A method of evaporator freeze testing

Abstract

The present application relates to the field of refrigeration equipment, and more particularly to a kind of evaporator freeze test method.The evaporator freeze test test bench proposed in the present application, when the medium output by the heater is shunted through the hot gas bypass valve, the state of the medium input into the input end of the condenser can be adjusted by mixing the medium passing through the hot gas bypass valve with the medium output by the compressor;When the suction amount of the compressor input end is insufficient, the medium output by the compressor can also be guided back to the compressor input port through the hot gas bypass valve to ensure the suction amount of the compressor.The medium output by the evaporator can flow to the vapor-liquid separator through the heater, and the medium output by the evaporator can be further heated through the heater, so that when the heat exchange efficiency of the evaporator is low, the liquid refrigerant that may be contained in the medium output by the evaporator can be further heated through the heater to ensure the full vaporization of the refrigerant, thereby avoiding the liquid knock phenomenon of the compressor.

Description

[0001] This case is a divisional application of invention patent 2021116518951, filed on December 30, 2021, which is an evaporator auxiliary module and an evaporator freezing test bench. Technical Field

[0002] This invention relates to the field of refrigeration equipment, and more particularly to a method for testing the freezing of evaporators. Background Technology

[0003] The principle of the evaporator freezing test is as follows: the refrigerant-side evaporation temperature in the test evaporator is generally set to around 0 degrees Celsius. The water on the test evaporator's water side is warmer than the refrigerant-side temperature, used for heat exchange with the 0-degree refrigerant on the test evaporator. The water temperature on the water side decreases to near the refrigerant-side temperature. When a high water flow rate is applied to the test evaporator's water side, the water velocity is very fast, and even if the refrigerant-side evaporation temperature is 0 degrees Celsius, no ice will form on the water side. As the water flow rate decreases, the water velocity also slows down. While the refrigerant-side evaporation temperature remains 0 degrees Celsius, when the flow rate drops to a certain value, tiny ice crystals will first form on the water side of the test evaporator. These ice crystals gradually block the channels on the water side, further reducing the water velocity and decreasing the heat exchange efficiency of the test evaporator, subsequently accelerating ice crystal formation. The chain reaction is that more water on the water side of the test evaporators rapidly decreases in velocity and freezes. Since ice has a larger volume for the same mass, for a test evaporator with a very narrow flow channel, the frozen water will burst the water-side flow channel of the test evaporator. As a result, the high-pressure refrigerant liquid will quickly flow into the water-side channel, and some of the water and refrigerant mixture will flow into the next component of the test evaporator in the system application: the compressor.

[0004] Because compressors are very sensitive to moisture content, if moisture mixes into the refrigerant lines and enters the compressor, the compressor may explode due to ice blockage, or experience cylinder scoring due to the deterioration of the refrigerant and refrigeration oil. This mixture of acidified refrigerant and refrigeration oil can also enter other components of the refrigeration system, ultimately causing damage to all components of the refrigeration system. It is very difficult to clean completely, resulting in irreparable losses.

[0005] In summary, due to the unavoidable abnormal decrease in system water flow and human error, it is crucial for water evaporators to determine the water flow rate at which freezing begins. A freezing test bench can simulate this operating condition of the evaporator and test the critical freezing water flow rate.

[0006] In traditional experiments, to determine the freezing point of an evaporator under test, a complete refrigeration system is typically configured. The heat exchange of the evaporator is used to match the compressor, condenser, and other valves and components. The water flow rate is then gradually changed. As the flow velocity within the heat exchanger decreases, ice will form inside the evaporator at a certain point. Due to increased water-side resistance, the water flow rate gradually decreases, causing a rapid drop in the refrigerant superheat at the evaporator outlet. When the compressor draws in refrigerant, it will produce a liquid slugging sound. The water flow rate and evaporation temperature at this point are then recorded. As the icing worsens, the liquid slugging in the compressor intensifies. At this point, the compressor can be shut down. Failure to shut it down promptly can cause the compressor to explode. Even if the compressor is shut down promptly after multiple liquid sluggings, it will still impact the compressor's bushings and compression chamber, causing damage. In plate heat exchangers, ice inside the evaporator can cause it to rupture. The resulting mixture of water and refrigerant, drawn into the compressor, will instantly burn out, contaminating the entire system's heat exchanger, other components, and piping. Therefore, the previous test setup was similar to a destructive test. Finding the freezing point of the evaporator also meant that the test setup would be destroyed and needed to be reconfigured. This would be a huge waste of resources. Summary of the Invention

[0007] To address the high scrap rate of components such as compressors during evaporator freezing tests in existing technologies, this invention proposes an evaporator freezing test method.

[0008] One of the objectives of this invention is to provide an evaporator auxiliary module that achieves state isolation between the evaporator output medium and the compressor input medium during evaporator freezing tests, thereby ensuring the safe operation of the compressor.

[0009] An evaporator auxiliary module includes: an evaporator inlet connection branch, an evaporator outlet connection branch, a condenser connection branch, a branch line, a first valve, a second valve, and a heater;

[0010] The first end of the condenser connection branch is used to connect to the output end of the condenser, and the first end of the evaporator inlet connection branch is used to connect to the input end of the evaporator; the first end of the branch is connected to the second end of the condenser connection branch and the second end of the evaporator inlet connection branch respectively, and the second end of the branch is connected to the input end of the heater; a first regulating valve is provided on the branch.

[0011] The first end of the evaporator output port connection branch is used to connect to the output end of the evaporator; the two ends of the first valve are respectively connected to the second end of the evaporator output port connection branch and the input end of the heater; the two ends of the second valve are respectively connected to the second end of the evaporator output port connection branch and the output end of the heater.

[0012] Preferably, a first temperature sensor and a first pressure sensor are provided on the evaporator inlet connection branch, and a second temperature sensor and a second pressure sensor are provided on the evaporator outlet connection branch.

[0013] Preferably, a second regulating valve is also provided on the evaporator inlet connection branch, and the first temperature sensor and the first pressure sensor are located on the side of the second regulating valve facing the first end of the evaporator inlet connection branch.

[0014] Preferably, a third temperature sensor and a third pressure sensor are also provided on the evaporator inlet connection branch between its second end and the second regulating valve.

[0015] Preferably, a third valve is provided on the branch line, and a fourth valve is provided on the branch line connecting the evaporator inlet.

[0016] The second objective of this invention is to provide an evaporator freezing test bench, which achieves efficient and safe evaporator freezing tests.

[0017] An evaporator freezing test bench includes: a condenser, a vapor-liquid separator, a compressor, a hot gas bypass valve, and the aforementioned evaporator auxiliary module;

[0018] The compressor's output is connected to the condenser's input; the condenser's output is connected to the first end of the condenser's connecting branch.

[0019] The heater's output is connected to the gas-liquid separator's input, and the gas-liquid separator's output is used to connect to the compressor's input. The hot gas bypass valve's two ends are connected to the heater's output and the compressor's output, respectively.

[0020] Preferably, the compressor is an open-type compressor.

[0021] Preferably, it also includes an evaporator water tank, which is equipped with a stirring device connected to the prime mover of the compressor to obtain driving force.

[0022] Preferably, the compressor output end is provided with a fourth pressure sensor, and the compressor input end is provided with a fifth temperature sensor and a fifth pressure sensor.

[0023] Preferably, it also includes a control module and a fourth temperature sensor disposed on the condenser connection branch;

[0024] The evaporator freezing test bench has two working states;

[0025] In the first working state, the branch flow is unobstructed, the first valve is closed, and the heater is working. The low-temperature and high-pressure medium output from the condenser is divided into two paths after flowing through the condenser connecting branch. The first path flows through the evaporator inlet connecting branch, the evaporator, the evaporator outlet connecting branch, and the second valve. The second path flows through the branch flow and the heater, mixes with the first path flowing through the second valve, and then enters the vapor-liquid separator.

[0026] In the second operating state, the branch flow is unobstructed, the first valve is open, the second valve is closed, and the heater is working. The low-temperature, high-pressure medium output from the condenser flows through the condenser connecting branch and is divided into two paths. The first path flows through the evaporator inlet connecting branch, the evaporator, the evaporator outlet connecting branch, and the first valve. The second path flows through the branch flow and mixes with the first path flowing through the first valve before entering the gas-liquid separator. The mixed medium is heated by the heater and then flows into the gas-liquid separator.

[0027] The control module is connected to the second temperature sensor, the second pressure sensor, the fourth temperature sensor, the first valve, the second valve, the first regulating valve, the second regulating valve, and the heater, respectively. The control module is used to adjust the working state of the first valve, the second valve, the first regulating valve, the second regulating valve, and the heater according to the detection values ​​of the second temperature sensor, the second pressure sensor, and the fourth temperature sensor, so as to switch between the first working state and the second working state.

[0028] The advantages of this invention are:

[0029] (1) The present invention proposes an evaporator auxiliary module, which provides a heater in the output direction of the evaporator. The heater can further heat the medium output by the evaporator, so that when the heat exchange efficiency of the evaporator is low, the liquid refrigerant that may be contained in the medium output by the evaporator can be further heated by the heater to ensure the full vaporization of the refrigerant, thereby avoiding liquid slugging in the compressor.

[0030] (2) The evaporator auxiliary module has a first operating state and a second operating state. In the first operating state, the second-path medium after splitting can be heated by a heater to compensate for the insufficient superheat of the medium and prevent liquid slugging in the compressor. In the second operating state, the low-temperature, high-pressure medium split from the branch can neutralize the heat of the low-superheated medium (i.e., the liquid refrigerant) output by the evaporator when it is running near the freezing point. Then, the medium is heated by a heater, thus preventing the high-temperature, low-pressure medium output by the evaporator from entering the compressor in a low-superheated or even liquid-laden state, which would have adverse effects. This ensures that the evaporator can operate in the second operating state for a long time without affecting the normal operation of the system. In the second operating state, the flow rate of the medium entering the evaporator can be flexibly adjusted by controlling the opening of the branch, so as to accurately test the evaporator.

[0031] (3) The evaporator auxiliary module can meet the testing requirements of various evaporators by switching between the first working state and the second working state. During the evaporator freezing test, it realizes the state isolation between the evaporator output medium and the compressor input medium, thereby ensuring the working safety of the compressor.

[0032] (4) In this invention, most of the pipes and devices in the evaporator freezing test bench are integrated on the evaporator auxiliary module. When the evaporator is frozen, only the vapor-liquid separator, compressor and condenser need to be connected to the evaporator auxiliary module to form the above-mentioned evaporator freezing test bench, which is convenient, fast and widely applicable.

[0033] (5) The present invention also proposes an evaporator freezing test bench. By using the above-mentioned evaporator auxiliary module, the state isolation between the evaporator output medium and the compressor input medium can be achieved during the test, thereby ensuring the working safety of the compressor.

[0034] (6) An evaporator water tank is provided in this invention so that the evaporator can be placed in the evaporator water tank to improve the heat exchange efficiency of the evaporator. The stirring device in the evaporator water tank is used to improve the heat exchange efficiency in the evaporator water tank. The stirring device is driven by the prime mover of the compressor, so there is no need to add an additional power source for the stirring device, which can greatly save energy and reduce emissions.

[0035] (7) In this invention, a control module is provided, which can realize real-time monitoring of the medium state and switching of the working state of the test bench, which is conducive to achieving efficient and convenient evaporator freezing test.

[0036] (8) In this invention, an open-type compressor is used, which further avoids the possibility of the compressor being damaged by liquid slugging.

[0037] (9) In this invention, the stirring device is driven by the prime mover of the open compressor to stir the evaporator water tank, which improves the power utilization efficiency, simplifies the construction cost of the evaporator freezing test bench, and helps to improve the evaporation efficiency of the evaporator and improve the heat exchange effect on the medium. Attached Figure Description

[0038] Figure 1 This is a structural diagram of an evaporator freezing test bench;

[0039] Figure 2 for Figure 1 The diagram shows an existing evaporator test circuit included in the evaporator freezing test bench.

[0040] Figure 3 for Figure 1 The diagram shows the medium flow direction under the first working state of the evaporator freezing test bench.

[0041] Figure 4 for Figure 1 The diagram shows the medium flow direction under the second working state of the evaporator freezing test bench;

[0042] Figure 5 This is a schematic diagram of an evaporator auxiliary module;

[0043] Figure 6 This is a schematic diagram of another type of evaporator auxiliary module.

[0044] Diagram: 10. Evaporator inlet connection branch; 11. Second regulating valve; 12. Fourth valve; 20. Evaporator outlet connection branch; 21. Fifth valve; 30. Condenser connection branch; 40. Branch line; 41. First regulating valve; 42. Third valve;

[0045] 1. First valve; 2. Second valve; 3. Heater; 4. Condenser; 5. Vapor-liquid separator; 6. Compressor; 7. Hot gas bypass valve; 100. Evaporator;

[0046] a1, First temperature sensor; a2, Second temperature sensor; a3, Third temperature sensor; a4, Fourth temperature sensor; a5, Fifth temperature sensor;

[0047] b1, First pressure sensor; b2, Second pressure sensor; b3, Third pressure sensor; b4, Fourth pressure sensor; b5, Fifth pressure sensor; Detailed Implementation

[0048] An evaporator freezing test bench

[0049] like Figure 1 As shown, the evaporator freezing test bench proposed in this embodiment includes: an evaporator inlet connection branch 10, an evaporator outlet connection branch 20, a diversion branch 40, a first valve 1, a second valve 2, a heater 3, a condenser 4, a vapor-liquid separator 5, a compressor 6, and a hot gas bypass valve 7.

[0050] The first end of the evaporator inlet connection branch 10 is used to connect to the input end of the evaporator; the first end of the branch 40 is connected to the output end of the condenser 4 and the second end of the evaporator inlet connection branch 10 respectively, and the second end of the branch 40 is connected to the input end of the heater 3; a first regulating valve 41 is provided on the branch 40.

[0051] The first end of the evaporator output port connection branch 20 is used to connect to the output end of the evaporator; the two ends of the first valve 1 are respectively connected to the second end of the evaporator output port connection branch 20 and the input end of the heater 3; the two ends of the second valve 2 are respectively connected to the second end of the evaporator output port connection branch 20 and the output end of the heater 3.

[0052] The output of compressor 6 is connected to the input of condenser 4. The output of heater 3 is connected to the input of vapor-liquid separator 5, and the output of vapor-liquid separator 5 is connected to the input of compressor 6. The two ends of hot gas bypass valve 7 are connected to the output of heater 3 and the output of compressor 6, respectively. Thus, when the medium output from heater 3 is diverted through hot gas bypass valve 7, the state of the medium input to condenser 4 can be adjusted by mixing the medium passing through hot gas bypass valve 7 with the medium output from compressor 6. When the suction volume at the input of compressor 6 is insufficient, the medium output from compressor 6 can also be diverted back to the input of compressor 6 through hot gas bypass valve 7 to ensure the suction volume of compressor 6.

[0053] Thus, in this embodiment, when the first valve 1 is open and the heater 3 is working, the medium output from the evaporator 100 can flow to the vapor-liquid separator 5 through the heater 3. The heater 3 can further heat the medium output from the evaporator 100, so that when the heat exchange efficiency of the evaporator 100 is low, the liquid refrigerant that may be contained in the medium output from the evaporator 100 can be further heated by the heater 3 to ensure the full vaporization of the refrigerant, thereby avoiding liquid slugging in the compressor 6.

[0054] When the first valve 1 is closed, the medium output from the condenser 4 can be divided into two paths through the parallel connection of the diversion branch 40 and the evaporator inlet connection branch 10. One path of medium passes through the evaporator 100 and the second valve 2 to the output end of the heater 3, and the other path of medium passes through the diversion branch 40 and the heater 3 in operation to the output end of the heater 3. The two paths of medium are mixed at the output end of the heater 3 and then enter the vapor-liquid separator.

[0055] The first working state of the evaporator freezing test bench is when the first valve 1 is closed, the branch line 40 is unobstructed, and the heater 3 is turned on. The second working state is when the first valve 1 is unobstructed, the branch line 40 is unobstructed, and the heater 3 is turned on.

[0056] In this embodiment, when the first valve 1 is closed and the second valve 2 and the third valve 42 are open, the first working state is achieved. At this time, the evaporator inlet connection branch 10, the evaporator 100, the evaporator outlet connection branch 20, and the second valve 2 are connected in series to form one flow channel, and the branch branch 40 and the heater 3 are connected in series to form another flow channel. These two flow channels are connected in parallel. In this way, the low-temperature, high-pressure medium diverted from the branch branch 40 can neutralize the heat of the high-temperature, low-pressure medium output from the evaporator 100, thereby avoiding the adverse effects of the high-temperature, low-pressure medium output from the evaporator 100 entering the compressor 6 under an overheated state. Through the first regulating valve 41 and the second regulating valve 11, the flow ratio of the flow channel where the evaporator 100 is located and the flow channel where the branch branch 40 is located can be controlled in the first working state, thereby achieving flexible adjustment of the superheat of the medium.

[0057] In the second operating state, the low-temperature, high-pressure medium output from condenser 4 flows through condenser connecting branch 30 and splits into two paths. The first path flows through evaporator inlet connecting branch 10, evaporator 100, evaporator outlet connecting branch 20, and first valve 1. The second path flows through branch 40 and mixes with the first path flowing through first valve 1 before entering heater 3. The mixed medium is heated by heater 3 and then flows into vapor-liquid separator 5. The second operating state is suitable for testing the freezing point of evaporation. By controlling the opening of branch 40, the flow rate of refrigerant entering the evaporator can be flexibly controlled. The medium flowing through evaporator 100 and the medium flowing out of branch 40 are both heated by heater 3 before entering vapor-liquid separator 5. Heater 3 provides heat to the medium, preventing the low-superheated refrigerant output from evaporator 3 from adversely affecting the compressor, such as liquid slugging.

[0058] In this embodiment, a second regulating valve 11 is also provided on the evaporator inlet connection branch 10, and a third valve 42 is also provided on the diversion branch 40. Thus, the switching between the first operating state and the second operating state can be controlled by the first valve 1, the second valve 2, and the third valve 42.

[0059] Specifically, in this embodiment, when the first valve 1 is open and the third valve 42 is closed, the flow branch 40 is interrupted, and the low-temperature, high-pressure output from the condenser 4 completely passes through the evaporator 100. If the superheat of the high-temperature, low-pressure medium output from the evaporator 100 is insufficient, the medium can be further heated by the heater 3 to increase the superheat. If the superheat of the high-temperature, low-pressure medium output from the evaporator 100 reaches a threshold value, such as 3 degrees Celsius, the second valve 2 can be opened, allowing the high-temperature, low-pressure medium output from the evaporator 100 to reach the output end of the heater 3 through the second valve 2, thus entering the subsequent process. In this way, further heating of the medium by the heater 3 is avoided, and the strong resistance phenomenon when the gaseous high-temperature, low-pressure medium passes through the non-operating heater 3 is also avoided. In the first operating state, i.e., when both the first valve 1 and the third valve 42 are open, the temperature of the medium output from the flow branch 40 can also be flexibly adjusted by the heater 3, thereby adjusting the temperature of the medium entering the vapor-liquid separator 5.

[0060] Based on existing technology, the superheat of the medium output by evaporator 100 can be calculated based on the temperature and pressure of the output medium.

[0061] In this embodiment, a fourth valve 12 is also provided on the evaporator inlet connection branch 10, and a fifth valve 21 is also provided on the evaporator outlet connection branch 20. The fourth valve 12 and the fifth valve 21 are provided to control whether the evaporator 100 is connected or not.

[0062] In this embodiment, a first temperature sensor a1 and a first pressure sensor b1 are provided on the evaporator inlet connection branch 10, and a second temperature sensor a2 and a second pressure sensor b2 are provided on the evaporator outlet connection branch 20. The first temperature sensor a1 and the first pressure sensor b1 are located on the side of the second regulating valve 11 facing the first end of the evaporator inlet connection branch 10. Thus, by comparing the data from the first temperature sensor a1 and the second temperature sensor a2, the temperature change of the medium before and after passing through the evaporator 100 can be determined; by comparing the data from the first pressure sensor b1 and the second pressure sensor b2, the pressure change of the medium before and after passing through the evaporator 100 can be determined. Therefore, by combining the temperature difference between the detection values ​​of the first temperature sensor a1 and the second temperature sensor a2, and the pressure difference between the detection values ​​of the first pressure sensor b1 and the second pressure sensor b2, the performance of the evaporator 100 can be determined.

[0063] Furthermore, by setting the first and second working states, the evaporator freezing test bench can be applied to various evaporators 100 with different performance characteristics, and ensures the safety of the compressor 6, avoiding frequent failure of the compressor 6 during the test.

[0064] In this embodiment, a third temperature sensor a3 and a third pressure sensor b3 are also provided on the evaporator inlet connection branch 10, located at its second end between the second regulating valve 11. Thus, by comparing the data from the first temperature sensor a1 and the third temperature sensor a3, the temperature change of the medium before and after passing through the second regulating valve 11 can be determined; similarly, by comparing the data from the first pressure sensor b1 and the third pressure sensor b3, the pressure change of the medium before and after passing through the second regulating valve 11 can be determined.

[0065] In this embodiment, to ensure global monitoring of the evaporator freezing test bench and real-time monitoring of changes in the medium's state during the test, a fourth pressure sensor b4 can be installed at the output end of the compressor 6, and a fifth temperature sensor a5 and a fifth pressure sensor b5 can be installed at the input end of the compressor 6. Thus, by comparing the data from the fourth pressure sensor b4 and the fifth pressure sensor b5, the compression effect of the compressor 6 on the refrigerant medium can be directly obtained; and by monitoring the temperature of the refrigerant returning to the compressor 6 in real time through the fifth temperature sensor a5, it is helpful to determine whether the refrigerant returning to the compressor 6 is in a superheated state and whether it contains liquid refrigerant, thereby avoiding liquid slugging in the compressor 6.

[0066] In this embodiment, the compressor 6 is an open-type compressor, also known as an open compressor or open-type compressor, in order to reduce the damage of liquid slugging to the compressor 6.

[0067] The evaporator freezing test bench in this embodiment also includes an evaporator water tank, which is equipped with a stirring device. The stirring device is connected to the prime mover of the compressor 6 to obtain driving force. Thus, by stirring the water in the evaporator water tank, the evaporation efficiency of the evaporator 100 is improved, and the heat exchange effect on the medium is enhanced. Furthermore, since the stirring device is driven by the prime mover of the compressor 6, the power utilization efficiency is improved, and the construction cost of the evaporator freezing test bench is simplified.

[0068] The evaporator freezing test bench in this embodiment also includes a control module and a fourth temperature sensor a4 installed on the condenser connection branch 30. The control module is connected to the second temperature sensor a2, the second pressure sensor b2, the fourth temperature sensor a4, the first valve 1, the second valve 2, the first regulating valve 41, the second regulating valve 11, and the heater 3, respectively. The control module is used to adjust the working states of the first valve 1, the second valve 2, the first regulating valve 41, the second regulating valve 11, and the heater 3 according to the detection values ​​of the second temperature sensor a2, the second pressure sensor b2, and the fourth temperature sensor a4, so as to switch between the first working state and the second working state.

[0069] A method for testing the freezing of evaporators

[0070] The evaporator freezing test method uses the aforementioned evaporator freezing test bench. During the test, the aforementioned evaporator freezing test bench is first set up, and the stirring device is turned on.

[0071] The following steps are taken when testing the evaporator 100:

[0072] Step 1: First, turn on compressor 6, condensers 4, 41, 42, evaporator 100, fourth valve 12, and second valve 2, and close first valve 1 and third valve 42. The medium flow direction is as follows: Figure 2 As shown.

[0073] Step 2: During the operation of compressor 6, the superheat of the input medium of compressor 6 is calculated by using the temperature detected by the fifth temperature sensor a5 and the pressure detected by the fifth pressure sensor.

[0074] Step 3: When the superheat of the input medium to compressor 6 is within the range [3°-Δf, 3°+Δf] as in Step 2, the operating state of Step 1 is maintained, and the parameters of evaporator 100 are calculated based on the detection data of the first temperature sensor a1, the second temperature sensor a2, the first pressure sensor b1, and the second pressure sensor b2. Δf is a preset float value, Δf≥0.

[0075] Step 3: If the superheat of the medium input to compressor 6 in step 2 is greater than 3° + Δf, it indicates that the medium output from evaporator 100 is overheated. At this time, control the first valve 1 to close and the third valve 42 to open, to achieve the first working state. The medium flow direction is as follows: Figure 3 As shown. At this time, the branch line 40 is unobstructed, and the low-temperature, high-pressure medium output from the condenser 4 is divided into two paths. One path flows through the condenser connection branch 30, the evaporator inlet connection branch 10, the evaporator 100, the evaporator outlet connection branch 20, and the second valve 2. The other path flows through the branch line 40 to the output end of the heater 3 and mixes with the other path of medium passing through the second valve 2 before flowing into the vapor-liquid separator 5. In this way, mixing the medium output from the evaporator 100 with another part of the medium that has not passed through the evaporator 100 can reduce the superheat of the evaporator 100, thereby ensuring the normal operation of the compressor 6. At this time, the working efficiency of the heater 3 can be flexibly adjusted to adjust the temperature of the medium passing through the branch line 40, thereby controlling the temperature of the medium at the input end of the vapor-liquid separator 5 by mixing the two paths of medium at the output end of the heater 3.

[0076] Step 4: If the superheat of the input medium to compressor 6 is less than 3°-Δf in step 2, then open the first valve 1 and close the second valve 2 to achieve the second working state. The medium flow direction is as follows: Figure 4As shown, the low-temperature, high-pressure medium output from condenser 4 is divided into two streams via condenser connection branch 30. One stream flows through evaporator inlet connection branch 10, evaporator 100, evaporator outlet connection branch 20, and the first valve 1 before entering heater 3. The other stream flows through branch 40 into heater 3. Heater 3 heats the incoming medium before outputting it to vapor-liquid separator 5. By using heater 3 to compensate for the temperature of the medium output from evaporator 100, the gaseous input of the compressor is guaranteed without affecting the testing accuracy of evaporator 100, thus ensuring the normal operation of the compressor during the test and preventing liquid slugging.

[0077] In this embodiment, the freezing test of the evaporator 100 is performed by calculating the parameters of the evaporator 100 based on the detection data of the first temperature sensor a1, the second temperature sensor a2, the first pressure sensor b1, and the second pressure sensor b2. The performance data of the evaporator 100 can then be obtained. This calculation process is existing technology and will not be described in detail here.

[0078] In step three above, the superheat of the medium output by the evaporator 100 can be calculated based on the detection values ​​of the second temperature sensor a2 and the second pressure sensor b2, and the superheat of the medium input by the compressor 6 can be calculated based on the detection values ​​of the fifth temperature sensor a5 and the fifth pressure sensor b5. Then, based on the difference between the superheat of the medium output by the evaporator 100 and the superheat of the medium input by the compressor 6, the first regulating valve 41 and the second regulating valve 11 are adjusted, thereby adjusting the flow ratio on the two parallel pipelines of the evaporator 100 and the branch line 40, so as to adjust the superheat of the medium input by the compressor 6.

[0079] In step four, the superheat of the medium output by the evaporator 100 can be calculated based on the detection values ​​of the second temperature sensor a2 and the second pressure sensor b2, and the superheat of the medium input by the compressor 6 can be calculated based on the detection values ​​of the fifth temperature sensor a5 and the fifth pressure sensor b5. Then, based on the difference between the superheat of the medium output by the evaporator 100 and the superheat of the medium input by the compressor 6, the working power or working time of the heater 3 can be adjusted to adjust the superheat of the medium input by the compressor 6.

[0080] In this embodiment, the key issue to be addressed is how to ensure the safe operation of the compressor 6 during the freezing test of the evaporator 100.

[0081] Based on the above-described evaporator freezing test bench, it is clear that the switching between its first and second operating states is crucial to ensuring the normal operation of the compressor 6. This switching primarily involves the evaporator inlet connection branch 10, the evaporator outlet connection branch 20, the branch line 40, the first valve 1, the second valve 2, and the heater 3. Therefore, by integrating the aforementioned evaporator inlet connection branch 10, evaporator outlet connection branch 20, branch line 40, first valve 1, second valve 2, and heater 3, an evaporator auxiliary module can be implemented. During the evaporator freezing test, simply connecting the vapor-liquid separator 5, the compressor 6, and the condenser 4 to this evaporator auxiliary module constitutes the aforementioned evaporator freezing test bench.

[0082] An evaporator auxiliary module

[0083] like Figure 5 As shown, the evaporator auxiliary module provided in this embodiment includes: an evaporator inlet connection branch 10, an evaporator outlet connection branch 20, a condenser connection branch 30, a flow branch 40, a first valve 1, a second valve 2, and a heater 3.

[0084] The first end of the condenser connection branch 30 is used to connect to the output end of the condenser, and the first end of the evaporator inlet connection branch 10 is used to connect to the input end of the evaporator; the first end of the branch 40 is connected to the second end of the condenser connection branch 30 and the second end of the evaporator inlet connection branch 10 respectively, and the second end of the branch 40 is connected to the input end of the heater 3; a first regulating valve 41 is provided on the branch 40.

[0085] The first end of the evaporator output port connection branch 20 is used to connect to the output end of the evaporator; the two ends of the first valve 1 are respectively connected to the second end of the evaporator output port connection branch 20 and the input end of the heater 3; the two ends of the second valve 2 are respectively connected to the second end of the evaporator output port connection branch 20 and the output end of the heater 3.

[0086] It is worth noting that the condenser connection branch 30 is not described in the aforementioned evaporator freezing test bench. However, the aforementioned evaporator freezing test bench describes the connection between the output end of the condenser 4 and the first end of the branch 40. The condenser connection branch 30 here is an auxiliary component used to connect the output end of the condenser 4 to the first end of the branch 40. The condenser connection branch 30 is introduced into this evaporator auxiliary module to facilitate the explanation of the connection of the condenser 4. Although the aforementioned evaporator freezing test bench does not describe the condenser connection branch 30, it is evident from the piping connections that the condenser connection branch 30 is actually present; this should be understood by those skilled in the art.

[0087] The evaporator auxiliary module has two operating states. In the first operating state, the evaporator auxiliary module is implemented as two channels connected in parallel between the second end of the condenser connection branch and the output end of the heater 3. The evaporator 100 is located on one channel, and the branch 40 is located on the other. Specifically, in this state, the low-temperature, high-pressure medium output from the condenser 4 is split into two. One channel is evaporated into a high-temperature, low-pressure medium by the evaporator 100, while the other channel remains in a low-temperature, high-pressure state. The two channels converge at the output end of the heater 3, achieving the mixing of the high-temperature, low-pressure medium output from the evaporator 100 and the low-temperature, high-pressure medium diverted from the condenser 4 through the branch 40. This allows for heat neutralization when the high-temperature, low-pressure medium output from the evaporator 100 is overheated, ensuring the safe operation of subsequent processes. The temperature of the medium passing through the branch 40 can be flexibly adjusted by the heater 3 to control the temperature of the mixed medium at the output end of the heater 3.

[0088] In the second operating state, the second valve 2 is closed. The medium passing through the evaporator 100 and the medium passing through the branch circuit mix at the input end of the heater 3 and then flow into the heater 3. At this time, if the superheat of the medium output from the evaporator 100 is less than the threshold, the medium can be heated by the heater 3 to ensure that the medium is fully vaporized before entering the subsequent process. The second operating state is applicable to the evaporator 100 operating near the freezing point, that is, it is applicable to the freezing point test of the evaporator.

[0089] The high-temperature, low-pressure medium output from the evaporator 100 includes a gaseous state. The gaseous medium entering the heater 3 may encounter strong resistance, leading to uncertainty in the test results. In this embodiment, by setting a first valve 1 and a second valve 2, the high-temperature, low-pressure medium output from the evaporator 100 flows through the second valve 2 to bypass the heater 3 during the first operating state, ensuring the safety and stability of the test.

[0090] Since the low-temperature, high-pressure medium output from condenser 4 is usually liquid, the low-temperature, high-pressure medium diverted through branch 40 can directly reach the output end of heater 3, thus simplifying the piping structure. Similarly, since evaporator 100 operates near the freezing point, the medium output from evaporator 4 is in a low-superheat state. At this time, the medium output from evaporator 100 mixes with the medium passing through branch 40 to form a liquid medium, which can then directly enter heater 3.

[0091] In this embodiment, in order to facilitate the switching between the first working state and the second working state, valves can be installed on the evaporator inlet connection branch 10 and the branch branch 40 for easy adjustment.

[0092] Specifically, in this embodiment, a first regulating valve 41 is provided on the branch line 40, and a second regulating valve 11 is provided on the branch line 10 connecting to the evaporator inlet. In the first and second working states, by adjusting the first regulating valve 41 and the second regulating valve 11, the ratio of the medium output from the condenser 4 flowing through the evaporator 100 and the branch line 40 can be controlled, thereby flexibly adjusting the superheat of the medium mixed at the output end of the heater 3.

[0093] In this embodiment, a third valve 42 is provided on the branch line 40, and a fourth valve 12 is provided on the branch line 10 connecting the evaporator inlet. The third valve 42 can control the opening and closing of the branch line 40, and the fourth valve 12 can control the opening and closing of the branch line 10 connecting the evaporator inlet.

[0094] Specifically, in this embodiment, in order to further improve the integration of the evaporator auxiliary module, a first temperature sensor a1 and a first pressure sensor b1 are provided on the evaporator inlet connection branch 10, and a second temperature sensor a2 and a second pressure sensor b2 are provided on the evaporator inlet connection branch 10. The first temperature sensor a1 and the first pressure sensor b1 are located at the end of the second regulating valve 11 facing the evaporator 100, so as to calculate the performance parameters of the evaporator 100 based on the comparison of the data of the first temperature sensor a1 and the second temperature sensor a2 and the comparison of the data of the first pressure sensor b1 and the second pressure sensor b2.

[0095] In this embodiment, a third temperature sensor a3 and a third pressure sensor b3 are provided on the side of the second regulating valve 11 facing the diversion branch 40 on the evaporator inlet connection branch 10, and a fourth temperature sensor a4 is provided on the condenser connection branch 30.

[0096] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for testing the freezing of an evaporator, characterized in that, Evaporator freezing test is conducted using an evaporator freezing test bench, which includes: evaporator inlet connection branch (10), evaporator outlet connection branch (20), branch branch (40), first valve (1), second valve (2), heater (3), condenser (4), vapor-liquid separator (5), compressor (6) and hot gas bypass valve (7). The first end of the condenser connection branch (30) is used to connect to the output end of the condenser (4), and the first end of the evaporator inlet connection branch (10) is used to connect to the input end of the evaporator; the first end of the branch (40) is connected to the second end of the condenser connection branch (30) and the second end of the evaporator inlet connection branch (10) respectively, and the second end of the branch (40) is connected to the input end of the heater (3); a first regulating valve (41) is provided on the branch (40); a second regulating valve (11) is also provided on the evaporator inlet connection branch (10). The first end of the evaporator output port connection branch (20) is used to connect to the output end of the evaporator; the two ends of the first valve (1) are respectively connected to the second end of the evaporator output port connection branch (20) and the input end of the heater (3); the two ends of the second valve (2) are respectively connected to the second end of the evaporator output port connection branch (20) and the output end of the heater (3); The output end of the compressor (6) is connected to the input end of the condenser (4); the output end of the heater (3) is connected to the input end of the vapor-liquid separator (5), and the output end of the vapor-liquid separator (5) is connected to the input end of the compressor (6); the two ends of the hot gas bypass valve (7) are respectively connected to the output end of the heater (3) and the output end of the compressor (6); the input end of the compressor (6) is also equipped with a fifth pressure sensor (b5). A third valve (42) is provided on the branch line (40); a first temperature sensor (a1) and a first pressure sensor (b1) are provided on the evaporator inlet connection branch line (10); a second temperature sensor (a2) and a second pressure sensor (b2) are provided on the evaporator outlet connection branch line (20); a fourth valve (12) is provided on the evaporator inlet connection branch line (10); a fifth temperature sensor (a5) is provided at the input end of the compressor (6). The evaporator freezing test bench has two working states. The first working state is when the first valve (1) is closed, the branch line (40) is unobstructed and the heater (3) is turned on. The second working state is when the first valve (1) is unobstructed, the branch line (40) is unobstructed and the heater (3) is turned on. The first temperature sensor (a1) and the first pressure sensor (b1) are located on the side of the second regulating valve (11) facing the first end of the evaporator inlet connection branch (10); A third temperature sensor (a3) ​​and a third pressure sensor (b3) are also provided on the evaporator inlet connection branch (10) between its second end and the second regulating valve (11). A fifth valve (21) is also provided on the evaporator output port connection branch (20); the fourth valve (12) and the fifth valve (21) are used to control whether the evaporator (100) is connected or not; The steps for testing the evaporator (100) are as follows: Step 1: First turn on the compressor (6), condenser (4), first regulating valve (41), third valve (42), evaporator (100), fourth valve (12) and second valve (2), and then turn off the first valve (1) and the third valve (42). Step 2: During the operation of the compressor (6), the superheat of the input medium of the compressor (6) is calculated by the temperature detected by the fifth temperature sensor (a5) and the pressure detected by the fifth pressure sensor; Step 3: When the superheat of the input medium of the compressor (6) is in the range of Step 2, When the above is true, the working state of step one is maintained, and the parameters of the evaporator (100) are calculated by combining the detection data of the first temperature sensor (a1), the second temperature sensor (a2), the first pressure sensor (b1), and the second pressure sensor (b2); To preset the float value, ; Step 3: When the superheat of the input medium to the compressor (6) is greater than that in step 2, This indicates that the medium output by the evaporator (100) is overheated. At this time, the first valve (1) is shut off and the third valve (42) is opened to achieve the first working state. Step 4: When the superheat of the input medium to the compressor (6) is less than in Step 2... Then the first valve (1) is opened and the second valve (2) is closed to achieve the second working state.

2. The evaporator freezing test method as described in claim 1, characterized in that, In step three above, the superheat of the medium output by the evaporator (100) is calculated based on the detection values ​​of the second temperature sensor (a2) and the second pressure sensor (b2). The superheat of the medium input by the compressor (6) is calculated based on the detection values ​​of the fifth temperature sensor (a5) and the fifth pressure sensor (b5). Then, based on the difference between the superheat of the medium output by the evaporator (100) and the superheat of the medium input by the compressor (6), the first regulating valve (41) and the second regulating valve (11) are adjusted, thereby adjusting the flow ratio on the two parallel pipelines of the evaporator (100) and the branch line (40) to adjust the superheat of the medium input by the compressor (6).

3. The evaporator freezing test method as described in claim 1, characterized in that, In step four, the superheat of the medium output by the evaporator (100) is calculated based on the detection values ​​of the second temperature sensor (a2) and the second pressure sensor (b2). The superheat of the medium input by the compressor (6) is calculated based on the detection values ​​of the fifth temperature sensor (a5) and the fifth pressure sensor (b5). Then, based on the difference between the superheat of the medium output by the evaporator (100) and the superheat of the medium input by the compressor (6), the working power or working time of the heater (3) is adjusted to adjust the superheat of the medium input by the compressor (6).

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