Heat pump air conditioning system

Abstract

The utility model provides a kind of heat pump air conditioning system, including through pipeline connection formation refrigerant circulation loop's compressor unit, four-way valve, first heat exchanger, economizer air supplement structure and second heat exchanger, wherein, compressor unit includes multiple parallelly arranged compressor, and the multiple air supplement pipes of economizer air supplement structure are connected with the air injection port of multiple compressor one-to-one corresponding;The heat pump air conditioning system provided by the utility model is equipped with economizer air supplement structure, and each air supplement pipe of the economizer air supplement structure respectively guides air supplement airflow to the air injection port of each compressor, so that air supplement airflow is mixed with main airflow inside compressor, and then effectively reduces the exhaust temperature of each compressor.

Description

Technical Field

[0001] This utility model belongs to the field of air conditioning, and more specifically, it relates to a heat pump air conditioning system. Background Technology

[0002] The heating market in northern China is experiencing rapid growth in demand, leading to a trend towards ultra-low temperature, high water temperature, variable frequency, and large-scale equipment. However, the current market is still dominated by fixed-frequency heating units, although variable-frequency units are rapidly entering the market. To reduce costs, manufacturers are increasingly using rotary compressors in modular units, employing parallel systems to reduce the number of components and simplify piping design, thereby lowering unit costs and improving cost-effectiveness.

[0003] Low Global Warming Potential (GWP) environmentally friendly refrigerants have become one of the important directions for the future development of air conditioning products. The use of R32 refrigerant in multi-unit parallel systems has been widely adopted. However, R32 refrigerant has the problem of high exhaust temperature, which affects the reliability of the equipment. Utility Model Content

[0004] The purpose of this invention is to provide a heat pump air conditioning system that solves the problem of excessively high exhaust temperature of R32 heat pumps based on multi-unit parallel low-temperature enthalpy enhancement technology, thereby improving the reliability and cost-effectiveness of the product.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: This utility model provides a heat pump air conditioning system, including a compressor unit that forms a refrigerant circulation loop through pipelines, a four-way valve, a first heat exchanger, an economizer gas supply structure, and a second heat exchanger. The compressor unit includes multiple compressors arranged in parallel, and the multiple gas supply pipes of the economizer gas supply structure are connected one-to-one with the gas nozzles of the multiple compressors.

[0006] Furthermore, the economizer gas supply structure includes multiple economizers arranged in parallel. Each economizer has a main pipeline and an auxiliary pipeline for mutual heat exchange. The main pipeline's main inlet is connected to the first heat exchanger and the second heat exchanger via a main inlet pipe. The main pipeline's main outlet is connected to the first heat exchanger and the second heat exchanger via a main throttling outlet pipe. The auxiliary pipeline's auxiliary inlet is connected to the main throttling outlet pipe via an auxiliary throttling inlet pipe. The auxiliary pipeline's auxiliary outlet is connected to the compressor via the gas supply pipe.

[0007] Furthermore, the multiple main throttling outlet pipes connected to the multiple economizers merge to form a main throttling confluence outlet pipe, which is connected between the first heat exchanger and the second heat exchanger, and is equipped with a main throttling valve.

[0008] Furthermore, the auxiliary road throttling inlet pipes, which are connected to the multiple economizers, merge to form an auxiliary road throttling confluence inlet pipe. The auxiliary road throttling confluence inlet pipe is connected to the main road throttling confluence outlet pipe, and the auxiliary road throttling confluence inlet pipe is equipped with an auxiliary road throttling valve.

[0009] Furthermore, the economizer gas supply structure includes a back-to-back economizer. The back-to-back economizer has a main pipeline and multiple auxiliary pipelines that exchange heat with the main pipeline. The main pipeline's main inlet is connected to the first heat exchanger and the second heat exchanger via a main inlet pipe. The main pipeline's main outlet is connected to the first heat exchanger and the second heat exchanger via a main throttling outlet pipe. The multiple auxiliary pipelines are connected to an auxiliary inlet via a distributor. The auxiliary inlet is connected to the main throttling outlet pipe via an auxiliary throttling inlet pipe. The auxiliary outlet of each auxiliary pipeline is connected to the compressor via the gas supply pipe.

[0010] Furthermore, the main throttling outlet pipe is equipped with a main throttling valve, and the auxiliary throttling inlet pipe is equipped with an auxiliary throttling valve.

[0011] Furthermore, the first heat exchanger is connected to the main inlet pipe via a first one-way valve, which only allows refrigerant to flow to the main inlet; the second heat exchanger is connected to the main outlet pipe via a second one-way valve, which only allows refrigerant to flow to the second heat exchanger; the second heat exchanger is connected to the main inlet pipe via a third one-way valve, which only allows refrigerant to flow to the main inlet; and the first heat exchanger is connected to the main outlet pipe via a fourth one-way valve, which only allows refrigerant to flow to the first heat exchanger.

[0012] Furthermore, it also includes a gas-liquid separator, which is disposed between the four-way valve and the compressor unit, and the multiple outlet branches of the gas-liquid separator are connected to the intake ports of the multiple compressors one by one.

[0013] Furthermore, it also includes an oil separator, which is disposed between the four-way valve and the compressor unit. The oil separator is connected to the exhaust side of the compressor unit through an oil inlet pipe assembly, and the oil separator is connected to the intake side of the compressor unit through a return oil throttling pipe assembly.

[0014] Furthermore, the return oil throttling pipe group is configured as two groups, namely a first return oil throttling pipe group and a second return oil throttling pipe group. The operating temperature of the first return oil throttling pipe group is higher than that of the second return oil throttling pipe group. The oil separator is directly connected to the first return oil throttling pipe group, and the oil separator is selectively connected to the second return oil throttling pipe group through a return oil valve.

[0015] Compared with the prior art, the beneficial effects of the heat pump air conditioning system provided by this utility model are as follows: The heat pump air conditioning system provided by this utility model is equipped with an economizer gas injection structure. Each gas injection pipe of the economizer gas injection structure guides the gas injection flow to the jet port of each compressor, so that the gas injection flow mixes with the main air flow inside the compressor, thereby effectively reducing the exhaust temperature of each compressor. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the heat pump air conditioning system in Embodiment 1 of this utility model; Figure 2 This is a schematic diagram of the heat pump air conditioning system in heating mode according to Embodiment 1 of this utility model; Figure 3 This is a schematic diagram of the heat pump air conditioning system in cooling mode according to Embodiment 1 of this utility model; Figure 4 This is a schematic diagram of the heat pump air conditioning system in Embodiment 2 of this utility model; Figure 5 This is a schematic diagram of the heat pump air conditioning system in heating mode according to Embodiment 2 of this utility model; Figure 6 This is a schematic diagram of the heat pump air conditioning system in cooling mode according to Embodiment 2 of this utility model; The main markings in the attached figures are as follows: 1. Compressor unit; 2. Four-way valve; 3. First heat exchanger; 4. Economizer air supply structure; 41. Main line inlet; 42. Main line outlet; 43. Auxiliary line inlet; 44. Auxiliary line outlet; 45. Main line throttle valve; 46. Auxiliary line throttle valve; 5. Second heat exchanger; 61. First check valve; 62. Second check valve; 63. Third check valve; 64. Fourth check valve; 7. Gas-liquid separator; 70. Gas outlet branch pipe; 8. Oil separator; 81. First return oil throttling pipe assembly; 82. Second return oil throttling pipe assembly; 83. Return oil valve. Detailed Implementation

[0018] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0019] The heating market demand in northern China is growing rapidly, and the application of low-temperature heat pump heating is gradually expanding to Northeast China, Inner Mongolia, and Northwest China. Equipment is showing a trend towards ultra-low temperature, high water temperature, variable frequency, and large-scale development. However, the current market is still dominated by fixed-frequency heating units, although variable-frequency heating units are rapidly entering the market. To reduce product costs, manufacturers are increasingly using rotary compressors in modular products, reducing the number of components and simplifying piping design through multi-unit parallel systems, thereby lowering unit costs and improving product cost-effectiveness.

[0020] In accordance with the Kigali Amendment process and my country's "dual carbon" goals, low-GWP environmentally friendly refrigerants have become one of the important directions for the future development of air conditioning products. Gree, leveraging its strong technological R&D capabilities, has conducted in-depth technological innovation and product development in the field of environmentally friendly refrigerants in recent years. Among these, its air-cooled chilled (hot) water products, based on multi-unit parallel systems and using R32 refrigerant, have completed a series of R&D and promotion efforts. However, R32 refrigerant has the problem of high exhaust temperature, affecting the reliability of the equipment.

[0021] Based on this, this utility model proposes a heat pump air conditioning system, which aims to solve the problems of excessively high exhaust temperature and uneven exhaust temperature in the current multi-unit parallel low-temperature enthalpy-increasing R32 heat pump, thereby improving the reliability and cost performance of the product.

[0022] Example 1 like Figure 1 As shown, the heat pump air conditioning system mainly includes a compressor unit 1, a four-way valve 2, a first heat exchanger 3, an economizer gas supply structure 4, and a second heat exchanger 5, which are connected by pipes to form a refrigerant circulation loop. The number of compressors in the compressor unit 1 can be flexibly configured according to actual needs. This embodiment will be described in detail using a dual-compressor configuration as an example.

[0023] The compressor unit 1 comprises two compressors arranged in parallel, and the two injection pipes of the economizer injection structure 4 are connected one-to-one with the injection ports of the two compressors. R32 refrigerant is used in the refrigerant circulation loop. The first heat exchanger 3 is a shell-and-tube heat exchanger, and the second heat exchanger 5 is a finned heat exchanger equipped with a fan.

[0024] In this embodiment, the heat pump air conditioning system is equipped with an economizer gas supply structure 4. Each gas supply pipe of the economizer gas supply structure 4 guides the gas supply airflow to the jet port of each compressor, so that the gas supply airflow mixes with the main airflow inside the compressor, thereby effectively reducing the exhaust temperature of each compressor.

[0025] like Figure 1 As shown, the economizer gas supply structure 4 includes two economizers arranged in parallel. Each economizer has a main pipeline and an auxiliary pipeline for mutual heat exchange. The main pipeline inlet 41 is connected to the first heat exchanger 3 and the second heat exchanger 5 through the main pipeline inlet pipe. The main pipeline outlet 42 is connected to the first heat exchanger 3 and the second heat exchanger 5 through the main pipeline throttling outlet pipe. The auxiliary pipeline inlet 43 is connected to the main pipeline throttling outlet pipe through the auxiliary pipeline throttling inlet pipe. The auxiliary pipeline outlet 44 is connected to the compressor through the gas supply pipe.

[0026] The heat pump air conditioning system operates in two modes: cooling mode and heating mode. When the heat pump air conditioning system is running in cooling or heating mode, one of the first heat exchanger 3 and the second heat exchanger 5 acts as a condenser, while the other acts as an evaporator.

[0027] In this embodiment, the economizer injection structure 4 equips each compressor with an independent economizer. The refrigerant output from the condenser enters each economizer through multiple channels. After throttling and pressure reduction in each economizer, it is guided to the nozzle of each compressor through its respective injection pipe, thereby effectively reducing the exhaust temperature of each compressor. For each economizer, the refrigerant output from the condenser flows sequentially through the main inlet pipe, the main pipeline, and the main throttling outlet pipe. In the main throttling outlet pipe, a portion of the refrigerant flows to the evaporator, while the other portion flows sequentially through the auxiliary throttling inlet pipe, the auxiliary pipeline, and the injection pipe. At the same time, the refrigerant in the auxiliary pipeline exchanges heat with the refrigerant in the main pipeline, allowing the refrigerant flowing to the evaporator to be cooled in the main pipeline, thereby reducing the enthalpy of the refrigerant entering the evaporator and improving heat exchange efficiency.

[0028] In addition, by equipping each compressor with an independent economizer, the uneven exhaust temperature of multiple compressors operating at the same frequency can be effectively alleviated to some extent from a structural design perspective.

[0029] like Figure 1 As shown, the two main throttling outlet pipes connected to the two economizers merge to form a main throttling confluence outlet pipe. This main throttling confluence outlet pipe connects the first heat exchanger 3 and the second heat exchanger 5, and is equipped with a main throttling valve 45. This design effectively reduces the number of valves, thereby lowering costs. Of course, in other optional implementation schemes, to achieve better control performance, independent main throttling valves 45 can be installed on the main throttling outlet pipes of each economizer to improve overall performance.

[0030] like Figure 1As shown, the two auxiliary throttling inlets connected to the two economizers merge to form an auxiliary throttling confluence inlet, which is connected to the main throttling confluence outlet. The auxiliary throttling confluence inlet is equipped with an auxiliary throttling valve 46. This design effectively reduces the number of valves, thereby lowering costs. Of course, in other alternative implementations, to achieve better control, independent auxiliary throttling valves 46 can be installed on each auxiliary throttling inlet of the economizer. In this case, from a method control perspective, the discharge temperature of each compressor can be more precisely adjusted by regulating the opening of each auxiliary throttling valve 46, thereby effectively avoiding uneven discharge temperatures of multiple compressors caused by structural assembly errors or other unforeseen factors.

[0031] like Figure 1 As shown, the first heat exchanger 3 is connected to the main inlet pipe via a first one-way valve 61, which only allows refrigerant to flow to the main inlet 41. The second heat exchanger 5 is connected to the main throttling outlet pipe via a second one-way valve 62, which only allows refrigerant to flow to the second heat exchanger 5. The second heat exchanger 5 is connected to the main inlet pipe via a third one-way valve 63, which only allows refrigerant to flow to the main inlet 41. The first heat exchanger 3 is connected to the main throttling outlet pipe via a fourth one-way valve 64, which only allows refrigerant to flow to the first heat exchanger 3. This design utilizes the unidirectional flow characteristic of the one-way valves to ensure that the refrigerant can only flow from the first heat exchanger 3 (which acts as a condenser) or the second heat exchanger 5 to the economizer, preventing reverse flow of refrigerant during system switching between different operating modes, thereby avoiding system pressure disturbances or efficiency reduction. This design requires no additional electrical control signals, simplifying the complexity of valve adjustment.

[0032] like Figure 1 As shown, the heat pump air conditioning system also includes a gas-liquid separator 7, which is located between the four-way valve 2 and the compressor unit 1. The two outlet branches 70 of the gas-liquid separator 7 are connected to the suction ports of the two compressors one-to-one. This design allows each compressor to independently draw air, and combined with the economizer supplementary air structure 4, from a structural design perspective, it effectively alleviates the phenomenon of uneven exhaust temperature of multiple compressors to a certain extent.

[0033] like Figure 1 As shown, the heat pump air conditioning system also includes an oil separator 8, which is located between the four-way valve 2 and the compressor unit 1. The oil separator 8 is connected to the exhaust side of the compressor unit 1 via an oil inlet pipe assembly, and to the suction side of the compressor unit 1 via a return oil throttling pipe assembly. This design efficiently captures lubricating oil in the exhaust gas through the oil separator 8, reducing the likelihood of it entering the refrigerant circulation loop, thereby effectively improving the problem of cylinder seizure caused by insufficient oil in each compressor. Simultaneously, it ensures that each compressor can return oil independently, effectively avoiding the problem of uneven oil return from multiple compressors.

[0034] In addition, each inlet pipe in the oil inlet pipe group is equipped with a one-way valve. The return oil throttling pipe group is configured in two sets: a first return oil throttling pipe group 81 and a second return oil throttling pipe group 82. The operating temperature of the first return oil throttling pipe group 81 is higher than that of the second return oil throttling pipe group 82. The oil separator 8 is directly connected to the first return oil throttling pipe group 81, and selectively connected to the second return oil throttling pipe group 82 through a return oil valve 83. The first return oil throttling pipe group 81 consists of two first return oil throttling pipe groups 81, which are connected one-to-one to the two outlet branches 70 of the gas-liquid separator 7. Each first return oil throttling pipe is equipped with a capillary tube. Similarly, the second return oil throttling pipe group 82 consists of two second return oil throttling pipe groups 82, which are connected one-to-one to the two outlet branches 70 of the gas-liquid separator 7. Each second return oil throttling pipe is equipped with a capillary tube. This design incorporates two sets of oil return throttling pipes for the oil separator 8. The first set remains open, continuously supplying lubricating oil from the oil separator 8 to the compressor, ensuring oil return regardless of operating conditions. The second set activates only under specific conditions, primarily to increase oil return volume when oil return is difficult, preventing compressor damage due to oil shortage. This design ensures the compressor receives sufficient lubricating oil under various operating conditions. Especially under low oil temperature or poor oil quality conditions, the activation of the second set of oil return throttling pipes effectively improves oil return performance.

[0035] For ease of understanding, the working mode of the heat pump air conditioning system in this embodiment will be described in detail below with reference to the accompanying drawings.

[0036] like Figure 2 As shown, when the heat pump air conditioning system is operating in cooling mode, the first heat exchanger 3 acts as the condenser, and the second heat exchanger 5 acts as the evaporator. The refrigerant circulation loop flows as follows: compressor unit 1 → oil separator 8 → four-way valve 2 → first heat exchanger 3 → first one-way valve 61 → economizer gas supply structure 4 (dual economizer) → second one-way valve 62 → second heat exchanger 5 → four-way valve 2 → gas-liquid separator 7 → compressor unit 1.

[0037] like Figure 3 As shown, when the heat pump air conditioning system is operating in cooling mode, the first heat exchanger 3 acts as the evaporator, and the second heat exchanger 5 acts as the condenser. The refrigerant circulation loop flows as follows: compressor unit 1 → oil separator 8 → four-way valve 2 → second heat exchanger 5 → third one-way valve 63 → economizer gas supply structure 4 (dual economizer) → fourth one-way valve 64 → first heat exchanger 3 → four-way valve 2 → gas-liquid separator 7 → compressor unit 1.

[0038] Example 2 like Figure 4As shown, the heat pump air conditioning system mainly includes a compressor unit 1, a four-way valve 2, a first heat exchanger 3, an economizer gas supply structure 4, and a second heat exchanger 5, which are connected by pipes to form a refrigerant circulation loop. The number of compressors in the compressor unit 1 can be flexibly configured according to actual needs. This embodiment will be described in detail using a dual-compressor configuration as an example.

[0039] The compressor unit 1 comprises two compressors arranged in parallel, and the two gas injection pipes of the economizer injection structure 4 are connected one-to-one with the injection ports of the two compressors. R32 refrigerant is used in the refrigerant circulation loop.

[0040] In this embodiment, the heat pump air conditioning system is equipped with an economizer gas supply structure 4. Each gas supply pipe of the economizer gas supply structure 4 guides the gas supply airflow to the jet port of each compressor, so that the gas supply airflow mixes with the main airflow inside the compressor, thereby effectively reducing the exhaust temperature of each compressor.

[0041] like Figure 4 As shown, the economizer gas supply structure 4 includes a back-to-back economizer. The back-to-back economizer has a main pipeline and two auxiliary pipelines that exchange heat with the main pipeline. The main pipeline inlet 41 is connected to the first heat exchanger 3 and the second heat exchanger 5 through the main pipeline inlet pipe. The main pipeline outlet 42 is connected to the first heat exchanger 3 and the second heat exchanger 5 through the main pipeline throttling outlet pipe. The two auxiliary pipelines are connected to an auxiliary pipeline inlet 43 through a distributor. The auxiliary pipeline inlet 43 is connected to the main pipeline throttling outlet pipe through the auxiliary pipeline throttling inlet pipe. The auxiliary pipeline outlet 44 of each auxiliary pipeline is connected to the compressor through a gas supply pipe.

[0042] The heat pump air conditioning system operates in two modes: cooling mode and heating mode. When the heat pump air conditioning system is running in cooling or heating mode, one of the first heat exchanger 3 and the second heat exchanger 5 acts as a condenser, while the other acts as an evaporator.

[0043] In this embodiment, the economizer injection structure 4 employs a back-to-back economizer configured for multiple compressors. The refrigerant output from the condenser enters the back-to-back economizer, where it undergoes throttling and pressure reduction before being guided to the nozzles of each compressor through different injection pipes, effectively reducing the exhaust temperature of each compressor. For the back-to-back economizer, the refrigerant output from the condenser flows sequentially through the main inlet pipe, main pipeline, and main throttling outlet pipe. In the main throttling outlet pipe, a portion of the refrigerant flows to the evaporator, while the other portion flows sequentially through the auxiliary throttling inlet pipe, auxiliary pipeline, and injection pipe. Simultaneously, the refrigerant in the auxiliary pipeline exchanges heat with the refrigerant in the main pipeline, allowing the refrigerant flowing to the evaporator to be cooled in the main pipeline, thereby reducing the enthalpy of the refrigerant entering the evaporator and improving heat exchange efficiency.

[0044] It is also worth noting that the back-to-back economizer contains multiple auxiliary pipes. The aforementioned distributor adopts a showerhead-like structural design, which evenly distributes the auxiliary fluid to each auxiliary pipe, ensuring that each auxiliary pipe receives the same flow rate. Without a distributor, the auxiliary fluid might receive more in the near-end air supply pipe and less in the far-end air supply pipe, resulting in inconsistent air supply to multiple compressors and affecting the uniformity of their exhaust temperatures. By adding a distributor, the flow rate in each auxiliary pipe can be kept consistent, allowing the auxiliary fluid to be more evenly distributed to multiple air supply pipes, thus effectively alleviating the problem of uneven exhaust temperatures among multiple compressors. This economizer air supply structure 4 improves the uniformity of exhaust temperatures among multiple compressors through optimized distribution structure design.

[0045] like Figure 4 As shown, the main throttling outlet pipe is equipped with a main throttling valve 45, and the auxiliary throttling inlet pipe is equipped with an auxiliary throttling valve 46. This design effectively reduces the number of valves, thereby lowering costs. Of course, in other alternative implementation schemes, to achieve better control, independent main throttling valves 45 can be installed on the main throttling outlet pipes of each economizer, or independent auxiliary throttling valves 46 can be installed on the auxiliary throttling inlet pipes of each economizer. In this case, from a method control perspective, the discharge temperature of each compressor can be more precisely adjusted by regulating the opening of each auxiliary throttling valve 46, thereby effectively avoiding uneven discharge temperatures of multiple compressors caused by structural assembly errors or other unforeseen factors.

[0046] like Figure 4 As shown, the first heat exchanger 3 is connected to the main inlet pipe via a first one-way valve 61, which only allows refrigerant to flow to the main inlet 41. The second heat exchanger 5 is connected to the main throttling outlet pipe via a second one-way valve 62, which only allows refrigerant to flow to the second heat exchanger 5. The second heat exchanger 5 is connected to the main inlet pipe via a third one-way valve 63, which only allows refrigerant to flow to the main inlet 41. The first heat exchanger 3 is connected to the main throttling outlet pipe via a fourth one-way valve 64, which only allows refrigerant to flow to the first heat exchanger 3. This design utilizes the unidirectional flow characteristic of the one-way valves to ensure that the refrigerant can only flow from the first heat exchanger 3 (which acts as a condenser) or the second heat exchanger 5 to the economizer, preventing reverse flow of refrigerant during system switching between different operating modes, thereby avoiding system pressure disturbances or efficiency reduction. This design requires no additional electrical control signals, simplifying the complexity of valve adjustment.

[0047] like Figure 4As shown, the heat pump air conditioning system also includes a gas-liquid separator 7, which is located between the four-way valve 2 and the compressor unit 1. The two outlet branches 70 of the gas-liquid separator 7 are connected to the suction ports of the two compressors one-to-one. This design allows each compressor to independently draw air, and combined with the economizer supplementary air structure 4, from a structural design perspective, it effectively alleviates the phenomenon of uneven exhaust temperature of multiple compressors to a certain extent.

[0048] like Figure 4 As shown, the heat pump air conditioning system also includes an oil separator 8, which is located between the four-way valve 2 and the compressor unit 1. The oil separator 8 is connected to the exhaust side of the compressor unit 1 via an oil inlet pipe assembly, and to the suction side of the compressor unit 1 via an oil return throttling pipe assembly. This design efficiently captures refrigerant oil in the exhaust gas through the oil separator 8, preventing lubricating oil from entering the refrigerant circulation system and thus avoiding cylinder seizure due to insufficient oil in the compressors. Simultaneously, it ensures that each compressor can independently return oil, effectively avoiding the problem of uneven oil return from multiple compressors.

[0049] Furthermore, the return oil throttling pipe group is configured with two sets: a first return oil throttling pipe group 81 and a second return oil throttling pipe group 82. The operating temperature of the first return oil throttling pipe group 81 is higher than that of the second return oil throttling pipe group 82. The oil separator 8 is directly connected to the first return oil throttling pipe group 81, and selectively connected to the second return oil throttling pipe group 82 through a return oil valve 83. The first return oil throttling pipe group 81 consists of two first return oil throttling pipe groups 81, which are connected one-to-one with the two outlet branches 70 of the gas-liquid separator 7. Each first return oil throttling pipe is equipped with a capillary tube. Similarly, the second return oil throttling pipe group 82 consists of two second return oil throttling pipe groups 82, which are connected one-to-one with the two outlet branches 70 of the gas-liquid separator 7. Each second return oil throttling pipe is equipped with a capillary tube. This design provides two sets of return oil throttling pipe groups for the oil separator 8. The first set of oil return throttling pipes remains open, continuously supplying lubricating oil from the oil separator 8 to the compressor, ensuring oil return regardless of operating conditions. The second set of oil return throttling pipes, however, activates only under specific conditions, primarily to increase oil return volume when oil return is difficult, preventing compressor damage due to oil shortage. This design ensures the compressor receives sufficient lubricating oil under various operating conditions. Especially when oil temperature is low or oil quality is poor, activating the second set of oil return throttling pipes effectively improves oil return performance.

[0050] For ease of understanding, the working mode of the heat pump air conditioning system in this embodiment will be described in detail below with reference to the accompanying drawings.

[0051] like Figure 5As shown, when the heat pump air conditioning system is operating in cooling mode, the first heat exchanger 3 acts as the condenser, and the second heat exchanger 5 acts as the evaporator. The refrigerant circulation loop flows as follows: compressor unit 1 → oil separator 8 → four-way valve 2 → first heat exchanger 3 → first one-way valve 61 → economizer gas supply structure 4 (back-to-back economizer) → second one-way valve 62 → second heat exchanger 5 → four-way valve 2 → gas-liquid separator 7 → compressor unit 1.

[0052] like Figure 6 As shown, when the heat pump air conditioning system is operating in cooling mode, the first heat exchanger 3 acts as the evaporator, and the second heat exchanger 5 acts as the condenser. The refrigerant circulation loop flows as follows: compressor unit 1 → oil separator 8 → four-way valve 2 → second heat exchanger 5 → third one-way valve 63 → economizer gas supply structure 4 (back-to-back economizer) → fourth one-way valve 64 → first heat exchanger 3 → four-way valve 2 → gas-liquid separator 7 → compressor unit 1.

[0053] It should be noted that the terminology used above is for describing specific embodiments only and is not intended to limit the exemplary embodiments according to this utility model. When the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. The order of execution of actions, steps, etc., in the apparatus and methods shown in the specification and drawings can be implemented in any order unless a specific express order is specified, and as long as the output of the preceding process is not used in the subsequent process. Similar sequential terms used for ease of description do not imply that such an order must be followed.

[0054] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0055] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A heat pump air conditioning system, characterized in that, The system includes a compressor unit that forms a refrigerant circulation loop through pipelines, a four-way valve, a first heat exchanger, an economizer gas supply structure, and a second heat exchanger. The compressor unit comprises multiple compressors arranged in parallel, and the multiple gas supply pipes of the economizer gas supply structure are connected one-to-one with the jet ports of the multiple compressors.

2. The heat pump air conditioning system as described in claim 1, characterized in that, The economizer gas supply structure includes multiple economizers arranged in parallel. Each economizer has a main pipeline and an auxiliary pipeline for mutual heat exchange. The main pipeline's main inlet is connected to the first heat exchanger and the second heat exchanger via a main inlet pipe. The main pipeline's main outlet is connected to the first heat exchanger and the second heat exchanger via a main throttling outlet pipe. The auxiliary pipeline's auxiliary inlet is connected to the main throttling outlet pipe via an auxiliary throttling inlet pipe. The auxiliary pipeline's auxiliary outlet is connected to the compressor via the gas supply pipe.

3. The heat pump air conditioning system as described in claim 2, characterized in that, Multiple main throttling outlet pipes connected to multiple economizers merge to form a main throttling confluence outlet pipe, which is connected between the first heat exchanger and the second heat exchanger, and is equipped with a main throttling valve.

4. The heat pump air conditioning system as described in claim 3, characterized in that, Multiple auxiliary road throttling inlets connected to multiple economizers merge to form an auxiliary road throttling confluence inlet. The auxiliary road throttling confluence inlet is connected to the main road throttling confluence outlet and is equipped with an auxiliary road throttling valve.

5. The heat pump air conditioning system as described in claim 1, characterized in that, The economizer gas supply structure includes a back-to-back economizer. The back-to-back economizer has a main pipeline and multiple auxiliary pipelines that exchange heat with the main pipeline. The main pipeline's main inlet is connected to the first heat exchanger and the second heat exchanger via a main inlet pipe. The main pipeline's main outlet is connected to the first heat exchanger and the second heat exchanger via a main throttling outlet pipe. The multiple auxiliary pipelines are connected to an auxiliary inlet via a distributor. The auxiliary inlet is connected to the main throttling outlet pipe via an auxiliary throttling inlet pipe. The auxiliary outlet of each auxiliary pipeline is connected to the compressor via the gas supply pipe.

6. The heat pump air conditioning system as described in claim 5, characterized in that, The main throttling outlet pipe is equipped with a main throttling valve, and the auxiliary throttling inlet pipe is equipped with an auxiliary throttling valve.

7. The heat pump air conditioning system as described in claim 2 or 5, characterized in that, The first heat exchanger is connected to the main inlet pipe via a first check valve, which only allows refrigerant to flow to the main inlet; the second heat exchanger is connected to the main outlet pipe via a second check valve, which only allows refrigerant to flow to the second heat exchanger; the second heat exchanger is connected to the main inlet pipe via a third check valve, which only allows refrigerant to flow to the main inlet; and the first heat exchanger is connected to the main outlet pipe via a fourth check valve, which only allows refrigerant to flow to the first heat exchanger.

8. The heat pump air conditioning system as described in claim 1, characterized in that, It also includes a gas-liquid separator, which is disposed between the four-way valve and the compressor unit, and the multiple outlet branches of the gas-liquid separator are connected to the intake ports of the multiple compressors one by one.

9. The heat pump air conditioning system as described in claim 1, characterized in that, It also includes an oil separator, which is disposed between the four-way valve and the compressor unit. The oil separator is connected to the exhaust side of the compressor unit through an oil inlet pipe assembly and to the intake side of the compressor unit through a return oil throttling pipe assembly.

10. The heat pump air conditioning system as described in claim 9, characterized in that, The return oil throttling pipe group is configured into two groups, namely the first return oil throttling pipe group and the second return oil throttling pipe group. The operating temperature of the first return oil throttling pipe group is higher than that of the second return oil throttling pipe group. The oil separator is directly connected to the first return oil throttling pipe group, and the oil separator is selectively connected to the second return oil throttling pipe group through the return oil valve.

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