Four-pipe air conditioning unit

Abstract

The utility model discloses a four -way control air conditioning unit, it includes: through the refrigerant pipeline network connection together's compressor, four -way valve heating side heat exchanger, refrigeration side heat exchanger and outside heat exchanger, four -way valve is used for controlling the flow of refrigerant to select the working mode of air conditioning unit, and the working mode includes any one in cold -heat combined mode, single refrigeration mode, single heating mode, pressure balance device, it includes at least one bypass pipeline and the control valve of setting on bypass pipeline, bypass pipeline intercommunication compressor's high -pressure side and low -pressure side are used for when four -way valve transforms state to switch the working mode, through the opening and closing of control valve, the refrigerant of high -pressure side is guided to low -pressure side to reduce high -pressure side and low -pressure side's pressure difference. The above -mentioned four -way control air conditioning unit, through the configuration of pressure balance device, avoided the defect that needs complete shutdown and waits for pressure natural balance in the prior art, to realize quick mode switching, protect four -way valve to be impacted by pressure simultaneously.

Description

Technical Field

[0001] This utility model relates to the field of air conditioning technology, and in particular to a four-pipe air conditioning unit. Background Technology

[0002] Four-pipe air conditioning units, as a highly efficient air conditioning system, are widely used in scenarios that require simultaneous cooling and heating. When operating in combined cooling and heating mode, they can dehumidify using chilled water and simultaneously recover heat to produce hot water for temperature regulation, thereby achieving constant temperature and humidity control.

[0003] However, in actual operation, the unit's operating mode needs to switch between combined cooling and heating mode, cooling-only mode, and heating-only mode according to specific needs. For example, when operating in combined cooling and heating mode, if the heating side water temperature has reached the set hot water temperature for temperature adjustment, but the cooling side water temperature has not yet reached the set cold water temperature for dehumidification, then there is no need to continue heating the hot water side water temperature, and the unit needs to switch to cooling-only mode to meet the cooling demand.

[0004] In existing technologies, four-pipe air conditioning units typically switch modes by controlling the refrigerant flow through a four-way valve. However, due to the significant pressure difference between the high-pressure and low-pressure sides of the system during mode switching, directly switching the four-way valve can cause substantial mechanical shock, potentially leading to deformation or even damage to the valve's internal slider or end caps. To avoid this problem, the industry-standard solution is to first shut down the unit to balance the high and low pressure differences when mode switching is required. Once the pressure is balanced, the unit is restarted, and the four-way valve is switched during the establishment of the new pressure difference to complete the mode transition.

[0005] However, this shutdown-balancing-restart operation method has significant drawbacks. Taking the switching from combined cooling and heating mode to cooling-only mode as an example, when the heating-side water temperature meets the requirements but the cooling-side water temperature still needs to be lowered, the unit must shut down to switch modes. To protect the compressor and prevent pressurized start-up, it is usually necessary to wait about three minutes for pressure balancing before restarting. Furthermore, both the shutdown and startup processes require a control reset procedure, resulting in a time interval of 5 to 8 minutes from shutdown to restart and restoration of normal output capacity. During this period, due to the interruption of cooling output, the cooling-side water temperature continues to rise, leading to inaccurate indoor temperature and humidity control and making control difficult. This not only causes discomfort for users but also makes it difficult to meet the requirements for precise temperature and humidity control in industrial applications. Utility Model Content

[0006] The purpose of this invention is to provide a four-pipe air conditioning unit that can switch operating modes without shutting down the system and without damaging the four-way valve, in order to overcome the shortcomings of the above-mentioned technical problems.

[0007] To achieve the above objectives, this utility model provides a four-pipe air conditioning unit, comprising: The unit comprises a compressor, a four-way valve, a heating-side heat exchanger, a cooling-side heat exchanger, and an external heat exchanger, all connected by a refrigerant piping network. The refrigerant piping network provides a path for the refrigerant's circulation. The heating-side heat exchanger transfers heat from the refrigerant to a first medium, the cooling-side heat exchanger transfers cold energy from the refrigerant to a second medium, and the external heat exchanger exchanges heat between the refrigerant and outside air. The four-way valve controls the refrigerant flow direction to select the operating mode of the air conditioning unit, which may include any one of a combined cooling and heating mode, a cooling-only mode, or a heating-only mode. A pressure balancing device includes at least one bypass pipe and a control valve disposed on the bypass pipe; the bypass pipe connects the high-pressure side and the low-pressure side of the compressor, and is used to guide the refrigerant on the high-pressure side to the low-pressure side by opening and closing the control valve when the four-way valve changes state to switch the operating mode, so as to reduce the pressure difference between the high-pressure side and the low-pressure side.

[0008] Preferably, it also includes a pressure detection device for detecting the pressure difference between the high-pressure side and the low-pressure side; When the pressure detection device detects that the pressure difference is less than a preset threshold, the four-way valve performs the operation of switching the working mode, and at the same time the control valve closes.

[0009] Preferably, the pressure detection device includes a high-pressure sensor disposed at the output end of the compressor and a low-pressure sensor disposed at the recovery end of the compressor. The high-pressure sensor is used to detect the refrigerant pressure value on the high-pressure side, and the low-pressure sensor is used to detect the pressure value on the low-pressure side.

[0010] Preferably, the bypass pipeline includes a first bypass pipe and a second bypass pipe, one end of the first bypass pipe and one end of the second bypass pipe are both connected between the output end of the compressor and the inlet of the four-way valve, the other end of the first bypass pipe is connected to the pipeline between the four-way valve and the heating-side heat exchanger, and the other end of the second bypass pipe is connected to the pipeline between the four-way valve and the outer heat exchanger; the control valve includes a first valve and a second valve respectively disposed on the first bypass pipe and the second bypass pipe.

[0011] Preferably, both the first valve and the second valve are solenoid valves.

[0012] Preferably, the outer heat exchanger is a finned heat exchanger.

[0013] Preferably, both the first medium and the second medium are water.

[0014] Preferably, it also includes an economizer installed in the refrigerant piping network, the economizer being located on the pipeline between the heating-side heat exchanger and the cooling-side heat exchanger, for recovering a portion of the cooling or heating energy through secondary heat exchange of the refrigerant.

[0015] Compared to existing technologies, the four-pipe air conditioning unit provided by the above-mentioned technical solution does not require shutdown when switching operating modes. The pressure balancing device actively guides the refrigerant from the high-pressure side to the low-pressure side through a bypass pipe and control valve, achieving a rapid reduction in pressure difference. Once the pressure difference meets the requirements, the four-way valve performs the switching operation. This avoids the process of stopping and waiting for pressure balancing, thereby shortening the total time for mode switching to a few seconds. This significantly improves the continuity of air conditioning unit operation, ensuring that the air conditioning unit can quickly respond to changes in demand in industrial or commercial environments, improving temperature and humidity control accuracy, and enhancing the user experience. Moreover, due to the reduction in pressure difference, mechanical shock is significantly reduced. This not only protects core components such as the four-way valve and compressor but also reduces maintenance frequency and replacement costs, improving the overall system's durability and reliability. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the four-pipe air conditioning unit in this embodiment of the present invention.

[0017] Figure 2 This is a diagram showing the refrigerant flow of a four-pipe air conditioning unit in the combined cooling and heating mode according to an embodiment of this utility model.

[0018] Figure 3 This is a diagram showing the refrigerant flow of a four-pipe air conditioning unit in single-cooling mode according to an embodiment of this utility model.

[0019] Figure 4 This is a diagram showing the refrigerant flow of a four-pipe air conditioning unit in single heating mode according to an embodiment of this utility model. Detailed Implementation

[0020] To explain in detail the technical content, structural features, objectives and effects of this utility model, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0021] This embodiment discloses a four-pipe air conditioning unit that can switch operating modes without shutting down and without causing pressure shock to related core components.

[0022] like Figure 1 The air conditioning unit includes a compressor M, a four-way valve FV, a heating-side heat exchanger HE1, a cooling-side heat exchanger HE2, and an outer heat exchanger HE3, all connected together via a refrigerant piping network.

[0023] The refrigerant piping network provides a path for the circulation of refrigerant. The heating-side heat exchanger HE1 is used to transfer the heat energy in the refrigerant to the first medium, the cooling-side heat exchanger HE2 is used to transfer the cold energy in the refrigerant to the second medium, and the outer heat exchanger HE3 is used to exchange heat between the refrigerant and the outside air.

[0024] In addition, an economizer HE4 is installed in the refrigerant piping network. The economizer HE4 is located on the pipeline between the heating-side heat exchanger HE1 and the cooling-side heat exchanger HE2. It is used to recover part of the cooling or heating energy through secondary heat exchange of the refrigerant, so as to improve the operating efficiency of the air conditioning unit in the combined cooling and heating mode.

[0025] The four-way valve (FV) is used to control the flow of refrigerant to select the operating mode of the air conditioning unit. The operating modes include any one of the following: combined cooling and heating mode, cooling-only mode, and heating-only mode.

[0026] In this embodiment, both the first and second media are water, but this is not a limitation. Therefore, the cooling-side heat exchanger HE2 is used to produce chilled water, and the heating-side heat exchanger HE1 is used to produce hot water. The outer heat exchanger HE3 is a finned heat exchanger.

[0027] When the four-way valve FV is switched, the refrigerant flow direction changes, and the pressure distribution on the high-pressure and low-pressure sides will change. If the switch is performed directly, it may cause the four-way valve FV or the compressor M to malfunction.

[0028] Therefore, this embodiment provides a solution for temporarily balancing the high and low pressure differences between the high-pressure side and the low-pressure side. That is, the air conditioning unit also includes a pressure balancing device, which includes at least one bypass pipe and a control valve installed on the bypass pipe.

[0029] The bypass pipe connects the high-pressure side and the low-pressure side of compressor M. When the four-way valve FV changes state to switch the working mode, it guides the refrigerant on the high-pressure side to the low-pressure side by controlling the opening and closing of the valve, so as to reduce the pressure difference between the high-pressure side and the low-pressure side.

[0030] For the aforementioned air conditioning units, when the system needs to switch operating modes (such as switching from combined cooling and heating mode to cooling-only mode), before the four-way valve FV changes state, the control valve opens first, allowing some of the high-pressure refrigerant on the high-pressure side to flow to the low-pressure side through the bypass pipe. Because the refrigerant pressure on the high-pressure side is higher and the pressure on the low-pressure side is lower, this flow will rapidly reduce the pressure difference between the two sides.

[0031] During the opening of the control valve, the refrigerant on the high-pressure side is guided to the low-pressure side, and the pressures on the high and low-pressure sides gradually tend to balance. By properly controlling the valve's opening time and flow rate, it can be ensured that the pressure difference is reduced to a safe range (i.e., to a degree that will not cause impact on the four-way valve FV). Subsequently, the control valve closes, and the four-way valve FV performs a switching operation, adjusting the refrigerant flow direction to achieve the new mode.

[0032] Therefore, the pressure balancing device actively guides refrigerant flow, avoiding the drawback of existing technologies that require complete shutdown and waiting for natural pressure equalization. Compared to traditional methods, this mechanism can complete pressure adjustment in a short time (possibly only a few seconds), thereby achieving rapid mode switching while protecting core components such as the four-way valve (FV) and compressor (M).

[0033] On the other hand, the air conditioning unit also includes a pressure detection device for detecting the pressure difference between the high-pressure side and the low-pressure side.

[0034] When the pressure detection device detects that the pressure difference is less than the preset threshold, the four-way valve FV performs the operation of switching the working mode and at the same time controls the valve to close.

[0035] Specifically, the pressure detection device includes a high-pressure sensor HS installed at the output end of the compressor M and a low-pressure sensor LS installed at the recovery end of the compressor M. The high-pressure sensor HS is used to detect the refrigerant pressure value on the high-pressure side, and the low-pressure sensor LS is used to detect the pressure value on the low-pressure side.

[0036] The control system calculates the pressure difference between the pressure values ​​detected by the high-pressure sensor HS and the low-pressure sensor LS to obtain the pressure difference, and then determines the closing time of the control valve based on the pressure difference.

[0037] On the other hand, the bypass piping includes a first bypass pipe PT1 and a first bypass pipe PT2. One end of the first bypass pipe PT1 and one end of the first bypass pipe PT2 are connected between the output end of the compressor M and the inlet of the four-way valve FV. The other end of the first bypass pipe PT1 is connected to the pipeline between the four-way valve FV and the heating-side heat exchanger HE1, and the other end of the first bypass pipe PT2 is connected to the pipeline between the four-way valve FV and the outer heat exchanger HE3. The control valves include a first valve SV1 and a second valve SV2 respectively installed on the first bypass pipe PT1 and the first bypass pipe PT2.

[0038] Specifically, both the first valve SV1 and the second valve SV2 are solenoid valves.

[0039] In this embodiment, the pressure difference between the high-pressure side and the low-pressure side of the compressor M is temporarily adjusted by controlling the opening and closing of the first valve SV1 or the second valve SV2 between different mode switching.

[0040] The specific connection structure of the four-pipe air conditioning unit in the above embodiment is as follows: First, it should be noted that the four-way valve FV has four valve ports, namely the first valve port D, the second valve port C, the third valve port S, and the fourth valve port E.

[0041] The output end of compressor M is connected to the first valve port D of four-way valve FV, and the second valve port C of four-way valve FV is connected to the heating-side heat exchanger HE1 through the first pipe G1.

[0042] The heating-side heat exchanger HE1 is connected to the liquid storage tank Y via the second pipe G2. The liquid storage tank Y is connected to the inlet side of the economizer HE4 via the third pipe G3. The outlet side of the economizer HE4 is then connected to the refrigeration-side heat exchanger HE2 via the fourth pipe G4. The refrigeration-side heat exchanger HE2 is then connected to the ninth pipe G9, which is located at the refrigerant recovery end of the compressor M, via the fifth pipe G5.

[0043] In addition, the third valve port S of the four-way valve FV is also connected to the ninth pipe G9 through the sixth pipe G6.

[0044] The fourth valve port E of the four-way valve FV is also connected to the outer heat exchanger HE3 through the seventh pipe G7. The outer heat exchanger HE3 is connected to the fourth pipe G4 located on the outlet side of the economizer HE4 through the tenth pipe G10 branched off from the eighth pipe G8.

[0045] The outer heat exchanger HE3 is connected to the inlet side of the economizer HE4 via the eleventh pipe G11 branched off from the eighth pipe G8.

[0046] The first bypass pipe PT1 is connected to the second pipe G2, and the first bypass pipe PT2 is connected to the seventh pipe G7.

[0047] like Figure 2 When the above-mentioned air conditioning unit operates in combined cooling and heating mode, the refrigerant circulation path is as follows: Compressor M - First valve port D - Second valve port C - First pipe G1 - Heating side heat exchanger HE1 - Second pipe G2 - Third pipe G3 - Economizer HE4 - Fourth pipe G4 - Cooling side water heat exchanger - Fifth pipe G5 - Ninth pipe G9 - Compressor M.

[0048] like Figure 3 When the above-mentioned air conditioning unit operates in heating mode only, the refrigerant circulation path is as follows: Compressor M - First valve port D - Second valve port C - First pipe G1 - Heating side heat exchanger HE1 - Second pipe G2 - Third pipe G3 - Economizer HE4 - Tenth pipe G10 - Eighth pipe G8 - Outer heat exchanger HE3 - Seventh pipe G7 - Fourth valve port E - Third valve port S - Sixth pipe G6 - Ninth pipe G9 - Compressor M. Compressor M - First valve port D - Third valve port S - Sixth pipe G6 - Ninth pipe G9 - Compressor M.

[0049] like Figure 4 When the above-mentioned air conditioning unit operates in single cooling mode, its refrigerant circulation path is as follows: Compressor M - First valve port D - Fourth valve port E - Seventh pipe G7 - Outer heat exchanger HE3 - Eighth pipe G8 - Eleventh pipe G11 - Economizer HE4 - Fourth pipe G4 - Fifth pipe G5 - Ninth pipe G9 - Compressor M.

[0050] So, when the air conditioning unit is operating in combined cooling and heating mode, if the heating side water temperature reaches the set water temperature and no longer needs to output heating, but the cooling side water temperature has not yet met the water temperature requirement, the unit needs to switch to cooling-only mode. At this time, the second valve SV2 is opened to bypass the high-pressure gas to the low-pressure side. When the pressure difference detected by the high-pressure sensor HS and the low-pressure sensor LS is <0.6MPa, the four-way valve FV switches, and then the second solenoid valve is closed, thus completing the switch from combined cooling and heating mode to cooling-only mode without stopping the unit.

[0051] Similarly, when the air conditioning unit is running in single cooling mode, if the water temperature on the heating side drops below the set water temperature and heating output needs to be resumed, the unit needs to switch to combined cooling and heating mode. At this time, the first valve SV1 is opened to bypass high-pressure gas to the low-pressure side. When the pressure difference detected by the high-pressure sensor HS and the low-pressure sensor LS is less than 0.6MPa, the four-way valve FV switches, and then the first valve SV1 is closed, thus completing the switch from single cooling mode to combined cooling and heating mode without stopping the unit.

[0052] Switching between working modes in other situations is similar to the above, and will not be repeated here.

[0053] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent variations made in accordance with the scope of the present utility model application shall still fall within the scope of the present utility model.

Claims

1. A four-pipe air conditioning unit, characterized in that, include: The unit comprises a compressor, a four-way valve, a heating-side heat exchanger, a cooling-side heat exchanger, and an external heat exchanger, all connected by a refrigerant piping network. The refrigerant piping network provides a path for the refrigerant's circulation. The heating-side heat exchanger transfers heat from the refrigerant to a first medium, the cooling-side heat exchanger transfers cold energy from the refrigerant to a second medium, and the external heat exchanger exchanges heat between the refrigerant and outside air. The four-way valve controls the refrigerant flow direction to select the operating mode of the air conditioning unit, which may include any one of a combined cooling and heating mode, a cooling-only mode, or a heating-only mode. A pressure balancing device includes at least one bypass pipe and a control valve disposed on the bypass pipe; the bypass pipe connects the high-pressure side and the low-pressure side of the compressor, and is used to guide the refrigerant on the high-pressure side to the low-pressure side by opening and closing the control valve when the four-way valve changes state to switch the operating mode, so as to reduce the pressure difference between the high-pressure side and the low-pressure side.

2. The four-pipe air conditioning unit according to claim 1, characterized in that, It also includes a pressure detection device for detecting the pressure difference between the high-pressure side and the low-pressure side; When the pressure detection device detects that the pressure difference is less than a preset threshold, the four-way valve performs the operation of switching the working mode, and at the same time the control valve closes.

3. The four-pipe air conditioning unit according to claim 2, characterized in that, The pressure detection device includes a high-pressure sensor disposed at the output end of the compressor and a low-pressure sensor disposed at the recovery end of the compressor. The high-pressure sensor is used to detect the refrigerant pressure value on the high-pressure side, and the low-pressure sensor is used to detect the pressure value on the low-pressure side.

4. The four-pipe air conditioning unit according to claim 1, characterized in that, The bypass pipeline includes a first bypass pipe and a second bypass pipe. One end of the first bypass pipe and one end of the second bypass pipe are both connected between the output end of the compressor and the inlet of the four-way valve. The other end of the first bypass pipe is connected to the pipeline between the four-way valve and the heating-side heat exchanger, and the other end of the second bypass pipe is connected to the pipeline between the four-way valve and the outer heat exchanger. The control valve includes a first valve and a second valve respectively disposed on the first bypass pipe and the second bypass pipe.

5. The four-pipe air conditioning unit according to claim 4, characterized in that, Both the first valve and the second valve are solenoid valves.

6. The four-pipe air conditioning unit according to claim 1, characterized in that, The outer heat exchanger is a finned heat exchanger.

7. The four-pipe air conditioning unit according to claim 1, characterized in that, Both the first medium and the second medium are water.

8. The four-pipe air conditioning unit according to claim 1, characterized in that, It also includes an economizer installed in the refrigerant piping network. The economizer is located on the pipeline between the heating-side heat exchanger and the cooling-side heat exchanger and is used to recover part of the cold or heat through secondary heat exchange of the refrigerant.

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