Refrigerant circulation system and defrosting control method thereof, and heat pump unit

Abstract

The application relates to a refrigerant circulation system and a defrosting control method thereof and a heat pump unit, relates to the defrosting application field of a temperature regulating device, and aims to provide a defrosting scheme without shutdown of the refrigerant circulation system. The main evaporator of the refrigerant circulation system comprises at least two main flow channels and at least two defrosting flow channels which are arranged in parallel, the main evaporator is provided with at least two heat exchange zones in a first direction, and one defrosting flow channel and at least one main flow channel are arranged in each heat exchange zone. The main circuit comprises a discharge end of a compressor, a condenser, a first throttler, at least two main flow channels and a suction end of the compressor which are cyclically communicated. The defrosting circuit comprises the discharge end of the compressor, a first electric control valve, at least two defrosting flow channels, a second throttler, a defrosting evaporator and the suction end of the compressor which are cyclically communicated. In the defrosting working condition, the main flow channels are in a conduction state, and the main heat exchanger is configured to make the defrosting flow channel in at least one heat exchange zone conduct between the discharge end of the compressor and the second throttler.

Description

Technical Field

[0001] This application relates to the field of defrosting application technology of temperature control devices, and in particular to a refrigerant circulation system and its defrosting control method, and a heat pump unit. Background Technology

[0002] When an air source heat pump system operates in a low-temperature, high-humidity environment during winter, frost is easily formed on the surface of the evaporator fins. The accumulation of frost can significantly increase airflow resistance and drastically reduce heat exchange efficiency, potentially leading to system shutdown for protection purposes.

[0003] Currently, the mainstream defrosting methods include reverse circulation defrosting and electric heating defrosting, but both have significant technical drawbacks. Reverse circulation defrosting achieves defrosting by switching the refrigerant flow direction, but indoor heating is interrupted during defrosting, significantly reducing user comfort. Furthermore, the four-way reversing valve is prone to jamming or internal leakage due to frequent switching under low temperature and high pressure differential conditions. Electric heating defrosting relies on resistance heating elements to directly heat the fins, resulting in low energy efficiency. Summary of the Invention

[0004] This application provides a refrigerant circulation system and its defrosting control method, as well as a heat pump unit, aiming to provide a non-stop defrosting solution for a refrigerant circulation system.

[0005] This application provides a refrigerant circulation system, including a main evaporator, a main circuit, and a defrost circuit. The main evaporator includes at least two main flow channels and at least two defrost flow channels arranged in parallel. The main evaporator has at least two heat exchange zones along a first direction, each heat exchange zone containing one defrost flow channel and at least one main flow channel. The main circuit includes a compressor discharge end, a condenser, a first expansion valve, at least two main flow channels, and a compressor suction end, all connected in a circulating manner. The defrost circuit includes a compressor discharge end, a first electrically controlled valve, at least two defrost flow channels, a second expansion valve, a defrost evaporator, and a compressor suction end, all connected in a circulating manner. During defrost operation, the main flow channels are in a conductive state, and the main heat exchanger is configured such that at least one defrost flow channel in one of its heat exchange zones is connected between the compressor discharge end and the second expansion valve.

[0006] In some embodiments, the main evaporator includes a control valve assembly, which includes at least two second electrically controlled valves, one of which is connected to a defrost channel for controlling the opening and closing of the defrost channel.

[0007] In some implementations, the number of first electrically controlled valves is at least two, and the at least two first electrically controlled valves are connected to a plurality of defrosting channels in a one-to-one correspondence.

[0008] In some embodiments, the main evaporator includes a control valve assembly comprising a valve body and a valve core. The valve body has a valve cavity and a liquid inlet and at least two liquid outlets connected thereto. One liquid outlet is connected to a defrosting channel, and the liquid inlet is connected to a first electrically controlled valve. The valve core is rotatably or slidably disposed within the valve cavity, and the valve core is configured to connect the liquid inlet and one of the liquid outlets.

[0009] In some embodiments, the defrosting circuit includes at least one of a third expansion valve and a first check valve. The third expansion valve is connected in series with the second expansion valve on the side away from the defrosting evaporator, and the second expansion valve is an electronic expansion valve. The first check valve is connected in series between the defrosting passage and the defrosting evaporator.

[0010] In some embodiments, the defrosting evaporator includes a first heat exchange channel and a second heat exchange channel that exchange heat with each other. In the defrosting circuit, the first heat exchange channel is connected in series between the compressor's suction end and the second expansion valve. The refrigerant circulation system includes a first heating branch, which includes a second one-way valve, a second heat exchange channel, and a third electrically controlled valve connected in series. In the main circuit for heating operation, at least a portion of the main circuit between the compressor's discharge end and the first expansion valve is connected in parallel with the first heating branch.

[0011] In some implementations, the defrosting evaporator is a plate heat exchanger or a shell-and-tube heat exchanger.

[0012] In some embodiments, the defrosting evaporator includes a first heat exchange channel and a third heat exchange channel that exchange heat with each other. In the defrosting circuit, the first heat exchange channel is connected in series between the compressor's suction end and a second expansion valve. The refrigerant circulation system includes a second heating branch, which includes a third check valve, a third heat exchange channel, and a fourth electrically controlled valve connected in series. In the defrosting circuit, at least a portion of the defrosting circuit between the compressor's discharge end and the defrosting channel is connected in parallel with the second heating branch.

[0013] In some implementations, the main evaporator is a finned heat exchanger.

[0014] In some implementations, the main circuit includes a cooling fan that drives airflow through the main evaporator; along the direction of airflow, the main flow path in the same heat exchange zone is located downstream of the defrosting flow path.

[0015] In some embodiments, the refrigerant circulation system includes a first temperature sensor, at least two second temperature sensors, a third temperature sensor, and a control module. The first temperature sensor is located at the compressor's exhaust end and is used to detect the exhaust temperature. The second temperature sensors are located in multiple heat exchange zones and are used to detect the heat exchange temperature in each zone. The third temperature sensor is used to detect the ambient temperature. The control module is electrically connected to the first, second, and third temperature sensors to acquire the exhaust temperature, multiple heat exchange temperatures, and the ambient temperature. The control module is also electrically connected to the compressor, a first expansion valve, a first electrically controlled valve, and a second expansion valve.

[0016] In a second aspect, embodiments of this application provide a defrosting control method for a refrigerant circulation system, used to control the refrigerant circulation system in the first aspect, the defrosting control method comprising: Control the refrigerant circulation system to start the main circuit and switch to heating mode.

[0017] Obtain the heat exchange temperature of multiple heat exchange zones in the main evaporator.

[0018] If the heat exchange temperature of at least a portion of the heat exchange zone is lower than the first threshold and the duration exceeds the first duration, that portion of the heat exchange zone is marked as the target area.

[0019] The defrosting circuit is activated to sequentially heat the heat exchange zones corresponding to the target area.

[0020] In some implementations, the heating sequence of the heat exchange zones corresponding to the target area is arranged in order of increasing heat exchange temperature.

[0021] In some implementations, the step of controlling the activation of the defrosting circuit to sequentially heat the heat exchange zone corresponding to the target area includes: The first electrically controlled valve is opened, and the defrosting channels corresponding to each heat exchange zone in the target area are sequentially opened.

[0022] In some embodiments, the second throttle is characterized by being an electronic expansion valve, and the step of controlling the start-up defrosting circuit to sequentially heat the heat exchange zone corresponding to the target area includes: Obtain the compressor's exhaust temperature and compare the exhaust temperature with the second threshold and the third threshold, where the second threshold is greater than the third threshold.

[0023] If the exhaust temperature is greater than the second threshold, the opening of the second throttle is increased by the first preset value.

[0024] If the exhaust temperature is less than the third threshold, the opening of the second throttle is reduced by the second preset value.

[0025] If the exhaust temperature is between the third threshold and the second threshold, when the exhaust temperature is greater than the target temperature, the opening of the second throttle is increased by the third preset value; when the exhaust temperature is less than the target temperature, the opening of the second throttle is decreased by the third preset value.

[0026] In some implementations, the step of controlling the start-up defrosting circuit to sequentially heat the heat exchange zone corresponding to the target area before obtaining the exhaust temperature includes: The ambient temperature is acquired, and the second throttle is switched to the corresponding initial opening based on the ambient temperature.

[0027] In some implementations, the step of controlling the activation of the defrosting circuit to sequentially heat the heat exchange zone corresponding to the target area includes: If the exhaust temperature is greater than the fourth threshold, and the fourth threshold is greater than the second threshold, the opening of the second throttle is switched to 100%, and the compressor's operating frequency is reduced; and / or, After defrosting of each heating zone corresponding to the target area is completed, the target areas are reconfirmed and sorted; and / or, If the heating temperature of the heated heat exchange zone is greater than or equal to the fifth threshold, and is maintained for the third duration, and the fifth threshold is greater than 0°C, then heating of the heat exchange zone is stopped; or... If the heating time of the heat exchange zone reaches the fourth duration, and the fourth duration is greater than 100 seconds, then heating of the heat exchange zone will stop.

[0028] In some implementations, the defrosting control method includes: Obtain the time interval between two adjacent heating conditions in the heat exchange zone.

[0029] The frosting rate is calculated based on multiple time intervals for each heat exchange zone, and the frosting rates of multiple heat exchange zones are compared.

[0030] If the frosting rate of the heat exchange zone exceeds the preset value, the heating priority or heating time of that heat exchange zone will be increased.

[0031] Thirdly, embodiments of this application provide a heat pump unit, including the refrigerant circulation system described in the first aspect.

[0032] The technical solutions provided in this application have the following advantages compared with the prior art: Through the configuration of the main circuit, defrost circuit, and the aforementioned main evaporator, the main flow path in the main evaporator remains open during defrost operation to ensure normal heat absorption and vaporization of the internal refrigerant, thus preventing shutdown during heating. Furthermore, the main evaporator is configured such that at least one defrost flow path in the heat exchange zone is connected between the compressor's exhaust end and the second expansion valve. Specifically, the defrost circuit is activated via the first electronically controlled valve, allowing a portion of the refrigerant to flow directly from the compressor to the defrost flow path. This causes the refrigerant to liquefy and release heat within the defrost flow path, thereby heating the main flow path in the heat exchange zone where the defrost flow path is located, enabling the main flow path to quickly complete defrosting.

[0033] During the defrosting process through the defrosting channels, the high-temperature, high-pressure gaseous refrigerant bypassing the compressor exhaust to the main evaporator only needs to flow through the defrosting channels in one of the heat exchange zones to liquefy and release heat. This concentrates the limited refrigerant heat to generate a higher heating temperature within a unit heat exchange zone, rapidly melting the frost on the outer wall of the main flow channel in that zone, thus improving the defrosting speed and effect. Subsequently, the defrosting channels in other heat exchange zones are sequentially switched to connect between the compressor and the second expansion joint, allowing for rapid defrosting of the main flow channels in the other heat exchange zones.

[0034] During the aforementioned defrosting process, the first heat exchange zone achieves rapid defrosting of the main flow path through concentrated heat. This allows for the rapid restoration of some of the main circuit's heating capacity without shutting down the main circuit, while maintaining a high energy efficiency ratio. Simultaneously, the presence of defrosting channels corresponding to the main flow path in each heat exchange zone not only increases the defrosting coverage of the main evaporator but also improves the uniformity of the defrosting channel coverage. This reduces the proportion of localized ice blockages and air blockages, improving the overall defrosting speed and effectiveness of the refrigerant circulation system. Furthermore, it effectively enhances the operational reliability, user comfort, and system energy efficiency ratio of the refrigerant circulation system in low-temperature, high-humidity environments. Attached Figure Description

[0035] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0036] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0038] Figure 1 This is a schematic diagram of the main evaporator provided in an embodiment of this application; Figure 2 This is a schematic diagram of a refrigerant circulation system provided in an embodiment of this application; Figure 3 A schematic diagram of a refrigerant circulation system provided in this application embodiment includes a main circuit, a defrosting circuit, a first heating branch, and a second heating branch; Figure 4 This is a schematic diagram of the structure of a control valve assembly provided in an embodiment of this application; Figure 5 for Figure 3 A schematic diagram of the overall structure of the corresponding refrigerant circulation system; Figure 6 for Figure 5 The diagram shows the structure of the main loop in the refrigerant circulation system. Figure 7 for Figure 3 A schematic diagram of a connection structure for the defrosting evaporator shown in the figure; Figure 8 An electrical connection diagram of a refrigerant circulation system provided in this application embodiment; Figure 9 A flowchart of a defrosting control method for a refrigerant circulation system provided in this application embodiment; Figure 10 This is a schematic diagram of the connection structure of a control module provided in an embodiment of this application.

[0039] Icon labels: 100. Main evaporator; 110. Main flow channel; 120. Defrosting flow channel; 130. Heat exchange zone; 140. Fins; 150. Control valve assembly; 151. Valve body; 152. Valve core; 153. Valve chamber; 154. Liquid inlet; 155. Liquid outlet; 156. Second electrically controlled valve; 160. First gas collecting pipe; 170. Second gas collecting pipe; 200. Main circuit; 210. Compressor; 211. 212. Exhaust end; 220. Intake end; 230. Condenser; 240. First throttle valve; 250. Four-way valve; 260. Radiator fan; 260. First gas-liquid separator; 300. Defrosting circuit; 310. First electrically controlled valve; 320. Second throttle valve; 330. Defrosting evaporator; 331. First heat exchange channel; 332. Second heat exchange channel; 333. Third heat exchange channel; 340. Third Throttling device; 350, First check valve; 360, Second gas-liquid separator; 400, First heating branch; 410, Third solenoid valve; 420, Second check valve; 500, Second heating branch; 510, Fourth solenoid valve; 520, Third check valve; 610, Control module; 611, Processor; 612, Communication interface; 613, Memory; 614, Communication bus; 620, First temperature sensor; 630, Second temperature sensor; 640, Third temperature sensor; K1, First threshold; K2, Second threshold; K3, Third threshold; K4, Fourth threshold; K5, Fifth threshold; T0, Target temperature; T1, First duration; T2, Second duration; T3, Third duration; T4, Fourth duration; A1, First preset value; A2, Second preset value; A3, Third preset value. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0042] For ease of description, spatial relative terms may be used in the text to describe the relative position or movement of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "front," "back," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure undergoes a positional flip, orientation change, or change of motion, these directional indications will change accordingly. For instance, an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0043] When an air source heat pump system operates in a low-temperature, high-humidity environment during winter, frost is easily formed on the surface of the evaporator fins. The accumulation of frost can significantly increase airflow resistance and drastically reduce heat exchange efficiency, potentially leading to system shutdown for protection purposes.

[0044] Currently, the mainstream defrosting methods include reverse circulation defrosting, electric heating defrosting, and hot gas bypass defrosting, but all of the above have obvious technical defects.

[0045] First, reverse circulation defrosting achieves defrosting by switching the refrigerant flow direction, but indoor heating is interrupted during defrosting, resulting in a significant decrease in user comfort. Furthermore, the four-way reversing valve is prone to jamming or internal leakage when frequently switching under low temperature and high pressure differential conditions.

[0046] Secondly, electric defrosting relies on resistance heating elements to directly heat the fins, resulting in low energy efficiency. Furthermore, the placement of the heating elements often leads to uneven defrosting.

[0047] While hot gas bypass defrosting can maintain continuous indoor heating, this solution has several technical bottlenecks: First, the limited bypass heat is insufficient to melt the frost layer on the entire evaporator surface simultaneously, resulting in low defrosting efficiency. Second, the defrosting coverage is uneven, and the far-end fin areas of the evaporator cannot obtain enough heat to form localized ice blockages.

[0048] Please see Figures 1 to 10 This application provides a refrigerant circulation system and its defrosting control method, a heat pump unit, and at least one non-stop defrosting solution for a refrigerant circulation system.

[0049] Firstly, such as Figure 1 and Figure 2As shown, this application provides a refrigerant circulation system, including a main evaporator 100, a main circuit 200, and a defrost circuit 300. The main evaporator 100 includes at least two main flow channels 110 and at least two defrost flow channels 120 arranged in parallel. The main evaporator 100 has at least two heat exchange zones 130 along a first direction, and each heat exchange zone 130 has a defrost flow channel 120 and at least one main flow channel 110.

[0050] The main evaporator 100 is a major heat exchange component in the refrigerant circulation system. Under heating and dehumidification conditions, the refrigerant absorbs external heat and evaporates in the main flow channel 110 of the main evaporator 100 to obtain thermal energy from the environment.

[0051] For example, the main evaporator 100 may employ a finned heat exchanger structure. For instance, along the height direction, the main evaporator 100 is divided into two, three, or more heat exchange zones 130. These heat exchange zones 130 can be defined by physical partitions within the main evaporator 100 or by piping grouping. Each heat exchange zone 130 includes at least one main flow channel 110 and at least one defrosting flow channel 120. If there are four heat exchange zones 130, the four heat exchange zones 130, four main flow channels 110, and four defrosting flow channels 120 are arranged in a one-to-one correspondence. The main flow channels 110 and defrosting flow channels 120 are arranged in an alternating or side-by-side manner within the corresponding heat exchange zones 130.

[0052] Alternatively, the main evaporator 100 may be configured to include a main flow channel 110 and a defrost flow channel 120, both of which are coil-type structures, with each defrost flow channel 120 arranged close to a main flow channel 110 to form a heat exchange zone; this is not limited.

[0053] Combination Figure 2 and Figure 6 The main circuit 200 includes the exhaust end 211 of the compressor 210, the condenser 220, the first throttling device 230, at least two main flow channels 110, and the suction end 212 of the compressor 210, all connected in a loop. The main circuit 200 is the main operating path of the refrigerant circulation system in normal heating mode. Under heating conditions, high-temperature and high-pressure refrigerant is discharged from the exhaust end 211 of the compressor 210, enters the condenser 220 to liquefy and release heat, which is used to heat indoor air or circulating water, etc. Then, the liquid refrigerant is throttled and depressurized through the first throttling device 230, and then enters each of the main flow channels 110 in the main evaporator 100 to absorb ambient heat and evaporate, finally returning to the suction end 212 of the compressor 210 in the form of low-temperature and low-pressure gas, completing one heating cycle.

[0054] The first throttle valve 230 can be a fixed orifice plate or a capillary tube to achieve the refrigerant throttling function and has a simple structure. Alternatively, depending on system requirements, the first throttle valve 230 can be an electronic throttle valve. Correspondingly, the compressor 210 can also be a variable frequency compressor.

[0055] Combination Figure 2 and Figure 3 The defrost circuit 300 includes the exhaust end 211 of the compressor 210, a first electrically controlled valve 310, at least two defrost channels 120, a second expansion valve 320, a defrost evaporator 330, and the suction end 212 of the compressor 210, all connected in a loop. The defrost circuit 300 is an auxiliary circulation path activated by the refrigerant circulation system when defrosting is required. During defrosting, high-temperature, high-pressure refrigerant is drawn from the exhaust end 211 of the compressor 210 and diverted, entering the defrost channel 120 in the main evaporator 100 through the first electrically controlled valve 310 to heat the frosted area. After defrosting, the refrigerant is depressurized by the second expansion valve 320 and undergoes auxiliary heat exchange and vaporization through the defrost evaporator 330, finally returning to the suction end 212 of the compressor 210.

[0056] The first electrically controlled valve 310 can be connected to the control module, allowing the control module to select whether to start or stop the first electrically controlled valve 310 as needed, thereby opening or closing the defrosting circuit. The defrosting evaporator 330 can be a finned heat exchanger, a plate heat exchanger, or a shell-and-tube heat exchanger, used to absorb heat and vaporize the liquid refrigerant after defrosting, preventing excessive accumulation of liquid refrigerant or preventing liquid refrigerant from being drawn into the compressor 210 and causing structural damage.

[0057] Thus, through the configuration of the main circuit 200, the defrost circuit 300, and the aforementioned main evaporator 100, the main flow channel 110 in the main evaporator 100 remains open during defrost operation to ensure normal heat absorption and vaporization of the internal refrigerant, preventing shutdown during heating. Furthermore, the main evaporator 100 is configured such that at least one defrost flow channel 120 in the heat exchange zone 130 is connected between the exhaust end 211 of the compressor 210 and the second throttle valve 320. Specifically, the defrost circuit 300 is activated via the first electronically controlled valve to allow a portion of the refrigerant to flow directly from the compressor 210 to the defrost flow channel 120, causing the refrigerant to liquefy and release heat within the defrost flow channel 120. This heats the main flow channel 110 in the heat exchange zone 130 where the defrost flow channel 120 is located, enabling the main flow channel 110 to quickly defrost.

[0058] During the defrosting process via the defrosting channel 120, the high-temperature, high-pressure gaseous refrigerant bypassing the compressor 210 exhaust end 211 to the main evaporator 100 only needs to flow through the defrosting channel 120 in one of the heat exchange zones 130 to liquefy and release heat. This concentrates the limited refrigerant heat to generate a higher heating temperature in a unit heat exchange zone 130, rapidly heating and melting the frost on the outer wall of the main flow channel 110 in that heat exchange zone 130, thereby improving the defrosting speed and effect. Subsequently, the defrosting channels 120 in other heat exchange zones 130 are sequentially switched to connect between the compressor 210 and the second throttle valve 320, sequentially performing rapid defrosting on the main flow channels 110 in the other heat exchange zones 130.

[0059] During the aforementioned defrosting process, the first heat exchange zone 130 achieves rapid defrosting of the main flow channel 110 through concentrated heat. This allows for the rapid restoration of some heating capacity of the main circuit 200 without shutting down the main circuit 200, while maintaining a high energy efficiency ratio. Simultaneously, the presence of defrosting channels 120 corresponding to the main flow channel 110 in each heat exchange zone 130 not only increases the defrosting coverage of the main evaporator 100 but also improves the uniformity of coverage in the defrosting channels 120. This reduces the proportion of localized ice blockage and air blockage, improving the overall defrosting speed and effect of the refrigerant circulation system. Furthermore, it effectively enhances the operational reliability, user comfort, and system energy efficiency ratio of the refrigerant circulation system under low-temperature and high-humidity conditions.

[0060] It should be noted that, in the defrosting operation using a single heat exchange zone 130 for heating and defrosting, if the compressor 210 experiences overheating at the discharge end 211, the main circuit 200 cannot quickly resolve the refrigerant discharge overheating issue because the main evaporator 100 is in a frosted state. In this case, the defrosting channels 120 of other heat exchange zones 130 can be opened to allow more refrigerant at the discharge end 211 to flow through the defrosting channels 120 in the defrosting circuit 300. This allows the refrigerant to fully liquefy at the main evaporator 100 and release heat to heat the frost adhering to the outer wall of the main flow channel 110, achieving both efficient defrosting and rapid relief of the compressor 210 discharge overheating problem.

[0061] For example, such as Figure 1 As shown, the main evaporator 100 includes a control valve group 150, which includes at least two second electrically controlled valves 156. One of the second electrically controlled valves 156 is connected to a defrost channel 120 and is used to control the opening and closing states of the defrost channel 120.

[0062] The second electrically controlled valve 156 can be installed at the inlet or outlet end of the defrost channel 120. Through the action of its internal valve core or valve disc, it can block or allow refrigerant to flow through the second electrically controlled valve 156 and the defrost channel 120. For example, when defrosting is required on the main flow channel 110 in a heat exchange zone 130, the corresponding second electrically controlled valve 156 is opened, allowing high-temperature, high-pressure refrigerant to enter the corresponding defrost channel 120 of that heat exchange zone 130 to heat the main flow channel 110 for defrosting. When defrosting is complete or no longer required, the corresponding second electrically controlled valve 156 is closed, preventing refrigerant from entering. This design is simple and effective.

[0063] It should be noted that the electrically controlled valve and electronic expansion valve in this application can be either electromagnetically driven or motor-driven, as long as they can be accurately controlled through the control terminal, and there are no restrictions on this.

[0064] Or, such as Figure 4 As shown, the control valve assembly 150 includes a valve body 151 and a valve core 152. The valve body 151 has a valve cavity 153 and a liquid inlet 154 and at least two liquid outlets 155 connected thereto. One liquid outlet 155 is connected to a defrosting channel 120, and the liquid inlet 154 is connected to a first solenoid valve 310. The valve core 152 is rotatably or slidably disposed in the valve cavity 153, and the valve core 152 is configured to connect the liquid inlet 154 and one of the liquid outlets 155.

[0065] For example, if there are two heat exchange zones 130 and defrost channels 120, the control valve assembly 150 can be a two-position three-way valve. If there are three heat exchange zones 130 and defrost channels 120, the control valve assembly 150 can be a three-position four-way valve. If there are four heat exchange zones 130 and defrost channels 120, the control valve assembly 150 can be a four-position five-way valve, and so on.

[0066] For example, a rotary valve core 152 can be a cylinder or sphere with a specific opening. By rotating, the opening is aligned with different liquid outlets 155, thereby opening the corresponding defrosting flow path 120. A sliding valve core 152 can be a plunger with a groove or hole. By sliding axially, the groove or hole is aligned with different liquid outlets 155, thereby opening the corresponding defrosting flow path 120. By using an integrated control valve assembly 150, the number of parts can be reduced to simplify system complexity and improve overall maintainability.

[0067] By introducing control valve assembly 150 into the main evaporator 100 and configuring each control valve assembly 150 to correspond one-to-one with the defrost channel 120, precise and independent control of each defrost channel 120 in the main evaporator 100 can be achieved. During defrosting, the defrost channel 120 in the corresponding heat exchange zone 130 can be selectively opened or closed according to the frosting conditions of different heat exchange zones 130, precisely guiding the high-temperature, high-pressure refrigerant to the area requiring defrosting. This avoids insufficient heat caused by overall defrosting, thus significantly improving defrosting efficiency and shortening defrosting time. Simultaneously, precise control of the defrost channel 120 effectively prevents system performance degradation due to over-defrosting or uneven defrosting, ensuring the stability and efficiency of the refrigerant circulation system under heating conditions.

[0068] In some other embodiments, at least two first solenoid valves 310 may be provided, with each of the at least two first solenoid valves 310 corresponding to at least two defrosting channels 120. That is, there is no need to provide an additional corresponding control valve group 150, and individual control of each defrosting channel 120 can still be achieved, further simplifying the system structure.

[0069] In the above scheme, the defrosting circuit 300 is equipped with a throttling device, namely the second throttling device 320, between the defrosting flow channel 120 and the defrosting evaporator 330.

[0070] Or, such as Figure 2 and Figure 3 As shown, the defrosting circuit 300 includes a third throttling device 340, which is connected in series with the second throttling device 320 on the side away from the defrosting evaporator 330. The second throttling device 320 is an electronic expansion valve. An electronic expansion valve is a throttling device that can precisely adjust the refrigerant flow rate according to a control signal. Compared to traditional fixed orifice plates or capillary tubes, electronic expansion valves can adjust their opening degree in real time according to system operating parameters (such as superheat, subcooling, and pressure) to optimize system performance and improve energy efficiency ratio.

[0071] The third throttling device 340 can be a throttling element with a fixed throttling area, such as a throttling orifice plate or capillary tube. The third throttling device 340 is connected in series upstream of the second throttling device 320, and can play a role in auxiliary throttling and stabilizing the flow rate. This can avoid engineering problems such as valve core erosion, high noise, and severe pressure fluctuations caused by excessive pressure drop at the electronic expansion valve during single-stage throttling.

[0072] Thus, the electronic expansion valve introduced into the defrost circuit 300, acting as the second throttle 320, can precisely and dynamically adjust the refrigerant flow rate according to actual operating conditions, thereby optimizing the defrosting effect and improving defrosting efficiency. Simultaneously, the third throttle 340, arranged in series, provides a stable base throttling effect, working in conjunction with the electronic expansion valve to further enhance the stability and reliability of flow control, avoiding flow fluctuations or inaccurate control problems that might occur with a single throttling element.

[0073] Correspondingly, such as Figure 3 As shown, the defrost circuit 300 includes a first one-way valve 350, which is connected in series between the defrost flow channel 120 and the defrost evaporator 330 to prevent refrigerant backflow under non-defrost conditions or during system switching. For example, when the defrost circuit 300 stops operating, the one-way valve can prevent high-pressure or low-pressure refrigerant in the main circuit 200 from flowing back into the defrost circuit 300, thereby protecting the components of the defrost circuit 300 and ensuring that the refrigerant flows along a preset path, maintaining the stability and reliability of the system operation.

[0074] The defrosting evaporator 330 can be a finned heat exchanger to rapidly defrost frost adhering to the main evaporator 100 by absorbing heat from the environment.

[0075] However, in order to further improve defrosting efficiency, such as Figure 7 As shown, the defrosting evaporator 330 includes a first heat exchange channel 331 and a second heat exchange channel 332 that exchange heat with each other. That is, the defrosting evaporator 330 can be a plate heat exchanger or a shell-and-tube heat exchanger. In the defrosting circuit 300, the first heat exchange channel 331 is connected in series between the suction end 212 of the compressor 210 and the second throttle 320.

[0076] Reference Figure 3 and Figure 5 The refrigerant circulation system also includes a first heating branch 400, which includes a second one-way valve 420, a second heat exchange channel 332, and a third electrically controlled valve 410 arranged in series. In the main circuit 200 during heating operation, at least a portion of the main circuit 200 between the discharge end 211 of the compressor 210 and the first throttle 230 is arranged in parallel with the first heating branch 400. The second one-way valve 420 and the third electrically controlled valve 410 can be located on one side of the second heat exchange channel 332, or they can be located on opposite sides of the second heat exchange channel 332.

[0077] The first heating branch 400 can be connected in parallel with the condenser 220, or the first heating branch 400 can be connected in parallel with a portion of the main circuit 200 upstream of the condenser 220, or the first heating branch 400 can be connected in parallel with a portion of the main circuit 200 downstream of the condenser 220.

[0078] By setting the first heating branch 400 in parallel with part of the main circuit 200, the high-temperature and high-pressure refrigerant discharged from the exhaust end 211 of the compressor 210 can be diverted to the first heating branch 400 and flow through the second heat exchange channel 332 to heat the liquid refrigerant in the first heat exchange channel 331 (i.e., defrosting circuit 300).

[0079] In this way, the high-temperature refrigerant in the main circuit 200 can be effectively used to heat the defrosting evaporator 330 in the defrosting circuit 300, so that the main flow channel 110 in the corresponding heat exchange zone 130 can be quickly heated through the defrosting flow channel 120 at the main evaporator 100, thereby achieving the purpose of rapid defrosting. Furthermore, by using the refrigerant at the condenser 220 to heat the refrigerant in the first heat exchange channel 331 and make it fully vaporized, it is possible to avoid liquid slugging damage caused by the compressor 210 sucking in liquid refrigerant, and also to avoid the accumulation of liquid refrigerant, thereby improving the utilization efficiency of the refrigerant circulation.

[0080] Furthermore, since the defrosting circuit 300 only relies on the refrigerant circulation within the system to achieve the heating and defrosting effect during defrosting, it can significantly reduce the energy consumption of the system during heating or defrosting, thereby improving overall energy efficiency.

[0081] It should be noted that in the first heating branch 400, the third electrically controlled valve 410 is used to control the opening or closing of the first heating branch 400. The second one-way valve 420 is used to prevent the backflow of refrigerant in the first heating branch 400 from affecting the overall heat exchange effect.

[0082] Furthermore, such as Figure 7 As shown, the defrosting evaporator 330 includes a first heat exchange channel 331 and a third heat exchange channel 333 that exchange heat with each other. In the defrosting circuit 300, the first heat exchange channel 331 is connected in series between the suction end 212 of the compressor 210 and the second throttle valve 320. Figure 3 and Figure 5 The refrigerant circulation system also includes a second heating branch 500, which includes a third one-way valve 520, a third heat exchange channel 333, and a fourth electrically controlled valve 510 arranged in series. In the defrost circuit 300, at least a portion of the defrost circuit 300 between the discharge end 211 of the compressor 210 and the defrost channel 120 is arranged in parallel with the second heating branch 500.

[0083] The third check valve 520 and the fourth electrically controlled valve 510 can be located on one side of the third heat exchange channel 333, or they can be located on opposite sides of the third heat exchange channel 333.

[0084] By setting the second heating branch 500 in parallel with part of the defrosting circuit 300, the high-temperature and high-pressure refrigerant discharged from the exhaust end 211 of the compressor 210 can be diverted to the second heating branch 500 and flow through the third heat exchange channel 333 to heat the liquid refrigerant in the first heat exchange channel 331, thereby improving the overall utilization efficiency of the refrigerant circulation under defrosting conditions.

[0085] By configuring the first heating branch 400 and the second heating branch 500, the high-temperature refrigerant discharged from the compressor 210 can be effectively used to preheat the refrigerant on the suction side of the defrost circuit 300, thereby increasing the superheat of the refrigerant entering the compressor 210 and improving the operating efficiency and reliability of the compressor 210. Furthermore, the solution also enables energy recovery within the system, reducing energy consumption during defrosting and improving overall energy efficiency.

[0086] It should be noted that the first heating branch 400 and the second heating branch 500 can be optionally configured in the refrigerant circulation system. In this case, the defrosting evaporator 330 is a plate heat exchanger or a shell-and-tube heat exchanger.

[0087] Alternatively, the first heating branch 400 and the second heating branch 500 can also be configured simultaneously in the refrigerant circulation system. In this case, the defrosting evaporator 330 is a shell-and-tube heat exchanger, the first heat exchange channel 331 is the internal space of the shell, and the second heat exchange channel 332 and the third heat exchange channel 333 are heat exchange coils installed in the internal space, so that the first heat exchange channel 331 can be heated by the second heat exchange channel 332 and the third heat exchange channel 333 to improve the superheat of the refrigerant.

[0088] In addition, with the setting of the second heating branch 500, the refrigerant after defrosting returns directly to the suction port of the compressor 210 through the first heat exchange channel 331, without having to flow through the condenser 220, thus completely avoiding the problem of the low-temperature refrigerant absorbing heat from the water after defrosting, which would cause the water temperature in the tank to drop.

[0089] For example, such as Figure 1 As shown, the main evaporator 100 includes a plurality of fins 140, at least two main flow channels 110, and at least two defrosting flow channels 120. The plurality of fins 140 are spaced apart along a second direction, which can be a straight line or a curved direction. The main flow channels 110 and defrosting flow channels 120 are heat exchange tubes and are inserted through the plurality of fins 140 along the second direction to increase the heat exchange contact area between the main flow channels 110 and the defrosting flow channels 120.

[0090] Taking a main evaporator 100 with four sequentially distributed heat exchange zones 130 along a first direction as an example, this first direction can be parallel to the second direction or have an angle, such as the first direction being perpendicular to the second direction. Each heat exchange zone 130 has a main flow channel 110 and a defrost flow channel 120. The main flow channel 110 is used by the refrigerant circulation system to absorb heat during heating to heat indoor air or domestic water, etc. The defrost flow channel 120 rapidly heats the main flow channel 110 to complete defrosting during defrosting, at least through thermal radiation and heat transfer from the fins 140.

[0091] like Figure 5 and Figure 6 As shown, the main circuit 200 includes a cooling fan 250, which drives airflow through the main evaporator 100. Along the airflow direction, the main flow channel 110 in the same heat exchange zone 130 is located downstream of the defrosting channel 120. This allows the cooling fan 250 to drive the heated air, heated by the defrosting channel 120, through the main flow channel 110, further improving the defrosting speed and effectiveness of the main flow channel 110.

[0092] For example, such as Figure 1 As shown, along the first direction (e.g., up and down), the main flow channel 110 and the defrosting flow channel 120 are alternately distributed in the same heat exchange zone 130. This alternating piping design ensures that the heat from the defrosting flow channel 120 is evenly distributed to the main flow channel 110 throughout the entire heat exchange zone 130, avoiding localized overheating or incomplete defrosting. This ensures that the frost layer throughout the entire heat exchange zone 130 is heated and melted, thereby improving the overall defrosting effect and uniformity.

[0093] In the same heat exchange zone 130, the distance between the main flow channel 110 and the defrosting flow channel 120 is less than or equal to 10 mm. For example, the distance between the main flow channel 110 and the defrosting flow channel 120 is 5-10 mm, and the distance between adjacent main flow channels 110 and defrosting flow channels 120 is 5-10 mm.

[0094] For example, a mechanical tube expansion process can be used to ensure that the tube walls of the main flow channel 110 and the defrosting flow channel 120 are tightly fitted to the fins 140. The fins 140 remain continuous without any cutting, slotting, or insulation material, forming a complete metal heat conduction path. In the first direction (i.e., the height direction), each heat exchange zone 130 is a fin area of ​​1 / N height (N is the number of heat exchange zones 130), and each heat exchange zone 130 contains 3 to 5 straight copper tubes in the main flow channel 110 and the defrosting flow channel 120.

[0095] For example, the condenser 220 can be configured as an indoor heat exchanger, such as a finned heat exchanger. The main evaporator 100 is an outdoor heat exchanger to meet the cooling, heating, and dehumidification requirements of the air conditioner.

[0096] Alternatively, the condenser 220 can be a plate heat exchanger, a shell-and-tube heat exchanger, or a coil heat exchanger. Among these, the condenser 220 of the plate heat exchanger, shell-and-tube heat exchanger, and coil heat exchanger can be used in heat pump units, as well as in air conditioning chilled or hot water units, without limitation.

[0097] In this embodiment, the main circuit 200 can be a heat pump unit without the need for additional configuration of a condition switching structure.

[0098] Or, such as Figure 2 and Figure 6 As shown, the main circuit 200 includes a four-way valve 240. The first and second ends of the four-way valve 240 are connected to the discharge end 211 and suction end 212 of the compressor 210, respectively. The third end of the four-way valve 240, the condenser 220, the first throttle 230, multiple main flow channels 110, and the fourth end of the four-way valve 240 are connected in sequence. The four-way valve 240 allows the main circuit 200 to flexibly switch between heating, cooling, and dehumidification modes.

[0099] In some embodiments, such as Figure 2 and Figure 3 As shown, the main evaporator 100 includes a first gas collecting pipe 160 and a second gas collecting pipe 170. The first gas collecting pipe 160 has a first port and multiple second ports. The first port is connected to the fourth end of a four-way valve 240, and the multiple second ports are connected to multiple main flow channels 110. The second gas collecting pipe 170 has a third port and multiple fourth ports. The third port is connected to a second throttle valve 320, and the multiple fourth ports are connected to multiple defrosting channels 120.

[0100] The first and second gas collection pipes 160 and 170 serve as refrigerant collection devices, respectively used for the main flow channel 110 and the defrosting flow channel 120. This design ensures uniform distribution of refrigerant in the parallel flow channels, avoiding problems such as decreased heat exchange efficiency or incomplete defrosting caused by uneven flow.

[0101] To ensure stable refrigerant circulation in the main circuit 200 and defrost circuit 300, such as Figure 6 As shown, the main circuit 200 includes a first gas-liquid separator 260, which is connected in series to the suction end 212 of the compressor 210. When the main circuit 200 is equipped with a four-way valve 240, the first gas-liquid separator 260 is connected in series between the suction end 212 and the fourth end of the four-way valve 240. This is to prevent insufficiently vaporized liquid refrigerant from being drawn into the compressor 210, causing liquid slugging damage.

[0102] At this point, the defrosting evaporator 330 can be connected to the suction end 212 of the compressor 210 via the first gas-liquid separator 260. That is, the defrosting circuit 300 and the main circuit 200 share a gas-liquid separation structure to simplify the complexity of the entire system.

[0103] Or, such as Figure 2 As shown, the defrosting circuit 300 includes a second gas-liquid separator 360, which is connected in series between the suction end 212 of the compressor 210 and the defrosting evaporator 330. This ensures that the defrosting circuit 300 and the main circuit 200 each have independent gas-liquid separation structures, thereby improving the operational stability of the defrosting circuit 300 and the main circuit 200.

[0104] To achieve automated operation and control of the refrigerant circulation system, such as Figure 8 As shown, the refrigerant circulation system includes a control module 610, which is connected to a compressor 210, a first throttle valve 230, a first electrically controlled valve 310, and a second throttle valve 320. The first throttle valve 230 and the second throttle valve 320, via the electronic expansion valve, control the refrigerant circulation channels in the main circuit 200 and the defrost circuit 300. The defrost circuit 300 can be started or stopped by the opening and closing state of the first electrically controlled valve 310.

[0105] In addition, continue to refer to Figure 8 The control module 610 is also electrically connected to the control valve group 150 (such as multiple second solenoid valves 156), the third solenoid valve 410, the fourth solenoid valve 510, and the four-way valve 240. At this time, by switching the state of the control valve group 150 or switching the state of the multiple second solenoid valves 156, the corresponding defrosting flow channel 120 can be selectively activated after the defrosting circuit 300 is started, so as to sequentially heat the main flow channel 110 in the heat exchange zone 130 where frost is severe.

[0106] Based on this, the third solenoid valve 410 and the fourth solenoid valve 510 can be selectively controlled to activate the corresponding first heating branch 400 or second heating branch 500 to achieve efficient defrosting heating.

[0107] To achieve automated control and switching of the refrigerant circulation system, such as Figure 8 As shown, the control module 610 is also electrically connected to a first temperature sensor 620, multiple second temperature sensors 630, and a third temperature sensor 640. (Refer to...) Figure 1 and Figure 2A first temperature sensor 620 is located at the exhaust end 211 of the compressor 210 to detect the exhaust temperature. Multiple second temperature sensors 630 are located in multiple heat exchange zones 130 to detect the heat exchange temperature of each heat exchange zone 130. A third temperature sensor 640 is used to detect the ambient temperature. This allows the control module 610 to acquire the exhaust temperature, multiple heat exchange temperatures, and ambient temperature in real time, and to automatically control the operation of the refrigerant circulation system based on this information.

[0108] For example, multiple second temperature sensors 630 are configured to be respectively disposed in multiple heat exchange zones 130 in the main evaporator 100 for detecting the heat exchange temperature of each heat exchange zone 130. These sensors can be of thermistor, thermocouple, or similar types. By arranging independent temperature sensors in different heat exchange zones 130, accurate detection of frost formation in each heat exchange zone 130 can be achieved, thereby providing accurate temperature data support for subsequent regional defrosting.

[0109] For example, in the defrosting circuit 300, the refrigerant flows sequentially through the third throttle valve 340 and the second throttle valve 320. The third throttle valve 340 of the fixed orifice plate has an orifice diameter of φ3.0mm and serves as the first-stage throttling element, reducing the pressure of the high-pressure refrigerant (1.0~2.5MPa) flowing out of the defrosting channel 120 to an intermediate pressure (1.0~1.5MPa), at which point the corresponding refrigerant temperature is 40~65℃. The second throttle valve 320 of the electronic expansion valve serves as the second-stage throttling element, further reducing the pressure of the refrigerant from the intermediate pressure to the suction pressure (0.5~0.8Pa), and the return gas flow rate is controlled by adjusting the opening of the second throttle valve 320 to regulate the exhaust temperature.

[0110] Secondly, embodiments of this application provide a defrosting control method for a refrigerant circulation system, used to control the refrigerant circulation system in the first aspect, such as... Figure 9 As shown, the defrosting control method includes the following steps: Step S100: Control the refrigerant circulation system to start the main circuit 200 and switch to heating mode.

[0111] Step S200: Obtain the heat exchange temperature of the heat exchange zone 130 in the main evaporator 100.

[0112] Step S300: If the heat exchange temperature of at least a portion of the heat exchange zone 130 is lower than the first threshold K1 and the duration exceeds the first duration T1, mark that portion of the heat exchange zone 130 as the target area. Step S400: Control the start of the defrosting circuit 300 to sequentially heat the heat exchange zone 130 of the target area.

[0113] For example, the system can be started and maintained in heating mode in the main circuit 200 by the control module 610. At this time, the high-temperature and high-pressure refrigerant discharged from the exhaust end 211 of the compressor 210 liquefies in the condenser 220 and releases heat to fully heat the preset area. Subsequently, the liquefied refrigerant absorbs heat and vaporizes in the multiple main channels 110 of the main evaporator 100 after flowing through the first throttling device 230, so as to realize the cyclical change of the refrigerant state. At the main evaporator 100, if the ambient temperature is low and the humidity is high, frost is easily condensed on the fins 140 and the main channels 110, which will reduce the air flow and the heat exchange area with the air at the main evaporator 100, resulting in a lower overall heating efficiency of the system.

[0114] Based on this, the control module 610 collects the heat exchange temperature of each heat exchange zone 130 in real time at a cycle of five to ten seconds. When the temperature of any heat exchange zone 130 is detected to be lower than the first threshold K1 (e.g., -4 to 2℃), if the low temperature duration of the heat exchange zone 130 exceeds the first duration (e.g., 40 to 60 seconds), the heat exchange zone 130 is identified as a target area with severe frost.

[0115] Subsequently, the control module 610 opens the first electronically controlled valve 310 to activate the defrosting circuit 300, and through the control valve group 150, opens the defrosting channel 120 in the heat exchange zone 130 where the target area is located, so that the high-temperature refrigerant discharged by the compressor 210 flows directly into the defrosting channel 120 of the target area through the first electronically controlled valve 310, so as to quickly heat and melt the frost attached to the outer wall of the main channel 110 in the heat exchange zone 130.

[0116] If there are two or more heat exchange zones 130 corresponding to the target area, the defrosting can be performed on each heat exchange zone 130 in sequence, starting with the one with the lowest heat exchange temperature. That is, after the defrosting of the previous heat exchange zone 130 is completed, the system automatically switches to the heat exchange zone 130 of the next target area and performs the defrosting operation in sequence.

[0117] Since the defrosting control method for the refrigerant circulation system provided in this application embodiment is used to control the refrigerant circulation system in the first aspect, the defrosting control method has all the effects of the above-mentioned embodiments involving the refrigerant circulation system, and will not be repeated here.

[0118] The heating sequence of the heat exchange zone 130 corresponding to the target area is arranged in order of increasing heat exchange temperature. Since a lower heat exchange temperature usually means more severe frost formation in the heat exchange zone 130, it is prioritized for heating treatment. This ensures that the main channel 110 in the heat exchange zone 130 with the most severe frost formation can be heated and defrosted in a timely and effective manner, thereby avoiding a decrease in overall heat exchange efficiency due to severe local frost formation.

[0119] Step S400 includes: The first electrically controlled valve 310 is opened, and the defrosting channels 120 corresponding to each heat exchange zone 130 in the target area are sequentially opened.

[0120] The first electrically controlled valve 310 can control the opening of the defrost circuit 300 so that the high-temperature and high-pressure refrigerant discharged from the compressor 210 can enter the defrost circuit 300. In the defrost operation, when it is necessary to start the defrost circuit 300, the control module 610 will issue a command to open the first electrically controlled valve 310 so that the high-temperature refrigerant can enter the subsequent defrost flow channel 120.

[0121] After the first solenoid valve 310 is opened, the control module 610 will, based on the heating sequence of one or more heat exchange zones 130 in the preset target area, sequentially or automatically connect the defrosting channels 120 of the corresponding heat exchange zones 130.

[0122] If each second electrically controlled valve 156 is connected to a defrosting channel 120, the control module 610 can sequentially open the second electrically controlled valves 156 in the target area, or the corresponding heat exchange zone 130. Alternatively, if the control valve assembly 150 includes a valve body 151 and a valve core 152, and the valve core 152 is configured to open the inlet port 154 and one of the outlet ports 155, then different defrosting channels 120 can be sequentially selected by controlling the rotation or sliding of the valve core 152. This ensures that the high-temperature refrigerant can flow centrally to the specific area that needs defrosting.

[0123] Thus, during defrosting control of the refrigerant circulation system, the defrosting priority can be intelligently determined based on the actual frost conditions (i.e., heat exchange temperatures) of each heat exchange zone 130 in the main evaporator 100. The area with the lowest heat exchange temperature is prioritized for heating, ensuring that the heat exchange zone 130 with the most severe frost can be treated promptly and effectively, thereby avoiding a decrease in overall heat exchange efficiency due to severe localized frost.

[0124] Simultaneously, by opening the first electrically controlled valve 310 and controlling the sequential opening of the defrosting channels 120 corresponding to the target areas, the high-temperature and high-pressure heating refrigerant can be centrally delivered to the specific channel that needs defrosting. This centralized heating method avoids the temperature drop caused by the refrigerant flowing dispersedly in multiple channels, ensuring that the refrigerant entering the defrosting channel 120 has a high temperature and enthalpy, thereby significantly improving defrosting efficiency and speed. Furthermore, sequentially opening the defrosting channels 120 also helps maintain the stable operation of the compressor 210, avoiding system pressure fluctuations caused by the instantaneous opening of all channels, thus improving the operational stability and energy efficiency of the entire refrigerant circulation system.

[0125] The second throttle 320 is an electronic expansion valve and is electrically connected to the control module 610. Based on this, step S400 includes: Step S421: Obtain the exhaust temperature of compressor 210 and compare the exhaust temperature, the second threshold K2 and the third threshold K3. The second threshold K2 is greater than the third threshold K3.

[0126] Step S422: If the exhaust temperature is greater than the second threshold K2, control the opening of the second throttle 320 to increase the first preset value A1.

[0127] Step S423: If the exhaust temperature is less than the third threshold K3, control the opening of the second throttle 320 to decrease the second preset value A2.

[0128] Step S424: If the exhaust temperature is between the third threshold K3 and the second threshold K2, when the exhaust temperature is greater than the target temperature T0, the opening of the second throttle 320 is increased by the third preset value A3; when the exhaust temperature is less than the target temperature T0, the opening of the second throttle 320 is decreased by the third preset value A3.

[0129] It should be noted that the second threshold K2 and the third threshold K3 are the upper and lower limits of the compressed exhaust temperature, respectively. The second threshold K2 can range from 110 to 120℃, and the third threshold K3 can range from 85 to 95℃. The target temperature T0 is the optimal exhaust temperature range for the compressor 210 under current operating conditions; for example, the target temperature T0 can range from 100 to 105℃. The first preset value A1, the second preset value A2, and the third preset value A3 are the opening adjustment ranges of the electronic expansion valve, decreasing sequentially; for example, the first preset value A1 is 8%, the second preset value A2 is 5%, and the third preset value A3 is 3%.

[0130] Through the above technical solution, this application provides a defrosting control strategy that dynamically adjusts the opening of the second throttle valve 320 (electronic expansion valve) based on exhaust temperature. Specifically, by monitoring the exhaust temperature of the compressor 210 in real time and comparing it with a preset threshold and a target temperature T0, the opening of the electronic expansion valve is intelligently adjusted.

[0131] When the exhaust temperature is too high, the opening of the electronic expansion valve is increased to increase the refrigerant flow, which effectively reduces the exhaust temperature of the compressor 210, thereby preventing the compressor 210 from overheating, improving the stability of the system and extending the service life of the compressor 210.

[0132] When the exhaust temperature is too low, the opening of the electronic expansion valve is reduced to decrease the refrigerant flow, thereby increasing the exhaust temperature and ensuring that the defrosting circuit 300 can provide sufficient heat to improve defrosting efficiency and shorten defrosting time.

[0133] When the exhaust temperature is within the normal operating range, precise comparison and fine-tuning with the target temperature T0 enable the system to operate stably at the optimal balance point between defrosting efficiency and energy consumption, further optimizing the overall performance and economy of the system. This dynamic and precise control method effectively solves the problems of insufficient compressor 210 protection, low defrosting efficiency, or unstable system operation caused by improper control of the second throttle opening 320 during the defrosting process, significantly improving the reliability and energy efficiency of the refrigerant circulation system.

[0134] In some embodiments, before step S421, step S400 further includes: Step S410: Obtain the ambient temperature and control the second throttle 320 to switch to the corresponding initial opening based on the ambient temperature.

[0135] The ambient temperature refers to the ambient temperature of the space where the main evaporator 100 is located. For example, the third temperature sensor 640 is set on the air inlet side of the main evaporator 100 to detect the air inlet temperature as the ambient temperature.

[0136] If the ambient temperature is less than -15℃, the initial opening of the second throttle 320 is set to 75%-85%. If the ambient temperature is in the range of -15℃ to -5℃, the initial opening of the second throttle 320 is 60%-70%. If the ambient temperature is in the range of -5℃ to 5℃, the initial opening of the second throttle 320 is 45%-55%. If the ambient temperature is greater than 5℃, the initial opening of the second throttle 320 is 30%-40%.

[0137] At the start of the defrost circuit 300, the system can intelligently set a suitable initial opening for the second expansion valve 320 based on the current ambient temperature. This avoids refrigerant flow and pressure imbalances caused by improper opening of the second expansion valve 320 during the initial defrosting phase, thereby reducing the adjustment time required for the system to reach optimal defrosting conditions. Especially when ambient temperature fluctuates significantly, the preset mechanism allows the defrosting process to enter the high-efficiency operating range more quickly, significantly improving the defrosting start-up response speed and overall efficiency. This ensures that the main evaporator 100 can complete defrosting promptly and thoroughly, thus guaranteeing the stability and energy efficiency of the refrigerant circulation system under heating conditions.

[0138] In some implementations, step S400 further includes: If the exhaust temperature is greater than the fourth threshold K4, and the fourth threshold K4 is greater than the second threshold K2, the opening of the second throttle 320 is switched to 100%, and the operating frequency of the compressor 210 is reduced.

[0139] The fourth threshold K4 ranges from 120-130℃. When the discharge temperature of compressor 210 exceeds the fourth threshold K4, it may be in a dangerous state of overheating or high-pressure operation. To protect compressor 210, control module 610 will immediately take emergency measures: First, it will switch the opening of the second throttle 320 to 100%, i.e., fully open. This operation aims to maximize the refrigerant flow through defrosting circuit 300, thereby increasing the suction superheat of compressor 210, reducing discharge temperature, and alleviating the heat load on compressor 210. Second, control module 610 will reduce the operating frequency of compressor 210. Reducing the operating frequency can reduce the work done and heat generated by compressor 210, further reducing discharge temperature and system pressure, thereby effectively preventing compressor 210 from being damaged due to overheating or overload, and ensuring long-term stable operation of the system.

[0140] It should be noted that after defrosting is completed in each heat exchange zone 130 corresponding to the target area, the target area needs to be reconfirmed and reordered before switching to the next heat exchange zone 130. That is, the control module 610 will dynamically adjust based on the actual frosting status of each heat exchange zone 130 in the main evaporator 100. For example, the control module 610 will again acquire the heat exchange temperature of all heat exchange zones 130, identify areas where frosting still exists (i.e., temperatures below the first threshold K1 and exceeding the first duration T1) as new target areas, and reorder these target areas according to the severity of frosting (e.g., heat exchange temperature from low to high). This dynamic adjustment mechanism ensures that defrosting resources are always preferentially allocated to the areas most in need of defrosting, improving defrosting efficiency and response speed.

[0141] In order to precisely control the defrosting termination of a single heat exchange zone 130, this application sets two conditions: The first method involves stopping heating the heat exchange zone 130 if its heating temperature is greater than or equal to the fifth threshold K5 and maintained for a third duration T3. The fifth threshold K5 is greater than 0°C, such as 3-5°C. The third duration T is 10-20 seconds to avoid misjudgments caused by instantaneous temperature fluctuations and to ensure thorough defrosting.

[0142] The second method involves stopping heating the heat exchange zone 130 when the heating time reaches the fourth duration T4 (e.g., more than 100 seconds). This serves as a protection mechanism to prevent a region from failing to reach the required temperature for an extended period under extreme conditions such as frost formation or sensor malfunction, thus avoiding energy waste or system abnormalities.

[0143] Once the target area has defrosted completely, and no new target area appears within the second time period T2 (e.g., 30-60 seconds), the defrosting circuit 300 is shut down. That is, after all heat exchange zones 130 in the target area have defrosted, the system does not immediately shut down the defrosting circuit 300. Instead, it enters a short monitoring period, which can be the last period of time during the defrosting process of the last heat exchange zone 130. Alternatively, all defrosting channels 120 can be opened simultaneously, or the second throttle 320 can be adjusted to its minimum opening to maintain the circulation of the defrosting circuit 300. If no new heat exchange zone 130 is identified as a target area within 60 seconds, meaning the main evaporator 100 has been completely defrosted and there are no new signs of frost, the control module 610 will then shut down the defrosting circuit 300. The setting of the second time period T2 provides a buffer period to ensure that no hidden or newly formed frost layer is missed after all visible frost has melted, avoiding frequent activation of the defrosting circuit 300.

[0144] In some embodiments, the defrosting sequence of the heat exchange zone 130 in the target area can also be set by other conditions, i.e., the defrosting control method includes: Obtain the time interval between two adjacent heating conditions in heat exchange zone 130.

[0145] The frosting rate is calculated based on multiple time intervals for each heat exchange zone 130, and the frosting rates of multiple heat exchange zones 130 are compared.

[0146] If the frosting rate of heat exchange zone 130 exceeds the preset value, the heating priority or heating time of heat exchange zone 130 will be increased.

[0147] The control module 610 calculates the frosting rate of each heat exchange zone 130 based on multiple time intervals acquired. The frosting rate is a key indicator of how quickly frosting occurs, and it is generally negatively correlated with the time interval; that is, the shorter the time interval, the faster the frosting rate. The control module 610 can use various algorithms to calculate the frosting rate. For example, it can average the most recent N time intervals, or use weighted averaging, exponential smoothing, etc., to more accurately reflect the frosting trend under the current operating conditions. By comparison, the system can identify which heat exchange zones 130 have the fastest frosting rates, i.e., which areas are most prone to frosting or have the most severe frosting.

[0148] When multiple heat exchange zones 130 simultaneously meet the defrosting conditions, the control module 610 prioritizes defrosting the zone with the fastest frosting rate to ensure these critical areas are addressed promptly. For example, when heating multiple heat exchange zones 130 of the target area sequentially, the zone with the fastest frosting rate is placed before the defrosting sequence. Furthermore, for the heat exchange zone 130 with the fastest frosting rate, the control module 610 can instruct it to extend the heating time, continuing heating for a period even after its surface temperature has reached a preset defrosting end threshold to ensure the frost layer completely melts. This can be achieved by dynamically adjusting the defrosting end conditions, such as extending the fourth duration T4, or adding an additional preset duration after reaching the fifth threshold K5.

[0149] By dynamically acquiring and analyzing the historical frosting time intervals of 130°C in each heat exchange zone, the system can accurately calculate and compare the frosting rates of each zone, thereby intelligently identifying the zones with the fastest frosting and the highest priority for treatment. This adaptive adjustment based on the actual frosting rate allows the system to specifically increase the heating priority or extend the heating time of fast-frosting zones, ensuring that these critical zones are thoroughly defrosted and avoiding a decrease in heat exchange efficiency due to incomplete defrosting. Simultaneously, for slower-frosting zones, unnecessary over-defrosting is avoided, thereby reducing energy consumption. Overall, the defrosting control method of this application significantly improves the efficiency and thoroughness of defrosting, optimizes the overall operating energy efficiency and stability of the refrigerant circulation system, and helps extend the service life of the equipment.

[0150] Thirdly, this application also provides a heat pump unit, including the refrigerant circulation system described in the first aspect.

[0151] Fourthly, embodiments of this application also provide a control module 610, such as... Figure 10 As shown, the control module 610 includes a processor 611, a communication interface 612, a memory 613, and a communication bus 614. The processor 611, communication interface 612, and memory 613 communicate with each other via the communication bus 614. The memory 613 is used to store computer programs.

[0152] In one embodiment of this application, when the processor 611 executes a program stored in the memory 613, it implements the steps of the defrosting control method provided in any of the method embodiments of the second aspect.

[0153] Fourthly, embodiments of this application also provide a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the defrosting control method provided in any of the method embodiments of the second aspect.

[0154] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0155] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0156] The above are merely specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A refrigerant circulation system, characterized in that, include: The main evaporator includes at least two main flow channels and at least two defrost flow channels arranged in parallel. The main evaporator is provided with at least two heat exchange zones along a first direction. Each heat exchange zone is provided with one defrost flow channel and at least one main flow channel. The main circuit includes a compressor discharge end, a condenser, a first throttle, at least two main flow channels, and a compressor suction end, all connected in a loop. And a defrosting circuit, the defrosting circuit including the exhaust end of the compressor in circulation, a first electrically controlled valve, at least two defrosting channels, a second throttle, a defrosting evaporator and the suction end of the compressor; During defrosting, the main flow channel is open, and the main heat exchanger is configured such that at least one defrosting flow channel in the heat exchange zone is open between the exhaust end of the compressor and the second throttle.

2. The refrigerant circulation system according to claim 1, characterized in that, The main evaporator includes a control valve assembly, which includes at least two second electrically controlled valves. One of the second electrically controlled valves is connected to one of the defrost channels and is used to control the opening and closing state of the defrost channel; and / or, The number of the first electrically controlled valves is at least two, and the at least two first electrically controlled valves are connected to the plurality of defrosting channels in a one-to-one correspondence.

3. The refrigerant circulation system according to claim 1, characterized in that, The main evaporator includes a control valve assembly, which includes a valve body and a valve core. The valve body has a valve cavity and a liquid inlet and at least two liquid outlets connected to each other. One of the liquid outlets is connected to a defrosting channel, and the liquid inlet is connected to the first electrically controlled valve. The valve core is rotatably or slidably disposed in the valve cavity, and the valve core is configured to connect the liquid inlet and one of the liquid outlets.

4. The refrigerant circulation system according to claim 1, characterized in that, The defrosting circuit includes: A third expansion valve, connected in series with the second expansion valve on the side away from the defrosting evaporator, wherein the second expansion valve is an electronic expansion valve; and / or A first one-way valve is connected in series between the defrosting channel and the defrosting evaporator.

5. The refrigerant circulation system according to claim 1, characterized in that, The defrosting evaporator includes a first heat exchange channel and a second heat exchange channel that exchange heat with each other; in the defrosting circuit, the first heat exchange channel is connected in series between the suction end of the compressor and the second throttle. The refrigerant circulation system includes a first heating branch, which includes a second one-way valve, a second heat exchange channel, and a third electrically controlled valve arranged in series; in the main circuit during heating operation, at least a portion of the main circuit between the compressor's discharge end and the first throttle is connected in parallel with the first heating branch; and / or, The defrosting evaporator is a plate heat exchanger or a shell-and-tube heat exchanger.

6. The refrigerant circulation system according to claim 1, characterized in that, The defrosting evaporator includes a first heat exchange channel and a third heat exchange channel that exchange heat with each other; in the defrosting circuit, the first heat exchange channel is connected in series between the suction end of the compressor and the second throttle. The refrigerant circulation system includes a second heating branch, which includes a third one-way valve, the third heat exchange channel, and a fourth electrically controlled valve arranged in series. In the defrosting circuit, at least a portion of the defrosting circuit between the compressor's exhaust end and the defrosting channel is arranged in parallel with the second heating branch.

7. The refrigerant circulation system according to claim 1, characterized in that, The main evaporator is a finned heat exchanger; and / or... The main circuit includes a cooling fan, which drives airflow through the main evaporator; along the airflow direction, the main flow channel in the same heat exchange zone is located downstream of the defrosting flow channel.

8. The refrigerant circulation system according to any one of claims 1-7, characterized in that, The refrigerant circulation system includes: A first temperature sensor is installed at the exhaust end of the compressor to detect the exhaust temperature. At least two second temperature sensors are disposed in the plurality of heat exchange zones to detect the heat exchange temperature of each heat exchange zone; The third temperature sensor is used to detect the ambient temperature; The system also includes a control module electrically connected to the first temperature sensor, the second temperature sensor, and the third temperature sensor, for acquiring the exhaust temperature, multiple heat exchange temperatures, and the ambient temperature; the control module is also electrically connected to the compressor, the first throttle, the first electrically controlled valve, and the second throttle.

9. A defrosting control method for a refrigerant circulation system, used to control the refrigerant circulation system as described in any one of claims 1-8, characterized in that, The defrosting control method includes: The refrigerant circulation system is controlled to start the main circuit and switch to heating mode; Obtain the heat exchange temperature of the multiple heat exchange zones in the main evaporator; If the heat exchange temperature of at least a portion of the heat exchange zone is lower than a first threshold and the duration exceeds a first duration, that portion of the heat exchange zone is marked as a target area. The defrosting circuit is activated to sequentially heat the heat exchange zone corresponding to the target area.

10. The defrosting control method for a refrigerant circulation system according to claim 9, characterized in that, The heating sequence of the heat exchange zones corresponding to the target area is arranged in ascending order of heat exchange temperature; and / or The step of controlling the defrosting circuit to sequentially heat the heat exchange zone corresponding to the target area includes: The first electrically controlled valve is opened, and the defrosting channels corresponding to each heat exchange zone in the target area are sequentially opened.

11. The defrosting control method for a refrigerant circulation system according to claim 9, characterized in that, The second throttle is an electronic expansion valve, and the step of controlling the start of the defrosting circuit to sequentially heat the heat exchange zone corresponding to the target area includes: The exhaust temperature of the compressor is obtained, and the exhaust temperature, a second threshold, and a third threshold are compared, wherein the second threshold is greater than the third threshold. If the exhaust temperature is greater than the second threshold, the opening of the second throttle is increased by a first preset value. If the exhaust temperature is less than the third threshold, the opening of the second throttle is reduced by a second preset value. If the exhaust temperature is between the third threshold and the second threshold, when the exhaust temperature is greater than the target temperature, the opening of the second throttle is controlled to increase by a third preset value; when the exhaust temperature is less than the target temperature, the opening of the second throttle is controlled to decrease by a third preset value.

12. The defrosting control method for a refrigerant circulation system according to claim 11, characterized in that, Before obtaining the exhaust temperature, the step of controlling the defrosting circuit to sequentially heat the heat exchange zone corresponding to the target area includes: The ambient temperature is acquired, and the second throttle is controlled to switch to the corresponding initial opening based on the ambient temperature.

13. The defrosting control method for a refrigerant circulation system according to claim 11, characterized in that, The step of controlling the defrosting circuit to sequentially heat the heat exchange zone corresponding to the target area includes: If the exhaust temperature is greater than a fourth threshold, and the fourth threshold is greater than the second threshold, the opening of the second throttle is switched to 100%, and the operating frequency of the compressor is reduced; and / or, After defrosting of each heating zone corresponding to the target area is completed, the target areas are reconfirmed and sorted; and / or, If the heating temperature of the heated heat exchange zone is greater than or equal to a fifth threshold and maintained for a third duration, wherein the fifth threshold is greater than 0°C, then heating of the heat exchange zone is stopped; or... If the heating time of the heat exchange zone reaches a fourth duration, and the fourth duration is greater than 100 seconds, then heating of the heat exchange zone will stop.

14. The defrosting control method for a refrigerant circulation system according to claim 9, characterized in that, The defrosting control method includes: Obtain the time interval between two adjacent heating conditions of the heat exchange zone; The frosting rate is calculated based on multiple time intervals for each heat exchange zone, and the frosting rates of the multiple heat exchange zones are compared. If the frosting rate of the heat exchange zone exceeds a preset value, the heating priority or heating time of the heat exchange zone will be increased.

15. A heat pump unit, characterized in that, The refrigerant circulation system includes any one of claims 1-8.

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