Aircraft ground air conditioning and control method thereof

Abstract

The present application relates to the technical field of aircraft ground air conditioning, and in particular to an aircraft ground air conditioning and a control method thereof. The aircraft ground air conditioning comprises a first-stage refrigeration system, a second-stage refrigeration system and an air supply device, at least part of the first-stage refrigeration system is arranged close to the air inlet side of the air supply device, the second-stage refrigeration system is arranged away from the air inlet side of the air supply device, and a dew point temperature sensor is arranged at the air inlet of the air supply device for detecting the dew point temperature of the air after being refrigerated by the first-stage refrigeration system; the refrigeration capacity of the first-stage refrigeration system is adjustable so that the dew point temperature is within a set range, and the moisture content of the air entering the second-stage refrigeration system is reduced, so as to achieve the purpose of controlling temperature and humidity and delaying frosting, and can effectively reduce the risk of water in the air supply.

Description

Technical Field

[0001] The present application relates to the technical field of aircraft ground air conditioning, and in particular to an aircraft ground air conditioning and a control method thereof. Background Art

[0002] Aircraft ground air conditioners are connected to aircraft through air supply hoses to supply air to the aircraft to adjust the cabin environment. They are fresh air and low supply temperature air conditioning units. Civil aviation standards stipulate that the air supply temperature of the unit is lower than 2°C. At this time, the temperature of the evaporator is lower than 0°C. Frosting will inevitably occur on the evaporator. Operation with frost will cause the refrigeration system to have a lower operating efficiency and a worsening refrigeration effect. Therefore, frequent defrosting is required. The water mist or water droplets generated after defrosting can easily enter the air supply hose, increasing the difficulty of retracting and releasing the air duct, and making it more susceptible to wear. At the same time, residual condensed water accumulated in the air supply hose is prone to mildew, increasing the workload of equipment maintenance. Summary of the invention

[0003] The purpose of the present application is to provide an aircraft ground air conditioner and a control method thereof, so as to reduce the moisture content of humid air, delay frosting, and reduce the risk of water in the air supply while ensuring that the air supply temperature of the air conditioner meets the specified requirements.

[0004] Based on the above purpose, the present application provides an aircraft ground air conditioner, including a first-stage refrigeration system, a second-stage refrigeration system and an air supply device, wherein at least a portion of the first-stage refrigeration system is arranged close to the air inlet side of the air supply device, and the second-stage refrigeration system is arranged away from the air inlet side of the air supply device, and a dew point temperature sensor is arranged at the air inlet of the air supply device for detecting the dew point temperature of air after being cooled by the first-stage refrigeration system; the refrigeration capacity of the first-stage refrigeration system is adjustable so that the dew point temperature is within a set range and the moisture content of the air entering the second-stage refrigeration system is reduced.

[0005] In one embodiment of the present application, the first-stage refrigeration system includes a first evaporator and a second evaporator, the first evaporator is located on the air inlet side of the air supply device, the second evaporator is located on the air outlet side of the air supply device, and the evaporator of the second-stage refrigeration system is located on the side of the second evaporator away from the air supply device;

[0006] The aircraft ground air conditioner further includes a refrigerant distributor, which is capable of adjusting the flow of the refrigerant in the first evaporator and the second evaporator so that the refrigeration capacity of the first-stage refrigeration system is adjustable.

[0007] In one embodiment of the present application, the first-stage refrigeration system includes a compressor, and the compressor is a variable frequency compressor, so that the refrigeration capacity of the first-stage refrigeration system is adjustable.

[0008] In one embodiment of the present application, the refrigerant distributor is configured to allow at least part of the refrigerant to flow to the first evaporator when the dew point temperature is greater than a set value;

[0009] The refrigerant distributor is further configured to allow all the refrigerant to flow to the second evaporator when the dew point temperature is equal to or lower than a set value.

[0010] In one embodiment of the present application, the refrigerant distributor is a three-way valve, the opening of the three-way valve is L, and the difference between the dew point temperature and the set value is dt, wherein:

[0011] When 0℃<dt<5℃, L=k·dt×100%; k is the proportionality coefficient;

[0012] When dt≥5°C, the opening degree of the three-way valve is 100%, and all the refrigerant flows to the first evaporator;

[0013] When dt≤0°C, the opening degree of the three-way valve is 0, and all the refrigerant flows to the second evaporator.

[0014] In one embodiment of the present application, a water retaining portion is provided on the air outlet side of the first evaporator, and the water retaining portion is provided with a ventilation structure.

[0015] In one embodiment of the present application, the water retaining portion is a plate-like structure, and the ventilation structure includes a plurality of ventilation holes arranged in the plate-like structure.

[0016] In one embodiment of the present application, the water retaining portion is a louver structure, and the ventilation structure is a gap between two adjacent blades of the louver structure.

[0017] In one embodiment of the present application, the refrigeration capacity of the second-stage refrigeration system is adjustable.

[0018] In one embodiment of the present application, the aircraft ground air conditioner further includes a precooling system, and the precooling system is located on a side of the first-stage refrigeration system away from the air supply device.

[0019] In one embodiment of the present application, the aircraft ground air conditioner further comprises an air supply passage, wherein the air supply device, the evaporator of the second-stage refrigeration system, the first evaporator and the second evaporator are all located in the air supply passage;

[0020] An ambient temperature sensor is disposed at the inlet of the air supply channel, and an air outlet temperature sensor is disposed at the outlet of the air supply channel.

[0021] Based on the above purpose, the present application also provides a control method for an aircraft ground air conditioner, the control method for an aircraft ground air conditioner is applied to the aircraft ground air conditioner, and the control method for an aircraft ground air conditioner comprises the following steps:

[0022] Adjust the cooling capacity of the first-stage refrigeration system so that the outlet dew point temperature of the first-stage refrigeration system is within the set range and the moisture content of the air entering the second-stage refrigeration system is reduced.

[0023] In one embodiment of the present application, the control method of the aircraft ground air conditioner further includes the following steps:

[0024] The refrigerant distributor adjusts the flow of the refrigerant in the first evaporator and the second evaporator according to the dew point temperature detected by the dew point temperature sensor, wherein when the dew point temperature is greater than a set value, the refrigerant distributor causes at least part of the refrigerant to flow to the first evaporator;

[0025] When the dew point temperature is equal to or lower than a set value, the refrigerant distributor allows all the refrigerant to flow to the second evaporator.

[0026] In one embodiment of the present application, the difference between the dew point temperature and the set value is dt, where:

[0027] When 0°C<dt<5°C, part of the refrigerant flows to the first evaporator, and the other part flows to the second evaporator;

[0028] When dt≥5°C, all the refrigerant flows to the first evaporator;

[0029] When dt≤0°C, all the refrigerant flows to the second evaporator.

[0030] The beneficial effects of this application are mainly:

[0031] The aircraft ground air conditioner provided by the present application comprises a first-stage refrigeration system, a second-stage refrigeration system and an air supply device, wherein at least a portion of the first-stage refrigeration system is arranged close to the air inlet side of the air supply device, and the second-stage refrigeration system is arranged away from the air inlet side of the air supply device, and a dew point temperature sensor is arranged at the air inlet of the air supply device for detecting the dew point temperature of the air after being refrigerated by the first-stage refrigeration system; the refrigeration capacity of the first-stage refrigeration system is adjustable so as to make the dew point temperature within a set range and reduce the moisture content of the air entering the second-stage refrigeration system. Based on this structure, when the aircraft ground air conditioner provided by the present application is in use, the air passes through the first-stage refrigeration system and the second-stage refrigeration system in sequence, and through the refrigeration effect of the second-stage refrigeration system and the adjustment of the refrigeration capacity of the first-stage refrigeration system, the dew point temperature of the air can be adjusted on the premise that the air supply temperature meets the specified requirements, thereby reducing the moisture content of the air entering the second-stage refrigeration system, achieving the purpose of controlling temperature and humidity and delaying frosting, and can effectively reduce the risk of air duct mildew caused by water in the air supply, and at the same time, can reduce the difficulty of retracting and extending the air duct and the degree of wear of the air duct, and reduce the workload of equipment maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 A schematic diagram of the structure of an aircraft ground air conditioner provided in an embodiment of the present application;

[0034] Figure 2 Another structural schematic diagram of an aircraft ground air conditioner provided in an embodiment of the present application;

[0035] Figure 3 A graph showing the change in air state during the cooling process of the aircraft ground air conditioning;

[0036] Figure 4 A flow chart of a method for controlling an aircraft ground air conditioner provided in an embodiment of the present application;

[0037] Figure 5 Another flow chart of a method for controlling an aircraft ground air conditioner provided in an embodiment of the present application.

[0038] The following are the descriptions of the reference numerals:

[0039] 100-first stage refrigeration system; 101-first evaporator; 102-second evaporator; 103-first stage compressor; 104-first stage condenser; 200-second stage refrigeration system; 201-second stage compressor; 202-second stage condenser; 203-second stage evaporator; 300-dew point temperature sensor; 400-air supply equipment; 500-refrigerant distributor; 600-air supply channel; 601-ambient temperature sensor; 602-air outlet temperature sensor; 700-precooling system; 800-water retaining part. DETAILED DESCRIPTION

[0040] The technical solution of the present application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0041] In the description of the present application, it should be noted that if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, if the terms "first", "second", "third" appear, they are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0042] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0043] See also Figures 1 to 3As shown, this embodiment provides an aircraft ground air conditioner, including a first-stage refrigeration system 100, a second-stage refrigeration system 200 and an air supply device 400. At least part of the first-stage refrigeration system 100 is arranged close to the air inlet side of the air supply device 400, and the second-stage refrigeration system 200 is arranged away from the air inlet side of the air supply device 400. A dew point temperature sensor 300 is arranged at the air inlet of the air supply device for detecting the dew point temperature of the air after being refrigerated by the first-stage refrigeration system 100. The refrigeration capacity of the first-stage refrigeration system 100 is adjustable so that the dew point temperature is within a set range and the moisture content of the air entering the second-stage refrigeration system 200 is reduced.

[0044] The aircraft ground air conditioner is a fresh air unit. The air intake of the unit is the outdoor ambient air, and the outdoor air temperature is variable. When the outdoor air temperature is low, for example, when the outdoor air temperature changes from 35°C to 25°C, the load of the unit is low. The civil aviation standard stipulates that the air supply temperature of the unit is lower than 2°C. At this time, the temperature of the evaporator in the second-stage refrigeration system of the aircraft ground air conditioner is lower than 0°C, and frosting is inevitable; because the air outlet pressure of the unit is as high as 5000Pa or more, the air will have a temperature rise of 5 to 12°C after passing through the air supply equipment. When the fresh air load is low, the first-stage refrigeration system will invest too much cooling capacity and the evaporator will also frost. By reducing the humidity content of the air, the frosting of the evaporator can be alleviated. Therefore, this embodiment adjusts the cooling capacity invested in the refrigeration system based on the dew point temperature to control the humidity content of the air.

[0045] When the aircraft ground air conditioner provided by this embodiment is in use, air passes through the first-stage refrigeration system 100 and the second-stage refrigeration system 200 in sequence. Through the refrigeration effect of the second-stage refrigeration system 200 and the adjustment of the refrigeration capacity of the first-stage refrigeration system 100, the dew point temperature of the air can be adjusted on the premise that the supply air temperature meets the specified requirements, thereby reducing the moisture content of the air entering the second-stage refrigeration system 200, achieving the purpose of controlling temperature and humidity and delaying frosting, and can effectively reduce the risk of air duct mildew caused by water in the supply air. At the same time, it can reduce the difficulty of retracting and extending the air duct and the degree of wear of the air duct, thereby reducing the workload of equipment maintenance.

[0046] See also Figure 1 As shown, the first-stage refrigeration system 100 includes a first evaporator 101 and a second evaporator 102, the first evaporator 101 is located at the air inlet side of the air supply device 400, the second evaporator 102 is located at the air outlet side of the air supply device 400, and the evaporator of the second-stage refrigeration system 200 is located at the side of the second evaporator 102 away from the air supply device 400. Exemplarily, the air supply device 400 can be a blower, under the action of the blower, the air in the external environment flows along the arrow direction M.

[0047] The aircraft ground air conditioner further comprises a refrigerant distributor 500 which is capable of adjusting the flow rate of the refrigerant in the first evaporator 101 and the second evaporator 102 so that the dew point temperature of the air passing through the first evaporator 101 is within a set range and the moisture content of the air entering the second-stage refrigeration system 200 is reduced.

[0048] The dehumidification function of the evaporator is achieved through refrigeration and cooling. The air passing through the evaporator is cooled. When the temperature is lower than the dew point temperature of the air, the moisture in the air will precipitate. By adjusting the refrigerant flow ratio in the first evaporator and the second evaporator, the refrigeration capacity of the first-stage refrigeration system is actually adjusted, thereby achieving the purpose of adjusting the humidity of the air after cooling through the first evaporator.

[0049] In one embodiment, see Figure 1 As shown, the first-stage refrigeration system 100 also includes a first-stage compressor 103 and a first-stage condenser 104. The air outlet of the first-stage compressor 103 is connected to the inlet of the first-stage condenser 104, and the outlet of the first-stage condenser 104 is connected to the refrigerant distributor 500. The refrigerant distributor 500 is connected to the inlet of the first evaporator 101 and the inlet of the second evaporator 102 respectively, and the outlet of the first evaporator 101 and the outlet of the second evaporator 102 are connected to the return air port of the first-stage compressor 103.

[0050] The setting range of dew point temperature is -10~10℃.

[0051] In other embodiments, when the first-stage compressor 103 is a variable frequency compressor, the cooling capacity of the first-stage refrigeration system can be adjusted. At this time, the number of evaporators in the first-stage refrigeration system 100 is one, and the evaporator is located on the air inlet side of the air supply device.

[0052] The second-stage refrigeration system 200 includes a second-stage compressor 201, a second-stage condenser 202 and a second-stage evaporator 203. The air outlet of the second-stage compressor 201 is connected to the inlet of the second-stage condenser 202, the outlet of the second-stage condenser 202 is connected to the inlet of the second-stage evaporator 203, and the outlet of the second-stage evaporator 203 is connected to the return air port of the second-stage compressor 201.

[0053] In order to better ensure that the air outlet temperature meets the requirements, the cooling capacity of the second-stage refrigeration system is adjustable.

[0054] See also Figure 1As shown, the aircraft ground air conditioner also includes an air supply channel 600, and the air supply device 400, the second-stage evaporator 203, the first evaporator 101 and the second evaporator 102 are all located in the air supply channel 600; the inlet of the air supply channel 600 is provided with an ambient temperature sensor 601, which is used to detect the temperature of the air in the environment, and the outlet of the air supply channel 600 is provided with an outlet temperature sensor 602, which is used to detect the temperature of the air after being cooled by the aircraft ground air conditioner. Under the action of the air blower, the air in the external environment enters the air supply channel 600 along the arrow direction M, and after being cooled by the first evaporator 101, the second evaporator 102 and the second-stage evaporator 203, it enters the aircraft from the outlet of the air supply channel 600 to cool the interior of the aircraft.

[0055] In one embodiment, see Figure 2 As shown, the aircraft ground air conditioner further includes a precooling system 700 , which is located on a side of the first-stage refrigeration system 100 away from the air inlet side of the air supply device 400 .

[0056] The precooling system 700 can precool the ambient air to achieve multi-stage cooling, thereby further improving the refrigeration efficiency and refrigeration effect of the aircraft ground air conditioning.

[0057] The structure of the pre-cooling system 700 is substantially the same as that of the second-stage refrigeration system. The evaporator of the pre-cooling system 700 is also located in the air supply channel 600 .

[0058] There may be more than one pre-cooling system 700. The pre-cooling system 700, the first-stage refrigeration system 100 and the second-stage refrigeration system 200 are all independent cooling systems.

[0059] The precooling system 700, the first stage refrigeration system 100 and the second stage refrigeration system 200 are arranged in sequence along the arrow direction M. Usually, the refrigeration capacity of the precooling system 700, the first stage refrigeration system 100 and the second stage refrigeration system 200 gradually decreases. Of course, there may also be a situation where the refrigeration capacity of at least the two is the same.

[0060] See also Figure 2 As shown, the aircraft ground air conditioner includes a precooling system 700, a first-stage refrigeration system 100 and a second-stage refrigeration system 200. The functions of the precooling system 700 and the first-stage refrigeration system 100 are precooling and humidity adjustment, and the function of the second-stage refrigeration system 200 is deep cooling temperature adjustment. Under the premise of ensuring that the outlet air temperature reaches the set requirement, the unit simultaneously adjusts the dew point temperature of the air after passing through the first evaporator 101 of the first-stage refrigeration system 100, thereby controlling the moisture content of the humid air entering the deep cooling zone, achieving the purpose of delaying frosting and effectively reducing the risk of water in the supplied air.

[0061] When the dew point temperature is lower than the set value, the air humidity has reached the requirement, but frost is likely to form if the temperature is too low. Therefore, the dew point temperature needs to be controlled within a reasonable range. For example, controlling the refrigerant to flow to the second evaporator 102 is to prevent the first evaporator from frosting due to the low air temperature.

[0062] In one embodiment, the refrigerant distributor 500 is configured to make at least part of the refrigerant flow to the first evaporator 101 when the dew point temperature is greater than the set value; the refrigerant distributor 500 is also configured to make all the refrigerant flow to the second evaporator 102 when the dew point temperature is equal to or lower than the set value. Under the premise of meeting the requirements of the outlet air temperature, the refrigerant distributor 500 can adjust different cooling capacity combinations of different refrigeration systems to reduce the moisture content of the humid air entering the second-stage refrigeration system 200, and control the outlet air humidity while controlling the outlet air temperature, so as to delay frosting and effectively reduce the risk of water in the air supply.

[0063] In one embodiment, the refrigerant distributor 500 is a three-way valve. By controlling the opening of the three-way valve, the cooling capacity output is controlled so that the dew point temperature is close to the set value.

[0064] The opening of the three-way valve is L, and dt is the difference between the dew point temperature and the set value. Where:

[0065] When 0℃<dt<5℃, the opening of the three-way valve is calculated according to the formula L=k·dt×100%, which is a dimensionless formula, and k is a proportional coefficient; usually, the value of k is 0.2. For example, when dt=3℃, the opening of the three-way valve is 60%, at which time, the ratio of the refrigerant flow to the first evaporator 101 and the second evaporator 102 is 3:2.

[0066] When dt≥5℃, the opening of the three-way valve is 100%, and all the refrigerant flows to the first evaporator 101, so that the dew point temperature drops to the set range; when dt≤0℃, the opening of the three-way valve is 0, and all the refrigerant flows to the second evaporator 102, so as to reduce the moisture content of the humid air entering the second-stage refrigeration system 200 as much as possible. The second-stage refrigeration system 200 is used to achieve deep cooling and cooling, so that the air outlet temperature of the aircraft ground air conditioner meets the specified requirements.

[0067] In one embodiment, see Figure 1 and Figure 2 As shown, a water retaining portion 800 is provided on the air outlet side of the first evaporator 101, and the water retaining portion 800 is provided with a ventilation structure, which can block water droplets and allow air to circulate, thereby reducing the moisture content of the humid air passing through the evaporator of the second-stage refrigeration system 200 and reducing the probability of frosting on the evaporator.

[0068] In some embodiments, the water retaining part 800 is a plate-like structure, and the ventilation structure includes a plurality of ventilation holes arranged on the plate-like structure. Exemplarily, the water retaining part 800 is installed at the air outlet of the first-stage evaporator through a bracket.

[0069] In other embodiments, the water retaining portion 800 may also be a louver structure, and the ventilation structure is a gap between two adjacent blades of the louver structure.

[0070] The present embodiment further provides a control method for an aircraft ground air conditioner. The control method for an aircraft ground air conditioner provided by the present embodiment is applied to the aircraft ground air conditioner provided by the present embodiment.

[0071] See also Figure 4 As shown, the control method of the aircraft ground air conditioner includes the following steps:

[0072] Step S102, adjusting the refrigeration capacity of the first-stage refrigeration system 100 so that the outlet air dew point temperature of the first evaporator 101 is within a set range and the moisture content of the air entering the second-stage refrigeration system 200 is reduced.

[0073] The control method for the aircraft ground air conditioner provided in this embodiment is applied to the aircraft ground air conditioner provided in this embodiment. The air passes through the first-stage refrigeration system 100 and the second-stage refrigeration system 200 in sequence. By adjusting the refrigeration capacity of the first-stage refrigeration system 100, the outlet air dew point temperature of the first evaporator 101 can be adjusted on the premise that the supply air temperature meets the specified requirements, thereby reducing the moisture content of the air entering the second-stage refrigeration system 200, achieving the purpose of controlling temperature and humidity and delaying frosting, and can effectively reduce the risk of water in the supply air.

[0074] In one embodiment, see Figure 5 As shown, the control method of the aircraft ground air conditioner also includes the following steps:

[0075] Step S101, start the first-stage refrigeration system 100, the second-stage refrigeration system 200 and the air supply equipment.

[0076] Specifically, after the air supply pipe is connected to the air supply interface of the aircraft ground air conditioner, the first-stage refrigeration system 100, the second-stage refrigeration system 200 and the air supply equipment are started, and then the refrigeration capacity of the first-stage refrigeration system 100 is adjusted.

[0077] In this embodiment, the refrigeration capacity of the second-stage refrigeration system 200 is also adjustable.

[0078] In one embodiment, the control method of the aircraft ground air conditioner further comprises the following steps:

[0079] The refrigerant distributor 500 adjusts the flow rate of the refrigerant in the first evaporator 101 and the second evaporator 102 according to the dew point temperature detected by the dew point temperature sensor 300. Among them, when the dew point temperature is greater than the set value, the refrigerant distributor 500 makes at least part of the refrigerant flow to the first evaporator 101; when the dew point temperature is equal to or lower than the set value, the refrigerant distributor 500 makes all the refrigerant flow to the second evaporator 102.

[0080] On the premise of meeting the requirement of the outlet air temperature, the refrigerant distributor 500 can adjust different cooling capacity combinations of different refrigeration systems, reduce the moisture content of the humid air entering the second-stage refrigeration system 200, and control the outlet air humidity while controlling the outlet air temperature, so as to achieve the purpose of delaying frosting and effectively reduce the risk of water-carrying in the air supply.

[0081] Exemplarily, when the first-stage refrigeration system 100 is turned on, the opening degree L of the refrigerant distributor 500 is adjusted to 100%. After the aircraft ground air conditioner runs for 5 s, the dew point temperature is detected, and the difference dt between the dew point temperature and the set value is calculated. If dt < 0°C, the opening degree L of the refrigerant distributor 500 is adjusted to 0; if dt > 5°C, the opening degree L of the refrigerant distributor remains 100%. If 0 < dt < 5°C, the opening degree L of the refrigerant distributor is calculated according to L = k·dt×100%, where k = 0.2.

[0082] If the shutdown signal has not been received, then after the aircraft ground air conditioner runs for another 5 s, the dew point temperature is detected, dt is recalculated, and the opening degree L of the refrigerant distributor 500 is adjusted.

[0083] Repeat this process until the shutdown signal is received, and the first-stage refrigeration system 100, the second-stage refrigeration system 200, and the air supply equipment are shut down.

[0084] It should be noted that the refrigerant distributor is not limited to the three-way valve, and the flow rate of the refrigerant flowing to the first evaporator or the second evaporator does not necessarily correspond one-to-one to the opening degree of the refrigerant distributor.

[0085] When 0°C < dt < 5°C, A% of the refrigerant flows to the first evaporator, A = k'·dt, and (100 - A)% of the refrigerant flows to the second evaporator, where k' = 20.

[0086] When dt ≥ 5°C, all the refrigerant flows to the first evaporator.

[0087] When dt ≤ 0°C, all the refrigerant flows to the second evaporator.

[0088] Figure 3In the figure, curve 1 (shown by a dotted line) is the change of air state during the cooling process using the aircraft ground air conditioner in the prior art. The aircraft ground air conditioner in the prior art includes a two-stage independent refrigeration system and does not control the dew point temperature. The dry-bulb temperature and humidity content corresponding to point A1 are the temperature and humidity content of the external ambient air when it enters the air supply duct 600, the dry-bulb temperature and humidity content corresponding to point B1 are the temperature and humidity content of the air after passing through the first-stage refrigeration system 100, the dry-bulb temperature and humidity content corresponding to point C1 are the temperature and humidity content of the air after passing through the blower, and the dry-bulb temperature and humidity content corresponding to point D1 are the temperature and humidity content of the cooled air at the air outlet of the air supply duct 600.

[0089] Curve 2 (shown by a dotted line) shows the change in the state of air during the cooling process using the aircraft ground air conditioner and the control method thereof provided in this embodiment, wherein the dry-bulb temperature and humidity content corresponding to point A2 are the temperature and humidity content of the external ambient air when it enters the air supply duct 600, the dry-bulb temperature and humidity content corresponding to point B2 are the temperature and humidity content of the air after passing through the first evaporator 101, the dry-bulb temperature and humidity content corresponding to point C2 are the temperature and humidity content of the air after passing through the blower, and the dry-bulb temperature and humidity content corresponding to point D2 are the temperature and humidity content of the cooled air at the air outlet of the air supply duct 600.

[0090] See also Figure 3 As shown, although the aircraft ground air conditioner in the prior art and the aircraft ground air conditioner provided in this embodiment can both control the outlet air temperature below 2°C, it can be seen from curve 2 that at point B2, the temperature and moisture content of the air after passing through the first evaporator 101 are lower, the outlet air dew point temperature is maintained in a lower range, the air moisture content is low, and it is not easy to frost when passing through the second-stage evaporator 203 of the second-stage refrigeration system 200 with a temperature below 0°C. It has a better anti-frost function and effectively reduces the risk of water in the air supply.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An aircraft ground air conditioner, characterized in that: The invention comprises a first-stage refrigeration system, a second-stage refrigeration system and an air supply device, wherein at least a part of the first-stage refrigeration system is arranged close to the air inlet side of the air supply device, and the second-stage refrigeration system is arranged away from the air inlet side of the air supply device, and a dew point temperature sensor is arranged at the air inlet of the air supply device for detecting the dew point temperature of the air after being refrigerated by the first-stage refrigeration system; the refrigeration capacity of the first-stage refrigeration system is adjustable so that the dew point temperature is within a set range and the moisture content of the air entering the second-stage refrigeration system is reduced; The first-stage refrigeration system comprises a first evaporator and a second evaporator, the first evaporator is located at the air inlet side of the air supply device, the second evaporator is located at the air outlet side of the air supply device, and the evaporator of the second-stage refrigeration system is located at a side of the second evaporator away from the air supply device; It also includes a refrigerant distributor, which can adjust the flow of refrigerant in the first evaporator and the second evaporator to make the refrigeration capacity of the first-stage refrigeration system adjustable.

2. The aircraft ground air conditioner according to claim 1, characterized in that: The first-stage refrigeration system comprises a compressor, and the compressor is a variable frequency compressor, so that the refrigeration capacity of the first-stage refrigeration system is adjustable.

3. The aircraft ground air conditioner according to claim 1, characterized in that: The refrigerant distributor is configured to allow at least part of the refrigerant to flow to the first evaporator when the dew point temperature is greater than a set value; The refrigerant distributor is further configured to allow all the refrigerant to flow to the second evaporator when the dew point temperature is equal to or lower than a set value.

4. The aircraft ground air conditioner according to claim 3, characterized in that: The refrigerant distributor is a three-way valve, the opening of the three-way valve is L, and the difference between the dew point temperature and the set value is dt, where: When 0℃<dt<5℃, L=k·dt×100%; k is the proportionality coefficient; When dt≥5°C, the opening degree of the three-way valve is 100%, and all the refrigerant flows to the first evaporator; When dt≤0°C, the opening degree of the three-way valve is 0, and all the refrigerant flows to the second evaporator.

5. The aircraft ground air conditioner according to claim 1, characterized in that: A water retaining portion is provided on the air outlet side of the first evaporator, and the water retaining portion is provided with a ventilation structure.

6. The aircraft ground air conditioner according to claim 5, characterized in that: The water retaining portion is a plate-shaped structure, and the ventilation structure includes a plurality of ventilation holes arranged on the plate-shaped structure; Alternatively, the water retaining portion is a louver structure, and the ventilation structure is a gap between two adjacent blades of the louver structure.

7. The aircraft ground air conditioner according to any one of claims 1 to 6, characterized in that: The refrigeration capacity of the second-stage refrigeration system is adjustable.

8. The aircraft ground air conditioner according to any one of claims 1 to 6, characterized in that: It also includes a pre-cooling system, which is located on a side of the first-stage refrigeration system away from the air supply device.

9. The aircraft ground air conditioner according to claim 1, 3, 4, 5 or 6, characterized in that: Also includes an air supply channel, wherein the air supply device, the evaporator of the second-stage refrigeration system, the first evaporator and the second evaporator are all located in the air supply channel; An ambient temperature sensor is disposed at the inlet of the air supply channel, and an air outlet temperature sensor is disposed at the outlet of the air supply channel.

10. A method for controlling aircraft ground air conditioning, characterized in that: The control method of the aircraft ground air conditioner is applied to the aircraft ground air conditioner according to any one of claims 1 to 9, and the control method of the aircraft ground air conditioner comprises the following steps: Adjust the cooling capacity of the first-stage refrigeration system so that the outlet dew point temperature of the first-stage refrigeration system is within the set range and the moisture content of the air entering the second-stage refrigeration system is reduced; The refrigerant distributor adjusts the flow rate of the refrigerant in the first evaporator and the second evaporator according to the dew point temperature detected by the dew point temperature sensor.

11. The control method of aircraft ground air conditioning according to claim 10, characterized in that: The control method of the aircraft ground air conditioner further comprises the following steps: The refrigerant distributor adjusts the flow of the refrigerant in the first evaporator and the second evaporator according to the dew point temperature detected by the dew point temperature sensor, wherein when the dew point temperature is greater than a set value, the refrigerant distributor causes at least part of the refrigerant to flow to the first evaporator; When the dew point temperature is equal to or lower than a set value, the refrigerant distributor allows all the refrigerant to flow to the second evaporator.

12. The control method of aircraft ground air conditioning according to claim 11, characterized in that: The difference between the dew point temperature and the set point is dt, where: When 0°C<dt<5°C, part of the refrigerant flows to the first evaporator, and the other part flows to the second evaporator; When dt≥5°C, all the refrigerant flows to the first evaporator; When dt≤0°C, all the refrigerant flows to the second evaporator.

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