Heat pump dryer, dehumidification control method, and drying room

Abstract

The present application relates to the technical field of drying, and provides a heat pump dryer, a dehumidification control method and a drying room. The heat pump dryer comprises a casing, a circulating heating unit and a first air valve. The casing is provided with an air return port and an air exhaust port. The circulating heating unit is arranged in the casing and comprises a compressor, an inner evaporator and a condenser connected in series. The condenser is located at the air exhaust port. The inner evaporator is connected in parallel with an outer evaporator, and the outer evaporator is located outside the casing. The casing is provided with a first chamber in which the inner evaporator is located and a second chamber in which the condenser is located. The first chamber is connected with the second chamber. The first chamber is connected with the air return port, and the second chamber is connected with the air exhaust port. The first air valve is arranged between the first chamber and the outer evaporator in an openable and closable manner. The present application can discharge the internal hot air to the outer evaporator through the first air valve, and the outer evaporator can absorb the heat of the discharged air, so as to achieve the purposes of heat energy recovery and power saving.

Description

Technical Field

[0001] This invention relates to the field of drying technology, and in particular to a heat pump dryer, a dehumidification control method, and a drying room. Background Technology

[0002] Heat pump dryers are generally used in drying rooms. They dry the materials in the drying room by dehumidifying them.

[0003] In related technologies, when a heat pump dryer is performing dehumidification, if the dry-bulb temperature of the drying chamber exceeds the target dry-bulb temperature and the internal dehumidification cannot meet the dehumidification requirements, the dehumidification method mainly adopted is to use the compressor to discharge the excess high-temperature hot air inside to the outside. However, this wastes heat energy and occupies the compressor's working time, resulting in high power consumption and energy waste. Summary of the Invention

[0004] This invention provides a heat pump dryer, a dehumidification control method, and a drying room. By using a first air valve to discharge internal hot air to an external evaporator, the external evaporator absorbs the heat of the discharged air, thereby achieving the purpose of heat energy recovery and saving electricity.

[0005] This invention provides a heat pump dryer, comprising:

[0006] The casing is equipped with a return air vent and an exhaust air vent;

[0007] A circulating heating unit, disposed within the casing, includes: a compressor, an internal evaporator, and a condenser connected together, the condenser being located at the exhaust port; and an external evaporator connected in parallel to the internal evaporator, the external evaporator being located outside the casing;

[0008] The casing contains a first chamber where the internal evaporator is located and a second chamber where the condenser is located. The first chamber is connected to the second chamber, the first chamber is connected to the return air vent, and the second chamber is connected to the exhaust air vent.

[0009] A first air valve is closable and disposed between the first chamber and the external evaporator to control the heat exchange between the air in the first chamber and the external evaporator.

[0010] According to a heat pump dryer provided by the present invention, a heat exchanger and a second air valve are further provided inside the casing. A first flow channel is formed between the heat exchanger, the casing, and the second air valve. A second flow channel is formed between the heat exchanger, the casing, and the inner evaporator. The first air valve is disposed on the side wall of the second flow channel near the outer evaporator. A third flow channel is formed between the heat exchanger, the inner evaporator, and the casing. A second chamber is formed between the second air valve, the heat exchanger, the casing, and the condenser. The second air valve is closable between the first flow channel and the second chamber to control the connection and disconnection of the return air inlet with the first flow channel and the second chamber.

[0011] The first chamber includes: the first flow channel, the second flow channel, and the third flow channel.

[0012] According to a heat pump dryer provided by the present invention, a third air valve is further included, wherein the third air valve is closable and disposed in the third flow channel for controlling the heat exchange between the air in the third flow channel and the outside.

[0013] According to a heat pump dryer provided by the present invention, a fourth air valve is further included, which is closable in the second chamber and is used to control the heat exchange between the air in the second chamber and the outside.

[0014] A heat pump dryer according to the present invention further includes:

[0015] A first temperature sensor is installed in the drying chamber to detect the dry-bulb temperature of the drying chamber.

[0016] A second temperature sensor is installed in the drying chamber to detect the wet-bulb temperature of the drying chamber.

[0017] The controller is electrically connected to the compressor, the first air valve, the second air valve, the third air valve, the fourth air valve, the first temperature sensor, and the second temperature sensor, respectively.

[0018] A heat pump dryer according to the present invention further includes:

[0019] The third temperature sensor, electrically connected to the controller, is used to detect the ambient temperature.

[0020] A fourth temperature sensor is disposed in the third flow channel and electrically connected to the controller, and is used to detect the temperature in the third flow channel.

[0021] According to a heat pump dryer provided by the present invention, the first chamber and / or the second chamber are respectively provided with fans.

[0022] The present invention also provides a dehumidification control method for the above-mentioned heat pump dryer, comprising:

[0023] Obtain the dry bulb temperature and wet bulb temperature of the drying chamber;

[0024] In response to the fact that the difference between the dry-bulb temperature of the drying chamber and the target dry-bulb temperature is greater than or equal to a first preset value, and the difference between the target wet-bulb temperature and the wet-bulb temperature of the drying chamber is less than or equal to a second preset value, the first air valve is controlled to open.

[0025] According to the dehumidification control method of a heat pump dryer provided by the present invention, the step of controlling the opening of the first air valve specifically includes: adjusting the opening degree of the first air valve according to the difference between the dry bulb temperature of the drying chamber and the target dry bulb temperature.

[0026] The present invention also provides a dehumidification control method for the above-mentioned heat pump dryer, comprising:

[0027] Obtain the dry-bulb temperature of the drying room;

[0028] The opening of the second air valve is adjusted based on the dry bulb temperature of the drying chamber to control the ratio of air volume entering the first flow channel and the second chamber through the return air inlet.

[0029] A dehumidification control method for a heat pump dryer according to the present invention further includes the following steps:

[0030] Obtain the wet-bulb temperature of the drying chamber;

[0031] In response to the fact that the difference between the dry-bulb temperature of the drying chamber and the target dry-bulb temperature is greater than or equal to a first preset value, and the difference between the target wet-bulb temperature and the wet-bulb temperature of the drying chamber is less than or equal to a second preset value, the first air valve and the third air valve are controlled to open.

[0032] According to the dehumidification control method of a heat pump dryer provided by the present invention, the step of controlling the opening of the first air valve and the third air valve specifically includes: adjusting the opening degree of the first air valve and the third air valve according to the difference between the dry bulb temperature of the drying chamber and the target dry bulb temperature.

[0033] A dehumidification control method for a heat pump dryer according to the present invention further includes the following steps:

[0034] The wet-bulb temperature of the drying chamber, the ambient temperature, and the temperature inside the third flow channel are obtained.

[0035] In response to the fact that the difference between the target dry-bulb temperature and the dry-bulb temperature of the drying chamber is greater than or equal to a third preset value, the difference between the ambient temperature and the temperature in the third flow channel is greater than or equal to a fourth preset value, and the difference between the target wet-bulb temperature and the wet-bulb temperature of the drying chamber is less than or equal to a second preset value, the third air valve and the fourth air valve are controlled to open.

[0036] According to the dehumidification control method of a heat pump dryer provided by the present invention, the step of controlling the opening of the third air valve and the fourth air valve specifically includes: adjusting the opening degree of the third air valve and the fourth air valve according to the difference between the target dry-bulb temperature and the dry-bulb temperature of the drying chamber.

[0037] The present invention also provides a drying room, comprising: the above-described heat pump dryer, or, when performing dehumidification, employing the above-described dehumidification control method of the heat pump dryer.

[0038] The heat pump dryer, dehumidification control method, and drying chamber provided by this invention have a first chamber containing an internal evaporator and a second chamber containing a condenser within the casing. The first and second chambers are connected, with the first chamber connected to a return air vent and the second chamber connected to an exhaust air vent. External air to be dehumidified can enter the first chamber through the return air vent, flow through the internal evaporator to absorb heat, achieving condensation and dehumidification, and then enter the second chamber, flow through the condenser for heating, before being discharged from the exhaust air vent. A first air valve is closable between the first chamber and the external evaporator. When the dry-bulb temperature of the drying chamber exceeds the target dry-bulb temperature, the air in the first chamber can be controlled to be discharged to exchange heat with the external evaporator, thereby achieving heat energy recovery and improving the heat exchange effect of the circulating heating unit, while reducing power consumption. Therefore, this invention, by employing a first air valve, can discharge internal hot air to the external evaporator, where the external evaporator absorbs the heat of the discharged air, achieving heat energy recovery and saving power. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in this invention or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the low-temperature closed-loop dehumidification mode of the heat pump dryer provided by the present invention;

[0041] Figure 2 This is a schematic diagram of the high-temperature open-loop mode of the heat pump dryer provided by the present invention;

[0042] Figure 3This is a schematic diagram of the heating mode of the heat pump dryer provided by the present invention;

[0043] Figure 4 This is one of the flowcharts illustrating the dehumidification control method for the heat pump dryer provided by the present invention;

[0044] Figure 5 This is the second schematic flowchart of the dehumidification control method for the heat pump dryer provided by the present invention;

[0045] Figure 6 This is the third flowchart illustrating the dehumidification control method for the heat pump dryer provided by the present invention;

[0046] Figure 7 This is the fourth flowchart illustrating the dehumidification control method for the heat pump dryer provided by this invention.

[0047] Figure label:

[0048] 1: Housing; 101: Return air vent;

[0049] 2: First air valve; 3: Internal evaporator; 4: Condenser; 5: External evaporator;

[0050] 6: First chamber; 601: First flow channel; 602: Second flow channel; 603: Third flow channel;

[0051] 7: Second chamber; 8: Heat exchanger; 9: Second air valve; 10: First partition;

[0052] 11: Second partition; 12: Third air valve; 13: Fourth air valve. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0054] In the description of the embodiments of the present invention, it should be noted that the terms "middle," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0055] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0056] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0057] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0058] The following is combined Figures 1-7 The present invention describes a heat pump dryer, a dehumidification control method, and a drying room.

[0059] According to an embodiment of the first aspect of the present invention, referring to Figures 1-3 As shown, the heat pump dryer provided by the present invention mainly includes: a casing 1, a circulating heating unit and a first air valve 2.

[0060] The casing 1 is equipped with a return air inlet 101 and an exhaust air outlet. The air outside the casing 1 that needs to be dehumidified can enter the casing 1 through the return air inlet 101. The air outside the casing 1 that needs to be dehumidified includes, but is not limited to, the high-humidity air generated after drying materials in the drying room. The high-temperature air that has been dehumidified and dried by the circulating heating unit of the dryer can be discharged through the exhaust air outlet and sent back into the drying room to dry materials again, thus realizing circulation.

[0061] The circulating heating unit is housed within the casing 1 and includes a compressor, an internal evaporator 3, and a condenser 4 connected together. The condenser 4 is located at the exhaust vent. An external evaporator 5 is connected in parallel to the internal evaporator 3 and is located outside the casing 1. During heating, the high-temperature, high-pressure refrigerant gas generated by the compressor enters the condenser 4 to release heat, forming a liquid refrigerant. This liquid then enters both the internal and external evaporators 3 and 5. The internal evaporator 3 absorbs heat from the air inside the casing 1, causing the refrigerant to turn into a gas before being compressed by the compressor. Simultaneously, when the first air valve 2 opens, the hot air inside the casing 1 is exhausted to the external evaporator 5, which absorbs the heat from the exhausted air, achieving heat recovery and reducing the power consumption of the circulating heating unit, thus improving the heating effect.

[0062] Understandably, when the condenser 4 condenses and releases heat, it can further heat the air at the exhaust vent, increasing the temperature of the exhaust air and thus improving the drying effect; and when the internal evaporator 3 evaporates and absorbs heat, it can cool the water vapor in the air, bringing it to the dew point temperature, thus achieving the condensation dehumidification effect.

[0063] The casing 1 has a first chamber 6 containing the inner evaporator 3 and a second chamber 7 containing the condenser 4. The first chamber 6 is connected to the second chamber 7. The first chamber 6 is connected to the return air vent 101, and the second chamber 7 is connected to the exhaust vent. The first air valve 2 is closable between the first chamber 6 and the outer evaporator 5 and is used to control the heat exchange between the air in the first chamber 6 and the outer evaporator 5.

[0064] During operation, the external air to be dehumidified enters the first chamber 6 through the return air inlet 101, flows through the inner evaporator 3 to absorb heat, and achieves condensation dehumidification. Then it enters the second chamber 7, flows through the condenser 4 for heating, and is then discharged from the exhaust outlet. When the temperature inside the drying room is high, the first air valve 2 can be opened to discharge excess heat to the outer evaporator 5. The outer evaporator 5 absorbs the heat from the exhaust air, achieving heat recovery and reducing the power consumption of the circulating heating unit, thereby improving the heating effect.

[0065] The heat pump dryer of this invention can control the heat exchange between the air in the first chamber 6 and the external evaporator 5, thereby achieving heat energy recovery and improving the heat exchange effect of the circulating heating unit while reducing power consumption. Therefore, this invention can discharge internal hot air to the external evaporator 5 via the first air valve 2, and the external evaporator 5 absorbs the heat from the discharged air, achieving the purposes of heat energy recovery and power saving.

[0066] Currently, during the drying process, as the temperature in the drying room rises, the relative humidity decreases. As a result, under high temperature and low humidity conditions, the condensation temperature of water vapor in the drying room cannot reach the dew point temperature, leading to poor condensation and ineffective dehumidification.

[0067] To solve the above technical problems, refer to Figures 1-3 As shown, in this embodiment of the invention, the casing 1 is further provided with a heat exchanger 8 and a second air valve 9. A first flow channel 601 is formed between the heat exchanger 8 and the casing 1 and the second air valve 9. A second flow channel 602 is formed between the heat exchanger 8 and the casing 1 and the inner evaporator 3. The first air valve 2 is disposed on the side wall of the second flow channel 602 near the outer evaporator 5, and a third flow channel 603 is formed between the heat exchanger 8, the inner evaporator 3 and the casing 1. A second chamber 7 is formed between the second air valve 9 and the heat exchanger 8, the casing 1 and the condenser 4. The second air valve 9 is closably disposed between the first flow channel 601 and the second chamber 7 to control the opening and closing of the return air vent 101 with the first flow channel 601 and the second chamber 7. The first chamber 6 includes the first flow channel 601, the second flow channel 602 and the third flow channel 603.

[0068] It is understandable that by adjusting the opening of the second air valve 9, the ratio of air volume entering the first flow channel 601 through the return air inlet 101 to that entering the second chamber 7 can be controlled.

[0069] Specifically, the dry-bulb temperature of the drying chamber is compared with the target dry-bulb temperature. When the dry-bulb temperature of the drying chamber is lower than the target dry-bulb temperature, the second air valve 9 is closed. At this time, all the air entering through the return air vent 101 undergoes initial heat exchange with the heat exchanger 8 via the first flow channel 601, achieving pre-cooling and temperature reduction. Then, it flows through the second flow channel 602 to exchange heat with the internal evaporator 3, which helps improve the condensation effect and achieve low-temperature dehumidification. Figure 1 As shown.

[0070] As the temperature inside the drying chamber gradually rises, when the dry-bulb temperature of the drying chamber is greater than or equal to the target dry-bulb temperature, the second air valve 9 is gradually opened. At this time, a portion of the air entering through the return air vent 101 undergoes a first heat exchange with the heat exchanger 8 through the first flow channel 601, achieving pre-cooling and temperature reduction. Then, after heat exchange with the inner evaporator 3 through the second flow channel 602, it achieves condensation and dehumidification. Next, it undergoes a second heat exchange with the heat exchanger 8 through the third flow channel 603, achieving preheating and temperature increase. Finally, it flows through the second chamber 7 and exchanges heat with the condenser 4. Simultaneously, another portion of the air entering through the return air vent 101 directly exchanges heat with the condenser 4 through the second chamber 7 and returns to the drying chamber, achieving high-temperature dehumidification. Furthermore, during this process, the first air valve 2 can be opened to discharge excess heat, which is then absorbed by the external evaporator 5, achieving heat recovery. Figure 2 As shown.

[0071] It should be noted that in this high-temperature dehumidification process, by reducing the dehumidification air volume that exchanges heat with the internal evaporator 3, i.e. the water vapor flow rate, the water vapor in the air can reach the dew point temperature better and achieve condensation.

[0072] Furthermore, as the temperature in the drying chamber increases and the relative humidity decreases, the opening degree of the second air valve 9 increases, until the second air valve 9 tends to... Figure 3 As shown in the fully open state, this design can further reduce the dehumidification air volume, allowing water vapor to better reach the dew point temperature and effectively improve the condensation effect.

[0073] In this embodiment of the invention, the ratio of airflow entering the first chamber 6 and the second chamber 7 via the return air inlet 101 is controlled by the second air valve 9, enabling precise adjustment of the condensation effect and achieving internal dehumidification across the entire drying temperature range. Furthermore, especially during high-temperature dehumidification, reducing the flow rate of water vapor exchanging heat with the internal evaporator 3 achieves effective condensation, thereby improving the high-temperature dehumidification condensation effect. Therefore, this invention improves the internal dehumidification condensation effect at high temperatures in the drying chamber, avoiding unnecessary work by the compressor during condensation and preventing the water vapor condensation temperature from reaching the dew point, thus saving energy.

[0074] The specific type of heat exchanger 8 in this invention is not particularly limited. For example, heat exchanger 8 can be an aluminum foil heat exchanger.

[0075] According to one embodiment of the present invention, referring to Figure 1 As shown, the second air valve 9 is an electric valve plate. One end of the electric valve plate is rotatably connected to the heat exchanger 8. When the electric valve plate is in the closed state, it blocks the air from the return air port 101 from entering the second chamber 7, and allows all the air from the return air port 101 to enter the first chamber 6. (Refer to...) Figure 2 As shown, when the electric valve plate is in the open state, it guides the airflow through the return air vent 101, allowing the air to enter the first chamber 6 and the second chamber 7 respectively; (Refer to...) Figure 3 As shown, when the electric valve plate is in the fully open state, the electric valve plate is suitable for blocking the air in the return air vent 101 to prevent it from flowing into the first chamber 6. Through the guidance of the electric valve plate, all the air in the return air vent 101 enters the second chamber 7.

[0076] Therefore, the electric valve plate in this embodiment of the invention can, on the one hand, adjust the air volume ratio, and on the other hand, guide the airflow.

[0077] According to one embodiment of the present invention, the opening degree of the electric valve plate is between 0° and 90°, that is, the rotation angle of the electric valve plate is 90°. Specifically, when the electric valve plate is in the closed state, the electric valve plate is generally horizontally arranged, the return air port 101 is connected to the first flow channel 601 and disconnected from the second chamber 7; when the electric valve plate is in the open state, the electric valve plate is generally inclined, the return air port 101 is connected to the first flow channel 601 and the second chamber 7 respectively; when the electric valve plate is in the fully open state, the electric valve plate is generally vertically arranged, the return air port 101 is disconnected from the first flow channel 601 and connected to the second chamber 7, the electric valve plate blocks the air in the return air port 101, so that all of it enters the second chamber 7, that is, the connection and disconnection between the return air port 101 and the first flow channel 601 and the second chamber 7 can be controlled by controlling the opening and closing of the electric valve plate.

[0078] According to one embodiment of the present invention, the housing 1 includes: a first partition 10 and a second partition 11, the first partition 10 being disposed between a first flow channel 601 and a third flow channel 603, and the second partition 11 being disposed between a second flow channel 602 and a second chamber 7.

[0079] According to one embodiment of the present invention, the return air vent 101 is located on the lower right side of the casing 1, and the exhaust vent is located on the top of the casing 1; the compressor is located inside the casing 1, the internal evaporator 3 is located on the left side inside the casing 1, the condenser 4 is located on the top of the casing 1, and the heat exchanger 8 is located in the middle of the casing 1; the electric valve plate is rotatably located on the right side of the heat exchanger 8 inside the casing 1, and adjacent to the return air vent 101.

[0080] According to one embodiment of the present invention, referring to Figures 1-3 As shown, the heat pump dryer also includes a third air valve 12, which is openable and closable in the third flow channel 603 and is used to control the heat exchange between the air in the third flow channel 603 and the outside.

[0081] Furthermore, the heat pump dryer also includes a fourth air valve 13, which is closable in the second chamber 7 and used to control the heat exchange between the air in the second chamber 7 and the outside.

[0082] The types of the first air valve 2, the third air valve 12 and the fourth air valve 13 of the present invention are not particularly limited and can be designed according to actual working conditions. For example, the first air valve 2 can also be set as an electric valve plate.

[0083] According to one embodiment of the present invention, the heat pump dryer further includes: a first temperature sensor, a second temperature sensor, and a controller. The first temperature sensor is disposed in the drying chamber and is used to detect the dry-bulb temperature of the drying chamber; the second temperature sensor is disposed in the drying chamber and is used to detect the wet-bulb temperature of the drying chamber to determine whether to enter dehumidification mode; the controller is electrically connected to the compressor, the first air valve 2, the second air valve 9, the third air valve 12, the fourth air valve 13, the first temperature sensor, and the second temperature sensor, respectively, and is used to control the operation of the entire machine.

[0084] According to one embodiment of the present invention, the heat pump dryer further includes: a third temperature sensor and a fourth temperature sensor. The third temperature sensor can be disposed outside the housing 1 and electrically connected to the controller for detecting the ambient temperature. The fourth temperature sensor is disposed inside the third flow channel 603 and electrically connected to the controller for detecting the temperature inside the third flow channel 603.

[0085] Specifically, when the difference between the target dry-bulb temperature and the dry-bulb temperature of the drying chamber is greater than or equal to the third preset value (i.e., the drying chamber is at a lower temperature), the difference between the ambient temperature and the temperature inside the third flow channel 603 is greater than or equal to the fourth preset value (i.e., the ambient temperature is higher than the internal temperature), and the difference between the target wet-bulb temperature and the wet-bulb temperature of the drying chamber is less than or equal to the second preset value (i.e., the chamber is in dehumidification mode), the third air valve 12 and the fourth air valve 13 can be opened after the above conditions are met.

[0086] In this process, since the air temperature is relatively low after absorbing heat in the internal evaporator 3, opening the third air valve 12 allows for heat exchange with the relatively warmer outside air, absorbing heat from the outside air to achieve a first-stage temperature increase. The air then flows through the heat exchanger 8 for a second-stage temperature increase, and then through the second chamber 7. Opening the fourth air valve 13 allows for further absorption of heat from the outside air, achieving a third-stage temperature increase. Finally, the air passes through the condenser 4 for a fourth-stage temperature increase. Therefore, this embodiment of the invention, by setting the third air valve 12 and the fourth air valve 13, can achieve multi-stage temperature increases, effectively raising the temperature of the exhaust air and thus increasing the temperature of the drying chamber, thereby achieving energy savings.

[0087] According to one embodiment of the present invention, the first chamber 6 and / or the second chamber 7 are respectively provided with fans to increase the air flow speed, thereby improving the drying efficiency.

[0088] The working principle of the heat pump dryer provided by the present invention is described below, which generally includes: low-temperature closed-loop dehumidification mode, high-temperature open-loop dehumidification mode and heating mode.

[0089] Low-temperature closed-loop dehumidification mode: such as Figure 1As shown, when the temperature inside the drying chamber is low and the outside temperature is high, dehumidification is performed. The first air valve 2 and the second air valve 9 are closed, while the third air valve 12 and the fourth air valve 13 are open. At this time, the high-humidity air generated by the dried materials in the drying chamber enters the first flow channel 601 through the return air inlet 101 of the casing 1 and undergoes the first heat exchange with the heat exchanger 8 to achieve pre-cooling and lower the air temperature. At this time, the air temperature is close to the dew point temperature. Then, it flows through the second flow channel 602 and exchanges heat with the inner evaporator 3. The inner evaporator 3 absorbs heat and further lowers the air temperature to make it reach the dew point temperature, achieving condensation. The water generated after condensation is discharged, achieving the dehumidification function and obtaining low-temperature and low-humidity air. The low-temperature and low-humidity air flows through the third flow channel 603 and exchanges heat with the outside air, absorbing heat from the outside air and raising the temperature. Then, it undergoes the second heat exchange with the heat exchanger 8, raising the temperature again. Then, it flows through the second chamber 7 and exchanges heat with the condenser 4 to further raise the temperature. Finally, it is sent to the drying chamber to dry the materials through the exhaust port. This cycle repeats, thus achieving the goal of low-temperature closed-loop dehumidification.

[0090] High-temperature open-loop dehumidification mode: such as Figure 2 As shown, when the temperature inside the drying chamber is high and dehumidification is being performed, the first air valve 2, the second air valve 9, and the third air valve 12 are in the open state, while the fourth air valve 13 is in the closed state. At this time, a portion of the high-humidity air generated by the dried materials in the drying chamber enters the first flow channel 601 and pre-cools with the heat exchanger 8, lowering the air temperature to near the dew point temperature. Then, it enters the second flow channel 602, where excess hot air is discharged through the first air valve 2, further lowering the temperature. The discharged heat is absorbed by the external evaporator 5, and the internal air then exchanges heat with the internal evaporator 3. The internal evaporator 3 absorbs heat, further lowering the temperature until it fully reaches the dew point temperature, thus achieving cooling. The air condenses and discharges the water produced after condensation, thus achieving dehumidification. Opening the third air valve 12 in the third flow channel 603 lowers the temperature, which helps improve the condensation and dehumidification effect, resulting in low-temperature, low-humidity air. This air then exchanges heat with the heat exchanger 8 to raise the temperature. The air then flows into the second chamber 7 and mixes with another portion of the air directly entering the second chamber 7 from the dried materials in the drying room. It then exchanges heat with the condenser 4 again, further increasing the temperature, and is then sent to the drying room to dry the materials through the exhaust vent. Furthermore, in this high-temperature dehumidification mode, as the drying room temperature rises, the relative humidity decreases. During dehumidification, the second air valve 9 opens wider, meaning it is more inclined to... Figure 3 As shown in the diagram, the fully open position can further reduce the amount of dehumidifying air exchanged with the internal evaporator 3, thereby improving the condensation effect and achieving the purpose of high-temperature open-loop dehumidification.

[0091] Heating mode: such as Figure 3As shown, the first air valve 2 and the third air valve 12 can be opened or closed, the fourth air valve 13 is closed, and the second air valve 9 is fully open. In this mode, unlike the high-temperature dehumidification mode described above, the high-humidity air generated by the dried materials in the drying chamber enters the second chamber 7 and directly exchanges heat with the condenser 4 before flowing back into the drying chamber. At this time, the dehumidification airflow reaches its minimum. It can be understood that in this mode, since the air primarily passes through the condenser 4 and does not undergo condensation and dehumidification through the internal evaporator 3, this mode can be set as a heating mode.

[0092] Therefore, the heat pump dryer in this embodiment of the invention is an integrated on / off heat pump dryer with the above-mentioned multiple operating modes. It can be adjusted according to the actual operating conditions to meet different needs and improve the user experience.

[0093] The dehumidification control method of the heat pump dryer provided by the present invention will be described below. The dehumidification control method of the heat pump dryer described below can be referred to in correspondence with the heat pump dryer described above.

[0094] According to an embodiment of the second aspect of the present invention, referring to Figure 4 As shown, the present invention also provides a dehumidification control method for the heat pump dryer of the above embodiments, mainly including:

[0095] S100: Obtain the dry bulb temperature and wet bulb temperature of the drying chamber.

[0096] S200: In response to the difference between the dry-bulb temperature of the drying chamber and the target dry-bulb temperature being greater than or equal to a first preset value, and the difference between the target wet-bulb temperature and the wet-bulb temperature of the drying chamber being less than or equal to a second preset value, the first air valve 2 is controlled to open.

[0097] Specifically, when the difference between the dry-bulb temperature of the drying chamber and the target dry-bulb temperature is greater than or equal to the first preset value, it indicates that the temperature inside the drying chamber is high. When the difference between the target wet-bulb temperature and the wet-bulb temperature of the drying chamber is less than or equal to the second preset value, it indicates that dehumidification is required. At this time, the first air valve 2 can be opened to discharge excess heat to the external evaporator 5, which then absorbs heat. The opening degree of the first air valve 2 can be adjusted according to the difference between the dry-bulb temperature of the drying chamber and the target dry-bulb temperature. Generally, the larger the difference, the larger the opening degree.

[0098] Therefore, in the dehumidification control method of the heat pump dryer of the present invention, when the dry bulb temperature in the drying chamber exceeds the target dry bulb temperature, the internal hot air can be discharged to the external evaporator 5 by controlling the first air valve 2, and the external evaporator 5 absorbs the heat of the discharged air to achieve the purpose of heat energy recovery.

[0099] Reference Figure 5As shown, the present invention also provides a dehumidification control method for the heat pump dryer of the above embodiments, mainly including:

[0100] S1. Obtain the dry-bulb temperature of the drying room.

[0101] S2. The opening of the second air valve 9 is adjusted based on the dry bulb temperature of the drying room to control the ratio of air volume entering the first flow channel 601 through the return air inlet 101 to the second chamber 7.

[0102] Specifically, the controller compares the detected dry-bulb temperature of the drying chamber with the target dry-bulb temperature. When the dry-bulb temperature of the drying chamber is lower than the target dry-bulb temperature, the temperature of the drying chamber is low. At this time, the second air valve 9 is closed to achieve low-temperature dehumidification. When the dry-bulb temperature of the drying chamber is greater than or equal to the target dry-bulb temperature, the temperature of the drying chamber is high. At this time, the second air valve 9 is opened to achieve high-temperature dehumidification. Furthermore, as the temperature inside the drying chamber gradually increases, the opening degree of the second air valve 9 increases to gradually reduce the amount of dehumidifying air entering the first flow channel 601, thereby reducing the flow rate of water vapor that exchanges heat with the internal evaporator 3 and achieving the purpose of improving the condensation effect.

[0103] Reference Figure 6 As shown, the dehumidification control method in this embodiment further includes the following steps:

[0104] S3. Obtain the wet-bulb temperature of the drying chamber.

[0105] S4. In response to the difference between the dry-bulb temperature of the drying chamber and the target dry-bulb temperature being greater than or equal to a first preset value, and the difference between the target wet-bulb temperature and the wet-bulb temperature of the drying chamber being less than or equal to a second preset value, control the first air valve 2 and the third air valve 12 to open.

[0106] Specifically, when the difference between the dry-bulb temperature of the drying chamber and the target dry-bulb temperature is greater than or equal to the first preset value, it indicates that the temperature inside the drying chamber is high. When the difference between the target wet-bulb temperature and the wet-bulb temperature of the drying chamber is less than or equal to the second preset value, it indicates that dehumidification is required. At this time, the first air valve 2 and the third air valve 12 can be opened. The first air valve 2 discharges excess heat to the external evaporator 5, and the external evaporator 5 absorbs and recovers heat, thereby improving the heating effect of the circulating heating unit. By opening the third air valve 12 in the third flow channel 603, the internal temperature can be reduced, which is beneficial to improving the condensation dehumidification effect.

[0107] Furthermore, the opening degree of the first air valve 2 and the third air valve 12 can be adjusted according to the difference between the dry bulb temperature of the drying room and the target dry bulb temperature. For example, multiple levels can be set according to the difference. Generally, the larger the difference, the higher the level and the larger the opening degree.

[0108] When the difference between the dry-bulb temperature in the drying chamber and the target dry-bulb temperature is zero, close the first air valve 2 and the third air valve 12.

[0109] Reference Figure 7 As shown, the dehumidification control method in this embodiment further includes the following steps:

[0110] S5. Obtain the wet-bulb temperature of the drying chamber, the ambient temperature, and the temperature inside the third flow channel 603.

[0111] S6. In response to the difference between the target dry-bulb temperature and the dry-bulb temperature of the drying chamber being greater than or equal to the third preset value, the difference between the ambient temperature and the temperature inside the third flow channel 603 being greater than or equal to the fourth preset value, and the difference between the target wet-bulb temperature and the wet-bulb temperature of the drying chamber being less than or equal to the second preset value, control the third air valve 12 and the fourth air valve 13 to open.

[0112] Specifically, when the difference between the target dry-bulb temperature and the dry-bulb temperature of the drying chamber is greater than or equal to the third preset value, it indicates that the temperature inside the drying chamber is low. When the difference between the ambient temperature and the temperature inside the third flow channel is greater than or equal to the fourth preset value, it indicates that the ambient temperature is high. When the difference between the target wet-bulb temperature and the wet-bulb temperature of the drying chamber is less than or equal to the second preset value, it indicates that dehumidification is required. At this time, the third air valve 12 and the fourth air valve 13 can be opened. Through the third air valve 12 and the fourth air valve 13, heat from the outside can be absorbed to achieve the purpose of increasing the temperature of the drying chamber.

[0113] Furthermore, the opening degree of the third air valve 12 and the fourth air valve 13 can be adjusted according to the difference between the target dry-bulb temperature and the dry-bulb temperature of the drying room. For example, multiple levels can be set according to the difference. Generally, the larger the difference, the higher the level and the larger the opening degree.

[0114] When the difference between the dry-bulb temperature in the drying chamber and the target dry-bulb temperature is zero, close the third air valve 12 and the fourth air valve 13.

[0115] It is understood that the target dry-bulb temperature, target wet-bulb temperature, first preset value, second preset value, third preset value and fourth preset value mentioned above in this invention can be designed according to actual drying needs, and are generally positive numbers. For example, the first preset value and the third preset value can be 0.5℃, the second preset value can be 0.2℃, and the fourth preset value can be 10℃.

[0116] On the other hand, the present invention also provides a drying room, comprising: a material room and a heat pump dryer of the above embodiment, wherein the material room is connected to the return air inlet 101 and the exhaust air outlet of the heat pump dryer respectively; or when performing dehumidification, the dehumidification control method of the heat pump dryer of the above embodiment is adopted.

[0117] Specifically, the high-humidity air generated during material drying in the material room is sent to the heat pump dryer through the return air vent 101. The dryer utilizes a circulating heating unit, heat exchanger 8, and various air valves for dehumidification. The resulting high-temperature, low-humidity air is then discharged into the material room through the exhaust vent to dry the materials, thus achieving circulation. The specific dehumidification process is described above and will not be repeated here.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A heat pump dryer, characterized in that, include: The casing is equipped with a return air vent and an exhaust air vent; A circulating heating unit, disposed within the casing, includes: a compressor, an internal evaporator, and a condenser connected together, the condenser being located at the exhaust port; and an external evaporator connected in parallel to the internal evaporator, the external evaporator being located outside the casing; The casing contains a first chamber where the internal evaporator is located and a second chamber where the condenser is located. The first chamber is connected to the second chamber, the first chamber is connected to the return air vent, and the second chamber is connected to the exhaust air vent. A first air valve is closable and disposed between the first chamber and the external evaporator to control the heat exchange between the air in the first chamber and the external evaporator. The casing is further provided with a heat exchanger and a second air valve. The heat exchanger forms a first flow channel with the casing and the second air valve. The heat exchanger forms a second flow channel with the casing and the inner evaporator. The first air valve is located on the side wall of the second flow channel near the outer evaporator. The heat exchanger forms a third flow channel with the inner evaporator and the casing. The third air valve is closable and is installed in the third flow channel to control the heat exchange between the air in the third flow channel and the outside. A fourth air valve is provided in the second chamber and can be opened and closed to control the heat exchange between the air in the second chamber and the outside. In the low-temperature closed-loop dehumidification mode, the first and second air valves are closed, while the third and fourth air valves are open. This allows the air flowing sequentially through the first, second, and third flow channels to exchange heat with the outside environment through the third air valve in the third flow channel, and then enter the second chamber through the fourth air valve for further heat exchange. After being heated by the condenser, the air is then discharged through the exhaust port.

2. The heat pump dryer according to claim 1, characterized in that, The second air valve forms a second chamber with the heat exchanger, the casing and the condenser; the second air valve is closable between the first flow channel and the second chamber, and is used to control the connection and disconnection of the return air port with the first flow channel and the second chamber; The first chamber includes: the first flow channel, the second flow channel, and the third flow channel.

3. The heat pump dryer according to claim 2, characterized in that, Also includes: A first temperature sensor is installed in the drying chamber to detect the dry-bulb temperature of the drying chamber. A second temperature sensor is installed in the drying chamber to detect the wet-bulb temperature of the drying chamber. The controller is electrically connected to the compressor, the first air valve, the second air valve, the third air valve, the fourth air valve, the first temperature sensor, and the second temperature sensor, respectively.

4. The heat pump dryer according to claim 3, characterized in that, Also includes: The third temperature sensor, electrically connected to the controller, is used to detect the ambient temperature. A fourth temperature sensor is disposed in the third flow channel and electrically connected to the controller, and is used to detect the temperature in the third flow channel.

5. The heat pump dryer according to any one of claims 1-4, characterized in that, The first chamber and / or the second chamber are each equipped with a fan.

6. A dehumidification control method for a heat pump dryer according to any one of claims 1-5, characterized in that, include: Obtain the dry bulb temperature and wet bulb temperature of the drying chamber; In response to the fact that the difference between the dry-bulb temperature of the drying chamber and the target dry-bulb temperature is greater than or equal to a first preset value, and the difference between the target wet-bulb temperature and the wet-bulb temperature of the drying chamber is less than or equal to a second preset value, the first air valve is controlled to open.

7. The dehumidification control method for a heat pump dryer according to claim 6, characterized in that, The step of controlling the opening of the first air valve specifically includes: adjusting the opening degree of the first air valve according to the difference between the dry bulb temperature of the drying chamber and the target dry bulb temperature.

8. A dehumidification control method for a heat pump dryer according to any one of claims 1-5, characterized in that, include: Obtain the dry-bulb temperature of the drying room; The opening of the second air valve is adjusted based on the dry bulb temperature of the drying chamber to control the ratio of air volume entering the first flow channel and the second chamber through the return air inlet.

9. The dehumidification control method for a heat pump dryer according to claim 8, characterized in that, It also includes the following steps: Obtain the wet-bulb temperature of the drying chamber; In response to the fact that the difference between the dry-bulb temperature of the drying chamber and the target dry-bulb temperature is greater than or equal to a first preset value, and the difference between the target wet-bulb temperature and the wet-bulb temperature of the drying chamber is less than or equal to a second preset value, the first air valve and the third air valve are controlled to open.

10. The dehumidification control method for a heat pump dryer according to claim 9, characterized in that, The steps of controlling the opening of the first air valve and the third air valve specifically include: adjusting the opening degree of the first air valve and the third air valve according to the difference between the dry bulb temperature of the drying chamber and the target dry bulb temperature.

11. The dehumidification control method for a heat pump dryer according to claim 8, characterized in that, It also includes the following steps: The wet-bulb temperature of the drying chamber, the ambient temperature, and the temperature inside the third flow channel are obtained. In response to the fact that the difference between the target dry-bulb temperature and the dry-bulb temperature of the drying chamber is greater than or equal to a third preset value, the difference between the ambient temperature and the temperature in the third flow channel is greater than or equal to a fourth preset value, and the difference between the target wet-bulb temperature and the wet-bulb temperature of the drying chamber is less than or equal to a second preset value, the third air valve and the fourth air valve are controlled to open.

12. The dehumidification control method for a heat pump dryer according to claim 11, characterized in that, The steps of controlling the opening of the third and fourth air valves specifically include: adjusting the opening degree of the third and fourth air valves according to the difference between the target dry-bulb temperature and the dry-bulb temperature of the drying chamber.

13. A drying room, characterized in that, include: The heat pump dryer according to any one of claims 1-5, or when performing dehumidification, adopts the dehumidification control method of the heat pump dryer according to any one of claims 6-12.

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