Heat pump drying unit

Abstract

The present invention discloses a heat pump drying unit, which relates to the technical field of drying equipment and is conducive to improving the intelligence of the heat pump drying unit. The heat pump drying unit includes: a first circulation air duct, a second circulation air duct, a closed circulation flow path, an open circulation flow path and a controller. The closed circulation flow path includes a compressor, a condenser, a first throttling device and a first evaporator connected in sequence; the open circulation flow path includes a compressor, a condenser, a second throttling device and a second evaporator connected in sequence, and the second evaporator is located in the second circulation air duct; the controller is configured to: obtain the actual relative humidity of the drying room; compare the actual relative humidity with the preset relative humidity; when it is determined that the actual relative humidity is less than or equal to the preset relative humidity, control the heat pump drying unit to operate in an open operation mode, in which the compressor works and the second throttling device throttles, so that the refrigerant circulates in the open circulation flow path and does not circulate in the closed circulation flow path.

Description

Technical Field

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

[0002] In the related art, the open operation mode of the heat pump dryer unit controls the start and stop of the compressor according to the dry-bulb temperature in the drying room, so that the heat pump dryer unit can run or stop the open operation mode. The closed operation mode of the heat pump dryer unit controls the start and stop of the compressor according to the wet-bulb temperature in the drying room, so that the heat pump dryer unit can run or stop the closed operation mode. Since the existing heat pump dryer unit requires the operator to manually select whether the heat pump dryer unit adopts the open operation mode or the closed operation mode. When the heat pump dryer unit needs to run in the open operation mode in the early stage, and the operator makes a wrong choice, causing the heat pump dryer unit to run in the closed operation mode, the heat pump dryer unit will dehumidify the drying room, causing the temperature in the drying room to be too low in the early stage, so that the materials in the drying room cannot change color normally, affecting the drying quality. Summary of the invention

[0003] The embodiment of the present invention provides a heat pump drying unit, which is beneficial to improving the intelligence of the heat pump drying unit.

[0004] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0005] An embodiment of the present application provides a heat pump drying unit, comprising: a first circulation air duct, a second circulation air duct, a closed circulation flow path, an open circulation flow path and a controller. The first circulation air duct has a first air outlet and a first air return outlet, and the first air outlet and the first air return outlet are used to communicate with the drying room; the second circulation air duct has a second air outlet and a second air return outlet, and the second air outlet and the second air return outlet are used to communicate with the outside atmosphere; the closed circulation flow path includes a compressor, a condenser, a first throttling device and a first evaporator connected in sequence, and the condenser and the first evaporator are both located in the first circulation air duct; the open circulation flow path includes the compressor, the condenser, the second throttling device and the second evaporator connected in sequence, and the second evaporator is located in the second circulation air duct; the controller is configured to: obtain the actual relative humidity of the drying room; compare the actual relative humidity with the preset relative humidity; when it is determined that the actual relative humidity is less than or equal to the preset relative humidity, control the heat pump drying unit to operate in an open operation mode, in which the compressor works and the second throttling device throttles, so that the refrigerant circulates in the open circulation flow path and does not circulate in the closed circulation flow path.

[0006] The heat pump drying unit provided in the embodiment of the present application can automatically control whether the heat pump drying unit is running in an open operation mode according to the relationship between the actual relative humidity of the drying room and the preset relative humidity by obtaining the actual relative humidity of the drying room. Thereby, it is possible to avoid the use of manual control of the heat pump drying unit, which is beneficial to improving the intelligence level of the heat pump drying unit. It can also avoid the problem of wrong selection, which is beneficial to improving the reliability of the operation of the heat pump drying unit. At the same time, when the actual relative humidity is less than or equal to the preset relative humidity, the heat pump drying unit is controlled to run in an open operation mode, which can avoid the problem of too low humidity in the drying room in the early stage of the operation of the heat pump drying unit, which is beneficial to improving the efficiency and reliability of the heat pump drying unit in drying materials, and further to improving the user experience.

[0007] In some embodiments, in the open operation mode, the first throttling device is closed.

[0008] In some embodiments, the controller is configured to: when it is determined that the actual relative humidity is greater than the preset relative humidity, determine the relationship between the difference between the actual relative humidity and the preset relative humidity and the preset difference; when it is determined that the difference between the actual relative humidity and the preset relative humidity is less than or equal to the preset difference, control the heat pump drying unit to operate in an open operation mode.

[0009] In some embodiments, the controller is configured to: when it is determined that the actual relative humidity is greater than the preset relative humidity, determine the relationship between the difference between the actual relative humidity and the preset relative humidity and the preset difference; when it is determined that the difference between the actual relative humidity and the preset relative humidity is greater than the preset difference, control the heat pump drying unit to operate in a closed operation mode, in which the compressor works and the first throttling device throttles, so that the refrigerant circulates in the closed circulation flow path.

[0010] In some embodiments, in the closed operation mode, the second throttling device is closed.

[0011] In some embodiments, the controller is configured to: during the process of controlling the heat pump drying unit to operate in an open operation mode, determine the relationship between the difference between the actual relative humidity and the preset relative humidity and the preset difference; when it is determined that the difference between the actual relative humidity and the preset relative humidity is greater than the preset difference, control the heat pump drying unit to operate in a closed operation mode.

[0012] In some embodiments, there are multiple compressors, and the heat pump drying unit also includes: a dry-bulb temperature sensor for detecting the actual dry-bulb temperature in the drying room; the controller is configured to: obtain the actual dry-bulb temperature; determine the number n of the compressors corresponding to the difference interval according to the first difference interval in which the difference between the actual dry-bulb temperature and the preset dry-bulb temperature is located, and the number n of compressors corresponding to different first difference intervals is positively correlated with different first difference intervals; control the n compressors to start according to the determined number n of compressors; wherein n is greater than or equal to 1.

[0013] In some embodiments, the first circulating air duct has a fresh air inlet, which is connected to the outside atmosphere, and the condenser is located on the air supply path from the fresh air inlet to the first air outlet; an air guide plate is rotatably provided at the fresh air inlet; the heat pump drying unit includes a wet-bulb temperature sensor for detecting the actual wet-bulb temperature in the drying room; the controller is configured to: obtain the actual wet-bulb temperature; determine the opening angle of the air guide plate corresponding to the difference interval according to the second difference interval in which the difference between the actual wet-bulb temperature and the preset wet-bulb temperature lies, and the opening angle of the air guide plate corresponding to different second difference intervals is positively correlated with different second difference intervals; according to the determined opening angle of the air guide plate, control the air guide plate to rotate to the opening angle; wherein the value range of the opening angle is 0-90°.

[0014] In some embodiments, the controller is configured to: when controlling the heat pump dryer unit to switch from the open operation mode to the closed operation mode, and before controlling the heat pump dryer unit to switch to the closed operation mode, control the first throttling device to throttle and the second throttling device to throttle; and when the throttling time of the second throttling device reaches a preset time, control the second throttling device to close to enter the closed operation mode; when controlling the heat pump dryer unit to switch from the closed operation mode to the open operation mode, and before controlling the heat pump dryer unit to switch to the open operation mode, control the first throttling device to throttle and the second throttling device to throttle; and when the throttling time of the first throttling device reaches a preset time, control the first throttling device to close to enter the open operation mode.

[0015] In some embodiments, the preset relative humidity ranges from 30% to 40%. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a heat pump drying unit connected to a drying room provided in an embodiment of the present application;

[0017] Figure 2 A schematic diagram of a heat pump drying unit in a closed operation mode provided in an embodiment of the present application;

[0018] Figure 3 A schematic diagram of the heat pump drying unit provided in the embodiment of the present application in an open operation mode;

[0019] Figure 4 A schematic diagram of the structure of a heat pump drying unit provided in an embodiment of the present application;

[0020] Figure 5 A schematic diagram of the composition of a heat pump drying unit provided in an embodiment of the present application;

[0021] Figure 6 A flow chart of a first control method for a heat pump drying unit provided in an embodiment of the present application;

[0022] Figure 7 A flow chart of a second control method for a heat pump drying unit provided in an embodiment of the present application;

[0023] Figure 8 A flow chart of a third control method for a heat pump drying unit provided in an embodiment of the present application;

[0024] Fig. 9 A flowchart of a fourth control method for a heat pump drying unit provided in an embodiment of the present application;

[0025] Fig.10 A flow chart of a fifth control method for a heat pump drying unit provided in an embodiment of the present application;

[0026] Fig.11 A flow chart of the number of compressors started for a heat pump drying unit provided in an embodiment of the present application;

[0027] Fig.12 A relationship diagram between ΔTd and the number of compressors turned on provided in an embodiment of the present application;

[0028] Fig.13 A flow chart of the rotation angle of the fresh air door of the heat pump drying unit provided in the embodiment of the present application;

[0029] Fig.14 A relationship diagram between ΔTw and the opening angle of the air guide plate provided in an embodiment of the present application.

[0030] Reference numerals:

[0031] 100. Heat pump drying unit; 200. Drying room;

[0032] 1. First circulation air duct; 11. First air outlet; 12. First return air outlet;

[0033] 2. Second circulation air duct; 21. Second air outlet; 22. Second air return outlet;

[0034] 3. Compressor; 31. Exhaust port; 32. Intake port;

[0035] 4. Condenser;

[0036] 5. Closed circulation flow path; 51. First evaporator; 511. Dry-bulb temperature sensor; 512. Wet-bulb temperature sensor; 52. First throttling device;

[0037] 6. open circulation flow path; 61. second evaporator; 62. second throttling device;

[0038] 7. Heating device. DETAILED DESCRIPTION

[0039] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0040] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "bottom", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0041] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0042] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the related art, the open operation mode of the heat pump dryer unit controls the start and stop of the compressor according to the dry-bulb temperature in the drying room, so that the heat pump dryer unit can run or stop the open operation mode. The closed operation mode of the heat pump dryer unit controls the start and stop of the compressor according to the wet-bulb temperature in the drying room, so that the heat pump dryer unit can run or stop the closed operation mode. Since the existing heat pump dryer unit requires the operator to manually select whether the heat pump dryer unit adopts the open operation mode or the closed operation mode. When the heat pump dryer unit needs to run in the open operation mode in the early stage, and the operator makes a wrong choice, causing the heat pump dryer unit to run in the closed operation mode, the heat pump dryer unit will dehumidify the drying room, causing the temperature in the drying room to be too low in the early stage, so that the materials in the drying room cannot change color normally, affecting the drying quality.

[0044] In order to solve the above technical problems, by obtaining the actual relative humidity of the drying room, the heat pump drying unit can automatically control whether the heat pump drying unit is running in the open operation mode according to the relationship between the actual relative humidity of the drying room and the preset relative humidity. Thereby, it is possible to avoid the manual control of the heat pump drying unit, which is conducive to improving the intelligence of the heat pump drying unit. It can also avoid the problem of wrong selection, which is conducive to improving the reliability of the operation of the heat pump drying unit. At the same time, when the actual relative humidity is less than or equal to the preset relative humidity, controlling the heat pump drying unit to run in the open operation mode can avoid the problem of too low humidity in the drying room in the early stage of the heat pump drying unit, which is conducive to improving the efficiency and reliability of the heat pump drying unit in drying materials, and thus is conducive to improving the user experience.

[0045] The heat pump drying unit according to the embodiment of the present application is described below.

[0046] See also Figure 1 , Figure 1 A schematic diagram of a heat pump drying unit connected to a drying room provided in an embodiment of the present application. The heat pump drying unit 100 is used to dry items to be dried in a drying room 200, and the heat pump drying unit 100 includes: a first circulation duct 1, a second circulation duct 2, a closed circulation flow path 5, an open circulation flow path 6 and a controller.

[0047] Please continue reading Figure 1 The first circulation air duct 1 has a first air outlet 11 and a first air return outlet 12. The first air outlet 11 and the first air return outlet 12 are used to communicate with the drying room 200. Thus, the airflow in the first circulation air duct 1 can flow from the first air outlet 11 to the drying room 200, and then flow back from the drying room 200 to the first circulation air duct 1 through the first air return outlet 12.

[0048] In some embodiments, the heat pump drying unit 100 further includes a first fan (not shown), which is used to drive the airflow from the first return air port 12 to the first air outlet 11. Thus, the first fan can provide power for the airflow flowing from the first return air port 12 to the first air outlet 11, so that the airflow can circulate between the drying room 200 and the first circulation air duct 1. Exemplarily, the first fan is located in the first circulation air duct 1. Another exemplary embodiment is that the first fan is located outside the first circulation air duct 1, and is located at the first air outlet 11, or is located at the first return air port 12.

[0049] Please continue reading Figure 1 The second circulation air duct 2 has a second air outlet 21 and a second air return outlet 22. The second air outlet 21 and the second air return outlet 22 are used to communicate with the outside atmosphere. Thus, the airflow in the second circulation air duct 2 can flow from the second air outlet 21 to the outside, and the outside atmosphere flows into the second circulation air duct 2 through the second air return outlet 22.

[0050] In some embodiments, the heat pump drying unit 100 further includes a second fan (not shown), which is used to drive the airflow from the second return air port 22 to the second air outlet 21. Thus, the second fan can provide power for the airflow flowing from the second return air port 22 to the second air outlet 21, so that the airflow can circulate between the outside atmosphere and the second circulation air duct 2. Exemplarily, the second fan is located in the second circulation air duct 2. In another exemplary embodiment, the second fan is located outside the second circulation air duct 2, and is located at the second air outlet 21, or is located at the second return air port 22.

[0051] Please continue reading Figure 1 The closed circulation flow path 5 includes a compressor 3, a condenser 4, a first throttling device 52 and a first evaporator 51 connected in sequence. The compressor 3 has an air intake port 32 and an air discharge port 31. Specifically, the air intake port 32 of the compressor 3 is used for air intake, and the refrigerant enters the compression chamber of the compressor 3 through the air intake port 32 for compression to form a high-temperature and high-pressure refrigerant, and the high-temperature and high-pressure refrigerant gas is then discharged from the compressor 3 from the air discharge port 31 of the compressor 3. For example, the compressor 3 can be a scroll compressor, a rotor compressor, a screw compressor, etc.

[0052] In some embodiments, there are multiple compressors 3. By providing multiple compressors 3, the drying efficiency of the heat pump drying unit 100 can be improved.

[0053] Please continue reading Figure 1 , the condenser 4 and the first evaporator 51 are both located in the first circulation air duct 1. Therefore, when the airflow in the first circulation air duct 1 flows through the condenser 4, the condenser 4 can heat the airflow flowing therethrough. When the airflow in the first circulation air duct 1 flows through the first evaporator 51, the first evaporator 51 can cool and dehumidify the airflow flowing therethrough, so that the water in the airflow is analyzed out.

[0054] Please continue reading Figure 1 The first throttling device 52 can throttle and reduce the pressure of the refrigerant flowing through. Exemplarily, the first throttling device 52 can be a capillary tube, a throttle valve, an electronic expansion valve, or a thermal expansion valve.

[0055] In some embodiments, the first evaporator 51 and the condenser 4 are arranged in sequence in the air flow direction in the first circulation air duct 1, and the first evaporator 51 is located upstream of the condenser 4. This arrangement allows the airflow flowing out of the first return air port 12 to first pass through the first evaporator 51 to reduce humidity, then flow through the condenser 4 to increase temperature, and the heated airflow is sent into the drying room 200 through the first air outlet 11.

[0056] Please continue reading Figure 1 The open circulation flow path 6 includes a compressor 3, a condenser 4, a second throttling device 62 and a second evaporator 61 connected in sequence. The second evaporator 61 is located in the second circulation air duct 2. As a result, the outside air flows into the second evaporator 61 from the second return air port 22. Since the second evaporator 61 can evaporate and absorb heat, the second evaporator 61 can absorb heat from the outside air flowing in. The airflow after heat exchange flows back to the outside from the second air outlet 21.

[0057] Please continue reading Figure 1 The second throttling device 62 can throttle and reduce the pressure of the refrigerant flowing through. Exemplarily, the second throttling device 62 can be a capillary tube, a throttling valve, an electronic expansion valve or a thermal expansion valve.

[0058] The heat pump drying unit 100 provided in the embodiment of the present application has two operating modes: an open operation mode and a closed operation mode. The open operation mode and the closed operation mode of the heat pump drying unit 100 provided in the embodiment of the present application are described below.

[0059] See also Figure 2 , Figure 2 A schematic diagram of a heat pump drying unit in a closed operation mode provided in an embodiment of the present application. When the heat pump drying unit 100 is in a closed operation mode, the controller controls the compressor 3 to work and the first throttling device 52 to throttle, so that the refrigerant flows in the closed circulation flow path 5 and does not circulate in the closed circulation flow path 5.

[0060] Refrigerant flow direction: The high-temperature and high-pressure gaseous refrigerant discharged from the air intake port 32 of the compressor 3 flows into the condenser 4, and becomes a high-temperature and medium-pressure liquid refrigerant after sufficient heat exchange in the condenser 4. Then the refrigerant flowing out of the condenser 4 flows to the first throttling device 52, and the refrigerant is transformed into a low-temperature and low-pressure two-phase refrigerant through the throttling and pressure reduction effect of the first throttling device 52. The refrigerant flowing out of the first throttling device 52 flows to the first evaporator 51, and becomes a low-temperature and low-pressure gaseous refrigerant after heat exchange in the first evaporator 51. Finally, it flows back from the first evaporator 51 to the air intake port 32 of the compressor 3.

[0061] At this time, the airflow in the first circulation air duct 1 first flows through the first evaporator 51 during the process of flowing from the first return air port 12 to the first air outlet 11. The first evaporator 51 evaporates and absorbs heat, so that the water in the airflow is analyzed and the airflow is cooled and dehumidified. Then the airflow flows through the condenser 4, which condenses and releases heat to heat the airflow passing through.

[0062] See also Figure 3 , Figure 3 A schematic diagram of the heat pump drying unit 100 in the open operation mode provided in the embodiment of the present application. When the heat pump drying unit 100 is in the open operation mode, the controller controls the compressor 3 to work and the second throttling device 62 to throttle, so that the refrigerant flows in the open circulation flow path 6 and does not circulate in the closed circulation flow path 5.

[0063] Refrigerant flow direction: The high-temperature and high-pressure gaseous refrigerant discharged from the air intake port 32 of the compressor 3 flows into the condenser 4, and becomes a high-temperature and medium-pressure liquid refrigerant after sufficient heat exchange in the condenser 4. Then the refrigerant flowing out of the condenser 4 flows to the second throttling device 62, and the refrigerant is transformed into a low-temperature and low-pressure two-phase refrigerant through the throttling and pressure reduction effect of the second throttling device 62. The refrigerant flowing out of the second throttling device 62 flows to the second evaporator 61, and becomes a low-temperature and low-pressure gaseous refrigerant after heat exchange in the second evaporator 61. Finally, it flows back from the second evaporator 61 to the air intake port 32 of the compressor 3.

[0064] At this time, when the airflow in the first circulation air duct 1 flows from the first return air port 12 to the first air outlet 11, since no refrigerant flows through the first evaporator 51, the first evaporator 51 does not have the function of cooling and dehumidifying. However, when the refrigerant flows through the condenser 4, the airflow can be heated when flowing through the condenser 4.

[0065] At this time, when the airflow in the second circulation air duct 2 flows from the second return air port 22 to the second air outlet 21, the outside atmosphere exchanges heat with the second evaporator 61, and the second evaporator 61 absorbs heat from the outside atmosphere. After the heat exchange is completed, the airflow flows out from the second air outlet 21.

[0066] See also Figure 4 , Figure 4The schematic diagram of the structure of the heat pump drying unit provided in the embodiment of the present application. In some implementations, the heat pump drying unit 100 further includes a heating device 7. The heating device 7 is located in the first circulation air duct 1 and between the condenser 4 and the first air outlet 11. Such a configuration can heat the airflow passing through the heating device 7, which is conducive to improving the heating efficiency of the heat pump drying unit 100.

[0067] Exemplarily, the heating device 7 may be a resistance wire, an electric heating wire, or the like.

[0068] In some embodiments, there are multiple heating devices 7. By providing multiple heating devices 7, the heating efficiency of the heat pump drying unit 100 on the airflow can be further improved.

[0069] In some embodiments, the first circulating air duct 1 has a fresh air inlet (not shown in the figure), the fresh air inlet is connected to the outside atmosphere, and the condenser 4 is located on the air supply path from the fresh air inlet to the first air outlet 11. Therefore, the outside atmosphere can enter the first circulating air duct 1 through the fresh air inlet, and after heat exchange in the condenser 4, can flow into the drying room 200.

[0070] In some embodiments, a wind deflector is rotatably provided at the fresh air inlet (as shown in the figure). This arrangement can control the size of the air flow entering the first circulation air duct 1 from the fresh air outlet by controlling the rotation angle of the wind deflector.

[0071] In some embodiments, a dry bulb temperature sensor 511 and a wet bulb temperature sensor 512 may be connected to the controller. The dry bulb temperature sensor 511 is used to detect the actual dry bulb temperature in the drying room 200, and the wet bulb thermometer is used to detect the actual wet bulb temperature in the drying room 200.

[0072] See also Figure 5 , Figure 5 A schematic diagram of the composition of the heat pump drying unit provided in the embodiment of the present application. In some embodiments, the dry-bulb temperature sensor 511 and the wet-bulb temperature sensor 512 can be arranged on one side of the first evaporator 51 and located in the first circulation air duct 1. Such an arrangement is conducive to improving the accuracy of the detection of the dry-bulb temperature sensor 511 and the wet-bulb temperature sensor 512.

[0073] In other embodiments, the dry-bulb temperature sensor 511 and the wet-bulb temperature sensor 512 may be disposed in the drying room 200, and the dry-bulb temperature sensor 511 may be wirelessly connected to the controller. The wet-bulb thermometer may be wirelessly connected to the controller. Such an arrangement is conducive to improving the accuracy of the detection of the dry-bulb temperature sensor 511 and the wet-bulb temperature sensor 512.

[0074] In some embodiments, the heat pump drying unit 100 further includes a relative humidity sensor, which can be connected to the controller. The relative humidity sensor is used to detect the relative humidity in the drying room 200. This arrangement facilitates the measurement of relative humidity, which is beneficial to improving the reliability of the operation of the heat pump drying unit 100.

[0075] In other embodiments, the relative humidity may be calculated based on the dry-bulb temperature and the wet-bulb temperature detected by the dry-bulb temperature sensor 511 and the wet-bulb temperature sensor 512 .

[0076] In addition, the controller can be used to control the operation of various components inside the heat pump drying unit 100 , so that various components in the heat pump drying unit 100 can operate to realize various predetermined functions of the heat pump drying unit 100 .

[0077] Based on the structure of the heat pump drying system described above, the control method of the heat pump drying unit 100 according to the embodiment of the present application is described below. The method is applied to a controller, which may be the controller described above.

[0078] See also Figure 6 , Figure 6 This is a flow chart of a first control method of a heat pump drying unit provided in an embodiment of the present application. The control method of the heat pump drying unit 100 includes:

[0079] S1: Acquire the actual relative humidity of the drying room 200. The actual relative humidity in the drying room 200 may be acquired through a relative humidity sensor.

[0080] S2: Compare the actual relative humidity with the preset relative humidity. Thus, the relationship between the actual relative humidity and the preset relative humidity can be determined.

[0081] S3: When it is determined that the actual relative humidity is less than or equal to the preset relative humidity, the heat pump drying unit 100 is controlled to operate in the open operation mode. In the open operation mode, the compressor 3 works and the second throttling device 62 throttles, so that the refrigerant circulates in the open circulation flow path 6 and does not circulate in the closed circulation flow path 5. In this way, it is possible to avoid the refrigerant from flowing in the closed circulation flow path 5 when the heat pump drying unit 100 operates in the open operation mode.

[0082] According to the control method of the heat pump drying unit 100 of the embodiment of the present invention, by obtaining the actual relative humidity of the drying room 200, the heat pump drying unit 100 can automatically control whether the heat pump drying unit 100 runs in the open operation mode according to the relationship between the actual relative humidity of the drying room 200 and the preset relative humidity. Thus, it is possible to avoid the use of manual control of the heat pump drying unit 100, which is conducive to improving the intelligence of the heat pump drying unit 100. And it can also avoid the problem of wrong selection, which is conducive to improving the reliability of the operation of the heat pump drying unit 100. At the same time, when the actual relative humidity is less than or equal to the preset relative humidity, the heat pump drying unit 100 is controlled to run in the open operation mode, which can avoid the problem of too low humidity in the drying room 200 in the early stage of the operation of the heat pump drying unit 100, which is conducive to improving the efficiency and reliability of the heat pump drying unit 100 in drying materials, and thus is conducive to improving the user experience.

[0083] In some embodiments, in the open operation mode, the first throttling device 52 is closed. Thus, by closing the first throttling device 52, it is possible to avoid the heat pump flowing in the closed circulation flow path 5 when the heat pump drying unit 100 is in the open operation mode, which is beneficial to improving the reliability of the operation of the heat pump drying unit 100.

[0084] In some embodiments, when it is determined that the actual relative humidity is greater than the preset relative humidity, the heat pump drying unit 100 can be directly controlled to operate in a closed operation mode.

[0085] See also Figure 7 , Figure 7 This is a flow chart of a second control method for a heat pump drying unit provided in an embodiment of the present application. The method comprises:

[0086] S1: Acquire the actual relative humidity of the drying room 200.

[0087] S2: Compare the actual relative humidity with the preset relative humidity.

[0088] S3: When it is determined that the actual relative humidity is greater than the preset relative humidity, the relationship between the difference △T between the actual relative humidity and the preset relative humidity and the preset difference is determined; therefore, when the actual relative humidity is greater than the preset relative humidity, it means that the humidity value in the drying room 200 is relatively high. By further determining the relationship between the difference △T between the actual relative humidity and the preset relative humidity and the preset difference, the humidity value in the drying room 200 can be further accurately determined, so that the working mode of the heat pump drying unit 100 can be reasonably selected, which is beneficial to improving the drying efficiency of the heat pump drying unit 100.

[0089] S4: When it is determined that the difference △T between the actual relative humidity and the preset relative humidity is less than or equal to the preset difference, the heat pump drying unit 100 is controlled to operate in the open operation mode. Therefore, when the difference △T between the actual relative humidity and the preset relative humidity is less than or equal to the preset difference, it means that the humidity in the drying room 200 is low at this time, so that the heat pump drying unit 100 can be prevented from operating in the closed operation mode, dehumidifying the drying room 200, making the humidity in the drying room 200 lower, and affecting the drying quality of the material. It is also beneficial to improve the drying efficiency of the heat pump drying unit 100 for the material, so that the material can be dried better.

[0090] See also Figure 8 , Figure 8 This is a flow chart of a third control method for a heat pump drying unit provided in an embodiment of the present application. The method comprises:

[0091] S1: Acquire the actual relative humidity of the drying room 200.

[0092] S2: Compare the actual relative humidity with the preset relative humidity.

[0093] S3: when it is determined that the actual relative humidity is greater than the preset relative humidity, determining the magnitude relationship between the difference △T between the actual relative humidity and the preset relative humidity and the preset difference;

[0094] S4: When it is determined that the difference △T between the actual relative humidity and the preset relative humidity is greater than the preset difference, the heat pump drying unit 100 is controlled to operate in a closed operation mode. In the closed operation mode, the compressor 3 works and the first throttling device 52 throttles, so that the refrigerant circulates in the closed circulation flow path 5. Therefore, when the difference △T between the actual relative humidity and the preset relative humidity is greater than the preset difference, it means that the humidity in the drying room 200 is relatively high at this time. By making the heat pump drying unit 100 operate in a closed operation mode, the drying room 200 is dehumidified, so that the humidity in the drying room 200 can be controlled, and the excessive humidity in the drying room 200 can be avoided to affect the drying of the materials, which is conducive to improving the drying efficiency of the heat pump drying unit 100.

[0095] In some embodiments, in the closed operation mode, the second throttling device 62 is closed. Thus, by closing the second throttling device 62, it is possible to avoid the heat pump flowing in the open circulation flow path 6 when the heat pump drying unit 100 is in the closed operation mode, which is beneficial to improving the reliability of the operation of the heat pump drying unit 100.

[0096] See also Fig. 9 , Fig. 9 This is a flow chart of a fourth control method for a heat pump drying unit provided in an embodiment of the present application. The method comprises:

[0097] In the process of controlling the heat pump drying unit 100 to operate in the open operation mode, determining the magnitude relationship between the difference △T between the actual relative humidity and the preset relative humidity and the preset difference;

[0098] When it is determined that the difference ΔT between the actual relative humidity and the preset relative humidity is greater than the preset difference, the heat pump drying unit 100 is controlled to operate in a closed operation mode. In this way, it is possible to avoid excessive humidity in the drying room 200 affecting the drying of materials, thereby facilitating the operation reliability of the heat pump drying unit 100.

[0099] See also Fig.10 , Fig.10 This is a flow chart of a fifth control method for a heat pump drying unit provided in an embodiment of the present application. The method includes:

[0100] In the process of controlling the heat pump drying unit 100 to operate in the closed operation mode, determining the magnitude relationship between the difference △T between the actual relative humidity and the preset relative humidity and the preset difference;

[0101] When it is determined that the difference ΔT between the actual relative humidity and the preset relative humidity is less than or equal to the preset difference, the heat pump drying unit 100 is controlled to operate in the open operation mode. Thus, when the materials in the drying room 200 are close to the end of drying, the open operation mode can be adopted, and the dry bulb temperature in the drying room 200 rises faster, which is conducive to improving the drying efficiency of the heat pump drying unit 100, and can also reduce the energy consumption of the heat pump drying unit 100, which is conducive to improving the user experience.

[0102] In some embodiments, when controlling the heat pump drying unit 100 to switch from the open operation mode to the closed operation mode, and before controlling the heat pump drying unit 100 to switch to the closed operation mode, the first throttling device 52 and the second throttling device 62 are controlled to throttle. When the throttling time of the second throttling device 62 reaches the preset time, the second throttling device 62 is controlled to be closed to enter the closed operation mode. This setting can avoid the problem that the refrigerant in the pipeline cannot flow during the opening of the first throttling device 52, causing damage to the compressor 3. It is conducive to improving the safety and reliability of the operation of the heat pump drying unit 100.

[0103] When controlling the heat pump drying unit 100 to switch from the closed operation mode to the open operation mode, and before controlling the heat pump drying unit 100 to switch to the open operation mode, the first throttling device 52 and the second throttling device 62 are controlled to throttle; and when the throttling time of the first throttling device 52 reaches the preset time, the first throttling device 52 is controlled to be closed to enter the open operation mode. This setting can avoid the problem that the refrigerant in the pipeline cannot flow during the opening of the second throttling device 62, causing damage to the compressor 3. It is beneficial to improve the safety and reliability of the operation of the heat pump drying unit 100.

[0104] Please refer to Fig.11 , Fig.11 which is a flowchart of the number of compressors 3 started by the heat pump drying unit provided in the embodiment of the present application.

[0105] S1: Obtain the actual dry-bulb temperature;

[0106] S2: Determine the number n of compressors 3 corresponding to the first difference interval according to the difference ΔTd between the actual dry-bulb temperature and the preset dry-bulb temperature. The number n of compressors 3 corresponding to different first difference intervals and different first difference intervals have a positive correlation.

[0107] S3: Control n compressors 3 to start according to the determined number n of compressors 3.

[0108] Wherein, n is greater than or equal to 1.

[0109] Thus, by setting the number n of compressors 3 corresponding to the first difference interval, the heat pump drying unit 100 can determine the number of compressors 3 to be started according to the first difference interval where the difference ΔTd between the actual dry-bulb temperature and the preset dry-bulb temperature is located, so that the heat pump drying unit 100 can control the number of compressors 3 started according to the drying material demand in the drying chamber 200, which is beneficial to improving the energy efficiency and drying efficiency of the heat pump drying unit 100.

[0110] Please refer to Fig.12 , Fig.12 which is a relationship diagram of ΔTd and the number of compressors 3 started in the embodiment of the present application. Exemplarily, multiple first difference intervals can be (0, a), [a, b), [b, c), [c, d), [d, e) respectively, where a < b < c < d < e. When the first difference interval is (0, a), the number of compressors 3 started can be 1; when the first difference interval is [a, b), the number of compressors 3 started can be 2; when the first difference interval is [b, c), the number of compressors 3 started can be 3; when the first difference interval is [c, d), the number of compressors 3 started can be 4. For example, when it is determined that the first difference interval where the difference ΔTd between the actual dry-bulb temperature and the preset dry-bulb temperature is located is [a, b), and the obtained number of compressors 3 started corresponding to it is 2, then control 2 compressors 3 to start.

[0111] Please refer to Fig.13 , Fig.13 which is a flowchart of the rotation angle of the fresh air door of the heat pump drying unit provided in the embodiment of the present application.

[0112] S1: Obtain the actual wet-bulb temperature;

[0113] S2: Determine the opening angle α of the air deflector corresponding to the second difference range according to the difference ΔTw between the actual wet-bulb temperature and the preset wet-bulb temperature. The opening angle α of the air deflector corresponding to different second difference ranges is positively correlated with different second difference ranges.

[0114] S3: Control the air deflector to rotate to the opening angle α according to the determined opening angle of the air deflector.

[0115] Among them, the value range of the opening angle is 0 - 90°, and the preset wet-bulb temperature is less than the first wet-bulb setting temperature.

[0116] Thus, by setting the opening angle of the air deflector corresponding to the second difference range, the heat pump drying unit 100 can determine the opening angle α of the air deflector corresponding to the second difference range according to the difference ΔTw between the actual wet-bulb temperature and the preset wet-bulb temperature, so that the heat pump drying unit 100 can control the rotation angle of the air deflector according to the fresh air demand of the dried material in the drying chamber 200, which is beneficial to improving the energy efficiency and drying efficiency of the heat pump drying unit 100.

[0117] Please refer to Fig.14 , Fig.14 which is the relationship diagram of ΔTw and the opening angle of the air deflector provided by the embodiment of the present application. Exemplarily, multiple second difference ranges can be respectively (0, a), [a, b), [b, c), [c, d), [d, e), where a < b < c < d < e. When the second difference range is (0, a), the opening angle of the air deflector can be 15°; when the second difference range is [a, b), the opening angle of the air deflector can be 45°; when the second difference range is [b, c), the opening angle of the air deflector can be 60°; when the second difference range is [c, d), the opening angle of the air deflector can be 75°. For example, when it is determined that the second difference range where the difference ΔTw between the actual wet-bulb temperature and the preset wet-bulb temperature is located is [a, b), and the obtained opening angle of the corresponding air deflector is 45°, then control the air deflector to rotate 45°.

[0118] In some embodiments, the value range of the preset relative humidity is 30 - 40%. By setting the value range of the preset relative humidity, it is beneficial to improve the reliability of the heat pump drying unit 100. For example, the value of the preset relative humidity can be 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39% or 40%, etc.

[0119] In some embodiments, the value range of the first difference interval is [-2, 2] ° C. For example, the value of the first preset difference can be -0.1 ° C, -0.2 ° C, -0.4 ° C, -0.6 ° C, -0.8 ° C, -1 ° C, -1.1 ° C, -1.2 ° C, -1.4 ° C, -1.6 ° C, -1.8 ° C, -2 ° C, 0.1 ° C, 0.2 ° C, 0.4 ° C, 0.6 ° C, 0.8 ° C, 1 ° C, 1.1 ° C, 1.2 ° C, 1.4 ° C, 1.6 ° C, 1.8 ° C or 2 ° C. By setting the value range of the first difference interval, it is beneficial to improve the reliability of the heat pump drying unit 100.

[0120] In some embodiments, the value range of the second difference interval is (-∞, -0.5]°C. By setting the value range of the second difference interval, it is helpful to improve the reliability of the heat pump drying unit 100.

[0121] The controller includes a processor, and optionally, also includes a memory and a communication interface connected to the processor. The processor, the memory and the communication interface are connected via a bus.

[0122] The processor may be a central processing unit (CPU), a general-purpose processor network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The processor may also be any other device having a processing function, such as a circuit, a device, or a software module. The processor may also include multiple CPUs, and the processor may be a single-CPU processor or a multi-CPU processor. The processor here may refer to one or more devices, circuits, or processing cores for processing data (such as computer program instructions).

[0123] The memory may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of an instruction or data structure and can be accessed by a computer, and the present embodiment of the application does not impose any restrictions on this. The memory may exist independently or be integrated with the processor. Among them, the memory may contain a computer program code. The processor is used to execute the computer program code stored in the memory, so as to realize a control method of a heat pump drying unit 100 provided in the embodiment of the present application.

[0124] The communication interface can be used to communicate with other devices or communication networks (such as Ethernet, radio access network (RAN), wireless local area networks (WLAN), etc.). The communication interface can be a module, a circuit, a transceiver or any device that can achieve communication.

[0125] The bus may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc.

[0126] An embodiment of the present invention further provides a computer-readable storage medium, which includes computer-executable instructions. When the computer-executable instructions are executed on a computer, the computer executes a control method for a heat pump drying unit 100 provided in the above embodiment.

[0127] The embodiment of the present invention further provides a computer program product, which can be directly loaded into a memory and contains software code. After being loaded and executed by a computer, the computer program product can implement a control method of a heat pump drying unit 100 provided in the above embodiment. In the description of this specification, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0128] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0129] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A heat pump drying unit, used for drying articles to be dried in a drying room, characterized in that: include: A first circulating air duct, wherein the first circulating air duct has a first air outlet and a first air return outlet, wherein the first air outlet and the first air return outlet are used to communicate with the drying room; The first circulating air duct has a fresh air inlet, which is connected to the outside atmosphere; an air guide plate is rotatably provided at the fresh air inlet; A second circulation air duct, wherein the second circulation air duct has a second air outlet and a second air return outlet, and the second air outlet and the second air return outlet are used to communicate with the outside atmosphere; A closed circulation flow path, comprising a compressor, a condenser, a first throttling device and a first evaporator connected in sequence, wherein the condenser and the first evaporator are both located in the first circulation air duct; An open circulation flow path, comprising the compressor, the condenser, the second throttling device and the second evaporator connected in sequence, wherein the second evaporator is located in the second circulation air duct; The condenser is located on an air supply path from the fresh air inlet to the first air outlet; A dry bulb temperature sensor, used to detect the actual temperature of the dry bulb in the drying room; A wet-bulb temperature sensor, used to detect the actual wet-bulb temperature in the drying room; The controller is configured as: Obtaining the actual relative humidity of the drying room; comparing the actual relative humidity with a preset relative humidity; When it is determined that the actual relative humidity is less than or equal to the preset relative humidity, the heat pump drying unit is controlled to operate in an open operation mode, in which the compressor is operated and the second throttling device is throttled, so that the refrigerant circulates in the open circulation flow path and does not circulate in the closed circulation flow path; Get the actual dry bulb temperature; According to the first difference interval in which the difference between the actual dry-bulb temperature and the preset dry-bulb temperature is located, the number n of the compressors corresponding to the difference interval is determined, and the number n of the compressors corresponding to different first difference intervals is positively correlated with different first difference intervals; According to the determined number n of the compressors, controlling n of the compressors to start; Wherein, n is greater than or equal to 1; Get the actual wet bulb temperature; According to the second difference interval in which the difference between the actual wet-bulb temperature and the preset wet-bulb temperature is located, determining the opening angle of the air guide plate corresponding to the difference interval, and the opening angle of the air guide plate corresponding to different second difference intervals is positively correlated with different second difference intervals; According to the determined opening angle of the air deflector, controlling the air deflector to rotate to the opening angle; Among them, the value range of the opening angle is 0-90°; When it is determined that the actual relative humidity is greater than the preset relative humidity, determining a magnitude relationship between a difference between the actual relative humidity and the preset relative humidity and a preset difference; When it is determined that the difference between the actual relative humidity and the preset relative humidity is greater than the preset difference, the heat pump drying unit is controlled to operate in a closed operation mode, in which the compressor operates and the first throttling device throttles, so that the refrigerant circulates in the closed circulation flow path; When controlling the heat pump drying unit to switch from the open operation mode to the closed operation mode, and before controlling the heat pump drying unit to switch to the closed operation mode, controlling the first throttling device to throttle and the second throttling device to throttle; and when the throttling time of the second throttling device reaches a preset time, controlling the second throttling device to close to enter the closed operation mode; When controlling the heat pump dryer unit to switch from the closed operation mode to the open operation mode, and before controlling the heat pump dryer unit to switch to the open operation mode, the first throttling device is controlled to throttle and the second throttling device is controlled to throttle; and when the throttling time of the first throttling device reaches a preset time, the first throttling device is controlled to close to enter the open operation mode.

2. The heat pump drying unit according to claim 1, characterized in that: In the open operation mode, the first throttling device is closed.

3. The heat pump drying unit according to claim 1, characterized in that: The controller is configured to: When it is determined that the actual relative humidity is greater than the preset relative humidity, determining a magnitude relationship between a difference between the actual relative humidity and the preset relative humidity and a preset difference; When it is determined that the difference between the actual relative humidity and the preset relative humidity is less than or equal to the preset difference, the heat pump drying unit is controlled to operate in an open operation mode.

4. The heat pump drying unit according to claim 1, characterized in that: In the closed operating mode, the second throttle device is closed.

5. The heat pump drying unit according to claim 1, characterized in that: The controller is configured to: In the process of controlling the heat pump drying unit to operate in the open operation mode, determining the magnitude relationship between the difference between the actual relative humidity and the preset relative humidity and the preset difference; When it is determined that the difference between the actual relative humidity and the preset relative humidity is greater than the preset difference, the heat pump drying unit is controlled to operate in a closed operation mode.

6. The heat pump drying unit according to claim 1, characterized in that: The preset relative humidity ranges from 30% to 40%.

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