Heat pump drying system and control method thereof

Abstract

The invention discloses a heat pump drying system and a control method thereof, and the heat pump drying system comprises a dehumidification reheating heat pump system, a heat pump system and a control system, the heat storage water tank is located below the first evaporator and used for storing condensate water generated by the first evaporator; the heat recovery heat pump system comprises a second compressor, a second condenser, a second throttling device and a second evaporator which are connected in sequence; the second evaporator is connected with the heat storage water tank and used for providing heat for the second condenser through water in the heat storage water tank. The second condenser communicates with the air inlet of the drying room and is used for conducting secondary heating on the inlet air entering the drying room. The problems that in the prior art, condensate water in a heat pump drying system is not effectively utilized, and heat is wasted are solved, dehumidification condensate water heat is fully utilized, the air supply temperature is increased, the whole machine energy saving performance of the heat pump drying system is improved, and the temperature regulation and control range of the drying process is widened.

Description

Technical Field

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

[0002] Heat pump drying system is widely used in crops, fruits and vegetables, sludge and other industrial and agricultural applications. It uses the principle of high-temperature heat pump to increase the temperature in the drying / baking room and remove moisture from the dried products. During the dehumidification process, the evaporator of the heat pump will condense to produce a large amount of condensed water, and the temperature of the condensed water in the heat pump drying system is relatively high, generally above 30℃~40℃ or even higher. Direct discharge of this part of heat will cause a lot of heat waste.

[0003] Patent No. 202010924128.2 discloses a heat pump drying system, but the system mainly relies on opening the bypass air duct to introduce part of the hot and humid air in the drying room into the condenser, merge it with the dehumidified air after cooling from the evaporator for reheating, and then send the high-temperature hot air to the drying room. The patent's humid air heat bypass solution solves the problem of low air output to a certain extent, but the return air temperature in the drying room is low, the air humidity is increased after confluence, the air temperature increase after reheating is limited, and the hot air humidity sent to the drying room is relatively high. The overall drying effect will be discounted, and the heat carried by the condensed water is not well utilized, resulting in waste.

[0004] With regard to the problem that condensed water in the heat pump drying system in the related art is not effectively utilized and heat is wasted, no effective solution has been proposed so far. Summary of the invention

[0005] The present invention provides a heat pump drying system and a control method thereof, so as to at least solve the problem in the prior art that condensed water in the heat pump drying system is not effectively utilized and heat is wasted.

[0006] To solve the above technical problems, according to one aspect of an embodiment of the present invention, a heat pump drying system is provided, which is applied to a drying room, and the heat pump drying system includes: a dehumidification and reheat heat pump system, including: 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 outlet of the drying room, and is used to condense the return air of the drying room, and reduce the humidity of the return air before passing 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 incoming air entering the drying room; a heat storage tank is located below the first evaporator, and is used to store condensed water generated 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 heat storage tank, and is used to use the water in the heat storage tank to provide heat for the second condenser; 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.

[0007] Furthermore, it also includes: an air valve, located on the air supply duct from the first evaporator to the first condenser, for adjusting 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 room.

[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 is connected to the hot water storage tank, which is used to absorb the heat of the gas exhausted from the heat exhaust outlet and heat the water in the hot water storage tank.

[0009] Furthermore, the heat exhaust 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 exhaust outlet of the drying room, and the third condenser is connected to the hot water storage tank, and is used to use the heat of the third condenser to heat the water in the hot water storage tank.

[0010] Furthermore, the heat exhaust and cooling system includes: an air-water heat exchanger located at the heat exhaust outlet of the drying room, the air-water heat exchanger is connected to the heat storage tank, and is used to absorb the heat of the heat exhaust outlet gas to heat the water in the heat 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, 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 arranged on the pipeline connecting the second sub-evaporator and the hot water storage tank; a second water pump is arranged on the pipeline connecting the heat exhaust and cooling system and the hot water storage tank.

[0012] According to another aspect of an embodiment of the present invention, a heat pump drying system control method is provided, which is applied to a heat pump drying system such as the above-mentioned one, and the method includes: detecting the inlet air temperature of the drying room, and determining whether the inlet air temperature reaches a preset temperature; if so, controlling the heat pump drying system to maintain the current operating state; otherwise, controlling the heat recovery heat pump system to start, and performing secondary heating on the inlet air entering the drying room.

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

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

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

[0016] In the present invention, a heat pump drying system for condensed water heat recovery is proposed to address the heat waste in the heat pump drying system. In addition to the dehumidification and reheating heat pump system, the system also includes a water collection device for collecting condensed water generated by the evaporator of the dehumidification and reheating heat pump system. In order to effectively utilize the collected condensed water, a heat storage tank is provided to store the condensed water, and a heat recovery heat pump system is provided. The water in the heat storage tank is used to provide heat to its condenser to perform secondary heating on the incoming air entering the drying room, thereby increasing the incoming air temperature of the drying room. By coupling the heat pump system for condensed water heat recovery, the heat of the dehumidified condensed water is fully utilized, and the problem of low reheating air supply temperature after dehumidification and cooling of the heat pump drying system is avoided. The heat and temperature of the air supply are increased, energy waste is greatly reduced, and the heating temperature is increased, thereby improving the overall energy saving of the heat pump drying system and the temperature control range of the drying process. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0020] Description of reference numerals:

[0021] 1. The first compressor; 2. The first condenser; 3. The first throttling device; 4. The first evaporator; 5. The drying room; 6. The water collecting device; 7. The heat storage tank; 8. The second compressor; 9. The second condenser; 10. The second throttling device; 11. The first sub-evaporator; 12. The second sub-evaporator; 13. The air valve; 14. The third compressor; 15. The third condenser; 16. The third throttling device; 17. The third evaporator; 18. The air-water heat exchanger; 19. The second water pump; 20. The first water pump. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0024] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in 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] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0027] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0028] The optional embodiments of the present invention are described in detail below 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 An optional structural schematic diagram of the heat pump drying system is shown in FIG. Figure 1 As shown, the heat pump drying system includes:

[0032] The dehumidification and reheating heat pump system comprises: a first compressor 1, a first condenser 2, a first throttling device 3 and a first evaporator 4 which are connected in sequence; wherein the first evaporator 4 is connected to the return air port of the drying room 5, and is used to condense the return air of the drying room 5, reduce the humidity of the return air and then pass it into the air inlet of the drying room 5; the first condenser 2 is connected to the air inlet of the drying room 5, and is used to heat the air entering the drying room 5; when the dehumidification and reheating heat pump system is working, the air extracted from the drying room 5 is dehumidified to generate a large amount of condensed water, and the dehumidified air is reheated and then sent to the drying room 5; the first condenser 2 and the first evaporator 4 are located in two separate chambers, such as Figure 1 As shown, avoid mixing of return air and incoming air, which reduces the air intake effect;

[0033] The water collecting device 6 is located below the first evaporator 4 and is used to collect the condensed water generated by the first evaporator 4. The water collecting device 6 can be a water collecting tray or other water collecting forms, as long as it can collect the condensed water and prevent the condensed water from leaking.

[0034] A hot water storage tank 7, the water inlet of the hot water storage tank 7 is connected to the water outlet of the water collecting device 6, and is used to store condensed water;

[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 the hot water storage tank 7, and is used to use the water in the hot water storage tank 7 to provide heat for the second condenser 9; the second condenser 9 is connected to the air inlet of the drying room 5, and is used to perform secondary heating on the air entering the drying room 5. Figure 1 As shown, the hot water storage tank 7 exchanges heat with the second evaporator through the water circuit to increase the temperature of the second evaporator, thereby providing a higher temperature refrigerant for the second condenser 9, improving the heat exchange effect of the second condenser 9, and increasing the inlet air temperature. That is, the heat recovery heat pump system makes full use of the heat in the condensed water to reheat the dehumidified and cooled air once, and then supplies it to the conventional dehumidification and reheating heat pump for secondary reheating, thereby increasing the heat and temperature of the air supply.

[0036] In the above embodiment, a heat pump drying system for condensed water heat recovery is proposed to address the heat waste in the heat pump drying system. In addition to the dehumidification and reheating heat pump system, the system also includes a water collection device for collecting condensed water generated by the evaporator of the dehumidification and reheating heat pump system. In order to effectively utilize the collected condensed water, a heat storage tank is provided to store the condensed water, and a heat recovery heat pump system is provided. The water in the heat storage tank is used to provide heat to its condenser to perform secondary heating on the incoming air entering the drying room, thereby increasing the incoming air temperature of the drying room. By coupling the heat pump system for condensed water heat recovery, the heat of the dehumidified condensed water is fully utilized, and the problem of low reheating air supply temperature after dehumidification and cooling of the heat pump drying system is avoided. The heat and temperature of the air supply are increased, energy waste is greatly reduced, and the heating temperature is increased, thereby improving the energy saving of the heat pump drying system as a whole and the temperature control range of the drying process.

[0037] like Figure 1 As shown, the system further includes: an air valve 13, located on the air supply duct from the first evaporator 4 to the first condenser 2, for adjusting the ratio of the return air directly entering the first condenser 2 and flowing through the second condenser 9, thereby adjusting the air inlet temperature of the drying room 5. By adjusting the proportional opening size of the air valve 13, the air flow rate flowing through the second condenser 9 is adjusted, and then the ratio of the primary reheating heat is determined, so as to realize the temperature control of the air before the secondary reheating.

[0038] In order to further improve the energy utilization rate, the system also includes: a heat exhaust and cooling system, one end of which is connected to the heat exhaust outlet of the drying room 5 and the other end is connected to the hot water storage tank 7, which is used to absorb the heat of the gas exhausted from the heat exhaust outlet and heat the water in the hot water storage tank 7. When the drying room 5 needs to be cooled down or the heat needs to be discharged after drying, the heat exhaust and cooling system uses the heat pump principle to absorb the heat in the drying room 5 and transfer this part of the heat to the hot water storage tank 7 for subsequent reuse.

[0039] Alternatively, if Figure 1 As shown, the heat exhaust 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; wherein the third evaporator 17 is located at the heat exhaust outlet of the drying room 5, and the third condenser 15 is connected to the hot water storage tank 7, and is used to use the heat of the third condenser 15 to heat the water in the hot water storage tank 7. The use of a heat pump system can efficiently collect and utilize heat and improve energy utilization.

[0040] Figure 2 FIG. 4 shows another optional implementation of the heat removal and cooling system, such as Figure 2 As shown, the heat exhaust and cooling system includes: an air-water heat exchanger 18, which is located at the heat exhaust outlet of the drying room 5, and the air-water heat exchanger 18 is connected to the hot water storage tank 7, and is used to absorb the heat of the gas at the heat exhaust outlet and heat the water in the hot water storage tank 7. The heat exhaust and cooling heat pump heat storage system can be realized by an air-water heat exchanger. Although its cooling speed is lower than that of the heat pump system, it does not require additional energy consumption, which is conducive to improving the energy efficiency of the overall system.

[0041] like Figure 1 As shown, the second evaporator includes a first sub-evaporator 11 and a second sub-evaporator 12 which are arranged in parallel, the first sub-evaporator 11 is an air-side evaporator, 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 arranged on the pipeline connecting the second sub-evaporator 12 and the hot water storage tank 7; a second water pump 19 is arranged on the pipeline connecting the heat exhaust and cooling system and the hot water storage tank 7. The water pump can speed up the circulation of the water circuit, increase the water flow, and thus improve the heat exchange effect.

[0042] Below Figure 1 Take the heat pump drying system as an example to explain the specific working process of the 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 high-pressure and 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 higher-temperature air and sends it to the drying room 5. The refrigerant is condensed into high-pressure liquid refrigerant at the same time. It enters the first evaporator 4 after being throttled, depressurized and cooled by the first throttle valve.

[0045] After throttling, the refrigerant absorbs the heat of the high-humidity and high-temperature air sucked from the drying room 5 to form a low-pressure gaseous refrigerant. The high-humidity and high-temperature air flows through the fin surface of the first evaporator 4 to release heat, condensing to form a large amount of medium-temperature condensed water, thereby achieving cooling and dehumidification.

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

[0047] (2) Coupled condensate water heat recovery heat pump system

[0048] When the above-mentioned (1) dehumidification and reheating heat pump system is in operation, the first evaporator 4 generates a large amount of medium-temperature condensed water, which is collected by the water collecting pan and stored in the hot water storage tank 7.

[0049] The low-pressure and low-temperature gaseous refrigerant coming out of the second evaporator is sucked into the compressor and compressed to form a high-pressure and high-temperature gaseous refrigerant, which enters the second condenser 9 to reheat the air after dehumidification in the first evaporator 4, and the refrigerant is condensed into a high-pressure liquid refrigerant; it is then throttled, reduced in pressure and temperature by the second throttle valve and enters the second evaporator to absorb the heat of the condensed water in the hot water storage tank 7, and the refrigerant evaporates into a low-pressure and low-temperature gaseous refrigerant, which enters the compressor again, and this process is repeated.

[0050] The system takes into account that when the condensed water in the heat storage tank 7 has insufficient heat or very little recoverable heat, for example, when the condensed water is relatively small or the temperature is low in the early stage of drying, an evaporator is added on the air side to absorb enough heat from the air. The flow rate can be distributed through the opening of the second throttle valve to achieve sufficient primary reheating.

[0051] (3) Heat removal and cooling system

[0052] In the drying process, there is a situation where the drying room 5 needs to discharge heat or cool down. At this time, the heat pump principle is fully utilized to absorb the heat in the drying room 5 and transfer it to the hot water storage tank 7. The specific process is as follows:

[0053] The low-pressure gaseous refrigerant coming out of the third evaporator 17 is sucked into the third compressor 14, and after being compressed into a high-pressure and high-temperature gaseous refrigerant, it enters the third condenser 15 to release heat to the water in the hot water storage tank 7, and is condensed into a high-pressure liquid refrigerant. After throttling, reducing pressure and cooling, it enters the third evaporator 17, absorbs the heat of the medium and high temperature air in the drying room 5, and cools it. At the same time, the refrigerant evaporates into a low-pressure gaseous refrigerant and enters the compressor again, and this process is repeated.

[0054] The heat pump drying system for condensed water heat recovery of the present invention is mainly composed of a drying room, a dehumidification and reheating heat pump system, a heat recovery heat pump system coupled with condensed water, a heat exhaust and cooling heat pump heat storage system, etc.

[0055] By collecting the condensed water produced by dehumidification in the heat pump drying system, the heat in the medium-temperature condensed water is fully absorbed through the coupled heat recovery system to generate high-temperature hot air, thereby realizing heat recovery in the heat pump drying system, increasing the heat and temperature of the air supply, and improving the overall drying effect and energy saving 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-mentioned embodiment 1.

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

[0059] S302: Detecting the air inlet temperature of the drying room to determine whether the air inlet temperature reaches a preset temperature;

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

[0061] S306: Otherwise, the heat recovery heat pump system is controlled to start, and the incoming air entering the drying room is heated again.

[0062] In the above embodiment, a heat pump drying system for condensed water heat recovery is proposed to address the heat waste in the heat pump drying system. In addition to the dehumidification and reheating heat pump system, the system also includes a water collection device for collecting condensed water generated by the evaporator of the dehumidification and reheating heat pump system. In order to effectively utilize the collected condensed water, a heat storage tank is provided to store the condensed water, and a heat recovery heat pump system is provided. The water in the heat storage tank is used to provide heat to its condenser to perform secondary heating on the incoming air entering the drying room, thereby increasing the incoming air temperature of the drying room. By coupling the heat pump system for condensed water heat recovery, the heat of the dehumidified condensed water is fully utilized, and the problem of low reheating air supply temperature after dehumidification and cooling of the heat pump drying system is avoided. The heat and temperature of the air supply are increased, energy waste is greatly reduced, and the heating temperature is increased, thereby improving the energy saving of the heat pump drying system as a whole and the temperature control range of the drying process.

[0063] In a preferred embodiment of the present invention, controlling the heat recovery heat pump system to start 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 a preset temperature. By adjusting the proportional opening of the air valve, the air flow through the second condenser is adjusted, and the proportion of the primary reheating heat is determined to achieve air regulation before the secondary reheating.

[0064] Preferably, it also includes: detecting whether the drying room needs to discharge heat; if so, controlling the heat discharge and cooling system to start, otherwise, controlling the heat pump drying system to maintain the current operating state. When the drying room needs to be cooled down or heat needs to be discharged after drying, the heat discharge and cooling system uses the heat pump principle to absorb the heat in the drying room and transfer this part of the heat to the hot water storage tank for subsequent reuse.

[0065] After the gaseous refrigerant enters the compressor through the compressor suction port, it is compressed into high-pressure and 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 higher-temperature air and sends it to the drying room 5. The refrigerant is condensed into high-pressure liquid refrigerant at the same time. It enters the first evaporator 4 after being throttled, depressurized and cooled by the first throttle valve.

[0066] After throttling, the refrigerant absorbs the heat of the high-humidity and high-temperature air sucked from the drying room 5 to form a low-pressure gaseous refrigerant. The high-humidity and high-temperature air flows through the fin surface of the first evaporator 4 to release heat, condensing to form a large amount of medium-temperature condensed water, thereby achieving cooling and dehumidification.

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

[0068] When the dehumidification and reheating heat pump system is in operation, the first evaporator 4 generates a large amount of medium-temperature condensed water, which is collected by the water collecting pan and stored in the hot water storage tank 7 .

[0069] The low-pressure and low-temperature gaseous refrigerant coming out of the second evaporator is sucked into the compressor and compressed to form a high-pressure and high-temperature gaseous refrigerant, which enters the second condenser 9 to reheat the air after dehumidification in the first evaporator 4, and the refrigerant is condensed into a high-pressure liquid refrigerant; it is then throttled, reduced in pressure and temperature by the second throttle valve and enters the second evaporator to absorb the heat of the condensed water in the hot water storage tank 7, and the refrigerant evaporates into a low-pressure and low-temperature gaseous refrigerant, which enters the compressor again, and this process is repeated.

[0070] The system takes into account that when the condensed water in the heat storage tank 7 has insufficient heat or very little recoverable heat, for example, when the condensed water is relatively small or the temperature is low in the early stage of drying, an evaporator is added on the air side to absorb enough heat from the air. The flow rate can be distributed through the opening of the second throttle valve to achieve sufficient primary reheating.

[0071] In the drying process, there is a situation where the drying room 5 needs to discharge heat or cool down. At this time, the heat pump principle is fully utilized to absorb the heat in the drying room 5 and transfer it to the hot water storage tank 7. The specific process is as follows:

[0072] The low-pressure gaseous refrigerant coming out of the third evaporator 17 is sucked into the third compressor 14, and after being compressed into a high-pressure and high-temperature gaseous refrigerant, it enters the third condenser 15 to release heat to the water in the hot water storage tank 7, and is condensed into a high-pressure liquid refrigerant. After throttling, reducing pressure and cooling, it enters the third evaporator 17, absorbs the heat of the medium and high temperature air in the drying room 5, and cools it. At the same time, the refrigerant evaporates into a low-pressure gaseous refrigerant and enters the compressor again, and this process is repeated.

[0073] The heat pump drying system for condensed water heat recovery of the present invention is mainly composed of a drying room, a dehumidification and reheating heat pump system, a heat recovery heat pump system coupled with condensed water, a heat exhaust and cooling heat pump heat storage system, etc.

[0074] By collecting the condensed water produced by dehumidification in the heat pump drying system, the heat in the medium-temperature condensed water is fully absorbed through the coupled heat recovery system to generate high-temperature hot air, thereby realizing heat recovery in the heat pump drying system, increasing the heat and temperature of the air supply, and improving the overall drying effect and energy saving of the system.

[0075] Example 3

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

[0077] In the above embodiment, a heat pump drying system for condensed water heat recovery is proposed to address the heat waste in the heat pump drying system. In addition to the dehumidification and reheating heat pump system, the system also includes a water collection device for collecting condensed water generated by the evaporator of the dehumidification and reheating heat pump system. In order to effectively utilize the collected condensed water, a heat storage tank is provided to store the condensed water, and a heat recovery heat pump system is provided. The water in the heat storage tank is used to provide heat to its condenser to perform secondary heating on the incoming air entering the drying room, thereby increasing the incoming air temperature of the drying room. By coupling the heat pump system for condensed water heat recovery, the heat of the dehumidified condensed water is fully utilized, and the problem of low reheating air supply temperature after dehumidification and cooling of the heat pump drying system is avoided. The heat and temperature of the air supply are increased, energy waste is greatly reduced, and the heating temperature is increased, thereby improving the energy saving of the heat pump drying system as a whole and the temperature control range of the drying process.

[0078] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0079] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made 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. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

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

[0082] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0083] If the integrated unit is implemented in the form of 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, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

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

[0085] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A heat pump drying system, characterized in that: Applied to a drying room, the heat pump drying system comprises: The dehumidification and reheating heat pump system comprises: 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 port 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 pass 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, and used to store condensed water generated by the first evaporator; The heat recovery heat pump system comprises: 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 use the water in the hot water storage tank to provide heat for the second condenser; 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.

2. The heat pump drying system according to claim 1, characterized in that: Also includes: The air valve is located on the air supply duct from the first evaporator to the first condenser, and 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 room.

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

4. The heat pump drying system according to claim 3, characterized in that: The heat removal and cooling system comprises: 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 room, and the third condenser is connected to the heat storage tank to heat the water in the heat storage tank using the heat of the third condenser.

5. The heat pump drying system according to claim 3, characterized in that: The heat removal and cooling system comprises: The air-water heat exchanger is located at the heat exhaust outlet of the drying room. The air-water heat exchanger is connected to the heat storage tank and is used to absorb the heat of the gas at the heat exhaust outlet to heat the water in the heat storage tank.

6. The heat pump drying system according to claim 3, characterized in that: The second evaporator comprises a first sub-evaporator and a second sub-evaporator arranged in parallel, the first sub-evaporator is an air-side evaporator, 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 arranged on the pipeline connecting the second sub-evaporator and the hot water storage tank; A second water pump is provided on the pipeline connecting the heat exhaust and cooling system with the hot water storage tank.

7. A heat pump drying system control method, applied to the heat pump drying system according to any one of claims 1 to 6, characterized in that: The method comprises: Detecting the air inlet temperature of the drying room, and determining whether the air inlet temperature reaches a preset temperature; If yes, controlling the heat pump drying system to maintain the current operating state; Otherwise, the heat recovery heat pump system is controlled to start, and the incoming air entering the drying room is heated again.

8. The method according to claim 7, characterized in that The controlling the heat recovery heat pump system to start includes: Controlling the second compressor of the heat recovery heat pump system to start; The opening of the air valve is adjusted to adjust the air flow through the second condenser, thereby adjusting the inlet air temperature of the drying room until the inlet air temperature reaches the preset temperature.

9. The method according to claim 7, characterized in that: Also includes: Detecting whether the drying room needs to exhaust heat; If so, the heat exhaust and cooling system is controlled to start, otherwise, the heat pump drying system is controlled to maintain the current operating state.

10. A storage medium containing computer executable instructions, characterized in that: The computer executable instructions are used to execute the heat pump drying system control method according to any one of claims 7 to 9 when executed by a computer processor.

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