CN113465218A - Refrigerating system and control method - Google Patents

Abstract

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 problems that the conventional water multi-connected system has secondary heat exchange and the energy efficiency of the system is low due to low water supply temperature.

Description

Refrigerating system and control method

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 circulation loop comprises a first compression cylinder and a second compression cylinder; the exhaust port of the first compression cylinder is connected with a first interface of a first four-way valve, and a second interface of the first four-way valve is connected with the suction port of the first compression cylinder; the exhaust port of the second compression cylinder is connected with the first interface of a second four-way valve, and the second interface of the second four-way valve is connected with the suction port of the second compression cylinder; a third interface of the second four-way valve is connected with a first end of the outdoor radiator, a second end of the outdoor heat exchanger is respectively connected with a first end of a first intermediate heat exchanger and a first end of a second intermediate heat exchanger, a second end of the first intermediate heat exchanger is connected with a fourth interface of the first four-way valve, and a second end of the second intermediate heat exchanger is connected with a fourth interface of the second four-way valve;

the refrigerant circulation loop further comprises a connecting pipe, a first end of the connecting pipe is connected to a pipeline between the second four-way valve and the outdoor heat exchanger, a second end of the connecting pipe is connected to a pipeline between the second intermediate heat exchanger and the second four-way valve, the connecting pipe is respectively provided with a first control valve and a second control valve, and a third interface of the first four-way valve is connected to a pipeline between the first control valve and the second control valve;

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 first circulation water return pipe; the first circulating water outlet pipe and the second circulating water outlet 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 two independent compressors, and each of the compressors is provided with a compression cylinder.

Further optionally, the refrigerant circulation loop includes a compressor, the compressor is a dual-cylinder dual-suction dual-row compressor, two compression cylinders of the compressor are relatively independent and have independent suction ports, and exhaust gases of the two compression cylinders are respectively discharged from respective exhaust ports of the compressor.

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 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 second end of the outdoor heat exchanger is connected to a first end of a main pipeline, the second end of the main pipeline is connected to two branch pipelines, one of the branch pipelines is connected to a first end of the first intermediate heat exchanger, the other branch pipeline is connected to a first end of the second intermediate heat exchanger, the main pipeline is provided with a first throttling device, and the two branch pipelines are respectively provided with a second throttling device and a third throttling device.

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.

The invention also provides a control method adopting the 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.

The invention also provides a control method adopting the refrigeration system, which controls the connection state of the first four-way valve and the second four-way valve and the communication state of three-way valves 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 and the second 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.

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

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 first four-way valve is controlled to be in a second conduction state, the second four-way valves are controlled to be in first conduction states, the first control valve is controlled to be closed, and the second control valve is 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 a heat recovery mode, the first four-way valve is controlled to be in a second conduction state, the second four-way valves are controlled to be in first conduction states, the first control valve is controlled to be closed, and the second control valve is 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.

In the embodiment, in order to solve the problem of low system energy efficiency caused by the secondary heat exchange and low water supply temperature of the conventional water multi-connected system, and the popularization of the low GWP refrigerant with certain combustibility is limited due to the large refrigerant filling amount and large leakage risk of the multi-refrigerant end system of the conventional refrigerant, and solves the technical problems of low reliability of gas leakage and commutation of the double electronic expansion valve of the conventional double-temperature system, and solves the problems of low air-out temperature and poor comfort when dehumidifying in the transition seasons with low temperature and high relative humidity (such as the plum rain season of Yangtze river basin and the return south of south China), and solves the contradiction that different rooms in large-space air-conditioning areas such as offices and the like need to be cooled and heated simultaneously, therefore, a refrigeration system is proposed, as shown in fig. 1-5, including a refrigerant circulation loop and a water circulation loop; the refrigerant circulation loop comprises a first compression cylinder 1a and a second compression cylinder 1 b; the exhaust port of the first compression cylinder 1a is connected with the first interface of the first four-way valve 2a, and the second interface of the first four-way valve 2a is connected with the suction port of the first compression cylinder 1 a; the exhaust port of the second compression cylinder 1b is connected with the first interface of the second four-way valve 2b, and the second interface of the second four-way valve 2b is connected with the suction port of the second compression cylinder 1 b; a third interface of the second four-way valve 2b is connected with a first end of an outdoor radiator, a second end of the outdoor heat exchanger 3 is respectively connected with a first end of a first intermediate heat exchanger and a first end of a second intermediate heat exchanger, a second end of the first intermediate heat exchanger is connected with a fourth interface of the first four-way valve 2a, and a second end of the second intermediate heat exchanger is connected with a fourth interface of the second four-way valve 2 b;

the second end of the outdoor heat exchanger 3 is connected with the first end of the main pipeline, the second end of the main pipeline is connected with two branch pipelines, one branch pipeline is connected with the first end of the first intermediate heat exchanger, the other branch pipeline is connected with the first end of the second intermediate heat exchanger, the main pipeline is provided with a first throttling device 4a, and the two branch pipelines are respectively provided with a second throttling device 4b and a third throttling device 4 c. The first, second and third throttling means may optionally be electronic expansion valves.

The refrigerant circulation loop also comprises a connecting pipe 11, the first end of the connecting pipe 11 is connected to the pipeline between the second four-way valve 2b and the outdoor heat exchanger 3, the second end of the connecting pipe 11 is connected to the pipeline between the second intermediate heat exchanger and the second four-way valve 2b, the connecting pipe 11 is respectively provided with a first control valve 6a and a second control valve 6b, and the third interface of the first four-way valve 2a is connected to the pipeline between the first control valve 6a and the second control valve 6 b; the first control valve 6a and the second control valve 6b may be selected as two-way valves.

The water circulation loop is respectively coupled with the first intermediate heat exchanger and the second intermediate heat exchanger; 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 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.

Specifically, the refrigerant circulation circuit of the present embodiment includes a compressor 1 in some embodiments, as shown in fig. 1 to 5, the compressor 1 is a two-cylinder, two-suction, two-discharge compressor, two compression cylinders of the compressor 1 are relatively independent and have independent suction ports, and exhaust gases of the two compression cylinders are respectively discharged from respective exhaust ports of the compressor 1. In other embodiments, the refrigerant circulation circuit includes two independent compressors, each having a respective compression cylinder. Two exhaust ports of the compressors are connected with the outdoor heat exchanger 3 through two four-way reversing valves, namely, the exhaust port of one compressor is connected with a first interface of the first four-way valve 2a, the exhaust port of the other compressor is connected with a first interface of the second four-way valve 2b, and meanwhile, a connecting pipe is led out to connect the exhaust of the two compressors with the second intermediate heat exchanger 5 b; two suction ports of the compressor are respectively connected with outlets of the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5 b.

In the present embodiment, a compressor is taken as an example, as shown in fig. 1-5, the compressor 1 has two independent compression cylinders 1a and 1b, the displacement of the two compression cylinders is Va and Vb, respectively, and the value of (Va/Vb) is between 0.5 and 2; the displacement ratio of the first and second compression cylinders is limited in this range to match the indoor windward and leeward side heat exchangers. 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 compression cylinder with the displacement of Vb is connected with a D pipe (a first interface) of a second four-way valve 2b, an E pipe (a fourth interface) of the second four-way valve 2b is connected with a second end of a second control valve 6b, a second end of the second control valve 6b is connected with a second end of a second intermediate heat exchanger 5b, an S pipe (a second interface) of the first four-way valve 2a is connected with an air suction port of the first compression cylinder 1a, and an S pipe (a second interface) of the second four-way valve 2b is connected with an air suction port of the second compression cylinder 2 a. A pipe C (third port) of the second four-way valve 2b is simultaneously connected with the second end of the first control valve 6a and the first end of the outdoor heat exchanger 3; an exhaust port of the first compression cylinder 1a is connected to a D pipe (first port) of the first four-way valve 2a, an E pipe (fourth port) of the first four-way valve 2a is communicated to a second end of the first intermediate heat exchanger 5a, an S pipe (second port) of the first four-way valve 2a is connected to an air suction port of the first compression cylinder, a C pipe (third port) of the first four-way valve 2a is connected to a first end of the first control valve 6a and a first end of the second control valve 6b, and a second end of the first control valve 6a is connected to a C pipe (third port) of the second four-way valve 2b and a first end of the outdoor heat exchanger 3.

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

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.

The embodiment also provides a control method adopting the refrigeration system, and 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 controlling the first intermediate heat exchanger 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.

Specifically, the connection state of the first four-way valve 2a and the second four-way valve 2b is controlled by controlling the opening and closing conditions of the first control valve 6a and the second control valve 6b, and the communication state of three-way valves on a plurality of first branch water paths and a plurality of second branch water paths is controlled, so that the first intermediate heat exchanger exchanges heat with one indoor heat exchanger in each indoor heat exchange assembly through the first main loop, and the second intermediate heat exchanger 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 exchanges heat with all indoor heat exchangers in a part of outdoor heat exchange assemblies simultaneously through the first main loop; and the second intermediate heat exchanger 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.

Further optionally, in the cooling mode, the first four-way valve 2a and the second four-way valve 2b are controlled to be in the first conduction state, the first control valve 6a is controlled to be opened, and the second control valve 6b is controlled to be closed; 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 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.

Specifically, as shown in fig. 1, during the cooling mode operation, the first four-way valve 2a and the second four-way valve 2b are both in the first conduction state, the first control valve 6a is in the conduction state, and the second control valve 6b is in the closing state, one high-temperature and high-pressure exhaust gas of the compressor 1 passes through the first four-way valve 2a and the first control valve 6a respectively and joins another high-temperature and high-pressure exhaust gas passing through the second four-way valve 2b, and then enters the outdoor heat exchanger 3, where the refrigerant is condensed and released into a high-temperature and high-pressure refrigerant sub-cooled liquid in the outdoor heat exchanger 3, at this time, the first throttling device 4a is fully opened, the liquid refrigerant passes through the second throttling device 4b and the third throttling device 4c, and then enters the second intermediate heat exchanger 5b and the first intermediate heat exchanger 5a respectively, and the refrigerant is changed into a low-temperature and high-pressure refrigerant two-phase state, and part of the low-temperature and low-pressure refrigerant in the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5b respectively and the cold water coming out of the indoor heat exchanger 3 The heat exchange is carried out, 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 low-pressure refrigerant gas coming out of the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5b enters the two suction ports of the compressor through the first four-way valve 2a and the second four-way valve 2b, respectively, and the low-pressure gaseous refrigerant is compressed into high-temperature high-pressure refrigerant gas in the two cylinders and the supplementary cylinder, respectively, and is 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 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 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 the 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 through the three-way valve 9e and the three-way valve 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 first four-way valve 2a and the second four-way valve 2b are controlled to be in the second conduction state, the first control valve 6a is controlled to be opened, and the second control valve 6b is controlled to be closed; and the first circulating water outlet pipe is controlled to be communicated with the first ends of all the second indoor heat exchangers, the first circulating water return pipe is controlled to be communicated with the second ends of all the second indoor heat exchangers, the second circulating water outlet pipe is controlled to be communicated with the first ends of all the first indoor heat exchangers, and the second circulating water return pipe is controlled 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.

Specifically, when the heating mode is operated, as shown in fig. 2, the first four-way valve 2a and the second four-way valve 2b are in the second conduction state, and the first control valve 6a is opened and the second control valve 6b is closed. One part of high-temperature and high-pressure exhaust air of the compressor enters an outdoor second intermediate heat exchanger 5b through a second four-way valve 2b, the other part of the high-temperature and high-pressure exhaust air enters a first intermediate heat exchanger 5a through a first four-way valve 2a, wherein the refrigerant with low condensation pressure enters the first intermediate heat exchanger 5a on the windward side, the refrigerant with high condensation pressure enters the second intermediate heat exchanger 5b on the leeward side, the two parts of the refrigerants are condensed and released in the first intermediate heat exchangers 5a and 5b respectively to become high-temperature and high-pressure refrigerant supercooled liquid, a heating double-condensation-temperature system is formed, and at the moment, the first throttling device 4a is fully opened. The two parts of refrigerant liquid are throttled and decompressed by a second throttling device 4b and a third throttling device 4c respectively to become a low-temperature low-pressure refrigerant two-phase state, and are converged into an outdoor heat exchanger 3, and the low-temperature low-pressure refrigerant is evaporated and absorbs heat in the outdoor heat exchanger 3 to become a low-temperature low-pressure refrigerant saturated or superheated gas state; part of the low-pressure refrigerant gas from the outdoor heat exchanger 3 enters the suction port of the corresponding cylinder of the compressor through the second four-way valve 2b, and the low-pressure gaseous refrigerant is compressed into high-temperature high-pressure refrigerant gas in the two cylinders, discharged from the exhaust port and enters the second intermediate heat exchanger 5 b; the other part of the refrigerant enters the suction port of the corresponding cylinder of the compressor through the first control valve 6a and the first four-way valve 2a, is compressed into high-temperature and high-pressure refrigerant gas in the corresponding cylinder, is discharged from the exhaust port and enters the first intermediate heat exchanger 5a, and therefore the whole cycle is completed. In the heating operation mode, the first intermediate heat exchanger 5a exchanges heat with circulating water coming out of the indoor heat exchanger on the leeward side of the indoor side, the second intermediate heat exchanger 5b exchanges heat with circulating water coming out of the indoor heat exchanger on the windward side of the indoor side, the water temperature on the leeward side is higher than that on the windward side, indoor air to be treated is treated by the heat exchanger with low condensation temperature and then exchanges heat with the indoor heat exchanger with high condensation temperature, a double-temperature system with indoor high and low condensation temperature is formed, the heat exchange temperature difference is reduced, and the irreversible heat exchange loss is reduced. 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 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 leeward 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 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 first four-way valve 2a is controlled to be in the second conduction state, the second four-way valves 2b are controlled to be in the first conduction state, the first control valve 6a is controlled to be closed, and the second control valve 6b is controlled to be opened; 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 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.

Specifically, when the dehumidification mode is operated, as shown in fig. 3, the first four-way valve 2a is in the second conduction state, the second four-way valve 2b is in the first conduction state as the same as the refrigeration condition, the first control valve 6a is closed, and the second control valve 6b is opened. One part of high-temperature and high-pressure exhaust gas of the compressor enters the outdoor heat exchanger 3 through the second four-way valve 2b, the other part of the high-temperature and high-pressure exhaust gas enters the first intermediate heat exchanger 5a through the first four-way valve 2a, the heat is condensed and released in the outdoor heat exchanger 3 and the first intermediate heat exchanger 5a to become high-temperature and high-pressure refrigerant supercooled liquid, at the moment, the second throttling device 4b is fully opened, the refrigerant supercooled liquid coming out of the outdoor heat exchanger 3 and the first intermediate heat exchanger 5a is throttled and reduced in pressure by the first throttling device 4a and the third throttling device 4c respectively to become low-temperature and medium-pressure two-phase refrigerant, and the low-temperature and medium-pressure refrigerant is mixed and then enters the second intermediate low-pressure heat exchanger 5b, and the low-temperature refrigerant is evaporated and absorbed in the second intermediate heat exchanger 5b to become low-temperature and low-pressure refrigerant saturated or superheated gas state; part of the low-pressure refrigerant gas from the second intermediate heat exchanger 5b enters a corresponding suction port of the compressor through the second four-way valve 2 b; the other part enters a corresponding suction port of the compressor through the second control valve 6b and the first four-way valve 2a, the two parts of low-pressure gaseous refrigerant are compressed into high-temperature high-pressure refrigerant gas in corresponding cylinders respectively, and the compressed high-temperature high-pressure gaseous refrigerant is discharged from corresponding exhaust ports to complete the whole refrigerant cycle. In the dehumidification operation mode, the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5b respectively exchange heat with circulating water discharged from the first indoor heat exchangers 71a and 72a and the second indoor heat exchangers 71b and 72 b. 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 first four-way valve 2a is controlled to be in the second conduction state, the second four-way valves 2b are controlled to be in the first conduction state, the first control valve 6a is controlled to be closed, and the second control valve 6b is 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 can simultaneously exchange heat with all the indoor heat exchangers in the part of the outdoor heat exchange assembly through the first main loop, and the second intermediate heat exchanger can simultaneously exchange heat with all the indoor heat exchangers in the other part of the outdoor heat exchange assembly through the second main loop.

Specifically, when the heat recovery mode is operated, as shown in fig. 4 and 5, the first four-way valve 2a is in the second conduction state, the second four-way valve 2b is in the first conduction state as the same as the cooling condition, the first control valve 6a is closed, and the second control valve 6b is opened. High-temperature and high-pressure exhaust gas of the compressor enters the outdoor heat exchanger 3 through the second four-way valve 2b, the other part of the exhaust gas enters the first intermediate heat exchanger 5a through the first four-way valve 2a, the exhaust gas is condensed and released in the outdoor heat exchanger 3 and the first intermediate heat exchanger 5a to become high-temperature and high-pressure refrigerant supercooled liquid, at the moment, the second throttling device 4b is fully opened, the refrigerant supercooled liquid coming out of the outdoor heat exchanger 3 and the first intermediate heat exchanger 5a is throttled and depressurized through the first throttling device 4a and the third throttling device 4c respectively to become a low-temperature and low-pressure refrigerant two-phase state and enters the second intermediate heat exchanger 5b after being mixed, and the low-temperature and low-pressure refrigerant is evaporated and absorbed heat in the second intermediate heat exchanger 5b to become a low-temperature and low-pressure refrigerant saturated or superheated gas state; part of the low-pressure refrigerant gas from the second intermediate heat exchanger 5b enters a corresponding suction port of the compressor through the second four-way valve 2 b; the other part enters the other cylinder of the compressor through the second control valve 6b and the first four-way valve 2a, the low-pressure gaseous refrigerant is compressed in the two corresponding cylinders respectively, and the compressed high-temperature high-pressure gaseous refrigerant is discharged from the corresponding exhaust port to complete the whole refrigerant cycle.

Fig. 4 shows a specific embodiment of the water side heat exchange in the heat recovery mode in which the first intermediate heat exchanger 5a and the second intermediate heat exchanger 5b exchange heat with the circulating water from the indoor side 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. 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 side heat exchangers 72b and 72a of one room 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.

Claims (16)

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

the refrigerant circulation loop comprises a first compression cylinder and a second compression cylinder; the exhaust port of the first compression cylinder is connected with a first interface of a first four-way valve, and a second interface of the first four-way valve is connected with the suction port of the first compression cylinder; the exhaust port of the second compression cylinder is connected with the first interface of a second four-way valve, and the second interface of the second four-way valve is connected with the suction port of the second compression cylinder; a third interface of the second four-way valve is connected with a first end of an outdoor radiator, a second end of the outdoor heat exchanger is respectively connected with a first end of a first intermediate heat exchanger and a first end of a second intermediate heat exchanger, a second end of the first intermediate heat exchanger is connected with a fourth interface of the first four-way valve, and a second end of the second intermediate heat exchanger is connected with a fourth interface of the second four-way valve;

the refrigerant circulation loop further comprises a connecting pipe, a first end of the connecting pipe is connected to a pipeline between the second four-way valve and the outdoor heat exchanger, a second end of the connecting pipe is connected to a pipeline between the second intermediate heat exchanger and the second four-way valve, the connecting pipe is respectively provided with a first control valve and a second control valve, and a third interface of the first four-way valve is connected to a pipeline between the first control valve and the second control valve;

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 recited in claim 2 or 3 wherein said refrigerant circuit includes two independent compressors, each of said compressors having a respective compression cylinder therein, wherein a discharge port of one of said compressors is connected to said first port of said first four-way valve, and a discharge port of the other of said compressors is connected to said first port of said second four-way valve.

5. A refrigeration system as claimed in claim 2 or 3, wherein said refrigerant circuit includes a compressor, said compressor is a two-cylinder, two-suction, two-discharge compressor, two compression cylinders of said compressor are relatively independent and have independent suction ports, and the exhaust of the two compression cylinders is discharged from the compressor through respective discharge ports.

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 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.

8. A refrigeration system as recited in claim 7 wherein said second end of said outdoor heat exchanger is connected to a first end of a main conduit, said second end of said main conduit being connected to two branch conduits, one of said branch conduits being connected to said first end of said first intermediate heat exchanger and the other of said branch conduits being connected to said first end of said second intermediate heat exchanger, said main conduit being provided with a first throttling means, and each of said two branch conduits being provided with a second throttling means and a third throttling means.

9. The refrigeration system of claim 8, 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 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.

10. A method as claimed in claim 1, wherein 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.

11. 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.

12. A control method using the refrigeration system according to any one of claims 2 to 10,

controlling the connection state of the first four-way valve and the second 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 and the second 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.

13. The control method of a refrigeration system as recited in claim 12, wherein in the refrigeration mode, the first four-way valve and the second four-way valve are both controlled to be in a first conduction state, the first control valve is controlled to be opened, and the second control valve is 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.

14. The control method of a refrigeration system as recited in claim 12, wherein in the heating mode, the first four-way valve and the second four-way valve are controlled to be in the second conducting state, the first control valve is controlled to be opened, and the second control valve is controlled to be closed;

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.

15. The control method of a refrigeration system as recited in claim 12, wherein in a dehumidification mode, the first four-way valve is controlled to be in the second conduction state, the second four-way valves are controlled to be in the first conduction state, the first control valve is controlled to be closed, and the second control valve is 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.

16. A control method for a refrigeration system as set forth in claim 12, wherein in the heat recovery mode, said first four-way valve is controlled to be in the second conduction state, said second four-way valves are controlled to be in the first conduction state, said first control valve is controlled to be closed, and said second control valve is 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.

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