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CN-121993935-A - Refrigerant dynamic filling process based on complete machine simulation operation

CN121993935ACN 121993935 ACN121993935 ACN 121993935ACN-121993935-A

Abstract

The invention discloses a refrigerant dynamic charging process based on complete machine simulation operation, and belongs to the technical field of air conditioners and heat pumps. The method aims to solve the problems that the existing refrigerant filling depends on a static target value and cannot adapt to individual differences and working condition changes of a system. The method comprises the steps of constructing a digital twin simulation model of an air conditioning system to be filled, starting the system to operate under a preset simulation working condition, collecting first operation parameters, carrying out initialization calibration on the model, dynamically filling refrigerants with a preset step length, continuously collecting real-time second operation parameters, feeding back the second operation parameters to the model, carrying out online fitting of a change curve of parameters such as supercooling degree and superheat degree along with the filling amount based on real-time data, predicting the refrigerant amount when the energy efficiency ratio of the system reaches the optimal filling target, and judging that filling is completed when the parameters collected in real time and the extreme value area predicted by the model are converged. The invention realizes the dynamic and accurate filling of 'measuring and tailoring' type for each specific air conditioning system, and remarkably improves the filling precision and the system operation energy efficiency.

Inventors

  • GENG LING

Assignees

  • 上海辉卓制冷设备有限公司

Dates

Publication Date
20260508
Application Date
20260331

Claims (10)

  1. 1. The refrigerant dynamic charging process based on the complete machine simulation operation is applied to an air conditioner or a heat pump system, and is characterized by comprising the following steps of: The method comprises the steps of S1, connecting an air conditioning system (100) to be filled with a refrigerant filling machine, and establishing a digital twin simulation model corresponding to a physical entity of the air conditioning system (100) to be filled, wherein the digital twin simulation model is configured to receive real-time operation parameters of the air conditioning system (100) to be filled and dynamically correct model parameters; S2, a simulation operation stage, namely starting an air conditioning system (100) to be filled and operating the air conditioning system in a preset simulation working condition mode, collecting a first operation parameter set of the air conditioning system (100) to be filled in the simulation working condition mode in real time, synchronously inputting the first operation parameter set into the digital twin simulation model, and carrying out initialization calibration on the model; Step S3, controlling the refrigerant filling machine to dynamically fill the refrigerant into the air conditioning system (100) to be filled at a preset step length and a preset speed, continuously collecting a second operation parameter set of the air conditioning system (100) to be filled in real time in the filling process, and feeding the second operation parameter set back to the calibrated digital twin simulation model; s4, in a convergence judging stage, comparing the second operation parameter set acquired in real time with the system performance index predicted by the digital twin simulation model, and judging that filling is completed when the deviation between the second operation parameter set and the system performance index is within a preset convergence threshold range and the system performance index reaches or approaches to a predicted extremum region; And S5, controlling the refrigerant filling machine to stop filling and recording the final filling quantity in a termination stage.
  2. 2. The refrigerant dynamic charging process based on complete machine simulation operation according to claim 1, wherein the preset simulation working condition mode in the step S2 comprises a refrigeration mode or a heating mode, and at least two different system internal throttling or air volume combination states are constructed by adjusting the opening degree of an electronic expansion valve (140), the rotating speed of an indoor fan and the rotating speed of an outdoor fan in an air conditioning system (100) to be charged so as to excite the dynamic response characteristic of the system.
  3. 3. The refrigerant dynamic charging process based on complete machine simulation operation according to claim 1, wherein the second operation parameter set in the step S3 at least comprises a compressor (110) suction pressure, a compressor (110) discharge pressure, a compressor (110) suction temperature, a compressor (110) discharge temperature, a condenser middle temperature, a condenser outlet temperature, an evaporator outlet temperature, an electronic expansion valve (140) opening, a compressor (110) operation frequency and a compressor (110) input power.
  4. 4. The refrigerant dynamic charging process based on complete machine simulation operation according to claim 3, wherein the specific method for dynamically generating the optimal charging target amount by the digital twin simulation model in step S3 comprises the following steps: Step S31, calculating a real-time supercooling degree (SC) and a real-time superheat degree (SH) based on a second operation parameter set fed back in real time; step S32, associating the real-time supercooling degree (SC) and the real-time superheat degree (SH) with the charge amount variation (Δm), and performing online fitting to generate a real-time supercooling degree variation curve sc=f (Δm) and a real-time superheat degree variation curve sh=g (Δm); Step S33, the digital twin simulation model predicts the inflection point position of the system Energy Efficiency Ratio (EER) or coefficient of performance (COP) according to a preset objective function and combines the derivative changes of sc=f (Δm) and sh=g (Δm), and determines the refrigerant quantity predicted value corresponding to the inflection point as the optimal charge target quantity.
  5. 5. The refrigerant dynamic charging process based on complete machine simulation operation as set forth in claim 4, wherein the convergence determination in the step S4 further comprises monitoring a slope d (SC)/d (Δm) of the real-time supercooling degree variation curve sc=f (Δm), and triggering the first charging termination signal when the slope becomes zero from a positive value or becomes negative from zero.
  6. 6. The refrigerant dynamic charging process based on complete machine simulation operation as set forth in claim 4, wherein the convergence determination in the step S4 further comprises monitoring a trend of change of the discharge temperature of the compressor (110), and triggering a second charging termination signal when the discharge temperature of the compressor (110) presents a turning point of decreasing before increasing in the charging process.
  7. 7. The refrigerant dynamic charging process based on complete machine simulation operation according to any one of claims 1-6, wherein before starting the air conditioning system (100) to be charged in step S2, the process further comprises performing a vacuum pumping operation on the air conditioning system (100) to be charged, and maintaining the vacuum level below a preset threshold for at least 15 minutes to check the air tightness of the system.
  8. 8. The refrigerant dynamic charging process based on complete machine simulation operation according to any one of claims 1-6, wherein the digital twin simulation model is built in a controller of the refrigerant charging machine or in an upper computer in communication connection with an air conditioning system (100) to be charged and the refrigerant charging machine.
  9. 9. A refrigerant dynamic charging system for realizing the refrigerant dynamic charging process based on complete machine simulation operation as set forth in any one of claims 1-8, comprising: an air conditioning system (100) to be filled comprises a compressor (110), a condenser, an evaporator, an electronic expansion valve (140) and corresponding temperature sensors and pressure sensors; the refrigerant filling unit (200) is connected with a refrigerant circulation loop of the air conditioning system (100) to be filled through an openable and closable pipeline and is used for accurately controlling and metering the filling amount of the refrigerant; The data acquisition and control unit (300) is electrically connected with each sensor of the air conditioning system (100) to be filled and the refrigerant filling unit (200) and is used for acquiring operation parameters in real time and sending control instructions; And the digital twin simulation unit (400) is in data interaction with the data acquisition and control unit (300), is internally provided with a dynamic simulation model of the air conditioning system (100) to be filled, and is used for receiving real-time data, carrying out model calibration, predicting the optimal filling amount and feeding back decision information to the data acquisition and control unit (300).
  10. 10. A computer readable storage medium having stored thereon a computer program, which when executed by a processor, performs the steps of a refrigerant dynamic charging process based on a simulation run of a complete machine as claimed in any one of claims 1 to 8.

Description

Refrigerant dynamic filling process based on complete machine simulation operation Technical Field The invention relates to the technical field of air conditioners and heat pumps, in particular to a refrigerant dynamic filling process based on complete machine simulation operation, and specifically relates to a refrigerant filling method, system and medium for dynamic optimization based on complete machine simulation operation and digital twin technology. Background The performance, efficiency and reliability of air conditioning and heat pump systems (hereinafter referred to as air conditioning systems) are largely dependent on the charge of refrigerant (refrigerant) in the system. The insufficient filling amount can lead to the reduction of refrigerating/heating capacity of the system, the overhigh exhaust temperature, poor lubrication of the compressor and even burning of the compressor when serious, and the excessive filling amount can lead to the increase of condensing pressure, the increase of power consumption of the compressor and the reduction of energy efficiency ratio, possibly cause liquid impact risk and increase of greenhouse gas emission. Therefore, the realization of accurate refrigerant filling is a key technology in the links of air conditioner production, installation and maintenance. In addition, with the increasing complexity of air conditioning system design, such as popularization of frequency conversion technology, application of electronic expansion valves and rapid development of multi-split system, sensitivity of the system to refrigerant filling amount is higher and higher. A small filling deviation may lead to a large fluctuation in the energy efficiency of the system and even to a disturbance of the control logic. Thus, industry demands for filling accuracy have increased from the original "gram level" to the "lean gram level". At present, common refrigerant filling methods in the industry are mainly divided into several types: One type is a quantitative filling method, namely, according to the rated filling amount marked on an air conditioner nameplate, the air conditioner nameplate is directly weighed and filled through an electronic scale. However, the method cannot adapt to the internal volume change of the system caused by the factors of the length difference of the connecting pipes in the installation site, the drop difference of indoor and outdoor machines and the like, and often causes poor actual operation effect. Another type is a parameter monitoring method, for example, chinese patent application with publication number CN104990320A discloses a control method and system for automatic refrigerant filling, which comprises the steps of S1, detecting outdoor environment temperature T1 and air conditioner pressure value P1, S2, inquiring the lowest pressure value Ps corresponding to the outdoor environment temperature T1 according to a lowest pressure corresponding table, S3, judging whether Ps is more than or equal to P1, if so, starting an electromagnetic valve of a refrigerant storage device to carry out refrigerant addition, and re-executing S1, if not, starting a compressor of the refrigerant storage device, after refrigerating operation time T, executing S4, detecting outlet temperature T2 of an air conditioner condenser, S5, judging whether DeltaT is more than or equal to, if so, starting the electromagnetic valve of the refrigerant storage device to carry out refrigerant addition, and re-executing S4, if not, judging that the refrigerant addition is sufficient, and stopping refrigerant addition. The invention can ensure that the refrigerant adding amount of the air conditioning system is accurate when the air conditioning system is installed or maintained, reduce the refrigerant calculating process of the installation and the maintenance, and ensure the high reliability of the air conditioning system. The outdoor environment temperature and the system pressure are detected and compared with a preset table to judge whether filling is needed. Although the method considers environmental factors, the control logic is simple, and depending on static and universal empirical data, the method cannot accurately adjust the individual characteristics (such as compressor efficiency difference and heat exchanger performance deviation) of each specific air conditioning system. Yet another class is a method of filling based on subcooling or superheat, as described in chinese patent publication No. CN102893096B, which describes a method of filling an HVAC system by determining the relationship of the liquid line temperature of the HVAC system, the suction line pressure of the HVAC system, and the outdoor ambient temperature of the HVAC system. A method of charging an HVAC system by adjusting an amount of refrigerant in the HVAC system to approach a target minimum liquid line temperature. A method of priming an HVAC system by testing the HVAC system according to at least three set