阅读说明：本技术 一种制冷系统及控制方法 (Refrigerating system and control method ) 是由 吕如兵 梁祥飞 张健伟 郑波 黄健贵 丁凯 于 2021-07-06 设计创作，主要内容包括：本发明提出了一种制冷系统和制冷系统的控制方法,制冷系统包括冷媒循环回路和水循环回路；水循环回路与冷媒循环回路中的第一中间换热器和第二中间换热器分别耦合；在不同运行模式下,第一中间换热器通过水循环回路与每个室内换热组件中的一个室内换热器进行热交换,第二中间换热器通过水循环回路与每个室内换热组件中的另一个室内换热器进行热交换；或者,第一中间换热器通过水循环回路与一部分室外换热组件中的所有室内换热器同时进行热交换；第二中间换热器通过水循环回路与另一部分室外换热组件中的所有室内换热器同时进行热交换。本发明的制冷系统解决了常规水多联系统存在二次换热且供水温度较低导致系统能效低的问题。(The invention provides a refrigeration system and a control method of the refrigeration system, wherein the refrigeration system comprises a refrigerant circulation loop and a water circulation loop; the water circulation loop is respectively coupled with a first intermediate heat exchanger and a second intermediate heat exchanger in the refrigerant circulation loop; under different operation modes, the first intermediate heat exchanger exchanges heat with one indoor heat exchanger in each indoor heat exchange assembly through the water circulation loop, and the second intermediate heat exchanger exchanges heat with the other indoor heat exchanger in each indoor heat exchange assembly through the water circulation loop; or the first intermediate heat exchanger exchanges heat with all indoor heat exchangers in a part of outdoor heat exchange assemblies simultaneously through the water circulation loop; and the second intermediate heat exchanger exchanges heat with all indoor heat exchangers in the other part of outdoor heat exchange assemblies simultaneously through the water circulation loop. The refrigeration system solves the problem that the conventional water multi-connected system has low energy efficiency due to secondary heat exchange and low water supply temperature.)

1. A refrigerating system is characterized by comprising a refrigerant circulation loop and a water circulation loop;

the refrigerant circulating loop comprises a first compression cylinder, a second compression cylinder and a third compression cylinder; the exhaust port of the first compression cylinder, the exhaust port of the second compression cylinder and the exhaust port of the third compression cylinder are connected through a first connecting pipe, the first connecting pipe is connected with a first interface of a four-way valve, the air suction port of the first compression cylinder and the air suction port of the second compression cylinder are respectively connected through a second connecting pipe, and the second connecting pipe is connected with a second interface of the four-way valve; a third interface of the four-way valve is connected with a first end of an outdoor heat exchanger, a second end of the outdoor heat exchanger is connected with a first end of a flash evaporator, a second end of the flash evaporator is connected with a first end of a first intermediate heat exchanger, and a second end of the first intermediate heat exchanger is connected with the second connecting pipe; the third end of the flash evaporator is connected with the first end of a second intermediate heat exchanger, and the second end of the second intermediate heat exchanger is connected with the fourth end of the four-way valve; the fourth end of the flash evaporator is connected with the air suction port of the third compression cylinder; a first control valve is arranged on a pipeline between the second end of the first intermediate heat exchanger and the second connecting pipe, and a second control valve is arranged on the second connecting pipe between the air suction port of the first compression cylinder and the air suction port of the second compression cylinder;

the refrigerant circulation loop further comprises a third connecting pipe, a first end of the third connecting pipe is connected with the first connecting pipe, and a second end of the third connecting pipe is arranged on a pipeline between the first control valve and the first intermediate heat exchanger; a third control valve is arranged on the third connecting pipe;

the water circulation loop is coupled with the first intermediate heat exchanger and the second intermediate heat exchanger respectively; the water circulation loop comprises a plurality of indoor heat exchange assemblies which are respectively arranged in a plurality of indoor spaces, each indoor heat exchange assembly comprises a first indoor heat exchanger and a second indoor heat exchanger which are sequentially arranged along the air circulation direction, the first indoor heat exchanger is positioned on the leeward side, and the second indoor heat exchanger is positioned on the windward side;

in different operation modes, the first intermediate heat exchanger exchanges heat with one indoor heat exchanger in each indoor heat exchange assembly through the water circulation loop, and the second intermediate heat exchanger exchanges heat with the other indoor heat exchanger in each indoor heat exchange assembly through the water circulation loop;

or the first intermediate heat exchanger exchanges heat with all indoor heat exchangers in a part of outdoor heat exchange assemblies simultaneously through the water circulation loop; and the second intermediate heat exchanger exchanges heat with all indoor heat exchangers in the other part of outdoor heat exchange assemblies simultaneously through the water circulation loop.

2. The refrigeration system of claim 1, wherein the water circulation loop comprises a first circulation outlet pipe, a first circulation return pipe, a second circulation outlet pipe and a second circulation return pipe; the first circulating water outlet pipe and the first circulating water return pipe form a first main loop, and the first main loop is coupled with the first intermediate heat exchanger; the second circulating water outlet pipe and the second circulating water return pipe form a second main loop, and the second main loop is coupled with the second intermediate heat exchanger;

a plurality of first branch water paths are arranged between the first circulating water outlet pipe and the second circulating water outlet pipe, and a plurality of second branch water paths are arranged between the first circulating water return pipe and the second circulating water return pipe;

the first ends of all indoor heat exchangers in each heat exchange assembly are respectively connected with a first branch water channel, and the second ends of all indoor heat exchangers in each heat exchange assembly are respectively connected with a second branch water channel;

and three-way valves are respectively arranged between the first branch water path and the first ends of all indoor heat exchangers of each indoor heat exchange assembly and between the second branch water path and the second ends of all indoor heat exchangers in each indoor heat exchange assembly.

3. A refrigeration system as recited in claim 2 wherein a first circulation pump is provided on said first primary loop and a second circulation pump is provided on said second primary loop.

4. A refrigeration system as claimed in claim 2 or 3, wherein said refrigerant circuit comprises three separate compressors, each compressor having a respective compression cylinder.

5. A refrigeration system as recited in claim 2 or 3 wherein said refrigerant circuit includes a compressor, said compressor is a three-cylinder three-suction single-row compressor, three cylinders of said compressor are relatively independent and have independent suction ports, the exhaust from the three cylinders are merged in the interior of said compressor and then discharged out of said compressor through the exhaust port of said compressor, and the exhaust port of said compressor is connected to the first port of said four-way valve.

6. A refrigeration system according to claim 2 or 3, wherein the displacement of said first compression cylinder is Va and the displacement of said second compression cylinder is Vb, such that: the value range of Va/Va is 0.5-2.

7. A refrigeration system as set forth in claim 6 wherein said third compression cylinder has a displacement of Vc: the value range of Vc/(Va + Vb) is 0.05-0.3.

8. A refrigeration system as recited in claim 2 or 3 wherein said first intermediate heat exchanger has a heat transfer area proportional to the displacement of said first compression cylinder and said second intermediate heat exchanger has a heat transfer area proportional to the displacement of said second compression cylinder.

9. A refrigeration system according to claim 8, wherein a first throttling means is provided between the second end of the outdoor heat exchanger and the first end of the flash evaporator, and a second throttling means is provided between the second end of the flash evaporator and the first end of the first intermediate heat exchanger; and a third throttling device is arranged between the third end of the flash evaporator and the second intermediate heat exchanger.

10. The refrigeration system of claim 9, wherein the outdoor heat exchanger is an air-cooled heat exchanger or a water-cooled heat exchanger;

and/or the first intermediate heat exchanger and the second intermediate heat exchanger are in the form of plate heat exchangers, double-pipe heat exchangers or high-efficiency tank heat exchangers and the like;

and/or the first indoor heat exchanger and the second indoor heat exchanger are surface air coolers.

11. A refrigeration system as recited in claim 1 wherein said refrigerant used in said refrigerant circulation circuit is selected from the group consisting of non-flammable refrigerants, flammable low GWP refrigerants, and mixtures thereof.

12. A control method using the refrigerant system as set forth in claim 1,

under different operation modes, the first intermediate heat exchanger is controlled to exchange heat with one indoor heat exchanger in each indoor heat exchange assembly through the water circulation loop, and the second intermediate heat exchanger exchanges heat with the other indoor heat exchanger in each indoor heat exchange assembly through the water circulation loop;

or the first intermediate heat exchanger is controlled to simultaneously exchange heat with all indoor heat exchangers in a part of outdoor heat exchange assemblies through the water circulation loop; and the second intermediate heat exchanger exchanges heat with all indoor heat exchangers in the other part of outdoor heat exchange assemblies simultaneously through the water circulation loop.

13. A control method using the refrigeration system according to any one of claims 2 to 11,

controlling the connection state of the four-way valve and the communication state of three-way valves positioned on a plurality of first branch water paths and a plurality of second branch water paths by controlling the opening and closing conditions of the first control valve, the second control valve and the third control valve, so that the first intermediate heat exchanger exchanges heat with one indoor heat exchanger in each indoor heat exchange assembly through a first main loop, and the second intermediate heat exchanger exchanges heat with the other indoor heat exchanger in each indoor heat exchange assembly through a second main loop;

or the first intermediate heat exchanger exchanges heat with all indoor heat exchangers in a part of the outdoor heat exchange assemblies through a first main loop at the same time; and the second intermediate heat exchanger exchanges heat with all indoor heat exchangers in the other part of the outdoor heat exchange assembly through a second main loop at the same time.

14. The control method of a refrigeration system as recited in claim 13, wherein in the refrigeration mode, the four-way valve is controlled to be in a first conduction state, the first control valve is controlled to be opened, and the second control valve and the third control valve are controlled to be closed;

and controlling the first circulating water outlet pipe to be communicated with the first ends of all the first indoor heat exchangers, controlling the first circulating water return pipe to be communicated with the second ends of all the first indoor heat exchangers, controlling the second circulating water outlet pipe to be communicated with the first ends of all the second indoor heat exchangers, and controlling the second circulating water return pipe to be communicated with the second ends of all the second indoor heat exchangers, so that the first intermediate heat exchanger exchanges heat with all the first indoor heat exchangers through the first main loop, and the second intermediate heat exchanger exchanges heat with all the second indoor heat exchangers through the second main loop.

15. The control method of a refrigeration system as recited in claim 13, wherein in the heating mode, the four-way valve is controlled to be in the second conduction state, the first control valve is controlled to be closed, and the second control valve and the third control valve are controlled to be opened;

and controlling the first circulating water outlet pipe to be communicated with the first ends of all the second indoor heat exchangers, controlling the first circulating water return pipe to be communicated with the second ends of all the second indoor heat exchangers, controlling the second circulating water outlet pipe to be communicated with the first ends of all the first indoor heat exchangers, controlling the second circulating water return pipe to be communicated with the second ends of all the first indoor heat exchangers, so that the first intermediate heat exchangers exchange heat with all the second indoor heat exchangers through the first main loop, and the second intermediate heat exchangers exchange heat with all the first indoor heat exchangers through the second main loop.

16. The control method of a refrigeration system as recited in claim 13, wherein in the dehumidification mode, the four-way valve is controlled to be in a first conduction state, the first control valve is controlled to be closed, and the second control valve and the third control valve are controlled to be opened;

and controlling the first circulating water outlet pipe to be communicated with the first ends of all the first indoor heat exchangers, controlling the first circulating water return pipe to be communicated with the second ends of all the first indoor heat exchangers, controlling the second circulating water outlet pipe to be communicated with the first ends of all the second indoor heat exchangers, and controlling the second circulating water return pipe to be communicated with the second ends of all the second indoor heat exchangers, so that the first intermediate heat exchangers exchange heat with all the first indoor heat exchangers through the first main loop, and the second intermediate heat exchangers exchange heat with all the second indoor heat exchangers through the second main loop.

17. The control method of a refrigeration system as recited in claim 13, wherein in the heat recovery mode, the four-way valve is controlled to be in a first conduction state, the first control valve is controlled to be closed, and the second control valve and the third control valve are controlled to be opened;

the first circulating water outlet pipe is controlled to be communicated with first ends of all indoor heat exchangers in a part of outdoor heat exchange assemblies, and the first circulating water return pipe is controlled to be communicated with second ends of all indoor heat exchangers in the part of outdoor heat exchange assemblies; and controlling the second circulating water outlet pipe to be communicated with the first ends of all the indoor heat exchangers in the other part of the outdoor heat exchange assembly, and controlling the second circulating water return pipe to be communicated with the second ends of all the indoor heat exchangers in the part of the indoor heat exchange assembly, so that the first intermediate heat exchanger can exchange heat with all the indoor heat exchangers in the part of the outdoor heat exchange assembly at the same time through the first main loop, and the second intermediate heat exchanger can exchange heat with all the indoor heat exchangers in the other part of the outdoor heat exchange assembly at the same time through the second main loop.

Technical Field

The invention belongs to the field of refrigeration systems, and particularly relates to a refrigeration system and a control method.

Background

The tail end of a conventional multi-split air conditioning system generally has two forms according to different heat exchange media: the refrigerant system and the water system respectively have different technical characteristics, wherein the refrigerant system has no intermediate heat exchange, so that the energy loss caused by secondary heat exchange is reduced, and the energy efficiency of the whole system is relatively high; and the water system adopted at the tail end can reduce the filling amount of the whole machine refrigerant, and can meet the popularization and application of some refrigerants with low GWP, high energy efficiency and flammability (such as R32, R152a and the like, and mixtures of the refrigerants and other refrigerants) at the same time, but the energy efficiency of the system is reduced due to the fact that secondary heat exchange exists when the tail end of the refrigerant in the multi-connected air room is simply replaced by the tail end of water, and meanwhile, the initial investment of loading a refrigerant heat exchanger and a water pump and the operation energy consumption of the water pump need to be increased.

The indoor load of a conventional multi-connected air conditioning system is usually processed by the same heat source, and when a dehumidification mode needs to be operated in a transition season with low temperature and high relative humidity (such as the plum rain season of Yangtze river basin and the return south of south China), the comfort of the indoor environment is reduced due to the low outlet air temperature.

In large-space air-conditioning occasions such as offices and the like, due to the fact that the functions and positions of rooms are different, the refrigeration and heating requirements of different rooms are not synchronous at the tail ends, and the conventional multi-split air-conditioning system cannot achieve different refrigeration and heating modes of different tail ends.

In order to realize the advantages of the two tail end form multi-split air conditioners and solve the problem of reheating dehumidification in a transition season, the requirement for improving the energy efficiency of the system can be met, and the popularization and application of the use of the refrigerant with low GWP, high energy efficiency and certain combustibility can be met.

The present invention has been made in view of this situation.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects of the prior art and provide a refrigeration system and a control method for solving the problem of low system energy efficiency caused by secondary heat exchange and low water supply temperature of a conventional water multi-connected system.

In order to solve the above technical problems, a first objective of the present invention is to provide a refrigeration system, which includes a refrigerant circulation loop and a water circulation loop;

the refrigerant circulating loop comprises a first compression cylinder, a second compression cylinder and a third compression cylinder; the exhaust port of the first compression cylinder, the exhaust port of the second compression cylinder and the exhaust port of the third compression cylinder are connected through a first connecting pipe, the first connecting pipe is connected with a first interface of a four-way valve, the air suction port of the first compression cylinder and the air suction port of the second compression cylinder are respectively connected through a second connecting pipe, and the second connecting pipe is connected with a second interface of the four-way valve; a third interface of the four-way valve is connected with a first end of an outdoor heat exchanger, a second end of the outdoor heat exchanger is connected with a first end of a flash evaporator, a second end of the flash evaporator is connected with a first end of a first intermediate heat exchanger, and a second end of the first intermediate heat exchanger is connected with the second connecting pipe; the third end of the flash evaporator is connected with the first end of a second intermediate heat exchanger, and the second end of the second intermediate heat exchanger is connected with the fourth end of the four-way valve; the fourth end of the flash evaporator is connected with the air suction port of the third compression cylinder; a first control valve is arranged on a pipeline between the second end of the first intermediate heat exchanger and the second connecting pipe, and a second control valve is arranged on the second connecting pipe between the air suction port of the first compression cylinder and the air suction port of the second compression cylinder;

the refrigerant circulation loop further comprises a third connecting pipe, a first end of the third connecting pipe is connected with the first connecting pipe, and a second end of the third connecting pipe is arranged on a pipeline between the first control valve and the first intermediate heat exchanger; a third control valve is arranged on the third connecting pipe;

the water circulation loop is coupled with the first intermediate heat exchanger and the second intermediate heat exchanger respectively; the water circulation loop comprises a plurality of indoor heat exchange assemblies which are respectively arranged in a plurality of indoor spaces, each indoor heat exchange assembly comprises a first indoor heat exchanger and a second indoor heat exchanger which are sequentially arranged along the air circulation direction, the first indoor heat exchanger is positioned on the leeward side, and the second indoor heat exchanger is positioned on the windward side;

in different operation modes, the first intermediate heat exchanger exchanges heat with one indoor heat exchanger in each indoor heat exchange assembly through the water circulation loop, and the second intermediate heat exchanger exchanges heat with the other indoor heat exchanger in each indoor heat exchange assembly through the water circulation loop;

or the first intermediate heat exchanger exchanges heat with all indoor heat exchangers in a part of outdoor heat exchange assemblies simultaneously through the water circulation loop; and the second intermediate heat exchanger exchanges heat with all indoor heat exchangers in the other part of outdoor heat exchange assemblies simultaneously through the water circulation loop.

Further optionally, the water circulation loop includes a first circulation water outlet pipe, a first circulation water return pipe, a second circulation water outlet pipe and a second circulation water return pipe; the first circulating water outlet pipe and the first circulating water return pipe form a first main loop, and the first main loop is coupled with the first intermediate heat exchanger; the second circulating water outlet pipe and the second circulating water return pipe form a second main loop, and the second main loop is coupled with the second intermediate heat exchanger;

a plurality of first branch water paths are arranged between the first circulating water outlet pipe and the second circulating water outlet pipe, and a plurality of second branch water paths are arranged between the first circulating water return pipe and the second circulating water return pipe;

the first ends of all indoor heat exchangers in each heat exchange assembly are respectively connected with a first branch water channel, and the second ends of all indoor heat exchangers in each heat exchange assembly are respectively connected with a second branch water channel;

and three-way valves are respectively arranged between the first branch water path and the first ends of all indoor heat exchangers of each indoor heat exchange assembly and between the second branch water path and the second ends of all indoor heat exchangers in each indoor heat exchange assembly.

Further optionally, a first circulation pump is arranged on the first main loop, and a second circulation pump is arranged on the second main loop.

Further optionally, the refrigerant circulation loop includes three independent compressors, and each compressor is provided with a compression cylinder.

Further optionally, the refrigerant circulation loop includes a compressor, the compressor is a three-cylinder three-suction single-row compressor, three compression cylinders of the compressor are relatively independent and have independent suction ports, exhaust air of the three compression cylinders is discharged from the compressor through an exhaust port of the compressor after being converged inside the compressor, and the exhaust port of the compressor is connected to the first port of the four-way valve.

Further optionally, the displacement of the first compression cylinder is Va, and the displacement of the second compression cylinder is Vb, where: the value range of Va/Va is 0.5-2.

Further optionally, the displacement of the third compression cylinder is Vc, and it is satisfied that: the value range of Vc/(Va + Vb) is 0.05-0.3.

Further optionally, the heat exchange area of the first intermediate heat exchanger is directly proportional to the displacement of the first compression cylinder, and the heat exchange area of the second intermediate heat exchanger is directly proportional to the displacement of the second compression cylinder.

Further optionally, a first throttling device is arranged between the second end of the outdoor heat exchanger and the first end of the flash evaporator, and a second throttling device is arranged between the second end of the flash evaporator and the first end of the first intermediate heat exchanger; and a third throttling device is arranged between the third end of the flash evaporator and the second intermediate heat exchanger.

Further optionally, the outdoor heat exchanger is an air-cooled heat exchanger or a water-cooled heat exchanger;

and/or the first intermediate heat exchanger and the second intermediate heat exchanger are plate heat exchangers, double-pipe heat exchangers or high-efficiency tank heat exchangers;

and/or the first indoor heat exchanger and the second indoor heat exchanger are surface air coolers.

Further optionally, the refrigerant used in the refrigerant circulation circuit is selected from the group consisting of non-flammable refrigerants, flammable low GWP refrigerants, and mixtures thereof.

A second object of the present invention is to propose a control method using the above refrigeration system,

under different operation modes, the first intermediate heat exchanger is controlled to exchange heat with one indoor heat exchanger in each indoor heat exchange assembly through the water circulation loop, and the second intermediate heat exchanger exchanges heat with the other indoor heat exchanger in each indoor heat exchange assembly through the water circulation loop;

or the first intermediate heat exchanger is controlled to simultaneously exchange heat with all indoor heat exchangers in a part of outdoor heat exchange assemblies through the water circulation loop; and the second intermediate heat exchanger exchanges heat with all indoor heat exchangers in the other part of outdoor heat exchange assemblies simultaneously through the water circulation loop.

A third objective of the present invention is to provide a further control method using the above refrigeration system, wherein the connection state of the four-way valve and the communication state of the three-way valves on the first branch water paths and the second branch water paths are controlled by controlling the opening and closing of the first control valve, the second control valve and the third control valve, so that the first intermediate heat exchanger exchanges heat with one indoor heat exchanger in each of the indoor heat exchange assemblies through the first main loop, and the second intermediate heat exchanger exchanges heat with another indoor heat exchanger in each of the indoor heat exchange assemblies through the second main loop;

or the first intermediate heat exchanger exchanges heat with all indoor heat exchangers in a part of the outdoor heat exchange assemblies through a first main loop at the same time; and the second intermediate heat exchanger exchanges heat with all indoor heat exchangers in the other part of the outdoor heat exchange assembly through a second main loop at the same time.

Further optionally, in the cooling mode, the four-way valve is controlled to be in a first conduction state, the first control valve is controlled to be opened, and the second control valve and the third control valve are controlled to be closed;

and controlling the first circulating water outlet pipe to be communicated with the first ends of all the first indoor heat exchangers, controlling the first circulating water return pipe to be communicated with the second ends of all the first indoor heat exchangers, controlling the second circulating water outlet pipe to be communicated with the first ends of all the second indoor heat exchangers, and controlling the second circulating water return pipe to be communicated with the second ends of all the second indoor heat exchangers, so that the first intermediate heat exchanger exchanges heat with all the first indoor heat exchangers through the first main loop, and the second intermediate heat exchanger exchanges heat with all the second indoor heat exchangers through the second main loop.

Further optionally, in the heating mode, the four-way valve is controlled to be in a second conduction state, the first control valve is controlled to be closed, and the second control valve and the third control valve are controlled to be opened;

and controlling the first circulating water outlet pipe to be communicated with the first ends of all the second indoor heat exchangers, controlling the first circulating water return pipe to be communicated with the second ends of all the second indoor heat exchangers, controlling the second circulating water outlet pipe to be communicated with the first ends of all the first indoor heat exchangers, controlling the second circulating water return pipe to be communicated with the second ends of all the first indoor heat exchangers, so that the first intermediate heat exchangers exchange heat with all the second indoor heat exchangers through the first main loop, and the second intermediate heat exchangers exchange heat with all the first indoor heat exchangers through the second main loop.

Further optionally, in a dehumidification mode, the four-way valve is controlled to be in a first conduction state, the first control valve is controlled to be closed, and the second control valve and the third control valve are controlled to be opened;

and controlling the first circulating water outlet pipe to be communicated with the first ends of all the first indoor heat exchangers, controlling the first circulating water return pipe to be communicated with the second ends of all the first indoor heat exchangers, controlling the second circulating water outlet pipe to be communicated with the first ends of all the second indoor heat exchangers, and controlling the second circulating water return pipe to be communicated with the second ends of all the second indoor heat exchangers, so that the first intermediate heat exchangers exchange heat with all the first indoor heat exchangers through the first main loop, and the second intermediate heat exchangers exchange heat with all the second indoor heat exchangers through the second main loop.

Further optionally, in the heat recovery mode, the four-way valve is controlled to be in a first conduction state, the first control valve is controlled to be closed, and the second control valve and the third control valve are controlled to be opened;

the first circulating water outlet pipe is controlled to be communicated with first ends of all indoor heat exchangers in a part of outdoor heat exchange assemblies, and the first circulating water return pipe is controlled to be communicated with second ends of all indoor heat exchangers in the part of outdoor heat exchange assemblies; and controlling the second circulating water outlet pipe to be communicated with the first ends of all the indoor heat exchangers in the other part of the outdoor heat exchange assembly, and controlling the second circulating water return pipe to be communicated with the second ends of all the indoor heat exchangers in the part of the indoor heat exchange assembly, so that the first intermediate heat exchanger can exchange heat with all the indoor heat exchangers in the part of the outdoor heat exchange assembly at the same time through the first main loop, and the second intermediate heat exchanger can exchange heat with all the indoor heat exchangers in the other part of the outdoor heat exchange assembly at the same time through the second main loop.

After adopting the technical scheme, compared with the prior art, the invention has the following beneficial effects:

the technical effects of this application: the cascade heat exchange technology is applied to the scheme of a water multi-connected system, so that the problem of large refrigerant filling amount is solved, the energy efficiency of the system is improved, and the reheating and dehumidifying functions in transition seasons and the requirements of simultaneous refrigeration and heating operation of different air conditioning rooms of the large-space air conditioning system are met through system control.

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention, are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention without limiting the invention to the right. It is obvious that the drawings in the following description are only some embodiments, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:

FIG. 1: is a schematic cycle diagram of the refrigeration system in the refrigeration mode according to the embodiment of the invention.

FIG. 2: the present invention is a schematic diagram of a cycle in a heating mode of a refrigeration system.

FIG. 3: is a schematic cycle diagram of the refrigeration system in dehumidification mode according to an embodiment of the present invention.

FIG. 4: is a schematic cycle diagram of an embodiment of the refrigeration system in the heat recovery mode according to the embodiment of the present invention.

FIG. 5: is a schematic cycle diagram of another embodiment of the refrigeration system in the heat recovery mode according to the embodiment of the present invention.

It should be noted that the drawings and the description are not intended to limit the scope of the inventive concept in any way, but to illustrate it by a person skilled in the art with reference to specific embodiments.

Detailed Description

In the description of the present invention, it should be noted that the terms "inside", "outside", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," "contacting," and "communicating" are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The embodiment aims to solve the problems that a conventional water multi-connected system has low system energy efficiency caused by secondary heat exchange and low water supply temperature, the popularization of a low-GWP refrigerant with certain combustibility is limited due to the fact that the multi-connected system refrigerant at the tail end of the conventional refrigerant is large in filling amount and large in leakage risk, the technical problems of air cross and low reversing reliability of a dual-electronic expansion valve of the conventional dual-temperature system are solved, the problems of low air outlet temperature and poor comfort in dehumidification in transition seasons with low temperature and high relative humidity (such as the 'plum rain season' in Yangtze river basin and the 'return south day' in south China) are solved, and the contradiction that different rooms in large-space air conditioning areas such as offices and the like need refrigeration and heating operation at the same time is solved, so that a refrigeration system is provided and comprises a refrigerant circulation loop and a water circulation loop; the refrigerant circulating loop comprises a first compression cylinder 1a, a second compression cylinder 1b and a third compression cylinder 1 c; an exhaust port of the first compression cylinder 1a, an exhaust port of the second compression cylinder 1b and an exhaust port of the third compression cylinder 1c are connected through a first connecting pipe 11a, the first connecting pipe 11a is connected with a first interface of the four-way valve 2, an air suction port of the first compression cylinder 1a and an air suction port of the second compression cylinder 1b are respectively connected through a second connecting pipe 11b, and the second connecting pipe 11b is connected with a second interface of the four-way valve 2; a third interface of the four-way valve 2 is connected with a first end of the outdoor heat exchanger 3, a second end of the outdoor heat exchanger 3 is connected with a first end of the flash evaporator 10, a second end of the flash evaporator 10 is connected with a first end of the first intermediate heat exchanger 5a, and a second end of the first intermediate heat exchanger 5a is connected with a second connecting pipe 11 b; a third end of the flash evaporator 10 is connected with a first end of a second intermediate heat exchanger 5b, and a second end of the second intermediate heat exchanger 5b is connected with a fourth end of the four-way valve 2; the fourth end of the flash evaporator 10 is connected with the air suction port of the third compression cylinder 1 c; a first control valve 6a is arranged on a pipeline between the second end of the first intermediate heat exchanger 5a and the second connecting pipe 11b, and a second control valve 6b is arranged on the second connecting pipe 11b between the suction port of the first compression cylinder 1a and the suction port of the second compression cylinder 1 b;

the refrigerant circulation loop further comprises a third connecting pipe 11c, a first end of the third connecting pipe 11c is connected with the first connecting pipe 11a, and a second end of the third connecting pipe 11c is arranged on a pipeline between the first control valve 6a and the first intermediate heat exchanger 5 a; a third control valve 6c is arranged on the third connecting pipe 11 c; a first throttling device 4a is arranged between the second end of the outdoor heat exchanger 3 and the first end of the flash evaporator 10, and a second throttling device 4b is arranged between the second end of the flash evaporator 10 and the first end of the first intermediate heat exchanger 5 a; a third throttling device 4c is arranged between the third end of the flash evaporator 10 and the second intermediate heat exchanger 5 b. The first, second and third throttling means may optionally be electronic expansion valves. The first control valve 6a, the second control valve 6b, and the third control valve 6c may be selected as two-way valves.

The water circulation loop is respectively coupled with the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5 b; the water circulation loop comprises a plurality of indoor heat exchange assemblies which are respectively arranged in a plurality of indoor spaces, each indoor heat exchange assembly comprises a first indoor heat exchanger and a second indoor heat exchanger which are sequentially arranged along the air circulation direction, the first indoor heat exchanger is positioned on the leeward side, and the second indoor heat exchanger is positioned on the windward side; in this embodiment, two indoor spaces are taken as an example, each indoor space is provided with one indoor unit, each indoor unit is provided with one indoor heat exchange assembly, each indoor heat exchange assembly comprises two indoor heat exchangers, that is, one room comprises a first indoor heat exchanger 71a and a second indoor heat exchanger 71b, and the first indoor heat exchanger 71a and the second indoor heat exchanger 71b are sequentially arranged along the air flowing direction, wherein the first indoor heat exchanger 71a is located on the leeward side, and the second indoor heat exchanger 71b is located on the windward side. The other room includes a first indoor heat exchanger 72a and a second indoor heat exchanger 72b, and 72a and 72b are sequentially disposed in the air flow direction, wherein 72a is located on the leeward side and 72b is located on the windward side. It should be noted that, in practical applications, more than 2 indoor units may be connected to the refrigeration system, and the present embodiment is not limited to the case of connecting two indoor units, so as to limit the protection scope of the present invention.

Under different operation modes, the first intermediate heat exchanger 5a exchanges heat with one indoor heat exchanger in each indoor heat exchange assembly through a water circulation loop, and the second intermediate heat exchanger 5b exchanges heat with the other indoor heat exchanger in each indoor heat exchange assembly through a water circulation loop; or, the first intermediate heat exchanger 5a exchanges heat with all indoor heat exchangers in a part of outdoor heat exchange assemblies simultaneously through the water circulation loop; the second intermediate heat exchanger 5b exchanges heat with all the indoor heat exchangers in the other part of the outdoor heat exchange assembly simultaneously through the water circulation loop.

Specifically, the refrigerant circulation loop of the present embodiment includes one compressor 1 in some specific embodiments, as shown in fig. 1 to 5, the compressor 1 is a three-cylinder three-suction single-row compressor, three compression cylinders of the compressor 1 are relatively independent and have independent suction ports, exhaust air of the three compression cylinders is merged inside the compressor 1 and then discharged out of the compressor 1 through an exhaust port of the compressor 1, and the exhaust port of the compressor is connected to a first port of the four-way valve 2. In other embodiments, the refrigerant circulation circuit includes three independent compressors, each having a respective compression cylinder. After the exhaust of each compression cylinder is converged, the exhaust is connected with an outdoor heat exchanger 3 through a four-way valve 2, and meanwhile, a connecting pipe is led out to connect the exhaust of a compressor with a first intermediate heat exchanger 5 a; two suction ports of the compressor are respectively connected with outlets of the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5b, and a suction port of the third compression cylinder 1c is connected with an air outlet of the flash evaporator 10.

In the present embodiment, for example, a compressor is provided, and as shown in fig. 1-5, the compressor 1 has three independent compression cylinders 1a, 1b, 1c (including two main cylinders and a parallel cylinder), whose displacement amounts are Va and Vb, respectively, and the value of (Va/Vb) is between 0.5 and 2. The compression cylinder connected with the flash evaporator 10 is a parallel cylinder, the discharge capacity of the parallel cylinder is Vc, and the value range of Vc/(Va + Vb) is 0.05-0.3, preferably 0.06-0.18. The displacement ratio of the first compression cylinder and the second compression cylinder is limited in the range so as to be matched with indoor windward side and leeward side heat exchangers, and the displacement of the third compression cylinder and the displacement of the sum of the first compression cylinder and the second compression cylinder are limited in the range so as to better exert the advantages of parallel compression, so that a gas-liquid separator can be realized in the medium-pressure flash evaporator. The heat exchange area of the first intermediate heat exchanger 5a is in direct proportion to the displacement of the first compression cylinder 1a, and the heat exchange area of the second intermediate heat exchanger 5b is in direct proportion to the displacement of the second compression cylinder 1 b.

The exhaust of three compression cylinders is joined in the shell of the compressor 1 through a first connecting pipe 11a and then connected with a D pipe (a first interface) of the four-way valve 2 through an exhaust port of the compressor 1, an E pipe (a fourth interface) of the four-way valve is communicated with one end of a second intermediate heat exchanger 5b, an S pipe (a second interface) of the four-way valve 2 is connected with one suction port of the compressor 1, a C pipe (a third interface) of the four-way valve is connected with one end of an outdoor heat exchanger 3, meanwhile, two suction pipes of the compressor 1 are connected through a second connecting pipe 11b, and a second control valve 6b is arranged on the second connecting pipe 11b and connected with each other; a third connection pipe 11c is drawn from the discharge pipe of the compressor, and the discharge pipe of the compressor is connected to the first intermediate heat exchanger 5a, and a third control valve 6c is provided on the third connection pipe 11 c. The second connection pipe 11b is connected to the first intermediate heat exchanger 5a through the second control valve 6 a.

The outdoor heat exchanger 3 is an air-cooled or water-cooled heat exchanger, and the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5b are heat exchangers for exchanging heat between the refrigerant and the tail-end circulating water, and can be plate heat exchangers, double-pipe heat exchangers or high-efficiency tank heat exchangers and other structural forms. The indoor heat exchangers 71 and 72 are surface coolers.

Further optionally, the water circulation loop includes a first circulation water outlet pipe, a first circulation water return pipe, a second circulation water outlet pipe and a second circulation water return pipe; the first circulating water outlet pipe and the first circulating water return pipe form a first main loop, and the first main loop is coupled with the first intermediate heat exchanger 5 a; the second circulating water outlet pipe and the second circulating water return pipe form a second main loop, and the second main loop is coupled with the second intermediate heat exchanger 5 b; the first main loop is provided with a first circulating pump 8a, and the second main loop is provided with a second circulating pump 8 b. A plurality of first branch water paths are arranged between the first circulating water outlet pipe and the second circulating water outlet pipe, and a plurality of second branch water paths are arranged between the first circulating water return pipe and the second circulating water return pipe; the first ends of all indoor heat exchangers in each heat exchange assembly are respectively connected with a first branch water channel, and the second ends of all indoor heat exchangers in each heat exchange assembly are respectively connected with a second branch water channel; and three-way valves are respectively arranged between the first branch water path and the first ends of all indoor heat exchangers of each indoor heat exchange assembly and between the second branch water path and the second ends of all indoor heat exchangers in each indoor heat exchange assembly, and the three-way valves have the functions of water distribution and water collection.

The refrigerant used in the refrigerant circulation circuit in the embodiment is applicable to refrigerants with certain combustibility and low GWP values such as R32, R152a, R717, R1234ze (E) and the like and mixtures thereof besides conventional non-flammable refrigerants.

In the control method of the refrigeration system, the first intermediate heat exchanger 5a is controlled to exchange heat with one indoor heat exchanger in each indoor heat exchange assembly through the water circulation loop, and the second intermediate heat exchanger 5b is controlled to exchange heat with another indoor heat exchanger in each indoor heat exchange assembly through the water circulation loop in different operation modes; or, controlling the first intermediate heat exchanger 5a to exchange heat with all indoor heat exchangers in a part of outdoor heat exchange assemblies through the water circulation loop; the second intermediate heat exchanger 5b exchanges heat with all the indoor heat exchangers in the other part of the outdoor heat exchange assembly simultaneously through the water circulation loop.

Specifically, the connection state of the four-way valve is controlled by controlling the opening and closing conditions of the first control valve, the second control valve and the third control valve, and the communication state of three-way valves positioned on the plurality of first branch water paths and the plurality of second branch water paths is controlled, so that the first intermediate heat exchanger 5a exchanges heat with one indoor heat exchanger in each indoor heat exchange assembly through the first main loop, and the second intermediate heat exchanger 5b exchanges heat with the other indoor heat exchanger in each indoor heat exchange assembly through the second main loop;

or, the first intermediate heat exchanger 5a exchanges heat with all indoor heat exchangers in a part of outdoor heat exchange assemblies through the first main loop at the same time; the second intermediate heat exchanger 5b exchanges heat with all the indoor heat exchangers in the other part of the outdoor heat exchange assembly simultaneously through the second main loop.

The refrigeration system of the embodiment can realize refrigeration, heating, heat recovery and reheating dehumidification operation modes through the control valve arranged in the system and the adjustment of the flow of the water pump. The refrigeration and heating modes can realize double water supply temperature, the heat transfer temperature difference between indoor air and the heat exchanger is reduced by utilizing the cascade heat exchange principle, the irreversible loss is reduced, and the system energy efficiency is effectively improved. Meanwhile, the indoor heat exchanger on the windward side is used for refrigerating and dehumidifying during dehumidification, and the heat exchanger on the leeward side is used for heating and warming, so that the problems of low air outlet temperature and poor comfort during dehumidification in a transition season with low temperature and high relative humidity (such as the plum rain season of Yangtze river basin and the return south day of south China) are solved, refrigeration of one part of rooms is realized, heating of the other part of rooms is realized, and the contradiction that different rooms in a large-space air-conditioning area need refrigeration and heating operation at the same time is solved. In addition, the flash evaporator and the compression cylinder connected with the flash evaporator play roles in supplementing air and increasing enthalpy, ensuring the supply and regulation of the refrigerant and fully playing a role in heat exchange area of the condenser.

Further optionally, in the cooling mode, the four-way valve is controlled to be in a first conduction state, the first control valve is controlled to be opened, and the second control valve and the third control valve are controlled to be closed; and the first circulating water outlet pipe is controlled to be communicated with the first ends of all the first indoor heat exchangers, the first circulating water return pipe is controlled to be communicated with the second ends of all the first indoor heat exchangers, the second circulating water outlet pipe is controlled to be communicated with the first ends of all the second indoor heat exchangers, and the second circulating water return pipe is controlled to be communicated with the second ends of all the second indoor heat exchangers, so that the first intermediate heat exchanger 5a exchanges heat with all the first indoor heat exchangers through the first main loop, and the second intermediate heat exchanger 5b exchanges heat with all the second indoor heat exchangers through the second main loop.

Specifically, when operating in the cooling mode, as shown in fig. 1, the four-way valve 2 is in the first conduction state, the high-temperature and high-pressure exhaust gas of the compressor enters the outdoor heat exchanger 3 through the four-way valve 2, condensing and releasing heat in the outdoor heat exchanger 3 to obtain high-temperature and high-pressure refrigerant subcooled liquid, opening the first throttling device 4a (the opening degree of the first throttling device 4a is determined by the intermediate pressure in the flash evaporator 10, and referring to the saturation temperature corresponding to the intermediate pressure (condenser outlet temperature plus (high-temperature evaporation temperature plus low-temperature evaporation temperature)/2), wherein the refrigerant is subjected to primary throttling by the first throttling device 4a and then is changed into a two-phase state to enter the flash evaporator 10, the refrigerant in the gas-liquid two-phase state is separated in the flash evaporator 10 and then is divided into a saturated gas phase and a saturated liquid phase, the refrigerant saturated gas enters a parallel cylinder air suction port through a pipeline on the upper part of the flash evaporator 10 and is changed into high-temperature and high-pressure gas after being compressed in the parallel cylinder to be mixed with exhaust gas of the two main cylinders. The refrigerant saturated liquid is subjected to secondary throttling and pressure reduction through the second throttling device 4b and the third throttling device 4c and then changed into a low-temperature and low-pressure refrigerant two-phase state, the low-temperature and low-pressure refrigerant respectively enters the second intermediate heat exchanger 5b and the first intermediate heat exchanger 5a, the low-temperature and low-pressure refrigerant respectively exchanges heat with cold water coming out of the indoor heat exchanger in the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5b, and the refrigerant is evaporated and absorbs heat and is changed into a low-temperature and low-pressure refrigerant saturated or superheated gas state. In this mode, the third control valve 6c and the second control valve 6b are in a closed state, the first control valve 6a is in a conducting state, low-pressure refrigerant gas coming out of the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5b respectively enters the suction ports of the two main cylinders of the compressor through the first control valve 6a and the four-way valve 2, and low-pressure gaseous refrigerant is compressed into high-temperature high-pressure refrigerant gas in the two cylinders respectively and discharged to complete the whole refrigeration cycle. Under the refrigeration running mode, the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5b exchange heat with circulating water which comes out of the indoor heat exchangers on the indoor leeward side and the indoor heat exchangers on the windward side respectively, and the temperature of chilled water passing through the second intermediate heat exchanger 5b is higher than that of chilled water passing through the first intermediate heat exchanger 5a by matching the configuration of the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5b and adjusting the flow of the first circulating pump and the flow of the second circulating pump 8b, so that the energy gradient utilization effect of the refrigerant side and the water side can be realized. That is, the evaporation temperature of the second intermediate heat exchanger 5b is higher than that of the conventional refrigeration system, and the evaporation temperature of the first intermediate heat exchanger 5a is equivalent to that of the conventional refrigeration system, so that the energy efficiency of the refrigeration system can be improved. In the indoor heat exchanger, the temperature of the water on the windward side is higher than that of the water on the leeward side, and the indoor air to be treated is cooled by the high-temperature indoor heat exchanger and then exchanges heat with the low-temperature indoor heat exchanger, so that the heat exchange temperature difference is reduced, the irreversible heat exchange loss is reduced, and the system energy efficiency is effectively improved. In the mode, the second circulating pump 8b pumps indoor return water into the second intermediate heat exchanger 5b to exchange heat with the refrigerant and then reduce the temperature of the indoor return water into medium-temperature chilled water, the medium-temperature chilled water coming out of the second intermediate heat exchanger 5b enters the indoor windward side heat exchangers 72b and 71b through the three-way valves 9h and 9c respectively to perform primary cooling treatment on air in a refrigerating room, and the chilled water coming out of the indoor windward side heat exchangers 72b and 71b enters the inlet of the second circulating pump 8b through the three-way valves 9i and 9d respectively and is sent out under the action of the second circulating pump 8 b; the first circulating pump 8a is cooled down to low-temperature chilled water after heat exchange with the refrigerant in pumping indoor return water to the first intermediate heat exchanger 5a, the low-temperature chilled water coming out of the first intermediate heat exchanger 5a enters the indoor leeward side heat exchanger 72a and 71a through the three-way valve 9f and 9a respectively, air obtained after primary cooling treatment of the windward side heat exchanger is further cooled and dehumidified, the chilled water coming out of the indoor windward side heat exchanger 72a and 71a enters the inlet of the first circulating pump 8a through the three-way valve 9e and 9b respectively, and the chilled water is sent out under the action of the first circulating pump 8 a.

Further optionally, in the heating mode, the four-way valve 2 is controlled to be in a second conduction state, the first control valve is controlled to be closed, and the second control valve and the third control valve are controlled to be opened; and controlling the first circulating water outlet pipe to be communicated with the first ends of all the second indoor heat exchangers, controlling the first circulating water return pipe to be communicated with the second ends of all the second indoor heat exchangers, controlling the second circulating water outlet pipe to be communicated with the first ends of all the first indoor heat exchangers, and controlling the second circulating water return pipe to be communicated with the second ends of all the first indoor heat exchangers, so that the first intermediate heat exchanger 5a exchanges heat with all the second indoor heat exchangers through the first main loop, and the second intermediate heat exchanger 5b exchanges heat with all the first indoor heat exchangers through the second main loop.

Specifically, when the heating mode is operated, the four-way valve 2 is in the second conduction state as shown in fig. 2, the third control valve 6c and the second control valve 6b are opened, and the first control valve 6a is closed. One part of high-temperature and high-pressure exhaust gas of the compressor enters an outdoor second intermediate heat exchanger 5b through a four-way valve 2, the other part of the high-temperature and high-pressure exhaust gas enters a first intermediate heat exchanger 5a through a third control valve 6c, the heat is condensed and released in the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5b to become high-temperature and high-pressure refrigerant supercooled liquid, at the moment, a second throttling device 4b and a third throttling device 4c are opened (the opening degrees of the second throttling device 4b and the third throttling device 4c are determined by intermediate pressure in a flash evaporator 10 and refrigerant flow distribution in the two heat exchangers), the refrigerant is subjected to one-stage throttling by the second throttling device 4b and the third throttling device 4c to become two-phase state refrigerant and enters the flash evaporator 10, the two-phase refrigerant is separated into two states of saturated gas and saturated liquid after gas-liquid separation in the flash evaporator 10, and the saturated gas of the refrigerant enters a parallel cylinder suction port through a pipeline at the upper part of the flash evaporator 10, the refrigerant is compressed in the parallel cylinders and then changed into high-temperature high-pressure gas, the high-temperature high-pressure gas and the refrigerant saturated liquid discharged from the two main cylinders are converged, the refrigerant saturated liquid is subjected to secondary throttling and pressure reduction by the second throttling device 4b, the refrigerant is changed into a low-temperature low-pressure refrigerant two-phase state, the refrigerant enters the heat exchanger and enters the outdoor heat exchanger 3, and the low-temperature low-pressure refrigerant is evaporated and absorbs heat in the outdoor heat exchanger 3 and is changed into a low-temperature low-pressure refrigerant saturated or superheated gas state. The low-pressure refrigerant gas from the outdoor heat exchanger 3 enters two main cylinder air suction ports of the compressor through the four-way valve 2, and the low-pressure gaseous refrigerant is respectively compressed into high-temperature high-pressure refrigerant gas in two cylinders, then is discharged from an air outlet and is mixed with parallel cylinder exhaust gas, so that the whole refrigeration cycle is completed. In the heating operation mode, the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5b respectively exchange heat with circulating water from the indoor heat exchanger, and heated hot water is driven by the water pump to return to the indoor heat exchanger of the air-conditioning room to circularly heat indoor air. In the mode, the second circulating pump 8b pumps indoor return water into the second intermediate heat exchanger 5b to exchange heat with the refrigerant and then heat the indoor return water into high-temperature hot water, the high-temperature hot water discharged from the second intermediate heat exchanger 5b enters the indoor leeward side heat exchangers 72a and 71a through the three-way valves 9f and 9a respectively to further heat the air heated by the windward side heat exchangers, and the hot water discharged from the indoor windward side heat exchangers 72a and 71a enters the inlet of the second circulating pump 8b through the three-way valves 9e and 9b respectively and is sent out under the action of the second circulating pump 8 b; the first circulating pump 8a pumps indoor return water into the first intermediate heat exchanger 5a to exchange heat with the refrigerant and then cool the indoor return water into medium-temperature hot water, and the medium-temperature hot water coming out of the first intermediate heat exchanger 5a enters the indoor windward side heat exchangers 72b and 71b through the three-way valves 9h and 9c respectively to heat the indoor return air preliminarily. The chilled water from the indoor windward heat exchangers 72b, 71b enters the inlet of the first circulation pump 8a through three-way valves 9i and 9d, respectively, and is sent out by the first circulation pump 8 a.

Further optionally, in the dehumidification mode, the four-way valve 2 is controlled to be in a first conduction state, the first control valve is controlled to be closed, and the second control valve and the third control valve are controlled to be opened; and the first circulating water outlet pipe is controlled to be communicated with the first ends of all the first indoor heat exchangers, the first circulating water return pipe is controlled to be communicated with the second ends of all the first indoor heat exchangers, the second circulating water outlet pipe is controlled to be communicated with the first ends of all the second indoor heat exchangers, and the second circulating water return pipe is controlled to be communicated with the second ends of all the second indoor heat exchangers, so that the first intermediate heat exchanger 5a exchanges heat with all the first indoor heat exchangers through the first main loop, and the second intermediate heat exchanger 5b exchanges heat with all the second indoor heat exchangers through the second main loop.

Specifically, when the dehumidification mode is operated, as shown in fig. 3, the four-way valve 2 is in the first conduction state as the same as the refrigeration condition, the third control valve 6c and the second control valve 6b are opened, and the first control valve 6a is closed. One part of high-temperature and high-pressure exhaust gas of the compressor enters an outdoor heat exchanger 3 through a four-way valve 2, the other part of the high-temperature and high-pressure exhaust gas enters a first intermediate heat exchanger 5a through a third control valve 6c, the high-temperature and high-pressure refrigerant subcooled liquid is formed by condensing heat in the outdoor heat exchanger 3 and the first intermediate heat exchanger 5a and changing the heat into high-temperature and high-pressure refrigerant subcooled liquid, the refrigerant subcooled liquid coming out of the outdoor heat exchanger 3 and the first intermediate heat exchanger 5a is subjected to primary throttling and pressure reduction by a first throttling device 4a and a third throttling device 4c respectively and then is changed into a gas-liquid two-phase state under intermediate pressure to enter a flash evaporator 10, the two-phase refrigerant after liquid-liquid separation in the flash evaporator 10 is divided into a saturated gas phase and a saturated liquid phase, the refrigerant saturated gas enters a parallel cylinder air suction port through a pipeline at the upper part of the flash evaporator 10, and is changed into high-temperature and high-pressure gas and then is merged with two exhaust gases of a main cylinder. The refrigerant saturated liquid is subjected to secondary throttling and pressure reduction by the second throttling device 4b, then is changed into a low-temperature low-pressure refrigerant, and then enters the second intermediate heat exchanger 5b, and the low-temperature low-pressure refrigerant is evaporated and absorbs heat in the second intermediate heat exchanger 5b to be changed into a low-temperature low-pressure refrigerant saturated or superheated gas state. The low-pressure refrigerant gas coming out of the second intermediate heat exchanger 5b enters two air suction ports of the compressor through the four-way valve 2 and the second control valve, and the low-pressure gaseous refrigerant is compressed into high-temperature high-pressure refrigerant gas in two cylinders and then discharged from an air outlet, so that the whole refrigerant cycle is completed. In the reheating and dehumidifying operation mode, the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5b respectively exchange heat with circulating water from the indoor heat exchanger. Wherein heat exchanger 5b in the middle of the second provides the refrigerated water for air conditioner room windward side heat exchanger as the evaporimeter and is used for cooling down dehumidification processing to indoor return air, heat exchanger 5a in the middle of the first is used for heating the return water of indoor leeward side heat exchanger as the condenser, the hot water is used for heating the low temperature air after indoor windward side heat exchanger cooling dehumidification processing, be used for improving indoor return air temperature through retrieving the condensation heat, satisfy the purpose that the season dehumidification of transition does not cool down, improve indoor environment thermal comfort, the problem that conventional reheat technical scheme energy consumption is high has been solved simultaneously. In the mode, the second circulating pump 8b pumps the indoor return water into the second intermediate heat exchanger 5b to exchange heat with the refrigerant and then cool the indoor return water into low-temperature chilled water, and the low-temperature chilled water coming out of the second intermediate heat exchanger 5b enters the indoor windward side heat exchangers 72b and 71b through the three-way valves 9h and 9c respectively to cool and dehumidify the indoor air. The chilled water coming out of the indoor windward side heat exchangers 72b and 71b respectively enters the inlet of the second circulating pump 8b after being converged by the three-way valves 9i and 9d, and is sent out under the action of the second circulating pump 8 b; the first circulating pump 8a is heated into high-temperature hot water after heat exchange is carried out between the indoor return water and the refrigerant in the first intermediate heat exchanger 5a, the high-temperature hot water coming out of the first intermediate heat exchanger 5a enters the indoor leeward side heat exchangers 72a and 71a through the three-way valves 9f and 9a respectively, air obtained after windward side cooling and dehumidifying treatment is heated and warmed, and the air supply temperature is improved to ensure indoor comfort. The chilled water from the indoor leeward side heat exchangers 72b, 71b enters the inlet of the first circulation pump 8a through three-way valves 9i and 9d, respectively, and is sent out by the first circulation pump 8 a.

Further optionally, in the heat recovery mode, the four-way valve 2 is controlled to be in a first conduction state, the first control valve is controlled to be closed, and the second control valve and the third control valve are controlled to be opened; controlling the first circulating water outlet pipe to be communicated with first ends of all indoor heat exchangers in a part of outdoor heat exchange assemblies, and controlling the first circulating water return pipe to be communicated with second ends of all indoor heat exchangers in the part of outdoor heat exchange assemblies; and controlling the second circulating water outlet pipe to be communicated with the first ends of all the indoor heat exchangers in the other part of the outdoor heat exchange assembly, and controlling the second circulating water return pipe to be communicated with the second ends of all the indoor heat exchangers in the part of the indoor heat exchange assembly, so that the first intermediate heat exchanger 5a can exchange heat with all the indoor heat exchangers in the part of the outdoor heat exchange assembly through the first main loop at the same time, and the second intermediate heat exchanger 5b can exchange heat with all the indoor heat exchangers in the other part of the outdoor heat exchange assembly through the second main loop at the same time.

Specifically, when the heat recovery mode is operated, as shown in fig. 4 and 5, the four-way valve 2 is in the first conduction state as the same as the cooling condition, the third control valve 6c and the second control valve 6b are opened, and the first control valve 6a is closed. One part of high-temperature and high-pressure exhaust gas of the compressor enters an outdoor heat exchanger 3 through a four-way valve 2, the other part of the high-temperature and high-pressure exhaust gas enters a first intermediate heat exchanger 5a through a third control valve 6c, the high-temperature and high-pressure refrigerant subcooled liquid is condensed and released in the outdoor heat exchanger 3 and the first intermediate heat exchanger 5a and is changed into high-temperature and high-pressure refrigerant subcooled liquid, the refrigerant subcooled liquid coming out of the outdoor heat exchanger 3 and the first intermediate heat exchanger 5a is changed into a medium-pressure two-phase state after being subjected to primary throttling and pressure reduction through a first throttling device 4a and a third throttling device 4c respectively and enters a flash evaporator 10, the two-phase refrigerant after gas-liquid separation in the flash evaporator 10 is separated into a saturated gas phase and a saturated liquid phase, the saturated gas of the refrigerant enters a parallel cylinder suction pipe through a pipeline at the upper part of the flash evaporator 10, and the saturated gas of the refrigerant is changed into high-temperature and high-pressure gas and is merged with the exhaust gas of two main cylinders after the parallel cylinders. The refrigerant saturated liquid is subjected to secondary throttling and pressure reduction by the second throttling device 4b and then is changed into a low-temperature and low-pressure refrigerant two-phase state, the low-temperature and low-pressure refrigerant enters the second intermediate heat exchanger 5b, and the low-temperature and low-pressure refrigerant is evaporated and absorbs heat in the second intermediate heat exchanger 5b and is changed into a low-temperature and low-pressure refrigerant saturated or superheated gas state. The low-pressure refrigerant gas coming out of the second intermediate heat exchanger 5b enters two main cylinder suction ports of the compressor through the four-way valve 2 and the second control valve, and the low-pressure gaseous refrigerant is respectively compressed into high-temperature high-pressure refrigerant gas in two cylinders and then discharged from the exhaust port to be converged with parallel cylinder exhaust gas, so that the whole refrigerant cycle is completed. In this mode, the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5b perform heat exchange with circulating water from the indoor heat exchanger, respectively. The second intermediate heat exchanger 5b serves as an evaporator to provide chilled water for the air-conditioning room heat exchangers 72a and 72b to refrigerate and cool the indoor return air, the first intermediate heat exchanger 5a serves as a condenser to heat the return water of the heating room, and the heated high-temperature hot water is sent back to the heating room to heat the indoor return air. The mode can solve the problem that the refrigeration and heating modes of different rooms of a large-space building are not synchronous, and can realize heat recovery and improve the energy efficiency of the system.

Fig. 4 is a specific embodiment of the water side heat exchange in the heat recovery mode, in which the second circulation pump 8b pumps the indoor return water into the second intermediate heat exchanger 5b to exchange heat with the refrigerant and then cool the indoor return water to low-temperature chilled water, and the low-temperature chilled water coming out of the second intermediate heat exchanger 5b enters the indoor heat exchangers 72b and 72a of one of the rooms through the three-way valves 9f and 9h, respectively, to cool or dehumidify the indoor air. The chilled water coming out of the indoor windward side heat exchangers 72b and 72a of one room respectively enters the inlet of the second circulating pump 8b after being converged by three-way valves 9i and 9e, and is sent out under the action of the second circulating pump 8 b; the first circulation pump 8a pumps the indoor return water of the other room into the first intermediate heat exchanger 5a to exchange heat with the refrigerant and then heats the water to high-temperature hot water, and the high-temperature hot water discharged from the first intermediate heat exchanger 5a enters the indoor heat exchangers 71b and 71a of the other room through the three-way valves 9c and 9a, respectively, to heat the air in the room. The chilled water from the indoor heat exchangers 71b and 71a enters the inlet of the first circulation pump 8a through the three-way valves 9d and 9b, respectively, and is sent out by the first circulation pump 8 a.

Fig. 5 shows another embodiment of the heat recovery mode, which is the same as the heat recovery mode refrigerant side form shown in fig. 4, except that the room for cooling and heating on the water side is different.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.