CN-121739609-B - Screw type water-cooling chiller unit device and low-temperature operation method

CN121739609BCN 121739609 BCN121739609 BCN 121739609BCN-121739609-B

Abstract

The invention relates to the field of data processing and air conditioning, in particular to a screw type water-cooling chiller unit device and a low-temperature operation method. The method comprises the steps of obtaining monitoring data of a water cooling chiller, calculating a condensation side performance attenuation index, calculating an evaporation side liquid supply stability index, determining the product of the condensation side performance attenuation index and the evaporation side liquid supply stability index as a system coupling response index, calculating an oil circuit safety margin index, multiplying the oil circuit safety margin index by the system coupling response index after reciprocal and carrying out normalization processing to obtain an adaptive compensation factor of the water cooling chiller under low-temperature operation, determining the product of the adaptive compensation factor and a preset maximum oil circuit adjustment quantity as an adjustment compensation increment of the oil circuit system, and carrying out compensation adjustment on the oil circuit system according to the adjustment compensation increment. The invention can improve the operation safety and coordination of the screw water-cooling chiller.

Inventors

XU HUALONG
WANG XIAOBO
WANG ZHIQIN
Wu Qizhao
SHANG YIBO
ZHANG LEI
LI GUOYUAN

Assignees

聚瑞芯光电有限公司

Dates

Publication Date: 20260508
Application Date: 20260226

Claims (10)

1. The low-temperature operation method of the screw water-cooling chiller unit is characterized by comprising the following steps of: Acquiring monitoring data of the water cooling chiller in response to the cooling water temperature of the water cooling chiller being lower than the condensation temperature of the current running refrigerant; calculating a condensing side performance decay index for characterizing the degree of deterioration of the heat exchange performance of the condenser based on the pressure data and the temperature data of the condenser in the monitoring data; calculating an evaporation side liquid supply stability index for characterizing the supply stability of the evaporator liquid refrigerant based on the liquid refrigerant flow data of the evaporator inlet in the monitoring data; determining the product of the condensation side performance decay index and the evaporation side liquid supply stability index as a system coupling response index for representing the response sensitivity of the evaporation end to the change of the condensation end; Calculating an oil way safety margin index for representing the stability of a lubricating oil feedback path based on oil discharge pressure data and oil return pressure data of the screw compressor in the monitoring data; Taking the reciprocal of the oil circuit safety margin index, multiplying the reciprocal by the system coupling response index, and carrying out normalization treatment to obtain a self-adaptive compensation factor of the water-cooling unit under low-temperature operation; and determining the product of the self-adaptive compensation factor and the preset maximum oil way adjustment quantity as an adjustment compensation increment of the oil way system, and performing compensation adjustment on the oil way system according to the adjustment compensation increment so as to maintain the stability of the oil return pressure of the lubricating oil.
2. The method for low-temperature operation of a screw water chiller according to claim 1, wherein the calculating the condensation side performance degradation index for characterizing the degradation degree of the heat exchange performance of the condenser based on the pressure data and the temperature data of the condenser in the monitored data comprises: calculating a condensation side phase change driving force deviation coefficient for representing the phase change thermodynamic deviation degree of the refrigerant based on the pressure data and the temperature data of the condenser; Calculating a liquid phase formation rate decay parameter for characterizing a liquid phase formation capacity based on temperature data and pressure data of the condenser; And determining the product of the liquid phase generation rate attenuation parameter and the condensation side phase change driving force deviation coefficient as a condensation side performance attenuation index.
3. The method for low-temperature operation of a screw water-cooling chiller according to claim 2, wherein the pressure data of the condenser is pressure data within an observation time window of a preset time length, and the calculating of the condensation side phase change driving force deviation coefficient for representing the phase change thermal deviation degree of the refrigerant based on the pressure data and the temperature data of the condenser specifically comprises: determining the ratio of the average value of condensing pressure of the water cooling chiller under a set reference working condition to the average value of pressure data in a preset time length as a deviation amplification factor of the pressure data; For each moment in the observation time window, determining a theoretical saturated pressure value according to the thermodynamic property of the refrigerant based on the temperature of the moment, acquiring an actual pressure value of the moment, and calculating the absolute value of the difference between the saturated pressure value and the actual pressure value as an instantaneous pressure deviation value of the moment; obtaining instantaneous pressure deviation values at all moments, and averaging to obtain an average pressure deviation value; And determining the product of the deviation amplification factor and the average pressure deviation value as a condensing side phase change driving force deviation coefficient.
4. The method for low-temperature operation of a screw water chiller according to claim 2, wherein the temperature data of the condenser is temperature data within an observation time window of a preset time length, and the calculating of the liquid phase generation rate attenuation parameter for representing the liquid phase generation capacity based on the temperature data and the pressure data of the condenser specifically comprises: For each moment in the observation time window, determining a theoretical saturated temperature value according to the thermodynamic property of the refrigerant based on the pressure of the moment, acquiring an actual temperature value of the moment, calculating a difference value between the theoretical saturated temperature value and the actual temperature value, and carrying out normalization processing on the difference value to obtain a normalized supercooling degree value of the moment; calculating the ratio of the normalized supercooling degree value of each moment except the last moment in the observation time window to the normalized supercooling degree value of the next moment to obtain the instantaneous change rate of the liquid phase generating capacity of the moment; and obtaining an average value of the instantaneous change rate of the liquid phase generating capacity at all moments to obtain the attenuation parameter of the liquid phase generating rate.
5. The method as set forth in claim 1, wherein the calculating the evaporation side liquid supply stability index for characterizing the supply stability of the evaporator liquid refrigerant based on the liquid refrigerant flow data of the evaporator inlet in the monitoring data comprises: Based on an observation time window with a preset time length, acquiring liquid refrigerant flow data of an evaporator inlet in the window, wherein the liquid refrigerant flow data is time sequence data; Averaging the flow data of the liquid refrigerant at all moments in the current observation time window to obtain the average flow value of the liquid refrigerant in the current observation time window; Acquiring a reference liquid refrigerant flow value, and taking the ratio of the reference liquid refrigerant flow value to the average flow value of the liquid refrigerant in the current observation time window as a flow reference deviation parameter of the current observation time window; calculating a flow transient fluctuation parameter for characterizing transient fluctuation characteristics within a current observation time window based on the liquid refrigerant flow data; And multiplying the flow reference deviation parameter and the flow transient fluctuation parameter of the current observation time window to obtain the evaporation side liquid supply stability index.
6. The method for low-temperature operation of a screw water chiller according to claim 5 wherein the calculating flow transient fluctuation parameters for characterizing transient fluctuation characteristics within a current observation time window based on liquid refrigerant flow data comprises: calculating an instantaneous change rate sequence of data change with time at each moment according to the liquid refrigerant flow data; And calculating the average value of absolute values of differences between all adjacent two instantaneous change rates in the instantaneous change rate sequence as a flow instantaneous fluctuation parameter.
7. The method for low-temperature operation of a screw water chiller according to claim 1, wherein the calculating the oil way safety margin index for characterizing the stability of the oil return path based on the oil discharge pressure data and the oil return pressure data of the screw compressor in the monitoring data comprises: acquiring time sequence data of oil discharge pressure and oil return pressure of the screw compressor in an observation time window with preset time length; According to the time sequence data, calculating the absolute value of the difference between the oil discharge pressure and the oil return pressure at each moment in the window to be used as the actual pressure difference at each moment; calculating a safety deviation coefficient for representing the deviation of the average differential pressure from a safety target degree based on the actual differential pressure at all times; Calculating a differential pressure fluctuation coefficient for characterizing the instantaneous fluctuation characteristic of the actual differential pressure based on the time-varying sequence of the actual differential pressure; And multiplying the safety deviation coefficient by the pressure difference fluctuation coefficient to obtain the oil circuit safety margin index.
8. The method for low-temperature operation of a screw water chiller according to claim 7 wherein the calculating a safety deviation factor for characterizing the deviation of the average differential pressure from a safety target based on the actual differential pressure at all times comprises: calculating the average value of the actual pressure difference at all moments to obtain the average actual pressure difference; Acquiring the lowest safe target pressure difference value; and calculating the reciprocal of the absolute value of the difference between the lowest safe target pressure difference value and the average actual pressure difference as a safe deviation coefficient.
9. The method for low-temperature operation of a screw water chiller according to claim 7 wherein the calculating of the differential pressure fluctuation coefficient for characterizing the transient fluctuation characteristics thereof based on the time-varying sequence of actual differential pressure comprises: calculating the average value of the absolute values of the difference values of all adjacent two actual differential pressures in the actual differential pressure sequence, and taking the average value as the average differential pressure fluctuation amplitude; And calculating the reciprocal of the average pressure difference fluctuation amplitude as a pressure difference fluctuation coefficient.
10. A screw water chiller plant comprising a screw compressor, a condenser, an evaporator, a cooling tower, an oil circuit system, and a control system, wherein the control system is configured to perform the screw water chiller plant low temperature operation method of any one of claims 1 to 9.

Description

Screw type water-cooling chiller unit device and low-temperature operation method Technical Field The invention relates to the field of data processing and air conditioning, in particular to a screw type water-cooling chiller unit device and a low-temperature operation method. Background The screw water-cooling chiller is one of the most widely used central air-conditioning and process cold source equipment in the industry and commercial architecture at present. The screw compressor drives the refrigerant to circulate, realizes water side heat exchange, and provides stable chilled water for electronic manufacturing, precision machining, food refrigeration, chemical process control, various production equipment with high requirements on refrigerating capacity and temperature stability, clean environment and comfortable air conditioning systems. The machine set has the remarkable advantages of high energy efficiency, wide load adjusting range, high structural reliability and the like, and is widely applied to a plurality of key fields. However, when the unit is operated in a low temperature environment (such as winter or cold regions), a series of key technical problems and operation risks caused by the excessively low condensing pressure are faced: And when the temperature of the external environment is too low, the temperature of the cooling water is obviously reduced, so that the heat exchange of the condenser is excessive. This results in a significant drop in refrigerant condensing pressure, which is difficult to maintain in a reasonably efficient operating interval when the compressor is operating at very low pressure ratios. Meanwhile, the gas phase density of the refrigerant is reduced under low condensing pressure, so that the refrigerating capacity per unit volume is reduced, the efficiency of the whole refrigeration cycle is obviously reduced, and the cooling capacity of the unit is reduced. More serious, the excessively low condensing pressure can directly lead to the reduction of the exhaust pressure of the compressor, so that the oil way pressure difference driving force for driving the lubricating oil to return to the crankcase of the compressor from the low pressure side of the system is seriously insufficient. Lubricating oil can not effectively flow back, moving parts (such as bearings and screw rotors) in the compressor are prone to lubrication failure, severe mechanical faults such as oil film breakage and bearing dry grinding are extremely easy to cause irreversible serious damage to a unit, and the operation safety of the whole system is threatened. The conventional control method is difficult to effectively solve the coupling problem at the same time, so that the efficiency of the unit for high-efficiency optimization under the low-temperature condition is low. Disclosure of Invention The invention provides a screw water-cooling chiller device and a low-temperature operation method, which aim to solve the existing problems. The invention relates to a low-temperature operation method of a screw water-cooling chiller, which adopts the following technical scheme: the embodiment of the invention provides a low-temperature operation method of a screw water-cooling chiller, which comprises the following steps: Acquiring monitoring data of the water cooling chiller in response to the cooling water temperature of the water cooling chiller being lower than the condensation temperature of the current running refrigerant; calculating a condensing side performance decay index for characterizing the degree of deterioration of the heat exchange performance of the condenser based on the pressure data and the temperature data of the condenser in the monitoring data; calculating an evaporation side liquid supply stability index for characterizing the supply stability of the evaporator liquid refrigerant based on the liquid refrigerant flow data of the evaporator inlet in the monitoring data; determining the product of the condensation side performance decay index and the evaporation side liquid supply stability index as a system coupling response index for representing the response sensitivity of the evaporation end to the change of the condensation end; Calculating an oil way safety margin index for representing the stability of a lubricating oil feedback path based on oil discharge pressure data and oil return pressure data of the screw compressor in the monitoring data; Taking the reciprocal of the oil circuit safety margin index, multiplying the reciprocal by the system coupling response index, and carrying out normalization treatment to obtain a self-adaptive compensation factor of the water-cooling unit under low-temperature operation; and determining the product of the self-adaptive compensation factor and the preset maximum oil way adjustment quantity as an adjustment compensation increment of the oil way system, and performing compensation adjustment on the oil way system according to the adjus