Heat pump drying system and its control method

Abstract

This invention discloses a heat pump drying system and its control method. The heat pump drying system includes: a dehumidification and reheat heat pump system; a hot water storage tank located below a first evaporator for storing condensate produced by the first evaporator; and a heat recovery heat pump system including: a second compressor, a second condenser, a second throttling device, and a second evaporator connected in sequence; the second evaporator is connected to the hot water storage tank to provide heat to the second condenser using water from the tank; and the second condenser is connected to the air inlet of the drying chamber for secondary heating of the incoming air. This invention solves the problem of ineffective utilization of condensate and heat waste in existing heat pump drying systems by fully utilizing the heat from dehumidification condensate, increasing the supply air temperature, and improving the overall energy efficiency and temperature control range of the heat pump drying system.

Description

Technical Field

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

[0002] Heat pump drying systems are widely used in agriculture, industry, and processing of crops, fruits, vegetables, and sludge. They utilize the principle of high-temperature heat pumps to raise the temperature in the drying / baking room and remove moisture from the dried materials. During the dehumidification process, the evaporator of the heat pump produces a large amount of condensate. The temperature of this condensate in the heat pump drying system is relatively high, typically above 30℃ to 40℃ or even higher. Directly dissipating this heat results in significant heat waste.

[0003] Patent No. 202010924128.2 discloses a heat pump drying system. However, this system mainly relies on opening a bypass duct to introduce a portion of the humid and hot air in the drying chamber into the condenser, where it is combined with the dehumidified air cooled from the evaporator and reheated. The high-temperature hot air is then sent to the drying chamber. While this humid air heat bypass solution addresses the low exhaust air volume issue to some extent, the return air temperature in the drying chamber is relatively low, the moisture content of the combined air is increased, the temperature increase after reheating is limited, and the moisture content of the hot air sent to the drying chamber is relatively high. This results in a reduced overall drying effect, and the heat carried by the condensate is not effectively utilized, leading to waste.

[0004] There is currently no effective solution to the problem of inefficient utilization of condensate and heat waste in heat pump drying systems. Summary of the Invention

[0005] This invention provides a heat pump drying system and its control method to at least solve the problem of ineffective utilization of condensate and heat waste in existing heat pump drying systems.

[0006] To address the aforementioned technical problems, according to one aspect of the present invention, a heat pump drying system is provided, applied in a drying room. The heat pump drying system includes: a dehumidification and reheat heat pump system, comprising: a first compressor, a first condenser, a first throttling device, and a first evaporator connected in sequence; wherein the first evaporator is connected to the return air inlet of the drying room and is used to condense the return air of the drying room, reduce the humidity of the return air, and then introduce it into the air inlet of the drying room; the first condenser is connected to the air inlet of the drying room and is used to heat the air entering the drying room; a hot water storage tank is located below the first evaporator and is used to store the condensate produced by the first evaporator; a heat recovery heat pump system includes: a second compressor, a second condenser, a second throttling device, and a second evaporator connected in sequence; wherein the second evaporator is connected to the hot water storage tank and is used to provide heat to the second condenser using the water in the hot water storage tank; the second condenser is located on the air supply duct from the first evaporator to the first condenser and is used to reheat the return air entering the first condenser.

[0007] Furthermore, it also includes: an air valve, located on the air supply duct from the first evaporator to the first condenser, used to adjust the ratio of return air directly entering the first condenser and flowing through the second condenser, thereby adjusting the air inlet temperature of the drying chamber.

[0008] Furthermore, it also includes: a heat exhaust and cooling system, one end of which is connected to the heat exhaust outlet of the drying room, and the other end of which is connected to the hot water storage tank, for absorbing the heat from the gas discharged from the heat exhaust outlet and heating the water in the hot water storage tank.

[0009] Furthermore, the heat dissipation and cooling system includes: a third compressor, a third condenser, a third throttling device, and a third evaporator connected in sequence; wherein, the third evaporator is located at the heat dissipation outlet of the drying chamber, and the third condenser is connected to the hot water storage tank for heating the water in the hot water storage tank using the heat from the third condenser.

[0010] Furthermore, the heat exhaust and cooling system includes: a gas-water heat exchanger located at the heat exhaust outlet of the drying chamber, the gas-water heat exchanger being connected to the hot water storage tank, used to absorb the heat from the gas at the heat exhaust outlet and heat the water in the hot water storage tank.

[0011] Furthermore, the second evaporator includes a first sub-evaporator and a second sub-evaporator arranged in parallel. The first sub-evaporator is an air-side evaporator, and the second sub-evaporator is a water-side evaporator. The second sub-evaporator is connected to the hot water storage tank, and a first water pump is installed on the pipeline connecting the second sub-evaporator and the hot water storage tank. A second water pump is installed on the pipeline connecting the heat dissipation and cooling system to the hot water storage tank.

[0012] According to another aspect of the present invention, a heat pump drying system control method is provided, applied to the heat pump drying system as described above. The method includes: detecting the inlet air temperature of the drying chamber and determining whether the inlet air temperature has reached a preset temperature; if so, controlling the heat pump drying system to maintain its current operating state; otherwise, controlling the heat recovery heat pump system to start and perform secondary heating on the inlet air entering the drying chamber.

[0013] Furthermore, the control of the heat recovery heat pump system includes: controlling the second compressor of the heat recovery heat pump system to start; adjusting the opening of the air valve to adjust the air flow through the second condenser, thereby adjusting the air inlet temperature of the drying room until the air inlet temperature reaches the preset temperature.

[0014] Furthermore, it also includes: detecting whether the drying room needs heat exhaust; if so, controlling the heat exhaust and cooling system to start; otherwise, controlling the heat pump drying system to maintain its current operating state.

[0015] According to another aspect of the present invention, a storage medium containing computer-executable instructions is provided, which, when executed by a computer processor, are used to perform the heat pump drying system control method described above.

[0016] This invention addresses heat waste in heat pump drying systems by proposing a condensate heat recovery heat pump drying system. This system includes a dehumidification and reheat heat pump system, as well as a water collection device to collect condensate generated by the evaporator of the dehumidification and reheat heat pump system. To effectively utilize the collected condensate, a hot water storage tank is also provided to store the condensate, along with a heat recovery heat pump system. The water in the storage tank provides heat to the condenser, which is then used to reheat the incoming air into the drying chamber, increasing the air inlet temperature. By coupling the condensate heat recovery heat pump system, the heat from the dehumidified condensate is fully utilized, avoiding the problem of low reheat air temperature after dehumidification and cooling in the heat pump drying system. This increases the heat and temperature of the supplied air, significantly reducing energy waste and improving the overall energy efficiency and temperature control range of the heat pump drying system. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of an optional structure of a heat pump drying system according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of another optional structure of the heat pump drying system according to an embodiment of the present invention;

[0019] Figure 3 This is an optional flowchart of a heat pump drying system control method according to an embodiment of the present invention.

[0020] Explanation of reference numerals in the attached figures:

[0021] 1. First compressor; 2. First condenser; 3. First throttling device; 4. First evaporator; 5. Drying chamber; 6. Water collection device; 7. Hot water storage tank; 8. Second compressor; 9. Second condenser; 10. Second throttling device; 11. First sub-evaporator; 12. Second sub-evaporator; 13. Air valve; 14. Third compressor; 15. Third condenser; 16. Third throttling device; 17. Third evaporator; 18. Gas-water heat exchanger; 19. Second water pump; 20. First water pump. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0024] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0025] It should be understood that although the terms first, second, third, etc., may be used to describe controllers in embodiments of the present invention, these controllers should not be limited to these terms. These terms are only used to distinguish controllers connected to different devices. For example, without departing from the scope of embodiments of the present invention, a first controller may also be referred to as a second controller, and similarly, a second controller may also be referred to as a first controller.

[0026] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0027] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0028] The optional embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0029] Example 1

[0030] In a preferred embodiment 1 of the present invention, a heat pump drying system is provided, which is applied to a drying room 5 for drying or baking.

[0031] Specifically Figure 1 This diagram illustrates one possible structural design of the heat pump drying system, such as... Figure 1 As shown, the heat pump drying system includes:

[0032] The dehumidification and reheat heat pump system includes: a first compressor 1, a first condenser 2, a first throttling device 3, and a first evaporator 4 connected in sequence; wherein, the first evaporator 4 is connected to the return air inlet of the drying chamber 5, and is used to condense the return air of the drying chamber 5, reducing the humidity of the return air before it is introduced into the air inlet of the drying chamber 5; the first condenser 2 is connected to the air inlet of the drying chamber 5, and is used to heat the air entering the drying chamber 5; when the dehumidification and reheat heat pump system is working, it dehumidifies the air extracted from the drying chamber 5, generating a large amount of condensate, and then reheats the dehumidified air before sending it into the drying chamber 5; the first condenser 2 and the first evaporator 4 are located in two separate chambers, such as... Figure 1 As shown, this avoids mixing of return air and intake air, which reduces the intake effect;

[0033] The water collection device 6 is located below the first evaporator 4 and is used to collect the condensate produced by the first evaporator 4. The water collection device 6 can be a water collection tray or other water collection forms, as long as it can collect the condensate and prevent condensate leakage.

[0034] Hot water storage tank 7, the inlet of hot water storage tank 7 is connected to the outlet of water collection device 6, and is used to store condensate;

[0035] The heat recovery heat pump system includes: a second compressor 8, a second condenser 9, a second throttling device 10, and a second evaporator connected in sequence; wherein, the second evaporator is connected to a hot water storage tank 7, and is used to provide heat to the second condenser 9 using water from the hot water storage tank 7; the second condenser 9 is connected to the air inlet of the drying chamber 5, and is used to reheat the air entering the drying chamber 5. Figure 1 As shown, the hot water storage tank 7 exchanges heat with the second evaporator through a water circuit to increase the temperature of the second evaporator, thereby providing a higher-temperature refrigerant to the second condenser 9, improving the heat exchange effect of the second condenser 9, and increasing the inlet air temperature. The instantaneous heat recovery heat pump system fully utilizes the heat in the condensate to reheat the dehumidified and cooled air once, and then supplies it to a conventional dehumidification and reheat heat pump for a second reheat, increasing the heat supply of the air and raising the supply air temperature.

[0036] In the above embodiments, to address heat waste in heat pump drying systems, a condensate heat recovery heat pump drying system is proposed. This system includes a dehumidification and reheat heat pump system, as well as a water collection device to collect condensate generated by the evaporator of the dehumidification and reheat heat pump system. To effectively utilize the collected condensate, a hot water storage tank is also provided to store the condensate, along with a heat recovery heat pump system. The water in the storage tank provides heat to the condenser, thereby reheating the incoming air into the drying chamber and increasing its temperature. By coupling the condensate heat recovery heat pump system, the heat from the dehumidified condensate is fully utilized, avoiding the problem of low reheat air temperature after dehumidification and cooling in the heat pump drying system. This increases the heat and temperature of the supplied air, significantly reducing energy waste and improving the overall energy efficiency and temperature control range of the heat pump drying system.

[0037] like Figure 1 As shown, the system also includes: a damper 13, located on the air supply duct from the first evaporator 4 to the first condenser 2, used to adjust the ratio of return air directly entering the first condenser 2 and flowing through the second condenser 9, thereby adjusting the inlet air temperature of the drying chamber 5. By adjusting the proportional opening of the damper 13, the airflow through the second condenser 9 is adjusted, thereby determining the proportion of primary reheat and achieving temperature control of the air before secondary reheat.

[0038] To further improve energy efficiency, this system also includes a heat dissipation and cooling system, one end of which is connected to the heat dissipation outlet of the drying chamber 5, and the other end is connected to the hot water storage tank 7. This system absorbs the heat from the exhaust gases at the heat dissipation outlet and heats the water in the hot water storage tank 7. When the drying chamber 5 needs cooling or when heat dissipation is required after drying, the heat dissipation and cooling system utilizes the principle of a heat pump to absorb heat from the drying chamber 5 and transfer this heat to the hot water storage tank 7 for subsequent reuse.

[0039] Optionally, such as Figure 1 As shown, the heat dissipation and cooling system includes a third compressor 14, a third condenser 15, a third throttling device 16, and a third evaporator 17 connected in sequence. The third evaporator 17 is located at the heat dissipation outlet of the drying chamber 5, and the third condenser 15 is connected to the hot water storage tank 7, used to heat the water in the tank using the heat from the third condenser 15. Using a heat pump system can efficiently collect and utilize heat, improving energy efficiency.

[0040] Figure 2 This illustrates an alternative implementation method for the heat dissipation and cooling system, such as... Figure 2 As shown, the heat dissipation and cooling system includes an air-water heat exchanger 18 located at the heat dissipation outlet of the drying chamber 5. The air-water heat exchanger 18 is connected to the hot water storage tank 7 and is used to absorb the heat from the heat dissipation outlet gas to heat the water in the hot water storage tank 7. The heat dissipation and cooling heat pump heat storage system can be realized by an air-water heat exchanger. Although its cooling rate is lower than that of a heat pump system, it does not require additional energy consumption, which helps to improve the overall system energy efficiency.

[0041] like Figure 1 As shown, the second evaporator includes a first sub-evaporator 11 and a second sub-evaporator 12 connected in parallel. The first sub-evaporator 11 is an air-side evaporator, and the second sub-evaporator 12 is a water-side evaporator. The second sub-evaporator 12 is connected to the hot water storage tank 7, and a first water pump 20 is installed on the pipeline connecting the second sub-evaporator 12 to the hot water storage tank 7. A second water pump 19 is installed on the pipeline connecting the heat dissipation and cooling system to the hot water storage tank 7. The water pumps can accelerate the circulation of water and increase the water flow, thus improving the heat exchange effect.

[0042] The following is based on Figure 1 Taking an example, let's illustrate the specific workflow of a heat pump drying system:

[0043] (1) Dehumidification and reheat heat pump system

[0044] After the gaseous refrigerant enters the compressor through the compressor suction port, it is compressed into a high-pressure, high-temperature gaseous refrigerant and enters the first condenser 2. It heats the dehumidified and cooled air from the first evaporator 4 into dehumidified and cooled air at an even higher temperature and sends it into the drying room 5. At the same time, the refrigerant condenses into a high-pressure liquid refrigerant. After being throttled, depressurized, and cooled by the first throttling valve, it enters the first evaporator 4.

[0045] After throttling, the refrigerant absorbs heat from the high-humidity and high-temperature air drawn in from the drying chamber 5, forming a low-pressure gaseous refrigerant. The high-humidity and high-temperature air flows through the fin surface of the first evaporator 4 and releases heat, condensing to form a large amount of medium-temperature condensate, thus achieving cooling and dehumidification.

[0046] The low-pressure gaseous refrigerant is drawn back into the compressor for compression, and this process is repeated.

[0047] (2) Heat pump system for heat recovery of coupled condensate

[0048] When the above (1) dehumidification and reheat heat pump system is running, the first evaporator 4 generates a large amount of medium-temperature condensate, which is collected in the water collection pan and stored in the hot water storage tank 7.

[0049] The low-pressure, low-temperature gaseous refrigerant from the second evaporator is drawn into the compressor and compressed to form a high-pressure, high-temperature gaseous refrigerant. It then enters the second condenser 9, where it reheats the air dehumidified by the first evaporator 4, causing the refrigerant to condense into a high-pressure liquid refrigerant. After passing through the second throttling valve to reduce pressure and temperature, it enters the second evaporator, where it absorbs heat from the condensate in the hot water storage tank 7, causing the refrigerant to evaporate into a low-pressure, low-temperature gaseous refrigerant. This process is repeated.

[0050] The system takes into account the insufficient heat of the condensate in the hot water storage tank 7 or the very little recoverable heat, such as when there is relatively little condensate or the temperature is low in the early stage of drying. It adds an air-side evaporator to absorb enough heat from the air. The flow rate can be distributed through the opening of the second throttle valve to achieve sufficient reheat.

[0051] (3) Heat dissipation and cooling system

[0052] In the drying process, there are situations where the drying chamber 5 needs to exhaust heat or cool down. In this case, the heat pump principle is fully utilized to absorb the heat in the drying chamber 5 and transfer it to the hot water storage tank 7. The specific process is as follows:

[0053] The low-pressure gaseous refrigerant from the third evaporator 17 is drawn into the third compressor 14, where it is compressed into a high-pressure, high-temperature gaseous refrigerant. It then enters the third condenser 15 to release heat to the water in the hot water storage tank 7, condensing into a high-pressure liquid refrigerant. After being throttled, its pressure and temperature are reduced, and it enters the third evaporator 17 to absorb heat from the medium- and high-temperature air in the drying chamber 5 and cool it down. At the same time, the refrigerant evaporates into a low-pressure gaseous refrigerant and enters the compressor again, repeating this process.

[0054] The heat pump drying system for condensate heat recovery of the present invention mainly consists of a drying room, a dehumidification and reheating heat pump system, a heat recovery heat pump system coupled with condensate, and a heat exhaust and cooling heat pump storage system.

[0055] By collecting the condensate generated during dehumidification in the heat pump drying system and coupling it with a heat recovery system, the heat in the medium-temperature condensate is fully absorbed and high-temperature hot air is generated. This achieves heat recovery in the heat pump drying system, increases the heat and temperature of the supplied air, and improves the overall drying effect and energy efficiency of the system.

[0056] Example 2

[0057] In a preferred embodiment 2 of the present invention, a heat pump drying system control method is provided, which is applied to the heat pump drying system in the above embodiment 1.

[0058] Specifically Figure 3 An optional flowchart of the method is shown, such as Figure 3 As shown, the method includes the following steps S302-S306:

[0059] S302: Detect the air inlet temperature of the drying room and determine whether the air inlet temperature has reached the preset temperature;

[0060] S304: If so, control the heat pump drying system to maintain its current operating state;

[0061] S306: Otherwise, control the heat recovery heat pump system to start and reheat the incoming air into the drying room.

[0062] In the above embodiments, to address heat waste in heat pump drying systems, a condensate heat recovery heat pump drying system is proposed. This system includes a dehumidification and reheat heat pump system, as well as a water collection device to collect condensate generated by the evaporator of the dehumidification and reheat heat pump system. To effectively utilize the collected condensate, a hot water storage tank is also provided to store the condensate, along with a heat recovery heat pump system. The water in the storage tank provides heat to the condenser, thereby reheating the incoming air into the drying chamber and increasing its temperature. By coupling the condensate heat recovery heat pump system, the heat from the dehumidified condensate is fully utilized, avoiding the problem of low reheat air temperature after dehumidification and cooling in the heat pump drying system. This increases the heat and temperature of the supplied air, significantly reducing energy waste and improving the overall energy efficiency and temperature control range of the heat pump drying system.

[0063] In a preferred embodiment of the present invention, controlling the start-up of the heat recovery heat pump system includes: controlling the start-up of the second compressor of the heat recovery heat pump system; adjusting the opening degree of the air valve to adjust the air flow rate through the second condenser, thereby adjusting the inlet air temperature of the drying chamber until the inlet air temperature reaches the preset temperature. By adjusting the proportional opening degree of the air valve, the air flow rate through the second condenser is adjusted, thereby determining the proportion of primary reheat and achieving air regulation before secondary reheat.

[0064] Preferably, the system further includes: detecting whether the drying chamber needs heat dissipation; if so, controlling the heat dissipation and cooling system to start; otherwise, controlling the heat pump drying system to maintain its current operating state. The heat dissipation and cooling system, using the principle of a heat pump, absorbs heat from the drying chamber when cooling is needed or when heat dissipation is required after drying, and transfers this heat to a hot water storage tank for subsequent reuse.

[0065] After the gaseous refrigerant enters the compressor through the compressor suction port, it is compressed into a high-pressure, high-temperature gaseous refrigerant and enters the first condenser 2. It heats the dehumidified and cooled air from the first evaporator 4 into dehumidified and cooled air at an even higher temperature and sends it into the drying room 5. At the same time, the refrigerant condenses into a high-pressure liquid refrigerant. After being throttled, depressurized, and cooled by the first throttling valve, it enters the first evaporator 4.

[0066] After throttling, the refrigerant absorbs heat from the high-humidity and high-temperature air drawn in from the drying chamber 5, forming a low-pressure gaseous refrigerant. The high-humidity and high-temperature air flows through the fin surface of the first evaporator 4 and releases heat, condensing to form a large amount of medium-temperature condensate, thus achieving cooling and dehumidification.

[0067] The low-pressure gaseous refrigerant is drawn back into the compressor for compression, and this process is repeated.

[0068] When the above-mentioned dehumidification and reheat heat pump system is running, the first evaporator 4 generates a large amount of medium-temperature condensate, which is collected in the water collection pan and stored in the hot water storage tank 7.

[0069] The low-pressure, low-temperature gaseous refrigerant from the second evaporator is drawn into the compressor and compressed to form a high-pressure, high-temperature gaseous refrigerant. It then enters the second condenser 9, where it reheats the air dehumidified by the first evaporator 4, causing the refrigerant to condense into a high-pressure liquid refrigerant. After passing through the second throttling valve to reduce pressure and temperature, it enters the second evaporator, where it absorbs heat from the condensate in the hot water storage tank 7, causing the refrigerant to evaporate into a low-pressure, low-temperature gaseous refrigerant. This process is repeated.

[0070] The system takes into account the insufficient heat of the condensate in the hot water storage tank 7 or the very little recoverable heat, such as when there is relatively little condensate or the temperature is low in the early stage of drying. It adds an air-side evaporator to absorb enough heat from the air. The flow rate can be distributed through the opening of the second throttle valve to achieve sufficient reheat.

[0071] In the drying process, there are situations where the drying chamber 5 needs to exhaust heat or cool down. In this case, the heat pump principle is fully utilized to absorb the heat in the drying chamber 5 and transfer it to the hot water storage tank 7. The specific process is as follows:

[0072] The low-pressure gaseous refrigerant from the third evaporator 17 is drawn into the third compressor 14, where it is compressed into a high-pressure, high-temperature gaseous refrigerant. It then enters the third condenser 15 to release heat to the water in the hot water storage tank 7, condensing into a high-pressure liquid refrigerant. After being throttled, its pressure and temperature are reduced, and it enters the third evaporator 17 to absorb heat from the medium- and high-temperature air in the drying chamber 5 and cool it down. At the same time, the refrigerant evaporates into a low-pressure gaseous refrigerant and enters the compressor again, repeating this process.

[0073] The heat pump drying system for condensate heat recovery of the present invention mainly consists of a drying room, a dehumidification and reheating heat pump system, a heat recovery heat pump system coupled with condensate, and a heat exhaust and cooling heat pump storage system.

[0074] By collecting the condensate generated during dehumidification in the heat pump drying system and coupling it with a heat recovery system, the heat in the medium-temperature condensate is fully absorbed and high-temperature hot air is generated. This achieves heat recovery in the heat pump drying system, increases the heat and temperature of the supplied air, and improves the overall drying effect and energy efficiency of the system.

[0075] Example 3

[0076] Based on the heat pump drying system control method provided in Embodiment 2 above, in a preferred embodiment 3 of the present invention, a storage medium containing computer-executable instructions is also provided, which, when executed by a computer processor, are used to execute the heat pump drying system control method as described above.

[0077] In the above embodiments, to address heat waste in heat pump drying systems, a condensate heat recovery heat pump drying system is proposed. This system includes a dehumidification and reheat heat pump system, as well as a water collection device to collect condensate generated by the evaporator of the dehumidification and reheat heat pump system. To effectively utilize the collected condensate, a hot water storage tank is also provided to store the condensate, along with a heat recovery heat pump system. The water in the storage tank provides heat to the condenser, thereby reheating the incoming air into the drying chamber and increasing its temperature. By coupling the condensate heat recovery heat pump system, the heat from the dehumidified condensate is fully utilized, avoiding the problem of low reheat air temperature after dehumidification and cooling in the heat pump drying system. This increases the heat and temperature of the supplied air, significantly reducing energy waste and improving the overall energy efficiency and temperature control range of the heat pump drying system.

[0078] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0079] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0080] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0081] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0082] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0083] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0084] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not invented by the invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0085] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A heat pump drying system, characterized in that, The heat pump drying system, used in drying rooms, includes: A dehumidification and reheat heat pump system includes: a first compressor, a first condenser, a first throttling device, and a first evaporator connected in sequence; wherein, the first evaporator is connected to the return air inlet of the drying room and is used to condense the return air of the drying room, reduce the humidity of the return air, and then introduce it into the air inlet of the drying room; the first condenser is connected to the air inlet of the drying room and is used to heat the air entering the drying room. A hot water storage tank, located below the first evaporator, is used to store the condensate produced by the first evaporator; A heat recovery heat pump system includes: a second compressor, a second condenser, a second throttling device, and a second evaporator connected in sequence; wherein, the second evaporator is connected to the hot water storage tank and is used to provide heat to the second condenser using water from the hot water storage tank; the second condenser is located on the air supply duct from the first evaporator to the first condenser and is used to perform secondary heating on the return air entering the first condenser. An air valve, located on the air supply duct from the first evaporator to the first condenser, is used to adjust the ratio of return air directly entering the first condenser and flowing through the second condenser, thereby adjusting the inlet air temperature of the drying chamber.

2. The heat pump drying system according to claim 1, characterized in that, Also includes: The heat dissipation and cooling system is connected at one end to the heat dissipation outlet of the drying room and at the other end to the hot water storage tank. It is used to absorb the heat from the gas discharged from the heat dissipation outlet and heat the water in the hot water storage tank.

3. The heat pump drying system according to claim 2, characterized in that, The heat dissipation and cooling system includes: A third compressor, a third condenser, a third throttling device, and a third evaporator are connected in sequence; wherein, the third evaporator is located at the heat exhaust outlet of the drying chamber, and the third condenser is connected to the hot water storage tank for heating the water in the hot water storage tank using the heat from the third condenser.

4. The heat pump drying system according to claim 2, characterized in that, The heat dissipation and cooling system includes: A gas-water heat exchanger is located at the heat exhaust outlet of the drying chamber. The gas-water heat exchanger is connected to the hot water storage tank and is used to absorb the heat from the gas at the heat exhaust outlet to heat the water in the hot water storage tank.

5. The heat pump drying system according to claim 2, characterized in that, The second evaporator includes a first sub-evaporator and a second sub-evaporator arranged in parallel. The first sub-evaporator is an air-side evaporator, and the second sub-evaporator is a water-side evaporator. The second sub-evaporator is connected to the hot water storage tank, and a first water pump is installed on the pipeline connecting the second sub-evaporator and the hot water storage tank. A second water pump is installed on the pipeline connecting the heat dissipation and cooling system to the hot water storage tank.

6. A control method for a heat pump drying system, applied to a heat pump drying system as described in any one of claims 1 to 5, characterized in that, The method includes: Detect the air inlet temperature of the drying room and determine whether the air inlet temperature has reached the preset temperature; If so, control the heat pump drying system to maintain its current operating state; Otherwise, the heat recovery heat pump system is turned on to reheat the incoming air entering the drying room.

7. The method according to claim 6, characterized in that, The control of the heat recovery heat pump system to start includes: The second compressor of the heat recovery heat pump system is turned on. Adjust the opening of the air valve to regulate the airflow through the second condenser, thereby regulating the inlet air temperature of the drying chamber until the inlet air temperature reaches the preset temperature.

8. The method according to claim 6, characterized in that, Also includes: Check whether the drying room needs heat exhaust; If so, control the heat dissipation and cooling system to start; otherwise, control the heat pump drying system to maintain its current operating state.

9. A storage medium containing computer-executable instructions, characterized in that, The computer-executable instructions, when executed by a computer processor, are used to perform the heat pump drying system control method as described in any one of claims 6 to 8.

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