A heat pump unit

Abstract

The present invention provides a heat pump unit, comprising a compressor, a first heat exchanger, a throttling element, a second heat exchanger, a liquid storage tank, a first heating assembly, and a controller; the exhaust port of the compressor is connected to the input end of the liquid storage tank through the first heat exchanger, the throttling element, and the second heat exchanger in sequence, the output end of the liquid storage tank is connected to the return air port of the compressor, and the first heating assembly is disposed on the liquid storage tank; the controller is configured to control the first heating assembly to heat the liquid storage tank after receiving a power-on signal, and to control the compressor to start after the liquid storage tank is heated. Compared to the prior art, the present invention provides a liquid storage tank for containing a mixture of refrigerant and refrigeration oil at the return air port of the compressor, and heats the liquid storage tank after receiving a power-on signal, so that the refrigerant in the liquid storage tank evaporates due to the heat and separates from the refrigeration oil, thereby alleviating the adverse effects of starting the compressor with liquid on the compressor reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pumps, in particular to a heat pump unit. Background Art

[0002] Heat pump unit is a widely used heating equipment. Compared with electric heating equipment, heat pump unit has higher heating efficiency, more energy-saving and environmentally friendly. Figure 1 As shown, the heat pump unit of the prior art includes a compressor 10, a first heat exchanger 30, a throttling element 40 and a second heat exchanger 50. The compressor 10 is provided with a return air port 11 and an exhaust port 12. The exhaust port 12 is connected to the return air port 11 through the first heat exchanger 30, the throttling element 40 and the second heat exchanger 50 in sequence. Generally, the first heat exchanger 30 is arranged indoors and the second heat exchanger 50 is arranged outdoors. When the heat pump unit is running, the compressor 10 compresses the refrigerant and transports it to the first heat exchanger 30. The temperature and pressure of the compressed refrigerant increase, and heat is released in the first heat exchanger 30. The refrigerant after releasing heat flows to the second heat exchanger 50 through the throttling element 40. The refrigerant after releasing heat expands when passing through the throttling element 40. The throttling element 40 reduces the temperature of the refrigerant. The refrigerant with reduced temperature absorbs heat in the second heat exchanger 50. The refrigerant after absorbing heat is transported back to the compressor 10 and compressed by the compressor 10 again, thereby forming a refrigerant cycle. As a result, the refrigerant absorbs heat in the second heat exchanger 50 and transfers the heat to the first heat exchanger 30 for release, thereby achieving heating of the room. Summary of the Invention

[0003] Based on this, an object of the present invention is to provide a heat pump unit that can operate normally in a low temperature environment.

[0004] The heat pump unit of the present invention includes a compressor, a first heat exchanger, a throttling element, a second heat exchanger, a liquid storage tank, a first heating assembly, and a controller; the liquid storage tank has an interior forming a receiving chamber, and the liquid storage tank is provided with an input end and an output end communicating with the receiving chamber, wherein the output end is higher than the bottom of the receiving chamber;

[0005] The exhaust port of the compressor is connected to the input end of the liquid storage tank through the first heat exchanger, the throttling element, and the second heat exchanger in sequence, and the output end of the liquid storage tank is connected to the return air port of the compressor. The first heating component is disposed on the liquid storage tank; the controller is electrically connected to the compressor and the first heating component;

[0006] The controller is used to control the first heating component to heat the liquid storage tank after receiving a power-on signal, and is used to control the compressor to start after heating the liquid storage tank.

[0007] Furthermore, it further comprises an ambient temperature sensor, wherein the ambient temperature sensor is electrically connected to the controller;

[0008] The controller is further configured to obtain the ambient temperature through the ambient temperature sensor, and control the duration for which the first heating component heats the liquid storage tank based on the obtained ambient temperature and a previously established correspondence between the ambient temperature and the heating duration.

[0009] Furthermore, the controller is also electrically connected to the throttling element;

[0010] The controller is further configured to control the throttling element to be adjusted to a minimum opening after receiving a shutdown signal, and to control the compressor to stop running after the throttling element is adjusted to the minimum opening.

[0011] Furthermore, after controlling the throttling element to be adjusted to a minimum opening and before controlling the compressor to stop running, the controller is further configured to control the compressor to increase its frequency.

[0012] Optionally, the system further includes a first control valve, the first control valve being disposed between the exhaust port of the compressor and the first heat exchanger, and the first control valve being electrically connected to the controller;

[0013] The controller is further configured to control the first control valve to close after receiving a shutdown signal, and control the compressor to stop running after the first control valve is closed.

[0014] Furthermore, it further comprises a second heating component disposed at the bottom of the compressor, wherein the second heating component is electrically connected to the controller;

[0015] The controller is further configured to control the second heating assembly to heat the bottom of the compressor when heating the liquid storage tank.

[0016] Furthermore, it further comprises a second control valve provided between the output end of the liquid storage tank and the return air port of the compressor, wherein the second control valve is electrically connected to the controller;

[0017] The controller is further configured to control the second control valve to close after the compressor stops running, and to control the second control valve to open after the liquid storage tank is heated and before the compressor starts.

[0018] Furthermore, it further comprises a third control valve provided between the input end of the liquid storage tank and the second heat exchanger, wherein the third control valve is electrically connected to the controller;

[0019] The controller is further configured to control the third control valve to close after the compressor stops running, and to control the third control valve to open after the liquid storage tank is heated and before the compressor starts.

[0020] Furthermore, the accommodating cavity formed in the liquid storage tank is columnar, and the input end and the output end are respectively arranged at two ends of the accommodating cavity.

[0021] Furthermore, the length of the accommodating cavity is 8-10 times its diameter.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. A liquid storage tank for containing a mixture of refrigerant and refrigeration oil is set at the return air port of the compressor. After the heat pump unit receives the start-up signal, it heats the liquid storage tank to evaporate the refrigerant in the liquid storage tank and separate it from the refrigeration oil. Then the compressor is started, thereby reducing the impact of the mixture of refrigerant and refrigeration oil on the startup and operation of the compressor;

[0024] 2. After receiving the power-on signal, the ambient temperature is obtained and the heating time of the liquid storage tank is determined by the correspondence between the preset ambient temperature and the heating time. In this way, the startup time of the heat pump unit can be shortened while ensuring that the refrigerant and the refrigeration oil can be completely separated;

[0025] 3. After the heat pump unit receives the shutdown signal, the resistance of the pipeline between the exhaust port of the compressor and the input end of the liquid storage tank is increased, so that a pressure difference is formed on the pipeline between the exhaust port of the compressor and the return air port, so that the mixture of refrigerant and refrigeration oil accumulated in the internal threaded copper tubes of each heat exchanger migrates to the liquid storage tank under the action of the pressure difference, thereby removing the mixture of refrigerant and refrigeration oil accumulated in the internal threaded copper tubes and reducing the adverse effects of refrigerant migration on the start-up of the compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a heat pump unit in the prior art;

[0027] Figure 2 A schematic structural diagram of a heat pump unit in one embodiment of the present invention;

[0028] Figure 3 A schematic structural diagram of a heat pump unit in another embodiment of the present invention;

[0029] Figure 4 Schematic diagram of the structure of the liquid storage tank of a heat pump unit in one embodiment of the present invention.

[0030] In the picture:

[0031] 10. Compressor; 11. Air return port; 12. Exhaust port;

[0032] 20. Four-way valve; 21. First port; 22. Second port; 23. Third port; 24. Fourth port;

[0033] 30. First heat exchanger;

[0034] 40. Throttling element;

[0035] 50. Second heat exchanger;

[0036] 60. Liquid storage tank; 61. Input end; 62. Output end; C. Accommodation chamber;

[0037] 71. First control valve; 72. Second control valve; 73. Third control valve;

[0038] 81. First heating component; 82. Second heating component. DETAILED DESCRIPTION

[0039] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the accompanying drawings, but the present invention is not limited to these embodiments.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0041] It should be noted that when an element is referred to as being “fixed to” another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0042] The inventors have discovered that, in conventional heat pump units, to improve the heat exchange efficiency of the first heat exchanger 30 and the second heat exchanger 50, internally threaded copper tubes are used within the first heat exchanger 30 and / or the second heat exchanger 50 as refrigerant circulation channels. These internally threaded copper tubes have a large surface area and offer the advantage of high heat exchange efficiency. To lubricate the components in the refrigerant cycle and ensure reliable operation of the heat pump unit, refrigeration oil is also mixed with the refrigerant for lubrication. The refrigeration oil circulates along with the refrigerant through the compressor 10, the first heat exchanger 30, the throttling element 40, and the second heat exchanger 50.

[0043] However, because the refrigerant flow channel formed by the internally threaded copper tube is uneven, refrigerant and refrigeration oil easily accumulate on the inner sidewall of the internally threaded copper tube, forming a refrigerant-oil mixture. After the heat pump unit is shut down in a low-temperature environment, the large temperature difference between indoors and outdoors creates a pressure difference. Under the action of this temperature difference, the refrigerant-oil mixture accumulated in the internally threaded copper tubes of the first heat exchanger 30 and the second heat exchanger 50 migrates to the bottom of the compressor 10 under the action of this pressure difference. When the heat pump unit is restarted, the compressor 10 starts up. The refrigerant-oil mixture accumulated at the bottom of the compressor 10 prevents the compressor 10 from properly absorbing refrigerant and refrigeration oil, resulting in a series of reliability issues such as liquid hammer, insufficient lubrication, and startup loss of step in the compressor 10, affecting the normal startup and operation of the compressor 10.

[0044] In order to solve the above technical problems, the inventors thought that the boiling points of refrigerant and refrigeration oil are different, and the boiling point of refrigerant is lower than that of refrigeration oil. Therefore, before restarting the compressor 10 in a low-temperature environment, the mixture of refrigerant and refrigeration oil can be removed by heating the bottom of the compressor 10. The refrigerant with a lower boiling point is converted into a gaseous state, and the refrigeration oil with a higher boiling point remains in a liquid state. After removing the mixture of refrigerant and refrigeration oil, the compressor 10 can be started according to the normal process.

[0045] However, during the test, it was found that due to the complex structure of the bottom of the compressor 10 and the thickness of the bottom of the compressor 10, the power of the device for heating the bottom of the compressor 10 was limited, making it difficult to effectively heat the bottom of the compressor 10. A long heating time was required to completely decompose the mixture of refrigerant and refrigeration oil accumulated at the bottom of the compressor 10, which resulted in an excessively long startup time for the heat pump unit.

[0046] In order to solve the above technical problems, the present invention provides a heat pump unit that can reduce the impact of the mixture of refrigerant and refrigeration oil on the startup of the compressor 10.

[0047] like Figure 2 or Figure 3 As shown, the heat pump unit of the present invention includes a compressor 10, a first heat exchanger 30, a throttling element 40, a second heat exchanger 50, a liquid storage tank 60, a first heating component 81 and a controller; a accommodating chamber C is formed inside the liquid storage tank 60, and an input end 61 and an output end 62 connected to the accommodating chamber C are provided on the liquid storage tank 60, and the output end 62 is higher than the bottom of the accommodating chamber C.

[0048] The exhaust port 12 of the compressor 10 is connected to the input end 61 of the liquid storage tank 60 through the first heat exchanger 30, the throttling element 40 and the second heat exchanger 50 in sequence, the output end 62 of the liquid storage tank 60 is connected to the return air port 11 of the compressor 10, and the first heating component 81 is arranged on the liquid storage tank 60; the controller is electrically connected to the compressor 10 and the first heating component 81 respectively; wherein, the controller can be an independent controller or the original controller of the heat pump unit.

[0049] The controller is used to control the first heating component 81 to heat the liquid storage tank 60 after receiving the power-on signal, and to control the compressor 10 to start after heating the liquid storage tank 60. The signal received by the controller can be sent by the user or by a timing device in the heat pump unit.

[0050] When the heat pump unit is shut down in a low-temperature environment, the mixture of refrigerant and refrigeration oil accumulated in the internal threaded copper tubes of the first heat exchanger 30 and / or the second heat exchanger 50 migrates toward the return air port 11 of the compressor 10 under the action of the temperature difference. When the mixture of refrigerant and refrigeration oil passes through the liquid storage tank 60, since the output end 62 of the liquid storage tank 60 is higher than the bottom of the accommodating chamber C formed therein, the mixture of refrigerant and refrigeration oil is retained in the accommodating chamber C; during the next startup process, the controller controls the first heating component 81 to heat the liquid storage tank 60 after receiving the startup signal. During the heating process, the refrigerant in the mixture of refrigerant and refrigeration oil is converted into gas, while the refrigeration oil remains in liquid form, thereby separating the refrigerant and refrigeration oil to remove the mixture of refrigerant and refrigeration oil that may affect the normal startup and operation of the compressor; then, the controller controls the compressor 10 to start up, and the heat pump host can be started according to the normal startup process.

[0051] The heat pump host may operate in different ambient temperatures. When the ambient temperature is high, the liquid storage tank 60 needs to be heated for a shorter time or even no heating is required. When the ambient temperature is low, the liquid storage tank 60 needs to be heated for a longer time to completely remove the mixture of refrigerant and refrigeration oil. Therefore, in order to adapt to different ambient temperatures, so that the compressor of the heat pump unit can start normally, the startup time of the heat pump unit is also shortened. In a preferred embodiment, an ambient temperature sensor is also included, and the ambient temperature sensor is electrically connected to the controller. The controller is also used to obtain the ambient temperature through the ambient temperature sensor, and control the heating time of the first heating component 81 to the liquid storage tank 60 according to the pre-established correspondence between the ambient temperature and the heating time.

[0052] In a specific embodiment, if the ambient temperature is lower than the first preset temperature threshold, the controller controls the first heating component 81 to heat the liquid storage tank 60 for a first set time; if the ambient temperature is greater than the first preset temperature threshold and lower than the second preset temperature threshold, the controller controls the first heating component 81 to heat the liquid storage tank 60 for a second set time; if the ambient temperature is greater than the second preset temperature threshold and lower than the third preset temperature threshold, the controller controls the first heating component 81 to heat the liquid storage tank 60 for a third set time; wherein, the first preset temperature threshold < the second temperature threshold < the third temperature threshold, the first set heating time > the second set heating time > the third set heating time.

[0053] In other embodiments, a relationship between ambient temperature and heating time can be established in advance through experiments. When the heat pump unit is started, after obtaining the ambient temperature, the time required to heat the liquid storage tank 60 at the current ambient temperature can be calculated through the relationship.

[0054] The inventors have found that if the resistance of the pipeline between the exhaust port 12 and the return air port 11 of the compressor 10 increases, a large pressure difference will be formed between the exhaust port 12 and the return air port 11 of the compressor 10. Under the action of this pressure difference, the mixture of refrigerant and refrigeration oil accumulated in the internal threaded copper tube of the first heat exchanger 30 and / or the second heat exchanger 50 will quickly migrate toward the return air port 11 of the compressor 10, and the migration speed is much faster than the migration that occurs when the heat pump unit is shut down in a low-temperature environment. The mixture of refrigerant and refrigeration oil is retained in the liquid storage tank 60 when passing through the liquid storage tank 60, thereby reducing the accumulation of the mixture of refrigerant and refrigeration oil in the internal threaded copper tube, and reducing the adverse effects of refrigerant migration on the start-up of the compressor 10.

[0055] In order to increase the resistance of the pipeline between the exhaust port 12 and the return air port 11 of the compressor 10, as shown in FIG. Figure 2 As shown, in a preferred embodiment, the controller is also electrically connected to the throttling element 40; the controller is also used to control the throttling element 40 to adjust to the minimum opening after receiving the shutdown signal, and to control the compressor 10 to stop running after the throttling element 40 is adjusted to the minimum opening.

[0056] In this embodiment, upon receiving a shutdown signal, the controller adjusts the opening of the throttling element 40 to its minimum opening, thereby increasing the resistance of the pipeline between the exhaust port 12 and the return air port 11 of the compressor 10. The refrigerant and refrigeration oil mixture accumulated in the internally threaded copper tubes of the first heat exchanger 30 and / or the second heat exchanger 50 rapidly migrates toward the return air port 11 of the compressor 10, and is retained in the liquid storage tank 60 upon passing through the liquid storage tank 60. Subsequently, the controller controls the compressor 10 to reduce its frequency to 0 Hz, thereby stopping the compressor 10. In this embodiment, the throttling element 40 of the heat pump unit itself is utilized to create resistance in the pipeline between the exhaust port 12 and the return air port 11 of the compressor 10, eliminating the need for additional components and resulting in lower costs.

[0057] In a preferred embodiment, after controlling the throttle element 40 to be adjusted to its minimum opening and before controlling the compressor 10 to stop operating, the controller is further configured to control the compressor 10 to increase its frequency. In this embodiment, upon receiving a shutdown signal, the controller first adjusts the throttle element 40 to its minimum opening, then increases the frequency of the compressor 10, and finally stops the compressor 10. After the throttle element 40 is adjusted to its minimum opening, a large pressure differential is formed between the exhaust port 12 and the return port 11 of the compressor 10. After the compressor 10 increases its frequency, the pressure differential between the exhaust port 12 and the return port 11 of the compressor 10 further increases, thereby enabling the refrigerant and refrigeration oil mixture accumulated in the internally threaded copper tube to migrate more quickly and thoroughly into the liquid storage tank 60.

[0058] In order to increase the resistance of the pipeline between the exhaust port 12 and the return air port 11 of the compressor 10, in another optional embodiment, as shown in FIG. Figure 3 As shown, it also includes a first control valve 71, which is arranged between the exhaust port 12 of the compressor 10 and the first heat exchanger 30, and the first control valve 71 is electrically connected to the controller; the controller is also used to control the first control valve 71 to close after receiving a shutdown signal, and to control the compressor 10 to stop running after the first control valve 71 is closed.

[0059] In this embodiment, after receiving the shutdown signal, the first control valve 71 is closed to increase the resistance of the pipeline between the exhaust port 12 and the return air port 11 of the compressor 10, and the mixture of refrigerant and refrigeration oil accumulated in the internal threaded copper tube of the first heat exchanger 30 and / or the second heat exchanger 50 will quickly migrate toward the return air port 11 of the compressor 10, and the mixture of refrigerant and refrigeration oil will be retained in the liquid storage tank 60 when passing through the liquid storage tank 60; then, the controller controls the compressor 10 to reduce the frequency to 0 Hz, that is, controls the compressor 10 to stop running.

[0060] In the process of migrating the refrigerant and refrigeration oil mixture in the internal threaded copper tube to the liquid storage tank 60, the refrigerant and refrigeration oil mixture splashes under the action of the pressure difference, causing part of the refrigerant and refrigeration oil mixture to enter the bottom of the compressor 10 through the output end 62 of the liquid storage tank 60, thereby affecting the normal startup and operation of the compressor 10; in addition, when the refrigerant and refrigeration oil mixture migrating to the liquid storage tank 60 is large, part of the refrigerant and refrigeration oil mixture may overflow from the output end 62 of the liquid storage tank 60 to the bottom of the compressor 10, also affecting the normal startup and operation of the compressor 10; therefore, in order to solve the above technical problems, in a preferred embodiment, as Figure 2 or Figure 3 As shown, it also includes a second heating component 82 arranged at the bottom of the compressor 10, and the second heating component 82 is electrically connected to the controller; the controller is also used to control the second heating component 82 to heat the bottom of the compressor 10 when heating the liquid storage tank 60.

[0061] In this embodiment, after receiving the power-on signal, the controller controls the first heating component 81 and the second heating component 82 to heat the liquid storage tank 60 and the bottom of the compressor 10 respectively, so as to remove the mixture of refrigerant and refrigeration oil accumulated at the bottom of the compressor 10 and the liquid storage tank 60, and prevent the mixture of refrigerant and refrigeration oil from affecting the normal startup and operation of the compressor 10.

[0062] After the heat pump unit stops running, the mixture of refrigerant and refrigeration oil in the liquid storage tank 60 may still migrate to the bottom of the compressor 10 under the action of the pressure difference formed by the temperature difference; therefore, it also includes a third control valve 73 arranged between the input end 61 of the liquid storage tank 60 and the second heat exchanger 50, and the third control valve 73 is electrically connected to the controller; the controller 90 is used to control the third control valve 73 to close after the compressor 10 stops running, and to control the second control valve 72 to open after the liquid storage tank 60 is heated and before the compressor 10 is started.

[0063] In this embodiment, after the compressor 10 stops running, the third control valve 73 is closed to prevent the mixture of refrigerant and refrigeration oil from continuing to migrate to the bottom of the compressor 10 when the heat pump unit is shut down; during the startup process, after heating the liquid storage tank 60, the third control valve 73 is opened first, and then the compressor 10 is started, so that the compressor 10 can start normally.

[0064] During the heating process of the liquid storage tank 60, heat will be dissipated from the input end 61 of the liquid storage tank 60, thereby reducing the heat utilization rate and increasing the required heating time. Therefore, in a preferred embodiment, a third control valve 73 is further provided between the input end 61 of the liquid storage tank 60 and the second heat exchanger 50. The third control valve 73 is electrically connected to the controller. The controller is further configured to control the third control valve 73 to close after the compressor 10 stops operating, and to control the third control valve 73 to open after the liquid storage tank 60 is heated and before the compressor 10 is started. Specifically, the third control valve 73 can be controlled to close before the liquid storage tank 60 is heated.

[0065] In this embodiment, after the compressor 10 stops running, the third control valve 73 is controlled to close, and with the cooperation of the second control valve 72 and the third control valve 73, the mixture of refrigerant and refrigeration oil is sealed in the liquid storage tank 60; then, during the startup of the heat pump unit, after the heating of the liquid storage tank 60 is completed, the second control valve 72 and the third control valve 73 are opened first, and then the compressor 10 is started, so that the compressor 10 that is started subsequently can start normally.

[0066] In other embodiments, a heat insulation layer may be provided outside the liquid storage tank 60 and the first heating assembly 81 to improve the heating efficiency of the liquid storage tank 60 .

[0067] In order to reduce the noise generated by the refrigerant flow, in a preferred embodiment, Figure 4 As shown, the accommodating chamber C formed in the liquid storage tank 60 is columnar, and the input end 61 and the output end 62 are respectively arranged at the two ends of the accommodating chamber, thereby, the liquid storage tank 60 forms a muffler structure; during the normal operation of the heat pump unit, the refrigerant enters the accommodating chamber C from the input end 61 of the liquid storage tank 60, and the flow space of the refrigerant is expanded, and then is output from the output end 62, and the flow space of the refrigerant is contracted; in the process of expansion and contraction of the flow space, the vibration of the refrigerant is absorbed, thereby reducing the noise generated by the flow of the refrigerant, thereby reducing the noise generated during the operation of the heat pump unit; and during the shutdown of the heat pump unit, the accommodating chamber C is used to accommodate a mixture of refrigerant and refrigeration oil.

[0068] In a preferred embodiment, the length of the accommodating chamber C is 8-10 times its diameter, so that the vibration frequency of the refrigerant matches the resonance frequency of the accommodating chamber C, thereby further improving the noise reduction effect of the accommodating chamber C.

[0069] In a preferred embodiment, Figure 2 or Figure 3As shown, in order to realize the switching of heating and cooling modes of the heat pump unit, a four-way valve 20 is also included. The four-way valve 20 is provided with a first interface 21, a second interface 22, a third interface 23 and a fourth interface 24. The exhaust port 12 of the compressor 10 is connected to the first interface 21 of the four-way valve 20, the input end 61 of the liquid storage tank 60 is connected to the second interface 22 of the four-way valve 20, and the third interface 23 of the four-way valve 20 is connected to the fourth interface 24 through the second heat exchanger 50, the throttling element 40 and the first heat exchanger 30 in sequence.

[0070] The four-way valve 20 can switch between a first state and a second state. When the four-way valve 20 is in the first state, the first interface 21 is connected to the third interface 23, and the second interface 22 is connected to the fourth interface 24. At this time, the refrigerant output through the exhaust port 12 of the compressor 10 passes through the second heat exchanger 50, the throttling element 40, the first heat exchanger 30 in sequence, and finally returns to the return air port 11 of the compressor 10. The refrigerant absorbs heat in the first heat exchanger 30 and releases heat in the second heat exchanger 50. That is, the first heat exchanger 30 acts as an evaporator and the second heat exchanger 50 acts as a condenser. The heat pump The unit is currently in cooling mode; when the four-way valve 20 is in the second state, the first interface 21 and the fourth interface 24 are connected, and the second interface 22 and the third interface 23 are connected. At this time, the refrigerant output through the exhaust port 12 of the compressor 10 passes through the first heat exchanger 30, the throttling element 40, and the second heat exchanger 50 in sequence, and finally returns to the return air port 11 of the compressor 10. The refrigerant releases heat in the first heat exchanger 30 and absorbs heat in the second heat exchanger 50, that is, the first heat exchanger 30 acts as a condenser and the second heat exchanger 50 acts as an evaporator. The heat pump unit is currently in heating mode.

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] 1. A liquid storage tank for containing a mixture of refrigerant and refrigeration oil is set at the return air port of the compressor. After the heat pump unit receives the start-up signal, it heats the liquid storage tank to evaporate the refrigerant in the liquid storage tank and separate it from the refrigeration oil mixture. Then the compressor is started, thereby reducing the impact of the refrigerant and refrigeration oil mixture on the startup and operation of the compressor;

[0073] 2. After receiving the power-on signal, the ambient temperature is obtained and the heating time of the liquid storage tank is determined by the correspondence between the preset ambient temperature and the heating time. In this way, the startup time of the heat pump unit can be shortened while ensuring that the refrigerant and the refrigeration oil can be completely separated;

[0074] 3. After the heat pump unit receives the shutdown signal, the resistance of the pipeline between the exhaust port of the compressor and the input end of the liquid storage tank is increased, so that a pressure difference is formed on the pipeline between the exhaust port of the compressor and the return air port, so that the mixture of refrigerant and refrigeration oil accumulated in the internal threaded copper tubes of each heat exchanger migrates to the liquid storage tank under the action of the pressure difference, thereby removing the mixture of refrigerant and refrigeration oil accumulated in the internal threaded copper tubes and reducing the adverse effects of refrigerant migration on the start-up of the compressor.

[0075] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A heat pump unit, characterized in that: The invention comprises a compressor (10), a first heat exchanger (30), a throttling element (40), a second heat exchanger (50), a liquid storage tank (60), a first heating assembly (81), and a controller; a receiving chamber (C) is formed inside the liquid storage tank (60); an input end (61) and an output end (62) communicating with the receiving chamber (C) are provided on the liquid storage tank (60); the output end (62) is higher than the bottom of the receiving chamber (C); The exhaust port (12) of the compressor (10) is connected to the input end (61) of the liquid storage tank (60) through the first heat exchanger (30), the throttling element (40), and the second heat exchanger (50) in sequence; the output end (62) of the liquid storage tank (60) is connected to the return air port (11) of the compressor (10); the first heating component (81) is arranged on the liquid storage tank (60); and the controller is electrically connected to the compressor (10) and the first heating component (81); The controller is used to control the first heating component (81) to heat the liquid storage tank (60) after receiving a power-on signal, and is used to control the compressor (10) to start after heating the liquid storage tank (60); The controller is also electrically connected to the throttling element (40); The controller is also used to control the throttling element (40) to be adjusted to a minimum opening after receiving a shutdown signal, and to control the compressor (10) to stop running after the throttling element (40) is adjusted to the minimum opening.

2. The heat pump unit according to claim 1, characterized in that: Also included is an ambient temperature sensor, the ambient temperature sensor being electrically connected to the controller; The controller is further configured to obtain the ambient temperature via the ambient temperature sensor, and control the duration for which the first heating component (81) heats the liquid storage tank (60) based on the obtained ambient temperature and a previously established correspondence between the ambient temperature and the heating duration.

3. The heat pump unit according to claim 1, characterized in that: After controlling the throttling element (40) to be adjusted to a minimum opening and before controlling the compressor (10) to stop running, the controller is further used to control the compressor (10) to increase the frequency.

4. The heat pump unit according to claim 1, characterized in that: The system further comprises a first control valve (71), the first control valve (71) being arranged between the exhaust port (12) of the compressor (10) and the first heat exchanger (30), and the first control valve (71) being electrically connected to the controller; The controller is further configured to control the first control valve (71) to close after receiving a shutdown signal, and to control the compressor (10) to stop running after the first control valve (71) is closed.

5. The heat pump unit according to claim 1, characterized in that: It also includes a second heating component (82) disposed at the bottom of the compressor (10), and the second heating component (82) is electrically connected to the controller; The controller is further configured to control the second heating component (82) to heat the bottom of the compressor (10) when heating the liquid storage tank (60).

6. The heat pump unit according to any one of claims 1 to 5, characterized in that: It also includes a second control valve (72) disposed between the output end (62) of the liquid storage tank (60) and the air return port (11) of the compressor (10), wherein the second control valve (72) is electrically connected to the controller; The controller is further configured to control the second control valve (72) to close after the compressor (10) stops running, and to control the second control valve (72) to open after the liquid storage tank (60) is heated and before the compressor (10) is started.

7. The heat pump unit according to claim 6, characterized in that: It also includes a third control valve (73) disposed between the input end (61) of the liquid storage tank (60) and the second heat exchanger (50), wherein the third control valve (73) is electrically connected to the controller; The controller is further configured to control the third control valve (73) to close after the compressor (10) stops running, and to control the third control valve (73) to open after the liquid storage tank (60) is heated and before the compressor (10) is started.

8. The heat pump unit according to any one of claims 1 to 5, characterized in that: The accommodating cavity (C) formed in the liquid storage tank (60) is columnar, and the input end (61) and the output end (62) are respectively arranged at two ends of the accommodating cavity (C).

9. The heat pump unit according to claim 8, characterized in that: The length of the accommodating cavity (C) is 8-10 times its diameter.

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