Cooling system, control method and heat pump unit

Abstract

A cooling system, a control method and a heat pump unit. The cooling system comprises a condenser (1), an evaporator (2), a subcooler (3) and a cooling pipe (4). The condenser (1) has a first outlet (11). The evaporator (2) has a second outlet (21). The subcooler (3) comprises a first flow channel (31) and a second flow channel (32), wherein an input end of the first flow channel (31) is in communication with the first outlet (11) of the condenser (1), and an input end of the second flow channel (32) is in communication with the second outlet (21) of the evaporator (2). The cooling pipe (4) comprises a first cooling pipe (41), wherein one end of the first cooling pipe (41) is connected to an output end of the first flow channel (31), and the other end of the first cooling pipe (41) is connected to a device to be cooled (110) of the heat pump unit.

Description

Cooling system, control method and heat pump unit

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese patent application No. 202410709952.4, filed on June 3, 2024, and entitled "Cooling system, control method and heat pump unit", the contents of which are hereby incorporated by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of heat pump units, and in particular to a cooling system, a control method and a heat pump unit. BACKGROUND

[0004] In the process of fully promoting the realization of the "double carbon" goal, China's energy structure will gradually change from coal-based to renewable energy-based low-carbon energy structure, and the energy chain of heat production will undergo a revolutionary change: from "fossil fuel heat production" to "electric heat production". As a renewable energy utilization device, heat pumps can improve low-grade heat energy to high-grade heat energy through electric energy or high-grade heat energy, achieving efficient heating. Under the same heating capacity, heat pump heating can reduce electricity consumption by 30%-85% compared to "electric direct heating", which is the most effective means to achieve low-carbon heat supply and conversion. At present, although medium-temperature heat pumps (MTHP) are widely used, the heat supply capacity of heat pumps under existing technical conditions is small, which is difficult to meet the demand for large temperature rise, large capacity and large-scale central heating.

[0005] Based on the widely distributed 30-60℃ waste heat resources in China, for the supply of 60-120℃ heat required by building heating and industrial production processes, through the development and utilization of heat pump technology, especially the research and application of compression heat pump technology with large capacity, high energy efficiency ratio and strong heat load adaptability, the waste heat utilization efficiency can be effectively improved, the use of ultra-high efficiency heat pump products in industrial waste heat recovery, central heating and other fields can be promoted, energy consumption and waste heat emission can be reduced, and the primary energy utilization rate in China can be effectively improved, which is of great significance for achieving the strategic goal of energy saving and emission reduction.

[0006] For industrial MW-level applications, high-temperature heat pump units with large capacity, large temperature rise and high energy efficiency have been developed, which face great challenges in system cooling and thermal management. The main challenges are as follows: when the system temperature rise reaches 60K or more, using the conventional condenser liquid taking throttling cooling method, the dryness after throttling is large, accounting for more than 55%, which leads to insufficient cooling liquid, making it difficult to cool the motor and lubricating oil of the unit. SUMMARY

[0007] The application aims to provide a cooling system, a control method and a heat pump unit, which can effectively solve the problem of insufficient cooling caused by large direct throttling superheat under large temperature difference.

[0008] To this end, in a first aspect, the application provides a cooling system, comprising a condenser, an evaporator, a subcooler and a cooling pipeline. The condenser has a first outlet. The evaporator has a second outlet. The subcooler comprises a first flow channel and a second flow channel, the input end of the first flow channel is in communication with the first outlet of the condenser, and the input end of the second flow channel is in communication with the second outlet of the evaporator; the cooling pipeline comprises a first cooling pipeline, one end of the first cooling pipeline is connected with the output end of the first flow channel, and the other end of the first cooling pipeline is connected with a cooled device of a heat pump unit.

[0009] In an embodiment, the evaporator and the second flow channel of the subcooler form a communication device, and the evaporator is arranged at a position higher than that of the subcooler.

[0010] In an embodiment, a first pipeline and a second pipeline are arranged between the evaporator and the subcooler, two ends of the first pipeline are in communication with the top of the evaporator and the top of the first flow channel respectively, and two ends of the second pipeline are in communication with the bottom of the evaporator and the bottom of the first flow channel respectively.

[0011] In an embodiment, the cooling system further comprises a gas return pipeline arranged between the cooled device and the evaporator and / or the second flow channel.

[0012] In an embodiment, a first electromagnetic valve is arranged between the condenser and the first flow channel, the cooling pipeline further comprises a second cooling pipeline, one end of the second cooling pipeline is connected with the output end of the second flow channel, and the other end of the second cooling pipeline is connected with the other end of the first cooling pipeline.

[0013] In an embodiment, a refrigerant pump and a first one-way valve with a flow direction pointing to the cooled device are arranged on the second cooling pipeline, and a second one-way valve with a flow direction pointing to the cooled device is arranged on the first cooling pipeline.

[0014] In an embodiment, the evaporator and the second flow channel are in communication through a communication pipeline, and the cooling system further comprises a second electromagnetic valve arranged on the communication pipeline.

[0015] In an embodiment, a second electromagnetic valve is arranged on the first pipeline and the second pipeline respectively. In an embodiment, the cooling pipeline further comprises a throttling assembly connected between the other end of the first cooling pipeline and the second cooling pipeline and the cooled device.

[0016] In an embodiment, the first flow channel of the subcooler is located inside the second flow channel.

[0017] In an embodiment, the first flow channel of the subcooler is a tube side, and the second flow channel of the subcooler is a shell side.

[0018] In a second aspect, the embodiments of the present application provide a control method of the cooling system, comprising: detecting a state of the compressor and determining whether the compressor is running normally; when the state of the compressor is normal running, the low-temperature refrigerant output by the evaporator enters the second flow channel of the subcooler and cools the high-temperature refrigerant in the first flow channel of the subcooler, and the high-temperature refrigerant in the first flow channel is cooled and then cools the cooled device through the cooling pipeline; when the state of the compressor is shutdown, the refrigerant in the second flow channel cools the cooled device through the second cooling pipeline.

[0019] In an embodiment, the cooling pipeline further comprises a refrigerant pump arranged on the second cooling pipeline, and the control method further comprises: detecting a shutdown duration of the compressor, and when the shutdown duration of the compressor is greater than or equal to a first duration, the refrigerant pump is turned off.

[0020] In a third aspect, the embodiments of the present application provide a heat pump unit, comprising: a cooled device; and the cooling system described above, which is used to cool the cooled device.

[0021] In an embodiment, the cooled device comprises a motor and a heat exchanger; and the motor and the heat exchanger are connected in parallel to the cooling system.

[0022] According to the cooling system, the control method and the heat pump unit provided by the embodiments of the present application, the low-temperature refrigerant in the evaporator enters the second flow channel of the subcooler, the high-temperature refrigerant in the first flow channel of the subcooler is cooled by heat exchange, the refrigerant in the first flow channel is cooled and then cools the cooled device through the first cooling pipeline, and there is a large temperature difference between the high-temperature refrigerant in the first flow channel of the subcooler and the low-temperature refrigerant in the second flow channel, so that the subcooling effect is sufficient, and the problem of insufficient cooling due to large throttling dryness under large temperature difference can be effectively solved. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings, which are incorporated herein and constitute part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, those skilled in the art can obtain other drawings from these drawings without any creative effort.

[0025] One or more embodiments are exemplarily illustrated by pictures in the drawings corresponding thereto, and these exemplary illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, unless otherwise specified. The drawings do not constitute a proportional limitation.

[0026] Fig. 1 shows a schematic diagram of a cooling system according to an embodiment of the present application;

[0027] Fig. 2 shows a schematic diagram of another cooling system according to an embodiment of the present application;

[0028] Fig. 3 shows a schematic diagram of still another cooling system according to an embodiment of the present application;

[0029] Fig. 4 shows a flow chart of a cooling control method according to an embodiment of the present application.

[0030] Reference signs: 1, condenser; 11, first outlet; 2, evaporator; 21, second outlet; 3, subcooler; 31, first flow channel; 32, second flow channel; 4, cooling pipeline; 41, first cooling pipeline; 42, second cooling pipeline; 43, refrigerant pump; 44, first check valve; 45, throttling assembly; 46, second check valve; 5, first pipeline; 6, second pipeline; 7, return pipeline; 8, first electromagnetic valve; 9, second electromagnetic valve; 110, cooled device; 111, motor; 112, heat exchanger. DETAILED DESCRIPTION

[0031] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0032] The following disclosure provides many different embodiments, or examples, for implementing different structures of the embodiments of the present application. For the purpose of simplifying the disclosure of the embodiments of the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the embodiments of the present application. In addition, reference numerals and / or letters can be repeated in different examples in the embodiments of the present application. Such repetition is for the purpose of simplification and clarity, and does not indicate the relationship between the various embodiments and / or settings discussed.

[0033] For ease of description, spatial relative terms can be used herein to describe the relative position relationship or movement of one element or feature with respect to another element or feature as shown in the drawings, such as "inner", "outer", "inboard", "outboard", "under", "below", "on", "above", "front", "back", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the drawings. For example, if the device in the drawings is turned over or reversed, or the orientation of the device is changed, the indicative directions will also change accordingly, for example: the element described as "under" or "below" another element or feature will be subsequently oriented as "above" or "above" another element or feature. Therefore, the example term "below" can include both up and down positions. The device can be additionally oriented (rotated 90 degrees or in other directions) and the spatial relative relationship descriptors used herein are interpreted accordingly.

[0034] To solve the problems in the prior art, the application provides a cooling system, a control method and a heat pump unit, which can effectively solve the problem of insufficient cooling caused by large direct throttling superheat under large temperature difference.

[0035] Fig. 1 shows a schematic diagram of a cooling system provided by an embodiment of the application; Fig. 2 shows a schematic diagram of another cooling system provided by an embodiment of the application; and Fig. 3 shows a schematic diagram of still another cooling system provided by an embodiment of the application.

[0036] As shown in Figs. 1-3, the application provides a cooling system applied to a heat pump unit, which includes a condenser 1, an evaporator 2, a subcooler 3 and a cooling pipeline 4. The condenser 1 has a first outlet 11. The evaporator 2 has a second outlet 21. The subcooler 3 includes a first flow passage 31 and a second flow passage 32, the first flow passage 31 being in communication with the first outlet 11 of the condenser 1, and the second flow passage 32 being in communication with the second outlet 21 of the evaporator 2. The cooling pipeline 4 includes a first cooling pipeline 41, one end of the first cooling pipeline 41 being connected with an output end of the first flow passage 31, and the other end of the first cooling pipeline 41 being connected with a cooled device 110 of the heat pump unit.

[0037] In the working process of the heat pump unit of the present application, the refrigerant output from the first outlet 11 is high-temperature refrigerant, and the refrigerant output from the second outlet 21 is low-temperature refrigerant. The high-temperature refrigerant flowing through the first flow channel 31 and the low-temperature refrigerant flowing through the second flow channel 32 exchange heat with each other. The low-temperature refrigerant in the evaporator 2 enters the second flow channel 32 of the supercooler 3, and exchanges heat with the high-temperature refrigerant in the first flow channel 31 of the supercooler 3 to cool the high-temperature refrigerant. The refrigerant in the first flow channel 31 is cooled and then cools the cooled device 110 through the first cooling pipeline 41. There is a large temperature difference between the high-temperature refrigerant in the first flow channel 31 of the supercooler 3 and the low-temperature refrigerant in the second flow channel 32, and the supercooling effect is sufficient, which can effectively solve the problem of large throttling dryness and insufficient cooling under large temperature difference.

[0038] In related technologies, for industrial MW-level applications, high-temperature heat pump units with large capacity, large temperature rise and high energy efficiency are developed, which face great challenges in system cooling heat management. Mainly manifested in: when the system temperature rise reaches 60K or more, using the conventional condenser 1 liquid taking throttling cooling method, the dryness after throttling is large, reaching more than 55%, resulting in insufficient cooling liquid, and the cooling of the unit motor 111 and lubricating oil is difficult.

[0039] The embodiment of the present application can supercool the high-temperature and high-pressure liquid refrigerant output from the condenser 1 through the supercooler 3. Specifically, the high-temperature and high-pressure refrigerant in the condenser 1 enters the first flow channel 31 of the supercooler 3, and the low-temperature refrigerant in the evaporator 2 enters the second flow channel 32 of the supercooler 3. For a large temperature rise heat pump unit, there can be a temperature difference of about 60℃ between the high-temperature and high-pressure refrigerant output from the condenser 1 and the low-temperature refrigerant in the evaporator 2. The high-temperature and high-pressure refrigerant in the first flow channel 31 exchanges heat with the low-temperature refrigerant in the second flow channel 32, thereby supercooling the high-temperature and high-pressure refrigerant in the first flow channel 31. The supercooling effect of the refrigerant in the first flow channel 31 is obvious, which can effectively reduce the problem of large temperature difference between the evaporator 2 and the condenser 1, reduce the dryness of the refrigerant after throttling, thereby increase the cooling liquid volume, and ensure the cooling effect of the unit motor 111 and lubricating oil. Specifically, the larger the temperature difference (pressure difference), the greater the condensing pressure, and the greater the saturation liquid point enthalpy value of the condensing pressure. The enthalpy before and after throttling is equal, and the greater the enthalpy, the greater the dryness. The specific refrigeration principle is not described here.

[0040] In some embodiments, the evaporator 2 and the second flow channel 32 of the supercooler 3 form a communication device, and the evaporator 2 is arranged at a position higher than that of the supercooler 3.

[0041] In related technologies, when the compressor of the heat pump unit is normally running, a special pump body is needed to transport the refrigerant. The pump body itself has a certain energy consumption, and the pump body itself has a certain failure rate. When the pump body itself fails out of control, it will directly cause insufficient cooling, thereby causing the heat pump unit to need to be shut down for protection.

[0042] In the present application, a communication device is formed between the second flow channel 32 between the evaporator 2 and the subcooler 3, and the setting position of the evaporator 2 is higher than that of the subcooler 3, so that the low-temperature refrigerant in the evaporator 2 can flow into the second flow channel 32 of the subcooler 3 under the action of gravity to exchange heat with the high-temperature refrigerant of the first flow channel 31, the low-temperature refrigerant in the second flow channel 32 is warmed and partially becomes gaseous, and then returns to the evaporator 2 again, without the power of an external pump body, the delivery of the refrigerant can be realized, thereby reducing the energy consumption of the pump body, and effectively avoiding the problem of unit shutdown caused by pump body failure, and ensuring the reliability of the heat pump unit operation.

[0043] The circulation of the refrigerant of the heat pump unit is: evaporator 2→ compressor→ condenser 1→ throttling device→ evaporator 2, wherein the gaseous refrigerant enters the compressor from the evaporator 2, the compressor compresses the gaseous refrigerant into high-temperature and high-pressure refrigerant, the high-temperature and high-pressure refrigerant enters the condenser 1 to become high-temperature and high-pressure liquid refrigerant, and the high-temperature and high-pressure liquid refrigerant is throttled by the throttling device to cool and lower the temperature of the cooled device 110. Since the technical solution related to the technical problem to be solved by the present application is that the refrigerant cools the cooled device 110, the circulation relationship of the refrigerant in the compressor, the condenser 1 and the evaporator 2 is not shown.

[0044] Further, the first pipe 5 and the second pipe 6 are arranged between the evaporator 2 and the subcooler 3, the two ends of the first pipe 5 are respectively communicated with the top of the evaporator 2 and the top of the first flow channel 31, and the two ends of the second pipe 6 are respectively communicated with the bottom of the evaporator 2 and the bottom of the first flow channel 31.

[0045] In the present application, the evaporator 2 and the subcooler 3 are communicated by the first pipe 5 and the second pipe 6, and the setting position of the evaporator 2 is higher than that of the subcooler 3, so that the low-temperature refrigerant in the evaporator 2 can enter the second flow channel 32 of the subcooler 3 through the second pipe 6, and the gaseous refrigerant warmed in the second flow channel 32 can return to the evaporator 2 through the first pipe 5. Of course, the high-temperature and high-pressure refrigerant output by the compressor enters the condenser 1, the high-temperature and high-pressure refrigerant in the condenser 1 enters the first flow channel 31 of the subcooler 3 and is subcooled, and then cools and lowers the temperature of the cooled device 110 through the cooling pipe 4, specifically through the first cooling pipe 41 of the cooling pipe 4, and then returns to the compressor as gaseous refrigerant through the evaporator 2. The liquid level of the liquid refrigerant in the second flow channel 32 of the evaporator 2 and the subcooler 3 is the same, and the height of the liquid level can be controlled by the liquid level sensor and the electronic expansion valve. The electronic expansion valve is connected with the condenser 1 and the evaporator 2, the electronic expansion valve controls the liquid level of the condenser 1, and the liquid level of the condenser 1 is high, the liquid level of the evaporator 2 is low, and vice versa. Thus, the control of the liquid level of the refrigerant in the evaporator 2 is realized, the existence of the liquid level in the evaporator 2 is ensured, and the low-temperature liquid refrigerant at the bottom of the evaporator 2 can be taken without consuming any power.

[0046] In some embodiments, the cooling system further comprises a return gas pipeline 7, which is arranged between the cooling device 110 and the evaporator 2 and / or the second flow channel 32. During the operation of the heat pump unit, the gaseous refrigerant passing through the cooling device 110 can return to the evaporator 2 and / or the second flow channel 32 through the return gas pipeline 7.

[0047] In the present application, the refrigerant passes through the first cooling pipeline 41 of the cooling pipeline 4, and after cooling and cooling the cooling device 110, the gaseous refrigerant returns to the evaporator 2 and / or the second flow channel 32 through the return gas pipeline 7. When the compressor of the heat pump unit is in the running state, the gaseous refrigerant can return to the low-pressure side through the return gas pipeline 7, that is, return to the second flow channel 32 of the evaporator 2 and the subcooler 3 in the present application, to realize the circulation of the refrigerant.

[0048] Specifically, as shown in FIG. 1, the first return gas pipeline 7 communicates with the second flow channel 32. As shown in FIG. 2, the return gas pipeline 7 communicates with the evaporator 2.

[0049] In an embodiment, a first electromagnetic valve 8 is arranged between the condenser 1 and the first flow channel 31, and the cooling pipeline 4 further comprises a second cooling pipeline 42, one end of which is connected to the output end of the second flow channel 32, and the other end of the second cooling pipeline 42 is connected to the other end of the first cooling pipeline 41, and both are connected to the input end of the cooling device 110. The second cooling pipeline 42 is used to transport the low-temperature refrigerant in the second flow channel 32 to cool the cooling device 110 of the heat pump unit.

[0050] In the present application, the first electromagnetic valve 8 between the condenser 1 and the first flow channel 31 of the subcooler 3 can control the high-temperature refrigerant in the condenser 1 to enter the first flow channel 31. When the first electromagnetic valve 8 is opened, the high-temperature refrigerant in the condenser 1 can enter the first flow channel 31, and when the first electromagnetic valve 8 is closed, the high-temperature refrigerant in the condenser 1 cannot enter the first flow channel 31. When the compressor is running, the first electromagnetic valve 8 is in the open state, and the refrigerant is transported through the first cooling pipeline 41 to cool and cool the cooling device 110; when the compressor is stopped, the first electromagnetic valve 8 is in the closed state, and at this time, the refrigerant is transported through the second cooling pipeline 42 to cool and cool the cooling device 110.

[0051] In the related art, after the compressor of the heat pump unit stops, the evaporation and condensation pressures reach equilibrium, the evaporation temperature rises, and the system has no pressure difference, resulting in that the system has no cold source to provide, the mixed 120℃ condensation temperature and 60℃ evaporation temperature directly affect the temperature of the motor 111 winding, the temperature of the motor 111 winding quickly rises, and the unit cannot be started again in a short time due to the influence of the unit starting condition, directly affecting the industrial production use, and the high temperature seriously causes the motor 111 to demagnetize, greatly reducing the unit life and reliability.

[0052] In the specific operation of the heat pump unit of the present application, when the compressor is in normal operation, the first electromagnetic valve 8 is in an open state, so that the high-temperature and high-pressure refrigerant output by the compressor can enter the first flow channel 31 after entering the condenser 1, and after being supercooled in the first flow channel 31, the cooling device 110 is cooled by the first cooling pipeline 41 of the cooling pipeline 4. In the moment when the compressor stops, if the liquid from the condenser 1 is still used for supercooling and throttling cooling, since the unit has stopped, the evaporation and condensation pressures are the same, the refrigerant in the condenser 1 is mixed with the refrigerant in the evaporator 2, the evaporation pressure rises, and since the back pressure rises instantaneously, there is no cold source to provide in the system, which cannot guarantee the cooling of the motor 111. Therefore, when the unit controller detects that the compressor has stopped, the first electromagnetic valve 8 is closed to realize closed environment cold storage, and then the second cooling pipeline 42 is opened to continue cooling and cooling the cooling device 110 by the refrigerant in the second flow channel 32.

[0053] Further, in an embodiment of the present application, the second cooling pipeline 42 is provided with a refrigerant pump 43 and a first one-way valve 44 pointing to the cooling device 110, and the first cooling pipeline 41 is provided with a second one-way valve 46 pointing to the cooling device 110, to prevent the refrigerant in the second cooling pipeline 42 from returning to the first flow channel 31 of the supercooler 3 through the first cooling pipeline 41.

[0054] In the present application, since the pressure is lost after the compressor stops, the refrigerant pump 43 is arranged on the second cooling pipeline 42, at this time, the refrigerant in the second flow channel 32 of the supercooler 3 is extracted by the refrigerant pump 43 to forcibly drive the refrigerant circulation, so that the low-temperature refrigerant in the second flow channel 32 continues to cool the cooling device 110 through the second cooling pipeline 42, and after a period of time, the temperature of the cooling device 110 is ensured to be reduced to the required temperature, and then the first electromagnetic valve 8 and the refrigerant pump 43 are closed. The first one-way valve 44 can prevent the refrigerant from returning to the second flow channel 32 through the second cooling pipeline 42 and the refrigerant pump 43 when the refrigerant flows through the first cooling pipeline 41 to cool and cool the cooling device 110.

[0055] In some embodiments, the evaporator 2 and the second flow channel 32 are communicated through a communication pipeline, and the cooling system further comprises a second electromagnetic valve 9 arranged on the communication pipeline.

[0056] In the present application, the evaporator 2 and the second flow channel 32 are connected by a communication pipeline, specifically, the communication pipeline includes the first pipeline 5 and the second pipeline 6, and the second electromagnetic valve 9 is arranged on the first pipeline 5 and the second pipeline 6 respectively. At the moment when the compressor stops, the second electromagnetic valve 9 and the first electromagnetic valve 8 are closed at the same time, and after the first electromagnetic valve 8 is closed, the high-temperature liquid refrigerant in the condenser 1 cannot enter the first flow channel 31, the evaporator 2 is no longer connected with the supercooler 3, the refrigerant in the second flow channel 32 of the supercooler 3 maintains the evaporation pressure and temperature before the stop, and is not affected by the refrigerant in the first flow channel 31, so the temperature is relatively low, and the refrigerant with a relatively low temperature in the second flow channel 32 is pumped to the cooled device 110 after throttling by the refrigerant pump 43 to realize continuous cooling of the cooled device 110.

[0057] Specifically, in an embodiment of the present application, the cooled device 110 includes a motor 111 and a heat exchanger 112. The heat exchanger 112 cools and lowers the temperature of the lubricating oil in the unit, and of course can also include other cooled components. The motor 111 and the heat exchanger 112 are connected in parallel in the cooling system. The refrigerant in the cooling pipeline 4 is throttled to cool and lower the temperature of the lubricating oil and the motor 111 respectively. After stopping, the motor 111 is mainly cooled, the motor 111 is cooled, the service life and reliability of the motor 111 are improved, and the problem that the unit cannot start again for a short time is effectively avoided.

[0058] As shown in FIG. 3, in some embodiments, the cooling system further includes a gas return pipeline 7, and the gaseous refrigerant passing through the cooled device 110 returns to the second flow channel 32 through the gas return pipeline 7.

[0059] In the present application, after the refrigerant cools and lowers the temperature of the cooled device 110, the refrigerant itself is warmed and becomes low-pressure gaseous refrigerant, and then returns to the second flow channel 32 of the supercooler 3 through the gas return pipeline 7, and a circulating loop of the refrigerant is formed between the second flow channel 32, the second cooling pipeline 42, the cooled device 110 and the gas return pipeline 7, and the refrigerant stored in the second flow channel 32 can be used to cool the motor 111 in the cooled device 110.

[0060] In some embodiments, the cooling pipeline 4 further includes a throttling assembly 45, and the throttling assembly 45 is connected between the other end of the connection between the first cooling pipeline 41 and the second cooling pipeline 42 and the cooled device 110. The refrigerant in the first cooling pipeline 41 or the second cooling pipeline 42 is throttled by the throttling assembly 45 and then delivered to the cooled device 110.

[0061] In the present application, the first cooling pipeline 41 and the second cooling pipeline 42 deliver the refrigerant to the throttling assembly 45, and the refrigerant becomes low-temperature liquid refrigerant after throttling by the throttling assembly 45, and the low-temperature liquid refrigerant cools and lowers the temperature of the cooled device 110.

[0062] Specifically, in an embodiment of the present application, the cooled device 110 includes a motor 111 and a heat exchanger 112, the heat exchanger 112 cools and lowers the temperature of the lubricating oil, the number of throttle components 45 is two, one end of the two throttle components 45 is connected to the other end of the first cooling pipeline (41) and the second cooling pipeline (42), the other end of the two throttle components 45 is connected to the motor 111 and the heat exchanger 112 respectively, the two throttle components 45 respectively control the temperature reduction of the motor 111 and the heat exchanger 112, and control valves are respectively arranged on the two throttle components 45, so that the temperature reduction of the motor 111 and the heat exchanger 112 can be controlled through the control valves. Specifically, when the compressor is in a normal operating state, the two control valves are all opened, and the motor 111 and the lubricating oil are simultaneously cooled and lowered in temperature, and when the compressor is stopped, the motor 111 can be selected to be cooled and lowered in temperature, so as to ensure that the refrigerant stored in the second flow channel 32 can effectively lower the temperature of the motor 111.

[0063] In some embodiments, the first flow channel 31 of the supercooler 3 is located inside the second flow channel 32, so that the high-temperature refrigerant flowing through the first flow channel 31 and the low-temperature refrigerant of the second flow channel 32 exchange heat with each other. In an embodiment, the first flow channel 31 of the supercooler 3 is a tube pass, and the second flow channel 32 of the supercooler 3 is a shell pass, and the tube pass is located in the shell pass.

[0064] In the present application, the supercooler 3 adopts a tube-shell structure, the first flow channel 31 adopts a tube pass, and the second flow channel adopts a shell pass, so that more refrigerant can be stored, the temperature reduction effect of the refrigerant in the first flow channel 31 is ensured, and the cold storage capacity of the second flow channel 32 is ensured, so that the temperature reduction effect of the motor 111 after the compressor is stopped can be ensured.

[0065] The cooling system in the present application uses the principle of a communicating vessel to connect the evaporator 2 of the unit and the bottom of the supercooler 3 to the bottom, and the top to the top, without consuming any power, so as to obtain the low-temperature liquid refrigerant in the evaporator 2, and overcool the high-temperature liquid refrigerant in the condenser 1 in the tube pass of the supercooler 3. The temperature difference between the tube pass and the shell pass of the supercooler 3 is generally about 60°C, and the overcooling effect is sufficient, thereby solving the problem of insufficient cooling of large dryness under large temperature difference. In the instant of shutdown, a cold source can still be provided, the low-temperature liquid refrigerant stored in the shell pass of the supercooler 3 is throttled through the second cooling pipeline 42 in the cooling pipeline 4 to cool and lower the temperature of the cooled device 110, thereby ensuring the cooling effect of the motor 111, improving the service life and reliability of the motor 111, and effectively avoiding the problem that the unit cannot be started again in a short time.

[0066] FIG. 4 shows a flow block diagram of a cooling control method provided in an embodiment of the present application.

[0067] As shown in FIG. 4, the embodiment of the present application provides a control method of the cooling system, comprising steps S1-S3.

[0068] S1, detecting the state of the compressor and determining whether the compressor is running normally. When the state of the compressor is normal running, step S2 is performed; when the state of the compressor is shutdown, step S3 is performed.

[0069] S2, the low-temperature refrigerant output by the evaporator 2 enters the second flow channel 32 of the subcooler 3 and cools the high-temperature refrigerant in the first flow channel 31 of the subcooler 3, and the high-temperature refrigerant in the first flow channel 31 is cooled and then cools the cooled device 110 through the first cooling pipeline 41 of the cooling pipeline 4.

[0070] S3, the refrigerant in the second flow channel 32 cools the cooled device 110 through the second cooling pipeline 42.

[0071] In the present application, when the compressor of the heat pump unit is running normally, the low-temperature refrigerant in the evaporator 2 subcools the high-temperature refrigerant in the first flow channel 31 of the subcooler 3, and the high-temperature refrigerant in the first flow channel 31 is subcooled and then cools the cooled device 110 through the first cooling pipeline 41 of the cooling pipeline 4, thereby solving the problem of insufficient cooling of large cooling degree under large temperature difference.

[0072] At the moment when the compressor of the heat pump unit is shutdown, since the back pressure rises instantaneously, there is no cold source in the system to provide, and the motor 111 cannot be continuously cooled. Therefore, the refrigerant stored in the second flow channel 32 can be directly used for cooling the cooled device 110 through the second cooling pipeline 42, so as to ensure that the motor 111 can be continuously cooled after the unit is shutdown, and the cooling effect of the motor 111 is ensured after a period of time.

[0073] Specifically, at the moment when the unit is shutdown, the unit control detects that the compressor is shutdown, and then the communication between the subcooler 3 and the condenser 1 and the communication between the subcooler 3 and the evaporator 2 are closed, so that the second flow channel 32 of the subcooler 3 realizes a closed environment for cold storage, the refrigerant in the second flow channel 32 of the subcooler 3 maintains the evaporation pressure and evaporation temperature before shutdown, and the refrigerant is circulated by the refrigerant pump 43 on the second cooling pipeline 42, so that the refrigerant in the second flow channel 32 can cool the motor 111.

[0074] In some embodiments, the cooling pipeline 4 further comprises a refrigerant pump 43 arranged on the second cooling pipeline 42, and the control method further comprises step S4.

[0075] S4, detecting the shutdown duration of the compressor, and when the shutdown duration of the compressor is greater than or equal to a first duration, the refrigerant pump is closed.

[0076] In the present application, the refrigerant continuously cools and cools the motor 111 for a period of time when the compressor of the heat pump unit is stopped. After a period of time, for example, after the first period of time, the refrigerant pump 43 is closed, the communication between the condenser 1 and the supercooler 3 is opened, and the communication between the evaporator 2 and the supercooler 3 is opened, to avoid the supercooler 3 from being long-term gas, and to ensure the reliability of subsequent unit operation.

[0077] Specifically, the first period of time can be 5 minutes, that is, the second cooling pipeline 42 is closed after being delayed for 5 minutes after the unit is stopped.

[0078] The present application provides a heat pump unit, comprising: a cooled device 110; and the above-mentioned cooling system, the cooling system is used for cooling the cooled device 110.

[0079] Specifically, the heat pump unit further comprises a compressor, and the cooled device 110 can be a motor 111 and a lubricating oil heat exchanger 112 of the compressor. In normal operation, the compressor compresses the gaseous refrigerant into high-temperature and high-pressure gaseous refrigerant, and then the high-temperature and high-pressure gaseous refrigerant is condensed into high-temperature and high-pressure liquid refrigerant through the condenser 1. The high-temperature and high-pressure liquid refrigerant in the condenser 1 enters the first flow channel 31 of the supercooler 3, and the low-temperature liquid refrigerant in the evaporator 2 enters the second flow channel 32 of the supercooler 3 to supercool the high-temperature refrigerant in the first flow channel 31. The refrigerant in the first flow channel 31 is cooled after supercooling, passes through the first cooling pipeline 41 and is throttled, and then cools and cools the cooled device 110. The refrigerant is warmed by the cooled device 110, becomes gaseous refrigerant through the evaporator 2, and then enters the compressor, forming a cycle of the refrigerant. At the moment when the compressor is stopped, the condenser 1 is disconnected from the supercooler 3, and the evaporator 2 is disconnected from the supercooler 3, to ensure that the refrigerant stored in the second flow channel 32 of the supercooler 3 is the temperature of the refrigerant in the evaporator 2 at the time of stopping. Then, the second cooling pipeline 42 is closed, the refrigerant pump 43 is closed, the communication between the condenser 1 and the supercooler 3 is restored, and the communication between the evaporator 2 and the supercooler 3 is restored.

[0080] It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order

[0081] Although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first", "second", and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0082] The above summary of the only specific embodiments of the application enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A cooling system applied to a heat pump unit, characterized in that, The cooling system comprises: a condenser (1) having a first outlet (11); an evaporator (2) having a second outlet (21); a subcooler (3) comprising a first flow channel (31) and a second flow channel (32), an input end of the first flow channel (31) being communicated with the first outlet (11) of the condenser (1), and an input end of the second flow channel (32) being communicated with the second outlet (21) of the evaporator (2); and a cooling pipeline (4) comprising a first cooling pipeline (41), one end of the first cooling pipeline (41) being connected with an output end of the first flow channel (31), and the other end of the first cooling pipeline (41) being connected with a cooled device (110) of the heat pump unit.

2. The cooling system of claim 1, wherein, The evaporator (2) is communicated with the second flow channel (32) of the subcooler (3), and the evaporator (2) is arranged at a position higher than that of the subcooler (3).

3. The cooling system of claim 2, wherein, The evaporator (2) and the subcooler (3) are provided with a first pipeline (5) and a second pipeline (6), two ends of the first pipeline (5) being communicated with a top of the evaporator (2) and a top of the first flow channel (31) respectively, and two ends of the second pipeline (6) being communicated with a bottom of the evaporator (2) and a bottom of the first flow channel (31) respectively.

4. Cooling system according to any of claims 1-3, characterized in that The cooling system further comprises a return pipeline (7) arranged between the cooled device (110) and the evaporator (2) and / or the second flow channel (32).

5. Cooling system according to any of claims 1-4, characterized in that The condenser (1) and the first flow channel (31) are provided with a first electromagnetic valve (8), the cooling pipeline (4) further comprises a second cooling pipeline (42), one end of the second cooling pipeline (42) being connected with an output end of the second flow channel (32), and the other end of the second cooling pipeline (42) being connected with the other end of the first cooling pipeline (41).

6. The cooling system of claim 5, wherein, The second cooling pipeline (42) is provided with a refrigerant pump (43) and a first one-way valve (44) with a flow direction pointing to the cooled device (110), and the first cooling pipeline (41) is provided with a second one-way valve (46) with a flow direction pointing to the cooled device (110).

7. Cooling system according to any of claims 1-6, characterized in that The evaporator (2) and the second flow channel (32) are communicated through a communication pipeline, and the cooling system further comprises a second electromagnetic valve (9) arranged on the communication pipeline.

8. The cooling system of claim 3, wherein, A second electromagnetic valve (9) is arranged on the first pipeline (5) and the second pipeline (6) respectively.

9. Cooling system according to claim 5 or 6, characterized in that The cooling pipeline (4) further comprises a throttling assembly (45) connected between the other end of the first cooling pipeline (41) and the second cooling pipeline (42) and the cooled device (110).

10. Cooling system according to any of claims 1-9, characterized in that The first flow channel (31) of the subcooler (3) is located inside the second flow channel (32).

11. Cooling system according to any of claims 1-10, characterized in that The first flow channel (31) of the subcooler (3) is a tube side, and the second flow channel (32) of the subcooler (3) is a shell side.

12. A method of controlling a cooling system as claimed in any one of claims 1-11, characterized in that comprising: detecting a state of the compressor and determining whether the compressor is running normally; When the compressor is in normal operation, the low-temperature refrigerant output by the evaporator (2) enters the second flow channel (32) of the overcooler (3) and cools the high-temperature refrigerant in the first flow channel (31) of the overcooler (3), and the high-temperature refrigerant in the first flow channel (31) is cooled and then cools the cooled device (110) through the cooling pipeline (4); When the compressor is in shutdown, the refrigerant in the second flow channel (32) cools the cooled device (110) through the second cooling pipeline (42).

13. The control method according to claim 12, characterized by, The cooling pipeline (4) further comprises a refrigerant pump (43) arranged on the second cooling pipeline (42), and the control method further comprises: detecting the shutdown duration of the compressor, and closing the refrigerant pump when the shutdown duration of the compressor is greater than or equal to a first duration.

14. A heat pump unit, characterized by Comprise: a cooled device (110); and The cooling system according to any one of claims 1-10, wherein the cooling system is used to cool the cooled device (110).

15. The heat pump unit of claim 13, wherein, The cooled device (110) comprises a motor (111) and a heat exchanger (112); and the motor (111) and the heat exchanger (112) are connected in parallel to the cooling system.

Images