WO2023115552A1 - Performance test method and system for refrigeration compressor - Google Patents

Abstract

A performance test method for a refrigeration compressor, wherein a refrigerant output by a compressor (1) is divided into two parts after cooling, one part is converted into a low-pressure gaseous refrigerant, and the other part is subjected to a condensation treatment; and the gaseous refrigerant and the condensed refrigerant are mixed and then input into the compressor (1) to form a refrigerant circulation loop. By means of the performance test method for a refrigeration compressor, by first cooling and then dividing the refrigerant output by the compressor, the temperature of the refrigerant in the gaseous form is relatively low, such that same can exchange heat with the condensed refrigerant in a relatively small space, thus reducing the occupied area of a test system, decreasing the temperature difference between the two parts of the refrigerant before same enter the mixed state, which are beneficial for accurately controlling the gas-liquid ratio after the two parts of the refrigerant are mixed, thereby further improving the test precision of the compressor.

Description

A method and system for testing the performance of a refrigeration compressor technical field

The invention relates to the field of compressors, in particular to a performance testing method and system for a refrigeration compressor.

Background technique

With the use of air conditioners more and more widely, the performance and energy-saving effect of various air conditioners have attracted more and more attention. Therefore, it is particularly important to test the performance of air conditioners, and the compressor test device for air conditioner performance tests is the most important Heavy. At present, the refrigerant vapor flowing out from the gas cooler of the test device should undergo gas-liquid separation, without liquid droplets, and with a superheat of above 8°C to ensure the normal operation of the refrigeration system.

Traditional positive displacement compressor test setups usually use the refrigerant gas cooling method. The working principle of the system where the compressor is located is: the refrigerant is compressed and discharged by the compressor, a part of the refrigerant is throttled and depressurized by the gas throttle valve, and the remaining part is condensed into liquid by the condenser, and then throttled and depressurized by the liquid throttle valve. The two refrigerants are mixed at the gas cooler. At this time, the ratio of the condensed refrigerant mass and the uncondensed refrigerant mass entering the gas cooler is the reciprocal of the specific enthalpy of the two vapors in the gas cooler. In the traditional gas cooling method, there are many liquids in the gas cooler, and a large space is required for the phase change during mixing. Therefore, the traditional gas cooler has a large volume, complex structure, and is difficult to control, which reduces the test accuracy and efficiency of the refrigeration system.

Contents of the invention

In order to solve the defects in the prior art that the refrigeration system test gas cooler is large in size and difficult to control, and the refrigeration system test accuracy is low, the present invention proposes a performance test method and system for refrigeration compressors.

One of purpose of the present invention adopts following technical scheme:

A refrigeration compressor performance testing system, including: a pre-condensing part, a decompression part, a recondensing part, a gas-liquid mixing part and a monitoring part;

The output end of the pre-condensation part is respectively connected to the input end of the step-down part and the input end of the re-condensation part; the output end of the step-down part and the output end of the re-condensation part are both connected to the input end of the gas-liquid mixing part, and the The output end and the input end of the pre-condensing part constitute a test interface for connecting to the compressor, wherein the output end of the gas-liquid mixing part is used to connect to the input end of the compressor, and the input end of the pre-condensing part is used to connect to the compressor's output terminal;

The pre-condensing part is used to cool down the refrigerant output by the compressor; the refrigerant output by the pre-condensing part is divided into two parts, one part is converted into a low-pressure gas state through the decompression part, and the other part is condensed through the re-condensing part; The output low-pressure gaseous refrigerant and the low-temperature liquid refrigerant output from the recondensing part are mixed through the gas-liquid mixing part and then flow back to the input end of the compressor; the ratio of the refrigerant flowing through the decompression part to the refrigerant flowing through the recondensing part is adjustable ;

The monitoring part is used to detect the temperature and pressure of the refrigerant in the refrigerant circulation circuit composed of the pre-condensing part, the decompression part, the re-condensing part, the gas-liquid mixing part and the compressor.

Preferably, the gas-liquid mixing part includes a gas cooler and a return pipe, the gas cooler is provided with a gas inlet, a liquid inlet and a return port, the gas inlet is connected to the output end of the decompression part, and the liquid inlet is connected to the recondensation The output end of the part is connected, the return port is connected with the first end of the return pipe, and the second end of the return pipe is used as the output end of the vapor-liquid mixing part.

Preferably, the recondensing part includes a second condenser and a flow regulating valve, the flow regulating valve is arranged on the pipeline used to connect the input end of the second condenser and the output end of the precondensing part, and the output end of the second condenser The liquid inlet is connected by tubing.

Preferably, the depressurization part includes a gas throttling valve, and the gas throttling valve is arranged on the pipeline for connecting the output end of the pre-condensing part and the gas inlet; for connecting the output end of the second condenser and the The pipeline of the liquid inlet is provided with a liquid throttling valve.

Preferably, a gas-liquid separator is further provided between the return port and the input end of the compressor.

Preferably, the gas cooler adopts a T-shaped tube or a cylinder with both ends sealed;

When the gas cooler adopts a T-shaped tube, its three ports are respectively used as gas inlet, liquid inlet and return port;

When the gas cooler adopts a cylinder with both ends sealed, the liquid inlet is arranged at the lower part of the cylinder, the gas inlet is arranged at the middle of the cylinder, and the return port is arranged at the upper part of the cylinder.

Preferably, the pipeline connected to the liquid inlet and used to input the refrigerant passing through the recondensing part into the gas cooler is designated as a liquid inlet pipe, which is connected to the gas inlet and used to input the refrigerant passing through the decompression part The pipeline of the gas cooler is recorded as the inlet pipe, and the pipeline connected with the return port for the refrigerant in the output gas cooler is recorded as the gas outlet pipe; the inner diameter of the liquid inlet pipe, the inner diameter of the inlet pipe and the pipe of the outlet pipe The inner diameters are recorded as d ₅ , d ₂ and d ₁ respectively;

When the gas cooler adopts a T-shaped tube, the inner diameter of the T-shaped tube is 3 to 5 times the inner diameter of the air outlet pipe, and the length of the T-shaped pipe is 8 to 12 times the inner diameter of the air outlet pipe;

When the gas cooler adopts a cylinder with both ends sealed, the height of the cylinder is 1.5 to 3 times the inner diameter _d3 of the cylinder, and:

d ₂ /d ₅ =[(h ₁ -h ₅ )v ₂ /(h ₂ -h ₁ )v ₅ ] ^0.5 ;

d ₂ /d ₅ =[(h ₁ -h ₅ )v ₂ /(h ₂ -h ₁ )v ₅ ] ^0.5 ;

d ₁ =1.2d ₅ [(h ₂ -h ₁ )v ₁ /(h ₂ -h ₅ )v ₅ ] ^0.5 ;

Among them, h ₁ is the inlet enthalpy of the compressor, h ₂ is the outlet enthalpy of the compressor, h ₅ is the enthalpy of the outlet of the liquid throttle valve; v ₁ is the specific volume of the gas refrigerant input into the compressor 1, v ₂ is the specific volume of the liquid refrigerant output from the compressor 1, v ₅ is the specific volume of the refrigerant output from the recondenser to the gas cooler.

Preferably, the monitoring part includes a first temperature and pressure sensor, a second temperature and pressure sensor, a third temperature and pressure sensor and a fourth temperature and pressure sensor; the first temperature and pressure sensor is used to detect the temperature and pressure of the refrigerant input into the first condenser , the second temperature and pressure sensor is used to detect the temperature and pressure of the refrigerant output from the first condenser, the third temperature and pressure sensor is used to detect the temperature and pressure of the refrigerant mixed in the gas-liquid mixing part, and the fourth temperature and pressure Sensors are used to detect the temperature and pressure of the refrigerant fed into the compressor.

Two of the purpose of the present invention adopts following technical scheme:

A method for testing the performance of a refrigeration compressor, comprising the following steps:

S1. The refrigerant output by the compressor is cooled and divided into two parts, one part is converted into low-pressure gaseous refrigerant, and the other part is condensed;

S2. Mix the above-mentioned low-pressure gaseous refrigerant and the condensed refrigerant into the compressor to form a refrigerant circulation loop;

S3. Evaluate the performance of the compressor according to the temperature and pressure changes of the refrigerant in the refrigerant circulation loop.

Preferably, the temperature and pressure of the refrigerant output by the compressor are respectively recorded as the first temperature and the first pressure, and the cooled temperature and pressure of the refrigerant output by the compressor are respectively recorded as the second temperature and the second pressure; The temperature and pressure at which the gaseous refrigerant and the condensed refrigerant are mixed are respectively recorded as the third temperature and the third pressure, and the temperature and pressure of the refrigerant input into the compressor are respectively recorded as the fourth temperature and the fourth pressure; In step S3, the performance of the compressor is evaluated according to the first temperature, the second temperature, the third temperature, the fourth temperature, the first pressure, the second pressure, the third pressure and the fourth pressure.

The advantages of the present invention are:

1), the present invention proposes a performance test system for refrigeration compressors. After the compressor, a pre-condensing part, that is, a first condenser is added. The temperature at which the agent enters the second condenser and the decompression section. Because the ratio of the condensed refrigerant mass to the uncondensed refrigerant mass in the air-pressure mixing part is the reciprocal of the specific enthalpy of the two refrigerants entering the gas-liquid mixing part. Therefore, the temperature adjustment of the refrigerant by the first condenser also indirectly controls the gas-liquid ratio in the gas-liquid mixing part, which is beneficial to ensure the sufficient mixing of refrigerant gas and liquid, thereby avoiding the instability of superheat and suction The problem of temperature fluctuation improves the test accuracy; at the same time, it also reduces the demand for the heat exchange space of the two refrigerants, which is conducive to reducing the footprint of the test system.

2) In this system, the setting of the gas throttle valve realizes the interception of the refrigerant flowing through the gas throttle valve, thereby reducing the pressure of the refrigerant at the output end of the gas throttle valve. The setting of the liquid throttling valve is beneficial to control the amount of low-temperature refrigerant passing through the second condenser entering the gas cooler, thereby controlling the gas-liquid ratio in the gas cooler.

3) In this system, the setting of the flow regulating valve can control the amount of refrigerant flowing into the second condenser, thereby controlling the ratio of the refrigerant flowing through the decompression part to the refrigerant flowing through the recondensing part.

4), the fourth temperature and pressure sensor is equivalent to being installed at the inlet of the compressor, which is beneficial to accurately control the temperature of the first condenser according to the temperature and pressure detected by the fourth temperature and pressure sensor during the compressor test process, eliminating the need for compression The test error caused by the improper control of the outlet temperature of the machine allows the volume space required for refrigerant mixing to be controlled. At the same time, the monitoring of multiple temperature and pressure sensors can prevent the refrigerant at the outlet of the first condenser and the refrigerant at the outlet of the second condenser from entering the gas-liquid two-phase region, which is beneficial to ensure the normal operation of the test system.

5), the present invention also proposes a cylindrical gas cooler, which provides a larger space for the mixing of the two refrigerants entering the gas cooler compared to the T-tube gas cooler, ensuring that the two refrigerants Refrigerant mixing is more thorough.

6), the present invention proposes a performance test method for refrigeration compressors, by cooling the refrigerant output from the compressor first and then diverting, so that the temperature of the refrigerant in gaseous form is lower, so that it can be compared with the condensed refrigerant at a smaller temperature. Heat exchange is carried out in the space, which reduces the footprint of the test system. At the same time, it also reduces the temperature difference before the two parts of refrigerant enter the mixed state, which is beneficial to accurately control the gas-liquid ratio after the two parts of refrigerant are mixed, thereby further improving the test accuracy of the compressor.

7) In the present invention, by monitoring the first temperature, the second temperature, the third temperature, the fourth temperature, the first pressure, the second pressure, the third pressure and the fourth pressure, it is equivalent to realizing the whole refrigeration The monitoring of the phase change process of the refrigerant in the refrigerant circulation circuit ensures the adequacy and completeness of the parameters for evaluating the performance of the compressor.

Description of drawings

Figure 1 is a flow chart of a method for testing the performance of a refrigeration compressor.

Figure 2 is a system diagram using a T-tube gas cooler.

Fig. 3 is a system diagram using a cylindrical gas cooler.

Figure 4 is a pressure-enthalpy diagram using a T-tube gas cooler.

Fig. 5 is a pressure-enthalpy diagram using a cylindrical gas cooler.

1. Compressor; 2. First condenser; 3. Flow regulating valve; 4. Gas throttle valve; 5. Second condenser; 6. Liquid throttle valve; 7. Gas cooler; 81. First temperature Pressure sensor; 82, second temperature and pressure sensor; 83, third temperature and pressure sensor; 84, fourth temperature and pressure sensor; 9, gas-liquid separator.

Detailed ways

A method for testing the performance of refrigeration compressors

A kind of refrigeration compressor performance test method that this embodiment proposes, comprises the following steps:

S1. The refrigerant output from the compressor is cooled and divided into two parts, one part is converted into low-pressure gaseous refrigerant, and the other part is condensed.

S2. Mix the above-mentioned low-pressure gaseous refrigerant and the condensed refrigerant and input them into the compressor to form a refrigerant circulation loop.

S3. Evaluate the performance of the compressor according to the temperature and pressure changes of the refrigerant in the refrigerant circulation circuit.

In this embodiment, the refrigerant output by the compressor is first cooled, and then divided into two parts, one part is further condensed to realize the cooling function, and the other part is used to mix with the condensed refrigerant in gaseous state, so as to pass through The mixing of the two parts of the refrigerant realizes the phase change of the refrigerant in the refrigerant cycle, thereby simulating the actual working conditions of the compressor.

In this embodiment, the refrigerant output by the compressor is cooled first and then diverted, so that the temperature of the refrigerant in the gaseous state is lower, so that heat exchange with the condensed refrigerant can be performed in a smaller space, reducing the size of the test system. of floor space. At the same time, it also reduces the temperature difference before the two parts of refrigerant enter the mixed state, which is beneficial to accurately control the gas-liquid ratio after the two parts of refrigerant are mixed, thereby further improving the test accuracy of the compressor.

In this embodiment, the temperature and pressure of the refrigerant output by the compressor are respectively recorded as the first temperature and the first pressure, and the temperature and pressure of the refrigerant output by the compressor after being cooled are respectively recorded as the second temperature and the second temperature. Pressure; the temperature and pressure after mixing the gaseous refrigerant and the condensed refrigerant are respectively recorded as the third temperature and the third pressure, and the temperature and pressure of the refrigerant input into the compressor are respectively recorded as the fourth temperature and the fourth temperature. pressure. In step S3, the performance of the compressor is evaluated according to the first temperature, the second temperature, the third temperature, the fourth temperature, the first pressure, the second pressure, the third pressure and the fourth pressure. In this embodiment, by monitoring the first temperature, the second temperature, the third temperature, the fourth temperature, the first pressure, the second pressure, the third pressure and the fourth pressure, it is equivalent to realizing the whole refrigerant cycle The monitoring of the phase change process of the refrigerant in the circuit ensures the adequacy and completeness of the parameters for evaluating the performance of the compressor.

A refrigeration compressor performance testing system

A refrigeration compressor performance testing system proposed in this embodiment includes: a pre-condensation unit, a pressure reduction unit, a re-condensation unit, a gas-liquid mixing unit and a monitoring unit.

The input end of the pre-condensing part is used to connect the output end of the compressor, and the output end of the pre-condensing part is respectively connected to the input end of the step-down part and the input end of the re-condensing part. That is, the pre-condensing unit is used to lower the temperature of the refrigerant output from the compressor 1, and then divide the cooled refrigerant into two parts, one part is input to the decompression unit, and the other part is input to the re-condensing unit.

Both the output end of the decompression unit and the output end of the recondensing unit are connected to the input end of the gas-liquid mixing unit, and the output end of the gas-liquid mixing unit is used to connect to the input end of the compressor 1 . The decompression part is used to convert the refrigerant from a high-pressure gaseous state to a low-pressure gaseous state, the recondensing part is used to condense the refrigerant, and the gas-liquid mixing part is used for the low-pressure gaseous refrigerant output from the decompression part and the low-temperature refrigerant output from the recondensing part. The liquid refrigerant is mixed and exchanged, and the mixed refrigerant returns to the input end of the compressor 1 again for circulation.

In this way, in this embodiment, the output end of the gas-liquid mixing part and the input end of the pre-condensing part constitute a test interface for connecting to a compressor, which facilitates the connection of different compressors to be tested.

In this embodiment, the ratio of the refrigerant flowing through the decompression portion to the refrigerant flowing through the recondensing portion can be adjusted, so as to control the phase change of the refrigerant mixed in the gas-liquid mixing portion. Specifically, in this embodiment, the recondensing part includes a second condenser 5 and a flow regulating valve 3, and the flow regulating valve 3 is arranged on a pipeline for connecting the input end of the second condenser 5 and the output end of the precondensing part In order to control the amount of refrigerant flowing into the second condenser 5 through the flow regulating valve 3, thereby controlling the ratio of the refrigerant flowing through the decompression part to the refrigerant flowing through the recondensing part. The output end of the second condenser 5 is connected to the gas-liquid mixing part through a pipeline.

Specifically, in this embodiment, the pre-condensing part can be implemented as an air-cooled condenser or a water-cooled condenser, which can be specifically recorded as the first condenser 2 so as to distinguish it from the second condenser 5 . The input end and the output end of the first condenser 2 are the input end and the output end of the pre-condensing part. The second condenser 5 can also be an air-cooled condenser or a water-cooled condenser. It is worth noting that when the first condenser 2 and the second condenser 5 both use water-cooled condensers, the water tanks used by the two should be independent of each other, so as to realize the independent cooling effect of the pre-condensation part and the re-condensation part, and further ensure the cooling effect of the compressor. An accurate test of performance.

In this embodiment, after the compressor, a pre-condensing part, that is, the first condenser 2 is added, and the setting of the first condenser plays the role of initially reducing the temperature of the refrigerant to control the refrigerant entering the second condenser and the decompression part temperature. Since the ratio of the condensed refrigerant mass to the uncondensed refrigerant mass in the gas-liquid mixing part is the reciprocal of the specific enthalpy of the two refrigerants entering the gas-liquid mixing part. Therefore, the temperature adjustment of the refrigerant by the first condenser 2 also indirectly controls the gas-liquid ratio in the gas-liquid mixing part, which is beneficial to ensure the sufficient mixing of the refrigerant gas and liquid, thereby avoiding unstable superheat and absorption The problem of temperature fluctuation of the gas is eliminated, which improves the test accuracy; at the same time, it also reduces the demand for the heat exchange space of the two refrigerants, which is conducive to reducing the footprint of the test system.

In this embodiment, the gas-liquid mixing part includes a gas cooler 7 and a return pipe. The gas cooler 7 is provided with a gas inlet, a liquid inlet, and a return port. The gas inlet is connected to the output end of the decompression part, and the liquid The inlet is connected to the output end of the recondensing part, the return port is connected to the first end of the return pipe, and the second end of the return pipe is used as the output end of the vapor-liquid mixing part to connect to the input end of the compressor 1 . The arrangement of the gas cooler 7 further ensures sufficient mixing of the two streams of refrigerant entering the gas-liquid mixing part.

In this embodiment, the depressurization part includes a gas throttle valve 4, which is arranged on a pipeline for connecting the output end of the precondensing part and the gas inlet. The setting of the gas throttling valve 4 realizes interception of the refrigerant flowing through the gas throttling valve 4 , thereby reducing the pressure of the refrigerant at the output end of the gas throttling valve 4 . A liquid throttling valve 6 is provided on the pipeline connecting the output end of the second condenser 5 and the liquid inlet. The setting of the liquid throttling valve 6 is beneficial to control the amount of the low-temperature refrigerant passing through the second condenser 5 entering the gas cooler 7 , thereby controlling the gas-liquid ratio in the gas cooler 7 .

In this embodiment, a gas-liquid separator 9 is provided between the return port and the input end of the compressor 1 to ensure that the compressor 1 only compresses the gaseous refrigerant and prevents liquid refrigerant from flowing into the compressor 1 Liquid hammer phenomenon.

In this embodiment, the monitoring unit is used to detect the temperature and pressure of the refrigerant in the refrigerant cycle circuit composed of the pre-condensing part, the decompression part, the re-condensing part, the gas-liquid mixing part and the compressor, so as to The state change of the refrigerant in judging the performance of the compressor

Specifically, in this embodiment, the monitoring unit includes a first temperature and pressure sensor 81 , a second temperature and pressure sensor, a third temperature and pressure sensor, and a fourth temperature and pressure sensor. The first temperature and pressure sensor 81 is used to detect the temperature and pressure of the refrigerant input into the first condenser 2 , that is, the first temperature and pressure sensor 81 is arranged on the pipeline connected to the input end of the first condenser 2 . The second temperature and pressure sensor 82 is used to detect the temperature and pressure of the refrigerant output from the first condenser 2 , that is, the second temperature and pressure sensor 82 is arranged on the pipeline connected to the output end of the first condenser 2 . The third temperature and pressure sensor 83 is used to detect the temperature and pressure of the mixed refrigerant in the gas-liquid mixing part. In this embodiment, the third temperature and pressure sensor 83 is arranged at the first end of the return pipe. The fourth temperature and pressure sensor 84 is used to detect the temperature and pressure of the refrigerant input into the compressor, that is, the fourth temperature and pressure sensor 84 is arranged at the second end of the return pipe.

In this embodiment, the fourth temperature and pressure sensor 84 is equivalent to being installed at the inlet of the compressor, which is beneficial to accurately control the temperature of the first condenser 2 according to the temperature and pressure detected by the fourth temperature and pressure sensor during the compressor test process. , eliminating the test error caused by unsuitable control of the outlet temperature of the compressor, so that the volume space required for refrigerant mixing can be controlled. At the same time, the monitoring of multiple temperature and pressure sensors can prevent the refrigerant at the outlet of the first condenser 2 and the outlet of the second condenser 5 from entering the gas-liquid two-phase region, which is beneficial to ensure the normal operation of the test system.

T-tube gas cooler

In this embodiment, the above-mentioned gas cooler 7 adopts a T-shaped tube, and the three ports of the T-shaped tube of the gas cooler 7 are respectively used as a gas inlet, a liquid inlet and a return port. That is, the gaseous refrigerant output from the decompression section and the low-temperature refrigerant output from the recondensing section are directly mixed in the pipeline. Specifically, in this embodiment, there is no limitation on the corresponding relationship between the three ports on the T-shaped tube and the gas inlet, the liquid inlet, and the return port.

At this time, in order to ensure that the two streams of refrigerant entering the T-shaped tube can fully mix and exchange heat, the inner diameter of the T-shaped tube should be 3 to 5 times the inner diameter of the outlet pipe, and the length of the T-shaped tube should be 3-5 times that of the outlet pipe. 8 to 12 times the inner diameter of the tube. The air outlet pipe is a pipe for connecting the return port and the input end of the compressor 1 , that is, a pipe for transporting the refrigerant output from the gas cooler 7 to the input end of the compressor 1 .

Specifically, the gas cooler with a T-tube structure proposed in this embodiment is suitable for a process where the difference between the outlet enthalpy h ₂ of the compressor 1 and the outlet enthalpy h ₂ ′ of the first condenser 2 is greater than 0.6 times that of the compressor 1. In the case of outlet enthalpy difference (h ₁ -h ₂ ), that is, h ₂ -h ₂ '>0.6×(h ₁ -h ₂ ); h ₁ is the inlet enthalpy value of compressor 1 .

Fig. 3 shows the circulation process of the refrigerant in the refrigerant circulation circuit in this embodiment on the logP-h diagram, and the numbers in the figure are all for the state of the refrigerant. State point 0 means that the refrigerant is in a saturated state; state point 1 means that the refrigerant is in a superheated state, that is, the refrigerant state at the inlet of compressor 1; state point 2 represents that the refrigerant is in a high-pressure gas state, that is, the refrigerant at the outlet of compressor 1 state; state point 2' represents the state of the high-pressure gaseous refrigerant after the initial cooling of the first condenser 2, that is, the state of the refrigerant at the output end of the first condenser 2; state point 2" represents that the refrigerant at state point 2' has passed gas throttling The state after valve 4 is throttled and depressurized; state point 3 represents the saturated state of the refrigerant at state point 2' after passing through the second condenser 5; state point 4 represents the refrigerant at state point 3 passing through the second condenser 5 The supercooled state after cooling down; state point 5 represents the state of the refrigerant in state point 4 after passing through the liquid throttling valve 6 and reducing the pressure.

It is worth noting that the refrigerant at state point 2' is still superheated. The refrigerant at state point 5 is in the gas-liquid two-phase region.

In the refrigerant circulation circuit, the refrigerant at state point 5 is mixed with the refrigerant at state point 2” in the gas cooler 7, and then the refrigerant returns to the inlet of compressor 1, which is state point 1, to continue the next cycle. It is worth It should be noted that the state point after the initial cooling of the first condenser 2 should be between state point 2 and state point 3, and cannot reach the two-phase region. The most ideal is to reach the state point after initial cooling from state point 2 3, that is, the state point 2' shown in Figure 5 coincides with state point 3, which means that the first condenser 2 directly cools the refrigerant at state point 2 output by compressor 1 to a saturated state, that is, state point 3. At this time, the required The gas cooler 7 has the smallest volume, and can even spray liquid directly in the main pipeline for cooling.

Barrel Gas Cooler

In this embodiment, the above-mentioned gas cooler 7 adopts a cylindrical body.

In this embodiment, the pipeline connected to the liquid inlet and used to input the refrigerant passing through the recondenser into the gas cooler 7 is referred to as the liquid inlet pipe, that is, the liquid inlet pipe is connected to the liquid inlet of the gas cooler 7 and Pipe between liquid throttle valve 6. The pipeline connected to the gas inlet and used to input the refrigerant passing through the decompression part into the gas cooler 7 is referred to as an intake pipe, that is, the intake pipe is a pipeline connected between the gas inlet and the gas throttle valve 4 . The pipe connected to the return port for outputting the refrigerant in the gas cooler 7 is recorded as the gas pipe. The inner diameter of the liquid inlet pipe, the inner diameter of the inlet pipe and the inner diameter of the outlet pipe are denoted as d ₅ , d ₂ and d ₁ respectively.

When the gas cooler 7 adopts a cylinder with both ends sealed, the liquid inlet is arranged at the bottom of the cylinder, the gas inlet is arranged at the middle of the cylinder, and the return port is arranged at the top of the cylinder. That is, the liquid inlet, the gas inlet and the return port are arranged from bottom to top on the cylinder as the gas cooler 7, that is, the axis of the cylinder is placed in a vertical direction, the liquid inlet is located at the bottom of the cylinder, and the gas inlet is located at the bottom of the cylinder. In the middle of the cylinder, the return port is located at the top of the cylinder.

In this embodiment, as the cylinder of the gas cooler 7, its height is 1.5 to 3 times its inner diameter _d3 , and:

d ₂ /d ₅ =[(h ₁ -h ₅ )v ₂ /(h ₂ -h ₁ )v ₅ ] ^0.5 ;

d ₂ /d ₅ =[(h ₁ -h ₅ )v ₂ /(h ₂ -h ₁ )v ₅ ] ^0.5 ;

d ₁ =1.2d ₅ [(h ₂ -h ₁ )v ₁ /(h ₂ -h ₅ )v ₅ ] ^0.5 ;

Among them, h ₁ is the inlet enthalpy value of compressor 1, h ₂ is the outlet enthalpy value of compressor, h ₅ is the enthalpy value at the outlet of liquid throttling valve 6; v ₁ is the specific volume of gas refrigerant input into compressor 1 , v ₂ is the specific volume of the liquid refrigerant output from the compressor 1, v ₅ is the specific volume of the refrigerant output from the recondenser to the gas cooler 7, that is, v ₅ is the ratio of the refrigerant output from the second condenser 5 Allow.

Compared with the T-tube gas cooler 7, the cylindrical gas cooler 7 provided in this embodiment provides a larger space for the mixing of the two refrigerants entering the gas cooler 7, ensuring that the two refrigerants more fully mixed. The cylinder type gas cooler 7 is suitable for the difference between the outlet enthalpy value h ₂ of the compressor 1 and the outlet enthalpy value h ₂ ′ of the first condenser 2 is less than or equal to 0.6 times the compressor 1 inlet and outlet enthalpy difference (h ₁ -h ₂ ), that is, h ₂ -h ₂ '≤0.6×(h ₁ -h ₂ ).

Hereinafter, the present invention will be further explained in conjunction with two specific embodiments.

Example 1

The compressor performance test system in this embodiment is shown in Figure 2. In this embodiment, the refrigerant is R134a, its evaporation temperature is 7.2°C, its condensation temperature is 54.4°C, and the superheat at the compressor inlet is 8°C. The subcooling degree of the second condenser is 2°C.

In this embodiment, the enthalpy value at point 1 is 409.93KJ/Kg, the enthalpy value at point 2 is 468.95KJ/Kg, the enthalpy value at points 4 and 5 is 275.20KJ/Kg, and the enthalpy value at point 3' is 421.44KJ/Kg. The enthalpy value of 6' is 395.56KJ/Kg.

In this embodiment, the enthalpy value of 2' ranges from 421.44KJ/Kg to 433.54KJ/Kg, that is, the enthalpy difference between the two ends of the first condenser 2 h ₂ -h ₂ ' accounts for the enthalpy difference between the inlet and outlet of the compressor 1 h ₁ -h More than 60% of ₂ . At this time, the temperature of the gaseous refrigerant entering the gas cooler 7 is relatively low, and the space required for the phase transition of the liquid refrigerant is very small, so the T-tube gas cooler 7 is selected.

Example 2

The compressor performance test system in this embodiment is shown in Figure 3. Compared with Embodiment 1, the range of the enthalpy value of 2' is 433.54KJ/Kg-468.95KJ/Kg, that is, the enthalpy at both ends of the first condenser 2 The difference h ₂ -h ₂ 'accounts for less than 60% of the enthalpy difference h ₁ -h ₂ between the inlet and outlet of the compressor 1. Under this working condition, the temperature of the gas refrigerant entering the gas cooler 7 is relatively high, and the phase change of the liquid refrigerant requires The space is larger, so the gas cooler 7 adopts a cylinder type gas cooler. Moreover, in this embodiment, d ₂ =4.5×d ₅ , d ₁ =5.5×d ₅ , and the height of the cylinder is 1.5 to 3 times the inner diameter d ₃ of the cylinder.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection.

Claims (10)

1. A refrigeration compressor performance testing system, characterized in that it includes: a pre-condensation unit, a depressurization unit, a re-condensation unit, a gas-liquid mixing unit and a monitoring unit;

   The output end of the pre-condensation part is respectively connected to the input end of the step-down part and the input end of the re-condensation part; the output end of the step-down part and the output end of the re-condensation part are both connected to the input end of the gas-liquid mixing part, and the The output end and the input end of the pre-condensing part constitute a test interface for connecting to the compressor, wherein the output end of the gas-liquid mixing part is used to connect the input end of the compressor (1), and the input end of the pre-condensing part is used to connect the output of the compressor;

   The pre-condensing part is used to cool down the refrigerant output from the compressor (1); the refrigerant output from the pre-condensing part is divided into two parts, one of which is in a low-pressure gas state after passing through the decompression part, and the other part is condensed through the re-condensing part; The low-pressure gaseous refrigerant output from the pressure section and the low-temperature liquid refrigerant output from the recondensing section are mixed through the gas-liquid mixing section and then returned to the input end of the compressor (1); Refrigerant ratio is adjustable;

   The monitoring part is used to detect the temperature and pressure of the refrigerant in the refrigerant circulation circuit composed of the pre-condensing part, the decompression part, the re-condensing part, the gas-liquid mixing part and the compressor.
2. The refrigeration compressor performance testing system according to claim 1, wherein the gas-liquid mixing part includes a gas cooler (7) and a return pipe, and the gas cooler (7) is provided with a gas inlet, a liquid inlet and a return port , the gas inlet is connected to the output end of the decompression part, the liquid inlet is connected to the output end of the recondensing part, the return port is connected to the first end of the return pipe, and the second end of the return pipe is used as the gas-liquid mixing part output.
3. The refrigeration compressor performance testing system according to claim 2, wherein the recondensing part comprises a second condenser (5) and a flow regulating valve (3), and the flow regulating valve (3) is set for connecting On the pipes between the input end of the second condenser (5) and the output end of the precondenser, the output end of the second condenser (5) is connected to the liquid inlet through a pipe.
4. The refrigeration compressor performance testing system according to claim 3, wherein the decompression part includes a gas throttling valve (4), and the gas throttling valve (4) is arranged at the output end for connecting the precondensing part and the pipeline of the gas inlet; the pipeline for connecting the output end of the second condenser (5) and the liquid inlet is provided with a liquid throttling valve (6).
5. The refrigeration compressor performance testing system according to claim 2, characterized in that, a gas-liquid separator (9) is further provided between the return port and the input end of the compressor (1).
6. The refrigeration compressor performance testing system according to claim 1, wherein the gas cooler (7) adopts a T-shaped tube or a cylinder with both ends sealed;

   When the gas cooler (7) adopts a T-shaped tube, its three ports are respectively used as gas inlet, liquid inlet and return port;

   When the gas cooler (7) adopts a cylinder with both ends sealed, the liquid inlet is arranged at the lower part of the cylinder, the gas inlet is arranged at the middle of the cylinder, and the return port is arranged at the upper part of the cylinder.
7. The refrigeration compressor performance testing system according to claim 6, characterized in that, the pipeline connected to the liquid inlet and used to input the refrigerant through the recondensing part into the gas cooler (7) is designated as a liquid inlet pipe, The pipeline that is connected with the gas inlet and is used to input the refrigerant through the decompression part into the gas cooler (7) is designated as an intake pipe, and is connected with the return port for outputting the refrigeration in the gas cooler (7). The pipeline of the agent is recorded as the air outlet pipe; the pipe inner diameter of the liquid inlet pipe, the pipe inner diameter of the air inlet pipe and the pipe inner diameter of the air outlet pipe are respectively recorded as _d5 , _d2 and _d1 ;

   When the gas cooler (7) adopts a T-shaped tube, the inner diameter of the T-shaped tube is 3 to 5 times the inner diameter of the air outlet pipe, and the length of the T-shaped pipe is 8 to 12 times the inner diameter of the air outlet pipe;

   When the gas cooler (7) adopts a cylinder with both ends sealed, the height of the cylinder is 1.5 to 3 times the inner diameter _d3 of the cylinder, and:

   d ₂ /d ₅ =[(h ₁ -h ₅ )v ₂ /(h ₂ -h ₁ )v ₅ ] ^0.5 ;

   d ₂ /d ₅ =[(h ₁ -h ₅ )v ₂ /(h ₂ -h ₁ )v ₅ ] ^0.5 ;

   d ₁ =1.2d ₅ [(h ₂ -h ₁ )v ₁ /(h ₂ -h ₅ )v ₅ ] ^0.5 ;

   Among them, h ₁ is the inlet enthalpy value of the compressor (1), h ₂ is the outlet enthalpy value of the compressor, h ₅ is the enthalpy value at the outlet of the liquid throttling valve (6); v ₁ is the input compressor (1) enthalpy value The specific volume of the gas refrigerant, v ₂ is the specific volume of the liquid refrigerant output from the compressor (1), and v ₅ is the specific volume of the refrigerant output from the recondensing part to the gas cooler (7).
8. The refrigeration compressor performance testing system according to claim 1, wherein the monitoring section includes a first temperature and pressure sensor (81), a second temperature and pressure sensor, a third temperature and pressure sensor and a fourth temperature and pressure sensor; the first The temperature and pressure sensor (81) is used to detect the temperature and pressure of the refrigerant input into the first condenser (2), and the second temperature and pressure sensor (82) is used to detect the temperature and pressure of the refrigerant output from the first condenser (2). Pressure, the third temperature and pressure sensor (83) is used to detect the temperature and pressure of the refrigerant mixed in the gas-liquid mixing part, and the fourth temperature and pressure sensor (84) is used to detect the temperature and pressure of the refrigerant input into the compressor .
9. A performance testing method for a refrigeration compressor, characterized in that it comprises the following steps:

   S1. The refrigerant output by the compressor is cooled and divided into two parts, one part is converted into low-pressure gaseous refrigerant, and the other part is condensed;

   S2. Mix the above-mentioned low-pressure gaseous refrigerant and the condensed refrigerant into the compressor to form a refrigerant circulation loop;

   S3. Evaluate the performance of the compressor according to the temperature and pressure changes of the refrigerant in the refrigerant circulation circuit.
10. The refrigeration compressor performance test method according to claim 9, wherein the temperature and pressure of the refrigerant output by the compressor are respectively recorded as the first temperature and the first pressure, and the refrigerant output by the compressor is cooled The temperature and pressure are respectively recorded as the second temperature and the second pressure; the temperature and pressure after mixing the gaseous refrigerant and the condensed refrigerant are respectively recorded as the third temperature and the third pressure, and the refrigerant input into the compressor The temperature and pressure are respectively recorded as the fourth temperature and the fourth pressure; in step S3, according to the first temperature, the second temperature, the third temperature, the fourth temperature, the first pressure, the second pressure, the third pressure and the fourth Pressure assesses compressor performance.

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