Heat pump unit of aircraft air conditioner

Abstract

The utility model discloses a heat pump unit of an aircraft air conditioner, which comprises a fixed-frequency compression system, a variable-frequency compression system, a first heat exchanger, a second heat exchanger, a first fan and a second fan, the fixed-frequency compression system comprises a fixed-frequency compressor and a first four-way valve, and the variable-frequency compression system comprises a variable-frequency compressor and a second four-way valve. The second fan is arranged at an air outlet of the aircraft air conditioner, the first fan is arranged at the first heat exchanger, the second fan is arranged at the second heat exchanger, the first heat exchanger is communicated with the second heat exchanger, the first four-way valve and the second four-way valve are both communicated with the first heat exchanger, and the fourth opening and the eighth opening are both communicated with the second heat exchanger. The constant-frequency compression system and the variable-frequency compression system are combined, the actual power output requirement is met by adjusting the frequency of the variable-frequency compression system, unnecessary energy consumption is reduced, and the energy efficiency ratio is increased.

Description

Technical Field

[0001] The utility model relates to the technical field of air conditioning, in particular to a heat pump unit for aircraft air conditioning. Background Art

[0002] At present, aircraft ground air-conditioning units basically adopt direct expansion systems. The core temperature control configuration adopts multiple fixed-frequency scroll compressors + electric heating. In summer, cooling uses compressor graded output control to supply cold air, and in winter, heating uses electric heating output control (graded, thyristor, graded + thyristor) to supply hot air.

[0003] However, the fixed-speed scroll compressor can only be controlled to start and stop, and the corresponding refrigeration system must be the same. In actual applications, due to changes in operating conditions and customer demand temperature, summer cooling is difficult to match the corresponding cooling load demand only through compressor staged output and bypass control, resulting in unstable supply air temperature. At the same time, bypass control uses a cold and hot hedging method, which is also a waste of energy. Winter heating uses electric heating control, which also leads to relatively low energy efficiency. Utility Model Content

[0004] In order to overcome at least one of the defects of the above-mentioned prior art, the utility model provides a heat pump unit for an aircraft air conditioner, which can solve the problem that the prior art adopts multi-stage fixed frequency technology and cannot accurately control the air volume and match the cooling load demand, and the problem that the use of electric heating for heating leads to too low energy efficiency.

[0005] The technical solution adopted by the utility model to solve the problem is:

[0006] A heat pump unit for an aircraft air conditioner, comprising:

[0007] A fixed-frequency compression system, the fixed-frequency compression system comprising a fixed-frequency compressor and a first four-way valve, the first four-way valve having a first opening, a second opening, a third opening and a fourth opening, a water outlet of the fixed-frequency compressor being connected to the first opening, and a water return port of the fixed-frequency compressor being connected to the third opening;

[0008] A variable frequency compression system, the variable frequency compression system comprising a variable frequency compressor and a second four-way valve, the second four-way valve having a fifth opening, a sixth opening, a seventh opening and an eighth opening, the water outlet of the variable frequency compressor being in communication with the fifth opening, and the water return port of the variable frequency compressor being in communication with the seventh opening;

[0009] a first heat exchanger;

[0010] a second heat exchanger;

[0011] First fan;

[0012] a second fan, the second fan being arranged at an air outlet of the aircraft air conditioner;

[0013] Among them, the first fan is arranged at the first heat exchanger, the second fan is arranged at the second heat exchanger, the first heat exchanger and the second heat exchanger are connected, the second opening and the sixth opening are both connected to the first heat exchanger, and the fourth opening and the eighth opening are both connected to the second heat exchanger.

[0014] By adopting the above scheme, the fixed frequency compression system and the variable frequency compression system are combined to set up, and the frequency of the variable frequency compression system is adjusted to match the actual power output demand, thereby reducing unnecessary energy consumption and improving energy efficiency. In addition, the selection of the variable frequency compression system enables the unit to start without impact and respond to changes in the grid load, realizing demand-side management, which is conducive to reducing damage to mechanical equipment and stabilizing the operation of the grid.

[0015] The first four-way valve is set to switch the refrigerant of the fixed-frequency compressor, and the second four-way valve is set to switch the refrigerant of the variable-frequency compressor. When cooling, the first heat exchanger is used as a condenser, and the second heat exchanger is used as an evaporator. When heating, the first heat exchanger is used as an evaporator, and the second heat exchanger is used as a condenser, thereby replacing the electric heating in the prior art and improving the energy efficiency ratio.

[0016] Furthermore, the fixed-frequency compression system is provided with N groups.

[0017] By adopting the above solution, N groups of fixed-frequency compression systems are set up to meet the needs of larger venues. At the same time, N groups of fixed-frequency compression systems are set up. Even if one group of fixed-frequency compression systems fails, the remaining fixed-frequency compression systems can still perform cooling or heating.

[0018] Furthermore, the variable frequency compression system is provided with M groups.

[0019] By adopting the above scheme and setting up M groups of variable frequency compression systems, the upper and lower limits of the overall variable frequency of the unit can be increased, which can not only reduce unnecessary energy waste, but also ensure the originally required cooling or heating effect by adjusting the frequency of the variable frequency compression system when a fixed frequency compression system fails.

[0020] Furthermore, the fixed-frequency compression system is provided with three groups, and the variable-frequency compression system is provided with one group.

[0021] By adopting the above scheme, three fixed-frequency compression systems and one variable-frequency compression system are used to meet the needs of many aircraft ground air conditioning, and efficient and flexible cooling / heating regulation can be achieved. The fixed-frequency compressor is configured in multiple groups and started in stages according to the cooling load demand, while the variable-frequency compressor accurately matches the actual required cooling and heating output through stepless regulation, thus solving the problems of inaccurate cooling control and high energy consumption of the traditional fixed-frequency system. This design can not only achieve a wide range of load adjustment from 25% to 100% in the cooling season, but also ensure the stability of the supply air temperature. In addition, the hierarchical control technology of the multi-stage refrigeration system combined with the variable frequency system not only improves the accuracy of the air supply control, but also achieves the balance of supply and demand of the cooling and heating loads through reasonable output adjustment, and enhances the reliability of the unit. And it effectively reduces energy consumption and reduces energy waste.

[0022] Furthermore, the number of the second fans is the sum of the number of the fixed-frequency compression systems and the variable-frequency compression systems, and all of the second fans are arranged at the second heat exchanger.

[0023] By adopting the above solution, the aircraft air conditioning heat pump unit sets a second fan at the air outlet that is equal to the total number of the fixed-frequency compression system and the variable-frequency compression system, thereby ensuring that the air volume provided by the second fan can match the heat exchange efficiency at the second heat exchanger, thereby ensuring an accurate match between the airflow and the cooling / heating demand.

[0024] Furthermore, a first gas-liquid separator is provided between the fixed-frequency compressor and the third opening.

[0025] By adopting the above scheme, a first gas-liquid separator is arranged between the fixed-frequency compressor and the third opening, that is, the first gas-liquid separator is arranged at the return water port of the fixed-frequency compressor, which effectively improves the operating efficiency and stability of the aircraft air conditioning heat pump unit. The first gas-liquid separator prevents liquid hammer by separating the liquid refrigerant from the gas-liquid mixture output from the compressor, protects the compressor from damage, and extends the life of the equipment. At the same time, it ensures that only gaseous refrigerant enters the subsequent refrigeration cycle, improves the refrigeration efficiency, accelerates the refrigeration process, enhances the system's adaptability to different working conditions, reduces energy consumption, reduces maintenance costs, and ensures the efficient operation of the evaporator.

[0026] Furthermore, a second gas-liquid separator is provided between the variable frequency compressor and the seventh opening.

[0027] By adopting the above scheme, a first gas-liquid separator is arranged between the variable frequency compressor and the seventh opening, that is, a second gas-liquid separator is arranged at the water return port of the variable frequency compressor, which effectively improves the operating efficiency and stability of the aircraft air conditioning heat pump unit. The second gas-liquid separator prevents liquid hammer by separating the liquid refrigerant from the gas-liquid mixture output from the compressor, protects the compressor from damage, and extends the life of the equipment. At the same time, it ensures that only gaseous refrigerant enters the subsequent refrigeration cycle, improves the refrigeration efficiency, accelerates the refrigeration process, enhances the system's adaptability to different working conditions, reduces energy consumption, reduces maintenance costs, and ensures the efficient operation of the evaporator.

[0028] Furthermore, the variable frequency compressor and / or the fixed frequency compressor is provided with a high pressure sensor.

[0029] By adopting the above solution, the high-pressure state in the refrigeration cycle can be monitored in real time to ensure that the system operates within the safe pressure range, effectively prevent equipment damage caused by abnormal pressure, and extend the life of the compressor. At the same time, it can also optimize the system energy efficiency. Through accurate pressure data feedback, the control system can dynamically adjust the working parameters of the variable frequency compressor or fixed frequency compressor to maximize the utilization of energy efficiency. Especially in the application of variable frequency compressors, stepless adjustment can be achieved to achieve the dual goals of high efficiency energy saving and precise control of ambient temperature.

[0030] Furthermore, the first fan is an axial flow fan.

[0031] By adopting the above solution, the axial flow fan can achieve strong airflow output with low energy consumption, which directly promotes the improvement of the energy efficiency ratio of the entire air conditioning system, thereby reducing operating costs. More importantly, the low noise level of the axial flow fan during operation greatly reduces the noise of the aircraft ground unit. Combined with the inherent air volume adjustability of the axial flow fan, it can accurately match the real-time cooling or heating needs, ensuring the constant and comfortable environment in the working space of the heat pump unit. In addition, the simple maintenance feature makes daily maintenance more convenient, reduces maintenance costs and system downtime, and ensures the stable and reliable operation of the unit.

[0032] Furthermore, a throttling device is provided between the first heat exchanger and the second heat exchanger.

[0033] By adopting the above solution, a throttling device is configured between the first heat exchanger and the second heat exchanger, which can improve the system performance and energy efficiency. The throttling device ensures the efficient evaporation process by accurately controlling the refrigerant flow, thereby greatly improving the energy efficiency ratio while meeting the cooling demand under different working conditions.

[0034] In summary, the heat pump unit of an aircraft air conditioner provided by the utility model has the following technical effects:

[0035] 1. Combining the design of fixed frequency and variable frequency compression system, the heat pump unit can accurately match the power output by adjusting the working frequency of the variable frequency compressor according to the actual cooling or heating needs, avoiding excessive cooling or heating, reducing energy waste, and more importantly, by adjusting the working frequency of the variable frequency compression system to increase and decrease, the heat / cold amount delivered at the air outlet is relatively stable, improving the comfort of the environment it acts on. The dynamic adjustment mechanism significantly improves the energy efficiency ratio and reduces the overall operating cost.

[0036] 2. The introduction of variable frequency compressor enables the unit to start smoothly, avoiding the high current shock at the moment of startup, reducing the wear of the corresponding components and extending the service life of the equipment. At the same time, it can also quickly respond to changes in grid load and adjust its own output according to the demand side management principle, which helps to maintain the stability and efficiency of grid operation.

[0037] 3. The first four-way valve and the second four-way valve are set as the refrigerant flow direction, ensuring that the refrigerant can flow correctly in cooling and heating modes. In cooling mode, the first heat exchanger acts as a condenser and the second heat exchanger acts as an evaporator, effectively releasing cold; in heating mode, the roles of the two are reversed, the first heat exchanger becomes an evaporator, and the second heat exchanger becomes a condenser, achieving efficient conversion of hot and cold modes without relying on electric heating, further improving energy efficiency.

[0038] 4. Under heating conditions, the four-way valve can be switched to convert the evaporator in cooling mode into a condenser, using the heat pump principle instead of electric heating to provide heat, greatly improving the heating efficiency. It not only significantly improves the energy efficiency ratio (usually the energy efficiency ratio is greater than 2), but also greatly reduces the energy consumption of electric heating, saving heating costs for users and reducing carbon emissions to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the refrigerant flow direction in the refrigeration working condition of the utility model;

[0040] Figure 2 It is a schematic diagram of the refrigerant flow direction of the refrigeration working condition of the multiple fixed frequency compression system of the utility model;

[0041] Figure 3 This is a schematic diagram of the refrigerant flow direction in the heating condition of the multiple fixed-frequency compression system of the utility model.

[0042] Among them, the meanings of the figure marks are as follows: 1. fixed frequency compression system; 11. fixed frequency compressor; 12. first four-way valve; 121. first opening; 122. second opening; 123. third opening; 124. fourth opening; 2. variable frequency compression system; 21. variable frequency compressor; 22. second four-way valve; 221. fifth opening; 222. sixth opening; 223. seventh opening; 224. eighth opening; 3. first heat exchanger; 4. second heat exchanger; 5. first fan; 6. second fan; 7. high pressure sensor; 8. throttling device; 9. air outlet. DETAILED DESCRIPTION

[0043] For better understanding and implementation, the technical solutions in the embodiments of the present invention will be clearly and completely described and discussed below in conjunction with the accompanying drawings of the present invention. Obviously, what is described here is only a part of the examples of the present invention, not all the examples. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0044] In order to facilitate the understanding of the embodiments of the present utility model, the following will be further explained by taking specific embodiments as examples in conjunction with the drawings, and each embodiment does not constitute a limitation on the embodiments of the present utility model.

[0045] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0047] See also Figure 1-Figure 3The utility model discloses a heat pump unit of an aircraft air conditioner, comprising: a fixed frequency compression system 1, a variable frequency compression system 2, a first heat exchanger 3, a second heat exchanger 4, a first fan 5 and a second fan 6. The fixed frequency compression system 1 comprises a fixed frequency compressor 11 and a first four-way valve 12. The first four-way valve 12 has a first opening 121, a second opening 122, a third opening 123 and a fourth opening 124. The water outlet of the fixed frequency compressor 11 is communicated with the first opening 121, and the water return port of the fixed frequency compressor 11 is communicated with the third opening 123. The variable frequency compression system 2 comprises a variable frequency compressor 21 and a second four-way valve 22. The second four-way valve 22 has a fifth opening 221, a sixth opening 222, a seventh opening 223 and an eighth opening 224. The water outlet of the variable frequency compressor 21 is communicated with the fifth opening 221, and the water return port of the variable frequency compressor 21 is communicated with the seventh opening 223. The second fan 6 is arranged at the air outlet 9 of the aircraft air conditioner, wherein the first fan 5 is arranged at the first heat exchanger 3, and the second fan 6 is arranged at the second heat exchanger 4, the first heat exchanger 3 is connected to the second heat exchanger 4, the second opening 122 and the sixth opening 222 are both connected to the first heat exchanger 3, and the fourth opening 124 and the eighth opening 224 are both connected to the second heat exchanger 4.

[0048] Specifically, under refrigeration conditions, refer to Figure 2 As shown, the first heat exchanger 3 is used as a condenser, and the second heat exchanger 4 is used as an evaporator. The specific refrigerant flow is as follows:

[0049] The refrigerant of the fixed-frequency compression system 1 flows from the fixed-frequency compressor 11 to the first four-way valve 12. At this time, the first opening 121 of the first four-way valve 12 is connected to the second opening 122, and the third opening 123 is connected to the fourth opening 124. The refrigerant flows in through the first opening 121 and flows out through the second opening 122. After entering the first heat exchanger 3 (i.e., condenser) to condense and release heat, and the first fan 5 is installed at the first heat exchanger 3 (condenser), when the refrigerant condenses and releases heat in the condenser, the first fan 5 accelerates the air flow through the condenser surface, thereby enhancing the heat exchange efficiency in the condensation process. The refrigerant then flows into the second heat exchanger 4 (i.e., evaporator) to evaporate and absorb heat. The second fan 6 is installed at the second heat exchanger 4 (evaporator), and the cold air generated by the heat absorbed by the refrigerant during evaporation is sent into the working environment of the heat pump unit. After that, the refrigerant flows into the first four-way valve 12 through the fourth opening 124, flows out of the first four-way valve 12 through the third opening 123, and finally flows back to the fixed-frequency compressor 11;

[0050] The refrigerant of the variable frequency compression system 2 flows from the variable frequency compressor 21 to the second four-way valve 22. At this time, the fifth opening 221 of the second four-way valve 22 is connected to the sixth opening 222, and the seventh opening 223 is connected to the eighth opening 224. The refrigerant flows in through the fifth opening 221 and flows out through the sixth opening 222. After entering the first heat exchanger 3 (i.e., condenser) to condense and release heat, it flows into the second heat exchanger 4 (i.e., evaporator) to evaporate and absorb heat, flows into the second four-way valve 22 through the eighth opening 224, flows out of the second four-way valve 22 through the seventh opening 223, and finally flows back to the variable frequency compressor 21. The purpose of setting the first fan 5 and the second fan 6 is the same as that in the fixed frequency compression system 1, and will not be repeated here.

[0051] In heating condition, refer to Figure 3 As shown, the first heat exchanger 3 is used as an evaporator, and the second heat exchanger 4 is used as a condenser. The specific refrigerant flow is as follows:

[0052] The refrigerant of the fixed-frequency compression system 1 flows from the fixed-frequency compressor 11 to the first four-way valve 12. At this time, the first opening 121 of the first four-way valve 12 is connected to the fourth opening 124, and the second opening 122 is connected to the third opening 123. After the refrigerant flows into the first four-way valve 12 through the first opening 121, it flows out of the first four-way valve 12 through the fourth opening 124, and then flows into the second heat exchanger 4 (i.e., condenser). The refrigerant condenses and releases heat in the second heat exchanger 4. The hot air affected by the heat release of the refrigerant is sent into the working environment of the heat pump unit through the second fan 6. After condensing and releasing heat, the refrigerant flows into the first heat exchanger 3 (i.e., evaporator), evaporates and absorbs heat in the first heat exchanger 3, and the first fan 5 arranged at the first heat exchanger 3 accelerates the air flow through the surface of the evaporator to help the refrigerant absorb the heat in the air more effectively. The refrigerant then flows back to the fixed-frequency compressor 11 through the second opening 122 and the third opening 123;

[0053] The refrigerant of the variable frequency compression system 2 flows from the variable frequency compressor 21 to the second four-way valve 22. At this time, the fifth opening 221 of the second four-way valve 22 is connected to the eighth opening 224, and the sixth opening 222 is connected to the seventh opening 223. After the refrigerant flows into the second four-way valve 22 through the fifth opening 221, it flows out of the second four-way valve 22 through the eighth opening 224, and then flows into the second heat exchanger 4 (i.e., condenser). The refrigerant condenses and releases heat in the second heat exchanger 4. After condensing and releasing heat, the refrigerant flows into the first heat exchanger 3 (i.e., evaporator), evaporates and absorbs heat in the first heat exchanger 3, and then flows back to the variable frequency compressor 21 after passing through the sixth opening 222 and the seventh opening 223.

[0054] The above configuration is performed by combining the fixed frequency compression system 1 and the variable frequency compression system 2. The frequency of the variable frequency compression system 2 is adjusted to match the actual power output demand, thereby reducing unnecessary energy consumption and improving energy efficiency. In addition, the selection of the variable frequency compression system 2 enables the unit to start without impact and respond to changes in the grid load, thus achieving demand-side management, which is beneficial to reducing damage to mechanical equipment and stabilizing the operation of the grid.

[0055] And by switching the first four-way valve 12 and the second four-way valve 22, the component that originally serves as an evaporator in the cooling mode can be transformed into a condenser, and the heat is provided by the heat pump principle instead of electric heating, which greatly improves the heating efficiency. This method not only significantly improves the energy efficiency ratio (usually the energy efficiency ratio is greater than 2), but also greatly reduces the energy consumption of electric heating, saving heating costs for users and reducing carbon emissions to the environment.

[0056] In some embodiments, in order to improve the overall performance of the heat pump unit, the fixed-frequency compression system 1 is provided with N groups, and a variety of options are provided for different application scenarios. For example, a larger space may use more groups of fixed-frequency compression systems 1, and a smaller space may use fewer groups of fixed-frequency compression systems 1, or even one group of fixed-frequency compression systems 1. At the same time, the fixed-frequency compression system 1 is relatively cheap, and N groups of fixed-frequency compression systems 1 are provided to meet the needs of a larger site. At the same time, N groups of fixed-frequency compression systems 1 are provided, and even if one group of fixed-frequency compression systems 1 fails, the remaining fixed-frequency compression systems 1 can still perform cooling or heating.

[0057] In some embodiments, in order to ensure the adaptability of the heat pump unit, the variable frequency compression system 2 is provided with M groups. By setting up M groups of variable frequency compression systems 2, the upper and lower limits of the overall variable frequency of the unit can be increased, which can not only reduce unnecessary energy waste, but also when a fixed frequency compression system 1 fails, it can adjust the frequency of the variable frequency compression system 2 to ensure the originally required cooling or heating effect. For example, if one group of fixed frequency compression systems 1 or one group of variable frequency compression systems 2 fails, the variable frequency compression system 2 with multiple groups can increase its own operating frequency to ensure that the heating / cooling effect is the same as when there is no failure, so that even if a partial failure occurs in the heat pump unit, the preset heating / cooling task can still be completed, thereby improving the adaptability of the heat pump unit.

[0058] In this embodiment, three groups of fixed frequency compression systems 1 and one group of variable frequency compression systems 2 are provided. By adopting three groups of fixed frequency compression systems 1 and one group of variable frequency compression systems 2, it is possible to meet the needs of many aircraft ground air conditioning, and to achieve efficient and flexible cooling / heating regulation. The fixed frequency compressor 11 is configured in three groups and started in stages according to the cooling load demand, while the variable frequency compressor 21 accurately matches the actual required cooling and heating output through stepless regulation, thereby solving the problems of inaccurate cooling control and high energy consumption of the traditional fixed frequency system. This design can not only achieve a wide range of load adjustment from 25% to 100% in the cooling season, but also ensure the stability of the air supply temperature. In addition, the hierarchical control technology of the multi-stage refrigeration system combined with the variable frequency system not only improves the accuracy of air supply control, but also achieves the balance of supply and demand of cooling and heating loads through reasonable output regulation, thereby enhancing the reliability of the unit. It also effectively reduces energy consumption and reduces energy waste.

[0059] In this embodiment, in order to ensure that the effect at the air outlet of the heat pump unit matches the heating / cooling efficiency of the heat pump unit, the number of second fans 6 is the sum of the number of fixed-frequency compression systems 1 and the variable-frequency compression systems 2, and all second fans 6 are arranged at the second heat exchanger 4. The heat pump unit arranges second fans 6 at the air outlet 9 that are equal to the sum of the number of fixed-frequency compression systems 1 and the variable-frequency compression systems 2, thereby ensuring that the air volume provided by the second fans 6 can match the heat exchange efficiency at the second heat exchanger 4, that is, the processed hot air / cold air can be immediately delivered to the heat pump unit, thereby ensuring the precise match of airflow and cooling / heating requirements.

[0060] In this embodiment, a first gas-liquid separator is provided between the fixed-frequency compressor 11 and the third opening 123. By providing the first gas-liquid separator between the fixed-frequency compressor 11 and the third opening 123, that is, providing the first gas-liquid separator at the water return port of the fixed-frequency compressor 11, the operating efficiency and stability of the aircraft air-conditioning heat pump unit are effectively improved. The first gas-liquid separator prevents liquid hammer by separating the liquid refrigerant from the gas-liquid mixture output from the compressor, protects the compressor from damage, and prolongs the life of the equipment. At the same time, it ensures that only gaseous refrigerant enters the subsequent refrigeration cycle, improves the refrigeration efficiency, accelerates the refrigeration process, enhances the system's adaptability to different working conditions, reduces energy consumption, reduces maintenance costs, and ensures the efficient operation of the evaporator.

[0061] Correspondingly, a second gas-liquid separator is provided between the variable frequency compressor 21 and the seventh opening 223. By providing the first gas-liquid separator between the variable frequency compressor 21 and the seventh opening 223, that is, providing the second gas-liquid separator at the water return port of the variable frequency compressor 21, the operating efficiency and stability of the aircraft air conditioning heat pump unit are effectively improved. The second gas-liquid separator prevents liquid hammer by separating the liquid refrigerant from the gas-liquid mixture output from the compressor, protects the compressor from damage, and prolongs the life of the equipment. At the same time, it ensures that only gaseous refrigerant enters the subsequent refrigeration cycle, improves the refrigeration efficiency, accelerates the refrigeration process, enhances the system's adaptability to different working conditions, reduces energy consumption, reduces maintenance costs, and ensures the efficient operation of the evaporator.

[0062] In this embodiment, the variable frequency compressor 21 and / or the fixed frequency compressor 11 are provided with a high pressure sensor 7, which can monitor the high pressure state in the refrigeration cycle in real time, ensure that the system operates within a safe pressure range, effectively prevent equipment damage caused by abnormal pressure, and extend the life of the compressor. At the same time, it can also optimize the system energy efficiency. Through accurate pressure data feedback, the control system can dynamically adjust the working parameters of the variable frequency compressor 21 or the fixed frequency compressor 11 to maximize the utilization of energy efficiency. In particular, in the application of the variable frequency compressor 21, stepless adjustment can be achieved to achieve the dual goals of high efficiency energy saving and precise control of ambient temperature.

[0063] In this embodiment, the first fan 5 is an axial flow fan, which can achieve powerful airflow output with low energy consumption, directly promoting the improvement of the energy efficiency ratio of the entire air conditioning system, thereby reducing the operating cost. More importantly, the low noise level of the axial flow fan during operation greatly reduces the noise of the aircraft ground unit. Combined with the inherent air volume adjustability of the axial flow fan, it can accurately match the real-time cooling or heating needs, ensuring the constant and comfortable environment in the working space of the heat pump unit. In addition, the simple maintenance feature makes daily maintenance more convenient, reduces maintenance costs and system downtime, and ensures the stable and reliable operation of the unit.

[0064] In this embodiment, a throttling device 8 is provided between the first heat exchanger 3 and the second heat exchanger 4. The throttling device 8 is configured between the first heat exchanger 3 and the second heat exchanger 4 to improve the system performance and energy efficiency. The throttling device 8 ensures the efficient evaporation process by accurately controlling the refrigerant flow rate, thereby greatly improving the energy efficiency ratio while meeting the cooling capacity requirements under different working conditions.

[0065] The technical means disclosed in the solution of the utility model are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical solutions composed of any combination of the above technical features. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the utility model, and these improvements and modifications are also regarded as the protection scope of the utility model.

Claims

1. A heat pump unit for an aircraft air conditioner, characterized in that: include: A fixed-frequency compression system, the fixed-frequency compression system comprising a fixed-frequency compressor and a first four-way valve, the first four-way valve having a first opening, a second opening, a third opening and a fourth opening, a water outlet of the fixed-frequency compressor being connected to the first opening, and a water return port of the fixed-frequency compressor being connected to the third opening; A variable frequency compression system, the variable frequency compression system comprising a variable frequency compressor and a second four-way valve, the second four-way valve having a fifth opening, a sixth opening, a seventh opening and an eighth opening, the water outlet of the variable frequency compressor being in communication with the fifth opening, and the water return port of the variable frequency compressor being in communication with the seventh opening; a first heat exchanger; a second heat exchanger; First fan; a second fan, the second fan being arranged at an air outlet of the aircraft air conditioner; Among them, the first fan is arranged at the first heat exchanger, the second fan is arranged at the second heat exchanger, the first heat exchanger and the second heat exchanger are connected, the second opening and the sixth opening are both connected to the first heat exchanger, and the fourth opening and the eighth opening are both connected to the second heat exchanger.

2. A heat pump unit for an aircraft air conditioner according to claim 1, characterized in that: The fixed-frequency compression system is provided with N groups.

3. The heat pump unit for an aircraft air conditioner according to claim 1, characterized in that: The variable frequency compression system is provided with M groups.

4. The heat pump unit for an aircraft air conditioner according to claim 1, characterized in that: The fixed frequency compression system is provided with three groups, and the variable frequency compression system is provided with one group.

5. A heat pump unit for an aircraft air conditioner according to any one of claims 1 to 4, characterized in that: The number of the second fans is the sum of the number of the fixed-frequency compression systems and the variable-frequency compression systems, and all of the second fans are arranged at the second heat exchanger.

6. The heat pump unit for an aircraft air conditioner according to claim 1, characterized in that: A first gas-liquid separator is provided between the fixed-frequency compressor and the third opening.

7. The heat pump unit for an aircraft air conditioner according to claim 1, characterized in that: A second gas-liquid separator is provided between the variable frequency compressor and the seventh opening.

8. The heat pump unit for an aircraft air conditioner according to claim 1, characterized in that: The variable frequency compressor and / or the fixed frequency compressor is provided with a high pressure sensor.

9. The heat pump unit for an aircraft air conditioner according to claim 1, characterized in that: The first fan is an axial flow fan.

10. The heat pump unit for an aircraft air conditioner according to claim 1, characterized in that: A throttling device is provided between the first heat exchanger and the second heat exchanger.

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