A heat pump unit

Abstract

This invention discloses a heat pump unit, comprising: a compressor, a first water-cooled heat exchanger, and a first throttling device; an air-side heat exchanger connected to a first pipeline; a second water-cooled heat exchanger connected in parallel with a second pipeline; a detection component; in a first cooling mode, the first pipeline is disconnected and the second pipeline is connected; the controller is configured to: before the unit enters the first cooling mode, control the compressor, the first water-cooled heat exchanger, the first throttling device, and the air-side heat exchanger to form a flow path; control the opening of the first throttling device and the start / stop of the fan based on a target superheat range and a target exhaust temperature range; when the first throttling device's operating time, exhaust temperature, and suction pressure reach a first preset condition, control the compressor and fan to stop; when the high-pressure and suction pressure difference meet a preset switching condition, disconnect the first pipeline and connect the second pipeline. The unit of this invention can release unused stored refrigerant into the system, ensuring reliable system operation.

Description

Technical Field

[0001] This invention relates to the field of heat pump technology, and more specifically to an improvement in the structure of a heat pump unit. Background Technology

[0002] While air-cooled heat pump chillers are flexible in application and suitable for most outdoor occasions, their energy efficiency is lower than that of water-cooled chillers under cooling conditions. Water-cooled heat pump chillers, on the other hand, have high cooling efficiency, but require an additional heat source when heating, thus limiting their application scenarios.

[0003] To simultaneously improve the cooling and heating energy efficiency of air-cooled heat pump chillers, some manufacturers have begun to introduce dual-source heat pump chillers, which combine water cooling and air cooling. While ensuring heating performance, the unit improves its cooling energy efficiency by replacing air cooling heat exchange with water cooling heat exchange during cooling operation, thus ensuring higher energy efficiency in cooling mode.

[0004] Unlike traditional multi-split heat pump units, which require determining the final refrigerant charge based on the type, number, and length of the connecting pipes of the indoor units (generally requiring a larger refrigerant and lubricating oil charge), dual-source heat pump chillers integrate both the evaporator and condenser inside the outdoor unit. The heat exchanger has a fixed internal volume, and the connecting pipes between different components inside the unit are short. Therefore, the refrigerant charge for the entire unit is less and a fixed value.

[0005] When a dual-source heat pump chiller is operating in different modes, because its total refrigerant and lubricating oil charge is relatively small, if improper distribution causes some refrigerant and lubricating oil to be stored in unused heat exchangers, it may also cause problems such as high exhaust temperature, poor energy efficiency, and compressor wear due to lack of refrigerant or lubricating oil.

[0006] To avoid the aforementioned problems, some manufacturers will add extra refrigerant and lubricating oil. However, adding too much refrigerant and lubricating oil will lead to poor operating efficiency of the entire unit. At the same time, if there is too much refrigerant in the operating system, it will also cause the unit to continuously close the main throttling device, i.e., the electronic expansion valve, resulting in excessively high exhaust pressure, which will affect the reliability of the entire unit. Therefore, how to ensure that the limited refrigerant and lubricating oil are always kept in the system required for operation under the appropriate refrigerant and lubricating oil charge is an important problem that needs to be solved. Summary of the Invention

[0007] In response to the aforementioned technical problems mentioned in the background section, a dual-source heat pump unit is proposed, which can release unused stored refrigerant into the system during cooling operation, ensuring the reliable and stable operation of the entire system.

[0008] In some embodiments of this application, a heat pump unit is provided, including:

[0009] The refrigerant circuit is formed by connecting a compressor, a first water-cooled heat exchanger, a second heat exchanger group, a first throttling device, a four-way valve, and a gas-liquid separator.

[0010] The second heat exchanger assembly includes:

[0011] An air-side heat exchanger is connected to the first pipeline between the four-way valve and the first water-cooled heat exchanger;

[0012] A fan is installed on the air-side heat exchanger side to drive the airflow in the air-side heat exchanger.

[0013] The second water-cooled heat exchanger is connected in parallel with the air-side heat exchanger through the second pipeline;

[0014] Control valves are installed on the first and second pipelines;

[0015] The detection component is used to detect the temperature, exhaust temperature, high pressure, and suction pressure of the air-side heat exchanger.

[0016] The heat pump unit has a first cooling mode. When it is in the first cooling mode, the control valve controls the first pipeline to disconnect and the second pipeline to open.

[0017] The controller is configured to:

[0018] The superheat of the air-side heat exchanger is obtained based on the air-side heat exchanger temperature and high pressure detected by the detection component.

[0019] When the heat pump unit is in the first cooling mode, the control valve is used to disconnect the first pipeline and open the second pipeline.

[0020] Before the heat pump unit enters the first cooling mode, the compressor is controlled to run and the control valve is controlled to open the first pipeline to form a first refrigerant flow path between the compressor, the first water-cooled heat exchanger, the first throttling device, and the air-side heat exchanger.

[0021] The opening degree of the first throttling device and the start and stop of the fan are controlled with the target superheat range and target exhaust temperature range pre-stored in the controller, so that the refrigerant in the air-side heat exchanger is converted into a high-temperature and high-pressure superheated gas.

[0022] When the first throttling device's operating time, exhaust temperature, and intake pressure reach the first preset conditions, the compressor and fan are controlled to stop running, and the first throttling device is controlled to maintain the first preset opening so that the high-temperature and high-pressure superheated gas and internal lubricating oil in the air-side heat exchanger are removed from the air-side heat exchanger.

[0023] When the difference between the high pressure and the intake pressure meets the preset switching conditions, the control valve disconnects the first pipeline and connects the second pipeline.

[0024] The above embodiments have the following advantages and effects:

[0025] In this embodiment, before the first cooling mode is pre-activated, the first pipeline is opened to form a first refrigerant flow path between the first water-cooled heat exchanger and the compressor on the air side. When the refrigerant flows in the first refrigerant flow path, the refrigerant in the air side heat exchanger is converted into a high-temperature, high-pressure superheated gas by controlling the first throttling device and the fan. By controlling the compressor to stop, the high-temperature, high-pressure superheated gas stored in the air side heat exchanger is removed from the air side heat exchanger by utilizing the pressure difference. Since the first cooling mode utilizes the first water-cooled heat exchanger, this ensures that the refrigerant is removed before the first cooling mode is activated. The refrigerant and lubricating oil of the entire unit will not be stored in the air side heat exchanger, which does not participate in the circulation. This ensures that the refrigerant and lubricating oil in the unit are fully used for the first cooling mode, avoiding a series of problems such as high system exhaust temperature, low suction pressure, poor energy efficiency, and compressor wear caused by insufficient refrigerant and compressor lubricating oil. This ensures that the entire unit always operates in the optimal control state, improving the unit's performance and operational stability.

[0026] In some embodiments of this application, the controller is configured to: after the first throttling device has been running at an initial first opening for a preset time, adjust the opening of the first throttling device and the start / stop state of the fan according to a first adjustment rule so that the superheat of the air-side heat exchanger and the exhaust temperature are close to the target superheat range and the target exhaust temperature range.

[0027] The above embodiments have the following advantages and effects:

[0028] After the unit has been running for a preset time, the controller can obtain the superheat and exhaust temperature of the air-side heat exchanger. The controller has a first adjustment rule for controlling the opening of the first throttling device and the start / stop of the fan based on the superheat and exhaust temperature of the air-side heat exchanger. During adjustment, the controller can adjust and control the opening of the first throttling device and the start / stop of the fan according to the first adjustment rule based on the different superheat and exhaust temperature values ​​of the air-side heat exchanger, so that the actual superheat and exhaust temperature of the air-side heat exchanger infinitely approach the target superheat range and the target exhaust temperature range.

[0029] In some embodiments of this application, the first adjustment rule includes:

[0030] First rule: When the superheat of the air-side heat exchanger is within the target superheat range and the exhaust temperature reaches the upper limit of the set upper limit temperature, control the first throttling device to increase the opening and control the fan to start.

[0031] Second rule: When the superheat of the air-side heat exchanger is within the target superheat range and the exhaust temperature reaches the upper limit of the target exhaust temperature range, control the first throttling device to increase its opening and control the fan to stop.

[0032] Third rule: When the air-side superheat is within the target superheat range and the exhaust temperature is within the target exhaust temperature range, control the first throttling device to maintain the first opening and control the fan to stop;

[0033] Fourth rule: When the superheat of the air-side heat exchanger is within the target superheat range and the exhaust temperature reaches the lower limit of the target exhaust temperature range, control the first throttling device to reduce its opening and control the fan to stop.

[0034] Fifth rule: When the superheat of the air-side heat exchanger reaches the lower limit of the target superheat range, control the first throttling device to increase its opening and control the fan to stop.

[0035] The priority of the first rule, the second rule, the third rule, the fourth rule, and the fifth rule decreases in that order.

[0036] The set upper limit temperature is greater than the upper limit of the target exhaust temperature range.

[0037] The above embodiments have the following advantages and effects:

[0038] By setting the first to fifth rules, when the controller obtains the superheat and exhaust temperature of the air-side heat exchanger, it can precisely control the opening of the first throttling device and the start and stop of the fan according to the above five rules, ensuring that the refrigerant in the air-side heat exchanger can be converted into a superheated gaseous state.

[0039] In some embodiments of this application, the controller is configured to: after each preset time period, sequentially determine the rules that the superheat of the air-side heat exchanger and the exhaust temperature meet according to the first to the fifth rules, and control the opening degree of the first throttling device and the start and stop of the fan according to the rules they meet.

[0040] The above embodiments have the following advantages and effects:

[0041] Every preset time interval, the controller acquires the actual superheat and exhaust temperature of the air-side heat exchanger. Then, it determines which rule from the first to the fifth rule the superheat and exhaust temperature of the air-side heat exchanger meet. The controller then controls the opening of the first throttling device and the start / stop of the fan according to the rule that the air-side heat exchanger meets, so as to ensure the state of the refrigerant in the air-side heat exchanger.

[0042] In some embodiments of this application, the first preset condition includes at least the following:

[0043] The first throttling device has reached the upper limit of the set time threshold during its operation.

[0044] Alternatively, the exhaust temperature reaches the upper limit of the exhaust temperature threshold.

[0045] Alternatively, the inhalation pressure reaches the lower limit of the inhalation pressure threshold.

[0046] The above embodiments have the following advantages and effects:

[0047] By detecting the running time, exhaust temperature, or intake pressure during the startup phase, it is possible to accurately determine whether to proceed to the switching preparation phase.

[0048] In some embodiments of this application, the preset switching conditions include:

[0049] First switching condition: The difference between the high pressure and the inhalation pressure reaches the lower limit of the first switching threshold;

[0050] Alternatively, the second switching condition is: the difference between the high pressure and the inhalation pressure reaches the lower limit of the second switching threshold and the duration is greater than the preset switching time.

[0051] The above embodiments have the following advantages and effects:

[0052] When the difference between the compressor's high pressure and suction pressure is small, it can be determined that the refrigerant in the air-side heat exchanger has been almost completely removed.

[0053] When the difference between the high-pressure and suction pressure is detected to be slightly large but has persisted for the preset switching time, it indicates that the pressure has stabilized and the refrigerant in the air-side heat exchanger has been largely removed.

[0054] Therefore, when the controller detects, if it finds that either the first switching condition or the second switching condition is met, it can control the first pipeline to disconnect and the second pipeline to open, so that the unit enters the first cooling mode.

[0055] In some embodiments of this application, the heat pump unit has a second cooling mode. When the heat pump unit is in the second cooling mode, the control valve controls the first pipeline to be open and the second pipeline to be closed, forming a second cooling cycle loop between the compressor, the four-way valve, the air-side heat exchanger, the first water-cooled heat exchanger and the gas-liquid separator.

[0056] The controller is configured to:

[0057] Before the heat pump unit enters the second cooling mode, the compressor is controlled to run and the control valve is controlled to open the second pipeline to form a second refrigerant flow path between the compressor, the first water-cooled heat exchanger, and the second water-cooled heat exchanger.

[0058] The opening degree of the first throttling device and the start and stop of the water pump on the side of the second water-cooled heat exchanger are controlled with the target superheat and target exhaust temperature pre-stored in the controller, so that the refrigerant in the second water-cooled heat exchanger is converted into a high-temperature and high-pressure superheated gas.

[0059] When the first throttling device's operating time, exhaust temperature, and intake pressure meet the second preset conditions, the compressor is controlled to stop running, the water pump on the second water-cooled heat exchanger side is controlled to stop running, and the first throttling device is controlled to maintain the first preset opening so that the high-temperature and high-pressure superheated gas and internal lubricating oil in the second water-cooled heat exchanger are removed from the second water-cooled heat exchanger.

[0060] When the difference between the high pressure and the intake pressure meets the preset switching conditions, the control valve opens the first pipeline and disconnects the second pipeline.

[0061] The above embodiments have the following advantages and effects:

[0062] In this embodiment, before the second cooling mode is pre-activated, the second pipeline is first opened to form a second refrigerant flow path between the second water-cooled heat exchanger, the first water-cooled heat exchanger, and the compressor. When the refrigerant flows in the second refrigerant flow path, the refrigerant in the second water-cooled heat exchanger is converted into a high-temperature, high-pressure superheated gas by controlling the first throttling device and the water pump on the second water-cooled heat exchanger side. By controlling the compressor to stop, the high-temperature, high-pressure superheated gas stored in the second water-cooled heat exchanger is removed from the second water-cooled heat exchanger by utilizing the pressure difference. Since the air-side heat exchanger is used when the second cooling mode is running, it can be ensured that the refrigerant and lubricating oil of the entire unit will not be stored in the second water-cooled heat exchanger, which does not participate in the circulation, when the second cooling mode is running. This ensures that the refrigerant and lubricating oil in the unit are fully used for the second cooling mode, avoiding a series of problems such as high system exhaust temperature, low suction pressure, poor energy efficiency, and compressor wear caused by insufficient refrigerant and compressor lubricating oil. This ensures that the entire unit always operates in the optimal control state, improving the performance and operational stability of the unit.

[0063] In some embodiments of this application, a subcooler is included, configured as follows:

[0064] When the heat pump unit is in the first cooling mode, the subcooler is connected between the second water-cooled heat exchanger and the first water-cooled heat exchanger to cool the refrigerant flowing out of the second water-cooled heat exchanger.

[0065] When the heat pump unit is in heating mode, the subcooler is connected between the first water-cooled heat exchanger and the air-side heat exchanger to cool the refrigerant flowing out of the first water-cooled heat exchanger.

[0066] The above embodiments have the following advantages and effects:

[0067] By installing a subcooler in the heat pump unit, when the unit is in the first cooling mode, the refrigerant flowing out of the second water-cooled heat exchanger can be further cooled by the subcooler, which further reduces the temperature of the refrigerant and achieves high-efficiency cooling.

[0068] When the unit is in heating mode, the refrigerant in the first water-cooled heat exchanger is further cooled by the subcooler to reduce the refrigerant temperature and achieve high-efficiency heating.

[0069] In some embodiments of this application, the subcooler is configured with a subcooler refrigerant flow path through its interior, having an inlet and an outlet.

[0070] The heat pump unit includes: a main connecting pipe, which is connected to the first pipe and the second pipe;

[0071] A first connecting pipe is connected to the main connecting pipe and the inlet, and a first control valve is provided on the first connecting pipe;

[0072] A second connecting pipe is connected between the first water-cooled heat exchanger and the outlet section, and a second control valve is provided on the second connecting pipe.

[0073] The above embodiments have the following advantages and effects:

[0074] By setting up a first connecting pipeline and a first control valve on the first connecting pipeline, a second connecting pipeline and a second control valve, and a control valve for switching between the first pipeline and the second pipeline, the refrigerant can be restricted to circulate between the compressor, the four-way valve, the first water-cooled heat exchanger and the second water-cooled heat exchanger when the unit is in the first cooling operation mode, so as to achieve a high-efficiency cooling effect.

[0075] In some embodiments of this application, when the heat pump unit is in heating mode, a heating circulation loop is formed between the compressor, the first water-cooled heat exchanger, the air-side heat exchanger, the four-way valve, and the gas-liquid separator.

[0076] The control valve includes:

[0077] The first valve is used to control the opening and closing of the first pipeline;

[0078] The second valve is used to control the opening and closing of the second pipeline;

[0079] During refrigeration operation, the first valve is closed and the second valve is open.

[0080] When heating is in operation, the first valve is open and the second valve is closed.

[0081] The above embodiments have the following advantages and effects:

[0082] By coordinating the first and second control valves, the on / off state of the first and second pipelines can be controlled, thereby enabling the selection of the air-side heat exchanger and the second water-cooled heat exchanger participating in the circulation, ensuring the high energy efficiency of the heat pump unit in cooling or heating.

[0083] Other features and advantages of the present invention will become clearer after reading the detailed embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0084] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0085] Figure 1 This is a schematic diagram of one embodiment of a heat pump unit according to the embodiments;

[0086] Figure 2 This is a schematic diagram of refrigerant flow in a first cooling mode according to one embodiment of the heat pump unit.

[0087] Figure 3 This is a schematic diagram of the refrigerant flow direction in heating mode according to one embodiment of the heat pump unit;

[0088] Figure 4 This is a schematic diagram of one embodiment of a heat pump unit according to the present invention.

[0089] Figure 5 This is a schematic diagram of the refrigerant flow direction in the first refrigeration cycle mode of one embodiment of the heat pump unit according to the example;

[0090] Figure 6 This is a schematic diagram of the refrigerant flow in the first refrigeration cycle mode of another embodiment of the heat pump unit according to the present invention.

[0091] Figure 7 This is a schematic diagram of the refrigerant flow direction in heating cycle mode according to one embodiment of a heat pump unit;

[0092] Figure 8 This is a schematic diagram of the refrigerant flow in heating cycle mode according to another embodiment of the heat pump unit;

[0093] Figure 9 This is a schematic diagram of the refrigerant flow path and branch flow path of the subcooler of the heat pump unit according to an embodiment;

[0094] Figure 10 This is a schematic diagram of the refrigerant flow direction of the heat pump unit according to the embodiment when it is in the second cooling mode;

[0095] Figure 11 This is a control flowchart of the heat pump unit according to an embodiment when it is in the first cooling mode;

[0096] Figure 12 This is a state change diagram corresponding to the first adjustment rule, the first throttling device, and the exhaust temperature of the heat pump unit according to the embodiment.

[0097] Figure 13 This is a control flowchart of the heat pump unit in the second cooling mode according to an embodiment;

[0098] Figure 14 This is a state change diagram corresponding to the second regulation rule of the heat pump unit according to the embodiment and the first throttling device and exhaust temperature.

[0099] Figure label:

[0100] Among them, 110 is the compressor; 120 is the first water-cooled heat exchanger; 130 is the four-way valve; 140 is the gas-liquid separator; 150 is the air-side heat exchanger; 160 is the second water-cooled heat exchanger; 170 is the control valve; 171 is the first valve; 172 is the second valve; 180 is the first pipeline; 181 is the branch pipeline; 190 is the second pipeline; 200 is the subcooler; 210 is the subcooler refrigerant flow path; 211 is the inlet; 212 is the outlet; 220 is the branch flow path; and 230 is the compressor. Air supply circuit; 300, main connecting pipe; 410, first connecting pipe; 411, first control valve; 420, second connecting pipe; 421, second control valve; 430, third connecting pipe; 431, third control valve; 432, high-pressure liquid storage tank; 440, fourth connecting pipe; 441, fourth control valve; 450, fifth control valve; 510, first throttling device; 520, second throttling device; 610, electrically controlled valve; 620, first check valve; 630, second check valve. Detailed Implementation

[0101] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0102] In some embodiments of this application, a heat pump unit is proposed, with reference to Figure 1 As shown, it includes:

[0103] The refrigerant circuit is formed by connecting the compressor 110, the first water-cooled heat exchanger 120, the second heat exchanger group, the first throttling device 510, the four-way valve 130, and the gas-liquid separator 140.

[0104] The first throttling device 510 is connected between the second heat exchanger group and the first water-cooled heat exchanger 120, and it is an electronic expansion valve.

[0105] The first water-cooled heat exchanger 120 is a first plate heat exchanger, in which refrigerant from the refrigerant circuit and water from the first hot water exchange pipeline flow. The water and refrigerant exchange heat inside the first water-cooled heat exchanger 120.

[0106] The first hot water exchange pipeline has a water pump, which is used to supply water and drive the water flow in the first hot water exchange pipeline.

[0107] The second heat exchanger assembly includes:

[0108] An air-side heat exchanger 150 is connected between a four-way valve 130 and a first water-cooled heat exchanger 120 via a first pipe 180.

[0109] The air-side heat exchanger 150 is a finned heat exchanger that can exchange heat with air.

[0110] In some embodiments of this application, a fan is provided on the air-side heat exchanger side to drive airflow and accelerate heat exchange in the air-side heat exchanger 150.

[0111] The second heat exchanger assembly includes a second water-cooled heat exchanger 160, which is arranged in parallel with the air-side heat exchanger 150 and is connected between the four-way valve 130 and the first water-cooled heat exchanger 120 via a second pipeline 190.

[0112] The second water-cooled heat exchanger 160 is a second plate heat exchanger, in which refrigerant and water flow, and the water and refrigerant exchange heat inside the second water-cooled heat exchanger 160.

[0113] The water flow in the second hot water exchange pipeline is driven by a water pump connected to the pipeline to accelerate the heat exchange between the water and the refrigerant in the second water-cooled heat exchanger.

[0114] During actual operation of the unit, the air-side heat exchanger 150 or the second water-cooled heat exchanger 160 can be selectively turned on according to the actual cooling or heating demand.

[0115] The heat pump unit has a controller that communicates with a control valve 170 to control the operation of the control valve 170. The control valve 170 is located on the first pipe 180 and the second pipe 190 and is used to control the on / off state of the first pipe 180 and the second pipe 190.

[0116] The heat pump unit has a primary cooling mode and a heating mode.

[0117] In the first cooling mode, the controller controls the first pipeline 180 to disconnect and the second pipeline 190 to open, forming a first cooling cycle loop between the compressor 110, the four-way valve 130, the second water-cooled heat exchanger 160, the first water-cooled heat exchanger 120 and the gas-liquid separator 140.

[0118] Reference Figure 2 As shown, the refrigerant flow process during the first cooling mode operation is as follows:

[0119] After exiting the compressor 110, the refrigerant enters the four-way valve 130, and then enters the second water-cooled heat exchanger 160 to exchange heat with cooling water. The high-temperature, high-pressure gaseous refrigerant becomes a medium-temperature, medium-pressure liquid refrigerant. After passing through the filter, it enters the first water-cooled heat exchanger 120. The refrigerant entering the second water-cooled heat exchanger 160 exchanges heat with the water flowing through the second hot water exchanger pipe inside. The second hot water exchanger pipe can be the user-side water pipe. The refrigerant that enters the second water-cooled heat exchanger 160 to exchange heat becomes a low-pressure, high-temperature gaseous refrigerant. Finally, it returns to the compressor 110 through the four-way valve 130 and the gas-liquid separator 140, completing one refrigerant cycle.

[0120] During the first cooling mode operation, the heat exchange between the refrigerant flowing out of the compressor 110 and the outside is carried out through the water cooling method of the first water-cooled heat exchanger 120 and the second water-cooled heat exchanger 160. The fully water-cooled heat exchange method has a higher cooling efficiency than the air heat exchange method, thus achieving high-efficiency cooling.

[0121] In heating mode, the controller controls the first pipeline 180 to be turned on and the second pipeline 190 to be turned off, forming a heating circulation loop between the compressor 110, the first water-cooled heat exchanger 120, the air-side heat exchanger 150, the four-way valve 130 and the gas-liquid separator 140.

[0122] Reference Figure 3 As shown, the refrigerant flow process during heating mode operation is as follows:

[0123] After exiting the compressor 110, the refrigerant enters the four-way valve 130, and then enters the first water-cooled heat exchanger 120 to exchange heat with the water pipes flowing through the exchanger, i.e., the user-side water source. The high-temperature and high-pressure gaseous refrigerant becomes a medium-temperature and medium-pressure liquid refrigerant. After passing through the filter, it enters the air-side heat exchanger 150, where it exchanges heat with the air and becomes a low-pressure and high-temperature gaseous refrigerant. Finally, it returns to the compressor 110 through the four-way valve 130 and the gas-liquid separator 140, completing one heating refrigerant cycle.

[0124] Throughout the entire heating cycle, the refrigerant undergoes cooling and heat exchange through the first water-cooled heat exchanger 120 and the user-side water source, while evaporation and heat exchange are achieved through the air-side heat exchanger 150 and the air source. Compared to the water-cooled heat exchange method, the air-cooled heating method has higher heating efficiency, thus achieving high-efficiency heating.

[0125] In the structural design of the heat pump unit, an air-side heat exchanger 150 and a second water-cooled heat exchanger 160 are arranged in parallel. When the unit is in cooling operation, the first pipeline 180 can be closed by controlling it, so that the second water-cooled heat exchanger 160 and the first water-cooled heat exchanger 120 cooperate to circulate the refrigerant for cooling. The cooling and heat exchange methods are all carried out through water cooling, which is consistent with the heat exchange method of water-cooled heat pump units, thus achieving high-efficiency cooling.

[0126] During heating, the second water-cooled heat exchanger 160 can be controlled not to participate in the circulation. Instead, the air-side heat exchanger 150 and the first water-cooled heat exchanger 120 are used in combination, so that the refrigerant circulates between the air-side heat exchanger 150 and the first water-cooled heat exchanger 120. During evaporative heat exchange, heat exchange is carried out through the air-side heat exchanger 150, so that the heat exchange method is consistent with the heat exchange method of the air-cooled heat pump unit. This achieves high-efficiency heating of the unit. The entire heat pump unit structure can simultaneously take into account both cooling and heating, achieving high-efficiency cooling and heating effects.

[0127] In some embodiments of this application, the heat pump unit includes: a detection component for detecting the temperature of the air-side heat exchanger, the exhaust temperature, the high-pressure pressure, and the suction pressure, including:

[0128] Temperature sensor used to detect the temperature Te of the heat exchange tubes in the air-side heat exchanger;

[0129] A high-pressure sensor is installed on the compressor discharge side to detect the pressure on the high-pressure side and obtain the saturation temperature of the refrigerant. The high-pressure is Pd, and the refrigerant saturation temperature Td_p corresponding to the high-pressure Pd can be determined by existing technology.

[0130] The suction pressure sensor is located on the suction side of the compressor and is used to detect the suction pressure of the compressor, which is Ps.

[0131] The exhaust temperature sensor is used to detect the temperature on the exhaust side of the compressor, which is Td.

[0132] The controller is configured to:

[0133] The superheat of the air-side heat exchanger is obtained based on the temperature and high pressure of the air-side heat exchanger detected by the detection component.

[0134] If the superheat of the air-side heat exchanger is Tesh, then Tesh = Te - Td_p.

[0135] The first cooling mode requires three stages when it is first started: the start-up stage, the switching preparation stage, and the normal operation stage. Through these three stages, the refrigerant and lubricating oil stored in the air-side heat exchanger can be transferred to the first water-cooled heat exchanger and the second water-cooled heat exchanger.

[0136] Start-up phase: The main purpose of this phase is to convert the refrigerant stored in the air-side heat exchanger 150 into a high-pressure superheated gaseous state, which facilitates the migration of refrigerant and lubricating oil during the switching preparation phase.

[0137] During this stage of operation, based on the changes in high pressure Pd, the refrigerant saturation temperature Td_p corresponding to high pressure Pd, the temperature Te of the coil of air-side heat exchanger 150, the superheat Tesh of air-side heat exchanger 150 (Tesh = Te - Td_p), the exhaust temperature Td, and the suction pressure Ps, the coordinated actions of the entire unit's components convert the refrigerant in air-side heat exchanger 150 into high-temperature, high-pressure superheated gas. This prepares for secondary refrigerant distribution, prevents unused air-side heat exchanger 150 from storing excessive lubricating oil and refrigerant, which could cause the unit to lack refrigerant and lubricating oil during operation, and improves the unit's operational stability.

[0138] During the initial operation phase, the controller controls the control valves to open the first pipeline 180, disconnect the second pipeline 190, and start the compressor 110.

[0139] A first refrigerant flow path is formed between the compressor 110, the first water-side heat exchanger, the first throttling device 510, and the air-side heat exchanger 150.

[0140] The refrigerant flows from the compressor 110 into the air-side heat exchanger 150, the first throttling device 510, and the first water-side heat exchanger before returning to the compressor 110.

[0141] When the first refrigerant flow path is running, the controller controls the opening degree of the first throttling device 510 and the start / stop state of the fan with the target superheat range and target exhaust temperature range pre-stored in the controller as the target, so that the detected superheat and exhaust temperature of the air-side heat exchanger 150 approach the target superheat range and target exhaust temperature range, thus ensuring that the refrigerant in the air-side heat exchanger 150 is converted into a high-temperature and high-pressure superheated gas.

[0142] If the refrigerant stored in the air-side heat exchanger 150 is removed from the air-side heat exchanger 150, the amount of refrigerant and lubricating oil in the system can be ensured to meet the system operation requirements.

[0143] When the controller obtains the first preset conditions for the first throttling device 510's operating time, exhaust temperature, and intake pressure, it will end the control of the activation phase and enter the switching preparation phase.

[0144] The first preset condition is used to determine the end of the control during the initiation phase.

[0145] When entering the switching preparation stage, the controller will control the compressor 110 to stop running and the fan to stop running, and control the first throttling device 510 to maintain the first preset opening so that the high temperature and high pressure superheated gas and internal lubricating oil in the air-side heat exchanger 150 are removed from the air-side heat exchanger 150.

[0146] The first preset opening degree is the full opening degree of the first throttling device.

[0147] During the switching preparation phase, the pressure difference after the compressor 110 stops is mainly used to transfer the superheated refrigerant stored in the air-side heat exchanger to the gas-liquid separator or the first water-cooled heat exchanger 120 on the low-pressure side under the action of high and low pressure difference. At the same time, the lubricating oil stored in the finned heat exchanger can also be transferred out of the air-side heat exchanger along with the refrigerant under the action of pressure difference and enter the unit to participate in the circulation.

[0148] After the switchover preparation phase control is completed, the refrigerant and lubricating oil in the air-side heat exchanger 150 are determined by detecting the high pressure and suction pressure.

[0149] When the difference between the high pressure and the suction pressure meets the preset switching conditions, the unit can be controlled to enter the normal operation stage of the first cooling mode.

[0150] The preset switching condition is used to determine whether the refrigerant and lubricating oil in the air-side heat exchanger 150 have been completely removed.

[0151] Once the heat pump unit enters normal operation, the controller can control the control valve 170 to disconnect the first pipe 180 and open the second pipe 190.

[0152] After all the above actions are completed, the unit switches to the first cooling mode and maintains this operating state until a shutdown signal is received.

[0153] If the first cooling mode is not the first time the machine is turned on, there is no need to go through the two stages of startup and switching preparation; you can directly switch to the normal operation stage.

[0154] After the compressor 110 starts running, the refrigerant is discharged from the exhaust side of the compressor 110 and enters the air-side heat exchanger 150 through the four-way valve. Due to the opening control of the first throttling device 510 and the fan control, the heat exchange effect of the air-side heat exchanger 150 is changed, so that the refrigerant in the air-side heat exchanger 150 is converted into a high-temperature and high-pressure superheated gas, and then enters the first water-cooled heat exchanger 120 and flows back to the compressor 110.

[0155] After the compressor 110 stops running, the refrigerant in the air-side heat exchanger 150 is a superheated gas with high pressure. Under the action of the high and low pressure difference, it will drive the internal lubricating oil to move out, so that the refrigerant and lubricating oil will migrate out of the air-side heat exchanger 150.

[0156] The above embodiments have the following advantages and effects:

[0157] In this embodiment, before the heat pump unit is pre-activated in the first cooling mode, the first pipeline 180 is first opened to form a first refrigerant flow path between the first water-cooled heat exchanger 120 and the compressor 110 in the air-side heat exchanger 150. When the refrigerant flows in the first refrigerant flow path, the refrigerant in the air-side heat exchanger 150 is converted into a high-temperature and high-pressure superheated gas by controlling the first throttling device 510 and the fan. By controlling the compressor 110 to stop, the high-temperature and high-pressure superheated gas stored in the air-side heat exchanger 150 is removed from the air-side heat exchanger 150 by utilizing the pressure difference.

[0158] Since the first water-cooled heat exchanger 120 is used when the first cooling mode is running, it can be ensured that the refrigerant and lubricating oil of the entire unit will not be stored in the air-side heat exchanger 150 which does not participate in the circulation when the first cooling mode is running, thus ensuring that the refrigerant and lubricating oil in the unit are fully used for the first cooling mode.

[0159] By using the control method described above to remove refrigerant and lubricating oil from unused heat exchangers, the entire heat pump unit can be charged with refrigerant without overcharging. Only the appropriate amount of refrigerant and lubricating oil needs to be charged. During operation, the above control method can always migrate the refrigerant and lubricating oil to the running refrigerant flow path, avoiding the storage of refrigerant and lubricating oil in the unused heat exchangers. This avoids a series of problems caused by insufficient refrigerant and compressor 110 lubricating oil, such as high system exhaust temperature, low suction pressure, poor energy efficiency, and compressor 110 wear. It ensures that the entire unit always operates in the optimal control state, improving the unit's performance and operational stability.

[0160] In some embodiments of the present application, the controller is configured to: after the compressor 110 is turned on, the first throttling device 510 operates at an initial first opening for a preset time, and then adjusts the opening of the first throttling device 510 and the start / stop state of the fan according to the first adjustment rule so that the superheat degree of the air-side heat exchanger 150 and the exhaust gas temperature tend to the target superheat degree range and the target exhaust gas temperature range.

[0161] The preset time is a set time, which is T_s1 seconds.

[0162] The first opening is the initial opening at which the first throttling device 510 operates, which is Ev_s_by.

[0163] Within T_s1 seconds of the starting stage of the unit, the controller controls the opening of the first throttling device 510 to maintain at the Ev_s_by opening, and at the same time controls the fan to stop running while the compressor 110 is running. After the unit has run for T_s1 seconds, the opening of the first throttling device 510 and the fan are then controlled according to the target superheat degree range and the target exhaust gas temperature range pre-stored in the controller. By controlling the opening of the first throttling device 510, the state of the refrigerant inside the air-side heat exchanger 150 can be changed. By controlling the start / stop of the fan, the heat exchange effect of the air-side heat exchanger 150 is changed, and thus the state of the refrigerant inside the air-side heat exchanger 150 is changed.

[0164] The above embodiments have the following advantages and effects:

[0165] After the unit has run for the preset time, the controller can obtain the superheat degree and the exhaust gas temperature of the air-side heat exchanger 150. The first adjustment rule for controlling the opening of the first throttling device 510 and the start / stop of the fan according to the superheat degree and the exhaust gas temperature of the air-side heat exchanger 150 is pre-stored in the controller; during adjustment, the opening of the first throttling device 510 and the start / stop of the fan can be adjusted and controlled according to the obtained different superheat degree values and exhaust gas temperature values of the air-side heat exchanger 150 in accordance with the first adjustment rule, so that the actual superheat degree and the exhaust gas temperature of the air-side heat exchanger 150 infinitely approach the target superheat degree range and the target exhaust gas temperature range, so as to ensure that the refrigerant in the air-side heat exchanger 150 can be converted into a high-temperature and high-pressure superheated gas state, which is convenient for it to be removed from the air-side heat exchanger 150.

[0166] In some embodiments of the present application, wherein, the target superheat degree range is: Tesh≥a,

[0167] The target exhaust gas temperature range is b lower < Td < b middle, and the set upper limit temperature is b upper.

[0168] Refer to Figure 12 As shown, the first adjustment rule includes:

[0169] The first rule: When the superheat degree of the air-side heat exchanger 150 is within the target superheat degree range and the exhaust gas temperature reaches the upper limit of the set upper limit temperature, control the first throttling device 510 to increase the opening degree and control the fan to start.

[0170] That is, when Tesh≥a and Td≥b upper are satisfied, control the first throttling device 510 to increase the first preset opening degree on the basis of the original opening degree, where the first preset opening degree is: Ev_s_by / B.

[0171] When the superheat degree meets the requirements and the exhaust gas temperature reaches the upper limit of the set upper limit temperature, it means that the exhaust gas temperature is too high. The exhaust gas temperature value can be quickly reduced by increasing the opening degree of the first throttling device 510 and cooperating with the opening of the fan for heat dissipation.

[0172] The first adjustment rule includes: The second rule: When the superheat degree of the air-side heat exchanger 150 is within the target superheat degree range and the exhaust gas temperature reaches the upper limit of the target exhaust gas temperature range, control the first throttling device 510 to increase the opening degree and control the fan to stop.

[0173] That is, when Tesh≥a and Td≥b middle are satisfied, control the first throttling device 510 to increase the first preset opening degree on the basis of the original opening degree.

[0174] When the superheat degree meets the requirements and the exhaust gas temperature reaches the upper limit of the target exhaust gas temperature range, it means that the exhaust gas temperature is relatively high. The exhaust gas temperature value can be reduced only by increasing the opening degree of the first throttling device 510.

[0175] The first adjustment rule includes: The third rule: When it is obtained that the superheat degree on the air side is within the target superheat degree range and the exhaust gas temperature is within the target exhaust gas temperature range, control the first throttling device 510 to operate at the first opening degree and control the fan to stop.

[0176] That is, when Tesh≥a and Td≥b lower are satisfied, the first throttling device 510 can just maintain the initial opening degree.

[0177] When the superheat degree on the air side is within the target superheat degree range and the exhaust gas temperature is within the target exhaust gas temperature range, it means that both meet the requirements and no control is needed.

[0178] The first adjustment rule includes the fourth rule: When it is obtained that the superheat degree of the air-side heat exchanger 150 is within the target superheat degree range and the exhaust gas temperature reaches the lower limit of the target exhaust gas temperature range, control the first throttling device 510 to reduce the opening degree and control the fan to stop.

[0179] That is, when Tesh≥a and Td<b lower are satisfied, control the first throttling device 510 to reduce the first preset opening degree on the basis of the original opening degree.

[0180] When the superheat of the air-side heat exchanger 150 is within the target superheat range, and the exhaust temperature reaches the lower limit of the target exhaust temperature range, it indicates that the exhaust temperature is too low. At this time, the exhaust temperature can be increased by reducing the opening of the first throttling device 510 to bring it closer to the target exhaust temperature range.

[0181] Fifth rule: When the superheat of the air-side heat exchanger 150 reaches the lower limit of the target superheat range, control the first throttling device 510 to increase its opening and control the fan to stop.

[0182] If Tesh≤a, then the first throttling device 510 is controlled to increase a second preset opening degree on the basis of the original opening degree, wherein the second preset opening degree is Ev_s_by / D.

[0183] The priority of the first rule, the second rule, the third rule, the fourth rule, and the fifth rule decreases in that order.

[0184] The set upper limit temperature is greater than the upper limit of the target exhaust temperature range.

[0185] The above embodiments have the following advantages and effects:

[0186] By setting the first to fifth rules, when the controller obtains the superheat and exhaust temperature of the air-side heat exchanger 150, it can accurately control the opening of the first throttling device 510 and the start and stop of the fan according to the above five rules, ensuring that the refrigerant in the air-side heat exchanger 150 can be converted into a superheated gaseous state.

[0187] In some embodiments of this application, the controller is configured to: after each preset time period, sequentially determine the rules that the superheat and exhaust temperature of the air-side heat exchanger 150 meet according to the first to the fifth rules, and control the opening degree of the first throttling device 510 and the start / stop of the fan according to the rules they meet.

[0188] The preset time is tj seconds.

[0189] Every preset time interval, the controller acquires the actual superheat and exhaust temperature of the air-side heat exchanger 150, and then makes a judgment according to the order of the first to the fifth rules to determine which rule of the first to the fifth rules the superheat and exhaust temperature of the air-side heat exchanger 150 meet. The opening degree of the first throttling device 510 and the start and stop of the fan are controlled according to the rule that meets the rule.

[0190] When the superheat and exhaust temperature of the air-side heat exchanger 150 meet two or more rules, the rule with the highest priority is executed in descending order of priority.

[0191] Reference Figure 11As shown, the control method for the unit operating in the first cooling mode includes the following steps:

[0192] S110: During the initial stage T_s1 seconds, the first throttling device 510 is maintained at the Ev_s_by opening, the fan stops, the compressor runs, the first pipeline 180 is connected, and the second pipeline 190 is disconnected;

[0193] S120: After T_s1 seconds, the following judgments are made in sequence, and the superheat and exhaust temperature of the air-side heat exchanger 150 are judged repeatedly according to the first to fifth rules every tj seconds, and the opening of the first throttling device 510 and the start / stop status of the fan are adjusted.

[0194] S130: Does the first throttling device 510's operating time, exhaust temperature, and intake pressure meet the first preset conditions?

[0195] If the first preset condition is not met, proceed to S120;

[0196] S140: If the first preset condition is met, proceed to the switching preparation stage;

[0197] S150: Does the difference between the high pressure and the inhalation pressure meet the preset switching conditions?

[0198] S160: If the preset switching conditions are met, the system will switch to the first cooling mode.

[0199] In some embodiments of this application, the first preset condition includes at least the following:

[0200] The first throttling device 510 operates for a time up to the upper limit of a set time threshold, where the set time threshold is T_s1 + T_s2. The operating time of the first throttling device 510 is the corresponding continuous operating time of the starting phase.

[0201] Alternatively, the exhaust temperature reaches the upper limit of the exhaust temperature threshold, that is, the exhaust temperature exceeds or equals the exhaust temperature threshold, which is Td_max℃.

[0202] Alternatively, the inspiratory pressure reaches the lower limit of the inspiratory pressure threshold, i.e., the inspiratory pressure is less than or equal to the inspiratory pressure threshold, which is Ps_min MPa.

[0203] When the controller detects that any one of the following conditions is met: the running time of the start-up phase, the exhaust temperature value, or the intake pressure value, it can exit the start-up phase control and enter the switching preparation phase.

[0204] In some embodiments of this application, the first preset condition further includes the cumulative time for executing the first rule or the fifth rule reaching a set upper limit value for the cumulative time.

[0205] Set the cumulative time to T_start seconds, and set the cumulative time to be greater than the preset time.

[0206] If the cumulative time of executing the first rule or the cumulative time of executing the fifth rule is greater than or equal to T_start seconds, the control of the initiation phase can be exited.

[0207] Since the controller performs a judgment and control once every preset time, after executing a certain rule, it will perform control again after a preset time. If a certain rule is executed multiple times, its cumulative execution time can be recorded.

[0208] For example, if the set cumulative time is 10 seconds and the preset time is 2 seconds, the controller controls the opening of the first throttling device 510 according to the first rule for the first time and continues for 2 seconds. After 2 seconds, it makes a judgment again. If it still meets the first rule, it continues to control the opening of the first throttling device 510 and the fan status according to the first rule for another 2 seconds. At this time, the cumulative execution time of the first rule is 4 seconds. The cycle continues in this way. If the cumulative time of the first rule reaches 10 seconds, the control of the starting stage will be terminated.

[0209] In some embodiments of this application, the preset switching conditions include:

[0210] First switching condition: The difference between the high pressure and the inhalation pressure reaches the lower limit of the first switching threshold, which is f.

[0211] The first switching condition is: Pd - Ps ≤ f

[0212] Alternatively, the second switching condition is: the difference between the high pressure and the inhalation pressure reaches the lower limit of the second switching threshold and the duration reaches the upper limit of the preset switching time, where the second switching threshold is g and the preset switching time is T_p.

[0213] The second switching condition is: Pd - Ps ≤ g and lasts for T_p seconds.

[0214] The first switching threshold is less than the second switching threshold.

[0215] The first switching threshold is relatively small, and the second switching threshold is slightly larger. For example, the first switching threshold can be 0.01, and the second switching threshold can be 0.1.

[0216] When the difference between the high pressure and the suction pressure of the compressor 110 is small, it can be determined that the refrigerant in the air-side heat exchanger 150 has been basically completely removed.

[0217] When the difference between the high pressure and the suction pressure is detected to be slightly large, but this difference has persisted for the preset switching time, it also indicates that the pressure has stabilized and the refrigerant in the air-side heat exchanger 150 has been basically removed.

[0218] Therefore, when the controller detects, if it finds that either the first switching condition or the second switching condition is met, it can control the first pipe 180 to disconnect and the second pipe 190 to open, so that the unit enters the first cooling mode.

[0219] In some embodiments of this application, the heat pump unit has a second cooling mode. When the heat pump unit is in the second cooling mode, the controller controls the first pipeline 180 to be turned on and the second pipeline 190 to be turned off, forming a second cooling cycle loop between the compressor 110, the four-way valve, the air-side heat exchanger 150, the first water-cooled heat exchanger 120 and the gas-liquid separator.

[0220] When the second water-cooled heat exchanger 160 fails, the air-side heat exchanger 150 can be used to replace the second water-cooled heat exchanger 160 to participate in the refrigeration cycle, ensuring the reliable operation of the unit.

[0221] Reference Figure 10 As shown, when running in the second cooling mode, the refrigerant enters the four-way valve 130 after exiting the compressor 110, and then enters the air-side heat exchanger 150 to exchange heat with the air. The high-temperature and high-pressure gaseous refrigerant becomes a medium-temperature and medium-pressure liquid refrigerant. The refrigerant after heat exchange enters the first water-cooled heat exchanger 120 and exchanges heat with the first hot water pipe through the first water-cooled heat exchanger 120. The refrigerant after heat exchange becomes a low-temperature and low-pressure gaseous refrigerant, and finally enters the compressor 110 through the four-way valve 130 and the gas-liquid separator 140.

[0222] The second cooling mode also requires three stages when it is first started: the startup stage, the switching preparation stage, and the normal operation stage, which are the same as those of the first cooling mode.

[0223] During the startup phase: the controller is configured as follows:

[0224] The first control line 180 is disconnected, the second control line 190 is connected, and the compressor 110 is running.

[0225] A second refrigerant flow path is formed between the compressor 110, the first water-cooled heat exchanger 120, and the second water-cooled heat exchanger 160.

[0226] The opening degree of the first throttling device 510 and the start and stop of the water pump on the side of the second water-cooled heat exchanger 160 are controlled with the target superheat and target exhaust temperature pre-stored in the controller, so that the refrigerant in the second water-cooled heat exchanger 160 is converted into a high-temperature and high-pressure superheated gas.

[0227] By controlling the opening degree of the first throttling device 510 and the start / stop state of the water pump on the side of the second water-cooled heat exchanger 160, the detected superheat and exhaust temperature of the air-side heat exchanger 150 can be made to approach the target superheat range and target exhaust temperature range, thus ensuring that the refrigerant in the air-side heat exchanger 150 is converted into a high-temperature and high-pressure superheated gas.

[0228] When the operating time, exhaust temperature and intake pressure of the first throttling device 510 meet the second preset conditions, the compressor 110 is controlled to stop running and the water pump on the side of the second water-cooled heat exchanger 160 is controlled to maintain the second preset opening so that the high-temperature and high-pressure superheated gas and internal lubricating oil in the second water-cooled heat exchanger 160 are removed from the second water-cooled heat exchanger 160.

[0229] The second preset condition is used to determine the end of the control during the initiation phase.

[0230] When the second preset condition is met, the switching preparation stage can be entered, the compressor 110 is stopped, the water pump on the second water-cooled heat exchange side is stopped, and the high-temperature and high-pressure superheated gas and lubricating oil in the second water-cooled heat exchanger 160 are removed by pressure difference.

[0231] When the difference between the high pressure and the intake pressure meets the preset switching conditions, the control valve opens the first pipeline 180 and disconnects the second pipeline 190.

[0232] The preset switching conditions are used to determine whether the refrigerant and lubricating oil have been completely removed from the second water-cooled heat exchanger 160. The preset switching conditions for the second water-cooled heat exchanger 160 to enter the normal operation stage from the switching preparation stage are the same as those for the air-side heat exchanger 150, and will not be described again here.

[0233] When the difference between the high pressure and the suction pressure meets the preset switching conditions, the unit can be controlled to enter the normal operation stage of the second cooling mode.

[0234] The above embodiments have the following advantages and effects:

[0235] In this embodiment, before the second cooling mode is pre-activated, the second pipeline 190 is first opened to form a second refrigerant flow path between the second water-cooled heat exchanger 160, the first water-cooled heat exchanger 120, and the compressor 110. When the refrigerant flows in the second refrigerant flow path, the refrigerant in the second water-cooled heat exchanger 160 is converted into a high-temperature, high-pressure superheated gas by controlling the first throttling device 510 and the water pump on the second water-cooled heat exchanger 160 side. By controlling the compressor 110 to stop, the high-temperature, high-pressure superheated gas stored in the second water-cooled heat exchanger 160 is removed from the second water-cooled heat exchanger 160 by utilizing the pressure difference. Since the air-side heat exchanger 150 is used when the second cooling mode is running, it can be ensured that the refrigerant and lubricating oil of the entire unit will not be stored in the second water-cooled heat exchanger 160, which does not participate in the circulation, and that the refrigerant and lubricating oil in the unit are fully used for the second cooling mode.

[0236] By using the control method described above to remove refrigerant and lubricating oil from unused heat exchangers, the entire heat pump unit can be charged with refrigerant without overcharging. Only the appropriate amount of refrigerant and lubricating oil needs to be charged. During operation, the above control method can always migrate the refrigerant and lubricating oil to the running refrigerant flow path, avoiding the storage of refrigerant and lubricating oil in the unused heat exchangers. This avoids a series of problems caused by insufficient refrigerant and compressor 110 lubricating oil, such as high system exhaust temperature, low suction pressure, poor energy efficiency, and compressor 110 wear. It ensures that the entire unit always operates in the optimal control state, improving the unit's performance and operational stability.

[0237] In some embodiments of this application, the controller is configured to: after the compressor 110 is turned on and the first throttling device 510 operates at an initial second opening for a preset water-cooling time, adjust the opening of the first throttling device 510 and the start / stop state of the water pump on the second water-cooled heat exchanger 160 side according to a second adjustment rule so that the superheat and exhaust temperature of the second water-cooled heat exchanger 160 are close to the target superheat range and the target exhaust temperature range.

[0238] The water cooling preset time is a set time, which is T_f1 seconds.

[0239] The initial opening degree of the first throttling device 510 is Ev_s_fl. Since the structures of the second water-cooled heat exchanger 160 and the air-side heat exchanger 150 are different, the initial opening degree setting and opening degree adjustment value of the second throttling device are different from those of the air-side heat exchanger 150.

[0240] Their control methods are the same. Within T_f1 seconds at the starting stage of the unit, the controller controls the opening degree of the first throttle device 510 to remain at the Ev_s_fl opening degree, and at the same time controls the pump on the side of the second water-cooled heat exchanger 160 to stop, and the compressor 110 runs.

[0241] After the preset water-cooling time, the opening degree of the first throttle device 510 and the start / stop state of the pump on the side of the second water-cooled heat exchanger 160 are controlled according to the second adjustment rule.

[0242] In some embodiments of the present application, the target superheat degree of the second water-cooled heat exchanger 160 is TLsh, and its corresponding range is: TLsh≥a;

[0243] The target exhaust gas temperature range is b lower < Td < b middle, and the set upper limit temperature is b upper.

[0244] Refer to Figure 14 As shown, the second adjustment rule includes:

[0245] The sixth rule: When the superheat degree of the second water-cooled heat exchanger 160 is within the target superheat degree range and the exhaust gas temperature reaches the upper limit of the set upper limit temperature, control the first throttle device 510 to increase the opening degree and control the pump on the side of the second water-cooled heat exchanger 160 to start.

[0246] That is, when TLsh≥a and Td≥b upper are satisfied, control the first throttle device 510 to increase the third preset opening degree on the basis of the original opening degree, where the third preset opening degree is: Ev_s_f| / E.

[0247] When the superheat degree meets the requirements and the exhaust gas temperature reaches the upper limit of the set upper limit temperature, it means that the exhaust gas temperature is too high, and the exhaust gas temperature value can be quickly reduced by increasing the opening degree of the first throttle device 510 and starting the pump on the side of the second water-cooled heat exchanger 160 for heat dissipation in cooperation.

[0248] The seventh rule: When the superheat degree of the second water-cooled heat exchanger 160 is within the target superheat degree range and the exhaust gas temperature reaches the upper limit of the target exhaust gas temperature range, control the first throttle device 510 to increase the opening degree and control the pump on the side of the second water-cooled heat exchanger 160 to stop.

[0249] That is, when TLsh≥a and Td≥b middle are satisfied, control the first throttle device 510 to increase the third preset opening degree on the basis of the original opening degree.

[0250] When the superheat degree meets the requirements and the exhaust gas temperature reaches the upper limit of the target exhaust gas temperature range, it means that the exhaust gas temperature is relatively high, and the exhaust gas temperature value can be reduced only by increasing the opening degree of the first throttle device 510.

[0251] Eighth rule: When the superheat degree of the second water-cooled heat exchanger 160 is within the target superheat degree range and the exhaust gas temperature is within the target exhaust gas temperature range, control the first throttling device 510 to operate at the second opening degree, and control the water pump on the side of the second water-cooled heat exchanger 160 to stop.

[0252] That is, when TLsh≥a and Td≥b are satisfied, the first throttling device 510 can be maintained at the second opening degree.

[0253] Ninth rule: When the superheat degree of the second water-cooled heat exchanger 160 is within the target superheat degree range and the exhaust gas temperature reaches the lower limit of the target exhaust gas temperature range, control the first throttling device 510 to reduce the opening degree, and control the water pump on the side of the second water-cooled heat exchanger 160 to stop.

[0254] That is, when TLsh≥a and Td<b are satisfied, control the first throttling device 510 to reduce the third preset opening degree based on the original opening degree.

[0255] When the superheat degree of the air-side heat exchanger 150 is within the target superheat degree range and the exhaust gas temperature reaches the lower limit of the target exhaust gas temperature range, it indicates that the exhaust gas temperature is too low. At this time, the opening degree of the first throttling device 510 can be reduced to increase the exhaust gas temperature and make it close to the target exhaust gas temperature range.

[0256] Tenth rule: When the superheat degree of the second water-cooled heat exchanger 160 reaches the lower limit of the target superheat degree range, control the first throttling device 510 to increase the opening degree, and control the water pump on the side of the second water-cooled heat exchanger 160 to stop.

[0257] That is, when TLsh≤a is satisfied, control the first throttling device 510 to increase the fourth preset opening degree based on the original opening degree, where the fourth preset opening degree is Ev_s_by / D.

[0258] Among them, the priorities of the sixth rule, the seventh rule, the eighth rule, the ninth rule and the tenth rule decrease in turn;

[0259] The set upper limit temperature is greater than the upper limit value of the target exhaust gas temperature range.

[0260] In some embodiments of the present application, the controller is configured to: after a preset time interval, sequentially determine the rules that the superheat degree and the exhaust gas temperature of the second water-cooled heat exchanger 160 conform to according to the sixth rule to the tenth rule, and control the opening degree of the first throttling device 510 and the start and stop of the water pump on the side of the second water-cooled heat exchanger 160 according to the rules it conforms to.

[0261] Every preset time interval, the controller acquires the actual superheat and exhaust temperature of the second water-cooled heat exchanger 160, and then makes a judgment according to the order of the sixth to the tenth rules to determine which rule of the sixth to the tenth rules the superheat and exhaust temperature of the second water-cooled heat exchanger 160 meet. The controller then controls the opening of the first throttling device 510 and the start and stop of the water pump on the second water-cooled heat exchanger 160 side according to the rule that it meets.

[0262] When the superheat and exhaust temperature of the air-side heat exchanger 150 meet two or more rules, the rule with the highest priority is executed in descending order of priority.

[0263] Reference Figure 13 As shown, the control method for the unit to operate in the second cooling mode includes the following steps:

[0264] S210: During the initial stage T_f1 seconds, the first throttling device 510 is maintained at the Ev_s_fl opening, the water pump on the second water-cooled heat exchanger 160 side stops, the compressor 110 runs, the first pipeline 180 is disconnected, and the second pipeline 190 is connected.

[0265] S220: After T_f1 seconds, every tj seconds, repeat the judgment of the superheat of the second water-cooled heat exchanger 160 and the exhaust temperature according to the sixth to tenth rules, and adjust the opening of the first throttling device 510 and the start / stop status of the water pump.

[0266] S230: Does the first throttling device 510's operating time, exhaust temperature, and intake pressure meet the second preset condition?

[0267] If the second preset condition is not met, proceed to S220;

[0268] S240: If the second preset condition is met, proceed to the handover preparation stage;

[0269] S250: Does the difference between the high pressure and the inhalation pressure meet the preset switching conditions?

[0270] S260: When the preset switching conditions are met, the system will switch to the second cooling mode.

[0271] In some embodiments of this application, the second preset condition includes at least the following:

[0272] The first throttling device 510 operates for a second set time, i.e., T_f1+T_f2 seconds;

[0273] Alternatively, the exhaust temperature reaches the upper limit of the exhaust temperature threshold.

[0274] Alternatively, the inhalation pressure reaches the lower limit of the inhalation pressure threshold.

[0275] Alternatively, the cumulative time for executing the sixth or tenth rule reaches the upper limit of the set cumulative time.

[0276] In some embodiments of this application, reference is made to Figure 4 As shown, the heat pump unit includes: a subcooler 200, which is configured as follows:

[0277] When the heat pump unit is in the first cooling mode, the subcooler 200 is connected between the second water-cooled heat exchanger 160 and the first water-cooled heat exchanger 120 to cool the refrigerant flowing out of the second water-cooled heat exchanger 160.

[0278] Reference Figure 5 , 6 As shown, when the first cooling mode is running, the refrigerant enters the second water-cooled heat exchanger 160 and exchanges heat with the water flow. After changing from a high-temperature, high-pressure gaseous refrigerant to a medium-temperature, medium-pressure liquid refrigerant, it passes through a filter and enters the subcooler 200 for heat exchange. After heat exchange in the subcooler 200, the refrigerant is cooled again. After being throttled and depressurized by the first throttling device 510 connected to the subcooler 200, the refrigerant changes from a medium-temperature, medium-pressure liquid to a low-temperature, low-pressure liquid refrigerant. The low-temperature, low-pressure liquid refrigerant then enters the first water-cooled heat exchanger 120 and then flows back to the compressor 110.

[0279] The refrigerant flowing out of the second water-cooled heat exchanger 160 is further cooled by the subcooler 200, which improves the cooling effect.

[0280] In some embodiments of this application, the subcooler 200 is configured such that, when the heat pump unit is in heating mode, the subcooler 200 is connected between the first water-cooled heat exchanger 120 and the air-side heat exchanger 150, for cooling the refrigerant flowing out of the first water-cooled heat exchanger 120. (Refer to...) Figure 8 As shown, during heating mode operation, the refrigerant entering the first water-cooled heat exchanger 120 exchanges heat with the first hot water pipe flowing through it, changing from a high-temperature, high-pressure gaseous refrigerant to a medium-temperature, medium-pressure liquid refrigerant. After passing through a filter, it enters the subcooler 200 for heat exchange. The refrigerant after heat exchange in the subcooler 200 is cooled again. After being throttled and depressurized by the first throttling device 510 connected to the subcooler 200, the refrigerant changes from a medium-temperature, medium-pressure liquid to a low-temperature, low-pressure liquid refrigerant. The low-temperature, low-pressure liquid refrigerant enters the air-side heat exchanger 150, exchanges heat with the air source, and becomes a low-pressure, high-temperature gaseous refrigerant. Finally, it returns to the compressor 110 through the four-way valve 130 and the gas-liquid separator 140.

[0281] After the refrigerant flows out from the first water-cooled heat exchanger 120, it is cooled by the subcooler 200, and the temperature of the refrigerant is further reduced, thus achieving heating in a low-temperature environment.

[0282] In some embodiments of this application, when the heat pump unit is in the second cooling mode, the subcooler 200 is connected between the first water-cooled heat exchanger 120 and the air-side heat exchanger 150 for cooling the refrigerant.

[0283] In some embodiments of this application, the subcooler 200 is configured with a subcooler refrigerant flow path 210 through which the refrigerant flows, the subcooler refrigerant flow path 210 having an inlet 211 and an outlet 212.

[0284] Inlet 211 is the inlet used to introduce refrigerant.

[0285] The outlet section 212 is for the outlet, used to draw the refrigerant out from the refrigerant flow path 210 of the subcooler.

[0286] The main connecting pipe 300 is connected to the second water-cooled heat exchanger 160 and the air-side heat exchanger 150.

[0287] The inlet section 211 is closer to the main connecting pipe 300 than the outlet section 212.

[0288] The first connecting pipe 410 is connected to the inlet 211 of the main connecting pipe 300 and the refrigerant flow path 210 of the subcooler, and a first control valve 411 is provided on the first connecting pipe 410.

[0289] The second connecting pipe 420 is connected between the outlet 212 of the first water-cooled heat exchanger 120 and the refrigerant flow path 210 of the subcooler, and a second control valve 421 is provided on the second connecting pipe 420.

[0290] Reference Figure 5 As shown, during the first cooling mode operation, the refrigerant exits from the compressor 110 and enters the four-way valve 130, then enters the second water-cooled heat exchanger 160 to exchange heat with the cooling water. The high-temperature, high-pressure gaseous refrigerant becomes a medium-temperature, medium-pressure liquid refrigerant. After flowing out of the second water-cooled heat exchanger 160, the refrigerant enters the main connecting pipe 300, flows from the main connecting pipe 300 into the first connecting pipe 410, enters the inlet 211 of the subcooler refrigerant flow path 210 from the first connecting pipe 410, flows through the subcooler 200, exits from the outlet 212, enters the second connecting pipe 420, enters the first water-cooled heat exchanger 120 from the second connecting pipe 420, and flows back to the compressor 110 after passing through the four-way valve 130 and the gas-liquid separator 140 from the first water-cooled heat exchanger 120.

[0291] The first control valve 411 is a first check valve 620, used to limit the flow of refrigerant from the main connection pipe 300 along the first connection pipe 410;

[0292] The second control valve 421 is a second check valve 630, used to limit the flow of refrigerant from outlet 212 into the first water-side heat exchanger.

[0293] By cooperating with the first connecting pipe 410, the first control valve 411 on the first connecting pipe 410, the second connecting pipe 420 and the second control valve 421 on the first connecting pipe 410, and the control valve 170 for switching the first pipe 180 and the second pipe 190, the refrigerant can be restricted to circulate between the compressor 110, the four-way valve 130, the first water-cooled heat exchanger 120 and the second water-cooled heat exchanger 160 when the unit is in the first cooling operation mode, so as to achieve a high-efficiency cooling effect.

[0294] Some embodiments of this application include:

[0295] The third connecting pipe 430 is connected between the outlet of the first water-cooled heat exchanger 120 and the inlet 211 of the subcooler refrigerant flow path 210. A third control valve 431 and a high-pressure liquid storage tank 432 are provided on the third connecting pipe 430.

[0296] The fourth connecting pipe 440 is connected to the outlet 212 of the refrigerant flow path 210 of the subcooler and the first connecting pipe 410. A fourth control valve 441 is provided on the fourth connecting pipe 440.

[0297] The fifth control valve 450 is located between the connection point of the first pipeline and the main connecting pipeline and the connection point of the second pipeline and the main connecting pipeline, and is used to limit the flow direction of the refrigerant so that it flows into the air-side heat exchanger 150.

[0298] Reference Figure 8 As shown, during heating mode operation, the refrigerant exits from the compressor 110 and enters the four-way valve 130, then enters the first water-cooled heat exchanger 120 to exchange heat with the cooling water. The high-temperature, high-pressure gaseous refrigerant becomes a medium-temperature, medium-pressure liquid refrigerant. After flowing out of the first water-cooled heat exchanger 120, the refrigerant enters the third connecting pipe 430 and flows through the high-pressure liquid storage tank 432. The refrigerant flowing out of the third connecting pipe 430 enters the refrigerant pipe inlet 211 of the subcooler 200. After flowing through the subcooler 200, it flows out from the outlet 212 and enters the fourth connecting pipe 440. From the fourth connecting pipe 440, it enters the main connecting pipe 300 and flows into the air-side heat exchanger 150, four-way valve 130, and gas-liquid separator 140 before returning to the compressor 110.

[0299] Among them, the high-pressure liquid storage tank 432 is used to store high-pressure liquid to balance the amount of refrigerant used for cooling and heating.

[0300] The third control valve 431 is a third check valve used to limit the flow direction of refrigerant in the third connecting pipe 430.

[0301] The fourth control valve 441 is a fourth check valve used to limit the flow direction of the refrigerant flowing out of the outlet 212 in the fourth connecting pipe 440.

[0302] In some embodiments of this application, the refrigerant flow direction defined by the first control valve 411 is opposite to that defined by the third control valve 431.

[0303] Both the first connecting pipe 410 and the third connecting pipe 430 are connected to the inlet 211 of the refrigerant flow path 210 of the subcooler. Due to the flow direction limitation effect of the third control valve 431, the refrigerant flowing into the inlet 211 from the first connecting pipe 410 will not flow into the third connecting pipe 430.

[0304] Similarly, the refrigerant flowing from the third connecting pipe 430 to the inlet 211 will not flow into the first connecting pipe 410 due to the flow direction restriction effect of the first control valve 411.

[0305] The fifth control valve 450 is a fifth check valve, which is used to prevent the refrigerant flowing into the main connection pipe 300 from flowing into the second water-cooled heat exchanger, ensuring that the refrigerant can enter the air-side heat exchanger 150.

[0306] By cooperating with the third connecting pipe 430 and the third control valve 431, fourth connecting pipe 440, fourth control valve 441 and fifth control valve 450 on the third connecting pipe 430, and the control valve 170 for switching the first pipe 180 and the second pipe 190, the refrigerant can be restricted to circulate between the compressor 110, the four-way valve 130, the first water-cooled heat exchanger 120 and the air-side heat exchanger 150 when the unit is in heating mode, so as to achieve a high-efficiency heating effect.

[0307] Reference Figure 7 , Figure 9 As shown, in some embodiments of this application, a first throttling device 510 is provided on the refrigerant flow path 210 of the subcooler near the outlet 212. The first throttling device 510 is a first electronic expansion valve.

[0308] The diversion flow path 220 has one end connected to the refrigerant flow path 210 of the subcooler located between the first throttling device 510 and the subcooler 200, and the other end connected to the subcooler 200. A second throttling device 520 is provided on the diversion flow path 220, which is a second electronic expansion valve.

[0309] The compressor gas supply circuit 230 is connected at one end to the suction side of the compressor 110 and at the other end to the subcooler 200.

[0310] The refrigerant flowing out of the first water-cooled heat exchanger 120 or the second water-cooled air exchanger will flow through the refrigerant flow path 210 of the subcooler. Part of the refrigerant in the subcooler refrigerant flow path 210 enters the refrigerant circuit to participate in the circulation, and the other part is diverted to the diversion flow path 220. After being throttled and depressurized by the second throttling device 520, it flows back into the subcooler 200 to exchange heat with the refrigerant in the subcooler refrigerant flow path 210, so as to further reduce the temperature of the refrigerant in the subcooler refrigerant flow path 210. The refrigerant after flowing through the subcooler 200 enters the suction side of the compressor 110 through the compressor gas supply circuit 230.

[0311] The refrigerant flowing through the refrigerant flow path 210 of the subcooler exchanges heat with the refrigerant that flows out of the subcooler refrigerant flow path 210 and returns to the subcooler 200 after being throttled by the second throttling device 520. This further cools the refrigerant in the subcooler refrigerant flow path 210 and further reduces the temperature of the refrigerant.

[0312] In addition, the refrigerant after heat exchange in the subcooler enters the exhaust chamber of the compressor 110, reducing the exhaust temperature of the compressor and thus improving the unit's heating capacity.

[0313] Reference Figure 6 As shown, in some embodiments of this application, the air-side heat exchanger 150 is connected to the main connecting pipe 300 via the first pipe 180;

[0314] The control valve assembly includes:

[0315] The solenoid valve 610 is an electrically controlled valve and is located on the side of the first pipeline 180 near the main connecting pipeline 300.

[0316] The first one-way valve 620 is arranged on the first pipeline 180 between the air-side heat exchanger 150 and the electrically controlled valve 610;

[0317] The second check valve 630 is connected in parallel to the first pipeline 180, which is equipped with the first check valve 620 and the solenoid valve 610, via a branch pipeline 181. The valve direction of the second check valve 630 is opposite to that of the first check valve 620.

[0318] By coordinating the electronically controlled valve 610 and the first check valve 620, refrigerant from the air-side heat exchanger 150 can be prevented from leaking outwards and flowing into the main connecting pipe 300.

[0319] Meanwhile, the second one-way valve 630 can also prevent the refrigerant of the second water-cooled heat exchanger 160 from entering the air-side heat exchanger 150, thus preventing the refrigerant from being unable to participate in the circulation inside the air-side heat exchanger 150.

[0320] The use of a combination of a first check valve 620, a second check valve 630, and an electrically controlled valve 610 to prevent refrigerant from entering the air-side heat exchanger 150 or refrigerant leakage, along with the adoption of existing simple valve body components, can reduce the overall manufacturing cost of the heat pump unit.

[0321] Reference Figures 1-3 As shown, in some embodiments of this application, the control valve 170 includes:

[0322] The first valve 171 is used to control the opening and closing of the first pipeline 180;

[0323] The second valve 172 is used to control the on / off state of the second pipeline 190;

[0324] During refrigeration operation, the first valve 171 is closed, and the second valve 172 is open.

[0325] When heating is in operation, the first valve 171 is open and the second valve 172 is closed.

[0326] The first valve 171 is a two-way electric ball valve, and the second valve 172 is a two-way electric ball valve.

[0327] The simple valve structure of the two-way electric ball valve can reduce the overall production and manufacturing cost of the heat pump unit.

[0328] In some embodiments of this application, reference is made to Figure 6 As shown, the control valve 170 includes:

[0329] The first valve port is connected to the four-way valve 130 via a refrigerant pipeline;

[0330] The second valve port is connected to the first pipeline 180;

[0331] The third valve port is connected to the second pipeline 190;

[0332] During refrigeration operation, the first valve port and the second pipeline 190 are connected;

[0333] When heating is in operation, the first valve port and the first pipeline 180 are connected.

[0334] The control valve 170 is a three-way valve, which can be connected to the four-way valve 130, the first pipeline 180 and the second pipeline 190 respectively. The control of the first pipeline 180 and the second pipeline 190 is realized by switching the opening or closing between different valve ports of the three-way valve.

[0335] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A heat pump unit, characterized in that, Including: The refrigerant circuit is formed by connecting a compressor, a first water-cooled heat exchanger, a second heat exchanger group, a first throttling device, a four-way valve, and a gas-liquid separator. The second heat exchanger assembly includes: An air-side heat exchanger is connected to the first pipeline between the four-way valve and the first water-cooled heat exchanger; A fan is installed on the air-side heat exchanger side to drive the airflow in the air-side heat exchanger. The second water-cooled heat exchanger is connected in parallel with the air-side heat exchanger through the second pipeline; Control valves are installed on the first and second pipelines; The detection component is used to detect the temperature, exhaust temperature, high pressure, and suction pressure of the air-side heat exchanger. The controller is configured as follows: When the heat pump unit is in the first cooling mode, the control valve is used to disconnect the first pipeline and open the second pipeline. The superheat of the air-side heat exchanger is obtained based on the air-side heat exchanger temperature and high pressure detected by the detection component. Before the heat pump unit enters the first cooling mode, the compressor is controlled to run and the control valve is controlled to open the first pipeline to form a first refrigerant flow path between the compressor, the first water-cooled heat exchanger, the first throttling device, and the air-side heat exchanger. The opening degree of the first throttling device and the start and stop of the fan are controlled with the target superheat range and target exhaust temperature range pre-stored in the controller, so that the refrigerant in the air-side heat exchanger is converted into a high-temperature and high-pressure superheated gas. When the first throttling device's operating time, exhaust temperature, and intake pressure reach the first preset conditions, the compressor and fan are controlled to stop running, and the first throttling device is controlled to maintain the first preset opening so that the high-temperature and high-pressure superheated gas and internal lubricating oil in the air-side heat exchanger are removed from the air-side heat exchanger. When the difference between the high pressure and the intake pressure meets the preset switching conditions, the control valve disconnects the first pipeline and connects the second pipeline.

2. The heat pump unit according to claim 1, characterized in that, The controller is configured to adjust the opening of the first throttling device and the start / stop state of the fan according to the first adjustment rule after the first throttling device has been running at the initial first opening for a preset time, so that the superheat of the air-side heat exchanger and the exhaust temperature are close to the target superheat range and the target exhaust temperature range.

3. The heat pump unit according to claim 2, characterized in that, The first adjustment rule includes: First rule: When the superheat of the air-side heat exchanger is within the target superheat range and the exhaust temperature reaches the upper limit of the set upper limit temperature, control the first throttling device to increase the opening and control the fan to start. Second rule: When the superheat of the air-side heat exchanger is within the target superheat range and the exhaust temperature reaches the upper limit of the target exhaust temperature range, control the first throttling device to increase its opening and control the fan to stop. Third rule: When the superheat of the air-side heat exchanger is within the target superheat range and the exhaust temperature is within the target exhaust temperature range, control the first throttling device to maintain the first opening and control the fan to stop. Fourth rule: When the superheat of the air-side heat exchanger is within the target superheat range and the exhaust temperature reaches the lower limit of the target exhaust temperature range, control the first throttling device to reduce its opening and control the fan to stop. Fifth rule: When the superheat of the air-side heat exchanger reaches the lower limit of the target superheat range, control the first throttling device to increase its opening and control the fan to stop. The priority of the first rule, the second rule, the third rule, the fourth rule, and the fifth rule decreases in that order. The set upper limit temperature is greater than the upper limit of the target exhaust temperature range.

4. The heat pump unit according to claim 3, characterized in that, The controller is configured to: after each preset time period, sequentially determine the rules that the superheat of the air-side heat exchanger and the exhaust temperature meet according to the first to the fifth rules, and control the opening degree of the first throttling device and the start and stop of the fan according to the rules they meet.

5. The heat pump unit according to claim 4, characterized in that, The first preset condition includes at least the following: The first throttling device has reached the upper limit of the set time threshold during its operation. Alternatively, the exhaust temperature reaches the upper limit of the exhaust temperature threshold. Alternatively, the inhalation pressure reaches the lower limit of the inhalation pressure threshold.

6. The heat pump unit according to claim 1, characterized in that, The preset switching condition is: First switching condition: The difference between the high pressure and the inhalation pressure reaches the lower limit of the first switching threshold; Alternatively, the second switching condition is: the difference between the high-pressure and the inhalation pressure reaches the lower limit of the second switching threshold and the duration is greater than the preset switching time; The first switching threshold is less than the second switching threshold.

7. The heat pump unit according to claim 1, characterized in that, The heat pump unit has a second cooling mode. When the heat pump unit is in the second cooling mode, the control valve controls the first pipeline to be open and the second pipeline to be closed, forming a second cooling cycle loop between the compressor, four-way valve, air-side heat exchanger, first water-cooled heat exchanger and gas-liquid separator. The controller is configured to: Before the heat pump unit enters the second cooling mode, the compressor is controlled to run and the control valve is controlled to open the second pipeline to form a second refrigerant flow path between the compressor, the first water-cooled heat exchanger, and the second water-cooled heat exchanger. The opening degree of the first throttling device and the start and stop of the water pump on the side of the second water-cooled heat exchanger are controlled with the target superheat and target exhaust temperature pre-stored in the controller, so that the refrigerant in the second water-cooled heat exchanger is converted into a high-temperature and high-pressure superheated gas. When the first throttling device's operating time, exhaust temperature, and intake pressure meet the second preset conditions, the compressor is controlled to stop running, the water pump on the second water-cooled heat exchanger side is controlled to stop running, and the first throttling device is controlled to maintain the first preset opening so that the high-temperature and high-pressure superheated gas and internal lubricating oil in the second water-cooled heat exchanger are removed from the second water-cooled heat exchanger. When the difference between the high pressure and the intake pressure meets the preset switching conditions, the control valve opens the first pipeline and disconnects the second pipeline.

8. The heat pump unit according to claim 1, characterized in that, include: The subcooler is configured as follows: When the heat pump unit is in the first cooling mode, the subcooler is connected between the second water-cooled heat exchanger and the first water-cooled heat exchanger to cool the refrigerant flowing out of the second water-cooled heat exchanger. When the heat pump unit is in heating mode, the subcooler is connected between the first water-cooled heat exchanger and the air-side heat exchanger to cool the refrigerant flowing out of the first water-cooled heat exchanger.

9. The heat pump unit according to claim 8, characterized in that, The subcooler is configured with a refrigerant flow path through which the refrigerant flows, having an inlet and an outlet. The heat pump unit includes: a main connecting pipe, which is connected to the first pipe and the second pipe; A first connecting pipe is connected to the main connecting pipe and the inlet, and a first control valve is provided on the first connecting pipe; A second connecting pipe is connected between the first water-cooled heat exchanger and the outlet section, and a second control valve is provided on the second connecting pipe.

10. The heat pump unit according to claim 2, characterized in that, When the heat pump unit is in heating mode, a heating circulation loop is formed between the compressor, the first water-cooled heat exchanger, the air-side heat exchanger, the four-way valve, and the gas-liquid separator. The control valve includes: The first valve is used to control the opening and closing of the first pipeline; The second valve is used to control the opening and closing of the second pipeline; During refrigeration operation, the first valve is closed and the second valve is open. When heating is in operation, the first valve is open and the second valve is closed.

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