it adds three times the standard deviation to the sample mean and rounds up to determine the allowable step deviation for the candidate valve position. In this embodiment, the deviation threshold is two steps. The controller further counts the continuous duration of deviation exceeding the above threshold during each holding process and takes the 95th percentile value, rounding up to one second to obtain the step deviation duration threshold. In this embodiment, the duration threshold is two seconds.

[0061] During the time parameter calibration phase, the controller switches from the current electronic expansion valve step number to an adjacent candidate step number under all representative operating conditions, and records the changes in intake pressure, exhaust pressure, intake temperature, and exhaust temperature after the step number adjustment. The moment when the average rate of change of the four quantities within a 30-second sliding window is simultaneously no higher than their respective steady-state mean plus three times the standard deviation is defined as the recovery completion moment. The controller sorts all recovery completion duration samples in ascending order, takes the median and rounds it up to a multiple of 30 seconds as the single recovery check duration; and takes the 95th percentile value and rounds it up to a multiple of 30 seconds as the maximum allowable recovery check duration. In this embodiment, the single recovery check duration is 30 seconds, and the maximum allowable recovery check duration is 180 seconds. The controller records the time required for the system to reach the same recovery criterion after compressor startup, mode switching, and shutdown and restart, and takes the 95th percentile value and rounds it up to a multiple of 60 seconds as the stability judgment duration.

[0062] In this embodiment, the stability judgment time is 300 seconds. The controller also records the time required from the issuance of the step count command to the first entry of the actual step count into the allowable deviation zone of the target step count, and takes its 95th percentile value and rounds it up to one second as the step count arrival timeout.

[0063] In this embodiment, the timeout duration for step completion is ten seconds. The controller then uses ten seconds, twenty seconds, thirty seconds, forty seconds, and sixty seconds as the initial data segment lengths, respectively, to calculate the repeated test variation coefficients of the average outdoor temperature, average compressor speed, average suction pressure, and average water-side flow rate under different lengths. The shortest duration that first makes the repeated test variation coefficients of the above four quantities simultaneously less than two percent is selected as the initial data segment length. In this embodiment, the initial data segment length is thirty seconds.

[0064] During the calibration phase of single trial step size and short window cumulative revolutions, the controller changes the electronic expansion valve step size in two steps under all representative operating conditions and calculates the change range of the direction determination value. When the change range of the direction determination value caused by two consecutive step changes is less than one time the steady-state standard deviation of the direction determination value, the trial step size is determined to be too small; when the change in step size cannot be recovered within the longest allowable recovery check time, the trial step size is determined to be too large.

[0065] The controller selects the minimum step size that simultaneously satisfies the condition that the change in the direction determination value is greater than one steady-state standard deviation and that the change in the number of steps can be recovered within the longest allowable recovery check time as the single trial step size. In this embodiment, the single trial step size is eight steps. The controller then uses ten, fifteen, twenty, twenty-five, and thirty revolutions as short window lengths respectively to calculate the direction determination values ​​in three consecutive repeated tests and to calculate their coefficient of variation. The minimum cumulative number of revolutions that first makes the coefficient of variation less than five percent is selected as the short window cumulative number of revolutions. In this embodiment, the short window cumulative number of revolutions is twenty revolutions.

[0066] During the data quality threshold calibration stage, the controller calculates the proportion of effective sampling points for all stable sampling windows according to the same data cleaning, time synchronization, and filtering rules as in the subsequent online execution stage. All samples are then sorted from smallest to largest, and the 5th percentile value is rounded down to 1% to obtain the minimum allowable proportion of effective sampling points for online calculation. In this embodiment, this proportion is 95%.

[0067] The controller then takes the 25th percentile of all samples and rounds it down to 1% to obtain the high-quality recording threshold. In this embodiment, the percentage is 98%. The recording quality flag is generated according to the following rules: when the percentage of valid sampling points is not less than 98%, it is recorded as valid; when the percentage of valid sampling points is less than 98% but not less than 95%, it is recorded as restricted; when the percentage of valid sampling points is less than 95%, it is recorded as invalid.

[0068] During the stage of determining the default operating condition range half-width and minimum statistical sample size, the controller statistically analyzes the center values ​​of outdoor temperature, compressor speed, and suction pressure when the final confirmation state is reached in all calibration samples. It calculates the standard deviation of these three center values ​​respectively, and rounds up to 0.5 degrees Celsius, 50 revolutions per minute, and 0.005 MPa respectively, and uses this as the default range half-width.

[0069] In this embodiment, the default half-width of the outdoor temperature range is 2 degrees Celsius, the default half-width of the compressor speed range is 300 revolutions per minute, and the default half-width of the suction pressure range is 0.03 MPa. To determine the minimum number of records required for online adaptive update of the half-width of the range, the controller takes 10, 20, 30, 40, and 50 valid record samples respectively, compares the relative rate of change of the corresponding standard deviation estimates, and determines the minimum number of records where the relative rate of change of the standard deviation estimates of the three center values ​​is simultaneously less than 5%. In this embodiment, the minimum number of records is 30.

[0070] After completing the above basic calibration, the controller enters the online execution process.

[0071] In this embodiment, the water-side flow meter outputs volumetric flow rate in cubic meters per hour; the water-side heat exchange medium is water, with a density of 998 kg / m³ and a specific heat capacity at constant pressure of 4.186 kJ / kg Celsius. During the baseline long window, baseline short window, forward short-time step adjustment, reverse short-time step adjustment, candidate short-time pre-evaluation, and candidate long-time confirmation periods, the controller maintains the compressor target speed control strategy and the water pump control strategy unchanged. If a whole-machine protection action occurs during the above periods, the whole-machine protection is executed first, and the current round of commissioning is terminated.

[0072] During online execution, the controller first establishes the conditions for allowing debugging and determines the initial number of electronic expansion valve steps. The controller continuously reads the compressor's operating status, fault flags, defrosting flags, mode switching flags, and shutdown / restart flags. Only when the compressor has been running continuously for the full stable judgment time, is not currently in defrosting mode, has no fault codes, and no mode switching or shutdown / restart has occurred within the most recent stable judgment time, does the controller determine that the current time meets the debugging conditions. The controller keeps the current actual number of electronic expansion valve steps unchanged and continuously collects the initialization data segment, calculating the average outdoor temperature, average compressor speed, average suction pressure, and average water-side flow rate within the initialization data segment.

[0073] The effective liquid holding volume on the water side is determined by the combined volume of the buffer tank, the water-side volume of the heat exchanger, and the volume of the water-side piping, as shown in the formula:

[0074] ;

[0075] in, For the buffer water tank volume, For the water-side volume of the heat exchanger, and Let be the inner diameter and length of the i-th water pipe segment, respectively, and m be the number of water pipe segments involved in the calculation. This represents the effective liquid holding volume on the water side.

[0076] The controller calculates the water exchange time based on the effective liquid holding volume on the water side and the average water-side volumetric flow rate within the initial data segment. This water exchange time is used as the base value for the baseline long window length and the candidate long window length. If the average water-side volumetric flow rate is less than or equal to zero, the controller terminates the current round of debugging. If the water exchange time is less than 60 seconds, the long window length is set to 60 seconds. If the water exchange time is greater than 900 seconds, the current round of debugging is terminated and the current actual step count is maintained. The controller then queries the operating condition record database.

[0077] The controller prioritizes querying records with valid quality flags. If no matching record is found, it then queries records with restricted quality flags. The matching conditions are that the operating mode is the same, and the current average outdoor temperature, current average compressor speed, and current average suction pressure fall within their respective ranges. When a matching record exists, the controller determines the target matching record in the following order: minimum difference in outdoor temperature center value, minimum difference in compressor speed center value, minimum difference in suction pressure center value, and latest update time. The corresponding step number is then determined as the starting step number for the electronic expansion valve in this round. If no matching record exists, the current actual step number is maintained as the starting step number for the electronic expansion valve in this round. The controller sends a starting step number command to the electronic expansion valve driver and reads the actual step number feedback at 0.1 second intervals. If the electronic expansion valve arrives within the step arrival timeout period, the next stage begins. If it does not arrive within the step arrival timeout period, the current round of debugging is terminated.

[0078] During the baseline performance value generation phase, the controller continuously acquires data for a baseline window at the initial electronic expansion valve step count. It calculates the average water-side flow rate, average supply water temperature, average return water temperature, and average total active power within the window. The average water-side heating capacity within the baseline window is calculated based on water density, specific heat capacity at constant pressure, average volumetric flow rate, and average supply and return water temperature difference. Unit conversion between hours and seconds is also performed. The baseline performance value is calculated using the following formula:

[0079] ;

[0080] in, This is the baseline performance value. The average water-side heating capacity within the baseline long window. The average active power of the entire unit within the baseline long window;

[0081] If the average active power of the whole machine within the baseline window is less than or equal to zero, the current round of debugging will be terminated; if the proportion of effective sampling points within the baseline window is lower than the proportion of the lowest effective sampling points, the current round of debugging will be terminated.

[0082] During the direction determination reference value generation stage, the controller opens the baseline short window at the initial electronic expansion valve step number. The baseline short window is truncated according to the cumulative compressor revolutions. When the cumulative revolutions reach twenty revolutions, the short window is closed. The electrical input power per revolution within the baseline short window is calculated by the following formula:

[0083] ;

[0084] in, For each revolution of electrical input within the baseline short window, Let be the compressor drive branch voltage at time t within the baseline short window. Let be the compressor drive branch current at time t within the baseline short window. Indicates the time range of the baseline short window. The cumulative revolutions within the baseline short window are taken as 20 revolutions in this embodiment. The controller further calculates the average intake pressure, average exhaust pressure, and average intake temperature within the baseline short window, and obtains the intake enthalpy, intake entropy, intake specific volume, and isentropic exhaust enthalpy through a thermophysical property database. The theoretical compression work per revolution within the baseline short window is calculated using the following formula:

[0085] ;

[0086] in, This represents the theoretical compression work per revolution within the baseline short window. For compressor single-rotation displacement, The isentropic exhaust enthalpy corresponding to the baseline short-window average exhaust pressure and average intake entropy. This represents the inhalation enthalpy corresponding to the baseline short-window average inhalation condition. , is the intake specific volume corresponding to the average intake condition of the baseline short window, in cubic meters per kilogram; 1000 is the conversion factor between kilojoules and joules, and the direction determination benchmark value is obtained by dividing the theoretical compression work per revolution in the baseline short window by the electrical input work per revolution in the baseline short window;

[0087] The controller finds the corresponding saturation temperature based on the average intake pressure within the baseline short window, and obtains the baseline intake superheat by the difference between the average intake temperature and the saturation temperature. The controller simultaneously samples the intake pressure, exhaust pressure, intake temperature, and exhaust temperature one by one to calculate the rate of change, and calculates the average rate of change of the four monitored quantities within the baseline short window as the subsequent recovery judgment benchmark. If the proportion of effective sampling points within the baseline short window is lower than the proportion of the lowest effective sampling points, the current round of debugging is terminated.

[0088] During the forward and reverse short-time step adjustment phases, the controller first performs a forward short-time step adjustment. The controller sequentially checks whether the current exhaust temperature is lower than the upper limit of the exhaust temperature, whether the current intake superheat is higher than the lower limit of the intake superheat, whether the current intake pressure is higher than the lower limit of the intake pressure, whether the current exhaust pressure is lower than the upper limit of the exhaust pressure, and whether the initial step number plus the single trial step size is not greater than the maximum allowable step number of the electronic expansion valve. Only when all the above conditions are met simultaneously will the controller send an opening direction target step number command to the electronic expansion valve driver. If the electronic expansion valve reaches its position within the step number timeout period, the forward short window will be opened; if it does not reach its position within the step number timeout period, the current round of debugging will be terminated.

[0089] The acquisition, lookup, and calculation process for the positive short window is the same as that for the baseline short window, resulting in a positive direction determination value. After the positive short window ends, the controller restores the electronic expansion valve to the initial step number and enters the recovery check segment. The length of each recovery check segment is the duration of a single recovery check. When the average change rate of the four items is not higher than the corresponding average change rate of the baseline, the recovery is considered complete. If the conditions are not met simultaneously, the next recovery check segment is added. If the cumulative recovery check duration reaches the maximum allowable recovery check duration and the recovery is still not complete, the current round of debugging is terminated and the initial step number is maintained.

[0090] After confirming that the electronic expansion valve has returned to the initial step count, the controller performs a reverse short-term step count adjustment. The judgment order for the reverse direction is the same as that for the forward direction, except that the last judgment is changed to whether the initial step count minus the single trial step length is not less than the minimum allowable step count of the electronic expansion valve. If the condition is met, a command to reduce the target step count in the closing direction is sent. If the target step count is reached within the timeout period, a reverse short window is opened. If the target step count is not reached within the timeout period, the current round of debugging is terminated. After the reverse short window ends, the controller restores the electronic expansion valve to the initial step count again and completes the recovery judgment according to the aforementioned recovery check method to obtain the reverse direction judgment value. If only one direction meets the execution condition, only the direction judgment value for the corresponding direction is generated. If neither direction meets the condition, the short-term step count adjustment is not performed in this round, and the initial step count is directly used as the final execution step count, and the baseline performance value is used as the final confirmation value.

[0091] During the candidate valve position determination stage, when a positive direction judgment value has been generated and is higher than the direction judgment benchmark value, and a negative direction judgment value has not been generated or the positive direction judgment value is not lower than the negative direction judgment value, the number of steps corresponding to the opening direction is determined as the candidate valve position. When a negative direction judgment value has been generated and is higher than the direction judgment benchmark value, and a positive direction judgment value has not been generated or the negative direction judgment value is higher than the positive direction judgment value, the number of steps corresponding to the closing direction is determined as the candidate valve position. When none of the generated direction judgment values ​​are better than the direction judgment benchmark value, or when no short-term step adjustment is performed in either direction, the starting step number is directly used as the final execution step number, and the baseline performance value is directly used as the final confirmation value.

[0092] During the short-term pre-evaluation and long-term confirmation phases of the candidate valve position, when the candidate valve position differs from the initial electronic expansion valve step number, the controller first adjusts the electronic expansion valve to the candidate valve position and performs a confirmation of its position.

[0093] If the target is not reached within the timeout period, the current round of debugging will be terminated. The length of the candidate short-term pre-evaluation segment is determined in two steps: First, half of the water change time is taken as the basic length of the pre-evaluation; then, the time required for a cumulative 20 revolutions at the current compressor speed is calculated. If half of the water change time is less than the time required for the cumulative revolutions plus 10 seconds, the length of the candidate short-term pre-evaluation segment is taken as the time required for the cumulative revolutions plus 10 seconds; if half of the water change time is not less than the time required for the cumulative revolutions plus 10 seconds, half of the water change time is taken. The additional 10 seconds are derived from the 95th percentile statistical result of the time required for the monitoring parameters to stabilize again after the short window calculation in the representative working condition sample.

[0094] During the short-term pre-evaluation phase of the candidate, the controller first collects data for a cumulative twenty revolutions in a short-window manner and calculates the candidate direction judgment value. Then, it continuously collects exhaust temperature, intake superheat, intake pressure, exhaust pressure, and the actual number of steps of the electronic expansion valve.

[0095] The failure of short-term pre-assessment is defined as the candidate direction judgment value being lower than the direction judgment benchmark value; the triggering of the safety boundary by monitoring parameters is defined as the exhaust temperature reaching or exceeding the upper limit of exhaust temperature, or the intake superheat reaching or falling below the lower limit of intake superheat, or the intake pressure reaching or falling below the lower limit of intake pressure, or the exhaust pressure reaching or exceeding the upper limit of exhaust pressure; the failure of the electronic expansion valve to maintain the candidate valve position is defined as the deviation between the actual number of steps of the electronic expansion valve and the candidate valve position exceeding the allowable number of steps deviation, and the allowable duration is continuously allowed.

[0096] If any of the following occurs: short-term pre-assessment fails, monitoring parameters trigger safety boundaries, or the electronic expansion valve fails to remain in the candidate valve position, the controller immediately reverts the electronic expansion valve to the starting step number and determines the starting step number as the final execution step number, and determines the baseline performance value as the final confirmation value. This reversion rule takes precedence over the candidate performance value improvement conclusion.

[0097] When the short-term pre-evaluation of the candidate is completed without any rejection, the controller continues to execute the long-term confirmation phase of the candidate in the candidate valve position. The length of the long-term confirmation phase is the water change time. The controller calculates the average water-side flow rate, average supply water temperature, average return water temperature, and average total active power within the long-term confirmation phase. The average water-side heating capacity within the long-term confirmation phase is calculated based on the water density, specific heat capacity at constant pressure, average volumetric flow rate, and average supply and return water temperature difference. The controller also performs unit conversion between hours and seconds. The candidate performance value is calculated using the following formula:

[0098] ;

[0099] in, Candidate performance values, The average water-side heating capacity within the candidate long window. The average active power of the entire unit within the candidate long window;

[0100] If any monitoring parameter triggers a safety boundary during the candidate long-term confirmation period, or if the proportion of valid sampling points within the candidate long window is lower than the proportion of the lowest valid sampling points, the controller will return the electronic expansion valve to the starting step number, and set the starting step number as the final execution step number, and set the baseline performance value as the final confirmation value. When the candidate long-term confirmation is completed without any return, the controller compares the candidate performance value with the baseline performance value. If the candidate performance value is higher than the baseline performance value, the controller sets the candidate valve position as the final execution step number and the candidate performance value as the final confirmation value; if the candidate performance value is not higher than the baseline performance value, the controller returns the electronic expansion valve to the starting step number, and sets the starting step number as the final execution step number, and sets the baseline performance value as the final confirmation value.

[0101] During the generation, updating, and retrieval phase of the operating condition record library, after obtaining the final execution steps and the final confirmation value, the controller first performs an entry determination. Only when the following conditions are met simultaneously is writing to the operating condition record library allowed: First, the proportion of valid sampling points in the data window corresponding to the final confirmation value is not lower than the proportion of the lowest valid sampling points; Second, the final confirmation value is greater than zero; Third, no whole-machine protection action is triggered in the corresponding confirmation window; Fourth, the final execution steps do not deviate from the allowable step deviation in the corresponding confirmation window and do not continue for the allowable duration.

[0102] When the entry conditions are met, the controller generates a record of the current operating conditions based on the data window corresponding to the final execution step. If the final execution step is the starting step, the average outdoor temperature, average compressor speed, and average suction pressure within the baseline long window are used as the record center value. If the final execution step is the candidate valve position, the average outdoor temperature, average compressor speed, and average suction pressure within the candidate long window are used as the record center value.

[0103] The controller then determines the proportion of valid sampling points currently being recorded. When the proportion of valid sampling points is not lower than the high-quality recording threshold, the recording quality flag is marked as valid; when the proportion of valid sampling points is lower than the high-quality recording threshold but not lower than the minimum valid sampling point proportion, the recording quality flag is marked as restricted; when the proportion of valid sampling points is lower than the minimum valid sampling point proportion, the recording quality flag is marked as invalid.

[0104] In this embodiment, only valid and restricted records are allowed to enter the update comparison process; invalid records are not written to the database.

[0105] The controller extracts the most recent 30 records from the record library that are in the same operating mode and whose record quality is marked as "valid". If there are 30 or more valid records, the controller calculates the standard deviation of the center value of outdoor temperature, the center value of compressor speed and the center value of suction pressure, and rounds up to 0.5 degrees Celsius, 50 rpm and 0.005 MPa respectively, as the half-width of the current operating condition. If there are fewer than 30 valid records, the controller adopts the default half-width of the range obtained during the factory calibration stage, which is 2 degrees Celsius, 300 rpm and 0.03 MPa respectively.

[0106] The controller writes the operating mode, outdoor temperature center value, outdoor temperature range upper and lower limits, compressor speed center value, compressor speed range upper and lower limits, suction pressure center value, suction pressure range upper and lower limits, final execution steps, final confirmation value, record quality flag, and update time into a current record. When there is no record matching the current operating condition in the operating condition record library, a new record is appended. When there is a matching record in the operating condition record library, the controller determines the target matching record in the following order: minimum outdoor temperature center difference, minimum compressor speed center difference, minimum suction pressure center difference, and latest update time.

[0107] The controller first compares the recorded quality flags, and then compares the final confirmed values: if the current recorded quality flag is higher than the target matching record, the current record is retained; if the two recorded quality flags are the same, the record with the higher final confirmed value is retained; if the current recorded quality flag is lower than the target matching record, the target matching record is retained. In subsequent operation, when the controller meets the allowed debugging conditions again, it first obtains the current average outdoor temperature, current average compressor speed, and current average suction pressure in the above manner, and then queries the operating condition record library accordingly; if a matching record exists, the step number corresponding to the retained record is called as the starting electronic expansion valve step number for this round; if no matching record exists, the current actual step number is maintained as the starting electronic expansion valve step number for this round. Regardless of whether the historical records are called, the controller re-executes the complete debugging process in this embodiment.

[0108] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for intelligent energy-saving commissioning and energy efficiency optimization of a heat pump unit, characterized in that, Includes the following steps: Collect unit operating parameters to determine the starting number of electronic expansion valve steps for this round of commissioning; At the initial electronic expansion valve step number, a baseline performance value is generated based on water-side parameters and overall machine power, and a direction determination benchmark value is generated based on compressor drive branch parameters and intake and exhaust parameters. When the safety boundary is met in each adjustment direction and the corresponding target number of steps is within the allowable number of steps of the electronic expansion valve, a short-term step adjustment is performed in the corresponding direction to generate a direction determination value for the corresponding direction and determine the candidate valve position. When the candidate valve position is different from the starting electronic expansion valve step number, a short-term pre-evaluation is first performed based on the compressor drive branch parameters and suction and discharge parameters. If the pre-evaluation fails, the process returns to the starting electronic expansion valve step number, and the starting electronic expansion valve step number is determined as the final execution step number, and the baseline performance value is determined as the final confirmation value. After the pre-evaluation passes, a long-term confirmation is performed based on the water-side parameters and the overall power to obtain the candidate performance value. Based on the comparison results between the candidate performance values ​​and the baseline performance values, the final number of execution steps and the final confirmation value are determined, and the final number of execution steps, the final confirmation value, and the corresponding operating conditions are updated to the operating condition record library.

2. The intelligent energy-saving commissioning and energy efficiency optimization method for heat pump units according to claim 1, characterized in that, The water-side parameters include water flow rate, supply water temperature, and return water temperature. The compressor drive branch parameters and suction and exhaust parameters include compressor drive branch voltage, compressor drive branch current, compressor speed, suction pressure, exhaust pressure, suction temperature, and exhaust temperature. The total power is the total active power. The safety boundaries include the upper limit of exhaust temperature, the lower limit of suction superheat, the lower limit of suction pressure, the upper limit of exhaust pressure, the minimum allowable number of steps of the electronic expansion valve, and the maximum allowable number of steps of the electronic expansion valve.

3. The intelligent energy-saving commissioning and energy efficiency optimization method for heat pump units according to claim 2, characterized in that, The determination of the initial electronic expansion valve step number for this round of debugging includes: When the unit meets the requirements of continuous and stable operation, is not in defrosting state, has no fault codes, and has not experienced mode switching or shutdown and restart within a preset time, query the operating condition record database. When there are matching records with the same operating mode and whose current average outdoor temperature, current average compressor speed, and current average suction pressure fall into the corresponding intervals, the nearest neighbor matching is performed in sequence according to the difference in outdoor temperature, the difference in compressor speed, and the difference in suction pressure. The number of steps corresponding to the matching record is determined as the starting number of electronic expansion valve steps. If no matching record exists, maintain the current actual step count as the starting electronic expansion valve step count.

4. The intelligent energy-saving commissioning and energy efficiency optimization method for heat pump units according to claim 3, characterized in that, The generated baseline performance values ​​include: The water-side parameters and total power of the unit are collected within a baseline window at the initial electronic expansion valve step number. The ratio of the average water-side heating capacity to the average total active power of the unit within the baseline window is calculated as the baseline performance value. The generation direction determination benchmark value includes: At the initial electronic expansion valve step, the compressor drive branch parameters and intake and exhaust parameters are collected within a baseline short window. The ratio of theoretical compression work per revolution to electrical input work per revolution within the short window is calculated and used as the reference value for direction determination.

5. The intelligent energy-saving commissioning and energy efficiency optimization method for heat pump units according to claim 4, characterized in that, The execution of short-term step adjustment includes: When the opening direction meets the safety boundary and the target step number corresponding to the opening direction is not greater than the maximum allowable step number of the electronic expansion valve, a short-term step number adjustment is performed along the opening direction based on the initial electronic expansion valve step number and a positive direction judgment value is generated. After restoring the electronic expansion valve to the initial electronic expansion valve step number and completing the restoration judgment, when the safety boundary is met in the closing direction and the target step number corresponding to the closing direction is not less than the minimum allowable step number of the electronic expansion valve, a short-term step number adjustment is performed along the closing direction and a reverse direction judgment value is generated. The recovery determination is based on the rate of change of the inhalation pressure, exhaust pressure, inhalation temperature, and exhaust temperature.

6. The intelligent energy-saving commissioning and energy efficiency optimization method for heat pump units according to claim 5, characterized in that, The process of determining candidate valve positions and performing short-term pre-evaluation includes: When a positive direction judgment value has been generated and is higher than the direction judgment reference value, and a negative direction judgment value has not been generated or the positive direction judgment value is not lower than the negative direction judgment value, the number of steps corresponding to the opening direction is determined as the candidate valve position. When the reverse direction judgment value has been generated and is higher than the direction judgment reference value, and the forward direction judgment value has not been generated or the reverse direction judgment value is higher than the forward direction judgment value, the number of steps corresponding to the closing direction is determined as the candidate valve position. When none of the generated direction determination values ​​are better than the direction determination reference value, or when neither the opening direction nor the closing direction has been adjusted in a short time step, the initial electronic expansion valve step number is determined as the final execution step number, and the baseline performance value is determined as the final confirmation value. When the candidate valve position is different from the initial electronic expansion valve step number, the electronic expansion valve is first controlled to reach the candidate valve position, and then a short-term pre-evaluation is performed based on the compressor drive branch parameters and suction and discharge parameters. If the short-term pre-assessment fails, the monitoring parameters trigger the safety boundary, or the electronic expansion valve fails to remain in the candidate valve position, the electronic expansion valve is returned to the initial electronic expansion valve step number, and the initial electronic expansion valve step number is determined as the final execution step number, and the baseline performance value is determined as the final confirmation value.

7. The intelligent energy-saving commissioning and energy efficiency optimization method for heat pump units according to claim 6, characterized in that, The long-term confirmation includes: Under the candidate valve position, collect the water-side parameters and total power within a candidate long window, and calculate the ratio of the average water-side heating capacity to the average total active power of the candidate long window as the candidate performance value. When the candidate performance value is higher than the baseline performance value, the candidate valve position is determined as the final execution step, and the candidate performance value is determined as the final confirmation value. When the candidate performance value is not higher than the baseline performance value, or when a safety boundary is triggered during the candidate long window, the starting electronic expansion valve step number is determined as the final execution step number, and the baseline performance value is determined as the final confirmation value.

8. The intelligent energy-saving commissioning and energy efficiency optimization method for heat pump units according to claim 7, characterized in that, The update to the operating condition record database includes: The operating mode, outdoor temperature range, compressor speed range, and suction pressure range are used as operating conditions, and the corresponding center value, final number of execution steps, final confirmation value, and record quality flag are written into the operating condition record library. If there is no record matching the current operating condition in the operating condition record database, a new record is appended and written. When a matching record exists in the operating condition record library, the nearest neighbor match is performed in sequence according to the difference in the center value of outdoor temperature, the difference in the center value of compressor speed, and the difference in the center value of suction pressure to determine the target matching record. The record quality flag is compared first, and when the record quality flags are the same, the record corresponding to the one with the higher final confirmed value is retained.

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