Proportioning method for low-temperature adaptive refrigerant oil and refrigerant of double-rotor compressor

Abstract

The invention discloses a matching method for low-temperature adaptive refrigerant oil and refrigerant of a double-rotor compressor, belongs to the technical field of refrigeration cycle optimization of vehicle air conditioners, and provides a general and low-cost integral solution aiming at the problems of high viscosity of refrigerant oil, single refrigerant adaptation and easiness in avoidance at low temperature in the prior art. The method comprises the following steps: selecting POE (Polyolefin Elastomer) synthetic refrigeration oil which has kinematic viscosity of 32mm < 2 > / s at 40 DEG C and pour point of less than or equal to-40 DEG C and is mutually soluble with multiple refrigerants; according to the physical properties of different refrigerants such as R32, R410A, R134a, R1234yf, R290, R454B and R452B, the charging amount is adjusted to be 95%-108% of the rated value in a differentiated mode; and the pipeline is purged by adopting nitrogen with the pressure of 0.8-1.0 MPa before filling. According to the scheme, the structure of the compressor does not need to be changed, the cost is only increased by 3%-5%, the double-rotor compressor can stably operate at the low temperature of-15 DEG C or below, the heating capacity at the environment temperature of-12 DEG C can be kept at 3500 W or above, the double-rotor compressor is matched with current mainstream and future novel environment-friendly refrigerants, and the patent protection range and the application scene are effectively expanded.

Description

Technical Field

[0001] This invention belongs to the field of automotive air conditioning refrigeration cycle optimization technology. This invention discloses a method for the ratio of low-temperature adaptable refrigeration oil and refrigerant in a dual-rotor compressor. Background Technology

[0002] When the ambient temperature is below -10°C, the viscosity of conventional refrigeration oil in automotive twin-rotor overhead air conditioning units increases significantly, leading to poor compressor lubrication, insufficient refrigerant circulation, and a substantial reduction in heating capacity. Existing solutions mostly focus on replacing the compressor with a high-pressure resistant one or using a specific single refrigerant, but these solutions are costly and have poor system compatibility.

[0003] With increasingly stringent global environmental regulations, automotive air conditioning refrigerants are showing a trend towards diversification. In addition to mainstream refrigerants such as R32, R410A, R134a, R1234yf, and R290, low Global Warming Potential (GWP) blends like R454B and R452B, as environmentally friendly alternatives to R410A, are increasingly widely used in integrated rooftop air conditioning units. Different refrigerants exhibit significant differences in physical properties such as operating pressure, miscibility with refrigeration oil, and charge sensitivity, posing challenges to stable system operation at low temperatures.

[0004] Existing technologies include several improved refrigeration oil solutions targeting specific refrigerants or specific low-temperature compatibility. For example, Chinese invention patent CN107828460A discloses a refrigeration oil whose base oil is a polyol ester obtained by reacting specific mixed fatty acids (valeric acid, heptanoic acid, and hexanoic acid) with polyols. This solution aims to improve the compatibility of the refrigeration oil with R410A or R32 refrigerants in the 0°C to -15°C range, preventing stratification and thus eliminating the need for auxiliary heating components. However, this technical solution is specifically targeted at and limited to R410A and R32 refrigerants, and does not address or solve the compatibility issues of various refrigerants such as R134a, R1234yf, R290, R454B, and R452B in a wider temperature range (e.g., below -15°C), thus limiting its application scope.

[0005] For example, Chinese invention patent CN105754682A discloses a compressor refrigeration oil and refrigerant mixture specifically for R161 refrigerant. It uses naphthenic mineral oil as the base oil and adds specific antioxidants and light absorbers to maintain the stability of R161 refrigerant at high temperatures. This approach is a typical "one oil, one refrigerant" dedicated formulation. While it solves the stability problem of a specific refrigerant (R161), it is completely unsuitable for other refrigerants with vastly different properties, lacking versatility. Furthermore, its focus on temperature ranges differs from the low-temperature lubrication and circulation problems addressed by this invention.

[0006] In summary, existing technologies mostly focus on improving the compatibility of single or a few refrigerants within a specific temperature range by modifying the refrigeration oil formulation, representing a "point-to-point" solution. However, given the diverse and rapidly evolving market of automotive air conditioning refrigerants, such solutions have significant drawbacks: 1) Narrow compatibility, failing to cover a wide range of refrigerants from mainstream to new low-GWP types, limiting product versatility and market adaptability; 2) Easily circumvented, competitors can bypass patent protection based on a single refrigerant by simply replacing the refrigerant type; 3) Failure to systematically address low-temperature performance issues, particularly by failing to consider the differences in the physical properties of different refrigerants and finely adjust the charge amount to optimize overall cycle performance and heating capacity in low-temperature conditions below -15℃.

[0007] Therefore, there is an urgent need to propose a low-cost, universal solution that can be adapted to a variety of refrigerants (including existing mainstream models and new environmentally friendly alternatives), and to systematically solve the problems of lubrication guarantee and cooling and heating cycle efficiency of twin-rotor compressors in harsh low-temperature environments by combining the selection of refrigeration oil with the adjustment of differentiated refrigerant charge. Summary of the Invention

[0008] To address the issues of narrow compatibility, easy circumvention, and insufficient low-temperature performance of existing technologies, this invention provides a versatile, low-cost, and easy-to-operate low-temperature adaptable refrigeration oil and multi-refrigerant ratio scheme for twin-rotor compressors. This scheme achieves stable lubrication, efficient refrigerant circulation, and reliable heating performance in harsh low-temperature environments below -15°C by selecting low-viscosity, highly miscible synthetic refrigeration oils and combining them with a differentiated charging strategy for multiple refrigerants.

[0009] This invention includes the following technical solutions: A method for mixing low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor includes the following steps: Step S1, Refrigeration oil selection: Select a synthetic refrigeration oil suitable for low-temperature conditions below -15℃, wherein the kinematic viscosity of the synthetic refrigeration oil at 40℃ is 32 mm. 2 / s, pour point ≤-40℃, and has good miscibility with a variety of refrigerants; Step S2, Refrigerant Charge Adjustment: Adjust the refrigerant charge to 95% to 108% of the target air conditioning system's rated charge, depending on the type of refrigerant selected. Step S3, Adaptation Verification: Start the compressor and run it for a preset time. Detect the compressor's operating current and exhaust temperature. If the operating current is within the range of 8A to 10A and the exhaust temperature is within the range of 75℃ to 85℃, then the adaptation is confirmed to be complete.

[0010] Furthermore, in the above-mentioned method for mixing low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor, the refrigerant is selected from at least one of R32, R410A, R134a, R1234yf, R290, R454B and R452B.

[0011] Furthermore, in the above-mentioned method for mixing low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor, the synthetic refrigeration oil is a POE-type refrigeration oil with a kinematic viscosity of 5 mm at 100°C. 2 / s to 7 mm 2 / s.

[0012] Furthermore, in the above-mentioned method for mixing low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor, when the refrigerant is R32, its charging amount is 105% to 108% of the rated charging amount.

[0013] Furthermore, in the above-mentioned method for mixing low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor, when the refrigerant is R290, its charging amount is 95% to 100% of the rated charging amount.

[0014] Furthermore, in the above-mentioned method for mixing low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor, when the refrigerant is R410A, R134a or R1234yf, its charging amount is 100% to 102% of the rated charging amount.

[0015] Furthermore, in the above-mentioned method for mixing low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor, when the refrigerant is R454B or R452B, its charging amount is 102% to 105% of the rated charging amount.

[0016] Furthermore, in the above-mentioned method for mixing low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor, in step S2, the refrigerant is charged by weighing, and the charging accuracy error is ≤ ±5g.

[0017] Furthermore, in the above-mentioned method for matching the ratio of refrigeration oil and refrigerant for low-temperature adaptation of a twin-rotor compressor, the preset time in step S3 is 30 minutes; after the initial verification is completed, the compressor needs to run continuously for at least 4 hours without any abnormal alarms or shutdowns in order to be considered as a successful final adaptation.

[0018] Furthermore, the above-mentioned method for mixing low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor includes a pretreatment step before performing step S1: purging the compressor pipeline with nitrogen gas at a pressure of 0.8 MPa to 1.0 MPa for a duration of not less than 5 minutes.

[0019] Compared with the prior art, the present invention has the following outstanding advantages: 1. Effectively improves low-temperature performance: The selected low-pour-point and low-viscosity POE synthetic refrigeration oil can maintain good fluidity and lubrication performance in low-temperature environments below -15℃, effectively solving the problems of compressor starting difficulties, increased wear and poor refrigerant circulation caused by increased oil viscosity at low temperatures, and ensuring the reliability of system operation in severe cold conditions.

[0020] 2. Achieve universal compatibility with multiple refrigerants: The provided POE refrigeration oil exhibits excellent miscibility with various refrigerants, including R32, R410A, R134a, R1234yf, R290, R454B, and R452B. By scientifically setting differentiated charge ratios (95%-108%) based on the physical properties of each refrigerant, the same basic solution can flexibly adapt to current mainstream and future environmentally friendly alternative refrigerants, significantly improving the solution's versatility and market adaptability.

[0021] 3. Balancing cost and convenience: The entire solution only involves the precise adjustment of refrigeration oil replacement and refrigerant charge, without requiring structural modifications to the compressor body or system piping. Therefore, the implementation cost is relatively low (estimated cost increase is only 3%-5%), and the operation steps are clear and simple, making it easy to promote and apply in production and after-sales processes.

[0022] 4. Comprehensive improvement of system performance: According to the test, the system using this solution can maintain a stable heating capacity of about 3500W in a low temperature environment of -12℃. At the same time, key parameters such as compressor operating current and exhaust temperature are maintained within a reasonable range, achieving a balance between heating efficiency and operational stability in low temperature environments. Attached Figure Description

[0023] Figure 1 A comparison of heating performance and operating parameters at -12℃; Figure 2 Comparison of total wear (mg) of key components; Figure 3 The change rate of kinematic viscosity of refrigeration oil at 40℃. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] The refrigerant information for this invention is shown in Table 1 below.

[0026] Example 1 Low-temperature mixing scheme for R32 refrigerant A method for mixing refrigeration oil and refrigerant in a low-temperature twin-rotor compressor, the specific steps of which are as follows: System pretreatment: Completely drain the existing refrigerant oil from the twin-rotor compressor system in the automotive overhead unit. Purge the internal pipelines of the compressor with dry nitrogen at a pressure of 0.9 MPa for 5 minutes.

[0027] Refrigeration oil filling: Add synthetic refrigeration oil to the compressor, the amount of oil being 100% of the compressor's rated oil capacity. The synthetic refrigeration oil is POE 32, with a kinematic viscosity of 32 mm² / s at 40°C, a kinematic viscosity of 6 mm² / s at 100°C, and a pour point of -45°C.

[0028] Refrigerant charging: A high-precision electronic scale is used to charge the system with R32 refrigerant by weighing. The rated charging amount of the system is set to 1.2 kg, and the actual charging amount is adjusted to 106% of the rated charging amount, that is, 1.272 kg is charged.

[0029] Compatibility verification: After filling is complete, start the compressor. Proceed to the operation verification process.

[0030] Example 2 Low-temperature mixing scheme for R290 refrigerant A method for mixing refrigeration oil and refrigerant in a low-temperature twin-rotor compressor, the specific steps of which are as follows: System pretreatment: Same as step 1 in Example 1, nitrogen purging is performed.

[0031] Refrigeration oil filling: Same as step 2 in Example 1, add POE 32 synthetic refrigeration oil.

[0032] Refrigerant charging: R290 refrigerant is charged into the system using the weighing method. The system's rated charge is 1.2 kg, and the actual charge is adjusted to 98% of the rated charge, i.e., 1.176 kg is charged.

[0033] Adaptation verification: Same as step 4 in Example 1, start the compressor to verify operation.

[0034] Example 3 Low-temperature mixing scheme for R454B refrigerant A method for mixing refrigeration oil and refrigerant in a low-temperature twin-rotor compressor, the specific steps of which are as follows: System pretreatment: Same as step 1 in Example 1, nitrogen purging is performed.

[0035] Refrigeration oil filling: Same as step 2 in Example 1, add POE 32 synthetic refrigeration oil.

[0036] Refrigerant charging: R454B refrigerant is charged into the system using the weighing method. The system's rated charge is 1.2 kg, and the actual charge is adjusted to 104% of the rated charge, i.e., 1.248 kg is charged.

[0037] Adaptation verification: Same as step 4 in Example 1, start the compressor to verify operation.

[0038] Example 4 Low-temperature mixing scheme for R410A refrigerant A method for mixing refrigeration oil and refrigerant in a low-temperature twin-rotor compressor, the specific steps of which are as follows: System preprocessing: Same as step 1 in Example 1.

[0039] Adding refrigeration oil: Same as step 2 in Example 1.

[0040] Refrigerant charging: R410A refrigerant is charged into the system using the weighing method. The system's rated charge is 1.2 kg, and the actual charge is adjusted to 101% of the rated charge, i.e., 1.212 kg is charged.

[0041] Adaptation verification: Same as step 4 in Example 1.

[0042] Example 5 Low-temperature mixing scheme for R1234yf refrigerant A method for mixing refrigeration oil and refrigerant in a low-temperature twin-rotor compressor, the specific steps of which are as follows: System preprocessing: Same as step 1 in Example 1.

[0043] Adding refrigeration oil: Same as step 2 in Example 1.

[0044] Refrigerant charging: R1234yf refrigerant is charged into the system using the weighing method. The system's rated charge is 1.2 kg, and the actual charge is adjusted to 101% of the rated charge, i.e., 1.212 kg is charged.

[0045] Adaptation verification: Same as step 4 in Example 1.

[0046] Comparative Example 1 Only the POE refrigeration oil was replaced, but the refrigerant charge was not adjusted. A compressor processing method, the specific steps of which are as follows: System preprocessing: Same as step 1 in Example 1.

[0047] Refrigeration oil filling: Same as step 2 in Example 1, add POE 32 synthetic refrigeration oil.

[0048] Refrigerant charging: R32 refrigerant was charged into the system using the weighing method. The system's rated charging amount is 1.2 kg, and the actual charging amount was strictly 1.200 kg, without any proportional adjustment.

[0049] Verification: Same as step 4 in Example 1.

[0050] Comparative Example 2 Uses standard PAG refrigeration oil and is compatible with R32 refrigerant. A compressor processing method, the specific steps of which are as follows: System preprocessing: Same as step 1 in Example 1.

[0051] Refrigeration oil filling: Add regular PAG 46 refrigeration oil (kinematic viscosity at 40°C is about 46 mm² / s, pour point is about -35°C) to the compressor, and fill the oil to 100% of the rated oil volume.

[0052] Refrigerant charging: Same as step 3 in Example 1, charge 1.272 kg of R32 refrigerant.

[0053] Verification: Same as step 4 in Example 1.

[0054] Comparative Example 3 The filling volume exceeds the recommended range of this invention. A compressor processing method, the specific steps of which are as follows: System preprocessing: Same as step 1 in Example 1.

[0055] Adding refrigeration oil: Same as step 2 in Example 1.

[0056] Refrigerant charging: R32 refrigerant was charged into the system using a weighing method. The system's rated charge is 1.2 kg, and the actual charge was adjusted to 112% of the rated charge (i.e., 1.344 kg), which is significantly higher than the range described in the claims of this invention.

[0057] Verification: Same as step 4 in Example 1.

[0058] Comparative Example 4 Nitrogen purging pretreatment step omitted A compressor processing method, the specific steps of which are as follows: Old oil purging: Only the original refrigeration oil in the compressor system is completely purged, without nitrogen purging.

[0059] Adding refrigeration oil: Same as step 2 in Example 1.

[0060] Refrigerant charging: Same as step 3 in Example 1.

[0061] Verification: Same as step 4 in Example 1.

[0062] Comparative Example 5 Use existing technology (CN107828460A) to adapt refrigeration oil to R454B refrigerant.

[0063] A compressor processing method, the specific steps of which are as follows: System pretreatment: Same as step 1 in Example 1, use dry nitrogen gas at a pressure of 0.9 MPa to purge the compressor pipeline for 5 minutes.

[0064] Refrigeration oil filling: Add the polyol ester refrigeration oil prepared in Example 1 of Comparative Document 1 (CN107828460A) to the compressor, with the filling amount being 100% of the compressor's rated oil capacity. This refrigeration oil is a polyol ester obtained by reacting trimethylolpropane with a mixture of fatty acids (molar ratio 35%:25%:40%) composed of valeric acid, heptanoic acid, and hexanoic acid, and contains specific additives.

[0065] Refrigerant charging: R454B refrigerant was charged into the system using the weighing method. The system's rated charging amount is 1.2 kg. For comparison, the charging amount was set to 104% of the rated charging amount (i.e., 1.248 kg), referring to the recommended range for R454B refrigerant in this invention.

[0066] Verification: Same as step 4 in Example 1, start the compressor to verify operation.

[0067] Test Example 1 Heating capacity and operational stability test in low-temperature environment (-12℃) Objective: To verify the superiority of the present invention (specific POE refrigeration oil + differentiated charge) over conventional solutions at low temperatures in terms of key parameters such as heating capacity, operating current and exhaust temperature.

[0068] method: Test sample preparation: Select the same model of vehicle roof-mounted integrated air conditioning system after processing three schemes: Example 1 (adapted to R32), Comparative Example 1 (POE oil but the filling amount was not adjusted), and Comparative Example 2 (conventional PAG oil).

[0069] Test environment: The three systems were placed in a walk-in environmental simulation chamber, and the ambient temperature was set to -12℃±0.5℃ and the humidity to ≤30%.

[0070] Test process: The system was left to stand for more than 8 hours in the test environment to allow the internal temperature of the system to fully balance with the environment.

[0071] Start the system in the rated thermal mode and run it until the operating conditions are stable (usually 30 minutes after startup).

[0072] Key parameters were continuously recorded for the first 4 hours after system startup using a data acquisition instrument (model: Agilent 34972A): Heating capacity: Calculated using the air enthalpy difference method, with high-precision temperature and humidity sensors (accuracy: temperature ±0.1℃, humidity ±1%RH) and airflow hoods installed at the air outlet and return air outlet.

[0073] Compressor operating current: Measured using a clamp power meter (model: Hioki 3390).

[0074] Compressor exhaust temperature: Measured using a type K thermocouple (accuracy ±0.5℃) attached to the surface of the exhaust pipe.

[0075] Observe and record whether the system experiences any abnormal alarms or shutdowns.

[0076] Results: See Table 2.

[0077] Conclusion: The solution of this invention (Example 1) achieved the highest heating capacity (3520W) at a low temperature of -12℃, and the operating current and exhaust temperature were both within the optimal range, indicating system stability. Comparative Example 1 suffered a significant decrease in heating capacity due to insufficient refrigerant charge; Comparative Example 2 failed to operate normally due to poor lubrication and excessive load caused by the excessively high low-temperature viscosity of conventional PAG oil. This demonstrates that the synergy between "POE refrigeration oil" and "precise refrigerant charge adjustment" is indispensable for ensuring both low-temperature heating performance and operational stability.

[0078] Test Example 2 Multi-refrigerant compatibility and system circulation efficiency test Objective: To verify the universal compatibility of the present invention with different refrigerants (including mainstream and new low-GWP refrigerants) and to evaluate its system circulation efficiency.

[0079] method: Test sample preparation: Four systems were selected: Example 1 (R32), Example 2 (R290), Example 3 (R454B) and Comparative Example 5 (using the oil described in CN107828460A + R454B).

[0080] Test environment: Ambient temperature set to -12℃.

[0081] Test metrics: System performance coefficient: Under stable heating conditions, the heating capacity of the system and the compressor input power (measured by a power meter) are measured to calculate the heating performance coefficient.

[0082] Intake and exhaust pressure ratio: The ratio of intake and exhaust pressures during stable operation of the compressor is measured using a pressure sensor and calculated, reflecting the compressor load and system circulation resistance.

[0083] Oil return observation: After running for 4 hours, quickly shut down the system and disassemble it to observe the oil level and oil condition inside the compressor, and evaluate the miscibility of the refrigeration oil and refrigerant and the oil return effect.

[0084] Results: See Table 3 and Figure 1 .

[0085] Conclusion: When using the solutions of this invention (Examples 1-3) to adapt to different refrigerants, the systems all exhibited high and similar coefficients of performance, with reasonable suction and discharge pressure ratios and good oil return. However, in Comparative Example 5, when using a special oil optimized for R410A / R32 to adapt to R454B, the coefficient of performance decreased significantly, the pressure ratio increased, and the oil return was slightly worse. This demonstrates that the POE32 refrigeration oil selected in this invention has excellent broad-spectrum miscibility. Combined with adjustments to the charge amount for different refrigerants, it can achieve efficient and stable adaptation to various refrigerants, reflecting the versatility of the solution.

[0086] Test Example 3 Long-term operational reliability and critical component condition testing Objective: To verify the protective effect of the present invention (including nitrogen purging pretreatment) on the long-term reliable operation of the compressor.

[0087] method: Test sample preparation: Two systems were selected: Example 1 (complete process) and Comparative Example 4 (nitrogen purging omitted).

[0088] Accelerated endurance test: A continuous start-stop cycle test (50 minutes of operation followed by 10 minutes of shutdown) was conducted for 500 hours in a cyclic temperature environment of -12°C to -15°C.

[0089] Post-test detection: Wear analysis: After the test, the compressor was disassembled and the mass loss of key moving parts such as pistons and vanes was measured using a precision balance (accuracy 0.1mg) to calculate the wear.

[0090] Physicochemical analysis of oil: Take out a sample of refrigeration oil from the compressor and test its kinematic viscosity change rate at 40℃ and acid value increase.

[0091] Impurity content: The residual oil was filtered using a 0.45μm filter membrane, dried, and then weighed for residual impurities.

[0092] Oil return effect evaluation: Measure the percentage of the oil level in the compressor cavity relative to the rated oil level after the compressor has been shut down and left to stand for 24 hours.

[0093] Results: See Table 4 and Figure 2-3 .

[0094] Conclusion: After long-term accelerated testing, the system in Comparative Example 4 (omitting nitrogen purging) exhibited serious reliability problems: wear of key components increased by nearly 4.5 times, oil viscosity increased significantly and acid value surged due to contamination and oxidation, the content of mechanical impurities in the system was an order of magnitude higher, and there was significant insufficient oil return. In contrast, Example 1, employing the complete solution of this invention, maintained excellent levels of all indicators, with minimal wear, stable oil, and a clean system. The data sufficiently and significantly demonstrate that nitrogen purging pretreatment plays an irreplaceable and crucial role in removing manufacturing and old oil residues and ensuring the initial cleanliness of the lubrication system. This step, combined with subsequent application of specialized refrigeration oil and precise charging, constitutes a complete technical solution to ensure the compressor achieves ultra-long lifespan and high reliability under harsh low-temperature conditions; none of these steps can be omitted.

[0095] It is worth noting that the above description of the embodiments focuses on illustrating the technical solution of the present invention, rather than precisely defining its scope of protection. Those skilled in the art should understand that appropriate adjustments and optimizations can be made based on the technical details disclosed in the embodiments of the present invention, or equivalent substitutions can be implemented for individual or even all technical elements. Such adjustments and substitutions will not deviate from the core essence of the technical solution of the present invention and should be included within the technical protection scope of the embodiments of the present invention. In short, the protection of the present invention should not be limited to the concrete presentation of the above embodiments, but broadly covers all equivalent changes and improvements that do not depart from its basic concept. In summary, the protection definition of the present invention should be based on the statement of the claims, and the above embodiments are only used as a reference guide for understanding the present invention.

Claims

1. A method for proportioning refrigeration oil and refrigerant for a low-temperature adapted twin-rotor compressor, characterized in that, Includes the following steps: Step S1, Refrigeration oil selection: Select a synthetic refrigeration oil suitable for low-temperature conditions below -15℃, wherein the kinematic viscosity of the synthetic refrigeration oil at 40℃ is 32 mm. 2 / s, pour point ≤-40℃, and has good miscibility with a variety of refrigerants; Step S2, Refrigerant Charge Adjustment: Adjust the refrigerant charge to 95% to 108% of the target air conditioning system's rated charge, depending on the type of refrigerant selected. Step S3, Adaptation Verification: Start the compressor and run it for a preset time. Detect the compressor's operating current and exhaust temperature. If the operating current is within the range of 8A to 10A and the exhaust temperature is within the range of 75℃ to 85℃, then the adaptation is confirmed to be complete.

2. The method for proportioning low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor according to claim 1, characterized in that, The refrigerant is selected from at least one of R32, R410A, R134a, R1234yf, R290, R454B and R452B.

3. The method for proportioning low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor according to claim 1, characterized in that, The synthetic refrigeration oil is a POE-type refrigeration oil with a kinematic viscosity of 5 mm at 100°C. 2 / s to 7 mm 2 / s.

4. The method for proportioning low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor according to claim 2, characterized in that, When the refrigerant is R32, its charge amount is 105% to 108% of the rated charge amount.

5. The method for proportioning low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor according to claim 2, characterized in that, When the refrigerant is R290, its charge amount is 95% to 100% of the rated charge amount.

6. The method for proportioning low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor according to claim 2, characterized in that, When the refrigerant is R410A, R134a or R1234yf, its charge amount is 100% to 102% of the rated charge amount.

7. The method for proportioning low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor according to claim 2, characterized in that, When the refrigerant is R454B or R452B, its charge amount is 102% to 105% of the rated charge amount.

8. The method for proportioning low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor according to any one of claims 1 to 7, characterized in that, In step S2, the refrigerant is charged by weighing, and the charging accuracy error is ≤ ±5g.

9. The method for proportioning low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor according to any one of claims 1 to 7, characterized in that, In step S3, the preset time is 30 minutes; after the initial verification is completed, the compressor must run continuously for at least 4 hours without any abnormal alarms or shutdowns in order to be considered as a successful final adaptation.

10. The method for proportioning low-temperature adaptable refrigeration oil and refrigerant in a twin-rotor compressor according to any one of claims 1 to 7, characterized in that, Before performing step S1, a pretreatment step is also included: purging the compressor pipeline with nitrogen gas at a pressure of 0.8 MPa to 1.0 MPa for a duration of not less than 5 minutes.

Images