A heat pump drying system, a control method thereof, a heat pump clothes dryer, and a medium

Abstract

The present application relates to a kind of heat pump drying system and its control method, heat pump clothes dryer, medium, the method comprises the following steps: obtaining the current drying stage of heat pump clothes dryer;According to the current drying stage of heat pump clothes dryer Control four-way valve, bypass air valve, outer circulation air valve, fresh air valve, exhaust air valve switching.The present application simultaneously introduces the air of relatively low temperature and low humidity in room into evaporator by the high temperature and high humidity air of drying chamber outlet, greatly reduces evaporator load;At the same time, the compressor of heat pump system is placed in air duct, and the sensible heat of compressor is recovered to condenser inlet, and the condensing load is reduced.Correspondingly, the closure and opening of air port can be realized by corresponding air valve, the sensible heat of compressor and indoor waste heat can be used to the maximum extent, and it is more economical and energy-saving.

Description

Technical Field

[0001] This invention relates to the field of heat pump dryer technology, and particularly to a heat pump drying system and its control method, a heat pump dryer, and a medium. Background Technology

[0002] In traditional internal circulation heat pump drying systems, the heat pump system has a simple structure and single function, which cannot meet the different air quality requirements of each stage of drying, resulting in a large amount of energy waste.

[0003] In the early stages of drying, the air temperature inside the duct may be very low. At this time, the air saturation moisture content is low and the moisture absorption capacity is poor. The task of the heat pump system is to heat up quickly. However, at this time, the evaporator inlet air temperature is low and the evaporation load is extremely low, which poses a risk of liquid return. This causes the compressor to be unable to output quickly due to liquid return protection.

[0004] In the later stages of drying, once the moisture content of the clothes reaches the target value, the drying process is considered complete. At this point, the temperature inside the drying chamber is very high, and it is not allowed to open the door immediately to remove the clothes to prevent burns. To allow for timely removal of the clothes, the drying chamber is often cooled using circulating air, and the heat pump system is not running, which takes a long time. Summary of the Invention

[0005] In order to achieve the above-mentioned objectives and other advantages of the present invention, the first objective of the present invention is to provide a heat pump drying system, comprising: a compressor, a four-way valve, a condenser, a capillary tube, an evaporator, a bypass valve, an external circulation valve, an external circulation fan, an internal circulation fan, an exhaust valve, a fresh air valve, a throttling valve, an internal circulation air path, a first external circulation air path, a second external circulation air path, an exhaust air path, and a fresh air path;

[0006] The compressor is connected to the condenser and the evaporator via the four-way valve, and the condenser is connected to the evaporator via the throttle valve;

[0007] The condenser, the evaporator, and the drying chamber are connected by an internal circulation air duct, and the internal circulation fan is installed at the inlet of the drying chamber;

[0008] The first end of the bypass ventilation path is installed between the internal circulation fan and the condenser, the second end of the bypass ventilation path is installed between the condenser and the evaporator, and the bypass ventilation valve is installed on the second end of the bypass ventilation path;

[0009] The internal circulation air path is connected to the first external circulation air path and the second external circulation air path. The first external circulation air path is located between the condenser and the evaporator. The compressor is placed in the first external circulation air path. The external circulation fan is installed on the first external circulation air path. The second external circulation air path is located at the inlet of the condenser. The external circulation air valve is installed on the second external circulation air path.

[0010] The internal circulation air duct is connected to the exhaust air duct, the exhaust air duct is located at the outlet of the drying chamber, and the exhaust air valve is installed on the exhaust air duct;

[0011] The internal circulation air path is connected to the fresh air path, the fresh air path is located at the outlet of the evaporator, and the fresh air valve is installed on the fresh air path.

[0012] Furthermore, the throttle valve is a capillary tube.

[0013] A second objective of the present invention is to provide a heat pump dryer, comprising a dryer body and a heat pump drying system disposed within the dryer body.

[0014] A third objective of this invention is to provide a control method for a heat pump drying system, comprising the following steps:

[0015] Obtain the current drying stage of the heat pump dryer;

[0016] The control switches between the four-way valve, bypass air valve, external circulation air valve, fresh air valve, and exhaust air valve according to the current drying stage of the heat pump dryer.

[0017] Furthermore, the drying stage of the heat pump dryer includes a pre-drying stage and a post-drying stage.

[0018] Furthermore, the step of controlling the switching of the four-way valve, bypass air valve, external circulation air valve, fresh air valve, and exhaust air valve according to the current drying stage of the heat pump dryer includes the following steps:

[0019] When the current drying stage of the heat pump dryer is the early drying stage, the evaporator is used as a condenser by switching the four-way valve, the bypass air valve is controlled to operate in the closed state, and the external circulation air valve is controlled to operate in the open state.

[0020] When the current drying stage of the heat pump dryer is the later stage of drying, the evaporator is used as an air-cooled evaporator by switching the four-way valve, the compressor and the condenser are switched to external circulation cooling mode, the bypass air valve is controlled to open, and the external circulation air valve, the exhaust air valve and the fresh air valve are controlled to close.

[0021] Furthermore, the specific method of using the evaporator as a condenser by switching the four-way valve involves connecting the outlet of the compressor to the outlet of the evaporator and connecting the inlet of the compressor to the inlet of the condenser by switching the four-way valve.

[0022] Furthermore, the specific method of using the evaporator as an air-cooled evaporator by switching the four-way valve involves connecting the compressor inlet to the evaporator outlet and connecting the compressor outlet to the condenser inlet by switching the four-way valve.

[0023] Furthermore, the determination of the drying stage of the heat pump dryer includes the following steps:

[0024] Acquire the collected temperature and / or air humidity and clothing humidity values ​​of the internal circulation duct;

[0025] Determine whether the collected temperature and / or humidity of the internal circulation duct have reached the preset value for the early stage of drying;

[0026] If so, the current drying stage of the drying process is determined to be the pre-drying stage;

[0027] Otherwise, determine whether the collected clothing humidity value has reached the preset value for the later stage of drying;

[0028] If so, the current drying stage of the drying process is determined to be the cooling stage in the later stage of drying.

[0029] A fourth objective of this invention is to provide a computer-readable storage medium having program instructions stored thereon, which, when executed, implement a control method for a heat pump drying system.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] This invention provides a semi-closed heat pump drying system that simultaneously introduces relatively low-temperature, low-humidity air from the drying chamber outlet into the evaporator, significantly reducing the evaporator load. Simultaneously, the heat pump system's compressor is placed within the air duct, recovering its sensible heat before the condenser inlet, further reducing the condensing load. Correspondingly, the opening and closing of the air vents can be achieved through corresponding air valves, maximizing the utilization of compressor sensible heat and indoor waste heat, resulting in greater economic efficiency and energy savings.

[0032] This invention provides a novel heat pump drying system with multiple adjustable operating modes and selective control of system outlet air quality based on the drying cycle. The invention optimizes the duct design by adding a bypass ventilation path between the evaporator and condenser, and incorporating a four-way valve component into the heat pump system. During the initial drying phase, the evaporator is used as a condenser by switching the four-way valve, with the bypass ventilation valve closed and the external circulation valve open. At this point, only the condenser is a heat-generating component within the duct system, eliminating heat loss from the evaporator and enabling rapid temperature rise within the duct. Simultaneously, waste heat from the compressor is recovered within the external circulation duct. The air temperature after compressor waste heat recovery is higher than the ambient temperature, increasing the evaporator load and effectively preventing liquid backflow in low-temperature environments. This solves the problem of slow temperature rise during the initial drying phase in heat pump drying systems and significantly reduces the risk of liquid backflow.

[0033] This invention provides a novel heat pump drying system that solves the problem of excessively long cooling time in the later stages of drying. A four-way valve is added to the heat pump system, along with a bypass ventilation path between the evaporator and condenser. When drying is complete and the cooling phase begins, the bypass ventilation valve is opened, while the external circulation valve, exhaust valve, and fresh air valve are closed, creating a new internal circulation duct. This duct contains only one evaporator. By switching the four-way valve, the evaporator functions as an air-cooled evaporator, while the compressor and condenser of the heat pump system switch to external circulation cooling. This allows for rapid cooling during the later stages of drying, significantly shortening the drying cycle.

[0034] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail below with reference to the accompanying drawings. Attached Figure Description

[0035] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0036] Figure 1 This is a schematic diagram of a heat pump drying system according to Example 1;

[0037] Figure 2 This is a schematic diagram of the heat pump drying system for the initial stage of drying.

[0038] Figure 3 This is a schematic diagram of the heat pump drying system for the later stages of drying.

[0039] Figure 4This is a schematic diagram of the heat pump dryer in Example 2;

[0040] Figure 5 Here is a flowchart of a backflow prevention control method for a heat pump drying system according to Example 3;

[0041] Figure 6 This is a block diagram of the computer-readable storage medium in Example 4.

[0042] In the attached diagram: 1. Compressor; 2. Four-way valve; 3. Condenser; 4. Capillary tube; 5. Evaporator; 6. Bypass valve; 7. External circulation valve; 8. External circulation fan; 9. Internal circulation fan; 10. Drying chamber; 11. Exhaust valve; 12. Fresh air valve. Detailed Implementation

[0043] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0044] Example 1

[0045] A heat pump drying system, such as Figure 1 As shown, it includes: compressor 1, four-way valve 2, condenser 3, capillary tube 4, evaporator 5, bypass valve 6, external circulation valve 7, external circulation fan 8, internal circulation fan 9, exhaust valve 11, fresh air valve 12, throttle valve, internal circulation air path, first external circulation air path, second external circulation air path, exhaust air path, and fresh air path;

[0046] The compressor 1 is connected to the condenser 3 and the evaporator 5 through the four-way valve 2. The condenser 3 is connected to the evaporator 5 through the throttle valve. In this embodiment, the throttle valve is a capillary tube 4.

[0047] The condenser 3, evaporator 5, and drying chamber 10 are connected by an internal circulation air duct, and the internal circulation fan 9 is installed at the inlet of the drying chamber 10.

[0048] The first end of the bypass ventilation path is installed between the internal circulation fan 9 and the condenser 3, the second end of the bypass ventilation path is installed between the condenser 3 and the evaporator 5, and the bypass ventilation valve 6 is installed on the second end of the bypass ventilation path;

[0049] The internal circulation air path is connected to the first external circulation air path and the second external circulation air path. The first external circulation air path is located between the condenser 3 and the evaporator 5. The compressor 1 is placed in the first external circulation air path. The external circulation fan 8 is installed on the first external circulation air path. The second external circulation air path is located at the inlet of the condenser 3. The external circulation air valve 7 is installed on the second external circulation air path.

[0050] The internal circulation air duct is connected to the exhaust air duct, and the exhaust air duct is located at the outlet of the drying chamber 10. The exhaust air valve 11 is installed on the exhaust air duct.

[0051] The internal circulation air path is connected to the fresh air path. The fresh air path is located at the outlet of the evaporator 5, and the fresh air valve 12 is installed on the fresh air path.

[0052] This embodiment optimizes the air duct design by adding a bypass air path between the evaporator 5 and the condenser 3, and adding a four-way valve 2 component to the heat pump system. The high-temperature, high-humidity air discharged from the outlet of the drying chamber 10 is simultaneously introduced into the evaporator 5 along with relatively low-temperature, low-humidity air from inside the chamber, significantly reducing the load on the evaporator 5. At the same time, the compressor 1 of the heat pump system is placed within the air duct, recovering the sensible heat of the compressor 1 before reaching the inlet of the condenser 3, reducing the condensation load. Multiple adjustable operating modes are available, allowing selective control of the system outlet air quality according to the drying cycle. Correspondingly, the opening and closing of the air vents can be achieved through corresponding air valves, maximizing the utilization of the sensible heat of the compressor 1 and the waste heat from inside the chamber, resulting in greater economic efficiency and energy savings. A detailed description of the control method for the heat pump drying system can be found in the corresponding description in the following method embodiment, and will not be repeated here.

[0053] like Figure 2 As shown, in the early stage of drying, the evaporator 5 is used as a condenser by switching the four-way valve 2, that is... Figure 2 In this configuration, the outlet of compressor 1 is connected to the outlet of evaporator 5, and the inlet of compressor 1 is connected to the inlet of condenser 3. The bypass vent valve 6 is closed, while the external circulation vent valve 7 is opened. At this point, only the condenser 3 is a heat-generating component within the duct system, eliminating heat loss from the evaporator 5 and enabling rapid temperature rise within the duct. Simultaneously, waste heat from compressor 1 is recovered within the external circulation duct. The air temperature after waste heat recovery is higher than the ambient temperature, increasing the load on evaporator 5 and effectively preventing liquid return in low-temperature environments. This solves the problem of slow temperature rise in the early stages of drying in heat pump drying systems and significantly reduces the risk of liquid return.

[0054] like Figure 3 As shown, when drying is complete and the cooling stage begins, a completely new internal circulation air duct is established by opening the bypass ventilation valve 6 and closing the external circulation air valve 7, exhaust air valve 11, and fresh air valve 12. This air duct contains only one evaporator, which is then switched using the four-way valve 2 to function as an air-cooled evaporator. Figure 3 In this process, the outlet of compressor 1 is connected to the inlet of condenser 3, and the inlet of compressor 1 is connected to the outlet of the heat pump system. Simultaneously, compressor 1 and condenser 3 of the heat pump system are switched to external circulation cooling. This solves the problem of excessively long cooling time in the later stages of drying, enabling rapid cooling using the heat pump system in the later stages of drying, thus significantly shortening the drying cycle.

[0055] Example 2

[0056] A type of heat pump dryer, such as Figure 4 As shown, the system includes a dryer body and a heat pump drying system disposed within the dryer body. For a detailed description of the heat pump drying system, please refer to the corresponding description in the above system embodiments, which will not be repeated here.

[0057] Example 3

[0058] Example 1 provides a control method for a heat pump drying system, such as... Figure 5 As shown, it includes the following steps:

[0059] During the early stages of drying, the air temperature inside the duct may be very low. At this time, the air saturation moisture content is low and the moisture absorption capacity is poor. The task of the heat pump system is to heat up quickly. However, at this time, the air inlet temperature of evaporator 5 is low and the evaporation load is extremely low, which poses a risk of liquid return. As a result, compressor 1 cannot output quickly due to liquid return protection.

[0060] In the later stages of drying, once the moisture content of the clothes reaches the target value, the drying process is considered complete. At this point, the temperature inside the drying chamber is very high, and it is not allowed to open the door immediately to remove the clothes to prevent burns. In order to remove the clothes in time, the drying chamber is often cooled by circulating air, and the heat pump system does not run, which takes a long time.

[0061] Therefore, it is necessary to control the different drying stages of the drying process.

[0062] The current drying stage of the heat pump dryer is determined. In this embodiment, the drying stage of the heat pump dryer includes an early drying stage and a late drying stage. The early drying stage involves slow temperature rise, while the late drying stage involves excessively long cooling time. Determining the drying stage of the heat pump dryer includes the following steps:

[0063] Since the air temperature inside the duct may be very low in the early stage of drying, the saturated moisture content of the air is low. Therefore, the temperature and / or moisture content of the air in the internal circulation duct can be collected to make a judgment.

[0064] Acquire the collected temperature and / or humidity of the internal circulation duct;

[0065] Determine whether the collected temperature and / or humidity of the internal circulation duct have reached the preset value for the early stage of drying;

[0066] If so, the current drying stage of the drying process is determined to be the pre-drying stage;

[0067] Since the drying process is considered complete once the moisture content of the clothes reaches the target value in the later stages of drying, the clothes then enter the cooling phase. Therefore, this can be determined by collecting the moisture content of the clothes.

[0068] Obtain the collected humidity values ​​of the clothing;

[0069] Determine whether the collected humidity value of the clothes has reached the preset value for the later stage of drying;

[0070] If so, the current drying stage of the drying process is determined to be the cooling stage in the later stage of drying;

[0071] Otherwise, the temperature and / or humidity of the air in the internal circulation duct, as well as the humidity of the clothes, will be continuously collected and judged to determine the current drying stage.

[0072] The system controls the switching of four-way valve 2, bypass air valve, external circulation air valve 7, fresh air valve 12, and exhaust air valve 11 according to the current drying stage of the heat pump dryer. Specifically, this includes the following steps:

[0073] When the heat pump dryer is in the early drying stage, the evaporator 5 is used as a condenser by switching the four-way valve 2. Specifically, the outlet of compressor 1 is connected to the outlet of evaporator 5, and the inlet of compressor 1 is connected to the inlet of condenser 3 by switching the four-way valve 2. The bypass air valve is controlled to be closed, and the external circulation air valve 7 is controlled to be open. At this time, there is only one heating component, condenser 3, in the air duct system, and there is no heat loss from evaporator 5, which can achieve the rapid temperature rise requirement in the air duct. At the same time, the waste heat of compressor 1 is recovered in the external circulation air duct. The air temperature after the waste heat of compressor 1 is recovered is higher than the ambient temperature, which can increase the load on evaporator 5. In low-temperature environments, it can effectively prevent liquid return from the heat pump system. This solves the problem of slow temperature rise in the early drying stage of the heat pump drying system, and greatly reduces the risk of liquid return.

[0074] When the current drying stage of the heat pump dryer is the later stage of drying, there is only one evaporator inside the air duct. By switching the four-way valve 2, the evaporator 5 is used as an air-cooled evaporator. Specifically, by switching the four-way valve 2, the inlet of the compressor 1 is connected to the outlet of the evaporator 5, and the outlet of the compressor 1 is connected to the inlet of the condenser 3. The compressor 1 and the condenser 3 are switched to external circulation cooling mode. The bypass air valve is controlled to open, and the external circulation air valve 7, exhaust air valve 11, and fresh air valve 12 are controlled to close. A brand-new internal circulation air duct is established, which can achieve rapid cooling by utilizing the heat pump system in the later stage of drying, greatly shortening the drying cycle.

[0075] This invention features multiple adjustable operating modes and allows for selective control of system outlet air quality based on the drying cycle.

[0076] Example 4

[0077] A computer-readable storage medium, such as Figure 6As shown, it stores program instructions, which, when executed, implement a method for preventing liquid backflow in a heat pump drying system. For a detailed description of the method, please refer to the corresponding description in the above method embodiments; it will not be repeated here.

[0078] Example 5

[0079] A computer program product includes a computer program / instructions that, when executed by a processor, implement a method for preventing liquid backflow in a heat pump drying system. A detailed description of the method can be found in the corresponding descriptions in the above method embodiments, and will not be repeated here.

[0080] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0081] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0082] The above are merely embodiments of this specification and are not intended to limit the scope of the one or more embodiments herein. For those skilled in the art, various modifications and variations can be made to the one or more embodiments of this specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the one or more embodiments of this specification should be included within the scope of the claims of the one or more embodiments of this specification.

Claims

1. A heat pump drying system, characterized in that, include: Compressor, four-way valve, condenser, capillary tube, evaporator, bypass valve, external circulation valve, external circulation fan, internal circulation fan, exhaust valve, fresh air valve, throttle valve, internal circulation air path, first external circulation air path, second external circulation air path, exhaust air path, fresh air path, drying chamber, bypass ventilation path; The compressor is connected to the condenser and the evaporator via the four-way valve, and the condenser is connected to the evaporator via the throttle valve; The condenser, the evaporator, and the drying chamber are connected by an internal circulation air duct, and the internal circulation fan is installed at the inlet of the drying chamber; The first end of the bypass ventilation path is installed between the internal circulation fan and the condenser, the second end of the bypass ventilation path is installed between the condenser and the evaporator, and the bypass ventilation valve is installed on the second end of the bypass ventilation path; The internal circulation air path is connected to the first external circulation air path and the second external circulation air path. The first external circulation air path is located between the condenser and the evaporator. The compressor is placed in the first external circulation air path. The external circulation fan is installed on the first external circulation air path. The second external circulation air path is located at the inlet of the condenser. The external circulation air valve is installed on the second external circulation air path. The internal circulation air duct is connected to the exhaust air duct, the exhaust air duct is located at the outlet of the drying chamber, and the exhaust air valve is installed on the exhaust air duct; The internal circulation air path is connected to the fresh air path, the fresh air path is located at the outlet of the evaporator, and the fresh air valve is installed on the fresh air path.

2. The heat pump drying system according to claim 1, characterized in that: The throttling valve is a capillary tube.

3. A heat pump clothes dryer, characterized in that: It includes a dryer body and a heat pump drying system as described in any one of claims 1 to 2 disposed within the dryer body.

4. A control method for a heat pump drying system as described in any one of claims 1 to 2, characterized in that, Includes the following steps: Obtain the current drying stage of the heat pump dryer; The control switches between the four-way valve, bypass air valve, external circulation air valve, fresh air valve, and exhaust air valve according to the current drying stage of the heat pump dryer.

5. The control method for the heat pump drying system according to claim 4, characterized in that: The drying stages of the heat pump dryer include the pre-drying stage and the post-drying stage.

6. The control method for the heat pump drying system according to claim 5, characterized in that, The process of controlling the switching of the four-way valve, bypass air valve, external circulation air valve, fresh air valve, and exhaust air valve according to the current drying stage of the heat pump dryer includes the following steps: When the current drying stage of the heat pump dryer is the early drying stage, the evaporator is used as a condenser by switching the four-way valve, the bypass air valve is controlled to operate in the closed state, and the external circulation air valve is controlled to operate in the open state. When the current drying stage of the heat pump dryer is the later stage of drying, the evaporator is used as an air-cooled evaporator by switching the four-way valve, the compressor and the condenser are switched to external circulation cooling mode, the bypass air valve is controlled to open, and the external circulation air valve, the exhaust air valve and the fresh air valve are controlled to close.

7. The control method for the heat pump drying system according to claim 6, characterized in that: The specific method of using the evaporator as a condenser by switching the four-way valve involves connecting the outlet of the compressor to the outlet of the evaporator and connecting the inlet of the compressor to the inlet of the condenser by switching the four-way valve.

8. The control method for the heat pump drying system according to claim 6, characterized in that: The specific method of using the evaporator as an air-cooled evaporator by switching the four-way valve involves connecting the compressor inlet to the evaporator outlet and connecting the compressor outlet to the condenser inlet by switching the four-way valve.

9. The control method for the heat pump drying system according to claim 5, characterized in that, The determination of the drying stage of the heat pump dryer includes the following steps: Acquire the collected temperature and / or air humidity and clothing humidity values ​​of the internal circulation duct; Determine whether the collected temperature and / or humidity of the internal circulation duct have reached the preset value for the early stage of drying; If so, the current drying stage of the drying process is determined to be the pre-drying stage; Otherwise, determine whether the collected clothing humidity value has reached the preset value for the later stage of drying; If so, the current drying stage of the drying process is determined to be the cooling stage in the later stage of drying.

10. A computer-readable storage medium, characterized in that, It stores program instructions, which, when executed, implement the control method as described in claim 4.

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