CN-121993941-A - Method and device for estimating refrigerant stock of refrigeration system and refrigeration system

CN121993941ACN 121993941 ACN121993941 ACN 121993941ACN-121993941-A

Abstract

The embodiment of the invention provides a method and a device for estimating refrigerant stock of a refrigeration system and the refrigeration system. The method comprises the steps of obtaining first temperature information and first pressure information of a refrigerant at an outlet of a condenser, obtaining second temperature information of the refrigerant at an inlet of an expansion valve, determining the supercooling degree of the outlet of the condenser according to the first pressure information and the first temperature information, judging that abnormal flash gas exists in a refrigerating system according to the difference between the supercooling degree of the outlet of the condenser and a preset supercooling degree threshold value, calculating the flash gas ratio according to the first temperature information and the second temperature information and the vaporization latent heat of the refrigerant under the first pressure information, correcting the supercooling degree of the outlet of the condenser to obtain corrected supercooling degree, and estimating the refrigerant stock of the refrigerating system according to the corrected supercooling degree of the outlet of the condenser and a refrigerant stock correlation model. The technical scheme provided by the embodiment can improve the accuracy of quality estimation of the refrigerant stock.

Inventors

FANG ZHONGCHENG
Huang Guopu
LI YONGBING

Assignees

江苏拓米洛高端装备股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260311

Claims (10)

1. A method for estimating refrigerant charge of a refrigeration system, comprising: Acquiring first temperature information of refrigerant at outlet of condenser And first pressure information Second temperature information of refrigerant at inlet of expansion valve ; According to the first pressure information of the condenser outlet And first temperature information of refrigerant at outlet of said condenser Determining a degree of subcooling of the condenser outlet ; According to the supercooling degree of the condenser outlet The difference between the abnormal flash gas and a preset supercooling degree threshold value is judged to exist in the refrigerating system; according to the first temperature information And the second temperature information And the refrigerant is in the first pressure information Calculating flash gas ratio and correcting supercooling degree of condenser outlet Obtaining corrected supercooling degree; And estimating the refrigerant storage of the refrigerating system based on the corrected supercooling degree of the condenser outlet and the refrigerant storage correlation model according to the corrected supercooling degree of the condenser outlet.
2. The method according to claim 1, wherein the first temperature information is based on And the second temperature information And the refrigerant is in the first pressure information Calculating flash gas ratio and correcting supercooling degree of condenser outlet Obtaining the corrected supercooling degree comprises: according to the first temperature information And the second temperature information The product of the difference value of the constant pressure specific heat capacity of the refrigerant in the supercooling liquid state and the first pressure information of the refrigerant The ratio of vaporization latent heat under the condition, calculating the flash gas ratio ; Calculating a flash gas correction coefficient according to the flash gas ratio; According to the correction coefficient of flash gas and the supercooling degree of the condenser outlet And determining the corrected supercooling degree.
3. The method according to claim 1 or 2, wherein the first pressure information according to the condenser outlet And first temperature information of refrigerant at outlet of said condenser Determining a degree of subcooling of the condenser outlet Comprising: According to the first pressure information of the condenser outlet Determining first pressure information of the condenser outlet Saturation temperature of corresponding refrigerant ; According to the first temperature information of the refrigerant at the outlet of the condenser And the saturation temperature To determine the degree of supercooling of the condenser outlet 。
4. The method according to claim 1 or 2, further comprising, before estimating the refrigerant charge of the refrigeration system based on the corrected subcooling degree of the condenser outlet and a refrigerant charge correlation model according to the corrected subcooling degree of the condenser outlet: And determining a corrected supercooling degree and refrigerant stock correlation model of a condenser outlet of the refrigeration system according to the calibration experiment.
5. The method of claim 4, wherein the determining the subcooling of the condenser outlet of the refrigeration system is based on a calibration experiment A model associated with refrigerant charge, comprising: setting a calibration working condition, wherein the calibration working condition comprises an ambient temperature, an evaporator load and a compressor frequency; Filling refrigerants with different qualities into the refrigerating system, starting from 70% of the designed refrigerant quantity, taking 5% of the designed refrigerant quantity as a step length, and ending to 130% of the designed refrigerant quantity, performing a calibration experiment, and respectively calculating corrected supercooling degrees of the condenser outlets corresponding to the refrigerant storage quantities of all experimental groups And recording the quality of the corresponding refrigerant stock; And (3) based on the quality of the refrigerant stock and the corrected supercooling degree of the corresponding condenser outlet of the calibration experiment, adopting least square fitting to obtain a correlation model of the corrected supercooling degree of the condenser outlet and the refrigerant stock.
6. The method according to claim 1 or 2, further comprising, after estimating the refrigerant charge of the refrigeration system based on the corrected supercooling degree of the condenser outlet and a refrigerant charge correlation model according to the corrected supercooling degree of the condenser outlet: acquiring the current operation condition of the refrigeration system; correcting the corrected supercooling degree and refrigerant stock correlation model of the condenser outlet according to the difference between the current operation working condition and the calibration working condition, and determining the corrected supercooling degree and refrigerant stock correlation model of the condenser outlet after working condition correction; based on a corrected supercooling degree and refrigerant stock correlation model of a condenser outlet subjected to working condition correction, estimating the refrigerant stock according to the corrected supercooling degree of the condenser outlet.
7. The method of claim 6, wherein the modifying the modified subcooling degree and refrigerant inventory correlation model for the condenser outlet based on the difference between the current operating condition and the calibration operating condition, determining the modified subcooling degree and refrigerant inventory correlation model for the condenser outlet based on the operating condition modification, comprises: Obtaining the ambient temperature of the current operation condition ) An evaporator load (Q) and a compressor frequency (f); Ambient temperature according to current operating conditions ) And the ambient temperature under the calibration working condition ) The difference value, the evaporator load (Q) of the current operation condition and the evaporator load under the calibration condition ) The difference value, the compressor frequency (f) of the current operation condition and the compressor frequency under the calibration condition ) And correcting the corrected supercooling degree and refrigerant storage correlation model of the condenser outlet by the difference value to obtain the corrected supercooling degree and refrigerant storage correlation model of the condenser outlet after working condition correction.
8. The method according to any one of claims 1,2, 5, or 7, further comprising, after estimating a refrigerant inventory of the refrigeration system based on the corrected subcooling degree of the condenser outlet and a refrigerant inventory correlation model, after estimating the refrigerant inventory of the refrigeration system: triggering refrigerant shortage early warning according to the difference between the refrigerant storage quantity and a first preset storage quantity threshold value; triggering refrigerant excess early warning according to the difference between the refrigerant stock and a second preset stock threshold; The first preset stock quantity threshold is smaller than the second preset stock quantity threshold.
9. An apparatus for estimating a refrigerant charge of a refrigeration system, comprising: The acquisition module is used for acquiring first temperature information of the refrigerant at the outlet of the condenser ) And the first pressure information ) Second temperature information of refrigerant at inlet of expansion valve ); The supercooling degree calculation module is used for calculating the supercooling degree according to the first pressure information of the condenser outlet ) And the first temperature information of the refrigerant at the outlet of the condenser ) Determining a degree of subcooling of the condenser outlet ; A flash gas judging module for judging the supercooling degree of the condenser outlet The difference between the abnormal flash gas and a preset supercooling degree threshold value is judged to exist in the refrigerating system; The supercooling degree correction module is used for correcting the supercooling degree according to the first temperature information ) And the second temperature information ) And the refrigerant is in the first pressure information ) Calculating flash gas ratio and correcting supercooling degree of condenser outlet Obtaining corrected supercooling degree; The estimating module is used for estimating the refrigerant stock of the refrigerating system based on the corrected supercooling degree of the condenser outlet and the refrigerant stock correlation model according to the corrected supercooling degree of the condenser outlet.
10. A refrigerating system is characterized by comprising a refrigerant stock estimating device of the refrigerating system, a compressor, a condenser, an expansion valve, an evaporator, a first temperature sensor, a first pressure sensor and a second temperature sensor; The compressor is connected with the condenser, the condenser is connected with the expansion valve, the expansion valve is connected with the evaporator, the evaporator is connected with the compressor, the first pressure sensor and the first temperature sensor are arranged at the outlet of the condenser, the second temperature sensor is arranged at the inlet of the expansion valve, and the first temperature sensor, the first pressure sensor and the second temperature sensor are respectively connected with a refrigerant storage estimating device of the refrigerating system.

Description

Method and device for estimating refrigerant stock of refrigeration system and refrigeration system Technical Field The embodiment of the invention relates to the technical field of refrigeration, in particular to a method and a device for estimating refrigerant stock of a refrigeration system and the refrigeration system. Background In vapor compression refrigeration systems, the refrigerant is the core medium for energy transfer, and its inventory directly determines the operational performance, energy efficiency level and reliability of the system. When the refrigerant of the system is insufficient, the problems of refrigeration/heating capacity reduction, exhaust temperature increase of the compressor, COP (coefficient of performance) reduction and the like can occur, and when the refrigerant is severe, the compressor can be damaged due to poor lubrication or overheating, and when the refrigerant is excessive, the accumulated liquid of the condenser and the evaporating pressure can be abnormal, so that the stability and the service life of the system are also influenced. Therefore, the refrigerant storage in the refrigerating system is accurately mastered, and the method has important significance for system installation and debugging, operation and maintenance and fault investigation. The existing refrigerant stock detection method for the refrigeration system has the problem of poor refrigerant stock estimation precision. Disclosure of Invention The embodiment of the invention provides a method and a device for estimating the refrigerant stock of a refrigeration system and the refrigeration system, which are used for solving the problem that the refrigerant stock estimation precision is poor in the existing method for detecting the refrigerant stock of the refrigeration system. In order to realize the technical problems, the invention adopts the following technical scheme: The embodiment of the invention provides a method for estimating the refrigerant stock of a refrigerating system, which comprises the following steps: Acquiring first temperature information and first pressure information of a refrigerant at an outlet of a condenser, and second temperature information of the refrigerant at an inlet of an expansion valve; determining the supercooling degree of the condenser outlet according to the first pressure information of the condenser outlet and the first temperature information of the refrigerant of the condenser outlet; Judging that abnormal flash gas exists in the refrigeration system according to the difference between the supercooling degree of the condenser outlet and a preset supercooling degree threshold value; calculating a flash gas ratio according to the first temperature information, the second temperature information and the vaporization latent heat of the refrigerant under the first pressure information, and correcting the supercooling degree of the outlet of the condenser to obtain corrected supercooling degree; And estimating the refrigerant storage of the refrigerating system based on the corrected supercooling degree of the condenser outlet and the refrigerant storage correlation model according to the corrected supercooling degree of the condenser outlet. Optionally, the calculating the flash gas ratio according to the first temperature information, the second temperature information and the vaporization latent heat of the refrigerant under the first pressure information, and correcting the supercooling degree of the condenser outlet to obtain the corrected supercooling degree includes: calculating a flash gas ratio according to the ratio of the product of the difference value of the first temperature information and the second temperature information and the constant pressure specific heat capacity of the refrigerant in the supercooling liquid state to the vaporization latent heat of the refrigerant in the first pressure information; calculating a flash gas correction coefficient according to the flash gas ratio; And determining the corrected supercooling degree according to the product of the flash gas correction coefficient and the supercooling degree of the condenser outlet. Optionally, the determining the supercooling degree of the condenser outlet according to the first pressure information of the condenser outlet and the first temperature information of the refrigerant of the condenser outlet includes: Determining the saturation temperature of the refrigerant corresponding to the first pressure information of the condenser outlet according to the first pressure information of the condenser outlet; And determining the supercooling degree of the condenser outlet according to the difference value between the first temperature information of the refrigerant at the condenser outlet and the saturation temperature. Optionally, before estimating the refrigerant storage of the refrigeration system based on the corrected supercooling degree of the condenser outlet and the refrig