Railway vehicle air conditioning unit capable of adjusting refrigerating capacity in stepless mode

Abstract

The railway vehicle air conditioning unit is arranged in an installation space at the top of a carriage and comprises a compressor, a condenser and an evaporator, the compressor and the condenser are connected through a pipeline, the condenser and the evaporator are connected through a pipeline, and the evaporator and the compressor are connected through a pipeline. The output end of the compressor conveys a compressed high-temperature and high-pressure gaseous refrigerant to the condenser through a pipeline to be cooled and condensed, the cooled and condensed liquid refrigerant is conveyed into the evaporator through a pipeline, and low-temperature air cooled by the evaporator is conveyed to a compartment to reduce the temperature of air in the compartment. Meanwhile, the refrigerant absorbs heat, is gasified and then flows back to the input end of the compressor, and an expansion valve is connected to a pipeline between the condenser and the evaporator; the air conditioner further comprises an adjusting branch and a heat exchanger, one end of the adjusting branch is connected to a pipeline between the condenser and the evaporator and located on the upstream of the expansion valve, the other end of the adjusting branch is connected with the input end of the compressor, and a bypass electronic expansion valve is connected to the adjusting branch. The heat exchanger is connected with at least part of the adjusting branch and a pipeline between the compressor and the condenser in a sleeved mode, when the bypass electronic expansion valve is opened, refrigerants flowing back to the input end of the compressor on the adjusting branch absorb heat and are gasified through heat conduction of the heat exchanger, and the temperature of the refrigerants output from the output end of the compressor is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of rail vehicle air conditioning, and in particular to a rail vehicle air conditioning unit with stepless cooling capacity adjustment. Background Art

[0002] Refrigeration and air conditioning units are essential components of rail vehicles. When the vehicle is running, the heat load fluctuates greatly with the changes in the external environment and passenger flow. When the heat load of the train changes, the air conditioning unit needs to be able to easily adjust the refrigeration capacity. Otherwise, when the air conditioning unit is running in a high temperature environment, high pressure protection is likely to occur; when it is running in a low temperature environment, evaporator frost and low pressure protection are likely to occur; when it is running under partial load conditions, the compressor is likely to start and stop frequently, affecting the service life of the compressor and causing large fluctuations in the temperature inside the vehicle.

[0003] Currently, variable frequency compressors can also achieve a wide range of cooling capacity adjustments, but variable frequency air conditioning units are expensive, add more electronic control components, are more complex, and have low reliability, while the rail industry has very high requirements for reliability.

[0004] Therefore, there is still a need for a rail vehicle air conditioning unit with stepless cooling capacity adjustment to solve the above problems. Utility Model Content

[0005] The present application provides a rail vehicle air conditioning unit with stepless cooling capacity adjustment to solve the above-mentioned problem.

[0006] The purpose of this application is achieved by the following technical solutions:

[0007] A rail vehicle air-conditioning unit with stepless cooling capacity adjustment is arranged in an installation space on the top of a car, and is characterized in that it comprises: a compressor, a condenser and an evaporator, wherein the compressor and the condenser, the condenser and the evaporator, and the evaporator and the compressor are connected by pipelines, the output end of the compressor transports the compressed high-temperature and high-pressure gaseous refrigerant to the condenser through a pipeline for cooling, and transports the cooled liquid refrigerant into the evaporator through a pipeline, and the low-temperature air cooled by the evaporator is transported to the car to reduce the air temperature in the car, and the refrigerant absorbs heat and vaporizes and then flows back to the input end of the compressor, and an expansion valve is connected to the pipeline between the condenser and the evaporator.

[0008] It also includes a regulating branch and a heat exchanger, one end of the regulating branch is connected to the pipeline between the condenser and the evaporator and is located upstream of the expansion valve, and the other end is connected to the input end of the compressor. A bypass electronic expansion valve is connected to the regulating branch.

[0009] The heat exchanger is connected to at least a portion of the regulating branch and the pipeline between the compressor and the condenser. When the bypass electronic expansion valve is opened, the refrigerant on the regulating branch that flows back to the input end of the compressor absorbs heat and vaporizes through heat conduction of the heat exchanger, and the temperature of the refrigerant output from the output end of the compressor is reduced.

[0010] In one embodiment, it also includes a condensing fan and an evaporating fan. The condensing fan is arranged near the condenser and blows air toward the condenser to reduce the temperature of the refrigerant in the condenser. The evaporating fan is arranged near the evaporator and draws air from the evaporator to blow cold air into the vehicle compartment.

[0011] In one embodiment, a drying filter and a sight glass are sequentially connected to the pipeline between the condenser and the evaporator and upstream of the connection point between the regulating branch and the pipeline between the condenser and the evaporator.

[0012] In one embodiment, a return air door assembly is further included. The return air assembly is arranged at the top of the compartment and connects the interior of the compartment with the installation space, and is used to send part of the air in the compartment into the installation space and then send it back to the compartment through the evaporator.

[0013] In one embodiment, a fresh air component is also included, which is arranged on the top of the car and connects the installation space with the outside world. It is used to suck the outside air into the installation space, mix the outside air with part of the air in the car, and send it back to the car through an evaporator.

[0014] In one embodiment, the evaporator is tilted relative to the length direction of the vehicle compartment in the installation space, a mixed air filter is provided on one side of the evaporator close to the return air assembly, and a heating wire and a wind resistance adjustment orifice plate are connected to the other side of the evaporator.

[0015] Compared with the prior art, the beneficial effects of this application include at least:

[0016] By setting a regulating branch between the pipes connecting the condenser and the evaporator, the electronic expansion valve on the regulating branch controls the flow of the refrigerant flowing back to the compressor through the regulating branch, which can adjust the cooling capacity generated by the evaporator toward the car compartment. On the other hand, through the heat conduction of the heat exchanger, part of the high-temperature and high-pressure gaseous refrigerant output after being compressed by the compressor is initially cooled, reducing the condensation pressure of the rear condenser, preventing the compressor from shutting down due to excessive condensation pressure, and improving the high temperature resistance of the air-conditioning unit. At the same time, the refrigerant that has been vaporized by heat conduction and absorption is input into the compressor in a gaseous form, avoiding frequent start and stop of the compressor, making the temperature control in the car compartment more accurate, and at the same time increasing the service life of the compressor, simplifying the structural components of the variable frequency control, and having a simple structure and improved reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the refrigeration system principle of the first embodiment of the present application;

[0018] Figure 2 It is a structural diagram of Embodiment 2 of the present application;

[0019] Figure 3 It is a schematic diagram of the wind resistance adjustment plate hole structure of the second embodiment of the present application.

[0020] In the figure: 1. compressor; 2. condenser; 3. evaporator; 4. regulating branch; 6. expansion valve; 7. electronic expansion valve; 8. condensing fan; 9. evaporating fan; 10. drying filter; 11. sight glass; 12. return air door assembly; 13. fresh air assembly; 14. installation space; 15. mixed air filter; 16. heating wire; 17. wind resistance regulating orifice plate; 18. plate heat exchanger. DETAILED DESCRIPTION

[0021] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete and to fully convey the concepts of example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their repeated description will be omitted.

[0022] The words expressing position and direction described in this application are all explained with reference to the accompanying drawings as examples, but they can be changed as needed, and all changes are included in the scope of protection of this application.

[0023] Reference Figure 1-3The present application provides a rail vehicle air-conditioning unit with stepless cooling capacity adjustment, which is arranged in an installation space 14 on the top of a carriage, and includes: a compressor 1, a condenser 2 and an evaporator 3. The compressor 1 and the condenser 2, the condenser 2 and the evaporator 3, and the evaporator 3 and the compressor 1 are connected by pipelines. The output end of the compressor 1 transports the compressed high-temperature and high-pressure gaseous refrigerant to the condenser 2 through a pipeline for cooling and condensing, and transports the cooled and condensed liquid refrigerant into the evaporator 3 through a pipeline. The low-temperature air cooled by the evaporator 3 is transported into the carriage to reduce the air temperature in the carriage. At the same time, the refrigerant vaporizes and flows back to the input end of the compressor 1. An expansion valve 6 is connected to the pipeline between the condenser 2 and the evaporator 3. When the compressor 1 is working, it compresses the sucked low-temperature and low-pressure refrigerant into a high-temperature and high-pressure gaseous refrigerant, and then the high-temperature and high-pressure gaseous refrigerant is transported through the pipeline to be cooled and condensed by the condenser 2 to form a high-temperature liquid refrigerant. Then, the liquid refrigerant is throttled and reduced in pressure by the expansion valve 6 to initially form a refrigerant containing part of the gaseous state, and finally transported to the evaporator 3 through the pipeline, where it absorbs heat and vaporizes, completely changing from liquid to gaseous state. The air flowing through the evaporator 3 is cooled and then transported to the interior of the vehicle by the evaporator 3 to achieve the purpose of cooling. At the same time, the gaseous refrigerant flows back to the input end of the compressor 1, and after being compressed, it circulates again to participate in the above work.

[0024] The refrigerant used here is, for example, ammonia or Freon-based refrigerant, but is not limited thereto.

[0025] It also includes a regulating branch 4 and a heat exchanger, one end of the regulating branch 4 is connected to the pipeline between the condenser 2 and the evaporator 3, and is located upstream of the expansion valve 6, and the other end is connected to the input end of the compressor 1, and the regulating branch 4 is connected to the bypass electronic expansion valve 7. The regulating branch 4 is connected between the condenser 2 and the evaporator 3, and is back-connected to the input end of the compressor 1. The heat exchanger is, for example, a plate heat exchanger 18, and the plate heat exchanger 18 has a plurality of mutually isolated flow channels inside, so that the gas-liquid mixed refrigerant that flows back through the regulating branch 4 and is throttled and depressurized by the bypass electronic expansion valve 7 is heat-exchanged with the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 1, reducing the heat exchange amount and condensation pressure of the condenser 2, and preventing the compressor 1 from shutting down due to excessive condensation pressure. In addition, the refrigerant that does not participate in the refrigeration in the vehicle absorbs heat and vaporizes into a gas state, and flows back to the input end of the compressor 1, preventing the compressor 1 from inhaling liquid refrigerant and causing damage.

[0026] The heat exchanger is connected to at least part of the regulating branch 4 and the pipeline between the compressor 1 and the condenser 2. When the bypass electronic expansion valve 7 is opened, the refrigerant on the regulating branch 4 that flows back to the input end of the compressor 1 absorbs heat and vaporizes through heat conduction of the heat exchanger, and reduces the temperature of the refrigerant output from the output end of the compressor 1. The electronic expansion valve 7 is connected to the power supply and the controller through external wires to control the flow of the refrigerant on the regulating branch 4, thereby controlling the corresponding working mode of the entire rail vehicle air-conditioning unit under different working requirements.

[0027] When the air-conditioning unit is running at full load, the bypass electronic expansion valve 7 is closed, and the exhaust gas of compressor 1 flows through the heat exchanger (without heat exchange) and then enters the condenser 2, and then flows through the drying filter 10, the sight glass 11, the expansion valve 6 and the evaporator 3 in sequence, and then returns to the compressor 1.

[0028] When the air-conditioning unit is running at partial load, the bypass electronic expansion valve 7 is opened, and part of the bypassed refrigerant flows through the heat exchanger to absorb the exhaust heat of the compressor 1 and then returns to the compressor 1; after the bypass electronic expansion valve 7 is opened, the refrigerant flow through the expansion valve 6 and the evaporator 3 is reduced, and the cooling capacity is reduced, thereby realizing the cooling capacity regulation. The opening degree of the bypass electronic expansion valve 7 can be adjusted to realize stepless regulation of the cooling capacity.

[0029] After the bypass electronic expansion valve 7 is opened, part of the bypassed refrigerant is throttled and reduced in pressure when passing through the bypass electronic expansion valve 7, and returns to the suction port of the compressor 1 after absorbing the exhaust heat of the compressor 1 when passing through the heat exchanger. Under low temperature conditions, the refrigerant in this bypass circuit can increase the suction temperature of the compressor 1, thereby improving the refrigeration operation capacity of the unit under low temperature conditions.

[0030] In one embodiment, a condensing fan 8 and an evaporating fan 9 are further included. The condensing fan 8 is arranged near the condenser 2 and blows air toward the condenser 2 to reduce the temperature of the refrigerant in the condenser 2. The evaporating fan 9 is arranged near the evaporator 3 and sucks air from the evaporator 3 to blow cold air into the vehicle compartment. The condensing fan 8 and the evaporating fan 9 are both connected to the power supply inside the vehicle compartment through wires. When working, the air flow rate on the surface of the condenser 2 and the evaporator 3 is accelerated, so that the refrigerant inside the condenser 2 releases heat and condenses, and the refrigerant inside the evaporator 3 absorbs heat and vaporizes, thereby reducing the air temperature in the vehicle compartment.

[0031] In a specific embodiment, a drying filter 10 and a sight glass 11 are sequentially connected to the pipeline between the condenser 2 and the evaporator 3 and upstream of the connection point between the regulating branch 4 and the pipeline between the condenser 2 and the evaporator 3. The drying filter 10 filters out impurities in the pipeline to ensure the normal operation of the entire refrigeration system and prevent damage to other components. In addition, the sight glass 11 can clearly see the liquid condition of the refrigerant after passing through the condenser 2, which is convenient for maintenance personnel to check the operation of the refrigeration system.

[0032] More specifically, it also includes a return air door assembly 12, which is arranged at the top of the compartment to connect the interior of the compartment and the installation space 14, and is used to send part of the air in the compartment into the installation space 14 and return it to the compartment through the evaporator 3. The return air assembly can be an openable and closable fan window, which connects the air inside the compartment and the installation space 14 on the top when opened, and forms a negative pressure through the airflow generated by the evaporating fan 9, so that the air in the compartment is sucked in and discharged into the compartment again after passing through the evaporator 3 to form cold air, thereby forming a circulating refrigeration of the internal air.

[0033] In one embodiment, a fresh air component 13 is further included, and the fresh air component 13 is arranged on the top of the compartment, connecting the installation space 14 and the outside, and is used to suck the outside air into the installation space 14, and mix the outside air with part of the air in the compartment and send it back to the compartment through the evaporator 3. The fresh air component 13 is, for example, a closed pipe, with an opening on one side located outside the compartment and the other side corresponding to the installation space 14. The fresh air component 13 is connected with valves. When the valves are opened, the fresh air from the outside is blown into the installation space 14, and is mixed with the internal circulating air, and is sent into the compartment after being cooled, so as to ensure that there is sufficient fresh air in the compartment.

[0034] In another embodiment, the evaporator 3 is arranged at an angle relative to the length direction of the compartment, and a mixed air filter 15 is arranged on one side of the evaporator 3 close to the return air assembly, and the mixed air filter 15 is, for example, a filter frame with a metal mesh. The other side of the evaporator 3 is connected with a heating wire 16 and a wind resistance adjustment orifice plate 17. In actual use, the refrigeration system composed of the compressor 1, the condenser 2 and the evaporator 3 can be divided into two groups. The two groups of inclined evaporators 3 are distributed in an eight-shaped shape, which can save the installation space 14 on the top of the compartment, and the inclined wind resistance adjustment plate is distributed with holes. The hole diameter on the wind resistance adjustment plate close to the evaporator fan 9 is the smallest, and the hole diameter gradually increases toward the side away from the evaporator fan 9, which is used to balance the air flow velocity flowing through various parts of the evaporator 3, so that various parts of the evaporator 3 are evenly exchanged. The heating wire 16 is connected to the power supply during heating, and the heated hot air is injected into the compartment through the evaporator fan 9.

[0035] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the application without departing from the principles and purpose of the present application. All of these changes should fall within the scope of protection of the claims of the present application.

Claims

1. A rail vehicle air conditioning unit with stepless cooling capacity adjustment, arranged in the installation space on the top of the carriage, characterized in that: include: A compressor, a condenser and an evaporator, wherein the compressor and the condenser, the condenser and the evaporator, and the evaporator and the compressor are connected by pipelines, the output end of the compressor transports the compressed high-temperature and high-pressure gaseous refrigerant to the condenser through the pipeline for cooling, and transports the cooled liquid refrigerant into the evaporator through the pipeline, and the low-temperature air cooled by the evaporator is transported to the compartment to reduce the air temperature in the compartment, and the refrigerant absorbs heat and vaporizes and flows back to the input end of the compressor, and an expansion valve is connected to the pipeline between the condenser and the evaporator; It also includes a regulating branch and a heat exchanger, one end of the regulating branch is connected to the pipeline between the condenser and the evaporator and is located upstream of the expansion valve, and the other end is connected to the input end of the compressor, and a bypass electronic expansion valve is connected to the regulating branch; The heat exchanger is connected to at least a portion of the regulating branch and the pipeline between the compressor and the condenser. When the bypass electronic expansion valve is opened, the refrigerant on the regulating branch that flows back to the input end of the compressor absorbs heat and vaporizes through heat conduction of the heat exchanger, and the temperature of the refrigerant output from the output end of the compressor is reduced.

2. The rail vehicle air conditioning unit according to claim 1, characterized in that: It also includes a condensing fan and an evaporating fan. The condensing fan is arranged near the condenser and blows air toward the condenser to reduce the temperature of the refrigerant in the condenser. The evaporating fan is arranged near the evaporator and draws air from the evaporator to blow cold air into the vehicle compartment.

3. The rail vehicle air conditioning unit according to claim 2, characterized in that: A drying filter and a sight glass are sequentially connected on the pipeline between the condenser and the evaporator and upstream of the connection point between the regulating branch and the pipeline between the condenser and the evaporator.

4. The rail vehicle air conditioning unit according to claim 3, characterized in that: It also includes a return air door assembly, which is arranged on the top of the car and connects the interior of the car with the installation space, and is used to send part of the air in the car into the installation space and then send it back to the car through the evaporator.

5. The rail vehicle air conditioning unit according to claim 4, characterized in that: It also includes a fresh air component, which is arranged on the top of the car, connecting the installation space and the outside world, and is used to suck the outside air into the installation space, and mix the outside air with part of the air in the car and send it back to the car through an evaporator.

6. The rail vehicle air conditioning unit according to claim 4, characterized in that: The evaporator is arranged in an inclined manner relative to the length direction of the vehicle compartment in the installation space, a mixed air filter is arranged on one side of the evaporator close to the return air door assembly, and a heating wire and a wind resistance adjustment orifice plate are connected to the other side of the evaporator.

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