Heat pump clothes dryer and control method thereof

Abstract

The invention provides a heat pump clothes dryer and a control method thereof.The heat pump clothes dryer comprises a clothes containing cavity, an air duct, a second condenser and a heat dissipation mechanism, and the clothes containing cavity and the air duct are connected to form a circulating air path; the heat pump clothes dryer further comprises a refrigerant circulation loop formed by sequentially connecting a compression mechanism, a first condenser, a first throttling device and an evaporator, the evaporator and the first condenser are both arranged in the air duct, and the evaporator is located on the windward side of the first condenser. The second condenser is arranged on the refrigerant circulation loop and located on the outer side of the clothes containing cavity and the outer side of the air flue. The heat dissipation mechanism is used for conducting heat dissipation on the second condenser and can be opened or closed. At the last stage of drying, the heat dissipation mechanism can be started, the second condenser is put into use, and dissipation of part of heat is assisted, so that the temperature of the first condenser in the air duct can be reduced, the air outlet temperature of the clothes containing cavity is reduced, the evaporation temperature is reduced, and the dehumidification capacity of the system is improved.

Description

Technical Field

[0001] This invention belongs to the field of dryer technology, specifically relating to a heat pump dryer and its control method. Background Technology

[0002] With Chinese consumers' pursuit of a high-quality lifestyle, the demand for clothes dryers has grown rapidly in recent years, especially in southern my country and in rainy and humid climates. In some large northern cities, the demand for efficient and convenient modern living, particularly in limited living spaces and humid environments where traditional air-drying methods are inconvenient, has driven the growth of the clothes dryer market by providing a fast and hygienic solution. Traditional clothes dryers primarily use electric heating, but this method is energy-intensive, inefficient, and has high long-term operating costs. The high energy consumption and heat emissions do not align with the trend of energy conservation and environmental protection. Furthermore, the high drying temperatures can damage certain fabrics (such as silk, wool, and synthetic fibers), causing deformation, shrinkage, or fiber breakage. Therefore, they are gradually being replaced by more efficient heat pump drying technology.

[0003] Heat pump drying technology boasts low energy consumption and low noise. While its initial cost is relatively high, its long-term energy-saving benefits are significant, aligning with the call for "green appliances." Furthermore, the lower drying temperature of heat pumps effectively protects clothing and ensures even drying inside and out, avoiding the problem of "dry outside, damp inside," thus gaining increasing popularity among consumers. Sales of heat pump dryers are steadily increasing in emerging markets, and China is expected to become one of the world's largest heat pump dryer markets in the future.

[0004] However, in the later stages of heat pump dryers, most of the water in the clothes has already been extracted. The air temperature after heat and moisture exchange with the clothes is high and the moisture content is low. But heat pump dryers are closed-loop systems. At this time, the evaporation temperature of the heat pump system rises, which weakens the dehumidification capacity and makes it more difficult for the moisture in the clothes to be extracted. At the same time, the condensation temperature and exhaust temperature gradually rise, and the exhaust temperature is limited and reduced, which further weakens the dehumidification capacity of the heat pump system. As a result, the water in the clothes is not easy to be extracted, resulting in low drying efficiency and long drying time. This is especially inconvenient for users when dealing with large quantities or heavy clothes. Summary of the Invention

[0005] Therefore, the present invention provides a heat pump dryer and its control method, which can solve the technical problem of decreased dehumidification capacity of heat pump dryers at the end of the heat pump drying process in the prior art.

[0006] To address the aforementioned problems, this invention provides a heat pump dryer, comprising a clothes-containing cavity and an air duct. The air outlet of the air duct is connected to the air inlet of the clothes-containing cavity, and the air outlet of the clothes-containing cavity is also connected to the air inlet of the air duct. The heat pump dryer further includes a refrigerant circulation loop formed by sequentially connecting a compression mechanism, a first condenser, a first throttling device, and an evaporator. Both the evaporator and the first condenser are disposed within the air duct, and the evaporator is located on the upwind side of the first condenser.

[0007] The heat pump dryer further includes a second condenser and a heat dissipation mechanism. The second condenser is disposed on the refrigerant circulation loop and located outside both the clothes receiving cavity and the air duct. The heat dissipation mechanism is used to dissipate heat from the second condenser and can be turned on or off.

[0008] In some embodiments, the heat dissipation mechanism includes a heat dissipation fan, which dissipates heat from the second condenser.

[0009] In some embodiments, the heat pump dryer also includes a controller;

[0010] The controller is configured to activate the heat dissipation mechanism when the exhaust temperature of the compression mechanism is greater than or equal to a first preset value and the temperature of the first condenser is greater than or equal to a second preset value; the controller is also configured to deactivate the heat dissipation mechanism when the exhaust temperature of the compression mechanism is less than the first preset value and / or the temperature of the first condenser is less than the second preset value.

[0011] In some embodiments, the evaporator includes a first evaporator and a second evaporator, the first evaporator being located on the upwind side of the second evaporator, and the compression mechanism including a first compression chamber and a second compression chamber that are independent of each other. The exhaust ports of both the first compression chamber and the second compression chamber are connected to the refrigerant inlet of the first condenser. One end of both the first evaporator and the second evaporator is connected to the end of the first throttling device opposite to the first condenser, and the other end of the first evaporator is connected to the intake port of the first compression chamber, and the other end of the second evaporator is connected to the intake port of the second compression chamber.

[0012] In some embodiments, one end of both the first evaporator and the second evaporator is connected to the end of the first throttling device away from the first condenser via a gas-liquid separator; the gas-liquid separator has an inlet, a liquid outlet, and a gas outlet, the gas-liquid separator being connected to the end of the first throttling device away from the first condenser via the inlet, and connected to one end of both the first evaporator and the second evaporator via the liquid outlet; wherein,

[0013] The second compression chamber has an A air inlet, which is connected to the gas outlet of the gas-liquid separator.

[0014] In some embodiments, the compression mechanism includes a compressor, wherein the first compression chamber and the second compression chamber are two independent compression chambers of the same compressor; wherein the compressor further has a first partition separating the first compression chamber and the second compression chamber, the first partition being provided with a first gas supply channel, and the gas outlet of the gas-liquid separator being connected to the A gas supply port through the first gas supply channel.

[0015] In some embodiments, the first compression chamber has a B-type air inlet, which is connected to the gas outlet of the gas-liquid separator.

[0016] In some embodiments, the compression mechanism includes a compressor, and the first compression chamber and the second compression chamber are two independent compression chambers of the same compressor; wherein, the compressor further has a second partition separating the first compression chamber and the second compression chamber, and the second partition is provided with a second gas supply channel, and the gas outlet of the gas-liquid separator is connected to both the A gas supply port and the B gas supply port through the second gas supply channel.

[0017] In some embodiments, a second throttling device is provided on the pipeline between the first evaporator and the liquid outlet; and / or, a third throttling device is provided on the pipeline between the second evaporator and the liquid outlet.

[0018] In some embodiments, the first condenser and the second condenser are connected in series.

[0019] The present invention also provides a control method for any of the above-mentioned heat pump dryers, comprising the following steps:

[0020] Step S1: Determine whether the exhaust temperature of the compression mechanism is greater than or equal to a first preset value, and whether the temperature of the first condenser is greater than or equal to a second preset value;

[0021] Step S2: If the exhaust temperature of the compression mechanism is greater than or equal to the first preset value, and the temperature of the first condenser is greater than or equal to the second preset value, then the heat dissipation mechanism is turned on; if the exhaust temperature of the compression mechanism is less than the first preset value, and / or the temperature of the first condenser is less than the second preset value, then the heat dissipation mechanism is turned off.

[0022] The heat pump dryer and its control method provided by this invention have the following beneficial effects:

[0023] 1. The heat pump dryer of the present invention, by adding a second condenser, improves the drying rate. Initially, the air inlet temperature of the clothes-containing cavity needs to be rapidly increased, during which time the heat dissipation mechanism is not activated. Towards the end of the drying process, once the system's exhaust temperature and condensation temperature reach certain preset values, the heat dissipation mechanism is activated, putting the second condenser into operation to help dissipate some heat. This lowers the temperature of the first condenser inside the air duct, thereby reducing the exhaust temperature of the clothes-containing cavity and the evaporation temperature. Simultaneously, it reduces the impact of exhaust temperature limitations on the system, allowing for further increases in frequency and further reduction of the evaporation temperature, thus enhancing the system's dehumidification capacity.

[0024] 2. Since the use of the second condenser can reduce the temperature of the first condenser in the air duct, the system can still operate safely and stably under high frequency conditions. The system does not need to reduce the frequency to ensure its reliability, and prevents the system from reducing the frequency due to excessive exhaust temperature. This improves drying efficiency and shortens drying time.

[0025] 3. This invention employs a quasi-two-stage compression coupled with cascade heat exchange system circulation, fully leveraging the advantages of both the quasi-two-stage and dual-temperature systems. The quasi-two-stage system, through gas replenishment, lowers the exhaust temperature and evaporator inlet enthalpy, increasing the system's heat exchange capacity and significantly enhancing volumetric cooling capacity, thus improving system energy efficiency. The dual-temperature system achieves cascade cooling and dehumidification; the low-temperature evaporation temperature increases the system's dehumidification capacity, resulting in low moisture content in the evaporator outlet air. With the drum inlet air temperature remaining almost constant, reducing the moisture content in the drum inlet air facilitates the extraction of moisture from clothing, thereby shortening drying time. Attached Figure Description

[0026] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of a heat pump dryer under single air replenishment according to an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the structure of a heat pump dryer with dual air replenishment according to an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of a single-air-compression mechanism according to an embodiment of the present invention;

[0030] Figure 4 This is a structural schematic diagram of the first partition plate;

[0031] Figure 5 This is a schematic diagram of a dual-air-supply compression mechanism provided in an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of the second partition.

[0033] The attached figures are labeled as follows:

[0034] 1. First partition plate; 2. First air supply channel; 5. Evaporator; 7. Second air supply channel; 10. Compression mechanism; 11. Inlet of the first compression chamber; 12. Inlet of the second compression chamber; 13. Air supply port A; 14. Air supply port B; 15. Exhaust port of the first compression chamber; 16. Exhaust port of the second compression chamber; 20. First condenser; 21. First air inlet; 22. First air outlet; 31. First throttling device; 32. Second throttling device; 33. ... Three-stage throttling device; 40. Gas-liquid separator; 41. Inlet; 42. Liquid outlet; 43. Gas outlet; 51. First evaporator; 52. Second evaporator; 61. Another fan; 62. Cooling fan; 70. Second condenser; 71. Second air inlet; 72. Second A air outlet; 73. Second B air outlet; 74. Second partition plate; 80. Filter; 90. Air duct; 100. Clothing storage cavity; 1a. First compression chamber; 1b. Second compression chamber. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0037] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0038] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0039] See also Figure 1 As shown, according to an embodiment of the present invention, a heat pump dryer is provided, which includes a clothes receiving cavity 100 and an air duct 90. The air outlet of the air duct 90 is connected to the air inlet of the clothes receiving cavity 100, and the air outlet of the clothes receiving cavity 100 is connected to the air inlet of the air duct 90. The air duct 90 and the clothes receiving cavity 100 are connected to form a circulating air path.

[0040] The aforementioned heat pump dryer also includes a refrigerant circulation loop formed by sequentially connecting a compression mechanism 10, a first condenser 20, a first throttling device 31, and an evaporator 5. Both the evaporator 5 and the first condenser 20 are located within the air duct 90, with the evaporator 5 positioned upwind of the first condenser 20. The heat pump dryer further includes a second condenser 70 and a heat dissipation mechanism. The second condenser 70 is located on the refrigerant circulation loop, outside both the clothes-containing cavity 100 and the air duct 90. The heat dissipation mechanism is used to dissipate heat from the second condenser 70 and can be turned on or off.

[0041] In the above example, the heat pump dryer of the present invention adds a second condenser 70. To improve the drying rate, the inlet air temperature of the clothes-containing cavity 100 needs to be rapidly increased in the early stage of drying, during which time the heat dissipation mechanism is not activated. Towards the end of the drying process, after the system's exhaust temperature and condensation temperature reach certain preset values, the heat dissipation mechanism is activated, putting the second condenser 70 into use to help dissipate some heat. This reduces the temperature of the first condenser 20 inside the air duct 90, thereby lowering the outlet air temperature of the clothes-containing cavity 100, reducing the evaporation temperature, and minimizing the impact of exhaust temperature limitations on the system. This allows for further increases in frequency, further reduction of the evaporation temperature, and improved system dehumidification capacity.

[0042] In addition, the use of the second condenser 70 can reduce the temperature of the first condenser 20 in the air duct 90, thereby ensuring that the system can still operate safely and stably under high frequency conditions. The system does not need to reduce the frequency to ensure its reliability, and prevents the system from reducing the frequency due to excessive exhaust temperature, thereby improving drying efficiency and shortening drying time.

[0043] It's important to note that the basic principle of dehumidification is that when the air temperature drops below the dew point, water vapor condenses into liquid water (i.e., dehumidification). The dew point is the critical temperature at which water vapor begins to condense. Therefore, the evaporator surface temperature must be lower than the air's dew point temperature for effective dehumidification. If the evaporation temperature is too high, the air cannot be cooled below the dew point, water vapor cannot condense, and dehumidification capacity is weakened. Therefore, lowering the evaporator temperature at the end of the drying process helps improve the system's dehumidification capacity.

[0044] In some embodiments, the aforementioned heat pump dryer may have a drum, the interior of which forms the aforementioned clothing receiving cavity 100. The aforementioned first condenser 20 and second condenser 70 may be connected in series.

[0045] To achieve the function of the aforementioned heat dissipation mechanism, in some embodiments, such as Figure 1 As shown, the aforementioned heat dissipation mechanism may include a cooling fan 62, which dissipates heat from the second condenser 70. Specifically, the cooling fan 62 may be located at the second condenser 70, and the cooling fan 62 dissipates heat and cools the second condenser 70 by blowing air onto it.

[0046] In some embodiments, the aforementioned heat pump dryer may further include a controller. The controller is configured to activate the heat dissipation mechanism when the exhaust temperature of the compression mechanism 10 is greater than or equal to a first preset value and the temperature of the first condenser 20 is greater than or equal to a second preset value. The controller is also configured to deactivate the heat dissipation mechanism when the exhaust temperature of the compression mechanism 10 is less than the first preset value and / or the temperature of the first condenser 20 is less than the second preset value.

[0047] In the above example, during the initial stage of heat pump drying, the exhaust temperature of the compressor 10 is lower than the first preset value, and / or the temperature of the first condenser 20 is lower than the second preset value. To improve the drying rate, the drum inlet air temperature needs to be rapidly increased during the initial stage of drying. Therefore, the heat dissipation mechanism is closed, preventing the second condenser 70 from starting initially. During the final stage of heat pump drying, when the exhaust temperature of the compressor 10 is greater than or equal to the first preset value, and the temperature of the first condenser 20 is greater than or equal to the second preset value, the evaporator temperature becomes higher, leading to a weakened dehumidification capacity of the system and difficulty in removing moisture from the clothes. At this point, by activating the heat dissipation mechanism to cool the second condenser 70, the heat dissipation of the second condenser 70 is increased, thereby reducing the temperature of the first condenser 20 and lowering the outlet air temperature of the clothes-containing cavity 100. This, in turn, lowers the evaporation temperature and enhances the system's dehumidification capacity.

[0048] In some implementations, such as Figure 1 As shown, the aforementioned evaporator includes a first evaporator 51 and a second evaporator 52, with the first evaporator 51 located on the upwind side of the second evaporator 52. The aforementioned compression mechanism 10 includes a first compression chamber 1a and a second compression chamber 1b, which are independent of each other. The exhaust ports of both the first compression chamber 1a and the second compression chamber 1b are connected to the refrigerant inlet of the first condenser 20. One end of both the first evaporator 51 and the second evaporator 52 is connected to the end of the first throttling device 31 that is away from the first condenser 20. The other end of the first evaporator 51 is connected to the suction port 11 of the first compression chamber, and the other end of the second evaporator 52 is connected to the suction port 12 of the second compression chamber.

[0049] Since the first evaporator 51 is located upwind of the second evaporator 52, it exchanges heat with air exiting the clothing storage cavity 100. At this point, the air temperature is high, resulting in a high temperature for the first evaporator 51. After exchanging heat with the first evaporator 51, the air temperature decreases (the first evaporator 51 absorbs heat), and then it exchanges heat with the second evaporator 52, thus resulting in a lower temperature for the second evaporator 52. The second evaporator 52 can also be referred to as a low-temperature evaporator.

[0050] Because the first evaporator 51 and the second evaporator 52 have different evaporation temperatures, each is used in conjunction with a compression chamber. The first compression chamber 1a, because it is used in conjunction with the first evaporator 51, is sometimes referred to as a high-temperature evaporator, and the first compression chamber 1a is called a high-temperature compression chamber. The second compression chamber 1b, because it is used in conjunction with the second evaporator 52, is sometimes referred to as a low-temperature evaporator, and the second compression chamber 1b is called a low-temperature compression chamber.

[0051] The first compression chamber 1a and the second compression chamber 1b are almost identical in structure, but their volumes are different, their volume ratios are different, and their energy efficiencies also differ to some extent.

[0052] In the above example, the first compression chamber 1a, in conjunction with the first evaporator 51, and the second compression chamber 1b, in conjunction with the second evaporator 52, form a dual-temperature system with two evaporation temperatures. The combined operation of the first evaporator 51 and the second evaporator 52 achieves tiered cooling and dehumidification. The lower temperature of the second evaporator 52 increases the system's dehumidification capacity and results in lower moisture content in the outlet air. With the inlet air temperature of the clothing storage chamber 100 remaining almost constant, the moisture content of the inlet air can be reduced, facilitating the leaching of moisture from the clothing and thus shortening the drying time.

[0053] In some implementations, such as Figure 1 As shown, one end of both the first evaporator 51 and the second evaporator 52 is connected to the end of the first throttling device 31 away from the first condenser 20 via a gas-liquid separator 40. The gas-liquid separator 40 has an inlet 41, a liquid outlet 42, and a gas outlet 43. The gas-liquid separator 40 is connected to the end of the first throttling device 31 away from the first condenser 20 via the inlet 41, and the gas-liquid separator 40 is connected to one end of both the first evaporator 51 and the second evaporator 52 via the liquid outlet 42. The second compression chamber 1b has an A-type gas inlet 13, which is connected to the gas outlet 43 of the gas-liquid separator 40.

[0054] In the example above, by supplementing the second compression chamber 1b with gas to increase enthalpy, the exhaust temperature can be reduced, the evaporator inlet specific enthalpy can be reduced, the heat exchange capacity of the system can be increased, the volumetric cooling capacity can be significantly increased, the pressure ratio can be reduced, and the system energy efficiency can be improved.

[0055] In some embodiments, the aforementioned gas-liquid separator 40 may be a flash evaporator or the like.

[0056] In order to replenish the second compression chamber 1b as described above, in one example, such as Figure 1 As shown, the aforementioned compression mechanism 10 may include a compressor, and the aforementioned first compression chamber 1a and second compression chamber 1b are two independent compression chambers of the same compressor. Wherein, as Figure 3-4As shown, the compressor also has a first partition 1 separating the first compression chamber 1a and the second compression chamber 1b. The first partition 1 has a first gas supply channel 2, and the gas outlet 43 of the gas-liquid separator 40 is connected to the gas supply port A 13 through the first gas supply channel 2. The first gas supply channel 2 has a first inlet 21 and a first outlet 22. The first gas supply channel 2 is connected to the gas outlet 43 of the gas-liquid separator 40 through the first inlet 21, and to the gas supply port A 13 through the first outlet 22. In this example, the compressor can be a dual-suction, single-row, single-gas supply compressor. The specific structure of this dual-suction, single-row, single-gas supply compressor is existing technology and will not be described in detail here.

[0057] In some implementations, such as Figure 2 As shown, the aforementioned first compression chamber 1a may have a B air inlet 14, which is connected to the gas outlet 43 of the gas-liquid separator 40.

[0058] In the above example, by supplementing gas to both the first compression chamber 1a and the second compression chamber 1b to increase enthalpy, the exhaust temperature can be further reduced, the evaporator inlet specific enthalpy can be reduced, the heat exchange capacity of the system can be increased, the volumetric cooling capacity can be significantly increased, the pressure ratio can be reduced, and the system energy efficiency can be improved.

[0059] In order to replenish air to both the first compression chamber 1a and the second compression chamber 1b, in one example, such as Figure 2 As shown, the aforementioned compression mechanism 10 includes a compressor, and the aforementioned first compression chamber 1a and second compression chamber 1b are two independent compression chambers of the same compressor. Wherein, as Figure 5-6 As shown, the compressor also has a second partition 74 separating the first compression chamber 1a and the second compression chamber 1b. The second partition 74 is provided with a second gas supply channel 7, through which the gas outlet 43 of the gas-liquid separator 40 is connected to both gas supply port A 13 and gas supply port B 14. The second gas supply channel 7 has a second inlet 71, a second outlet A 72, and a second outlet B 73. The second gas supply channel 7 is connected to the gas outlet 43 of the gas-liquid separator 40 through the second inlet 71, and to gas supply port A 13 through the second outlet A 72, and to gas supply port B 14 through the second outlet B 73. In this example, the compressor can be a dual-suction, single-row, dual-gas-supply compressor. The specific structure of this dual-suction, single-row, dual-gas-supply compressor is prior art and will not be described in detail here.

[0060] In some implementations, such as Figure 1 As shown, a second throttling device 32 may be provided on the pipeline between the aforementioned first evaporator 51 and the liquid outlet 42. And / or, a third throttling device 33 may be provided on the pipeline between the second evaporator 52 and the liquid outlet 42.

[0061] It should be noted that the first throttling device 31, the second throttling device 32, and the third throttling device 33 mentioned above are all throttling valves, such as electronic expansion valves. In one example, the aforementioned compression mechanism 10 may include a first compressor and a second compressor that are independent of each other. The first compressor has the aforementioned first compression chamber 1a, and the second compressor has the aforementioned second compression chamber 1b.

[0062] In some implementations, such as Figure 1 As shown, the aforementioned heat pump dryer also includes another fan 61, which is disposed within the air duct 90 to drive airflow within the air duct 90. This other fan 61 can be disposed on the upper side of the aforementioned evaporator. When the evaporator includes a first evaporator 51 and a second evaporator 52, the other fan 61 is located on the side of the first evaporator 51 facing away from the second evaporator 52.

[0063] like Figure 1 As shown, the aforementioned heat pump dryer also includes a filter 80, which is disposed within the air duct 90 and located on the upwind side of the evaporator to filter the air flowing into the evaporator. Preferably, the filter 80 is located on the upwind side of the aforementioned other fan 61.

[0064] In some embodiments, the present invention also provides a control method for any of the above-mentioned heat pump dryers, comprising the following steps:

[0065] Step S1: Determine whether the exhaust temperature of the compression mechanism 10 is greater than or equal to the first preset value, and whether the temperature of the first condenser 20 is greater than or equal to the second preset value.

[0066] Step S2: If the exhaust temperature of the compression mechanism 10 is greater than or equal to the first preset value, and the temperature of the first condenser 20 is greater than or equal to the second preset value, then the heat dissipation mechanism is turned on; if the exhaust temperature of the compression mechanism 10 is less than the first preset value, and / or the temperature of the first condenser 20 is less than the second preset value, then the heat dissipation mechanism is turned off.

[0067] In the above example, during the initial stage of heat pump drying, the exhaust temperature of the compressor 10 is lower than the first preset value, and / or the temperature of the first condenser 20 is lower than the second preset value. To improve the drying rate, the drum inlet air temperature needs to be rapidly increased during the initial stage of drying. Therefore, the heat dissipation mechanism is closed, preventing the second condenser 70 from starting initially. During the final stage of heat pump drying, when the exhaust temperature of the compressor 10 is greater than or equal to the first preset value, and the temperature of the first condenser 20 is greater than or equal to the second preset value, the evaporator temperature becomes higher, leading to a weakened dehumidification capacity of the system and difficulty in removing moisture from the clothes. At this point, by activating the heat dissipation mechanism to cool the second condenser 70, the heat dissipation of the second condenser 70 is increased, thereby reducing the temperature of the first condenser 20 and lowering the outlet air temperature of the clothes-containing cavity 100. This, in turn, lowers the evaporation temperature and enhances the system's dehumidification capacity.

[0068] It should be noted that when the compression mechanism 10 includes a first compression chamber 1a and a second compression chamber 1b that are independent of each other, the exhaust temperature of the aforementioned compression mechanism 10 refers to the temperature after the exhaust gases from the first compression chamber 1a and the second compression chamber 1b are mixed.

[0069] For ease of understanding, the overall structure of the present invention will be described below, and its working principle will be explained.

[0070] The heat pump dryer of the present invention includes a refrigerant-side circulation and an air-side circulation. The aforementioned refrigerant circulation loop forms the refrigerant-side circulation. The loop formed by connecting the aforementioned clothing storage cavity 100 and the air duct 90 forms the air-side circulation.

[0071] Refrigerant-side circulation: When the heat pump dryer starts running, the high-temperature, high-pressure gaseous refrigerant discharged from the compressor flows through the second condenser 70 and then enters the first condenser 20, where it exchanges heat with the air in the air duct 90. After releasing heat, it becomes a subcooled liquid refrigerant, which is then throttled and depressurized by the first throttling device 31, becoming a vapor-liquid two-phase state before entering the gas-liquid separator 40. When only the second compression chamber 1b has a gas inlet, the gaseous saturated refrigerant enters the A gas inlet 13 of the second compression chamber 1b in the gas-liquid separator 40. When both the first compression chamber 1a and the second compression chamber 1b have gas inlets, the gaseous saturated refrigerant will enter the A gas inlet 13 of the second compression chamber 1b and the B gas inlet 14 of the first compression chamber 1a, respectively.

[0072] The liquid saturated refrigerant is divided into two paths. One path is throttled and depressurized by the second throttling device 32 before entering the first evaporator 51. After heat exchange, it enters the suction port 11 of the first compression chamber 1a and, after compression, exits the first compression chamber at the discharge port 15. The other path is throttled and depressurized by the third throttling device 33 before entering the second evaporator 52. After heat exchange, it enters the suction port 12 of the second compression chamber and, after being compressed to an intermediate pressure, mixes with the refrigerant from the A replenishment port 13. The mixed refrigerant is further compressed by the second compression chamber 1b before exiting the second compression chamber at the discharge port 16. The refrigerants discharged from the first compression chamber at the discharge port 15 and the second compression chamber at the discharge port 16 are mixed and then discharged, thus completing the entire refrigerant side circulation.

[0073] Air-side circulation: Low-temperature, high-humidity air from the clothing storage cavity 100 passes through filter 80 and exchanges heat with the first evaporator 51 and the second evaporator 52 respectively. The first evaporator 51 is mainly responsible for the sensible heat load, and the second evaporator 52 is mainly responsible for the latent heat load. After exchanging heat with the second evaporator 52, a large amount of water is released from the air, reducing the air's moisture content. Subsequently, it exchanges heat with the first condenser 20. The cooled and dehumidified air is heated into high-temperature, low-humidity, dry hot air, which enters the clothing storage cavity 100 through the air outlet of the air duct 90 to dry the clothes, taking away the moisture from the clothes. After completing the heat and moisture exchange with the clothes, it becomes low-temperature, high-humidity air again, and then exchanges heat with the first evaporator 51 and the second evaporator 52 again, thus completing the entire air-side circulation.

[0074] The heat pump dryer of this invention employs a quasi-two-stage compression system. The compressor has two compression chambers: a first compression chamber 1a and a second compression chamber 1b, as described above. The first compression chamber 1a corresponds to the first evaporator 51, which is a high-temperature evaporator, and the first compression chamber 1a is a high-temperature compression chamber. The first compression chamber 1a has an intake port, an exhaust port, and an optional gas inlet. The second compression chamber 1b corresponds to the second evaporator 52, which is a low-temperature evaporator, and the corresponding second compression chamber 1b is a low-temperature compression chamber. The second compression chamber 1b has an intake port, a gas inlet, and an exhaust port. The exhaust gases from both the first compression chamber 1a and the second compression chamber 1b are ultimately mixed and discharged. The quasi-two-stage gas inlet can not only replenish the second compression chamber 1b but also the first compression chamber 1a, further reducing the exhaust temperature, decreasing the pressure ratio, and improving system energy efficiency.

[0075] The heat pump dryer of the present invention adopts a dual-temperature circulation system. The first evaporator 51, the second evaporator 52, and the first condenser 20 are arranged in the air duct 90 along the air flow direction. The air outlet of the clothes receiving cavity 100 flows through the first evaporator 51, the second evaporator 52, and the first condenser 20 in sequence, and after heat and moisture exchange, it enters the clothes receiving cavity 100 to dry the clothes to be dried.

[0076] This invention employs a quasi-two-stage compression coupled with cascade heat exchange system circulation, fully leveraging the advantages of both the quasi-two-stage and dual-temperature systems. The quasi-two-stage system, through gas injection, lowers the exhaust temperature and evaporator inlet specific enthalpy, increasing the system's heat exchange capacity and significantly enhancing volumetric cooling capacity, thus improving system energy efficiency. The dual-temperature system achieves cascade cooling and dehumidification; the low-temperature evaporation temperature increases the system's dehumidification capacity, resulting in low moisture content in the evaporator outlet air. While maintaining a nearly constant drum inlet air temperature, reducing the moisture content in the drum inlet air facilitates the extraction of moisture from clothing, thereby shortening drying time.

[0077] This invention also adds a second condenser 70 outside the air duct 90, which can sometimes be called a waste heat radiator. A dedicated cooling fan 62 dissipates heat from this condenser. Once the condensing temperature and exhaust temperature reach a certain threshold, the cooling fan 62 is turned on to assist the system in cooling down, thereby reducing the outlet temperature of the clothing container 100, lowering the evaporation temperature, and improving the system's dehumidification capacity. In addition, the second condenser 70 can also reduce the condensing temperature and exhaust temperature, ensuring that the system can still operate safely and stably under high-frequency conditions. The system does not need to reduce the frequency to ensure its reliability, thereby improving drying efficiency and shortening drying time.

[0078] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A heat pump clothes dryer, characterized in that: The heat pump dryer includes a clothing storage cavity (100) and an air duct (90). The air outlet of the air duct (90) is connected to the air inlet of the clothing storage cavity (100), and the air outlet of the clothing storage cavity (100) is connected to the air inlet of the air duct (90). The heat pump dryer also includes a refrigerant circulation loop formed by sequentially connecting a compression mechanism (10), a first condenser (20), a first throttling device (31), and an evaporator (5). The evaporator (5) and the first condenser (20) are both located in the air duct (90), and the evaporator (5) is located on the upwind side of the first condenser (20). The heat pump dryer also includes a second condenser (70) and a heat dissipation mechanism. The second condenser (70) is disposed on the refrigerant circulation loop and located outside both the clothes accommodating cavity (100) and the air duct (90). The heat dissipation mechanism is used to dissipate heat from the second condenser (70) and can be turned on or off.

2. The heat pump dryer according to claim 1, characterized in that: The heat dissipation mechanism includes a heat dissipation fan (62), which dissipates heat from the second condenser (70) through the heat dissipation fan (62).

3. The heat pump dryer according to claim 1 or 2, characterized in that: The evaporator (5) includes a first evaporator (51) and a second evaporator (52). The first evaporator (51) is located on the upwind side of the second evaporator (52). The compression mechanism (10) includes a first compression chamber (1a) and a second compression chamber (1b) that are independent of each other. The exhaust ports of both the first compression chamber (1a) and the second compression chamber (1b) are connected to the refrigerant inlet of the first condenser (20). One end of both the first evaporator (51) and the second evaporator (52) is connected to the end of the first throttling device (31) that is away from the first condenser (20). The other end of the first evaporator (51) is connected to the air intake (11) of the first compression chamber. The other end of the second evaporator (52) is connected to the air intake (12) of the second compression chamber.

4. The heat pump dryer according to claim 3, characterized in that: One end of both the first evaporator (51) and the second evaporator (52) is connected to the end of the first throttling device (31) away from the first condenser (20) via a gas-liquid separator (40); the gas-liquid separator (40) has an inlet (41), a liquid outlet (42), and a gas outlet (43). The gas-liquid separator (40) is connected to the end of the first throttling device (31) away from the first condenser (20) via the inlet (41), and is connected to one end of both the first evaporator (51) and the second evaporator (52) via the liquid outlet (42); wherein, The second compression chamber (1b) has an A air inlet (13), which is connected to the gas outlet (43) of the gas-liquid separator (40).

5. The heat pump dryer according to claim 4, characterized in that: The compression mechanism (10) includes a compressor, and the first compression chamber (1a) and the second compression chamber (1b) are two independent compression chambers of the same compressor; wherein, the compressor also has a first partition plate (1) separating the first compression chamber (1a) and the second compression chamber (1b), and a first gas supply channel (2) is provided on the first partition plate (1), and the gas outlet (43) of the gas-liquid separator (40) is connected to the A gas supply port (13) through the first gas supply channel (2).

6. The heat pump dryer according to claim 4, characterized in that: The first compression chamber (1a) has a B air inlet (14), which is connected to the gas outlet (43) of the gas-liquid separator (40).

7. The heat pump dryer according to claim 6, characterized in that: The compression mechanism (10) includes a compressor, and the first compression chamber (1a) and the second compression chamber (1b) are two independent compression chambers of the same compressor; wherein, the compressor also has a second partition plate (74) separating the first compression chamber (1a) and the second compression chamber (1b), and the second partition plate (74) is provided with a second gas supply channel (7), and the gas outlet (43) of the gas-liquid separator (40) is connected to both the A gas supply port (13) and the B gas supply port (14) through the second gas supply channel (7).

8. The heat pump dryer according to any one of claims 4-7, characterized in that: A second throttling device (32) is provided on the pipeline between the first evaporator (51) and the liquid outlet (42); and / or, a third throttling device (33) is provided on the pipeline between the second evaporator (52) and the liquid outlet (42).

9. The heat pump dryer according to any one of claims 1-2 and 4-7, characterized in that: The first condenser (20) and the second condenser (70) are connected in series.

10. A control method for a heat pump dryer according to any one of claims 1-9, characterized in that: Includes the following steps: Step S1: Determine whether the exhaust temperature of the compression mechanism (10) is greater than or equal to the first preset value, and whether the temperature of the first condenser (20) is greater than or equal to the second preset value; Step S2: If the exhaust temperature of the compression mechanism (10) is greater than or equal to the first preset value, and the temperature of the first condenser (20) is greater than or equal to the second preset value, then the heat dissipation mechanism is turned on; if the exhaust temperature of the compression mechanism (10) is less than the first preset value, and / or the temperature of the first condenser (20) is less than the second preset value, then the heat dissipation mechanism is turned off.

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