Clothes dryer

Abstract

The invention relates to a clothes dryer, comprising a clothes drying chamber for accommodating clothes; the two ends of the air channel are in fluid communication with the clothes drying chamber; the fan is located in the air channel and promotes air to circulate in the clothes drying chamber and the air channel; the heat pump loop comprises a first heat exchanger, a second heat exchanger and a compressor which are connected with one another and allow a first refrigerant to circularly flow in the heat pump loop, and the heat pump loop further comprises a third heat exchanger and a fourth heat exchanger, and the first heat exchanger and the fourth heat exchanger are located in the air channel and used for heating and dehumidifying passing air respectively. The fourth heat exchanger is independent relative to the heat pump loop, so that the type of the heat exchanger can be selected more flexibly, the fourth heat exchanger can be controlled independently, and the purpose of improving the clothes drying efficiency can be effectively achieved.

Description

[Technical Field]

[0001] This invention relates to a heat exchange system for a clothes dryer, the heat exchange system comprising a heat pump circuit. [Background Technology]

[0002] Known heat pump dryers consist of a condenser that heats the air and an evaporator that dehumidifies the air. Both the condenser and evaporator are located in the air circuit and perform heating and cooling functions respectively. In the early stages of the drying process, the air temperature needs to rise. At this time, the evaporator's cooling effect on the air significantly reduces the heating efficiency, prolonging the heating time. In the later stages of the drying process, the air's moisture saturation is low, and the evaporator's condensation efficiency is poor, resulting in a longer drying time and thus requiring more electrical energy. [Summary of the Invention]

[0003] The object of this invention includes improving the drying efficiency of heat pump dryers.

[0004] An embodiment of the present invention discloses a clothes dryer, comprising a drying chamber for holding clothes; an air passage with both ends in fluid communication with the drying chamber; a fan located within the air passage to circulate air within the drying chamber and the air passage; and a heat pump circuit comprising a first heat exchanger, a second heat exchanger, and a compressor interconnected therein and allowing a first refrigerant to circulate therein. The first heat exchanger is located within the air passage and is used to heat the passing air; the second heat exchanger is located outside the air passage and is configured to exchange heat with a third heat exchanger, thereby absorbing heat from the third heat exchanger; and a fourth heat exchanger, which transfers heat to the third heat exchanger, is located within the air passage and is used to absorb heat from the passing air, thereby condensing moisture in the air.

[0005] Optional embodiments further include: a third heat exchanger and the fourth heat exchanger located on the second refrigerant circuit, wherein the second refrigerant circulates.

[0006] Optional embodiments further include: the heat exchange efficiency of the fourth heat exchanger is higher than that of the second heat exchanger.

[0007] Optional embodiments also include: the second refrigerant being water.

[0008] Optional embodiments include: a second refrigerant circuit comprising an inlet valve, a circulation pump, and a drainage device.

[0009] Optional embodiments include: the upstream of the third heat exchanger is connected to the inlet valve, and the downstream is connected to the drainage device; and / or, the upstream of the fourth heat exchanger is connected to the circulating pump, and the downstream is connected to the third heat exchanger.

[0010] Optionally, an embodiment includes a control device configured to control the operation of a dryer according to a first control method, the first control method comprising the steps of: turning on the compressor and the fan; opening the water inlet valve for a period of time while simultaneously turning on the circulation pump to fill the second refrigerant circuit with water and circulate therein; and determining that drying is complete and ending the drying process.

[0011] Optional embodiments include: after determining that drying is complete, turning on the drainage device to drain the water in the second refrigerant circuit.

[0012] Optionally, an embodiment includes a control device configured to control the operation of a dryer according to a second control method, the second control method comprising the steps of: turning on the compressor and fan; turning on the water inlet valve and drain device; determining that the heating phase is over, turning off the water inlet valve and drain device, turning on the circulation pump to circulate water in the second refrigerant circuit; and determining that drying is complete and ending the drying process.

[0013] Optional embodiments include: the step of determining the end of the heating phase includes: obtaining the temperature of the air leaving the drying chamber, and determining the end of the heating phase when the temperature exceeds a preset temperature.

[0014] Optional embodiments include: during the step of opening the inlet valve and the drain device, the inlet valve and the drain device are continuously open, or the inlet valve and the drain device are opened and closed in stages.

[0015] Optional embodiments include: including an auxiliary heating device disposed in the air passage for auxiliary heating of the air passing through it.

[0016] Optional embodiments include: a control device configured to control the operation of the dryer according to a third control method, the third control method comprising the steps of: turning on the compressor and fan; turning on the auxiliary heating device; turning on the water inlet valve and the drain device; determining that the heating phase is over, controlling the water inlet valve, the drain device and the circulation pump to maintain the water temperature in the second refrigerant circuit within a set range; and determining that drying is complete and ending the drying process.

[0017] Optional embodiments include steps for controlling the inlet valve, drain device, and circulation pump, including alternating water circulation and water exchange in the second refrigerant circuit.

[0018] Optional embodiments include: the step of determining the end of the heating phase includes: obtaining the temperature of the air leaving the drying chamber, and determining the end of the heating phase when the temperature exceeds a preset temperature.

[0019] Optional embodiments include: a control device that presets multiple drying modes selectable by the user, each drying mode corresponding to a control method, wherein the control device selects the corresponding control method according to the drying mode selected by the user to control the operation of the dryer.

[0020] The heat exchange efficiency of the fourth heat exchanger is higher than that of the second heat exchanger.

[0021] Where technical conditions permit, the above embodiments can be combined in various arbitrary ways.

[0022] In various embodiments of the present invention, the second heat exchanger for cooling in the heat pump is located outside the air passage. Instead, a fourth heat exchanger absorbs heat from the air to dehumidify it. This fourth heat exchanger is independent of the heat pump circuit, allowing for more flexible selection of its type and independent control to be flexibly configured according to different needs during the drying process, ultimately effectively improving drying efficiency. For example, in some embodiments, a fourth heat exchanger with higher heat exchange efficiency is used to improve dehumidification efficiency during the drying process, especially in the later stages. And / or, in some embodiments, the fourth heat exchanger is allowed to be inactive during the heating phase, thereby accelerating the heating process.

[0023] The following description, in conjunction with the accompanying drawings, illustrates some specific embodiments of the present invention. Various other advantages of the present invention will also be selectively described below with reference to these specific embodiments. Some benefits of the present invention, even if not explicitly stated, are readily apparent to those skilled in the art through simple deduction, and therefore will not be exhaustively listed below. [Attached Image Description]

[0024] Figure 1 This is a schematic diagram of a clothes dryer according to one embodiment.

[0025] Figure 2 This is a flowchart of the first control method for a clothes dryer.

[0026] Figure 3 This is a flowchart of the second control method for a clothes dryer.

[0027] Figure 4 This is a flowchart of the third control method for a clothes dryer. [Specific Implementation Examples]

[0028] To make the technical problems to be solved, the technical solutions, and the beneficial technical effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and several exemplary embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Various embodiments may share the same view or multiple views for description, but not all features appearing in the same view should be interpreted as features that an embodiment must possess. Instead, they can be combined in any suitable manner as long as they are not technically mutually exclusive. Moreover, for the sake of brevity, different embodiments of different aspects may be presented in the same specific design; however, such presentation does not mean that embodiments of these aspects should appear together. The disassembly and / or combination of all possible embodiments and / or technical features should also take into account the description in the specification and what a person skilled in the art can directly and unambiguously determine based on the description in the specification.

[0029] like Figure 1 In the illustrated embodiment, the dryer 100 includes a drying chamber 1 for holding clothes. The dryer 100 can be a tumble dryer or a cabinet dryer. Therefore, the drying chamber 1 can be cylindrical or a cavity formed within a cabinet, without being limited by its specific form. An air passage 2 includes an air inlet 21 and an air outlet 22, both of which are in fluid communication with the drying chamber 1. Thus, the air passage 2 and the drying chamber 1 together form an air circuit. A fan 3 is located within the air passage 2, causing air to enter the drying chamber 1 from the air outlet 22 of the air passage 2, and then return to the air passage 2 from the air inlet 21 of the air passage 2, thereby circulating within the circuit formed by the drying chamber 1 and the air passage 2.

[0030] The heat pump circuit 4 includes a first heat exchanger 41, a second heat exchanger 42, a throttling device 43, and a compressor 44, all interconnected and allowing a first refrigerant to circulate within it. The first heat exchanger 41, often referred to as a condenser, is located within the air passage 2 and is used to heat the passing air. The first heat exchanger 41 is positioned further downstream of the air passage 2 in the airflow direction. The air heated by the first heat exchanger 41 enters the drying chamber 1 from the outlet 22, heating the clothes and causing moisture to evaporate. The air then becomes humid. The hot, humid air re-enters the air passage 2 from the inlet 21. The hot, humid air is then cooled and dehumidified within the air passage 2. This will be described further below.

[0031] The second heat exchanger 42, commonly referred to as an evaporator, is located outside the air passage 2. The second heat exchanger 42 needs to absorb heat from the outside to achieve thermal equilibrium in the heat pump circuit 4. The second heat exchanger 42 is configured to exchange heat with the third heat exchanger 53, thereby absorbing heat from the third heat exchanger 53. The connection and / or positional relationship between the second heat exchanger 42 and the third heat exchanger 53 can be any known and applicable method, such as mutual contact, enclosed surround, or interlocking.

[0032] A fourth heat exchanger 54, which transfers heat to the third heat exchanger 53, is located within the air passage 2 and is used to absorb heat from the passing air. The fourth heat exchanger 54 is located upstream of the first heat exchanger 41 in the direction of air flow. After the high-temperature and high-humidity air described above enters the air passage 2 from the drying chamber 1, it first passes through the fourth heat exchanger 54, whereupon heat is absorbed and the air is cooled. At least some of the moisture in the air condenses, thus dehumidifying the air.

[0033] Therefore, without considering heat loss, the first heat exchanger 41, the second heat exchanger 42, the third heat exchanger 53, and the fourth heat exchanger 54 together form a heat transfer loop. Heat is drawn in from the fourth heat exchanger 54 and sequentially transferred to the third heat exchanger 53, the second heat exchanger 42, and the first heat exchanger 41, and finally transferred from the first heat exchanger 41 to the air, heating the air.

[0034] The third heat exchanger 53 and the fourth heat exchanger 54 can be various other heat transfer devices besides heat pump heat exchangers. In particular, a preferred embodiment includes a fourth heat exchanger 54 with a higher heat transfer efficiency than the second heat exchanger 42.

[0035] For example, the third heat exchanger 53 and the fourth heat exchanger 54 can be solid heat-conducting components, such as those made of metallic materials. They are thermally connected, in contact, or are two parts of a single unit.

[0036] For example, such as Figure 1 In the embodiment shown, the third heat exchanger 53 and the fourth heat exchanger 54 are located on the second refrigerant circuit 5, in which the second refrigerant circulates.

[0037] exist Figure 1In the illustrated embodiment, the second refrigerant is water. The second refrigerant circuit 5 includes a water inlet valve 51, connected to a water source that can be tap water or a water storage device within the dryer 100. The second refrigerant circuit 5 also includes a circulation pump 52 and a drain device 55. The circulation pump 52 circulates water between the third heat exchanger 53 and the fourth heat exchanger 54. The drain device 55 can be a drain pump, or in some cases, a drain valve, which, when opened, discharges the water in the second refrigerant circuit 5 under gravity. To improve heat exchange efficiency with air, the fourth heat exchanger 54 can be a tubular heat exchanger, comprising tubes made of thermally conductive material bent into a specific shape through which water flows. The third heat exchanger 53 can be of the same type, or a water tank in which the second heat exchanger 42 is housed.

[0038] More advantageously, the upstream of the third heat exchanger 53 is connected to the inlet valve 51, and the downstream is connected to the drain device 55. Therefore, when both the inlet valve 51 and the drain device 55 are open, water flows directly out after passing through the third heat exchanger 53, bypassing the fourth heat exchanger 54. The upstream of the fourth heat exchanger 54 is connected to the circulation pump 52, rather than directly to the inlet valve 51, and the downstream is connected to the third heat exchanger 53. Thus, water can only pass through the fourth heat exchanger 54 when the circulation pump 52 is running. This allows for control of the water flow path, thereby controlling whether and how the third and fourth heat exchangers 53 and 54 operate. This will be further explained below in conjunction with the drying process.

[0039] Optionally, the dryer 100 includes an auxiliary heating device 6 disposed within the air passage 2 for auxiliary heating of the passing air. The auxiliary heating device 6 is located downstream of the fourth heat exchanger 54 and heats the air cooled by the fourth heat exchanger 54. The auxiliary heating device 6 may be, for example, a PTC heating device.

[0040] The dryer 100 also includes a control device 8. The control device 8 has preset multiple drying modes for the user to choose from. Each drying mode corresponds to a control method. When the user selects a drying mode and starts the drying program, the control device 8 controls the operation of the dryer 100 according to the corresponding control method.

[0041] In an optional embodiment, the control device 8 presets an energy-saving drying mode and a normal drying mode.

[0042] When the energy-saving drying mode is activated, the control device 8 controls the operation of the dryer 100 according to the first control method.

[0043] like Figure 2 As shown, the first control method includes the following steps:

[0044] S11: Start compressor 44 and fan 3. At this time, air circulation is formed, and the first heat exchanger 41 and the second heat exchanger 42 start working. The first heat exchanger 41 starts heating the air.

[0045] S12: Open the inlet valve 51 and the circulation pump 52 to fill the second refrigerant circuit 5 with water and circulate it within it. The second heat exchanger 42 needs to absorb heat after it starts working. This step allows the second heat exchanger 42 to absorb heat from the circulating water. At the same time, in the subsequent drying process, the circulating water absorbs heat from the air through the fourth heat exchanger 54 to dehumidify the air.

[0046] S13: The inlet valve closes after being open for a period of time. This can generally be controlled by time to ensure that the second refrigerant circuit 5 is filled with enough circulating water.

[0047] S14: Determine if drying is complete and end the drying process. The method for determining if drying is complete can be a known and suitable method.

[0048] Upon completion of drying, the drain device 55 is activated to drain the water from the second refrigerant circuit 5. The first control method also includes other control details, which are omitted here as they are less relevant to the key points of this embodiment. The same applies to the following descriptions of other control methods.

[0049] In the first control method, the water-cooled fourth heat exchanger 54 is responsible for dehumidifying the air. Especially in the later stages of the drying process when the air moisture content is low, the fourth heat exchanger 54 exhibits better heat exchange efficiency. Compared to conventional heat pump dryers in the prior art, this method achieves higher drying efficiency in the later stages, thus ending the drying process earlier and saving energy. Furthermore, due to the use of circulating water, water consumption is also reduced.

[0050] When the normal drying mode is running, the control device 8 controls the operation of the dryer 100 according to the second control method.

[0051] like Figure 3 As shown, the second control method includes the following steps:

[0052] S21: Start compressor 44 and fan 3. At this time, air circulation is formed, and the first heat exchanger 41 and the second heat exchanger 42 start working. The first heat exchanger 41 starts heating the air.

[0053] S22: Open the water inlet valve 51 and the drain device 55. In this step, water enters through the water inlet valve 51, flows through the third heat exchanger 53, is heated by the second heat exchanger 42, and is discharged through the drain device 55. Preferably, the circulation pump 52 is not turned on at this time, and the water does not pass through the fourth heat exchanger 54, thus preventing the circulating air in the air channel 2 from being cooled, allowing the air to heat up quickly and improving drying efficiency. In this step, the water inlet valve 51 and the drain device 55 can be continuously opened, or they can be opened and closed in stages to reduce water usage.

[0054] S23: Determine whether the heating phase has ended. This includes: acquiring the temperature of the air leaving the drying chamber 1; when the temperature exceeds a preset temperature, i.e., T≥Ta, the heating phase is considered complete. The air temperature leaving the drying chamber 1 can be measured by a sensor 7 installed near the air inlet 21 of the air channel 2. The preset temperature may vary depending on the program settings, for example, it may be a value between 30 and 50 degrees Celsius.

[0055] S24: After determining whether the heating phase has ended, close the inlet valve 51 and the drain device 55, and start the circulating pump 52 to circulate water in the second refrigerant circuit 5. This step allows the second heat exchanger 42 to absorb heat from the circulating water. At the same time, the circulating water absorbs heat from the air through the fourth heat exchanger 54, dehumidifying the air.

[0056] S25: Determine that drying is complete and end the drying process.

[0057] In the second control method, not only can the early stage of the drying process, i.e., the heating stage, be completed more quickly, saving time and energy, but also the fourth heat exchanger 54 has better heat exchange efficiency in the later stage of the drying process when the air moisture content is lower. Compared with ordinary heat pump dryers in the prior art, the dryer has higher drying efficiency in the later stage, thus ending the drying process earlier and saving energy.

[0058] In some embodiments, the dryer 100 may also include only the first control method or the second control method. Compared with existing dryers, it already has the advantages of higher drying efficiency and greater energy saving.

[0059] In an embodiment where the dryer 100 is equipped with an auxiliary heating device 6, the control device 8 presets a quick drying mode. This quick drying mode can be the default mode, or it can be selected by the user from the energy-saving drying mode and / or the normal drying mode described above.

[0060] When the quick drying mode is activated, the control device 8 controls the operation of the dryer 100 according to the third control method.

[0061] like Figure 4 As shown, the third control method includes the following steps:

[0062] S31: Start compressor 44 and fan 3. At this time, air circulation is formed, and the first heat exchanger 41 and the second heat exchanger 42 start working. The first heat exchanger 41 starts heating the air.

[0063] S32: Turn on the auxiliary heating device 6 to heat the circulating air. The auxiliary heating device 6 and the compressor 44 can be turned on simultaneously or sequentially.

[0064] S33: Open the water inlet valve 51 and the drain device 55. In this step, water enters through the water inlet valve 51, flows through the third heat exchanger 53, is heated by the second heat exchanger 42, and is discharged through the drain device 55. Preferably, the circulation pump 52 is not turned on at this time, and the water does not pass through the fourth heat exchanger 54, thus preventing the circulating air in the air channel 2 from being cooled, allowing the air to heat up quickly and improving drying efficiency. In this step, the water inlet valve 51 and the drain device 55 can be continuously opened, or they can be opened and closed in stages to reduce water usage.

[0065] Steps S32 and S33 do not have to be parallel; they can have a sequential relationship, depending on the actual situation.

[0066] S34: Determine whether the heating phase has ended. This includes: acquiring the temperature of the air leaving the drying chamber 1; when the temperature exceeds a preset temperature, i.e., T≥Tb, the heating phase is considered complete. The air temperature leaving the drying chamber 1 can be measured by a sensor 7 installed near the air inlet 21 of the air channel 2. The preset temperature may vary depending on the program settings. Ta may be the same as or different from Tb.

[0067] S35: After determining whether the heating stage has ended, control the inlet valve 51, drain device 55, and circulation pump 52 to maintain the water temperature in the second refrigerant circuit 5 within the set range. Water temperature control can be achieved by detecting the signal from a temperature sensor installed in the second refrigerant circuit 5. In this step, the control of the inlet valve 51, drain device 55, and circulation pump 52 involves alternating water circulation and water exchange in the second refrigerant circuit 5. When the water temperature is lower than the preset temperature, water is recycled; when the water temperature exceeds the preset temperature, water is drained and new water is introduced. This allows for more economical use of water resources and provides higher drying efficiency in the later stages of the drying process compared to a normal drying mode.

[0068] S36: Determine if drying is complete and end the drying process.

[0069] In the third control method, not only can the early stage of the drying process, i.e., the heating stage, be completed more quickly, saving time and energy, but also the fourth heat exchanger 54 has better heat exchange efficiency in the later stage of the drying process when the air moisture content is lower. Compared with ordinary heat pump dryers in existing technology, it has higher drying efficiency in the later stage of the drying process, and it also has higher drying efficiency compared with ordinary drying modes, only requiring more water.

[0070] The various specific embodiments described above and shown in the accompanying drawings are for illustrative purposes only. Any modifications made by those skilled in the art within the scope of the basic technical concept of this invention are within the protection scope of this invention.

Claims

1. Clothes dryer, including: Drying room (1), used to store clothes; Air passage (2), both ends of which are in fluid communication with the drying chamber (1); A fan (3), located within the air passage (2), circulates air within the drying chamber (1) and the air passage (2); and The heat pump circuit (4) includes a first heat exchanger (41), a second heat exchanger (42), and a compressor (44) that are interconnected and allow a first refrigerant to circulate therein. Its features are: The first heat exchanger (41) is located inside the air passage (2) and is used to heat the air passing through it; the second heat exchanger (42) is located outside the air passage (2) and is configured to exchange heat with the third heat exchanger (53) to absorb heat from the third heat exchanger. A fourth heat exchanger (54), which transfers heat to the third heat exchanger (53), is located in the air passage (2) and is used to absorb heat from the passing air, thereby causing moisture in the air to condense.

2. The clothes dryer as described in claim 1, characterized in that: The third heat exchanger (53) and the fourth heat exchanger (54) are located on the second refrigerant circuit (5), in which the second refrigerant circulates.

3. The clothes dryer as described in claim 1 or 2, characterized in that: The heat exchange efficiency of the fourth heat exchanger (54) is higher than that of the second heat exchanger (42).

4. The clothes dryer as described in claim 2, characterized in that: The second refrigerant is water.

5. The clothes dryer as described in claim 4, characterized in that: The second refrigerant circuit (5) includes an inlet valve (51), a circulation pump (52), and a drain device (55).

6. The clothes dryer as described in claim 5, characterized in that: The upstream of the third heat exchanger (53) is connected to the inlet valve (51), and the downstream is connected to the drain device (55); and / or The upstream of the fourth heat exchanger (54) is connected to the circulating pump (52), and the downstream is connected to the third heat exchanger (53).

7. The clothes dryer as described in claim 6, characterized in that: Includes a control device (8), configured to control the operation of a dryer according to a first control method, the first control method comprising the steps of: Turn on the compressor and fan; Open the inlet valve for a period of time, and at the same time start the circulation pump to fill the second refrigerant circuit with water and circulate it in it; Once the drying process is complete, the drying process can be terminated.

8. The clothes dryer as described in claim 7, characterized in that: Once the drying process is complete, turn on the drain device to discharge the water from the second refrigerant circuit.

9. The clothes dryer as described in claim 6, characterized in that: Includes a control device (8), configured to control the operation of the dryer according to a second control method, the second control method comprising the steps of: Turn on the compressor and fan; Open the inlet valve and drain device; When the heating phase is over, close the inlet valve and drain device, and turn on the circulation pump to circulate water in the second refrigerant circuit. Once the drying process is complete, the drying process will end.

10. The clothes dryer as described in claim 9, characterized in that: The steps to determine the end of the heating phase include: obtaining the temperature of the air leaving the drying chamber, and determining the end of the heating phase when the temperature exceeds the preset temperature.

11. The clothes dryer as described in claim 9, characterized in that: During the steps of opening the inlet valve and the drain device, the inlet valve and the drain device are continuously open, or the inlet valve and the drain device are opened and closed in stages.

12. The clothes dryer as described in claim 6, characterized in that: It includes an auxiliary heating device (6) disposed in the air channel (2) for auxiliary heating of the air passing through it.

13. The clothes dryer as described in claim 12, characterized in that: Includes a control device (8), configured to control the operation of the dryer according to a third control method, the third control method comprising the steps of: Turn on the compressor and fan; Turn on the auxiliary heating device; Open the inlet valve and drain device; When the heating phase is about to end, control the inlet valve, drain device and circulation pump to keep the water temperature in the second refrigerant circuit within the set range; Once the drying process is complete, the drying process will end.

14. The clothes dryer as described in claim 13, characterized in that: The steps for controlling the inlet valve, drain device, and circulation pump include alternating between circulating water in the second refrigerant circuit and water exchange.

15. The clothes dryer as described in claim 14, characterized in that: The steps to determine the end of the heating phase include: obtaining the temperature of the air leaving the drying chamber, and determining the end of the heating phase when the temperature exceeds the preset temperature.

16. The clothes dryer as described in claim 6, characterized in that: Includes a control device (8), which presets multiple drying modes that can be selected by the user. Each drying mode corresponds to a control method. The control device selects the corresponding control method according to the drying mode selected by the user to control the operation of the dryer (100).

17. The clothes dryer as described in claim 1, characterized in that: The heat exchange efficiency of the fourth heat exchanger (54) is higher than that of the second heat exchanger (42).

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