Air conditioning system suitable for low-load refrigeration operation

Abstract

The utility model relates to an air conditioning system suitable for low-load refrigeration operation, and relates to the technical field of air conditioning refrigeration. Comprising a first evaporator, a second evaporator, a compressor, a condenser, a first connecting pipeline, a second connecting pipeline, a third connecting pipeline, a fourth connecting pipeline and a control part. The first connecting pipeline is connected with the condenser and the first evaporator, and a first electronic expansion valve is arranged on the pipeline; the second connecting pipeline is connected with the condenser and the second evaporator, and a second electronic expansion valve is arranged on the second connecting pipeline; one end of the third connecting pipeline is connected with the first evaporator and the second evaporator; the fourth connecting pipeline is connected with the compressor and the condenser; the control piece is electrically connected with the first electronic expansion valve and the second electronic expansion valve. When the operation frequency of the compressor is larger than the valve opening frequency of the electronic expansion valves, the second electronic expansion valve is opened, the second evaporator is started, and the cooling temperature is increased.

Description

TECHNICAL FIELD

[0001] The utility model relates to air conditioning refrigeration technical field, especially suitable for low load refrigeration operation's air conditioning system. BACKGROUND

[0002] In order to ensure the normal working temperature of the data center server, a refrigeration device is configured to cool and dissipate heat for the IT server. Since the data center project, the general shelf period is long, that is, a long period of time is needed from the installation and use of IT servers and other types of equipment in the data center to the gradual loading of IT equipment. The refrigeration capacity of the data center configured room air conditioner is generally configured according to the full power of the room IT equipment, and 10% design margin is also reserved considering the heat leakage of the enclosure structure. Therefore, for the early configuration of the data center room, in the case of little IT equipment loading, the refrigeration capacity of the room air conditioner is much larger than the power of the loaded server. In this case, the air conditioner compressor is prone to frequent start-stop. For the compressor system, each start-stop will generate a large inrush current, which is extremely detrimental to the service life of the compressor, and the air conditioning system supply air temperature is too low, resulting in large fluctuations in the room temperature field. In the case of high environmental humidity, there may even be server condensation and other risks and abnormalities, which adversely affect the long-term stable and reliable operation of the data center IT equipment.

[0003] The existing air conditioning system has the problem of frequent start-stop of the compressor in the application scenario of load disclosure. UTILITY MODEL CONTENT

[0004] In view of the deficiencies of the above-mentioned prior art, the purpose of the utility model is to provide an air conditioning system suitable for low load refrigeration operation, which aims to solve the problem of frequent start-stop of the compressor of the existing air conditioning system in the application scenario of load disclosure.

[0005] The air conditioning system suitable for low load refrigeration operation provided in the application adopts the following technical solution: an air conditioning system suitable for low load refrigeration operation, comprising:

[0006] A first evaporator;

[0007] A second evaporator;

[0008] A compressor;

[0009] A condenser;

[0010] A first connecting pipeline, one end of which is connected to the liquid outlet end of the condenser, and the other end is connected to the liquid inlet end of the first evaporator. A first electronic expansion valve is arranged on the first connecting pipeline, and the first electronic expansion valve is used to adjust the flow of the first connecting pipeline.

[0011] a second connecting pipeline, one end of which is connected with the liquid outlet end of the condenser, and the other end of which is connected with the liquid inlet end of the second evaporator, a second electronic expansion valve being arranged on the second connecting pipeline, the second electronic expansion valve being used for adjusting the flow of the second connecting pipeline;

[0012] a third connecting pipeline, one end of which is connected with the gas outlet end of the first evaporator and the gas outlet end of the second evaporator respectively, and the other end of which is connected with the gas inlet end of the compressor;

[0013] a fourth connecting pipeline, one end of which is connected with the gas outlet end of the compressor, and the other end of which is connected with the condenser;

[0014] a control element, which is electrically connected with the first electronic expansion valve and the second electronic expansion valve respectively.

[0015] Optionally, the air conditioning system suitable for low-load refrigeration operation comprises:

[0016] a fifth connecting pipeline, one end of which is connected with the fourth connecting pipeline, and the other end of which is connected with the first connecting pipeline between the first evaporator and the first electronic expansion valve, a hot gas bypass electromagnetic valve being arranged on the fifth connecting pipeline, the hot gas bypass electromagnetic valve being used for guiding part of gaseous condensing agent into the first connecting pipeline;

[0017] the control element is electrically connected with the hot gas bypass electromagnetic valve.

[0018] Optionally, the air conditioning system suitable for low-load refrigeration operation comprises an air conditioner indoor unit shell, a containing space being arranged in the air conditioner indoor unit shell, the first evaporator, the second evaporator, the first electronic expansion valve, the second electronic expansion valve, the compressor and the hot gas bypass electromagnetic valve being arranged in the containing space.

[0019] Optionally, the air conditioning system suitable for low-load refrigeration operation comprises a return air temperature sensor.

[0020] The return air temperature sensor is arranged in a return air area of the containing space, the return air temperature sensor being used for collecting a return air temperature value of the return air area, and the return air temperature sensor being electrically connected with the control element.

[0021] Optionally, the return air temperature sensor is provided with at least two, and the at least two return air temperature sensors are arranged at different heights.

[0022] Optionally, the air conditioning system suitable for low-load refrigeration operation comprises a supply air temperature sensor.

[0023] The air supply temperature sensor is arranged in an air supply area of the accommodation space, and is used to collect an air supply temperature value of the air supply area.

[0024] Optionally, the air conditioning system suitable for low-load refrigeration operation comprises a low-pressure sensor arranged on the third connecting pipeline, and used to detect a low-pressure value of the air conditioning system suitable for low-load refrigeration operation.

[0025] Optionally, the air conditioning system suitable for low-load refrigeration operation comprises a first suction temperature sensor and a second suction temperature sensor, the first suction temperature sensor is arranged close to the first evaporator, and the second suction temperature sensor is arranged close to the second evaporator, the first suction temperature sensor is used to detect a suction temperature of the first evaporator, and the second suction temperature sensor is used to detect a suction temperature of the second evaporator.

[0026] Optionally, the first evaporator and the second evaporator are symmetrically distributed in the accommodation space.

[0027] Optionally, the air conditioning system suitable for low-load refrigeration operation comprises a sixth connecting pipeline, one end of the sixth connecting pipeline is connected with one end of the first connecting pipeline and one end of the second connecting pipeline, respectively, and the other end of the sixth connecting pipeline is connected with a liquid discharge end of the condenser.

[0028] The sixth connecting pipeline is provided with a drying filter.

[0029] Compared with the prior art, the embodiments of the utility model have the following advantages:

[0030] When the air conditioning system suitable for low-load refrigeration operation is working, the first electronic expansion valve is preferentially opened, and the temperature is lowered through the flow path in which the first evaporator is arranged first, when the operating frequency of the compressor is greater than the opening frequency of the electronic expansion valve, it is indicated that the air conditioning system suitable for low-load refrigeration operation is insufficient to stabilize the temperature of the machine room by only opening the first electronic expansion valve and outputting refrigerating capacity by the first evaporator, the control member controls the second electronic expansion valve to be opened, and the flow path in which the second evaporator is arranged is increased to improve the temperature, and the switching of one refrigeration flow path and two refrigeration flow paths is realized through the starting and closing of the first electronic expansion valve and the second electronic expansion valve, so that the data center machine room can still be kept stable refrigeration operation in a low-load application occasion, the abnormal fluctuation of the temperature field of the machine room caused by the frequent start-stop of the compressor is avoided, and the compressor failure rate is effectively reduced. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to make the technical personnel in the technical field better understand the present application scheme, the following will be combined with the drawings in the embodiments of the present application, the technical scheme in the embodiments of the present application is described clearly and completely, obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the ordinary skilled in the art without creative labor are within the scope of protection of the present application.

[0032] Figure 1 It is the overall structure schematic diagram of the air conditioning system suitable for low load refrigeration operation in the embodiment of the present application.

[0033] Mark explanation:

[0034] 1, first evaporator;2, second evaporator;3, compressor;4, condenser;5, first electronic expansion valve;6, second electronic expansion valve;7, first connecting pipeline;8, second connecting pipeline;9, third connecting pipeline;10, fourth connecting pipeline;11, fifth connecting pipeline;12, hot gas bypass solenoid valve;13, return air temperature sensor;14, supply air temperature sensor;15, low pressure sensor;16, first suction temperature sensor;17, second suction temperature sensor;18, sixth connecting pipeline;19, dry filter;20, high pressure sensor. Specific implementation

[0035] In order to make the technical personnel in the technical field better understand the present application scheme, the following will be combined with the drawings in the embodiments of the present application, the technical scheme in the embodiments of the present application is described clearly and completely, obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the ordinary skilled in the art without creative labor are within the scope of protection of the present application.

[0036] The present application is further described in detail below in conjunction with the drawings of the specification.

[0037] The embodiment of the present application discloses an air conditioning system suitable for low load refrigeration operation.

[0038] As Figure 1As shown, an air conditioning system suitable for low-load refrigeration operation includes a first evaporator 1, a second evaporator 2, a compressor 3, a condenser 4, a first connecting pipeline 7, a second connecting pipeline 8, a third connecting pipeline 9, a fourth connecting pipeline 10, and a control member; one end of the first connecting pipeline 7 is connected with the liquid outlet end of the condenser 4, and the other end is connected with the liquid inlet end of the first evaporator 1, and the first connecting pipeline 7 is provided with a first electronic expansion valve 5, and the first electronic expansion valve 5 is used to adjust the flow of the first connecting pipeline 7; one end of the second connecting pipeline 8 is connected with the liquid outlet end of the condenser 4, and the other end is connected with the liquid inlet end of the second evaporator 2, and the second connecting pipeline 8 is provided with a second electronic expansion valve 6, and the second electronic expansion valve 6 is used to adjust the flow of the second connecting pipeline 8; one end of the third connecting pipeline 9 is connected with the exhaust end of the first evaporator 1 and the exhaust end of the second evaporator 2 respectively, and the other end is connected with the air inlet end of the compressor 3; one end of the fourth connecting pipeline 10 is connected with the exhaust end of the compressor 3, and the other end is connected with the condenser 4; and the control member is electrically connected with the first electronic expansion valve 5 and the second electronic expansion valve 6 respectively.

[0039] When the air conditioning system suitable for low-load refrigeration operation is working, the first electronic expansion valve 5 is opened first, and the cooling work is performed through the flow path where the first evaporator 1 is located; when the operating frequency of the compressor 3 is greater than the opening frequency of the electronic expansion valve (including the first electronic expansion valve 5 and the second electronic expansion valve 6), it indicates that the cooling capacity output by the first evaporator 1 is insufficient to stabilize the temperature of the machine room, and the control member controls the second electronic expansion valve 6 to be opened to increase the flow path where the second evaporator 2 is located to improve the temperature reduction; the switching between one refrigeration flow path and two refrigeration flow paths is realized through the starting and stopping of the first electronic expansion valve 5 and the second electronic expansion valve 6, the stable refrigeration operation of the data center machine room in the low-load application occasion can be continuously maintained, and the abnormal fluctuation of the temperature field of the machine room caused by the frequent start-stop problem of the compressor 3 is avoided, and the failure rate of the compressor 3 is effectively reduced.

[0040] The air conditioning system suitable for low-load refrigeration operation includes an air conditioner indoor unit shell, a return air temperature sensor 13, and a supply air temperature sensor 14, the air conditioner indoor unit shell is provided with a containing space, the first evaporator 1, the second evaporator 2, the first electronic expansion valve 5, the second electronic expansion valve 6, the compressor 3, the return air temperature sensor 13, and the supply air temperature sensor 14 are all arranged in the containing space. The return air temperature sensor 13 is arranged in the return air area of the containing space, and is used to collect the return air temperature value of the return air area. The supply air temperature sensor 14 is arranged in the supply air area of the containing space, and is used to collect the supply air temperature value of the supply air area. The return air temperature sensor 13 and the supply air temperature sensor 14 are electrically connected with the control member respectively.

[0041] Specifically, the air conditioner indoor unit shell can protect the first evaporator 1, the second evaporator 2, the first electronic expansion valve 5, the second electronic expansion valve 6, the compressor 3, the return air temperature sensor 13 and the supply air temperature sensor 14 and other electronic devices in the accommodation space.

[0042] The first evaporator 1 and the second evaporator 2 are symmetrically distributed in the accommodation space, and in this embodiment, the first evaporator 1 and the second evaporator 2 adopt a V-shaped layout form. The flow of the first evaporator 1 is adjusted by the first electronic expansion valve 5, and the flow of the second evaporator 2 is adjusted by the second electronic expansion valve 6, so as to adapt to the circulating flow of the air conditioning system suitable for low-load refrigeration operation, and ensure the normal refrigeration operation of the system.

[0043] The control member is a control panel, and in this embodiment, the model of the control panel selected is XBK01, and the control chip on the control panel is STM32F103.

[0044] The return air area is the return air area of the air conditioner indoor unit, and the return air area is arranged at the return air port of the air conditioner indoor unit shell.

[0045] The supply air area is the supply air area of the air conditioner indoor unit, and the supply air area is arranged at the supply air port of the air conditioner indoor unit shell.

[0046] The return air temperature sensor 13 arranged on the return air area can collect the return air temperature value of the return air area, so as to timely monitor the circulation condition and temperature change of indoor air, so that the air conditioning system suitable for low-load refrigeration operation can better master the overall temperature of indoor air, and ensure that the air conditioning system suitable for low-load refrigeration operation can adjust the temperature according to the outlet air temperature value, and realize more accurate temperature control.

[0047] The outlet air temperature sensor arranged on the outlet air area can collect the outlet air temperature value of the outlet air area, so as to ensure that the air conditioning system suitable for low-load refrigeration operation can adjust the temperature according to the outlet air temperature value.

[0048] Further, the return air temperature sensor 13 is provided with at least two return air temperature sensors 13 arranged at different heights.

[0049] The supply air temperature sensor 14 is provided with at least two supply air temperature sensors 14 arranged at different heights.

[0050] In this embodiment, the return air temperature sensor 13 includes a first return air temperature sensor 13 and a second return air temperature sensor 13.

[0051] The supply air temperature sensor 14 includes a first supply air temperature sensor 14 and a second supply air temperature sensor 14.

[0052] The first return air temperature sensor 13 and the second return air temperature sensor 13 are arranged in the return air zone, and the first supply air temperature sensor 14 and the second supply air temperature sensor 14 are arranged at different heights in the return air zone.

[0053] The height of the return air zone is divided into N equal parts (N is greater than or equal to 2), and the first return air temperature sensor 13 and the second return air temperature sensor 13 are arranged at the height positions of i / N and m / N respectively, wherein i and m are both greater than 0, and i and m are both less than or equal to N, and i and m are not the same.

[0054] In this embodiment, the height of the return air zone is divided into three equal parts, and the first return air temperature sensor 13 and the second return air temperature sensor 13 are arranged at the height positions of 1 / 3 and 2 / 3 respectively.

[0055] The return air temperature values collected by the first return air temperature sensor 13 and the second return air temperature sensor 13 are uploaded to the control for related strategy calculation.

[0056] Similarly, the height of the supply air zone is divided into H equal parts (H is greater than or equal to 2), and the first supply air temperature sensor 14 and the second supply air temperature sensor 14 are arranged at the height positions of a / H and b / H respectively, wherein a and b are both greater than 0, and a and b are both less than or equal to H, and a and b are not the same.

[0057] In this embodiment, the height of the supply air zone is divided into three equal parts, and the first supply air temperature sensor 14 and the second supply air temperature sensor 14 are arranged at the height positions of 1 / 3 and 2 / 3 respectively.

[0058] The supply air temperature values collected by the first supply air temperature sensor 14 and the second supply air temperature sensor 14 are uploaded to the control for related strategy calculation.

[0059] When the air conditioning system suitable for low-load refrigeration operation is working normally, the first supply air temperature sensor 14 and the second supply air temperature sensor 14 normally calculate the average return air temperature value for demand calculation, and when any one of the first supply air temperature sensor 14 and the second supply air temperature sensor 14 fails, the remaining one can be used for demand calculation.

[0060] The supply air temperature sensor 14 can be used as a backup for air conditioning refrigeration demand detection after the return air temperature sensor 13 fails because it is used to detect the supply air temperature value.

[0061] That is, the air conditioning system suitable for low-load refrigeration operation defaults to return air temperature control, and when all the return air temperature sensors 13 fail, it is switched to supply air temperature control.

[0062] The air conditioning system suitable for low-load refrigeration operation comprises a low-pressure sensor 15 arranged on the third connecting pipeline 9, and the low-pressure sensor 15 is used for detecting the low-pressure value of the air conditioning system suitable for low-load refrigeration operation, and the low-pressure sensor 15 is electrically connected with the control device.

[0063] The air conditioning system suitable for low-load refrigeration operation comprises a first suction temperature sensor 16 and a second suction temperature sensor 17, the first suction temperature sensor 16 is arranged close to the first evaporator 1, and the second suction temperature sensor 17 is arranged close to the second evaporator 2, the first suction temperature sensor 16 is used for detecting the suction temperature of the first evaporator 1, and the second suction temperature sensor 17 is used for detecting the suction temperature of the second evaporator 2.

[0064] Specifically, the low-pressure sensor 15 can detect the suction pressure of the compressor 3, the first suction temperature sensor 16 can detect the suction temperature of the first evaporator 1, and the second suction temperature sensor 17 can detect the suction temperature of the second evaporator 2.

[0065] The suction pressure detected by the low-pressure sensor 15 and the suction temperatures detected by the first suction temperature sensor 16 and the second suction temperature sensor 17 can be used to calculate the respective suction superheat degrees of the first evaporator 1 and the second evaporator 2.

[0066] The suction superheat degree satisfies the following formula:

[0067] The suction superheat degree = suction temperature - saturation temperature corresponding to suction pressure.

[0068] The saturation temperature corresponding to the suction pressure can be obtained by consulting the refrigerant property table.

[0069] Then, the control device performs a checking operation by calculating the difference between the respective suction superheat degrees of the first evaporator 1 and the second evaporator 2 and the set superheat degree, and issues the corresponding valve step opening requirement of the first electronic expansion valve 5 and the second electronic expansion valve 6 to adjust the opening degree of the first electronic expansion valve 5 and the second electronic expansion valve 6 in real time, thereby adjusting the refrigerant flow in real time, realizing controllable superheat degree, and ensuring stable refrigeration operation of the air conditioning system under the premise of reasonable superheat degree.

[0070] The air conditioning system suitable for low-load refrigeration operation comprises a fifth connecting pipeline 11, one end of the fifth connecting pipeline 11 is connected with the fourth connecting pipeline 10, the other end is connected with the first connecting pipeline 7 between the first evaporator 1 and the first electronic expansion valve 5, a hot gas bypass electromagnetic valve 12 is arranged on the fifth connecting pipeline 11, and the hot gas bypass electromagnetic valve 12 is used for guiding part of the gaseous condensate into the first connecting pipeline 7. The control device is electrically connected with the hot gas bypass electromagnetic valve 12.

[0071] Specifically, a T-shaped tee assembly is installed on the fourth connecting pipeline 10, and the fifth connecting pipeline 11 is a bypass pipeline of the T-shaped tee assembly. One end of the fifth connecting pipeline 11 communicates with the T-shaped tee assembly, and the other end communicates with the first connecting pipeline 7 between the first evaporator 1 and the first electronic expansion valve 5.

[0072] A hot gas bypass solenoid valve 12 is installed on the fourth connecting pipeline 10, and the hot gas bypass solenoid valve 12 is electrically connected with the control member. The main function of the hot gas bypass solenoid valve 12 is to bypass part of the high-temperature gaseous refrigerant from the exhaust end of the compressor 3 to the first connecting pipeline 7 after the first electronic expansion valve 5 according to the demand, and mix with the low-temperature and low-pressure gas-liquid two-phase refrigerant before entering the first evaporator 1, so as to preferentially consume part of the refrigeration capacity before entering the first evaporator 1, so as to increase the temperature of the gas-liquid two-phase refrigerant entering the first evaporator 1, thereby reducing the heat exchange temperature difference between the return air circulation flow in the machine room and the circulating refrigerant in the evaporator, and effectively reducing the heat exchange output of the evaporator coil.

[0073] The air conditioning system suitable for low-load refrigeration operation includes a sixth connecting pipeline 18. One end of the sixth connecting pipeline 18 is connected with one end of the first connecting pipeline 7 and one end of the second connecting pipeline 8 connected with the condenser 4, and the other end is connected with the liquid discharge end of the condenser 4. A drying filter 19 is arranged on the sixth connecting pipeline 18.

[0074] Specifically, the condenser 4 will generate low-temperature and low-pressure gas-liquid two-phase refrigerant, which will be introduced into the first connecting pipeline 7 and the second connecting pipeline 8 through the sixth connecting pipeline 18, and finally enter the corresponding first evaporator 1 and second evaporator 2 through the first electronic expansion valve 5 and the second electronic expansion valve 6.

[0075] The drying filter 19 arranged on the sixth connecting pipeline 18 can filter the residual impurities in the low-temperature and low-pressure gas-liquid two-phase refrigerant, absorb the residual water and acid in the low-temperature and low-pressure gas-liquid two-phase refrigerant, prevent the pipeline from rusting and the decomposition of oil and low-temperature and low-pressure gas-liquid two-phase refrigerant, prevent the motor from burning out, filter impurities and particles, reduce the wear of the compressor 3, and prolong the service life of the compressor 3.

[0076] A high-pressure sensor 20 is arranged on the sixth connecting pipeline 18, and the high-pressure sensor 20 is used for detecting the high-pressure value of the air conditioning system suitable for low-load refrigeration operation. The high-pressure sensor 20 is electrically connected with the control member.

[0077] Specifically, the main function of the high-pressure sensor 20 is to monitor and adjust the pressure in the air conditioning system suitable for low-load refrigeration operation, so as to ensure the safe operation and optimal performance of the system.

[0078] The high pressure sensor 20 senses the refrigerant pressure value (i.e. high pressure value) of the air conditioning system suitable for low load refrigeration operation and transmits the value to the controller, which can adjust the operation state of the air conditioner in time according to the refrigerant pressure value.

[0079] In summary, the overall regulation process of the air conditioning system suitable for low load refrigeration operation is as follows:

[0080] S100, when the electronic expansion valve meets the valve step opening requirement, first open the first electronic expansion valve 5 alone, and perform cooling work through the single operation of the first evaporator 1.

[0081] The valve step opening requirement is that when the air conditioning return air temperature is greater than the air conditioning refrigeration set value + set deviation, it is defined as 100% refrigeration requirement; when the air conditioning return air temperature is less than the air conditioning refrigeration set value - set deviation, it is defined as 0% refrigeration requirement, wherein the set deviation is greater than or equal to 1 degree Celsius (℃) and less than or equal to 10℃, and the default value is 3℃.

[0082] S200, the controller calculates the operating frequency (H) of the compressor 3 in real time, when H is greater than the opening valve frequency of the electronic expansion valve (the opening valve frequency is greater than or equal to 30 hertz (Hz) and less than or equal to 120 Hz, and the default value is 60 Hz), and the duration is T (the value of T is greater than or equal to 1 second and less than or equal to 360 seconds, and the default value of T is 60 seconds), it means that the air conditioning system suitable for low load refrigeration operation only opens the first electronic expansion valve 5 at this time, and the refrigeration capacity output by the first evaporator 1 is not enough to stabilize the temperature of the machine room at this time, so the controller controls the second electronic expansion valve 6 to open, so that the first evaporator 1 and the second evaporator 2 work together.

[0083] It should be noted that when the first electronic expansion valve 5 is opened, if the air conditioning return air temperature ≥ air conditioning refrigeration set value + set deviation, and the duration is 0.5T, it means that the IT load of the machine room is large at this time, so the second electronic expansion valve 6 can be opened without detecting whether H is greater than the opening valve frequency of the electronic expansion valve.

[0084] S300, when the first electronic expansion valve 5 and the second electronic expansion valve 6 are both opened, if the air conditioning return air temperature < air conditioning refrigeration set value - set deviation * electronic expansion valve closing temperature ratio (the value of the electronic expansion valve closing temperature ratio is greater than or equal to 1% and less than or equal to 100%, and the default value is 60%), at this time, the return air temperature decreases, and after 10 seconds, the second electronic expansion valve 6 is controlled to be closed.

[0085] Further, if H is less than the electronic expansion valve closing valve frequency (the electronic expansion valve closing valve frequency is greater than or equal to 30 HZ and less than or equal to 120 HZ, and the default value is 50 HZ), and the duration is T, the second electronic expansion valve 6 is controlled to be closed.

[0086] S400, if the second electronic expansion valve 6 is in the closed state, at this time, the air conditioner return air temperature is still < air conditioner refrigeration set value - set deviation * electronic expansion valve closing valve temperature ratio, and the duration is T, it is explained that only the refrigeration capacity generated by opening the first evaporator 1 is still greater than the heat load of the machine room, resulting in the continuous decrease of the air conditioner return air temperature, in order to protect the compressor 3 from stopping due to the decrease of the temperature to the stop value, at this time, the control panel will issue an opening instruction of the hot gas bypass electromagnetic valve 12, and the hot gas bypass electromagnetic valve 12 is opened.

[0087] When the hot gas bypass electromagnetic valve 12 is opened, the temperature of the gas-liquid two-phase refrigerant entering the first evaporator 1 will be increased, the refrigeration capacity output of the first evaporator 1 will be reduced, that is, the air conditioner return air temperature difference will be effectively reduced, and the return air temperature of the air conditioner system suitable for low load refrigeration operation will not be continuously reduced to the stop value, so that the return air temperature of the air conditioner indoor unit is relatively stable. When the H of the air conditioner compressor 3 is greater than the opening valve frequency of the electronic expansion valve, and the duration is T, it is explained that the machine room load has been improved, and then the hot gas bypass electromagnetic valve 12 is closed.

[0088] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0089] It should be noted that the present application introduces the specific structure and working principle of the present application by taking an air conditioning system suitable for low load refrigeration operation as an example, but the application of the present application is not limited to an air conditioning system suitable for low load refrigeration operation, and can also be applied to the production and use of other similar workpieces.

[0090] It should be understood that the present application is not limited to the precise structures described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present application is only limited by the appended claims.

[0091] The above is only a preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application. The above is only a preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. An air conditioning system suitable for low load refrigeration operation, characterized by, Comprise: A first evaporator; A second evaporator; A compressor; A condenser; A first connecting pipeline, one end of which is connected with a liquid outlet end of the condenser, and the other end of which is connected with a liquid inlet end of the first evaporator, a first electronic expansion valve being arranged on the first connecting pipeline, the first electronic expansion valve being used for adjusting the flow of the first connecting pipeline; A second connecting pipeline, one end of which is connected with the liquid outlet end of the condenser, and the other end of which is connected with the liquid inlet end of the second evaporator, a second electronic expansion valve being arranged on the second connecting pipeline, the second electronic expansion valve being used for adjusting the flow of the second connecting pipeline; A third connecting pipeline, one end of which is connected with an exhaust end of the first evaporator and an exhaust end of the second evaporator respectively, and the other end of which is connected with an air inlet end of the compressor; A fourth connecting pipeline, one end of which is connected with an exhaust end of the compressor, and the other end of which is connected with the condenser; a control element being electrically connected with the first electronic expansion valve and the second electronic expansion valve respectively; The air conditioning system suitable for low-load refrigeration operation comprises a fifth connecting pipeline, one end of which is connected with the fourth connecting pipeline, and the other end of which is connected with the first connecting pipeline between the first evaporator and the first electronic expansion valve, a hot gas bypass electromagnetic valve being arranged on the fifth connecting pipeline, the hot gas bypass electromagnetic valve being used for guiding part of gaseous condensate into the first connecting pipeline; The control element is electrically connected with the hot gas bypass electromagnetic valve; The air conditioning system suitable for low-load refrigeration operation comprises an air conditioner indoor unit shell, a containing space being arranged in the air conditioner indoor unit shell, the first evaporator, the second evaporator, the first electronic expansion valve, the second electronic expansion valve, the compressor and the hot gas bypass electromagnetic valve being arranged in the containing space; The air conditioning system suitable for low-load refrigeration operation comprises a return air temperature sensor; The return air temperature sensor is arranged in a return air area of the containing space, the return air temperature sensor being used for collecting a return air temperature value of the return air area, and the return air temperature sensor being electrically connected with the control element; The return air temperature sensor is provided with at least two, and the at least two return air temperature sensors are arranged at different heights.

2. The air conditioning system according to claim 1, wherein The air conditioning system suitable for low-load refrigeration operation comprises a supply air temperature sensor; The supply air temperature sensor is arranged in a supply air area of the containing space, the supply air temperature sensor being used for collecting a supply air temperature value of the supply air area, and the supply air temperature sensor being electrically connected with the control element.

3. The air conditioning system according to claim 1, wherein The air conditioning system suitable for low-load refrigeration operation comprises a low-pressure sensor, the low-pressure sensor being arranged on the third connecting pipeline, the low-pressure sensor being used for detecting a low-pressure value of the air conditioning system suitable for low-load refrigeration operation, and the low-pressure sensor being electrically connected with the control element.

4. The air conditioning system according to claim 3, wherein The air conditioning system suitable for low-load refrigeration operation comprises a first suction temperature sensor and a second suction temperature sensor, the first suction temperature sensor is arranged close to the first evaporator, the second suction temperature sensor is arranged close to the second evaporator, the first suction temperature sensor is used for detecting the suction temperature of the first evaporator, and the second suction temperature sensor is used for detecting the suction temperature of the second evaporator.

5. The air conditioning system according to claim 1, wherein The first evaporator and the second evaporator are symmetrically distributed in the accommodation space.

6. The air conditioning system suitable for low load refrigeration operation according to claim 1, wherein The air conditioning system suitable for low-load refrigeration operation comprises a sixth connecting pipeline, one end of the sixth connecting pipeline is connected with one end of the first connecting pipeline connected with the condenser and one end of the second connecting pipeline connected with the condenser respectively, and the other end is connected with a liquid discharge end of the condenser. A drying filter is arranged on the sixth connecting pipeline.

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