Heat pump drying unit and control method of heat pump drying unit

Abstract

The present invention discloses a heat pump drying unit and a control method for the heat pump drying unit, which relate to the technical field of drying equipment and are beneficial to improving the applicability of the heat pump drying unit. The heat pump drying unit comprises: a circulating air duct, a compressor, a first heat exchanger, a second heat exchanger, a dry-bulb temperature sensor, a wet-bulb temperature sensor and a controller, the circulating air duct has an air outlet and a return air outlet, the air outlet and the return air outlet are used to communicate with a drying room, the first heat exchanger and the second heat exchanger are located in the circulating air duct, the dry-bulb temperature sensor is used to detect the actual dry-bulb temperature in the drying room, the wet-bulb temperature sensor is used to detect the actual wet-bulb temperature in the drying room, and the controller is configured to: obtain the actual dry-bulb temperature and the actual wet-bulb temperature, and determine whether the compressor is started according to the relationship between the difference △Td between the actual dry-bulb temperature and the first dry-bulb setting temperature and the first preset difference, and the relationship between the difference △Tw between the actual wet-bulb temperature and the first wet-bulb setting temperature and the second preset difference.

Description

Technical Field

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

[0002] In the related art, the closed heat pump drying unit controls the start and stop of the compressor by the dry bulb temperature. Since the closed heat pump drying unit dehumidifies the airflow in the drying room during operation, when the drying material needs to be moisturized in the early stage of drying, the start of the compressor will cause the humidity in the drying room to be too low, affecting the drying quality of the drying material. Summary of the invention

[0003] The embodiments of the present invention provide a heat pump drying unit and a control method for the heat pump drying unit, which are beneficial to improving the applicability of the heat pump drying unit.

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

[0005] The first aspect of the present application provides a heat pump drying unit, comprising: a circulating air duct, a compressor, a first heat exchanger, a second heat exchanger, a dry-bulb temperature sensor, a wet-bulb temperature sensor and a controller, wherein the circulating air duct has an air outlet and a return air outlet, and the air outlet and the return air outlet are used to communicate with the drying room; the first heat exchanger is located in the circulating air duct, and one end of the first heat exchanger is connected to the compressor; the second heat exchanger is located in the circulating air duct, and one end of the second heat exchanger is connected to the other end of the first heat exchanger through a first throttling device, and the other end of the second heat exchanger is connected to the compressor; the dry-bulb temperature sensor is used to detect the actual dry-bulb temperature in the drying room; the wet-bulb temperature sensor is used to detect the actual wet-bulb temperature in the drying room; the controller is configured to: obtain the actual dry-bulb temperature and the actual wet-bulb temperature; determine whether the compressor is started according to the relationship between the difference △Td between the actual dry-bulb temperature and the first dry-bulb set temperature and the first preset difference, and the relationship between the difference △Tw between the actual wet-bulb temperature and the first wet-bulb set temperature and the second preset difference.

[0006] The heat pump drying unit provided in the embodiment of the present application obtains the actual dry-bulb temperature and the actual wet-bulb temperature in the drying room, and controls the start-up of the compressor according to the relationship between the difference between the actual dry-bulb temperature and the first dry-bulb set temperature and the first preset difference, as well as the relationship between the difference between the actual wet-bulb temperature and the first wet-bulb set temperature and the second preset difference, thereby avoiding starting the compressor when the humidity in the drying room is too low. This can improve the drying quality of the heat pump drying unit for drying materials that require preliminary moisturizing to a certain extent, and is beneficial to improving the applicability and reliability of the heat pump drying unit.

[0007] In some embodiments, the controller is configured to control the compressor to start when the difference △Td between the actual dry-bulb temperature and the first dry-bulb set temperature is less than or equal to the first preset difference, and the difference △Tw between the actual wet-bulb temperature and the first wet-bulb set temperature is greater than the second preset difference.

[0008] In some embodiments, it also includes: a heating device, which is located in the circulating air duct and between the first heat exchanger and the air outlet; the controller is also configured to: if the difference △Td between the actual dry-bulb temperature and the first dry-bulb set temperature is less than or equal to the first preset difference, and the difference △Tw between the actual wet-bulb temperature and the first wet-bulb set temperature is less than or equal to the second preset difference, control the heating device to start and the compressor to stop.

[0009] In some embodiments, the controller is configured to: after the compressor is started, determine whether the difference △Td between the actual dry-bulb temperature and the first dry-bulb set temperature is greater than a first preset difference; if the difference △Td between the first dry-bulb set temperature and the actual dry-bulb temperature is less than the first preset difference, control the heating device to start.

[0010] In some embodiments, there are multiple compressors; the controller is configured to: determine the number n of the compressors corresponding to the first difference interval in which the difference △Td between the actual dry-bulb temperature and the first dry-bulb set 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 start-up of n compressors according to the determined number n of compressors; wherein n is greater than or equal to 1.

[0011] In some embodiments, the circulating air duct has a fresh air inlet, which is connected to the outside atmosphere, and the first heat exchanger is located on the air supply path from the fresh air inlet to the air outlet; an air guide plate is rotatably provided at the fresh air inlet; the controller is configured to: determine the opening angle of the air guide plate corresponding to the second difference interval according to the second difference interval in which the difference △Tw between the actual wet-bulb temperature and the second wet-bulb set temperature is located, 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°, and the second wet-bulb set temperature is less than the first wet-bulb set temperature.

[0012] In some embodiments, there are multiple heating devices; the controller is configured to: determine the number z of the heating devices corresponding to the third difference interval according to the third difference interval in which the difference △Td between the actual dry-bulb temperature and the second dry-bulb set temperature is located, and the number z of the heating devices corresponding to different third difference intervals is positively correlated with different third difference intervals; according to the determined number z of the heating devices, control z of the heating devices to turn on; wherein, z is greater than or equal to 1, and the second dry-bulb set temperature is greater than the first dry-bulb set temperature.

[0013] In some embodiments, the first preset difference value has a value range of (0, 2]°C.

[0014] In some embodiments, the second preset difference value ranges from [-2, 0)°C.

[0015] The second aspect of the present invention provides a control method for a heat pump drying unit, comprising: a circulating air duct, a compressor, a first heat exchanger, a second heat exchanger, a dry-bulb temperature sensor, a wet-bulb temperature sensor and a controller, wherein the circulating air duct has an air outlet and a return air outlet, and the air outlet and the return air outlet are used to communicate with the drying room; the first heat exchanger is located in the circulating air duct, and one end of the first heat exchanger is connected to the compressor; the second heat exchanger is located in the circulating air duct, and one end of the second heat exchanger is connected to the other end of the first heat exchanger through a first throttling device, and the other end of the second heat exchanger is connected to the compressor; the dry-bulb temperature sensor is used to detect the actual dry-bulb temperature in the drying room; the wet-bulb temperature sensor is used to detect the actual wet-bulb temperature in the drying room; the method comprises: obtaining the actual dry-bulb temperature and the actual wet-bulb temperature; determining whether the compressor is started according to the relationship between the difference △Td between the actual dry-bulb temperature and the first dry-bulb set temperature and the first preset difference, and the relationship between the difference △Tw between the actual wet-bulb temperature and the first wet-bulb set temperature and the second preset difference.

[0016] The beneficial effects that can be produced by the control method of the above-mentioned heat pump drying unit are the same as the beneficial effects of the above-mentioned heat pump drying unit, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the structure of a heat pump drying unit provided in an embodiment of the present application;

[0018] Figure 2 A schematic diagram of a heat pump drying unit connected to a drying room provided in an embodiment of the present application;

[0019] Figure 3 A schematic diagram of the operating mode of the heat pump drying unit provided in the embodiment of the present application;

[0020] Figure 4 A schematic diagram of the structure of another heat pump drying unit provided in an embodiment of the present application;

[0021] Figure 5 A schematic diagram of another heat pump drying unit provided in an embodiment of the present application;

[0022] Figure 6 A flow chart of a first control method for a heat pump drying unit provided in an embodiment of the present application;

[0023] Figure 7 A flow chart of a second control method for a heat pump drying unit provided in an embodiment of the present application;

[0024] Figure 8 A flow chart of a third control method for a heat pump drying unit provided in an embodiment of the present application;

[0025] Fig. 9 A flowchart of a fourth control method for a heat pump drying unit provided in an embodiment of the present application;

[0026] Fig.10 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.11 A relationship diagram between ΔTd and the number of compressors turned on provided in an embodiment of the present application;

[0028] Fig.12 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.13 A relationship diagram between ΔTw and the opening angle of the air guide plate provided in an embodiment of the present application;

[0030] Fig.14 A flow chart of the number of heating devices started by a heat pump drying unit provided in an embodiment of the present application;

[0031] Fig.15 A relationship diagram between ΔTd and the number of heating devices turned on provided in an embodiment of the present application.

[0032] Reference numerals:

[0033] 100. Heat pump drying unit; 200. Drying room;

[0034] 1. Circulation air duct; 11. Air outlet; 12. Return air outlet;

[0035] 2. Compressor; 21. Exhaust port; 22. Intake port;

[0036] 3. The first heat exchanger;

[0037] 4. Second heat exchanger; 41. Dry-bulb temperature sensor; 42. Wet-bulb temperature sensor;

[0038] 5. The first throttling device;

[0039] 6. Heating device. DETAILED DESCRIPTION

[0040] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] In the related art, the closed heat pump drying unit controls the start and stop of the compressor by the dry bulb temperature. Since the closed heat pump drying unit dehumidifies the airflow in the drying room during operation, when the drying material needs to be moisturized in the early stage of drying, the start of the compressor will cause the humidity in the drying room to be too low, affecting the drying quality of the drying material.

[0045] In order to solve the above technical problems, by obtaining the actual dry-bulb temperature and the actual wet-bulb temperature in the drying room, the start-up of the compressor is controlled according to the relationship between the difference between the actual dry-bulb temperature and the first dry-bulb set temperature and the first preset difference, as well as the relationship between the difference between the actual wet-bulb temperature and the first wet-bulb set temperature and the second preset difference, thereby avoiding starting the compressor when the humidity in the drying room is too low, and can improve the drying quality of the heat pump drying unit for drying materials that need to be moisturized in advance to a certain extent, which is beneficial to improving the applicability and reliability of the heat pump drying unit.

[0046] The heat pump drying unit according to the embodiment of the present application is described below.

[0047] See also Figure 1 , Figure 1 The heat pump drying unit 100 is a schematic structural diagram of a heat pump drying unit provided in an embodiment of the present application. The heat pump drying unit 100 comprises: a compressor 2, a first heat exchanger 3, a second heat exchanger 4, a dry-bulb temperature sensor 41, a wet-bulb temperature sensor 42 and a controller.

[0048] See also Figure 2 , Figure 2 A schematic diagram of a heat pump drying unit connected to a drying room provided in an embodiment of the present application. The circulating air duct 1 has an air outlet 11 and an air return port 12. The air outlet 11 and the air return port 12 are used to communicate with the drying room 200. Thus, the airflow in the circulating air duct 1 can flow from the air outlet 11 to the drying room 200, and then flow back from the drying room 200 to the circulating air duct 1 through the air return port 12.

[0049] In some embodiments, the heat pump drying unit 100 further includes a fan (not shown), which is used to drive the airflow from the return air port 12 to the air outlet 11. Thus, the fan can provide power for the airflow flowing from the return air port 12 to the air outlet 11, so that the airflow can circulate between the drying room 200 and the circulating air duct 1. Exemplarily, the fan is located in the circulating air duct 1. Another exemplary embodiment, the fan is located outside the circulating air duct 1 and is located at the air outlet 11, or at the return air port 12.

[0050] Please continue reading Figure 2 The compressor 2 has an air intake port 22 and an air discharge port 21. Specifically, the air intake port 22 of the compressor 2 is used for air intake, and the refrigerant enters the compression chamber of the compressor 2 through the air intake port 22 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 2 through the air discharge port 21 of the compressor 2. For example, the compressor 2 may be a scroll compressor, a rotor compressor, a screw compressor, or the like.

[0051] In some embodiments, there are multiple compressors 2. By providing multiple compressors 2, the drying efficiency of the heat pump drying unit 100 can be improved.

[0052] Please continue reading Figure 2 , the first heat exchanger 3 is located in the circulating air duct 1. Therefore, when the airflow flows through the first heat exchanger 3, the first heat exchanger 3 can exchange heat with the airflow.

[0053] One end of the first heat exchanger 3 is connected to the compressor 2 . Thus, the refrigerant flowing out of the compressor 2 can flow into the first heat exchanger 3 .

[0054] Please refer to Figure 2 , the second heat exchanger 4 is located in the circulating air duct 1. Therefore, when the airflow flows through the second heat exchanger 4, the second heat exchanger 4 can exchange heat with the airflow.

[0055] One end of the second heat exchanger 4 is connected to the other end of the first heat exchanger 3 through the first throttling device 5, and the other end of the second heat exchanger 4 is connected to the compressor 2. Therefore, the refrigerant flowing out of the first heat exchanger 3 can flow to the first throttling device 5, and the first throttling device 5 can throttle and reduce the pressure of the refrigerant flowing through, and the refrigerant after throttling and reducing the pressure can flow to the second heat exchanger 4, and the refrigerant exchanges heat in the second heat exchanger 4, and the refrigerant after heat exchange flows to the compressor 2.

[0056] Exemplarily, the first throttling device 5 may be a capillary tube, a throttling valve, an electronic expansion valve or a thermal expansion valve.

[0057] In some embodiments, the second heat exchanger 4 and the first heat exchanger 3 are arranged in sequence in the flow direction of the airflow in the circulating air duct 1. When the heat pump drying unit 100 is in operation, the first heat exchanger 3 is a condenser, the second heat exchanger 4 is an evaporator, and the airflow in the circulating air duct 1 can be heated when passing through the first heat exchanger 3, and can be cooled and dehumidified when passing through the second heat exchanger 4.

[0058] The working mode of the heat pump drying unit 100 according to the embodiment of the present application is described below.

[0059] See also Figure 3 , Figure 3 Schematic diagram of the operation mode of the heat pump drying unit 100 provided in the embodiment of the present application. When the heat pump drying unit 100 is in the operation mode, the controller controls the compressor 2 and the fan to start, and controls the first throttling device 5 to throttle. At this time, the first heat exchanger 3 is a condenser, and the second heat exchanger 4 is an evaporator.

[0060] Refrigerant flow direction: The high-temperature and high-pressure gaseous refrigerant discharged from the air intake port 22 of the compressor 2 flows into the first heat exchanger 3, and becomes a high-temperature and medium-pressure liquid refrigerant after sufficient heat exchange in the first heat exchanger 3. Then the refrigerant flowing out of the first heat exchanger 3 flows to the first throttling device 5, 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 5. The refrigerant flowing out of the first throttling device 5 flows to the second heat exchanger 4, and becomes a low-temperature and low-pressure gaseous refrigerant after heat exchange in the second heat exchanger 4. Finally, it flows back to the air intake port 22 of the compressor 2 from the second heat exchanger 4.

[0061] At this time, the airflow in the circulating air duct 1 first flows through the second heat exchanger 4 when it flows from the return air port 12 to the air outlet 11. The second heat exchanger 4 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 first heat exchanger 3, which condenses and releases heat to heat the airflow passing through.

[0062] See also Figure 3 , Figure 3 This is a schematic diagram of the structure of another heat pump drying unit provided in an embodiment of the present application. In some implementations, the heat pump drying unit 100 further includes a heating device 6, which can be a resistance wire, an electric heating wire, or the like.

[0063] See also Figure 4 , Figure 4 A schematic diagram of the structure of another heat pump drying unit provided in an embodiment of the present application. The heating device 6 is located in the circulating air duct 1 and between the first heat exchanger 3 and the air outlet 11. Thus, the airflow heated by the first heat exchanger 3 can be reheated by the heating device 6, avoiding the problem that the first heat exchanger 3 cannot be heated to the preset temperature, which is conducive to improving the reliability of the operation of the heat pump drying unit 100. At the same time, when there is no need to dehumidify the drying room 200, the heating device 6 can also be used to directly heat the airflow.

[0064] In some implementations, there are multiple heating devices 6. By providing multiple heating devices 6, the heating efficiency of the heat pump drying unit 100 on the airflow can be improved.

[0065] In some embodiments, the circulating air duct 1 has a fresh air inlet (not shown), which is connected to the outside atmosphere, and the first heat exchanger 3 is located on the air supply path from the fresh air inlet to the air outlet 11. Therefore, the outside atmosphere can enter the circulating air duct 1 through the fresh air inlet, and after heat exchange in the first heat exchanger 3, can flow into the drying room 200.

[0066] In some embodiments, a wind deflector (not shown) is rotatably provided at the fresh air inlet. This arrangement can control the size of the airflow entering the circulating air duct 1 from the fresh air inlet by controlling the rotation angle of the wind deflector.

[0067] In some embodiments, a dry bulb temperature sensor 41 and a wet bulb temperature sensor 42 may be connected to the controller. The dry bulb temperature sensor 41 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.

[0068] See also Figure 5 , Figure 5 A schematic diagram of another heat pump drying unit 100 provided in an embodiment of the present application. In some embodiments, the dry-bulb temperature sensor 41 and the wet-bulb temperature sensor 42 may be disposed on one side of the second heat exchanger 4 and located in the circulating air duct 1. Such an arrangement is conducive to improving the accuracy of the detection of the dry-bulb temperature sensor 41 and the wet-bulb temperature sensor 42.

[0069] In other embodiments, the dry-bulb temperature sensor 41 and the wet-bulb temperature sensor 42 may be disposed in the drying room 200, and the dry-bulb temperature sensor 41 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 41 and the wet-bulb temperature sensor 42.

[0070] 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 .

[0071] 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.

[0072] 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:

[0073] S1: Acquire the actual dry-bulb temperature and the actual wet-bulb temperature; acquire the actual dry-bulb temperature in the drying room 200 through the dry-bulb temperature sensor 41 , and acquire the actual wet-bulb temperature in the drying room 200 through the wet-bulb temperature sensor 42 .

[0074] S2: Determine whether compressor 2 is started according to the relationship between the difference △Td between the actual dry-bulb temperature and the first dry-bulb set temperature and the first preset difference, and the relationship between the difference △Tw between the actual wet-bulb temperature and the first wet-bulb set temperature and the second preset difference. Wherein, difference △Td = actual dry-bulb temperature - first dry-bulb set temperature, difference △Tw = actual wet-bulb temperature - first wet-bulb set temperature. When the actual dry-bulb temperature is greater than the first dry-bulb set temperature, difference △Td is a positive number; when the actual dry-bulb temperature is less than the first dry-bulb set temperature, difference △Td is a negative number. The difference △Tw between the actual wet-bulb temperature and the first wet-bulb set temperature is similar to difference △Td, and can be either positive or negative.

[0075] Therefore, by obtaining the actual dry-bulb temperature and the actual wet-bulb temperature in the drying room 200, the start-up of the compressor 2 is controlled according to the relationship between the difference between the actual dry-bulb temperature and the first dry-bulb set temperature and the first preset difference, as well as the relationship between the difference between the actual wet-bulb temperature and the first wet-bulb set temperature and the second preset difference, thereby avoiding starting the compressor 2 when the humidity in the drying room 200 is too low, and can improve the drying quality of the heat pump drying unit 100 for drying materials that require preliminary moisturizing to a certain extent, thereby helping to improve the applicability and reliability of the heat pump drying unit 100.

[0076] See also Figure 7 , Figure 7 This is a flow chart of a second control method of the heat pump drying unit 100 provided in an embodiment of the present application. The method includes:

[0077] S1: Get the actual dry bulb temperature and the actual wet bulb temperature;

[0078] S2: When the difference △Td between the actual dry-bulb temperature and the first dry-bulb setting temperature is less than or equal to the first preset difference, and the difference △Tw between the actual wet-bulb temperature and the first wet-bulb setting temperature is greater than the second preset difference, the compressor 2 is controlled to start. Therefore, when the difference △Td between the actual dry-bulb temperature and the first dry-bulb setting temperature is less than or equal to the first preset difference, it means that the dry-bulb temperature in the drying room 200 is relatively low at this time. When the difference △Tw between the actual wet-bulb temperature and the first wet-bulb setting temperature is greater than the second preset difference, it means that the humidity in the drying room 200 is relatively high at this time, then the compressor 2 of the heat pump drying unit 100 is controlled to start at this time, so as to avoid the heat pump drying unit 100 from continuing to dehumidify the drying room 200 when the humidity in the drying room 200 is relatively low, and to avoid the heat pump drying unit 100 from affecting the materials in the drying room 200, which is conducive to improving the drying reliability of the heat pump drying unit 100.

[0079] Please continue reading Figure 7In some embodiments, the actual dry-bulb temperature is obtained, and when it is determined that the difference ΔTd between the actual dry-bulb temperature and the first dry-bulb set temperature is greater than the first preset difference, the compressor 2 is controlled to stop.

[0080] See also Figure 8 , Figure 8 Flow chart of the third control method of the heat pump drying unit 100 provided in the embodiment of the present application. In some embodiments, when the difference △Td between the actual temperature of the several bulbs and the first dry bulb set temperature is less than or equal to the first preset difference, and the difference △Tw between the actual temperature of the wet bulb and the first wet bulb set temperature is less than or equal to the second preset difference, the heating device 6 is controlled to start, and the compressor 2 is stopped. Such a setting can prevent the heat pump drying unit 100 from continuing to dehumidify the drying room 200 when the humidity of the drying room 200 is low, and prevent the heat pump drying unit 100 from affecting the materials in the drying room 200, which is conducive to improving the reliability of the drying of the heat pump drying unit 100. In addition, by turning on the heating device 6, the temperature in the drying room 200 can be increased without dehumidifying the drying room 200, which is conducive to improving the drying quality of the heat pump drying unit 100 for the drying materials that need to be moisturized in the early stage, and thus is conducive to improving the applicability and reliability of the heat pump drying unit 100.

[0081] See also Fig. 9 , Fig. 9 This is a flow chart of a fourth control method of the heat pump drying unit 100 provided in an embodiment of the present application. The method includes:

[0082] S1: Get the actual dry bulb temperature and the actual wet bulb temperature;

[0083] S2: When the difference △Td between the actual dry-bulb temperature and the first dry-bulb set temperature is less than or equal to the first preset difference, and the difference △Tw between the actual wet-bulb temperature and the first wet-bulb set temperature is greater than the second preset difference, the compressor 2 is controlled to start. After the compressor 2 is started, it is determined whether the difference △Td between the actual dry-bulb temperature and the first dry-bulb set temperature is greater than the first preset difference. If the difference △Td between the first dry-bulb set temperature and the actual dry-bulb temperature is less than the first preset difference, the heating device 6 is controlled to start.

[0084] S3: After the compressor 2 is started, it is determined whether the difference ΔTd between the actual dry-bulb temperature and the first dry-bulb set temperature is greater than a first preset difference;

[0085] S4: If the difference ΔTd between the first dry-bulb set temperature and the actual dry-bulb temperature is less than the first preset difference, the heating device 6 is controlled to start.

[0086] Thus, it is possible to avoid the problem that after the heat pump drying unit 100 starts the compressor 2, the first heat exchanger 3 is always unable to heat the dry bulb temperature in the drying chamber 200 to the required temperature. By controlling the heating device 6 to start by the controller, the air in the circulation air duct 1 can be reheated after passing through the heating device 6, so that the temperature of the air flow flowing into the drying chamber 200 can meet the requirements, which is beneficial to improving the stability and reliability of the heat pump drying unit 100.

[0087] Please refer to Fig.10 , Fig.10 which is a flowchart of the number of compressors 2 started by the heat pump drying unit 100 provided in the embodiment of the present application.

[0088] S1: According to the first difference interval in which the difference △Td between the actual dry bulb temperature and the first set dry bulb temperature is located, determine the number n of compressors 2 corresponding to the first difference interval. The number n of compressors 2 corresponding to different first difference intervals and different first difference intervals are in a positive correlation relationship.

[0089] S2: According to the determined number n of compressors 2, control n compressors 2 to start.

[0090] Wherein, n is greater than or equal to 1.

[0091] Thus, by setting the number n of compressors 2 corresponding to the first difference interval, the heat pump drying unit 100 can determine the number of compressors 2 to be started according to the first difference interval in which the difference △Td between the actual dry bulb temperature and the first set dry bulb temperature is located, so that the heat pump drying unit 100 can control the number of compressors 2 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.

[0092] Please refer to Fig.11 , Fig.11 which is a relationship diagram between △Td and the number of compressors 2 started provided in the embodiment of the present application. Exemplarily, multiple first difference intervals can be respectively (0, a), [a, b), [b, c), [c, d), [d, e), where a < b < c < d < e. When the first difference interval is (0, a), the number of compressors 2 started can be 1; when the first difference interval is [a, b), the number of compressors 2 started can be 2; when the first difference interval is [b, c), the number of compressors 2 started can be 3; when the first difference interval is [c, d), the number of compressors 2 started can be 4. For example, when it is determined that the first difference interval in which the difference △Td between the actual dry bulb temperature and the first set dry bulb temperature is located is [a, b), and the obtained number of compressors 2 started corresponding to it can be 2, then control 2 compressors 2 to start.

[0093] Please refer to Fig.12 , Fig.12 Flow chart of the rotation angle of the fresh air door of the heat pump drying unit 100 provided by the embodiment of the present application.

[0094] S1: According to the second difference interval where the difference △Tw between the actual wet-bulb temperature and the second set wet-bulb temperature is located, determine the opening angle α of the air deflector corresponding to the second difference interval. The opening angle α of the air deflector corresponding to different second difference intervals has a positive correlation with different second difference intervals.

[0095] S2: Control the air deflector to rotate to the opening angle α according to the determined opening angle of the air deflector.

[0096] Among them, the value range of the opening angle is 0 - 90°, and the second set wet-bulb temperature is less than the first set wet-bulb temperature.

[0097] Thus, by setting the opening angle of the air deflector corresponding to the second difference interval, the heat pump drying unit 100 can determine the opening angle α of the air deflector corresponding to the second difference interval according to the second difference interval where the difference △Tw between the actual wet-bulb temperature and the second set wet-bulb temperature is located, 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.

[0098] Please refer to Fig.13 , Fig.13 Relationship diagram of △Tw and the opening angle of the air deflector provided by the embodiment of the present application. Exemplarily, multiple second difference intervals can be respectively (0, a), [a, b), [b, c), [c, d), [d, e), where a < b < c < d < e. When the second difference interval is (0, a), the opening angle of the air deflector can be 15°; when the second difference interval is [a, b), the opening angle of the air deflector can be 45°; when the second difference interval is [b, c), the opening angle of the air deflector can be 60°; when the second difference interval is [c, d), the opening angle of the air deflector can be 75°. For example, when it is determined that the second difference interval where the difference △Tw between the actual wet-bulb temperature and the second set 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°.

[0099] Please refer to Fig.14 , Fig.14 Flow chart of the number of heating devices 6 started by the heat pump drying unit 100 provided by the embodiment of the present application.

[0100] S1: Determine the number z of the heating devices 6 corresponding to the second difference range according to the second difference range in which the difference △Td between the actual dry-bulb temperature and the first set dry-bulb temperature is located. The number z of the heating devices 6 corresponding to different second difference ranges is positively correlated with different second difference ranges.

[0101] S2: Control z heating devices 6 to start according to the determined number z of the heating devices 6.

[0102] Wherein, z is greater than or equal to 1.

[0103] Thus, by setting the number z of the heating devices 6 corresponding to the second difference range, the heat pump drying unit 100 can determine the number of the heating devices 6 to be started according to the second difference range in which the difference △Td between the actual dry-bulb temperature and the first set dry-bulb temperature is located, so that the heat pump drying unit 100 can control the number of the heating devices 6 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.

[0104] Please refer to Fig.15 , Fig.15 , which is a relationship diagram of △Td and the number of the heating devices 6 started 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 number of the heating devices 6 started can be 1; when the second difference range is [a, b), the number of the heating devices 6 started can be 2; when the second difference range is [b, c), the number of the heating devices 6 started can be 3; when the second difference range is [c, d), the number of the heating devices 6 started can be 4. For example, when it is determined that the second difference range in which the difference △Td between the actual dry-bulb temperature and the first set dry-bulb temperature is located is [a, b), and the obtained number of the heating devices 6 started corresponding thereto is 2, then control 2 heating devices 6 to start.

[0105] In some embodiments, the value range of the first preset difference is (0, 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 or 2 °C, etc. By setting the value range of the first preset difference, it is beneficial to improve the reliability of the heat pump drying unit 100.

[0106] In some embodiments, the value range of the second preset difference is [-2, 0) ° 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 or -2 ° C. By setting the value range of the second preset difference, it is beneficial to improve the reliability of the heat pump drying unit 100.

[0107] 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.

[0108] 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.

[0109] In some embodiments, the value range of the third difference interval is (-∞, -0.5]°C. By setting the value range of the third difference interval, it is helpful to improve the reliability of the heat pump drying unit 100.

[0110] 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.

[0111] 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-core (single-CPU) processor or a multi-core (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).

[0112] 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 (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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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 circulating air duct, wherein the circulating air duct has an air outlet and an air return outlet, and the air outlet and the air return outlet are used to communicate with the drying room; The 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; Multiple compressors; A first heat exchanger, wherein the first heat exchanger is located in the circulating air duct, and one end of the first heat exchanger is connected to the compressor; the first heat exchanger is located on an air supply path from the fresh air inlet to the air outlet; A second heat exchanger, wherein the second heat exchanger is located in the circulating air duct, one end of the second heat exchanger is connected to the other end of the first heat exchanger through a first throttling device, and the other end of the second heat exchanger is connected to the compressor; 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; A heating device, located in the circulating air duct and between the first heat exchanger and the air outlet; The controller is configured as: Get the actual dry bulb temperature and the actual wet bulb temperature; When the difference △Td between the actual dry-bulb temperature and the first dry-bulb set temperature is less than or equal to the first preset difference, and the difference △Tw between the actual wet-bulb temperature and the first wet-bulb set temperature is greater than the second preset difference, the compressor is controlled to start; If the difference ΔTd between the actual dry-bulb temperature and the first dry-bulb set temperature is less than or equal to the first preset difference, and the difference ΔTw between the actual wet-bulb temperature and the first wet-bulb set temperature is less than or equal to the second preset difference, the heating device is controlled to start and the compressor is stopped; According to the first difference interval in which the difference ΔTd between the actual dry-bulb temperature and the first dry-bulb set temperature is located, the number n of the compressors corresponding to the first 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; According to the second difference interval in which the difference △Tw between the actual wet-bulb temperature and the second wet-bulb set temperature is located, determining the opening angle of the air guide plate corresponding to the second 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; The value range of the opening angle is 0-90°, and the second wet-bulb set temperature is lower than the first wet-bulb set temperature.

2. The heat pump drying unit according to claim 1, characterized in that: The controller is configured to: After the compressor is started, determining whether a difference ΔTd between the actual dry-bulb temperature and the first dry-bulb set temperature is greater than a first preset difference; If the difference ΔTd between the first dry-bulb set temperature and the actual dry-bulb temperature is less than a first preset difference, the heating device is controlled to start.

3. The heat pump drying unit according to claim 1, characterized in that: There are multiple heating devices; The controller is configured to: According to the third difference interval in which the difference △Td between the actual dry-bulb temperature and the second set dry-bulb temperature is located, the number z of the heating devices corresponding to the third difference interval is determined, and the number z of the heating devices corresponding to different third difference intervals is positively correlated with different third difference intervals; According to the determined number z of the heating devices, controlling z of the heating devices to turn on; Wherein, z is greater than or equal to 1, and the second dry-bulb set temperature is greater than the first dry-bulb set temperature.

4. The heat pump drying unit according to claim 1, characterized in that: The value range of the first preset difference is (0, 2]°C.

5. The heat pump drying unit according to claim 1, characterized in that: The value range of the second preset difference is [-2, 0)°C.

6. A control method for a heat pump drying unit, characterized in that: The heat pump drying unit comprises: A circulating air duct, wherein the circulating air duct has an air outlet and an air return outlet, wherein the air outlet and the air return outlet are used to communicate with the drying room; the circulating air duct has a fresh air inlet, wherein the fresh air inlet is communicated with the outside atmosphere; an air guide plate is rotatably provided at the fresh air inlet; Multiple compressors; A first heat exchanger, wherein the first heat exchanger is located in the circulating air duct, and one end of the first heat exchanger is connected to the compressor; the first heat exchanger is located on an air supply path from the fresh air inlet to the air outlet; A second heat exchanger, wherein the second heat exchanger is located in the circulating air duct, one end of the second heat exchanger is connected to the other end of the first heat exchanger through a first throttling device, and the other end of the second heat exchanger is connected to the compressor; 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; A heating device, located in the circulating air duct and between the first heat exchanger and the air outlet; The method comprises: Get the actual dry bulb temperature and the actual wet bulb temperature; When the difference △Td between the actual dry-bulb temperature and the first dry-bulb set temperature is less than or equal to the first preset difference, and the difference △Tw between the actual wet-bulb temperature and the first wet-bulb set temperature is greater than the second preset difference, the compressor is controlled to start; If the difference ΔTd between the actual dry-bulb temperature and the first dry-bulb set temperature is less than or equal to the first preset difference, and the difference ΔTw between the actual wet-bulb temperature and the first wet-bulb set temperature is less than or equal to the second preset difference, the heating device is controlled to start and the compressor is stopped; According to the first difference interval in which the difference ΔTd between the actual dry-bulb temperature and the first dry-bulb set temperature is located, the number n of the compressors corresponding to the first 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; According to the second difference interval in which the difference △Tw between the actual wet-bulb temperature and the second wet-bulb set temperature is located, determining the opening angle of the air guide plate corresponding to the second 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; The value range of the opening angle is 0-90°, and the second wet-bulb set temperature is lower than the first wet-bulb set temperature.

Images