An ultra-low temperature air source heat pump unit

Abstract

The present application belongs to the technical field of air source heat pump, and particularly relates to an ultralow-temperature air source heat pump unit, which can switch operation modes according to ambient temperature. In the severe cold condition of-20 DEG C, the system starts the first working mode, and adopts double-stage compression technology to reduce single-stage pressure ratio. When in the low-temperature environment of about-12 DEG C, the system switches to the fourth working mode, increases refrigerant circulation amount, and effectively improves heating capacity, so as to ensure that heat is little attenuated or even not attenuated. In the winter working condition of about 7 DEG C and summer refrigeration, the third and second working modes are respectively run, single-stage compression is adopted, and the air supplement port is closed to simplify the process and reduce energy consumption; the second working mode also recovers hot water while refrigerating through a heat recovery device. The present application switches refrigeration, heating and heat recovery modes through the coordinated control of various valve parts, adapts to the operation demand in four seasons, greatly improves system stability and reliability, and achieves the comprehensive goal of energy saving and emission reduction, and reducing heating cost.

Description

Technical Field

[0001] This invention belongs to the field of air source heat pump technology, and particularly relates to an ultra-low temperature air source heat pump unit. Background Technology

[0002] Traditional air source heat pumps exhibit significant technical bottlenecks in extremely cold environments (typically below -25°C or even -30°C): their heating efficiency decreases sharply as the ambient temperature drops, leading to unstable operation or even forced shutdown, severely impacting heating reliability; at the same time, their low energy utilization rate significantly increases heating costs, and they often experience severe heat output deficiencies when used for heating alone in winter, making it difficult to meet users' basic heating needs.

[0003] To address this, an ultra-low temperature air source heat pump unit is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide an ultra-low temperature air source heat pump unit to solve the above-mentioned problems.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A cryogenic air source heat pump unit includes: a high-pressure liquid receiver connected to the lower and left ports of an intercooler; a first solenoid valve and an auxiliary electronic expansion valve are installed between the high-pressure liquid receiver and the lower port of the intercooler; an eleventh solenoid valve is installed between the high-pressure liquid receiver and the left port of the intercooler; the upper port of the intercooler is connected to the upper and lower inlets of a high-pressure stage compressor; a fourth solenoid valve is installed between the intercooler and the upper inlet of the high-pressure stage compressor; a fifth solenoid valve is installed between the intercooler and the lower inlet of the high-pressure stage compressor; the outlet of the high-pressure stage compressor is connected to the lower port of a first four-way reversing valve; the right port of the first four-way reversing valve is connected to the lower port of a third four-way reversing valve; the right port of the third four-way reversing valve is connected to the heat outlet of a heat exchanger and a heat recovery unit; the heat recovery unit and the second opening of the heat exchanger are connected; a third solenoid valve is installed between the third four-way reversing valve and the heat outlet of the heat exchanger; a second solenoid valve is installed between the heat recovery unit and the heat exchanger; and the first opening of the heat exchanger is connected to the right port of the intercooler. A tenth solenoid valve is installed between the first opening of the heat exchanger and the intercooler. A main electronic expansion valve is installed between the intercooler and the tenth solenoid valve. The upper port of the third four-way reversing valve is connected to the left port of the second four-way reversing valve and the upper port of the first four-way reversing valve. An eighth solenoid valve is installed between the third four-way reversing valve and the left port of the second four-way reversing valve. A seventh solenoid valve is installed between the third four-way reversing valve and the upper port of the first four-way reversing valve. The left port of the third four-way reversing valve is connected to the high-pressure liquid receiver and the intercooler. The left port of the first four-way reversing valve is connected to the left port of the second four-way reversing valve. A twelfth solenoid valve is installed between the left port of the third four-way reversing valve and the left port of the intercooler. The upper port of the second four-way reversing valve is connected to the inlet of the low-pressure stage compressor. The outlet of the low-pressure stage compressor is connected to the lower port of the second four-way reversing valve. The right port of the second four-way reversing valve is connected to the upper port of the first four-way reversing valve. A sixth solenoid valve is installed between the right port of the second four-way reversing valve and the upper port of the first four-way reversing valve. The left port of the first four-way reversing valve is connected to the lower inlet of the high-pressure stage compressor.

[0007] In the first working mode, the working fluid flows out of the high-pressure liquid receiver and is divided into two streams. The two streams of working fluid enter the lower and left ports of the intercooler, respectively. One stream of working fluid flows out of the right port of the intercooler and passes sequentially through the main electronic expansion valve, heat exchanger, low-pressure stage compressor, and lower inlet of the high-pressure stage compressor. The other stream of working fluid flows out of the upper port of the intercooler and enters the lower inlet of the high-pressure stage compressor. Both streams of working fluid flow from the outlet of the high-pressure stage compressor to the high-pressure liquid receiver.

[0008] In the second operating mode, the working fluid flows out from the outlet of the high-pressure stage compressor, and flows sequentially through the heat recovery unit, heat exchanger, main electronic expansion valve, and intercooler before flowing to the lower inlet of the high-pressure stage compressor.

[0009] In the third working mode, the working fluid flows out of the high-pressure liquid receiver, sequentially through the intercooler, the main electronic expansion valve, the heat exchanger, and the lower inlet of the high-pressure stage compressor, and then flows out of the outlet of the high-pressure stage compressor and returns to the high-pressure liquid receiver.

[0010] In the fourth operating mode, the working fluid flows out of the high-pressure liquid receiver and is divided into two streams. The two streams of working fluid enter the lower and left ports of the intercooler, respectively. One stream of working fluid flows out of the upper port of the intercooler and enters the upper inlet of the high-pressure stage compressor. The other stream of working fluid passes sequentially through the main electronic expansion valve, heat exchanger, and lower inlet of the high-pressure stage compressor. Both streams of working fluid flow out of the outlet of the high-pressure stage compressor at the same time and return to the high-pressure liquid receiver.

[0011] Preferably, a drying filter is installed between the main electronic expansion valve and the right port of the intercooler, and between the main electronic expansion valve and the tenth solenoid valve.

[0012] Preferably, the first opening of the heat exchanger is connected to the high-pressure liquid receiver, and a ninth solenoid valve is provided between the first opening of the heat exchanger and the high-pressure liquid receiver.

[0013] Preferably, the lower inlet of the high-pressure stage compressor is connected to the outlet of the gas-liquid separator, and the inlet of the gas-liquid separator is connected to the left port of the fifth solenoid valve and the first four-way reversing valve.

[0014] Preferably, the inlet of the low-pressure stage compressor is connected to the outlet of another gas-liquid separator, and the inlet of the other gas-liquid separator is connected to the upper port of the second four-way reversing valve.

[0015] Preferably, the heat exchanger includes a finned heat exchanger.

[0016] Preferably, a shell-and-tube heat exchanger is provided between the left port of the third four-way reversing valve and the high-pressure liquid receiver. The shell-and-tube heat exchanger is located between the twelfth solenoid valve and the left port of the third four-way reversing valve. A shut-off valve is provided between the shell-and-tube heat exchanger and the left port of the third four-way reversing valve. Another shut-off valve is provided between the shell-and-tube heat exchanger and the twelfth solenoid valve. The other shut-off valve is located between the shell-and-tube heat exchanger and the high-pressure liquid receiver.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects:

[0018] This invention provides an ultra-low temperature air source heat pump unit that can switch operating modes according to different ambient temperatures to ensure efficient and stable operation of the system under all conditions. In frigid conditions of -20℃, the system activates the first operating mode, employing two-stage compression technology. This effectively reduces the single-stage pressure ratio, significantly improving compressor efficiency and extending equipment lifespan. When the ambient temperature rises to around -12℃, the system switches to the fourth operating mode. In this mode, vapor injection enthalpy enhancement technology is applied. By controlling the fourth solenoid valve and utilizing the intercooler, the refrigerant circulation is increased, significantly improving heating capacity and ensuring minimal or no heat loss during winter heating alone. In winter conditions of around 7℃, the system operates in the third operating mode, using single-stage compression and closing the air inlet, simplifying the system process and reducing energy consumption. In summer, the system enters the second operating mode, again using single-stage compression and closing the air inlet to optimize energy efficiency. Simultaneously, through the built-in heat recovery unit, domestic hot water is recovered while cooling is achieved, maintaining its temperature at no less than 60℃, achieving green and energy-saving effects. This invention achieves automatic switching between cooling, heating and heat recovery modes through the coordinated control of various valves, which not only adapts to the operating needs of all four seasons, but also improves the stability and reliability of the system operation, ultimately achieving the goals of energy conservation, emission reduction and lower heating costs. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0021] The components are as follows: 1. High-pressure liquid receiver; 2. Shut-off valve; 3. Shell and tube heat exchanger; 5. Dryer filter; 6. Main electronic expansion valve; 7. Intercooler; 8. Heat exchanger; 9. Heat recovery unit; 10. Gas-liquid separator; 11. High-pressure stage compressor; 12. First four-way reversing valve; 13. Low-pressure stage compressor; 14. Auxiliary electronic expansion valve; 15. Second four-way reversing valve; 16. Third four-way reversing valve; 4-1. First solenoid valve; 4-2. Second solenoid valve; 4-3. Third solenoid valve; 4-4. Fourth solenoid valve; 4-5. Fifth solenoid valve; 4-6. Sixth solenoid valve; 4-7. Seventh solenoid valve; 4-8. Eighth solenoid valve; 4-9. Ninth solenoid valve; 4-10. Tenth solenoid valve; 4-11. Eleventh solenoid valve; 4-12. Twelfth solenoid valve. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Reference Figure 1This invention discloses an ultra-low temperature air source heat pump unit, comprising: a high-pressure liquid receiver 1, the high-pressure liquid receiver 1 being connected to the lower port and left port of an intercooler 7; a first solenoid valve 4-1 and an auxiliary electronic expansion valve 14 being arranged between the high-pressure liquid receiver 1 and the lower port of the intercooler 7; an eleventh solenoid valve 4-11 being arranged between the high-pressure liquid receiver 1 and the left port of the intercooler 7; the upper port of the intercooler 7 being connected to the upper inlet and lower inlet of a high-pressure stage compressor 11; a fourth solenoid valve 4-4 being arranged between the intercooler 7 and the upper inlet of the high-pressure stage compressor 11; and the intercooler 7 and the high-pressure stage compressor 11 being connected to the lower port of the intercooler 7. A fifth solenoid valve 4-5 is installed between the lower inlet and outlet. The outlet of the high-pressure stage compressor 11 is connected to the lower port of the first four-way reversing valve 12. The right port of the first four-way reversing valve 12 is connected to the lower port of the third four-way reversing valve 16. The right port of the third four-way reversing valve 16 is connected to the heat outlet of the heat exchanger 8 and the heat recovery unit 9. The heat recovery unit 9 and the second opening of the heat exchanger 8 are connected. A third solenoid valve 4-3 is installed between the third four-way reversing valve 16 and the heat outlet of the heat exchanger 8. A second solenoid valve 4-2 is installed between the heat recovery unit 9 and the heat exchanger 8. The first opening of the heat exchanger 8 is connected to the right port of the intercooler 7. A tenth solenoid valve 4-10 is installed between the first opening of heat exchanger 8 and intercooler 7. A main electronic expansion valve 6 is installed between intercooler 7 and the tenth solenoid valve 4-10. The upper port of the third four-way reversing valve 16 is connected to the left port of the second four-way reversing valve 15 and the upper port of the first four-way reversing valve 12. An eighth solenoid valve 4-8 is installed between the third four-way reversing valve 16 and the left port of the second four-way reversing valve 15. A seventh solenoid valve 4-7 is installed between the third four-way reversing valve 16 and the upper port of the first four-way reversing valve 12. The left port of the third four-way reversing valve 16 is connected to the high-pressure liquid receiver 1 and the intercooler 7. The left port of the intercooler 7 is connected to the left port of the third four-way reversing valve 16 and the left port of the intercooler 7. The twelfth solenoid valve 4-12 is installed between the left port of the third four-way reversing valve 16 and the left port of the intercooler 7. The upper port of the second four-way reversing valve 15 is connected to the inlet of the low-pressure stage compressor 13. The outlet of the low-pressure stage compressor 13 is connected to the lower port of the second four-way reversing valve 15. The right port of the second four-way reversing valve 15 is connected to the upper port of the first four-way reversing valve 12. The sixth solenoid valve 4-6 is installed between the right port of the second four-way reversing valve 15 and the upper port of the first four-way reversing valve 12. The left port of the first four-way reversing valve 12 is connected to the lower inlet of the high-pressure stage compressor 11.

[0025] In the first working mode, the working fluid flows out of the high-pressure liquid receiver 1 and is divided into two streams. The two streams of working fluid enter the lower and left ports of the intercooler 7, respectively. One stream of working fluid flows out from the right port of the intercooler 7 and passes sequentially through the main electronic expansion valve 6, heat exchanger 8, low-pressure stage compressor 13, and the lower inlet of the high-pressure stage compressor 11. The other stream of working fluid flows out from the upper port of the intercooler 7 and enters the lower inlet of the high-pressure stage compressor 11. Both streams of working fluid flow from the outlet of the high-pressure stage compressor 11 to the high-pressure liquid receiver 1.

[0026] In the second operating mode, the working fluid flows out from the outlet of the high-pressure stage compressor 11, and flows sequentially through the heat recovery unit 9, heat exchanger 8, main electronic expansion valve 6, and intercooler 7 before flowing to the lower inlet of the high-pressure stage compressor 11.

[0027] In the third working mode, the working fluid flows out of the high-pressure liquid receiver 1, sequentially through the intercooler 7, the main electronic expansion valve 6, the heat exchanger 8, and the lower inlet of the high-pressure stage compressor 11, and then flows out of the outlet of the high-pressure stage compressor 11 and returns to the high-pressure liquid receiver 1.

[0028] In the fourth operating mode, the working fluid flows out of the high-pressure liquid receiver 1 and is divided into two streams. The two streams of working fluid enter the lower and left ports of the intercooler 7, respectively. One stream of working fluid flows out from the upper port of the intercooler 7 and enters the upper inlet of the high-pressure stage compressor 11. The other stream of working fluid passes sequentially through the main electronic expansion valve 6, the heat exchanger 8, and the lower inlet of the high-pressure stage compressor 11. Both streams of working fluid flow out from the outlet of the high-pressure stage compressor 11 and return to the high-pressure liquid receiver 1.

[0029] To further optimize the design, a dryer filter 5 is installed between the main electronic expansion valve 6 and the right port of the intercooler 7, and between the main electronic expansion valve 6 and the tenth solenoid valve 4-10.

[0030] In a further optimized design, the first opening of the heat exchanger 8 is connected to the high-pressure liquid receiver 1, and a ninth solenoid valve 4-9 is installed between the first opening of the heat exchanger 8 and the high-pressure liquid receiver 1.

[0031] In a further optimized design, the lower inlet of the high-pressure stage compressor 11 is connected to the outlet of the gas-liquid separator 10, and the inlet of the gas-liquid separator 10 is connected to the fifth solenoid valve 4-5 and the left port of the first four-way reversing valve 12.

[0032] In a further optimized design, the inlet of the low-pressure stage compressor 13 is connected to the outlet of another gas-liquid separator 10, and the inlet of the other gas-liquid separator 10 is connected to the upper port of the second four-way reversing valve 15.

[0033] The design was further optimized, and heat exchanger 8 includes a finned heat exchanger.

[0034] In a further optimized design, a shell-and-tube heat exchanger 3 is installed between the left port of the third four-way directional valve 16 and the high-pressure liquid receiver 1. The shell-and-tube heat exchanger 3 is located between the twelfth solenoid valve 4-12 and the left port of the third four-way directional valve 16. A shut-off valve 2 is installed between the shell-and-tube heat exchanger 3 and the left port of the third four-way directional valve 16. Another shut-off valve 2 is installed between the shell-and-tube heat exchanger 3 and the twelfth solenoid valve 4-12. The other shut-off valve 2 is located between the shell-and-tube heat exchanger 3 and the high-pressure liquid receiver 1.

[0035] The ultra-low temperature air source heat pump unit of this invention operates in four modes:

[0036] First working mode: At this time, the outdoor temperature is about -20℃. Under this condition, the first solenoid valve 4-1, the third solenoid valve 4-3, the fifth solenoid valve 4-5, the sixth solenoid valve 4-6, the eighth solenoid valve 4-8, the tenth solenoid valve 4-10, the auxiliary electronic expansion valve 14, and the eleventh solenoid valve 4-11 are open, while the second solenoid valve 4-2, the fourth solenoid valve 4-4, the seventh solenoid valve 4-7, the ninth solenoid valve 4-9, and the twelfth solenoid valve 4-12 are closed.

[0037] The working fluid flows out of the high-pressure reservoir 1 and splits into two paths. One path passes through the first solenoid valve 4-1 and the auxiliary electronic expansion valve 14, becoming a low-temperature, low-pressure working fluid, and then enters the lower inlet of the intercooler 7. The other path passes through the eleventh solenoid valve 4-11 and enters the left inlet of the intercooler 7. After heat exchange in the intercooler 7, part of the working fluid is cooled and flows out from the right inlet of the intercooler 7. It then passes sequentially through the dryer filter 5, the main electronic expansion valve 6, and the tenth solenoid valve 4-10, before passing through the heat exchanger 8 and absorbing heat from the environment. The working fluid heats up and evaporates. The heated working fluid then passes through the third solenoid valve 4-3 and then through the... The working fluid enters the third four-way reversing valve 16 through the right port of the three four-way reversing valve 16, then flows out through the upper port of the third four-way reversing valve 16, passes through the eighth solenoid valve 4-8, enters the left port of the second four-way reversing valve 15, flows out through the upper port of the second four-way reversing valve 15, enters the gas-liquid separator 10, and then enters the low-pressure stage compressor 13 for compression. The working fluid then enters the lower port of the second four-way reversing valve 15, flows out through the right port of the second four-way reversing valve 15, passes through the sixth solenoid valve 4-6, enters the upper port of the first four-way reversing valve 12, and flows out from the left port of the first four-way reversing valve 12 into the gas-liquid separator 10.

[0038] The hotter working fluid passes through the upper port of the intercooler 7 and then through the fifth solenoid valve 4-5. It mixes with the working fluid flowing out from the left port of the first four-way reversing valve 12 and enters the gas-liquid separator 10. After passing through the gas-liquid separator 10, the working fluid enters the high-pressure stage compressor 11. The high-pressure stage compressor 11 performs secondary compression on the working fluid and then discharges it. Subsequently, the working fluid enters through the lower port of the first four-way reversing valve 12, changes direction within the first four-way reversing valve 12, and flows out through the right port of the first four-way reversing valve 12. Then, it enters the lower port of the third four-way reversing valve 16 along the pipeline and flows out through the left port of the third four-way reversing valve 16. The working fluid sequentially passes through the shell and tube heat exchanger 3 to dissipate heat and condense to the outside, and finally returns to the high-pressure liquid receiver 1, completing one cycle.

[0039] Second working mode: In summer, the ambient temperature is high and cooling is required. Under this condition, the second solenoid valve 4-2, the seventh solenoid valve 4-7, the tenth solenoid valve 4-10, and the twelfth solenoid valve 4-12 are open, while the first solenoid valve 4-1, the third solenoid valve 4-3, the fourth solenoid valve 4-4, the fifth solenoid valve 4-5, the sixth solenoid valve 4-6, the eighth solenoid valve 4-8, the ninth solenoid valve 4-9, the eleventh solenoid valve 4-11, and the auxiliary electronic expansion valve 14 are closed.

[0040] The working fluid flows out from the high-pressure stage compressor 11. At this time, the working fluid is a high-temperature and high-pressure gas. The working fluid enters the lower port of the first four-way reversing valve 12, flows out from the right port of the first four-way reversing valve 12, enters the lower port of the third four-way reversing valve 16, and flows out from the right port of the third four-way reversing valve 16. Then, the working fluid enters the heat recovery unit 9 to recover the heat in the working fluid. The working fluid flows out from the heat recovery unit 9 and enters the heat exchanger 8 for heat dissipation. After heat dissipation, the working fluid sequentially passes through the second solenoid valve 4-2 and the tenth solenoid valve 4-10, and is then throttled by the main electronic expansion valve 6 to become a low-temperature and low-pressure working fluid. After the dryer filter 5, the product enters the left port of the intercooler 7, where it absorbs heat and evaporates. Then, it flows out through the right port of the intercooler 7, sequentially passing through the twelfth solenoid valve 4-12 and the shut-off valve 2 before entering the shell-and-tube heat exchanger 3 for secondary heat absorption and evaporation. Afterward, it enters the left port of the third four-way reversing valve 16, flows out through the upper port of the third four-way reversing valve 16, flows through the seventh solenoid valve 4-7, enters the upper port of the first four-way reversing valve 12, flows out through the left port of the first four-way reversing valve 12, and enters the gas-liquid separator 10. Finally, it enters the high-pressure stage compressor 11, completing one cycle.

[0041] Third working mode: This is winter, with an air temperature of around 7℃. Under this condition, the third solenoid valve 4-3, the seventh solenoid valve 4-7, the tenth solenoid valve 4-10, and the eleventh solenoid valve 4-11 are open, while the first solenoid valve 4-1, the second solenoid valve 4-2, the fourth solenoid valve 4-4, the fifth solenoid valve 4-5, the sixth solenoid valve 4-6, the eighth solenoid valve 4-8, the ninth solenoid valve 4-9, the twelfth solenoid valve 4-12, and the auxiliary electronic expansion valve 14 are closed.

[0042] The working fluid flows out of the high-pressure reservoir 1, passes through the eleventh solenoid valve 4-11 and enters the left port of the intercooler 7. It then flows out from the right port of the intercooler 7, sequentially passing through the dryer filter 5, the main electronic expansion valve 6, and the tenth solenoid valve 4-10 before entering the heat exchanger 8 for heat exchange. After exiting the heat exchanger 8, it passes through the third solenoid valve 4-3 and enters the right port of the third four-way directional valve 16. It then flows out from the upper port of the third four-way directional valve 16, passes through the seventh solenoid valve 4-7, and enters the first four-way directional valve. The upper port of valve 12 flows out from the left port of the first four-way reversing valve 12, then passes through the gas-liquid separator 10 and enters the high-pressure stage compressor 11. After flowing out of the high-pressure stage compressor 11, it enters the lower port of the first four-way reversing valve 12, flows out through the right port of the first four-way reversing valve 12 and enters the lower port of the third four-way reversing valve 16. After flowing out through the left port of the third four-way reversing valve 16, it sequentially passes through the shell-and-tube heat exchanger 3 and the shut-off valve 2, and then enters the high-pressure liquid receiver 1 to complete the cycle.

[0043] The fourth working mode is in winter, with a temperature of around -12℃. Under this condition, the first solenoid valve 4-1, the third solenoid valve 4-3, the fourth solenoid valve 4-4, the seventh solenoid valve 4-7, the tenth solenoid valve 4-10, the eleventh solenoid valve 4-11, and the auxiliary electronic expansion valve 14 are open, while the second solenoid valve 4-2, the fifth solenoid valve 4-5, the sixth solenoid valve 4-6, the eighth solenoid valve 4-8, the ninth solenoid valve 4-9, and the twelfth solenoid valve 4-12 are closed.

[0044] The working fluid flows out of the high-pressure liquid receiver 1 and is divided into two paths. One path enters the left port of the intercooler 7 through the eleventh solenoid valve 4-11, and the other path enters the lower port of the intercooler 7 through the first solenoid valve 4-1 and the auxiliary electronic expansion valve 14. Heat exchange is completed in the intercooler 7. One path flows out through the right port of the intercooler 7, passes through the dryer filter 5, the main electronic expansion valve 6, and the tenth solenoid valve 4-10 in sequence, and then enters the heat exchanger 8. After flowing out of the heat exchanger 8, it passes through the third solenoid valve 4-3 and enters the right port of the third four-way reversing valve 16. It flows out from the upper port of the third four-way reversing valve 16, passes through the seventh solenoid valve 4-7 and enters the upper port of the first four-way reversing valve 12. It flows out from the left port of the first four-way reversing valve 12 and enters the gas-liquid separator 10, and then enters the high-pressure stage compressor 11.

[0045] Another path flows out from the upper outlet of the intercooler 7 and then directly into the high-pressure stage compressor 11 through the fourth solenoid valve 4-4;

[0046] Two working fluids flow out simultaneously from the high-pressure stage compressor 11, then enter the lower port of the first four-way reversing valve 12, flow out through the right port of the first four-way reversing valve 12 and enter the lower port of the third four-way reversing valve 16, and flow out through the left port of the third four-way reversing valve 16 in sequence through the shell and tube heat exchanger 3 and the shut-off valve 2 before entering the high-pressure liquid receiver 1 to complete the cycle.

[0047] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0048] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An ultra-low temperature air source heat pump unit, characterized in that, include: A high-pressure liquid receiver (1) is connected to the lower and left ports of an intercooler (7). A first solenoid valve (4-1) and an auxiliary electronic expansion valve (14) are installed between the high-pressure liquid receiver (1) and the lower port of the intercooler (7). An eleventh solenoid valve (4-11) is installed between the high-pressure liquid receiver (1) and the left port of the intercooler (7). The upper port of the intercooler (7) is connected to the upper and lower inlets of a high-pressure stage compressor (11). A fourth solenoid valve (4-4) is installed between the intercooler (7) and the upper inlet of the high-pressure stage compressor (11). A fifth solenoid valve (4-5) is installed between the intercooler (7) and the lower inlet of the high-pressure stage compressor (11). The outlet of the high-pressure stage compressor (11) is connected to the first The lower port of the four-way reversing valve (12) is connected to the lower port of the third four-way reversing valve (16). The right port of the third four-way reversing valve (16) is connected to the heat outlet of the heat exchanger (8) and the heat recovery unit (9). The heat recovery unit (9) and the second opening of the heat exchanger (8) are connected. A third solenoid valve (4-3) is installed between the third four-way reversing valve (16) and the heat outlet of the heat exchanger (8). A second solenoid valve (4-2) is installed between the heat recovery unit (9) and the heat exchanger (8). The first opening of the heat exchanger (8) is connected to the right port of the intercooler (7). A tenth solenoid valve (4-10) is installed between the first opening of the heat exchanger (8) and the intercooler (7). The intercooler (7) and the tenth solenoid valve... A main electronic expansion valve (6) is provided between valves (4-10). The upper port of the third four-way reversing valve (16) is connected to the left port of the second four-way reversing valve (15) and the upper port of the first four-way reversing valve (12). An eighth solenoid valve (4-8) is provided between the left port of the third four-way reversing valve (16) and the second four-way reversing valve (15). A seventh solenoid valve (4-7) is provided between the upper port of the third four-way reversing valve (16) and the first four-way reversing valve (12). The left port of the third four-way reversing valve (16) is connected to the left port of the high-pressure liquid reservoir (1) and the intercooler (7). A twelfth solenoid valve (4-12) is provided between the left port of the third four-way reversing valve (16) and the left port of the intercooler (7). A shell-and-tube heat exchanger (3) is provided between the left port of the 16) and the high-pressure liquid receiver (1). The shell-and-tube heat exchanger (3) is located between the left port of the twelfth solenoid valve (4-12) and the third four-way reversing valve (16). The upper port of the second four-way reversing valve (15) is connected to the inlet of the low-pressure stage compressor (13). The outlet of the low-pressure stage compressor (13) is connected to the lower port of the second four-way reversing valve (15). The right port of the second four-way reversing valve (15) is connected to the upper port of the first four-way reversing valve (12). A sixth solenoid valve (4-6) is provided between the right port of the second four-way reversing valve (15) and the upper port of the first four-way reversing valve (12). The left port of the first four-way reversing valve (12) is connected to the lower inlet of the high-pressure stage compressor (11). In the first working mode, the working fluid flows out of the high-pressure liquid receiver (1) and is divided into two streams. The two streams of working fluid enter the lower and left ports of the intercooler (7) respectively. One stream of working fluid flows out from the right port of the intercooler (7) and passes sequentially through the main electronic expansion valve (6), heat exchanger (8), low-pressure stage compressor (13), and the lower inlet of the high-pressure stage compressor (11). The other stream of working fluid flows out from the upper port of the intercooler (7) and enters the lower inlet of the high-pressure stage compressor (11). The two streams of working fluid flow from the outlet of the high-pressure stage compressor (11) to the high-pressure liquid receiver (1). In the second working mode, the working fluid flows out from the outlet of the high-pressure stage compressor (11), and flows sequentially through the heat recovery unit (9), heat exchanger (8), main electronic expansion valve (6), and intercooler (7) to the lower inlet of the high-pressure stage compressor (11); In the third working mode, the working fluid flows out from the high-pressure reservoir (1), sequentially through the intercooler (7), the main electronic expansion valve (6), the heat exchanger (8), and the lower inlet of the high-pressure stage compressor (11), and flows out from the outlet of the high-pressure stage compressor (11) and returns to the high-pressure reservoir (1). In the fourth working mode, the working fluid flows out of the high-pressure liquid receiver (1) and is divided into two streams. The two streams of working fluid enter the lower and left ports of the intercooler (7) respectively. One stream of working fluid flows out from the upper port of the intercooler (7) and enters the upper inlet of the high-pressure stage compressor (11). The other stream of working fluid passes sequentially through the main electronic expansion valve (6), the heat exchanger (8), and the lower inlet of the high-pressure stage compressor (11). Both streams of working fluid flow out from the outlet of the high-pressure stage compressor (11) and return to the high-pressure liquid receiver (1).

2. The ultra-low temperature air source heat pump unit according to claim 1, characterized in that: A dryer filter (5) is installed between the main electronic expansion valve (6) and the right port of the intercooler (7), and between the main electronic expansion valve (6) and the tenth solenoid valve (4-10).

3. The ultra-low temperature air source heat pump unit according to claim 1, characterized in that: The first opening of the heat exchanger (8) is connected to the high-pressure liquid reservoir (1), and a ninth solenoid valve (4-9) is provided between the first opening of the heat exchanger (8) and the high-pressure liquid reservoir (1).

4. The ultra-low temperature air source heat pump unit according to claim 1, characterized in that: The lower inlet of the high-pressure stage compressor (11) is connected to the outlet of the gas-liquid separator (10), and the inlet of the gas-liquid separator (10) is connected to the left port of the fifth solenoid valve (4-5) and the first four-way reversing valve (12).

5. The ultra-low temperature air source heat pump unit according to claim 1, characterized in that: The inlet of the low-pressure stage compressor (13) is connected to the outlet of another gas-liquid separator (10), and the inlet of the other gas-liquid separator (10) is connected to the upper port of the second four-way reversing valve (15).

6. The ultra-low temperature air source heat pump unit according to claim 1, characterized in that: The heat exchanger (8) includes a finned heat exchanger.

7. The ultra-low temperature air source heat pump unit according to claim 1, characterized in that: A shut-off valve (2) is provided between the shell-and-tube heat exchanger (3) and the left port of the third four-way reversing valve (16). Another shut-off valve (2) is provided between the shell-and-tube heat exchanger (3) and the twelfth solenoid valve (4-12). The other shut-off valve (2) is located between the shell-and-tube heat exchanger (3) and the high-pressure liquid receiver (1).

Images