Heat pump unit

Abstract

The invention discloses a heat pump unit which comprises a compressor, a first water-cooling heat exchanger and a first throttling device. The air side heat exchanger is connected to the first pipeline; the second water-cooling heat exchanger is connected with the second pipeline in parallel; a detection assembly; in the first refrigeration mode, the first pipeline is disconnected, and the second pipeline is connected; the controller is configured to control the compressor, the first water-cooling heat exchanger, the first throttling device and the air side heat exchanger to form a flow path before the unit enters a first refrigeration mode; the opening degree of a first throttling device and starting and stopping of a fan are controlled according to the target superheat degree range and the target exhaust temperature range; when the running time, the exhaust temperature and the suction pressure of the first throttling device reach a first preset condition, the compressor and the fan are controlled to stop; and when it is obtained that the difference between the high pressure and the suction pressure meets the preset switching condition, the first pipeline is disconnected, and the second pipeline is connected. The unit can release the stored refrigerant which is not used into the system, and reliable operation of the system is guaranteed.

Description

Technical Field

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

[0002] Although air-cooled heat pump chillers are flexible in application and suitable for most outdoor occasions, their energy efficiency under refrigeration conditions is lower than that of water-cooled chillers; although water-cooled heat pump chillers have high refrigeration efficiency, they require additional heat sources for heating, and their application scenarios are limited.

[0003] In order to improve the cooling and heating energy efficiency of air-cooled heat pump chillers at the same time, some manufacturers have begun to launch dual-cold source heat pump chillers, that is, units that combine water cooling and air cooling. Under the premise of ensuring heating performance, during cooling operation, the cooling energy efficiency of the unit is improved by changing the air-cooled heat exchange during cooling operation to water-cooled heat exchange, thereby ensuring that the unit has higher energy efficiency in the cooling state.

[0004] Different from the traditional multi-split heat pump unit, which needs to confirm the final refrigerant charge according to the type, number and length of the indoor units on site (generally the refrigerant and lubricating oil charge is large), the evaporator and condenser of the dual-cold source heat pump chiller are integrated inside the outdoor unit, the heat exchanger volume is fixed and the connecting pipes between different parts inside the whole machine are short. Therefore, the refrigerant charge of the whole unit is small and fixed.

[0005] When the dual-cold source heat pump chiller operates in different modes, because the total refrigerant and lubricating oil charge is small, if part of the refrigerant and lubricating oil is stored in the unused heat exchanger due to improper distribution, 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] In order to avoid the above problems, some manufacturers will charge additional refrigerant and lubricant, but charging too much refrigerant and lubricant will lead to poor energy efficiency of the whole unit. At the same time, if the operating system is charged with too much refrigerant, it will also cause the unit to continuously close the main throttling device, i.e. the electronic expansion valve, resulting in excessive exhaust pressure, affecting the reliability of the whole machine. Therefore, in the short-pipe multi-form heat exchanger of the dual-cold source heat pump chiller, how to ensure that the limited refrigerant and lubricant are always kept in the system required for operation at the appropriate refrigerant and lubricant filling amount is an important problem that needs to be solved at present. Summary of the invention

[0007] In view of the above technical problems pointed out in the background technology, a dual-cold source heat pump unit is proposed. When the unit is in refrigeration operation, the unused stored refrigerant can be released into the system to ensure the reliable and stable operation of the entire system.

[0008] In some embodiments of the present application, a heat pump unit is provided, comprising:

[0009] A 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 group comprises:

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

[0012] A fan is arranged at the air side heat exchanger side and is used to drive the air flow of the air side heat exchanger;

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

[0014] A control valve component, arranged on the first pipeline and the second pipeline;

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

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

[0017] The controller is configured to:

[0018] The superheat degree of the air side heat exchanger is obtained according to the air side heat exchanger temperature and high pressure pressure detected by the detection component;

[0019] When the heat pump unit is in the first cooling mode, the control valve is controlled so that the first pipeline is disconnected and the second pipeline is connected;

[0020] Before the heat pump unit enters the first cooling mode, the compressor is controlled to run, and the control valve is controlled to conduct 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 based on the target superheat range and the 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 it is obtained that the operation time of the first throttling device, the exhaust temperature and the suction pressure reach the first preset condition, the compressor and the fan are controlled to stop running, and the first throttling device is controlled to maintain a 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 suction pressure is obtained to meet the preset switching condition, the control valve is controlled to disconnect the first pipeline and connect the second pipeline.

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

[0025] The heat pump unit in this embodiment, before pre-starting the first refrigeration mode, first conducts the first pipeline to form a first refrigerant flow path between the first water-cooled heat exchanger of the air-side heat exchanger and the compressor. When the refrigerant flows in the first refrigerant flow path, the refrigerant in the air-side heat exchanger is converted into high-temperature and high-pressure superheated gas by controlling the first throttling device and the fan, and by controlling the compressor to stop and utilizing the pressure difference, the high-temperature and high-pressure superheated gas stored in the air-side heat exchanger is moved out of the air-side heat exchanger. Since the first refrigeration mode is running, the first water-cooled heat exchanger is used, so that the refrigerant can be moved out before the first refrigeration mode is running, and the refrigerant and lubricating oil of the entire unit will not be stored in the air-side heat exchanger that does not participate in the circulation, ensuring that the refrigerant and lubricating oil in the unit are fully used in the first refrigeration mode, avoiding a series of problems such as high system exhaust temperature, too low suction pressure, poor energy efficiency, and compressor wear caused by lack of refrigerant and compressor lubricating oil, ensuring that the entire unit always runs in the best control state, and improving the performance and operation stability of the unit.

[0026] In some embodiments of the present application, the controller is configured to: after the first throttling device operates at an initial first opening for a preset time, adjust the opening of the first throttling device and the start and stop status 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 pre-stores a first adjustment rule for controlling the opening of the first throttling device and the start and stop of the fan according to the superheat and exhaust temperature of the air side heat exchanger. During adjustment, the opening of the first throttling device and the start and stop of the fan can be adjusted and controlled according to the first adjustment rule based on the different acquired superheat values ​​of the air side heat exchanger and the exhaust temperature values, so that the actual superheat and exhaust temperature of the air side heat exchanger are infinitely close to the target superheat range and the target exhaust temperature range.

[0029] In some embodiments of the present 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, the first throttling device is controlled to increase its opening and the fan is controlled to start;

[0031] The 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, the first throttling device is controlled to increase its opening and the fan is controlled to stop;

[0032] The third rule: when it is obtained that the air side superheat is within the target superheat range and the exhaust temperature is within the target exhaust temperature range, the first throttling device is controlled to maintain the first opening and the fan is controlled to stop;

[0033] Fourth rule: when it is obtained that 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, the first throttling device is controlled to reduce the opening degree and the fan is controlled to stop;

[0034] The fifth rule: when it is obtained that the superheat of the air-side heat exchanger reaches the lower limit of the target superheat range, the first throttling device is controlled to increase the opening degree and the fan is controlled to stop;

[0035] Among them, the priorities of the first rule, the second rule, the third rule, the fourth rule and the fifth rule decrease in sequence;

[0036] The set upper limit temperature is greater than an upper limit value of the target exhaust gas 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, the opening of the first throttling device and the start and stop of the fan can be accurately controlled according to the above five rules, ensuring that the refrigerant in the air side heat exchanger can be converted into a superheated gas.

[0039] In some embodiments of the present application, the controller is configured to: after every preset time period, determine the rules that the superheat and exhaust temperature of the air side heat exchanger comply with according to the first rule to the fifth rule in sequence, and control the opening of the first throttling device and the start and stop of the fan according to the rules that they comply with.

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

[0041] The controller obtains the actual superheat and exhaust temperature of the air side heat exchanger after every preset time, and then determines which rule of the first to fifth rules the superheat and exhaust temperature of the air side heat exchanger meet in the order of the first to fifth rules. The opening of the first throttling device and the start and stop of the fan are controlled according to the rule that meets the rule to ensure the state of the refrigerant in the air side heat exchanger.

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

[0043] The operation time of the first throttling device reaches the upper limit of the set time threshold;

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

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

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

[0047] By detecting the running time of the starting phase, the exhaust temperature value or the suction pressure value, it can be used to accurately determine whether it is possible to enter the switching preparation phase.

[0048] In some embodiments of the present application, the preset switching condition includes:

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

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

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

[0052] When it is detected that the difference between the high pressure and suction pressure of the compressor is small, it can be determined that the refrigerant in the air-side heat exchanger has been basically completely removed;

[0053] When it is detected that the difference between the high pressure pressure and the suction pressure is slightly large but this difference has lasted for the preset switching time, it means that the pressure has stabilized and the refrigerant in the air side heat exchanger has been basically moved out.

[0054] Therefore, when the controller detects, if it is obtained that one of the first switching condition or the second switching condition is met, the first pipeline can be controlled to be disconnected and the second pipeline can be connected so that the unit enters the first cooling mode.

[0055] In some embodiments of the present application, the heat pump unit has a second refrigeration mode. When the heat pump unit is in the second refrigeration mode, the control valve controls the first pipeline to be connected and the second pipeline to be disconnected, so as to form a second refrigeration cycle 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 conduct 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 second water-cooled heat exchanger are controlled by taking the target superheat and the target exhaust temperature pre-stored in the controller as control targets, so that the refrigerant in the second water-cooled heat exchanger is converted into a high-temperature and high-pressure superheated gas;

[0059] When it is obtained that the operation time of the first throttling device, the exhaust temperature and the suction pressure meet the second preset condition, the compressor is controlled to stop running, the water pump on the second water-cooled heat exchanger is controlled to stop running, and the first throttling device is controlled to maintain a 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 suction pressure is obtained to meet the preset switching condition, the control valve is controlled to connect the first pipeline and disconnect the second pipeline.

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

[0062] The heat pump unit in this embodiment, before pre-starting the second refrigeration mode, first conducts the second pipeline 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 high-temperature and high-pressure superheated gas by controlling the first throttling device and the water pump on the second water-cooled heat exchanger side. The compressor is stopped by controlling the pressure difference to remove the high-temperature and high-pressure superheated gas stored in the second water-cooled heat exchanger from the second water-cooled heat exchanger. Since the air side heat exchanger is used when the second refrigeration 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 that does not participate in the circulation when the second refrigeration mode is running, so that the refrigerant and lubricating oil in the unit are fully used in the second refrigeration mode, avoiding a series of problems such as high system exhaust temperature, low suction pressure, poor energy efficiency, compressor wear, etc. caused by lack of refrigerant and compressor lubricating oil, ensuring that the entire unit always runs in the best control state, and improving the performance and operation stability of the unit.

[0063] In some embodiments of the present application, a subcooler is included, which is 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 a 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 setting 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, thereby further reducing the refrigerant temperature and achieving efficient 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, thereby achieving high-efficiency heating.

[0069] In some embodiments of the present application, the subcooler is configured with: a subcooler refrigerant flow path flowing through the interior thereof, which has an inlet portion and an outlet portion;

[0070] The heat pump unit includes: a main connecting pipeline connected to the first pipeline and the second pipeline;

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

[0072] The second connecting pipeline is connected between the first water-cooled heat exchanger and the outlet portion, and a second control valve is arranged on the second connecting pipeline.

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

[0074] By setting up the first connecting pipeline and the first control valve on the first connecting pipeline, the second connecting pipeline and the second control valve and the control valve components for switching the first pipeline and the second pipeline, when the unit is in the first refrigeration operation mode, the refrigerant can be limited to circulate along the compressor, the four-way valve, the first water-cooled heat exchanger and the second water-cooled heat exchanger to achieve an efficient refrigeration effect.

[0075] In some embodiments of the present 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 element comprises:

[0077] A first valve member, used for controlling the on-off of the first pipeline;

[0078] A second valve member, used for controlling the on-off of the second pipeline;

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

[0080] During heating operation, the first valve element is turned on and the second valve element is turned off.

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

[0082] By cooperating with the first control valve and the second control valve, the on-off control of the first pipeline and the second pipeline can be realized, so as to realize the selection of the air side heat exchanger and the second water-cooled heat exchanger participating in the circulation, so as to ensure the high energy efficiency of the heat pump unit for cooling or heating.

[0083] After reading the specific embodiments of the present invention in conjunction with the accompanying drawings, other features and advantages of the present invention will become more clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0085] Figure 1 This is a schematic structural diagram of an implementation scheme of a heat pump unit according to an embodiment;

[0086] Figure 2 is a schematic diagram of the flow of refrigerant when a heat pump unit according to an embodiment is in a first cooling mode;

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

[0088] Figure 4 A schematic structural diagram of an implementation manner of a heat pump unit according to an embodiment;

[0089] Figure 5 A schematic diagram of the refrigerant flow direction of a heat pump unit in a first refrigeration cycle mode according to an implementation mode of the embodiment;

[0090] Figure 6 A schematic diagram of the refrigerant flow direction of another implementation of the heat pump unit according to the embodiment in the first refrigeration cycle mode;

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

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

[0093] Fig. 9 A schematic structural diagram of a subcooler refrigerant flow path and a shunt flow path of a subcooler of a heat pump unit according to an embodiment;

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

[0095] Fig.11 is a control flow chart of the heat pump unit according to the embodiment when it is in the first cooling mode;

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

[0097] Fig.13 is a control flow chart of the heat pump unit according to the embodiment when it is in the second cooling mode;

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

[0099] Reference numerals:

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

[0101] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0102] In some embodiments of the present application, a heat pump unit is provided, referring to Figure 1 As shown, including:

[0103] The refrigerant circuit is formed by connecting a compressor 110, a first water-cooled heat exchanger 120, a second heat exchanger group, a first throttling device 510, a four-way valve 130 and a 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 is an electronic expansion valve.

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

[0106] The first hot water exchange pipeline is provided with a water pump for supplying water and driving the water to circulate in the first hot water exchange pipeline.

[0107] The second heat exchanger group comprises:

[0108] The air-side heat exchanger 150 is connected between the four-way valve 130 and the first water-cooled heat exchanger 120 through a first pipeline 180 .

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

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

[0111] The second heat exchanger group 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 through a second pipeline 190 .

[0112] The second water-cooled heat exchanger 160 is a second plate heat exchanger, in which refrigerant and water flow. 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 to flow by a water pump connected to the pipeline to accelerate the heat exchange between the water flow and the refrigerant in the second water-cooled heat exchanger.

[0114] When the unit is actually running, the air-side heat exchanger 150 or the second water-cooled heat exchanger 160 can be selectively turned on according to actual cooling or heating needs.

[0115] The heat pump unit has a controller, which communicates with the control valve 170 and is used to control the operation of the control valve 170. The control valve 170 is arranged on the first pipeline 180 and the second pipeline 190 and is used to control the on-off of the first pipeline 180 and the second pipeline 190.

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

[0117] In the first cooling mode, the controller controls the first pipeline 180 to be disconnected and the second pipeline 190 to be connected, forming a first refrigeration 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 flow process of the refrigerant in the first refrigeration mode is:

[0119] After coming out of the compressor 110, it enters the four-way valve 130, and then enters the second water-cooled heat exchanger 160 to exchange heat with the cooling water. The high-temperature and high-pressure gaseous refrigerant becomes a medium-temperature and medium-pressure liquid refrigerant, and enters the first water-cooled heat exchanger 120 through the filter. The refrigerant entering the second water-cooled heat exchanger 160 exchanges heat with the water flow in the second hot water exchange pipeline passing through it. The second hot water exchange pipeline can be a user-side water pipeline. The refrigerant entering the second water-cooled heat exchanger 160 for heat exchange is converted into a low-pressure and high-temperature gaseous refrigerant, and finally returns to the compressor 110 through the four-way valve 130 and the gas-liquid separator 140 to complete a refrigerant cycle.

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

[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 flow process of the refrigerant in heating mode is:

[0123] After coming out of the compressor 110, it enters the four-way valve 130, and then enters the first water-cooled heat exchanger 120 to exchange heat with the water pipe flowing through the inside of the device, that is, the user-side water source. The high-temperature and high-pressure gaseous refrigerant is converted into a medium-temperature and medium-pressure liquid refrigerant. After passing through the filter, it enters the air-side heat exchanger 150, and after heat exchange with the air, it is converted into 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 a heating refrigerant cycle.

[0124] During the entire heating cycle, the cooling heat exchange of the refrigerant is carried out through the first water-cooled heat exchanger 120 and the user-side water source, and the evaporative heat exchange is achieved through the air-side heat exchanger 150 and the air source. The air-cooled heat exchange method used for heating has a higher corresponding heating efficiency than the water-cooled heat exchange method, thereby achieving high-efficiency heating.

[0125] When the heat pump unit is structurally set, an air-side heat exchanger 150 and a second water-cooled heat exchanger 160 are arranged in parallel. When the unit is in refrigeration operation, the first pipeline 180 can be controlled to be closed, so that the second water-cooled heat exchanger 160 and the first water-cooled heat exchanger 120 cooperate to circulate the refrigerant for refrigeration. The refrigeration and heat exchange methods are all heat exchanged by water cooling, which is consistent with the heat exchange method of the water-cooled heat pump unit, thereby achieving high-efficiency refrigeration;

[0126] During heating, the second water-cooled heat exchanger 160 can be controlled not to participate in the circulation, and the air-side heat exchanger 150 and the first water-cooled heat exchanger 120 can be used in cooperation to make the refrigerant circulate 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, thereby realizing high-efficiency heating of the unit. The entire heat pump unit structure can take into account both cooling and heating, achieving high-efficiency cooling and heating effects.

[0127] In some embodiments of the present 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 and the suction pressure, including:

[0128] A temperature sensor is used to detect the heat exchange tube temperature Te of the air side heat exchanger;

[0129] The high-pressure pressure sensor is arranged on the exhaust side of the compressor and is used to detect the pressure on the high-pressure side to obtain the saturation temperature of the refrigerant. The high-pressure pressure is Pd, and the refrigerant saturation temperature Td_p corresponding to the high-pressure pressure Pd can be obtained through existing technology inspection.

[0130] The suction pressure sensor is installed 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 degree of the air side heat exchanger 150 is obtained based on the air side heat exchanger temperature and high pressure pressure detected by the detection component.

[0134] The superheat degree of the air side heat exchanger 150 is Tesh, then Tesh=Te-Td_p.

[0135] When the first refrigeration mode is started for the first time, three stages are required, namely the starting 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 migrated 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 gas state to facilitate the migration of the refrigerant and lubricating oil in the switching preparation phase.

[0137] During operation at this stage, according to the changes in the high pressure Pd during operation, the refrigerant saturation temperature Td_p corresponding to the high pressure Pd, the temperature Te of the air side heat exchanger 150 coil, the superheat Tesh (Tesh = Te-Td_p) of the air side heat exchanger 150, the exhaust temperature Td and the suction pressure value Ps, the coordinated action of the whole machine components will convert the refrigerant in the air side heat exchanger 150 into a high-temperature and high-pressure superheated gas to prepare for the secondary refrigerant distribution, avoid the unused air side heat exchanger 150 to store more lubricating oil and refrigerant, resulting in the lack of refrigerant and lubricating oil during operation of the unit, and improve the operating stability of the unit.

[0138] During the start-up phase, the controller controls the control valve to operate, so that the first pipeline 180 is connected, the second pipeline 190 is disconnected, and the compressor 110 is running.

[0139] A first refrigerant flow path is formed among 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 , the first water-side heat exchanger, and then flows back to the compressor 110 .

[0141] When the first refrigerant flow path is running, the controller controls the opening of the first throttling device 510 and the start and stop status of the fan based on the target superheat range and target exhaust temperature range pre-stored in the controller, 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, thereby ensuring that the refrigerant in the air side heat exchanger 150 is converted into high-temperature and high-pressure superheated gas.

[0142] The refrigerant stored in the air-side heat exchanger 150 is removed from the air-side heat exchanger 150, thereby ensuring that the amount of refrigerant and lubricating oil in the system is sufficient to meet the system operation requirements.

[0143] When it is obtained that the operating time of the first throttling device 510, the exhaust temperature and the intake pressure reach the first preset condition, the controller will end the control of the activation phase and enter the switching preparation phase.

[0144] The first preset condition is a condition for determining whether the start-up phase control is terminated.

[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 a 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] Among them, the first preset opening is the fully open opening of the first throttling device.

[0147] In the switching preparation stage, 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 the high and low pressure difference. At the same time, the lubricating oil stored in the fin heat exchanger can also be transferred from the air side heat exchanger together with the refrigerant under the action of the pressure difference and enter the unit to participate in the circulation.

[0148] After the switching preparation stage control, it is determined whether the refrigerant and the lubricating oil in the air-side heat exchanger 150 have been removed by detecting the high pressure pressure and the suction pressure.

[0149] When the difference between the high pressure and the suction pressure is found to meet the preset switching condition, the unit can be controlled to enter the normal operation stage of the first refrigeration mode.

[0150] The preset switching condition is a condition for determining whether the refrigerant and the lubricating oil in the air-side heat exchanger 150 are completely removed.

[0151] After the heat pump unit enters the normal operation stage, the control valve 170 can be controlled by the controller to disconnect the first pipeline 180 and connect the second pipeline 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 operation is not the first start-up, there is no need to go through the two stages of starting and switching preparation, and the system 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 migrate out of the air-side heat exchanger 150.

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

[0157] The heat pump unit in this embodiment, before pre-starting the first cooling mode, first opens the first pipeline 180 to form a first refrigerant flow path between the first water-cooled heat exchanger 120 of the air side heat exchanger 150 and the compressor 110. 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, and 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 controlling the compressor 110 to stop and utilizing the pressure difference.

[0158] Since the first water-cooled heat exchanger 120 is used when the first refrigeration 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 that does not participate in the circulation when the first refrigeration mode is running, thereby ensuring that the refrigerant and lubricating oil in the unit are fully used in the first refrigeration mode.

[0159] By using the above-mentioned control method that can remove the refrigerant and lubricating oil from the unused heat exchanger, there is no need to over-fill the refrigerant in the entire heat pump unit. It is only necessary to fill the unit with an appropriate amount of refrigerant and lubricating oil. When in use, the refrigerant and lubricating oil can always be migrated to the refrigerant flow path in operation through the above-mentioned control, avoiding the storage of refrigerant and lubricating oil in the non-operating heat exchanger, avoiding a series of problems such as high system exhaust temperature, low suction pressure, poor energy efficiency, and wear of compressor 110 caused by lack of refrigerant and compressor 110 lubricating oil, thereby ensuring that the entire unit always operates in the best control state and improving the performance and operating stability of the unit.

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

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

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

[0163] During the starting phase of the unit, within T_s1 seconds, the controller controls the opening of the first throttling device 510 to maintain the opening of Ev_s_by, and controls the fan to stop while the compressor 110 runs. After the unit has been running for T_s1 seconds, the opening of the first throttling device 510 and the fan are controlled according to the target superheat range and the target exhaust 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 and stop of the fan, the heat exchange effect of the air-side heat exchanger 150 can be changed, thereby changing the state of the refrigerant in the air-side heat exchanger 150.

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

[0165] 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 150, and a first adjustment rule for controlling the opening of the first throttling device 510 and the start and stop of the fan according to the superheat and exhaust 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 and stop of the fan can be adjusted and controlled according to the first adjustment rule based on the different superheat values ​​and exhaust temperature values ​​of the air side heat exchanger 150 obtained, so that the actual superheat and exhaust temperature of the air side heat exchanger 150 are infinitely close to the target superheat range and target exhaust 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, so as to facilitate its removal from the air side heat exchanger 150.

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

[0167] The target exhaust gas temperature range is blower<Td<bmiddle, and the upper limit temperature is set to bupper.

[0168] Reference Fig.13 As shown, the first adjustment rule includes:

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

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

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

[0172] The first regulation rule includes: The second rule: when the superheat of the air side heat exchanger 150 is within the target superheat range and the exhaust temperature reaches the upper limit of the target exhaust temperature range, the first throttling device 510 is controlled to increase its opening and the fan is controlled to stop.

[0173] That is, when the following conditions are satisfied: Tesh≥a and Td≥b, the first throttling device 510 is controlled to increase the first preset opening degree based on the original opening degree.

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

[0175] The first adjustment rule includes: the third rule: when it is obtained that the air side superheat is within the target superheat range and the exhaust temperature is within the target exhaust temperature range, the first throttling device 510 is controlled to maintain the first opening operation and the fan is controlled to stop.

[0176] That is, when Tesh≥a and Td≥b is satisfied, the first throttling device 510 can be kept at the initial opening.

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

[0178] The first regulation rule includes a fourth rule: when it is obtained that 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, the first throttling device 510 is controlled to reduce the opening and the fan is controlled to stop.

[0179] That is, when Tesh≥a and Td<b is satisfied, the first throttling device 510 is controlled to reduce the first preset opening degree based on 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 means that the exhaust temperature is too low. At this time, the exhaust temperature can be increased by closing the opening of the first throttling device 510 to make it close to the target exhaust temperature range.

[0181] Fifth rule: when it is obtained that the superheat of the air-side heat exchanger 150 reaches the lower limit of the target superheat range, the first throttling device 510 is controlled to increase its opening degree and the fan is controlled to stop.

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

[0183] Among them, the priorities of the first rule, the second rule, the third rule, the fourth rule and the fifth rule decrease in sequence;

[0184] The set upper limit temperature is greater than an upper limit value of the target exhaust gas 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, the opening of the first throttling device 510 and the start and stop of the fan can be accurately controlled according to the above five rules, thereby ensuring that the refrigerant in the air side heat exchanger 150 can be converted into a superheated gas.

[0187] In some embodiments of the present application, the controller is configured to: after every preset time period, determine the rules that the superheat and exhaust temperature of the air side heat exchanger 150 comply with according to the first rule to the fifth rule in sequence, and control the opening of the first throttling device 510 and the start and stop of the fan according to the rules that they comply with.

[0188] The preset time is tj seconds.

[0189] The controller obtains the actual superheat and exhaust temperature of the air side heat exchanger 150 after every preset time, and then makes a judgment in the order of the first rule to the fifth rule to determine which rule of the first rule to the fifth rule the superheat and exhaust temperature of the air side heat exchanger 150 comply with. The opening of the first throttling device 510 and the start and stop of the fan are controlled according to the rule that it complies with.

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

[0191] Reference Fig.12As shown, the control method for the unit to operate in the first refrigeration mode includes the following steps:

[0192] S110: During the start-up phase T_s1 seconds, the first throttling device 510 is maintained at the opening degree Ev_s_by, the fan is stopped, the compressor is running, 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 degree and exhaust temperature of the air side heat exchanger 150 are judged according to the first to fifth rules every tj seconds, and the opening degree of the first throttling device 510 and the start and stop state of the fan are adjusted;

[0194] S130: Do the operating time of the first throttling device 510, the exhaust gas temperature and the intake pressure meet the first preset condition?

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

[0196] S140: If the first preset condition is met, entering the handover preparation phase;

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

[0198] S160: When the preset switching condition is met, the control enters the first cooling mode.

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

[0200] The operation time of the first throttling device 510 reaches the upper limit of the set time threshold, wherein the set time threshold is: T_s1+T_s2, and the operation time of the first throttling device 510 is the continuous operation time of the corresponding starting phase.

[0201] Alternatively, the exhaust temperature reaches an upper limit of the exhaust temperature threshold, that is, the exhaust temperature exceeds or is equal to the exhaust temperature threshold, and the exhaust temperature threshold is Td_max°C.

[0202] Alternatively, the inhalation pressure reaches the lower limit of the inhalation pressure threshold, that is, the inhalation pressure is less than or equal to the inhalation pressure threshold, and the inhalation pressure threshold is Ps_min Mpa.

[0203] When the controller detects that any one of the running time, exhaust temperature value or suction pressure value of the starting phase meets the above conditions, it can jump out of the control of the starting phase and enter the switching preparation phase.

[0204] In some embodiments of the present application, the first preset condition also includes that the cumulative time of executing the first rule or the fifth rule reaches an upper limit value of the set cumulative time.

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

[0206] That is, the control of the start-up phase can be jumped if the accumulated time of executing the first rule or the accumulated time of the fifth rule is greater than or equal to T_start seconds.

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

[0208] For example, if the set cumulative time is 10S and the preset time is 2S, the controller controls the opening of the first throttling device 510 according to the first rule for the first time and lasts for 2S. After 2S, it makes another judgment. If it still meets the first rule, it continues to control the opening of the first throttling device 510 and the fan state according to the first rule and lasts for 2S. At this time, the cumulative execution time of the first rule is 4S, and it runs in a cycle in sequence. If the cumulative time of the first rule reaches 10S, the control of the starting stage is jumped.

[0209] In some embodiments of the present application, the preset switching condition includes:

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

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

[0212] Alternatively, the second switching condition: the difference between the high pressure and the suction pressure reaches the lower limit of the second switching threshold and the duration reaches the upper limit of the preset switching time, 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 smaller 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 may be 0.01, and the second switching threshold may be 0.1.

[0216] When it is detected that 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 substantially completely removed;

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

[0218] Therefore, when the controller detects, if it is obtained that one of the first switching condition or the second switching condition is met, the first pipeline 180 can be controlled to be disconnected and the second pipeline 190 can be connected so that the unit enters the first cooling mode.

[0219] In some embodiments of the present application, the heat pump unit has a second refrigeration mode. When the heat pump unit is in the second refrigeration mode, the controller controls the first pipeline 180 to be turned on and the second pipeline 190 to be turned off, thereby forming a second refrigeration 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 also replace the second water-cooled heat exchanger 160 to participate in the refrigeration cycle, thereby ensuring the reliable operation of the unit.

[0221] Reference Fig.11 As shown, when the second refrigeration mode is running, the refrigerant enters the four-way valve 130 after coming out of 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 pipeline through the first water-cooled heat exchanger 120. The refrigerant after heat exchange becomes a low-temperature and low-pressure gaseous refrigerant, and finally passes through the four-way valve 130 and the gas-liquid separator 140 and enters the compressor 110.

[0222] When the second cooling mode is started for the first time, three stages are also required, namely the starting stage, the switching preparation stage and the normal operation stage, which is the same as the operation of the first cooling mode mentioned above.

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

[0224] The first pipeline 180 is controlled to be disconnected, the second pipeline 190 is controlled to be connected, and the compressor 110 is running.

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

[0226] The opening degree of the first throttling device 510 and the start and stop of the water pump on the second water-cooled heat exchanger 160 are controlled with the target superheat and target exhaust temperature pre-stored in the controller as control targets, so that the refrigerant in the second water-cooled heat exchanger 160 is converted into 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 second water-cooled heat exchanger 160 side, the detected superheat and exhaust temperature of the air-side heat exchanger 150 can be made close to the target superheat range and target exhaust temperature range, thereby ensuring that the refrigerant in the air-side heat exchanger 150 is converted into high-temperature and high-pressure superheated gas.

[0228] When it is obtained that the operating time of the first throttling device 510, the exhaust temperature and the suction pressure meet the second preset condition, the compressor 110 is controlled to stop running and the water pump on the second water-cooled heat exchanger 160 is controlled to stop running, and the first throttling device 510 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 a condition for determining that the start-up phase control is terminated.

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

[0231] When the difference between the high pressure and the suction pressure is obtained to meet the preset switching condition, the control valve is controlled to connect the first pipeline 180 and disconnect the second pipeline 190 .

[0232] The preset switching condition is used to determine whether the refrigerant and lubricating oil in the second water-cooled heat exchanger 160 are completely removed. The preset switching condition for the second water-cooled heat exchanger 160 to enter the normal operation stage from the switching preparation stage is the same as that of the air-side heat exchanger 150, and will not be repeated here.

[0233] When the difference between the high pressure and the suction pressure is found to meet the preset switching condition, the unit can be controlled to enter the normal operation stage of the second refrigeration mode.

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

[0235] In the heat pump unit of the present embodiment, before pre-starting the second cooling mode, the second pipeline 190 is firstly 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 and high-pressure superheated gas by controlling the first throttling device 510 and the water pump on the second water-cooled heat exchanger 160 side. The high-temperature and high-pressure superheated gas stored in the second water-cooled heat exchanger 160 is removed from the second water-cooled heat exchanger 160 by controlling the compressor 110 to stop and utilizing the pressure difference. Since the air side heat exchanger 150 is utilized when the second cooling mode is in operation, it can be ensured that when the second cooling mode is in operation, 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, thereby ensuring that the refrigerant and lubricating oil in the unit are fully used in the second cooling mode.

[0236] By using the above-mentioned control method that can remove the refrigerant and lubricating oil from the unused heat exchanger, there is no need to over-fill the refrigerant in the entire heat pump unit. It is only necessary to fill the unit with an appropriate amount of refrigerant and lubricating oil. When in use, the refrigerant and lubricating oil can always be migrated to the refrigerant flow path in operation through the above-mentioned control, avoiding the storage of refrigerant and lubricating oil in the non-operating heat exchanger, avoiding a series of problems such as high system exhaust temperature, low suction pressure, poor energy efficiency, and wear of compressor 110 caused by lack of refrigerant and compressor 110 lubricating oil, thereby ensuring that the entire unit always operates in the best control state and improving the performance and operating stability of the unit.

[0237] In some embodiments of the present application, the controller is configured as follows: after the compressor 110 is turned on and the first throttling device 510 runs water cooling at an initial second opening for a preset time, 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 are adjusted 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 target exhaust temperature range.

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

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

[0240] The control method is the same. During the T_f1 second of the start-up phase of the unit, the controller controls the opening of the first throttling device 510 to maintain at the Ev_s_fl opening, and at the same time controls the water pump on the second water-cooled heat exchanger 160 to stop and the compressor 110 to run.

[0241] After the preset water cooling time, the opening degree of the first throttling device 510 and the start / stop state of the water pump on 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 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 blower<Td<bmiddle, and the upper limit temperature is set to bupper.

[0244] Reference Fig.14 As shown, the second adjustment rule includes:

[0245] Sixth rule: When the superheat of the second water-cooled heat exchanger 160 is within the target superheat range and the exhaust temperature reaches the upper limit of the set upper limit temperature, the first throttling device 510 is controlled to increase its opening and the water pump on the second water-cooled heat exchanger 160 is controlled to start.

[0246] That is, when TLsh≥a and Td≥b are satisfied, the first throttling device 510 is controlled to increase the third preset opening degree based on the original opening degree, wherein the third preset opening degree is: Ev_s_fl / E.

[0247] When the superheat meets the requirement and the exhaust temperature reaches the upper limit of the set upper limit temperature, it means that the exhaust temperature is too high. The exhaust temperature value can be quickly reduced by increasing the opening of the first throttling device 510 and turning on the water pump on the second water-cooled heat exchanger 160 to dissipate heat.

[0248] Seventh rule: When the superheat of the second water-cooled heat exchanger 160 is within the target superheat range and the exhaust temperature reaches the upper limit of the target exhaust temperature range, the first throttling device 510 is controlled to increase its opening and the water pump on the second water-cooled heat exchanger 160 is controlled to stop.

[0249] That is, when the following conditions are satisfied: TLsh≥a and Td≥b, the first throttling device 510 is controlled to increase the third preset opening degree based on the original opening degree.

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

[0251] Rule 8: When the superheat of the second water-cooled heat exchanger 160 is within the target superheat range and the exhaust temperature is within the target exhaust temperature range, the first throttling device 510 is controlled to maintain the second opening and the water pump on the second water-cooled heat exchanger 160 is controlled to stop.

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

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

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

[0255] 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 means that the exhaust temperature is too low. At this time, the exhaust temperature can be increased by closing the opening of the first throttling device 510 to make it close to the target exhaust temperature range.

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

[0257] That is, if TLsh≤a, the first throttling device 510 is controlled to increase the fourth preset opening on the basis of the original opening, wherein the fourth preset opening 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 order;

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

[0260] In some embodiments of the present application, the controller is configured to: after every preset time, determine the rules that the superheat and exhaust temperature of the second water-cooled heat exchanger 160 comply with according to the sixth to tenth rules in sequence, and control 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 rules they comply with.

[0261] After every preset time, the controller obtains the actual superheat and exhaust temperature of the second water-cooled heat exchanger 160, and then makes a judgment in the order of the sixth to tenth rules to determine which rule of the sixth to tenth rules the superheat and exhaust temperature of the second water-cooled heat exchanger 160 meets. 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 are controlled according to the rule that it meets.

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

[0263] Reference Fig.14 As shown, the control method for the unit to operate in the second refrigeration mode includes the following steps:

[0264] S210: During the start-up phase T_f1 seconds, the first throttling device 510 is maintained at an opening degree of Ev_s_fl, the water pump on the second water-cooled heat exchanger 160 is stopped, the compressor 110 is running, the first pipeline 180 is disconnected, and the second pipeline 190 is connected;

[0265] S220: Repeat the sixth to tenth rules to determine the superheat degree and exhaust temperature of the second water-cooled heat exchanger 160 and adjust the opening degree of the first throttling device 510 and the start / stop state of the water pump every tj seconds after T_f1 seconds;

[0266] S230: Do the operation time of the first throttling device 510, the exhaust gas temperature and the 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, entering the handover preparation phase;

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

[0270] S260: When the preset switching condition is met, the control enters the second cooling mode.

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

[0272] The operation time of the first throttling device 510 reaches the second set time, i.e., T_f1+T_f2 seconds;

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

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

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

[0276] In some embodiments of the present application, reference 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 6 , 7 As shown, when the first refrigeration mode is running, the refrigerant enters the second water-cooled heat exchanger 160 and exchanges heat with the water flow to change from a high-temperature and high-pressure gaseous refrigerant to a medium-temperature and medium-pressure liquid refrigerant, and then enters the subcooler 200 through a filter for heat exchange. The refrigerant after heat exchange in the subcooler 200 is cooled again, and after throttling and pressure reduction by the first throttling device 510 connected to the subcooler 200, the refrigerant changes from a medium-temperature and medium-pressure liquid to a low-temperature and low-pressure liquid refrigerant. The low-temperature and low-pressure liquid refrigerant then enters the first water-cooled heat exchanger 120, and then flows back to the compressor 110.

[0279] After the refrigerant flowing out of the second water-cooled heat exchanger 160 is supercooled by the supercooler 200, the temperature of the refrigerant is further reduced, thereby improving the refrigeration effect.

[0280] In some embodiments of the present application, the subcooler 200 is configured as follows: 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 to cool the refrigerant flowing out of the first water-cooled heat exchanger 120.

[0281] Reference Figure 8 , 9 As shown, when the heating mode is running, the refrigerant entering the first water-cooled heat exchanger 120 is changed from a high-temperature and high-pressure gaseous refrigerant to a medium-temperature and medium-pressure liquid refrigerant after heat exchange with the first water exchange water pipe flowing through the inside thereof, and then enters the subcooler 200 for heat exchange after passing through the filter. The refrigerant after heat exchange in the subcooler 200 is cooled again, and is throttled and reduced in pressure by the first throttling device 510 connected to the subcooler 200, and the refrigerant is changed from a medium-temperature and medium-pressure liquid to a low-temperature and low-pressure liquid refrigerant. The low-temperature and low-pressure liquid refrigerant enters the air side heat exchanger 150, and is changed into a low-pressure and high-temperature gaseous refrigerant after heat exchange with the air source, and finally returns to the compressor 110 through the four-way valve 130 and the gas-liquid separator 140.

[0282] After the refrigerant flowing out from the first water-cooled heat exchanger 120 is cooled by the supercooler 200, the temperature of the refrigerant is further reduced, thereby achieving heating in a low-temperature environment.

[0283] In some embodiments of the present 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.

[0284] In some embodiments of the present application, the subcooler 200 is configured with: a subcooler refrigerant flow path 210 flowing through the interior thereof, and the subcooler refrigerant flow path 210 has an inlet 211 and an outlet 212 .

[0285] The inlet portion 211 is an inlet for introducing refrigerant.

[0286] The outlet portion 212 is an outlet for leading the refrigerant out of the subcooler refrigerant flow path 210 .

[0287] The main connecting pipeline 300 is connected to the second water-cooled heat exchanger 160 and the air-side heat exchanger 150 .

[0288] The inlet portion 211 is closer to the main connecting pipeline 300 than the outlet portion 212 .

[0289] A first connecting pipeline 410 is connected to the main connecting pipeline 300 and the inlet 211 of the subcooler refrigerant flow path 210, and a first control valve 411 is provided on the first connecting pipeline 410;

[0290] The second connecting pipeline 420 is connected between the first water-cooled heat exchanger 120 and the outlet portion 212 of the subcooler refrigerant flow path 210 , and a second control valve 421 is provided on the second connecting pipeline 420 .

[0291] Reference Figure 4 As shown, when the first refrigeration mode is running, the refrigerant enters the four-way valve 130 after coming out of the compressor 110, and then enters the second water-cooled heat exchanger 160 to exchange heat with the cooling water. The high-temperature and high-pressure gaseous refrigerant is converted into a medium-temperature and medium-pressure liquid refrigerant. The refrigerant flows out of the second water-cooled heat exchanger 160 and enters the main connecting pipeline 300, flows from the main connecting pipeline 300 into the first connecting pipeline 410, enters the inlet 211 of the subcooler refrigerant flow path 210 from the first connecting pipeline 410, flows through the subcooler 200, flows out from the outlet 212, enters the second connecting pipeline 420, enters the first water-cooled heat exchanger 120 from the second connecting pipeline 420, and flows back to the compressor 110 from the first water-cooled heat exchanger 120 through the four-way valve 130 and the gas-liquid separator 140.

[0292] The first control valve 411 is a first one-way valve 620, which is used to limit the refrigerant flowing out of the main connecting pipeline 300 to flow along the first connecting pipeline 410;

[0293] The second control valve 421 is a second one-way valve 630, which is used to limit the refrigerant flowing out of the outlet portion 212 to flow into the first water-side heat exchanger.

[0294] By setting up the first connecting pipeline 410 and the first control valve 411 on the first connecting pipeline 410, the second connecting pipeline 420 and the second control valve 421 and the control valve component 170 for switching the first pipeline 180 and the second pipeline 190, when the unit is in the first refrigeration operation mode, the refrigerant can be limited to circulate along the compressor 110, the four-way valve 130, the first water-cooled heat exchanger 120 and the second water-cooled heat exchanger 160 to achieve an efficient refrigeration effect.

[0295] In some embodiments of the present application, the following are included:

[0296] A third connecting pipeline 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, and a third control valve 431 and a high-pressure liquid storage tank 432 are provided on the third connecting pipeline 430;

[0297] The fourth connecting pipeline 440 is connected to the outlet portion 212 of the subcooler refrigerant flow path 210 and the first connecting pipeline 410, and a fourth control valve 441 is provided on the fourth connecting pipeline 440;

[0298] The fifth control valve 450 is disposed between the connection point between the first pipeline and the main connecting pipeline and the connection point between 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 .

[0299] Reference Figure 8 As shown, when the heating mode is running, the refrigerant enters the four-way valve 130 after coming out of the compressor 110, and then enters the first water-cooled heat exchanger 120 to exchange heat with the cooling water. The high-temperature and high-pressure gaseous refrigerant is converted into a medium-temperature and medium-pressure liquid refrigerant. The refrigerant flows out of the first water-cooled heat exchanger 120 and enters the third connecting pipeline 430, and flows through the high-pressure liquid storage tank 432. The refrigerant flows out of the third connecting pipeline 430 and enters the refrigerant pipeline inlet 211 of the subcooler 200. After flowing through the subcooler 200, it flows out from the outlet 212 and enters the fourth connecting pipeline 440. From the fourth connecting pipeline 440, it enters the main connecting pipeline 300, and flows into the air side heat exchanger 150 from the main connecting pipeline 300. After the four-way valve 130 and the gas-liquid separator 140, it flows back to the compressor 110.

[0300] 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.

[0301] The third control valve 431 is a third one-way valve, which is used to limit the flow direction of the refrigerant in the third connecting pipeline 430 .

[0302] The fourth control valve 441 is a fourth one-way valve, which is used to limit the flow direction of the refrigerant flowing out of the outlet portion 212 in the fourth connecting pipeline 440 .

[0303] In some embodiments of the present application, the refrigerant flow direction defined by the first control valve 411 is opposite to the refrigerant flow direction defined by the third control valve 431 .

[0304] The first connecting pipeline 410 and the third connecting pipeline 430 are both connected to the inlet 211 of the subcooler refrigerant flow path 210 . The refrigerant flowing from the first connecting pipeline 410 to the inlet 211 will not flow into the third connecting pipeline 430 due to the flow direction limitation of the third control valve 431 .

[0305] Similarly, due to the flow direction limiting effect of the first control valve 411 , the refrigerant flowing from the third connecting pipeline 430 into the inlet portion 211 will not flow into the first connecting pipeline 410 .

[0306] The fifth control valve 450 is a fifth one-way valve, which is used to limit the refrigerant flowing into the main connecting pipeline 300 from flowing into the second water-cooled heat exchanger, thereby ensuring that the refrigerant can enter the air-side heat exchanger 150 .

[0307] By setting up the third connecting pipeline 430 and the third control valve 431, the fourth connecting pipeline 440, the fourth control valve 441 and the fifth control valve 450 on the third connecting pipeline 430 and cooperating with the control valve component 170 for switching the first pipeline 180 and the second pipeline 190, when the unit is in heating mode, the refrigerant can be limited to circulate along the compressor 110, the four-way valve 130, the first water-cooled heat exchanger 120 and the air-side heat exchanger 150 to achieve efficient heating effect.

[0308] Reference Figure 8 , Fig.10 As shown, in some embodiments of the present application, a first throttling device 510 is provided on the refrigerant flow path 210 of the subcooler near the outlet portion 212 , and the first throttling device 510 is a first electronic expansion valve.

[0309] The shunt flow path 220 has one end connected to the subcooler refrigerant flow path 210 between the first throttling device 510 and the subcooler 200, and one end connected to the subcooler 200. A second throttling device 520 is provided on the shunt flow path 220, and the second throttling device 520 is a second electronic expansion valve.

[0310] The compressor air supply circuit 230 has one end connected to the suction side of the compressor 110 and one end connected to the subcooler 200 .

[0311] The refrigerant flowing out through the first water-cooled heat exchanger 120 or the second water-cooled ventilator will flow through the subcooler refrigerant flow path 210. A 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 throttling and reducing the pressure by the second throttling device 520, it flows into the subcooler 200 again to exchange heat with the refrigerant in the subcooler refrigerant flow path 210 to further reduce the refrigerant temperature 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 air supply circuit 230.

[0312] The refrigerant flowing through the cooler refrigerant flow path 210 exchanges heat with the refrigerant that is diverted from the subcooler refrigerant flow path 210 and returns to the subcooler 200 after throttling by the second throttling device 520, which can further cool the refrigerant on the subcooler refrigerant flow path 210 and further reduce the temperature of the refrigerant.

[0313] In addition, the refrigerant after heat exchange in the subcooler enters the exhaust chamber of the compressor 110, which reduces the exhaust temperature of the compressor and thereby improves the heating capacity of the unit.

[0314] Reference Figure 7 As shown, in some embodiments of the present application, the air side heat exchanger 150 is connected to the main connecting pipeline 300 through the first pipeline 180;

[0315] Control valve assembly, including:

[0316] The electrically controlled valve 610 is a solenoid valve and is disposed on one side of the first pipeline 180 close to the main connecting pipeline 300;

[0317] A first one-way valve 620 is arranged on the first pipeline 180 between the air-side heat exchanger 150 and the electric control valve 610;

[0318] The second one-way valve 630 is connected in parallel to the first pipeline 180 where the first one-way valve 620 and the electric control valve 610 are arranged through a branch pipeline 181 , wherein the valve direction of the second one-way valve 630 is opposite to that of the first one-way valve 620 .

[0319] The electric control valve 610 and the first check valve 620 are matched to prevent the refrigerant of the air side heat exchanger 150 from leaking outward and flowing into the main connecting pipeline 300;

[0320] At the same time, the setting of 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, thereby preventing the refrigerant from being unable to circulate inside the air-side heat exchanger 150.

[0321] The first one-way valve 620, the second one-way valve 630 and the electric control valve 610 are used in combination to prevent the air side heat exchanger 150 from entering the refrigerant or the refrigerant from leaking. By using the existing simple valve body assembly, the production cost of the entire heat pump unit can be reduced.

[0322] Reference Figure 1-Figure 3 As shown, in some embodiments of the present application, the control valve member 170 includes:

[0323] A first valve member 171, used for controlling the opening and closing of the first pipeline 180;

[0324] A second valve member 172, used for controlling the opening and closing of the second pipeline 190;

[0325] During refrigeration operation, the first valve member 171 is closed and the second valve member 172 is open.

[0326] During heating operation, the first valve member 171 is turned on and the second valve member 172 is turned off.

[0327] The first valve member 171 is a two-way electric ball valve, and the second valve member 172 is a two-way electric ball valve.

[0328] The simple valve structure of the two-way electric ball valve can reduce the production cost of the entire heat pump unit.

[0329] In some embodiments of the present application, reference Figure 6 As shown, the control valve member 170 includes:

[0330] The first valve port is connected to the four-way valve 130 through a refrigerant pipeline;

[0331] The second valve port is connected to the first pipeline 180;

[0332] The third valve port is connected to the second pipeline 190;

[0333] During refrigeration operation, the first valve port portion and the second pipeline 190 are connected;

[0334] During the heating operation, the first valve port portion and the first pipeline 180 are in communication.

[0335] The control valve component 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, and the connection or disconnection of the first pipeline 180 and the second pipeline 190 can be controlled by switching the connection or disconnection between different valve ports of the three-way valve.

[0336] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A heat pump unit, characterized in that: Included are: A 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 group comprises: an air-side heat exchanger connected to the first pipeline between the four-way valve and the first water-cooled heat exchanger; A fan is arranged at the air side heat exchanger side and is used to drive the air flow of the air side heat exchanger; A second water-cooled heat exchanger is connected in parallel with the air-side heat exchanger through a second pipeline; A control valve component, arranged on the first pipeline and the second pipeline; A detection component for detecting the temperature of the air-side heat exchanger, the exhaust temperature, the high pressure and the suction pressure; The controller is configured to: When the heat pump unit is in the first cooling mode, the control valve is controlled so that the first pipeline is disconnected and the second pipeline is connected; The superheat degree of the air side heat exchanger is obtained according to the air side heat exchanger temperature and high pressure 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 conduct 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 based on the target superheat range and the 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 it is obtained that the operation time of the first throttling device, the exhaust temperature and the suction pressure reach the first preset condition, the compressor and the fan are controlled to stop running, and the first throttling device is controlled to maintain a 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 suction pressure is obtained to meet the preset switching condition, the control valve is controlled to disconnect the first pipeline and connect the second pipeline.

2. The heat pump unit according to claim 1, characterized in that: The controller is configured to: after the first throttling device runs at an initial first opening for a preset time, adjust the opening of the first throttling device and the start and 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.

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, the first throttling device is controlled to increase its opening and the fan is controlled to start; The 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, the first throttling device is controlled to increase its opening and the fan is controlled to stop; The third rule: when it is obtained that 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, the first throttling device is controlled to maintain the first opening and the fan is controlled to stop; Fourth rule: when it is obtained that 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, the first throttling device is controlled to reduce the opening degree and the fan is controlled to stop; The fifth rule: when it is obtained that the superheat of the air-side heat exchanger reaches the lower limit of the target superheat range, the first throttling device is controlled to increase the opening degree and the fan is controlled to stop; Among them, the priorities of the first rule, the second rule, the third rule, the fourth rule and the fifth rule decrease in sequence; The set upper limit temperature is greater than an upper limit value of the target exhaust gas temperature range.

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

5. The heat pump unit according to claim 4, characterized in that: The first preset condition at least includes: The operation time of the first throttling device reaches the upper limit of the set time threshold; Alternatively, the exhaust temperature reaches an upper limit of the exhaust temperature threshold; Alternatively, the inspiratory pressure reaches the lower limit value of the inspiratory 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 suction pressure reaches the lower limit of the first switching threshold; Alternatively, the second switching condition: the difference between the high pressure and the suction pressure reaches the lower limit of the second switching threshold and the duration is greater than the switching preset time; Among them, the first switching threshold is smaller than the second switching threshold.

7. The heat pump unit according to claim 1, characterized in that: The heat pump unit has a second refrigeration mode. When the heat pump unit is in the second refrigeration mode, the control valve controls the first pipeline to be connected and the second pipeline to be disconnected, so as to form a second refrigeration cycle between the compressor, the four-way valve, the air side heat exchanger, the first water-cooled heat exchanger and the 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 conduct 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 second water-cooled heat exchanger are controlled by taking the target superheat and the target exhaust temperature pre-stored in the controller as control targets, so that the refrigerant in the second water-cooled heat exchanger is converted into a high-temperature and high-pressure superheated gas; When it is obtained that the operation time of the first throttling device, the exhaust temperature and the suction pressure meet the second preset condition, the compressor is controlled to stop running, the water pump on the second water-cooled heat exchanger is controlled to stop running, and the first throttling device is controlled to maintain a 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 suction pressure is obtained to meet the preset switching condition, the control valve is controlled to connect the first pipeline and disconnect the second pipeline.

8. The heat pump unit according to claim 1, characterized in that: include: Subcooler, which is configured as: 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 a 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 provided with: a subcooler refrigerant flow path flowing through the interior thereof, which has an inlet portion and an outlet portion; The heat pump unit includes: a main connecting pipeline connected to the first pipeline and the second pipeline; a first connecting pipeline connected to the main connecting pipeline and the inlet portion, and a first control valve is provided on the first connecting pipeline; The second connecting pipeline is connected between the first water-cooled heat exchanger and the outlet portion, and a second control valve is arranged on the second connecting pipeline.

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 element comprises: A first valve member, used for controlling the on-off of the first pipeline; A second valve member, used for controlling the on-off of the second pipeline; During refrigeration operation, the first valve is closed and the second valve is open. During heating operation, the first valve element is turned on and the second valve element is turned off.

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