Four-mode multi-pipe air-cooled heat pump unit

Abstract

According to the technical scheme, an outlet of a compressor is connected with a first heat exchanger and a third heat exchanger through a first electric two-way valve, and the third heat exchanger is connected with an inlet of a liquid storage tank through a second electric two-way valve; one end of the first heat exchanger is connected with the first electric two-way valve through a third electric two-way valve, and the other end of the first heat exchanger is connected with the liquid storage tank through a fourth electric two-way valve. An outlet of the liquid storage tank is connected with a second heat exchanger through a fifth electric two-way valve, and the second heat exchanger is connected with the first electric two-way valve through a first normally-closed electromagnetic valve and connected with an inlet of the liquid storage tank through a second normally-closed electromagnetic valve. And an outlet of the liquid storage tank is connected with a fourth electric two-way valve through a fifth electric two-way valve. The three heat exchangers are matched with the electric two-way valve, the normally-closed electromagnetic valve and the like, the flow direction of a refrigerant is controlled to be adjusted, and the functions of refrigerating, heating, refrigerating total heat recovery, water heating and defrosting of the unit are achieved.

Description

Technical Field

[0001] This utility model belongs to the field of heat pump technology, specifically relating to a four-mode multi-pipe air-cooled heat pump unit. Background Technology

[0002] Air-cooled heat pump units operate based on the principle of compression refrigeration cycle. Using refrigerant as a carrier, they absorb heat from the atmosphere through forced heat exchange via a fan and then transfer it to the space or equipment requiring heating, thus achieving cooling in summer and heating in winter. With technological advancements, the requirements for heat pump units are becoming increasingly stringent. In addition to cooling and heating, they typically need to achieve total heat recovery and hot water production to improve energy efficiency and functional versatility. Existing four-mode, four-pipe air-cooled heat pump unit systems can achieve four modes: cooling, heating, total heat recovery, and hot water production. They often employ a three-heat-exchanger + double four-way valve design. The four-way valves are used to change the refrigerant flow direction to achieve mode switching. However, for systems with multiple finned heat exchangers and large cooling capacity, this system suffers from oil retention in the system loop, leading to poor oil return from the compressor.

[0003] Patent CN 214620163 U discloses a dual four-way valve air-cooled heat pump tri-generation system, including a compressor, a gas-liquid separator, a first four-way valve, a second four-way valve, a hot water side heat exchanger, a water storage tank, an air conditioning side heat exchanger, and a finned heat exchanger. The compressor's inlet is connected to the gas-liquid separator, and the compressor's outlet is connected to the second four-way valve, the gas-liquid separator, and the air conditioning side heat exchanger via the first four-way valve. The second four-way valve is further connected to the gas-liquid separator, the hot water side heat exchanger, and the finned heat exchanger. The hot water side heat exchanger is located far from the gas-liquid separator. One end of the second four-way valve is connected to the air conditioning-side heat exchanger via a first diaphragm check valve and a refrigeration electronic expansion valve, and is also connected to the finned heat exchanger via the same first diaphragm check valve and a heating electronic expansion valve. The water storage tank is connected to the hot water-side heat exchanger, forming a hot water heat exchange cycle; this achieves heating, cooling, and hot water supply. However, due to the large flow rate heat exchange in the hot water-side heat exchanger, air conditioning-side heat exchanger, and finned heat exchanger, oil accumulation in the system loop occurs, leading to poor oil return from the compressor and reduced unit efficiency. Therefore, it is necessary to develop a four-mode multi-pipe air-cooled heat pump unit that can balance the amount of refrigerant in different modes and reduce the risk of oil accumulation. Utility Model Content

[0004] To address existing technical problems, this utility model provides a four-mode multi-pipe air-cooled heat pump unit. Through the cooperation of three heat exchangers, an electric two-way valve, and a normally closed solenoid valve, the refrigerant flow direction is controlled to adjust the unit's functions of cooling, heating, total heat recovery of cooling, hot water production, and defrosting.

[0005] The technical solution of this utility model is: a four-mode multi-pipe air-cooled heat pump unit, including a compressor, a first heat exchanger, a second heat exchanger, a third heat exchanger, a liquid storage tank, a gas-liquid separator, and an oil separator; the outlet of the compressor is connected to the first heat exchanger and the third heat exchanger respectively through a first electric two-way valve, the inlet of the compressor is connected to the gas-liquid separator, and an oil separator is provided between the compressor and the first electric two-way valve;

[0006] The outlet of the third heat exchanger is connected to the inlet of the storage tank via a second electric two-way valve;

[0007] One end of the refrigerant pipe of the first heat exchanger is connected to the first electric two-way valve via the third electric two-way valve, and the other end is connected to the liquid storage tank via the fourth electric two-way valve.

[0008] A check valve is installed at the inlet of the storage tank;

[0009] The outlet of the storage tank is connected to the second heat exchanger via the fifth electric two-way valve. The second heat exchanger is connected to the first electric two-way valve via the first normally closed solenoid valve. The second heat exchanger is connected to the inlet of the storage tank via the second normally closed solenoid valve. The second heat exchanger is connected to the gas-liquid separator via the sixth electric two-way valve. The third electric two-way valve and the second electric two-way valve are connected to the gas-liquid separator via the sixth electric two-way valve.

[0010] The outlet of the storage tank is connected to a fifth electric two-way valve via a dryer filter and an electronic expansion valve, and the fifth electric two-way valve is connected to a fourth electric two-way valve.

[0011] Furthermore, a first ball valve is provided between the liquid storage tank and the drying filter, and a second ball valve is provided between the electronic expansion valve and the fifth electric two-way valve.

[0012] Furthermore, the first heat exchanger is a finned heat exchanger, the second heat exchanger is a dry evaporator, and the third heat exchanger is a shell-and-tube heat recovery heat exchanger.

[0013] Furthermore, a fan is installed on one side of the finned heat exchanger.

[0014] Furthermore, the second normally closed solenoid valve is connected between the check valve and the liquid storage tank.

[0015] Furthermore, the outlet of the liquid storage tank is connected to the liquid injection inlet of the compressor via a third normally closed solenoid valve.

[0016] The beneficial effects achieved by adopting the above technical solution are as follows: By adjusting the switching of three heat exchangers and electric two-way valve (3WV) and normally closed solenoid valve (SV), the refrigerant flow direction of the unit can be adjusted in various operating modes, realizing the functions of cooling, heating, total heat recovery of cooling, hot water production and defrosting of the unit, significantly reducing the phenomenon of oil accumulation in the system circuit and avoiding the problem of poor oil return of the unit compressor. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the refrigerant flow circulation under the heating operation mode of this utility model;

[0018] Figure 2 This is a schematic diagram of the refrigerant flow circulation under the refrigeration operation mode of this utility model;

[0019] Figure 3 This is a schematic diagram of the refrigerant flow circulation under the refrigeration total heat recovery operation mode of this utility model;

[0020] Figure 4 This is a schematic diagram of the refrigerant flow circulation under the hot water production operation mode of this utility model;

[0021] Figure 5 This is a schematic diagram showing the on / off state of the electric two-way valve of this utility model.

[0022] In the diagram, 1 is the compressor; 2 is the first heat exchanger; 3 is the second heat exchanger; 4 is the third heat exchanger; 5 is the first electric two-way valve; 6 is the second electric two-way valve; 7 is the third electric two-way valve; 8 is the fourth electric two-way valve; 9 is the fifth electric two-way valve; 10 is the sixth electric two-way valve; 11 is the first normally closed solenoid valve; 12 is the second normally closed solenoid valve; 13 is the liquid receiver; 14 is the gas-liquid separator; 15 is the oil separator; 16 is the check valve; 17 is the dryer filter; 18 is the electronic expansion valve; 19 is the first ball valve; 20 is the second ball valve; and 21 is the third normally closed solenoid valve. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Example

[0024] Reference Figure 1-4 A four-mode multi-pipe air-cooled heat pump unit includes a compressor 1, a first heat exchanger 2, a second heat exchanger 3, a third heat exchanger 4, a liquid storage tank 13, a gas-liquid separator 14, and an oil separator 15. The outlet of the compressor 1 is connected to the first heat exchanger 2 and the third heat exchanger 4 respectively through a first electric two-way valve 5, the inlet of the compressor 1 is connected to the gas-liquid separator 14, and an oil separator 15 is provided between the compressor 1 and the first electric two-way valve 5.

[0025] The outlet of the third heat exchanger 4 is connected to the inlet of the liquid storage tank 13 via the second electric two-way valve 6.

[0026] One end of the refrigerant pipe of the first heat exchanger 2 is connected to the first electric two-way valve 5 via the third electric two-way valve 7, and the other end is connected to the liquid storage tank 13 via the fourth electric two-way valve 8.

[0027] A one-way valve 16 is installed at the inlet of the liquid storage tank 13;

[0028] The outlet of the liquid storage tank 13 is connected to the second heat exchanger 3 through the fifth electric two-way valve 9. The second heat exchanger 3 is connected to the first electric two-way valve 5 through the first normally closed solenoid valve 11. The second heat exchanger 3 is connected to the inlet of the liquid storage tank 13 through the second normally closed solenoid valve 12. The second heat exchanger 3 is connected to the gas-liquid separator 14 through the sixth electric two-way valve 10. The third electric two-way valve 7 and the second electric two-way valve 6 are connected to the gas-liquid separator 14 through the sixth electric two-way valve 10.

[0029] The outlet of the liquid storage tank 13 is connected to the fifth electric two-way valve 9 through the dryer filter 17 and the electronic expansion valve 18. The fifth electric two-way valve 9 is connected to the fourth electric two-way valve 8.

[0030] Furthermore, a first ball valve 19 is provided between the liquid storage tank 13 and the dryer filter 17, and a second ball valve 20 is provided between the electronic expansion valve 18 and the fifth electric two-way valve 9.

[0031] Furthermore, the first heat exchanger 2 is a finned heat exchanger, the second heat exchanger 3 is a dry evaporator, and the third heat exchanger 4 is a shell-and-tube heat recovery heat exchanger.

[0032] Furthermore, a fan is installed on one side of the finned heat exchanger.

[0033] Furthermore, the second normally closed solenoid valve 12 is connected between the check valve 16 and the liquid storage tank 13.

[0034] Furthermore, the outlet of the liquid storage tank 13 is connected to the liquid injection inlet of the compressor 1 via a third normally closed solenoid valve 21. The third normally closed solenoid valve 21 is switched on and off according to the unit's exhaust operation. When the exhaust temperature of the compressor 1 or the motor temperature is too high, the third normally closed solenoid valve 21 is energized and opened.

[0035] The four-mode multi-pipe air-cooled heat pump unit in this embodiment 1 can realize cooling, heating, summer cooling full heat recovery, hot water production, and defrosting. The refrigerant flow circulation process in each operating mode is as follows:

[0036] In refrigeration operation mode, the refrigerant flow cycle is as follows: Compressor 1 draws in low-pressure superheated gaseous refrigerant, which, after passing through compressor 1, becomes high-pressure, high-temperature superheated refrigerant and flows to oil separator 15. It then passes through the first electric two-way valve 5 and the third electric two-way valve 7 to enter the finned heat exchanger. Through the cooperation of the finned heat exchanger and the fan, the refrigerant exchanges heat with the air, releasing heat and becoming a high-pressure, low-temperature subcooled liquid. It then sequentially passes through the fourth electric two-way valve 8, one-way valve 16, liquid receiver 13, first ball valve 19, and dryer filter 17. Through the throttling of electronic expansion valve 18, the refrigerant becomes a low-pressure, low-temperature gas-liquid two-phase state. It then passes through the second ball valve 20 and the fifth electric two-way valve 9 to enter the dry evaporator, where it exchanges heat with the refrigerant. The refrigerant absorbs heat from the refrigerant and becomes a low-pressure, high-temperature superheated gas, then passes through the sixth electric two-way valve 10 to enter the gas-liquid separator 14. After gas-liquid separation, the refrigerant is drawn into compressor 1, completing one refrigerant cycle. The dry evaporator is installed indoors, while the finned heat exchanger is installed outdoors. The finned heat exchanger and the fan work together as the condensation heat exchange unit of the system, and the dry evaporator serves as the evaporation heat exchange unit of the system. The refrigerant absorbs heat at the dry evaporator, which lowers the indoor air temperature and achieves refrigeration.

[0037] In heating operation mode, the refrigerant flow is as follows: Compressor 1 draws in low-pressure superheated gaseous refrigerant, which, after passing through compressor 1, becomes high-pressure, high-temperature superheated refrigerant. It flows to oil separator 15, passes through the first electric two-way valve 5 and the first normally closed solenoid valve 11, and enters the dry evaporator. The refrigerant exchanges heat with the heat transfer fluid in the dry evaporator, releasing heat and becoming a high-pressure, low-temperature subcooled liquid. It then sequentially passes through the second normally closed solenoid valve 12, the liquid receiver 13, the first ball valve 19, and the dryer filter 17, before passing through the electronic... Expansion valve 18 throttles the refrigerant, transforming it into a low-pressure, low-temperature gas-liquid two-phase state. It then passes through second ball valve 20, fifth electric two-way valve 9, and fourth electric two-way valve 8 before entering the finned heat exchanger. In conjunction with the finned heat exchanger and fan, the refrigerant exchanges heat with the air, absorbing heat and becoming a low-pressure, high-temperature superheated gas. It then passes through third electric two-way valve 7 and sixth electric two-way valve 10 before entering the gas-liquid separator 14. After gas-liquid separation, the refrigerant is drawn into compressor 1, completing one refrigerant cycle. The dry evaporator is located indoors, while the finned heat exchanger is located outdoors. The finned heat exchanger and fan work together as the system's evaporative heat exchange unit, while the dry evaporator serves as the system's condensative heat exchange unit. The refrigerant releases heat at the dry evaporator, raising the indoor air temperature and achieving heating.

[0038] In the refrigeration total heat recovery operation mode, the refrigerant flow cycle is as follows: Compressor 1 draws in low-pressure superheated gaseous refrigerant, which, after passing through compressor 1, becomes high-pressure, high-temperature superheated refrigerant and flows to oil separator 15. After passing through the first electric two-way valve 5, it enters the shell-and-tube heat recovery heat exchanger, where it exchanges heat with the refrigerant, releasing heat and becoming a high-pressure, low-temperature subcooled liquid. Then, it passes sequentially through the second electric two-way valve 6, one-way valve 16, liquid receiver 13, first ball valve 19, and dryer filter 17, and is throttled by electronic expansion valve 18, becoming a low-pressure, low-temperature gas-liquid two-phase state. Then, it enters the dry evaporator through the second ball valve 20 and the fifth electric two-way valve 9, where it exchanges heat with the refrigerant, absorbing heat from the refrigerant and becoming a low-pressure, high-temperature superheated gas. Finally, it passes through the sixth electric two-way valve 10 and enters the gas-liquid separator 14, where it undergoes gas-liquid separation and is drawn into compressor 1, completing one refrigerant cycle. The shell-and-tube heat recovery heat exchanger serves as the condensation heat exchange unit of the system, while the dry evaporator serves as the evaporation heat exchange unit.

[0039] In hot water operation mode, the refrigerant flow is as follows: Compressor 1 draws in low-pressure superheated gaseous refrigerant, which, after passing through compressor 1, becomes high-pressure, high-temperature superheated refrigerant; it flows to oil separator 15, passes through the first electric two-way valve 5, and enters the shell-and-tube heat recovery heat exchanger, where it exchanges heat with the refrigerant, releasing heat and becoming a high-pressure, low-temperature subcooled liquid; then it passes through the second electric two-way valve 6, one-way valve 16, liquid storage tank 13, first ball valve 19, and dryer filter 17, and then... The electronic expansion valve 18 throttles the refrigerant, transforming it into a low-pressure, low-temperature gas-liquid two-phase state. It then passes through the second ball valve 20, the fifth electric two-way valve 9, and the fourth electric two-way valve 8 before entering the finned heat exchanger. In conjunction with the fan, the finned heat exchanger exchanges heat with the air, absorbing heat and becoming a low-pressure, high-temperature superheated gas. This gas then passes through the third electric two-way valve 7 and the sixth electric two-way valve 10 before entering the gas-liquid separator 14. After gas-liquid separation, the refrigerant is drawn into the compressor 1, completing one refrigerant cycle. The shell-and-tube heat recovery heat exchanger serves as the system's condensation heat exchange unit, while the finned heat exchanger and fan work together as the system's evaporation heat exchange unit.

[0040] In defrost mode, the refrigerant flow is as follows: Figure 1As shown, compressor 1 draws in low-pressure superheated gaseous refrigerant, which, after passing through compressor 1, becomes high-pressure, high-temperature superheated refrigerant. It flows to oil separator 15, passes through first electric two-way valve 5 and third electric two-way valve 7, and enters finned heat exchanger. Through the finned heat exchanger, it exchanges heat with the frosted fins, releasing heat to melt the frost on the surface of the finned heat exchanger, turning the refrigerant into high-pressure, low-temperature subcooled liquid. Then, it passes through fourth electric two-way valve 8, one-way valve 16, liquid receiver 13, first ball valve 19, and dryer filter 17, and is throttled by electronic expansion valve 18, becoming a low-pressure, low-temperature gas-liquid two-phase state. It then passes through second ball valve 20 and fifth electric two-way valve 9, entering dry evaporator, where it exchanges heat with the refrigerant. The refrigerant absorbs heat from the refrigerant, becoming a low-pressure, high-temperature superheated gas, and then passes through sixth electric two-way valve 10, entering gas-liquid separator 14. After gas-liquid separation, the refrigerant is drawn into compressor 1, completing one refrigerant cycle. The finned heat exchanger serves as the condensing heat exchange unit of the system, while the dry evaporator serves as the evaporating heat exchange unit. During heating or hot water operation, the finned heat exchanger fins frost up due to heat absorption and the refrigerant temperature being below zero°C, requiring defrosting.

[0041] The first electric two-way valve 5, the second electric two-way valve 6, the third electric two-way valve 7, the fourth electric two-way valve 8, the fifth electric two-way valve 9, and the sixth electric two-way valve 10 all include energized and de-energized states, such as... Figure 5 As shown, in the power-on state, ports A and B are connected, and in the power-off state, ports AC are connected. The on / off states of the first electric two-way valve 5, the second electric two-way valve 6, the third electric two-way valve 7, the fourth electric two-way valve 8, the fifth electric two-way valve 9, the sixth electric two-way valve 10, the first normally closed solenoid valve 11, and the second normally closed solenoid valve 12 of the four-mode multi-pipe air-cooled heat pump unit in this embodiment 1 under each operating mode are shown in the table below.

[0042] Table 1. On / off status of electrically operated two-way valves and normally closed solenoid valves under various operating modes

[0043]

[0044] The compressor used in this embodiment 1 is a screw compressor, and the liquid receiver is a high-pressure, large-capacity liquid receiver used to balance the amount of refrigerant in each operating mode. The oil separator is a high-efficiency, large-capacity oil separator used to reduce the risk of oil accumulation in each mode.

Claims

1. A four-mode multi-pipe air-cooled heat pump unit, comprising a compressor (1), a first heat exchanger (2), a second heat exchanger (3), a third heat exchanger (4), a liquid storage tank (13), a gas-liquid separator (14), and an oil separator (15), characterized in that: The outlet of the compressor (1) is connected to the first heat exchanger (2) and the third heat exchanger (4) respectively through the first electric two-way valve (5). The inlet of the compressor (1) is connected to the gas-liquid separator (14). An oil separator (15) is installed between the compressor (1) and the first electric two-way valve (5). The outlet of the third heat exchanger (4) is connected to the inlet of the liquid storage tank (13) through the second electric two-way valve (6). One end of the refrigerant pipeline of the first heat exchanger (2) is connected to the first electric two-way valve (5) through the third electric two-way valve (7), and the other end is connected to the liquid storage tank (13) through the fourth electric two-way valve (8). The outlet of the storage tank (13) is connected to the second heat exchanger (3) through the fifth electric two-way valve (9). The second heat exchanger (3) is connected to the first electric two-way valve (5) through the first normally closed solenoid valve (11). The second heat exchanger (3) is connected to the inlet of the storage tank (13) through the second normally closed solenoid valve (12). The second heat exchanger (3) is connected to the gas-liquid separator (14) through the sixth electric two-way valve (10). The third electric two-way valve (7) and the second electric two-way valve (6) are connected to the gas-liquid separator (14) through the sixth electric two-way valve (10). The outlet of the storage tank (13) is connected to the fifth electric two-way valve (9) through the dryer filter (17) and the electronic expansion valve (18). The fifth electric two-way valve (9) is connected to the fourth electric two-way valve (8).

2. The four-mode multi-pipe air-cooled heat pump unit according to claim 1, characterized in that: A one-way valve (16) is installed at the inlet of the liquid storage tank (13).

3. A four-mode multi-pipe air-cooled heat pump unit according to claim 1, characterized in that: A first ball valve (19) is provided between the liquid storage tank (13) and the dryer filter (17), and a second ball valve (20) is provided between the electronic expansion valve (18) and the fifth electric two-way valve (9).

4. A four-mode multi-pipe air-cooled heat pump unit according to claim 1, characterized in that: The first heat exchanger (2) is a finned heat exchanger, the second heat exchanger (3) is a dry evaporator, and the third heat exchanger (4) is a shell-and-tube heat recovery heat exchanger.

5. A four-mode multi-pipe air-cooled heat pump unit according to claim 4, characterized in that: A fan is installed on one side of the finned heat exchanger.

6. A four-mode multi-pipe air-cooled heat pump unit according to claim 1, characterized in that: The second normally closed solenoid valve (12) is connected between the check valve (16) and the liquid storage tank (13).

7. A four-mode multi-pipe air-cooled heat pump unit according to claim 1 or 3, characterized in that: The outlet of the storage tank (13) is connected to the liquid injection inlet of the compressor (1) via a third normally closed solenoid valve (21).

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