A four-pipe air conditioning system with stepless adjustment of heating capacity

Abstract

The present invention relates to the field of air conditioning systems, and more specifically to a four-pipe air conditioning system with stepless adjustable heating capacity. The reversing circuit comprises a four-way reversing valve and a three-way valve, the E port of the four-way reversing valve is connected to the B1 port of the three-way valve, the outlet end of the compressor is connected to the D port of the four-way reversing valve, the S port of the four-way reversing valve is connected to the inlet end of a gas-liquid separator, the outlet end of the gas-liquid separator is connected to the inlet end of the compressor, the C port of the four-way reversing valve is connected to one end of an air-side heat exchanger, the other end of the air-side heat exchanger is connected to the B2 port of the three-way valve and a throttling circuit, the A port of the three-way valve is connected to one end of a hot water heat exchanger, the other end of the hot water heat exchanger is connected to the throttling circuit, the throttling circuit is connected to one end of a cold water heat exchanger, and the other end of the cold water heat exchanger is connected to the inlet end of the gas-liquid separator; the heating output capacity of the four-pipe unit can be steplessly adjusted.

Description

Technical Field

[0001] The invention relates to the field of air conditioning systems, and more specifically to a four-pipe air conditioning system with stepless adjustable heating capacity. Background Art

[0002] When the traditional four-pipe unit is in the working mode of producing both cold and hot water at the same time, not only is the heating capacity much greater than its cooling capacity, but the heating capacity cannot be adjusted. The heat demand of the air-conditioning terminal matched with the four-pipe unit is often much smaller than the cold demand. As a result, when the hot water reaches the target value, the cold water is often far from the target. The traditional four-pipe unit can only switch to the mode of producing only cold water to ensure normal cooling and prevent the hot water from continuing to heat up. Since the air-conditioning terminal consumes hot water in real time, after a period of time, the unit needs to switch back to the mode of producing both cold and hot water at the same time to make the hot water side meet the user's use needs. As mentioned above, the unit will constantly switch back and forth between the two modes to meet the user's daily use needs. Frequent switching modes will not only cause large fluctuations in the temperature of cold and hot water, affecting the user experience, but will also reduce the service life of the unit;

[0003] Based on the current situation of four-pipe control, a technology is needed to overcome the problem that the cooling and heating capacity of the four-pipe unit cannot match the cooling and heating demand of the terminal. By adjusting the heating capacity of the unit, the unit does not need to switch the working mode, avoiding fluctuations in the cold and hot water temperatures and extending the service life of the unit. Summary of the invention

[0004] The purpose of the present invention is to provide a four-pipe air-conditioning system with stepless adjustable heating capacity, which can realize stepless adjustment of the heating output capacity of the four-pipe unit, avoid the unit switching working mode, which causes fluctuations in cold and hot water temperatures, and extend the service life of the four-pipe unit.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A four-pipe air conditioning system with stepless adjustable heating capacity comprises a compressor, a hot water heat exchanger, a cold water heat exchanger, a reversing circuit, an air side heat exchanger and a throttling circuit, wherein the reversing circuit comprises a four-way reversing valve and a three-way valve, the E port of the four-way reversing valve is connected to the B1 port of the three-way valve, the outlet end of the compressor is connected to the D port of the four-way reversing valve, the S port of the four-way reversing valve is connected to the inlet end of a gas-liquid separator, the outlet end of the gas-liquid separator is connected to the inlet end of the compressor, the C port of the four-way reversing valve is connected to one end of the air side heat exchanger, the other end of the air side heat exchanger is connected to the B2 port of the three-way valve and the throttling circuit, the A port of the three-way valve is connected to one end of the hot water heat exchanger, the other end of the hot water heat exchanger is connected to the throttling circuit, the throttling circuit is connected to one end of the cold water heat exchanger, and the other end of the cold water heat exchanger is connected to the inlet end of the gas-liquid separator;

[0007] The air-side heat exchanger includes a finned heat exchanger and a wind power component that assists the finned heat exchanger in heat exchange;

[0008] The throttling circuit includes an expansion valve I, an expansion valve II, a liquid reservoir and a filter, one end of the liquid reservoir is connected to the hot water heat exchanger, the other end of the liquid reservoir is connected to one end of the filter, the other end of the filter is connected to one end of the expansion valve I and the expansion valve II, and the other end of the expansion valve II is connected to the cold water heat exchanger;

[0009] The C port of the four-way reversing valve is connected to one end of the finned heat exchanger, and the other end of the finned heat exchanger is connected to the B2 port of the three-way valve and the other end of the expansion valve I;

[0010] The four-way reversing valve and the three-way valve switch the refrigerant flow process compressed and output by the compressor, providing a cold / hot water combined supply full power heating mode, a cold / hot water combined supply heating stepless adjustment mode, a cold water supply only mode, a hot water supply only mode and a defrost mode;

[0011] In the cold / hot water combined supply full-power heating mode: the D port of the four-way reversing valve is connected to the E port, the C port of the four-way reversing valve is connected to the S port; the A port of the three-way valve is connected to the B1 port, and the refrigerant is compressed into high-temperature and high-pressure gas by the compressor and flows through the four-way reversing valve and the three-way valve in sequence before entering the hot water heat exchanger, where it is cooled into low-temperature and high-pressure liquid, and then flows through the liquid storage device and the filter in sequence, and then enters the cold water heat exchanger to evaporate after being throttled by the expansion valve II, and then flows through the gas-liquid separator before entering the compressor, completing the vapor compression cycle of the refrigerant;

[0012] In the stepless regulation mode of combined cold / hot water heating: the D port of the four-way reversing valve is connected to the C port, the E port of the four-way reversing valve is connected to the S port; the A port of the three-way valve is connected to the B2 port, and the refrigerant is compressed into a high-temperature and high-pressure gas by the compressor and then flows through the four-way reversing valve to enter the finned heat exchanger, and the refrigerant is partially cooled and dissipated in the finned heat exchanger. After flowing out of the coil, the partially cooled refrigerant first enters the three-way valve and then enters the hot water heat exchanger. The refrigerant is completely cooled in the hot water heat exchanger to become a low-temperature and high-pressure liquid, and then flows through the liquid storage tank and the filter in sequence, and enters the cold water heat exchanger after throttling by the expansion valve II to evaporate, and then flows through the gas-liquid separator and enters the compressor to complete the vapor compression cycle of the refrigerant;

[0013] In the cold water supply only mode: the D port of the four-way reversing valve is connected to the C port, the E port of the four-way reversing valve is connected to the S port; the A port of the three-way valve is connected to the B2 port, and the refrigerant is compressed by the compressor into a high-temperature and high-pressure gas, and then flows through the four-way reversing valve and enters the finned heat exchanger. The refrigerant is completely cooled in the finned heat exchanger and becomes a low-temperature and high-pressure liquid, and then flows through the three-way valve, the hot water heat exchanger, the liquid storage and the filter in sequence, and then enters the cold water heat exchanger after throttling by the expansion valve II to evaporate, and then flows through the gas-liquid separator and enters the compressor, completing the vapor compression cycle of the refrigerant;

[0014] In the hot water supply only mode: the D port of the four-way reversing valve is connected to the E port, the C port of the four-way reversing valve is connected to the S port; the A port of the three-way valve is connected to the B1 port, and the refrigerant is compressed into a high-temperature and high-pressure gas by the compressor, and then flows through the four-way reversing valve and the three-way valve into the hot water heat exchanger, and the refrigerant is completely cooled in the hot water heat exchanger to become a low-temperature and high-pressure liquid, and then flows through the liquid storage tank and the filter in sequence, and enters the finned heat exchanger after throttling by the expansion valve I to evaporate, and then flows through the gas-liquid separator and enters the compressor, completing the vapor compression cycle of the refrigerant;

[0015] In the defrost mode: the D port of the four-way reversing valve is connected to the C port, the E port of the four-way reversing valve is connected to the S port; the A port of the three-way valve is connected to the B1 port, and the refrigerant is compressed into high-temperature and high-pressure gas by the compressor and then flows through the fin heat exchanger, and the frost layer on the surface of the fin is melted by the high-temperature refrigerant. The refrigerant is then throttled by the expansion valve I, and then flows through the filter and the liquid storage tank. The refrigerant absorbs heat in the hot water heat exchanger and becomes gas, and then enters the three-way valve and the gas-liquid separator and then enters the compressor, completing the vapor compression cycle of the refrigerant.

[0016] The beneficial effects of the present invention are:

[0017] The present invention has multiple modes, and provides a cold / hot water combined supply full power heating mode, a cold / hot water combined supply stepless adjustment mode, a cold water only mode, a hot water only mode and a defrosting mode by switching the refrigerant flow through the compressor compressed output by a four-way reversing valve and a three-way valve; in the cold / hot water combined supply stepless adjustment mode, by detecting the difference between the heat production of the unit and the heat demand of the user, when the heating capacity of the unit is greater than the user demand value, the speed of the axial flow fan can be increased to increase the condensation heat discharged into the air by the finned heat exchanger, thereby reducing the condensation heat absorbed by the hot water heat exchanger and reducing the heating capacity of the unit; similarly, when the heating capacity of the unit is less than the user's heat demand, the speed of the axial flow fan can be reduced to reduce the condensation heat discharged by the finned heat exchanger, thereby increasing the condensation heat absorbed by the hot water heat exchanger and increasing the heating capacity of the unit;

[0018] Stepless regulation can ensure that the unit can operate in the same mode for a long time. The unit mode will not be frequently switched due to the difference between the unit's cooling / heating capacity and the user's cooling / heating demand or the frequent changes in the user's cooling / heating demand, thus avoiding fluctuations in the temperature of cold water and hot water and affecting the user's experience. At the same time, it also reduces the number of starts, stops, and switches of components such as the compressor and four-way reversing valve, thereby extending the service life of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0020] Figure 1 It is a working logic diagram of a four-pipe air conditioning system with stepless adjustable heating capacity according to the present invention;

[0021] Figure 2 It is a logic diagram of the cold / hot water combined supply full power heating mode of the air conditioning system of the present invention;

[0022] Figure 3 It is a logic diagram of the stepless regulation mode of cold / hot water combined heating and supply of the air-conditioning system of the present invention;

[0023] Figure 4 is a logic diagram of the cold water supply only mode of the air conditioning system of the present invention;

[0024] Figure 5 is a logic diagram of the air conditioning system of the present invention in hot water supply only mode;

[0025] Figure 6 is a logical schematic diagram of the defrost mode of the air conditioning system of the present invention;

[0026] Figure 7 is a schematic diagram of a wind power component of the present invention;

[0027] Figure 8 is a schematic cross-sectional view of a wind power component of the present invention;

[0028] Fig. 9 is a schematic diagram of an axial flow fan of the present invention;

[0029] Fig.10 It is a schematic diagram of a partial enlarged view of A of the present invention.

[0030] In the figure: compressor 1; four-way reversing valve 2; three-way valve 3; wind force component 4; wind gathering sleeve 41; cooling cavity 42; expansion sleeve 43; cooling water pipeline 44; mounting plate 45; axial flow fan 46; finned heat exchanger 5; expansion valve I 6; expansion valve II 7; hot water heat exchanger 8; cold water heat exchanger 9; liquid storage tank 10; gas-liquid separator 11; filter 12; reversing circuit 101; air side heat exchanger 102; throttling circuit 103. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below with reference to the accompanying drawings.

[0032] It should be noted that the working modes of the four-pipe unit mentioned in this application, such as separate hot water supply, separate cold water supply, and cold / hot water combined supply, are relatively common terms in the industry and are widely accepted by people, but so far there are no corresponding national standards or industry standards to clearly define them.

[0033] It should be noted that the "high temperature", "medium temperature", "low temperature", "high pressure", "low pressure", "throttling" and other terms mentioned in this temperature are relative concepts, not commonly known concepts in the industry, and do not have specific numerical ranges; for example, if the refrigerant state of the previous node is described as high temperature and the refrigerant state of the next node is described as medium temperature, it means that the refrigerant has partially dissipated heat; if the refrigerant state of the next node is described as low temperature, it means that the refrigerant has completely dissipated heat;

[0034] like Figures 1 to 6 As shown, in order to achieve the technical effect of "being able to steplessly adjust the heating output capacity of the four-pipe unit, avoiding the unit's working mode switching, resulting in fluctuations in the temperature of cold and hot water, and extending the service life of the four-pipe unit", the structure and function of a four-pipe air-conditioning system with stepless heating capacity adjustment are described in detail below;

[0035] like Figure 1 As shown, a four-pipe air conditioning system with stepless heating capacity adjustment includes a compressor 1, a hot water heat exchanger 8, a cold water heat exchanger 9, a reversing circuit 101, an air side heat exchanger 102 and a throttling circuit 103, wherein the reversing circuit 101 includes a four-way reversing valve 2 and a three-way valve 3, wherein the E port of the four-way reversing valve 2 is connected to the B1 port of the three-way valve 3, the outlet end of the compressor 1 is connected to the D port of the four-way reversing valve 2, the S port of the four-way reversing valve 2 is connected to the inlet end of the gas-liquid separator 11, and the gas-liquid separator 11 is connected to the gas-liquid separator 11. The outlet end of the separator 11 is connected to the inlet end of the compressor 1, the C port of the four-way reversing valve 2 is connected to one end of the air side heat exchanger 102, the other end of the air side heat exchanger 102 is connected to the B2 port of the three-way valve 3 and the throttling circuit 103, the A of the three-way valve 3 is connected to one end of the hot water heat exchanger 8, the other end of the hot water heat exchanger 8 is connected to the throttling circuit 103, the throttling circuit 103 is connected to one end of the cold water heat exchanger 9, and the other end of the cold water heat exchanger 9 is connected to the inlet end of the gas-liquid separator 11;

[0036] The air-side heat exchanger 102 includes a finned heat exchanger 5 and a wind force component 4 that assists the finned heat exchanger 5 in heat exchange; the heat dissipation of the finned heat exchanger 5 is determined according to the heat demand of the user side, and the heat dissipation of the finned heat exchanger 5 is adjusted by adjusting the wind force component 4;

[0037] The structure of the wind force component 4 is as follows Figures 7 to 9 As shown, the wind force component 4 includes a wind gathering sleeve 41, a cooling cavity 42, an expansion sleeve 43, a cooling water pipe 44, a mounting plate 45 and an axial flow fan 46. The front end of the wind gathering sleeve 41 is fixedly connected with a plurality of cooling cavities 42 arranged side by side, and the rear end of the wind gathering sleeve 41 is fixedly connected with the mounting plate 45. The wind gathering sleeve 41 is conically arranged, and the end of the wind gathering sleeve 41 with a small diameter is the front end, and the end of the wind gathering sleeve 41 with a large diameter is the rear end. The cooling cavity 42 is fixedly connected with a cooling water pipe 44, the cooling cavity 42 is fixedly connected with an expansion sleeve 43, and the mounting plate 45 is provided with a plurality of axial flow fans 46;

[0038] When the wind force generated by the wind force component 4 needs to be adjusted, the axial flow fans 46 are started. According to different usage requirements, different numbers of axial flow fans 46 are started. The axial flow fans 46 generate a certain wind force. The wind force generated by the axial flow fans 46 is gathered by the wind gathering sleeve 41 and then discharged through the inner side of the multiple expansion sleeves 43 to blow toward the fin heat exchanger 5.

[0039] Furthermore, when the temperature of the gas blown out of the wind force component 4 can be adjusted, cooling water is introduced into the cooling water pipe 44 and then into the expansion sleeve 43. The pressure in the expansion sleeve 43 increases, and the expansion sleeve 43 expands. Figure 8 As shown, the thickness of the middle part of the expansion sleeve 43 is thinner than the thickness of the two sides of the expansion sleeve 43, so the middle part of the expansion sleeve 43 expands first, that is, the expansion sleeve 43 expands inward, and the wind is blown out after the temperature is reduced by the expansion sleeve 43. At the same time, the area of ​​wind spraying is controlled by the expansion of the expansion sleeve 43. The temperature and area of ​​wind blowing can be controlled by multiple expansion sleeves 43 to meet different heat exchange requirements;

[0040] The throttling circuit 103 includes an expansion valve I6, an expansion valve II7, a liquid reservoir 10 and a filter 12. One end of the liquid reservoir 10 is connected to the hot water heat exchanger 8, the other end of the liquid reservoir 10 is connected to one end of the filter 12, the other end of the filter 12 is connected to one end of the expansion valve I6 and the expansion valve II7, and the other end of the expansion valve II7 is connected to the cold water heat exchanger 9.

[0041] The C port of the four-way reversing valve 2 is connected to one end of the finned heat exchanger 5, and the other end of the finned heat exchanger 5 is connected to the B2 port of the three-way valve 3 and the other end of the expansion valve I6;

[0042] The four-way reversing valve 2 and the three-way valve 3 switch the refrigerant compressed and output by the compressor 1 through the flow process, providing a cold / hot water combined supply full power heating mode, a cold / hot water combined supply heating stepless adjustment mode, a cold water only supply mode, a hot water only supply mode and a defrost mode;

[0043] like Figure 2As shown, the red one is the refrigerant circulation line. In the cold / hot water combined supply full power heating mode: the D port of the four-way reversing valve 2 is connected to the E port, and the C port of the four-way reversing valve 2 is connected to the S port; the A port of the three-way valve 3 is connected to the B1 port. After being compressed into high-temperature and high-pressure gas by the compressor 1, the refrigerant flows through the four-way reversing valve 2 and the three-way valve 3 in sequence and then enters the hot water heat exchanger 8. In the hot water heat exchanger 8, it is cooled into low-temperature and high-pressure liquid, and then flows through the liquid storage tank 10 and the filter 12 in sequence. After being throttled by the expansion valve II 7, it enters the cold water heat exchanger 9 to evaporate, and then flows through the gas-liquid separator 11 and enters the compressor 1, completing the vapor compression cycle of the refrigerant.

[0044] In the full-power heating mode of cold / hot water combined supply: the circulation process of the refrigerant is: compressor 1→four-way reversing valve 2→three-way valve 3→hot water heat exchanger 8→liquid storage tank 10→filter 12→expansion valve II 7→cold water heat exchanger 9→gas-liquid separator 11→compressor 1;

[0045] like Figure 3 As shown, the red one is the refrigerant circulation line. In the stepless regulation mode of combined cold / hot water heating supply: the D port of the four-way reversing valve 2 is connected to the C port, and the E port of the four-way reversing valve 2 is connected to the S port; the A port of the three-way valve 3 is connected to the B2 port. After the refrigerant is compressed into high-temperature and high-pressure gas by the compressor 1, it flows through the four-way reversing valve 2 and enters the finned heat exchanger 5. The refrigerant is partially cooled and dissipated in the finned heat exchanger 5. After flowing out of the coil, the partially cooled refrigerant first enters the three-way valve 3 and then enters the hot water heat exchanger 8. The refrigerant is completely cooled in the hot water heat exchanger 8 and becomes a low-temperature and high-pressure liquid. Then, it flows through the liquid storage tank 10 and the filter 12 in sequence, enters the cold water heat exchanger 9 after being throttled by the expansion valve II 7 to evaporate, and then flows through the gas-liquid separator 11 and enters the compressor 1 to complete the vapor compression cycle of the refrigerant.

[0046] In the stepless regulation mode of combined cold / hot water heating: the circulation process of the refrigerant is: compressor 1→four-way reversing valve 2→finned heat exchanger 5→three-way valve 3→hot water heat exchanger 8→liquid storage tank 10→filter 12→expansion valve II 7→cold water heat exchanger 9→gas-liquid separator 11→compressor 1;

[0047] like Figure 4As shown, the red one is the refrigerant circulation line, in the cold water mode only: the D port of the four-way reversing valve 2 is connected to the C port, the E port of the four-way reversing valve 2 is connected to the S port; the A port of the three-way valve 3 is connected to the B2 port, and the refrigerant is compressed into a high-temperature and high-pressure gas by the compressor 1, and then flows through the four-way reversing valve 2 and enters the finned heat exchanger 5. The refrigerant is completely cooled in the finned heat exchanger 5 and becomes a low-temperature and high-pressure liquid, and then flows through the three-way valve 3, the hot water heat exchanger 8, the liquid storage tank 10 and the filter 12 in sequence, and then enters the cold water heat exchanger 9 after throttling by the expansion valve II 7 to evaporate, and then flows through the gas-liquid separator 11 and enters the compressor 1, completing the vapor compression cycle of the refrigerant;

[0048] In the cold water supply mode only: the refrigerant circulation process is: compressor 1→four-way reversing valve 2→finned heat exchanger 5→three-way valve 3→hot water heat exchanger 8→liquid storage tank 10→filter 12→expansion valve II 7→cold water heat exchanger 9→gas-liquid separator 11→compressor 1;

[0049] like Figure 5 As shown, the red one is the refrigerant circulation line. In the hot water supply only mode: the D port of the four-way reversing valve 2 is connected to the E port, the C port of the four-way reversing valve 2 is connected to the S port; the A port of the three-way valve 3 is connected to the B1 port. After the refrigerant is compressed into a high-temperature and high-pressure gas by the compressor 1, it flows through the four-way reversing valve 2 and the three-way valve 3 and enters the hot water heat exchanger 8. The refrigerant is completely cooled in the hot water heat exchanger 8 and becomes a low-temperature and high-pressure liquid. Then, it flows through the liquid storage tank 10 and the filter 12 in sequence, and enters the finned heat exchanger 5 after throttling by the expansion valve I6 to evaporate. Then, it flows through the gas-liquid separator 11 and enters the compressor 1 to complete the vapor compression cycle of the refrigerant.

[0050] In hot water supply mode only: the refrigerant circulation process is: compressor 1→four-way reversing valve 2→three-way valve 3→hot water heat exchanger 8→liquid storage tank 10→filter 12→expansion valve I6→finned heat exchanger 5→four-way reversing valve 2→gas-liquid separator 11→compressor 1;

[0051] like Figure 6 As shown, the red one is the refrigerant flow line. In the defrosting mode: the D port of the four-way reversing valve 2 is connected to the C port, the E port of the four-way reversing valve 2 is connected to the S port; the A port of the three-way valve 3 is connected to the B1 port. After the refrigerant is compressed into high-temperature and high-pressure gas by the compressor 1, it flows through the fin heat exchanger 5, and the frost layer on the surface of the fin is melted by the high-temperature refrigerant. The refrigerant is then throttled by the expansion valve I6, and then flows through the filter 12 and the liquid storage tank 10. The refrigerant absorbs heat in the hot water heat exchanger 8 and becomes gas, and then enters the three-way valve 3 and the gas-liquid separator 11 and then enters the compressor 1, completing the vapor compression cycle of the refrigerant.

[0052] In defrost mode: the circulation process of the refrigerant is: compressor 1→four-way reversing valve 2→finned heat exchanger 5→expansion valve II 7→filter 12→liquid receiver 10→hot water heat exchanger 8→three-way valve 3→gas-liquid separator 11→compressor 1.

Claims

1. A four-pipe air conditioning system with steplessly adjustable heating capacity, comprising a compressor (1), a hot water heat exchanger (8), a cold water heat exchanger (9), a reversing circuit (101), an air-side heat exchanger (102) and a throttling circuit (103), characterized in that: The reversing circuit (101) comprises a four-way reversing valve (2) and a three-way valve (3); the E port of the four-way reversing valve (2) is connected to the B1 port of the three-way valve (3); the outlet end of the compressor (1) is connected to the D port of the four-way reversing valve (2); the S port of the four-way reversing valve (2) is connected to the inlet end of the gas-liquid separator (11); the outlet end of the gas-liquid separator (11) is connected to the inlet end of the compressor (1); the C port of the four-way reversing valve (2) is connected to the air side heat exchanger. The air side heat exchanger (102) is connected to one end of the air side heat exchanger (102), the other end of the air side heat exchanger (102) is connected to the B2 port of the three-way valve (3) and the throttling circuit (103), the A of the three-way valve (3) is connected to one end of the hot water heat exchanger (8), the other end of the hot water heat exchanger (8) is connected to the throttling circuit (103), the throttling circuit (103) is connected to one end of the cold water heat exchanger (9), and the other end of the cold water heat exchanger (9) is connected to the inlet end of the gas-liquid separator (11); The air-side heat exchanger (102) comprises a finned heat exchanger (5) and a wind power component (4) that assists the finned heat exchanger (5) in heat exchange; The throttling circuit (103) comprises an expansion valve I (6), an expansion valve II (7), a liquid reservoir (10) and a filter (12); one end of the liquid reservoir (10) is connected to a hot water heat exchanger (8); the other end of the liquid reservoir (10) is connected to one end of the filter (12); the other end of the filter (12) is connected to one end of the expansion valve I (6) and the expansion valve II (7); and the other end of the expansion valve II (7) is connected to a cold water heat exchanger (9); The C port of the four-way reversing valve (2) is connected to one end of the finned heat exchanger (5), and the other end of the finned heat exchanger (5) is connected to the B2 port of the three-way valve (3) and the other end of the expansion valve I (6); The four-way reversing valve (2) and the three-way valve (3) switch the refrigerant compressed and output by the compressor (1) through a flow process, providing a cold / hot water combined supply full-power heating mode, a cold / hot water combined supply heating stepless adjustment mode, a cold water supply only mode, a hot water supply only mode and a defrosting mode.

2. A four-pipe air conditioning system with stepless adjustable heating capacity according to claim 1, characterized in that: In the cold / hot water combined supply full-power heating mode: the D port of the four-way reversing valve (2) is connected to the E port, the C port of the four-way reversing valve (2) is connected to the S port; the A port of the three-way valve (3) is connected to the B1 port, and the refrigerant is compressed into high-temperature and high-pressure gas by the compressor (1), and then flows through the four-way reversing valve (2) and the three-way valve (3) in sequence before entering the hot water heat exchanger (8), where it is cooled into low-temperature and high-pressure liquid, and then flows through the liquid storage device (10) and the filter (12) in sequence, and then enters the cold water heat exchanger (9) for evaporation after being throttled by the expansion valve II (7), and then flows through the gas-liquid separator (11) before entering the compressor (1), thereby completing the vapor compression cycle of the refrigerant.

3. A four-pipe air conditioning system with stepless adjustable heating capacity according to claim 1, characterized in that: In the stepless regulation mode of combined cold / hot water heating supply: the D port of the four-way reversing valve (2) is connected to the C port, the E port of the four-way reversing valve (2) is connected to the S port; the A port of the three-way valve (3) is connected to the B2 port, and the refrigerant is compressed by the compressor (1) into a high-temperature and high-pressure gas and then flows through the four-way reversing valve (2) and enters the finned heat exchanger (5). The refrigerant is partially cooled and dissipated in the finned heat exchanger (5). After flowing out of the coil, the partially cooled refrigerant first enters the three-way valve (3) and then enters the hot water heat exchanger (8). The refrigerant is completely cooled in the hot water heat exchanger (8) and becomes a low-temperature and high-pressure liquid. The refrigerant then flows through the liquid storage tank (10) and the filter (12) in sequence, enters the cold water heat exchanger (9) for evaporation after being throttled by the expansion valve II (7), and then flows through the gas-liquid separator (11) and enters the compressor (1), completing the vapor compression cycle of the refrigerant.

4. A four-pipe air conditioning system with stepless adjustable heating capacity according to claim 1, characterized in that: In the cold water supply only mode: the D port of the four-way reversing valve (2) is connected to the C port, the E port of the four-way reversing valve (2) is connected to the S port; the A port of the three-way valve (3) is connected to the B2 port, and the refrigerant is compressed by the compressor (1) into a high-temperature and high-pressure gas, and then flows through the four-way reversing valve (2) and enters the finned heat exchanger (5). The refrigerant is completely cooled in the finned heat exchanger (5) to become a low-temperature and high-pressure liquid, and then flows through the three-way valve (3), the hot water heat exchanger (8), the liquid storage tank (10) and the filter (12) in sequence, and then enters the cold water heat exchanger (9) for evaporation after being throttled by the expansion valve II (7), and then flows through the gas-liquid separator (11) and enters the compressor (1), completing the vapor compression cycle of the refrigerant.

5. A four-pipe air conditioning system with stepless adjustable heating capacity according to claim 1, characterized in that: In the hot water supply only mode: the D port of the four-way reversing valve (2) is connected to the E port, the C port of the four-way reversing valve (2) is connected to the S port; the A port of the three-way valve (3) is connected to the B1 port, and the refrigerant is compressed by the compressor (1) into a high-temperature and high-pressure gas, and then flows through the four-way reversing valve (2) and the three-way valve (3) and enters the hot water heat exchanger (8). The refrigerant is completely cooled in the hot water heat exchanger (8) to become a low-temperature and high-pressure liquid, and then flows through the liquid storage tank (10) and the filter (12) in sequence, and then enters the finned heat exchanger (5) for evaporation after being throttled by the expansion valve I (6), and then flows through the gas-liquid separator (11) and enters the compressor (1), completing the vapor compression cycle of the refrigerant.

6. A four-pipe air conditioning system with stepless adjustable heating capacity according to claim 1, characterized in that: In the defrosting mode, the D port of the four-way reversing valve (2) is connected to the C port, the E port of the four-way reversing valve (2) is connected to the S port; the A port of the three-way valve (3) is connected to the B1 port, and the refrigerant is compressed into high-temperature and high-pressure gas by the compressor (1) and then flows through the finned heat exchanger (5), where the frost layer on the surface of the fin is melted by the high-temperature refrigerant. The refrigerant is then throttled by the expansion valve I (6), and then flows through the filter (12) and the liquid storage tank (10). The refrigerant absorbs heat in the hot water heat exchanger (8) and becomes gas, and then enters the three-way valve (3) and the gas-liquid separator (11) and then enters the compressor (1), completing the vapor compression cycle of the refrigerant.

Images