Rotary wheel dehumidification system and control method thereof

Abstract

The invention relates to the technical field of air treatment equipment, in particular to a rotating wheel dehumidification system and a control method thereof. The rotating wheel dehumidification system comprises at least one rotating wheel, a low-temperature dehumidification side and a high-temperature regeneration side, the low-temperature dehumidification side is provided with a dehumidification area and an evaporator, and a first working medium circulates in the evaporator; the high-temperature regeneration side is provided with at least one gradient condensation heat pump system, and the gradient condensation heat pump systems are in one-to-one correspondence with the rotating wheels and are used for carrying out gradient heating on airflow before entering the regeneration area of each rotating wheel. The gradient condensation heat pump system comprises a plurality of heat pump systems for sequentially heating airflow. The regeneration temperature and the system energy consumption can be considered at the same time, the overall energy-saving performance and the regeneration temperature of the rotary dehumidification system are improved, and the purpose of saving energy to the maximum degree on the premise that the high regeneration temperature is achieved is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of air treatment equipment, and in particular to a rotary dehumidification system and a control method thereof. Background Art

[0002] The rotary dehumidifier unit includes a rotary wheel, a low-temperature dehumidification side, and a high-temperature regeneration side. The rotary wheel includes a regeneration area and a dehumidification area. At present, the rotary dehumidifier unit usually adopts electric heating or steam heating or a single-stage heat pump (single or multiple sets) to regenerate and heat the regeneration area of ​​the rotary wheel. Among them, the energy consumption of regenerative steam heating or electric heating is high; a single-stage heat pump system cannot provide a higher regeneration temperature, and the overall system energy saving is low; the use of multiple single-stage heat pump systems, although the regeneration temperature can be increased, leads to high system cost and high energy efficiency. Therefore, the existing rotary dehumidifier unit has the problem of not being able to take into account both the regeneration temperature and the system energy consumption at the same time. Summary of the invention

[0003] In view of the above problems, the present invention is proposed to provide a combined air-conditioning unit and a control method thereof that overcome the above problems or at least partially solve the above problems, aiming to solve the problem that the existing rotary dehumidification system cannot take into account both the regeneration temperature and the system energy consumption, so as to improve the overall energy saving and regeneration temperature of the rotary dehumidification system.

[0004] In one aspect, the present invention provides a rotary dehumidification system, comprising:

[0005] at least one rotor, the rotor comprising a regeneration region and a dehumidification region;

[0006] A low-temperature dehumidification side, wherein the low-temperature dehumidification side is provided with the dehumidification area and an evaporator, and a first working medium flows in the evaporator;

[0007] On the high-temperature regeneration side, at least one gradient condensation heat pump system is provided on the high-temperature regeneration side, and the gradient condensation heat pump system corresponds to the rotor one-to-one, and is used to perform gradient heating on the airflow before entering the regeneration area of ​​each rotor; the gradient condensation heat pump system includes a plurality of heat pump systems for heating the airflow in sequence, wherein the working fluid of the heat pump system for heating the airflow for the last time is the upper working fluid, and the working fluid of the heat pump system for heating the airflow for the next time is the lower working fluid, and the lower working fluid absorbs heat during evaporation and exchanges heat with the upper working fluid that releases heat during condensation through the first intermediate heat exchanger; the heat pump system for heating the airflow for the first time uses the first working fluid flowing out of the evaporator to heat the airflow for the first time.

[0008] Optionally, the first intermediate heat exchanger comprises a first channel and a second channel, the first channel has an upper-level working medium flowing therein, and the second channel has a lower-level working medium;

[0009] Each of the heat pump systems comprises a condenser and a compressor, wherein the condenser is used to heat the air flow;

[0010] The condenser and compressor of the heat pump system for heating the airflow for the last time are recorded as the upper condenser and the upper compressor; the upper compressor is used to compress the upper working medium, and the outlet of the upper compressor is connected to the upper condenser;

[0011] The condenser and the compressor of the heat pump system for performing the next temperature increase on the airflow are recorded as the lower-stage condenser and the lower-stage compressor; the lower-stage compressor is used to compress the lower-stage working medium, the inlet of the lower-stage compressor is connected to the second channel corresponding to the first intermediate heat exchanger, and the outlet of the lower-stage compressor is connected to the lower-stage condenser;

[0012] The condenser and compressor of the heat pump system for heating the airflow for the first time are referred to as the first condenser and the first compressor; the first compressor is used to compress the first working fluid; the inlet of the first compressor is connected to the evaporator, and the outlet of the first compressor is connected to the first condenser.

[0013] Optionally, the rotary dehumidification system further includes a second intermediate heat exchanger;

[0014] The second intermediate heat exchanger comprises:

[0015] a liquid return pipe, wherein the outlet of the first channel through which the first working medium flows is connected to the inlet of the liquid return pipe, and the outlet of the first condenser is connected to the inlet of the liquid return pipe, and the outlet of the liquid return pipe is connected to the inlet of the evaporator through a first throttling pipeline;

[0016] a liquid inlet pipe, wherein the inlet of the liquid inlet pipe is connected to the outlet of the liquid return pipe through a second throttling pipeline, and the outlet of the liquid inlet pipe is connected to the inlet of the first compressor; the first working medium absorbing heat during evaporation in the liquid inlet pipe performs heat exchange with the first working medium releasing heat during condensation in the liquid return pipe;

[0017] The second intermediate heat exchanger is used to collect the first working medium cooled by the corresponding first intermediate heat exchanger and the first working medium cooled by the first condenser into the second intermediate heat exchanger for subcooling, and then enter the evaporator after throttling;

[0018] The heat pump system for heating the airflow for the first time further comprises a control valve, which is used to control the total flow rate of the working fluid in the heat pump system.

[0019] Optionally, the rotary dehumidification system comprises at least two rotary wheels, at least two rotary wheels are arranged in sequence along the flow direction of the airflow, and at least two gradient condensation heat pump systems are provided on the high-temperature regeneration side;

[0020] Each gradient condensing heat pump system is connected to the evaporator;

[0021] The evaporator is located between the dehumidification areas of the two wheels.

[0022] Optionally, a steam heating device is provided between the rotor and the gradient condensation heat pump system for reheating the airflow heated by the gradient condensation heat pump system.

[0023] The present invention also provides a control method for the rotary dehumidification system as described in any one of the above, comprising:

[0024] Obtaining the actual moisture content of the air at the outlet side of the dehumidification area of ​​the rotor;

[0025] The frequency of the compressor of each of the heat pump systems is controlled at least according to the actual moisture content.

[0026] Optionally, controlling the frequency of the compressor of each of the heat pump systems at least according to the actual moisture content comprises:

[0027] When the actual humidity is continuously higher than the first preset humidity within a first preset time, the temperature of the air heated by each of the heat pump systems is obtained and recorded as a first actual temperature;

[0028] If each of the first actual temperatures is lower than the respective first preset temperature, then at least the frequency of the compressor of each of the heat pump systems is increased.

[0029] Optionally, a steam heating device is provided between the rotor and the gradient condensation heat pump system;

[0030] If each of the first actual temperatures is lower than the respective first preset temperatures, at least the frequency of the compressor of each of the heat pump systems is increased, and then, the method further includes:

[0031] When the frequencies of the compressors are all increased to the maximum frequency, the air flow temperature at the air inlet side of the regeneration area of ​​the runner is obtained and recorded as the inlet temperature;

[0032] If the inlet temperature is continuously lower than the target temperature within the second preset time, the steam heating device is turned on until the inlet temperature is greater than or equal to the target temperature, and then the steam heating device is turned off.

[0033] Optionally, controlling the frequency of the compressor of each of the heat pump systems at least according to the actual moisture content comprises:

[0034] When the actual moisture content is continuously less than the second preset moisture content within a third preset time, at least reducing the frequency of the compressor of each of the heat pump systems;

[0035] When the actual moisture content is less than or equal to the second preset moisture content and less than or equal to the first preset moisture content, stopping reducing the frequency of the compressor;

[0036] Wherein, the first preset moisture content is greater than the second preset moisture content.

[0037] Optionally, a steam heating device is provided between the rotor and the gradient condensation heat pump system;

[0038] Controlling the frequency of each compressor of the heat pump system at least according to the actual moisture content comprises:

[0039] When the actual moisture content is continuously less than the second preset moisture content within a third preset time, reducing the heating power of the steam heating device or shutting down the steam heating device, and reducing the frequency of the compressor;

[0040] When the actual moisture content is less than or equal to the second preset moisture content and less than or equal to the first preset moisture content, stop reducing the frequency of the compressor, and maintain or increase the heating power of the steam heating device or turn on the steam heating device;

[0041] Wherein, the first preset moisture content is greater than the second preset moisture content.

[0042] In the rotary dehumidification system of the present invention, since a gradient condensation heat pump system is provided on the air inlet side of the regeneration area of ​​each rotary wheel, and each gradient condensation heat pump system includes multiple heat pump systems, and a first intermediate heat exchanger is provided between adjacent heat pump systems, under the action of the first intermediate heat exchanger, the lower working fluid can absorb heat from the upper working fluid, so that the heating temperature of the heat pump system that heats up the airflow next time is higher than the heating temperature of the heat pump system that heats up the airflow last time. When in use, multiple heat pump systems heat up the airflow multiple times, realizing gradient condensation heating and increasing the regeneration temperature of the regenerated air. Compared with electric heating or steam heating only in the prior art, the present invention reduces energy consumption and has a higher regeneration temperature; compared with a single set of single-stage heat pump systems in the prior art, the present invention increases the regeneration temperature and has lower energy consumption; compared with multiple sets of single-stage heat pump systems in the prior art, energy consumption is reduced and the purpose of maximizing energy saving is achieved. In summary, the present invention can take into account both the regeneration temperature and the system energy consumption, thereby improving the overall energy saving and regeneration temperature of the rotary dehumidification system, that is, achieving the purpose of maximizing energy saving while realizing a high regeneration temperature.

[0043] In addition, compared with the prior art, under the same conditions, the present invention also has the advantage of low operating cost. The present invention can also realize automatic control, remote monitoring, unattended operation, and has the advantage of simple maintenance.

[0044] Therefore, according to the following detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will be more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0046] Figure 1 is a schematic principle diagram of a rotary dehumidification system according to an embodiment of the present invention;

[0047] Figure 2 is a schematic flow chart of a control method of a rotary dehumidification system according to an embodiment of the present invention;

[0048] Figure 3 is a schematic flow chart of a control method of a rotary dehumidification system according to an embodiment of the present invention;

[0049] Figure 4 is a schematic flow chart of a control method of a rotary dehumidification system according to an embodiment of the present invention;

[0050] Figure 5 is a schematic flow chart of a control method of a rotary dehumidification system according to an embodiment of the present invention;

[0051] Figure 6 is a schematic flow chart of a control method of a rotary dehumidification system according to an embodiment of the present invention;

[0052] Figure 7 is a schematic flow chart of a control method for a rotary dehumidification system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] Refer to the following Figures 1 to 7 The rotary dehumidification system and control method thereof of the embodiment of the present invention are described. The directions or positional relationships indicated by "front", "rear", "upper", "lower", "top", "bottom", "inner", "outer", "lateral", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention.

[0054] The terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first", "second", etc. may explicitly or implicitly include at least one of the features, that is, include one or more of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. When a feature "includes or contains" one or some of the features it covers, unless otherwise specifically described, this indicates that other features are not excluded and may further include other features.

[0055] Unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed", "coupled" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. A person skilled in the art should be able to understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0056] Figure 1 It is a schematic principle diagram of a rotary dehumidification system according to an embodiment of the present invention. The present invention provides a rotary dehumidification system.

[0057] A rotary dehumidification system includes at least one rotary wheel 100, a low-temperature dehumidification side and a high-temperature regeneration side.

[0058] The wheel 100 includes a regeneration area and a dehumidification area.

[0059] A dehumidification area and an evaporator 200 are provided on the low-temperature dehumidification side, and a first working medium flows in the evaporator 200 .

[0060] The high-temperature regeneration side is provided with a regeneration area and at least one gradient condensation heat pump system. The gradient condensation heat pump system corresponds to the rotor 100 one by one and is used to perform gradient heating on the airflow before entering the regeneration area of ​​each rotor 100.

[0061] The gradient condensation heat pump system includes multiple heat pump systems that heat the airflow in sequence, wherein the working fluid of the heat pump system that heats the airflow for the last time is the upper working fluid, and the working fluid of the heat pump system that heats the airflow for the next time is the lower working fluid. When the lower working fluid absorbs heat during evaporation, it exchanges heat with the upper working fluid that releases heat during condensation through the first intermediate heat exchanger 400; the heat pump system that heats the airflow for the first time uses the first working fluid flowing out of the evaporator 200 to heat the airflow for the first time.

[0062] In this embodiment, the gradient condensation heat pump system may include 2 heat pump systems, or may include 3, 4, or 5 heat pump systems. The number of heat pump systems in each gradient condensation heat pump system may be set as required. A first intermediate heat exchanger 400 is provided between two adjacent heat pump systems.

[0063] Specifically, the heat pump system that heats the airflow for the last time is recorded as the upper heat pump system. The heat pump system that heats the airflow for the next time is recorded as the lower heat pump system. The heat pump system that heats the airflow for the first time is recorded as the first heat pump system 310. The upper heat pump system and the lower heat pump system are relative, and the upper working fluid and the lower working fluid are also relative.

[0064] For example, when the gradient condensation heat pump system includes two heat pump systems, the two heat pump systems are the first heat pump system 310 and the second heat pump system 320, respectively. The first heat pump system 310 is the upper heat pump system of the second heat pump system 320, and the second heat pump system 320 is the lower heat pump system of the first heat pump system 310. The first working fluid circulates in the first heat pump system 310, and the second working fluid circulates in the second heat pump system 320. The first working fluid is the upper working fluid of the second working fluid, and the second working fluid is the lower working fluid of the first working fluid. The first intermediate heat exchanger 400 between the first heat pump system 310 and the second heat pump system 320 performs heat exchange between the first working fluid and the second working fluid, and the second working fluid absorbs heat from the first working fluid. The working process of the rotary dehumidification system is as follows: the first working fluid flows out from the outlet (high temperature side) of the evaporator 200, and then enters the first heat pump system 310. The first heat pump system 310 uses the first working fluid to heat the airflow for the first time. The second heat pump system 320 uses the second working medium to heat the airflow for the second time. The airflow passes through the regeneration area of ​​the rotor 100 to form a regeneration airflow, that is, regeneration wind.

[0065] For example, when the gradient condensation heat pump system includes three heat pump systems, the three heat pump systems are respectively the first heat pump system 310, the second heat pump system 320 and the third heat pump system. The first heat pump system 310 is the upper heat pump system of the second heat pump system 320, the second heat pump system 320 is the lower heat pump system of the first heat pump system 310, the second heat pump system 320 is the upper heat pump system of the third heat pump system, and the third heat pump system is the lower heat pump system of the second heat pump system 320. The first working fluid flows in the first heat pump system 310, the second working fluid flows in the second heat pump system 320, and the third working fluid flows in the third heat pump system. The first working fluid is the upper working fluid of the second working fluid, the second working fluid is the lower working fluid of the first working fluid, the second working fluid is the upper working fluid of the third working fluid, and the third working fluid is the upper working fluid of the first working fluid. The first intermediate heat exchanger 400 between the first heat pump system 310 and the second heat pump system 320 performs heat exchange between the first working fluid and the second working fluid, and the second working fluid absorbs heat from the first working fluid. The first intermediate heat exchanger 400 between the second heat pump system 320 and the third heat pump system performs heat exchange between the second working fluid and the third working fluid, and the third working fluid absorbs heat from the second working fluid. The working process of the rotary dehumidification system is as follows: the first working fluid flows out from the outlet (high temperature side) of the evaporator 200 and then enters the first heat pump system 310. The first heat pump system 310 uses the first working fluid to heat the airflow for the first time. The second heat pump system 320 uses the second working fluid to heat the airflow for the second time. The third heat pump system uses the third working fluid to heat the airflow for the third time.

[0066] In this embodiment, since a gradient condensation heat pump system is provided on the air inlet side of the regeneration area of ​​each rotor 100, and each gradient condensation heat pump system includes multiple heat pump systems, and a first intermediate heat exchanger 400 is provided between adjacent heat pump systems, under the action of the first intermediate heat exchanger 400, the lower working fluid can absorb heat from the upper working fluid, so that the heating temperature of the heat pump system that heats up the airflow next time is higher than the heating temperature of the heat pump system that heats up the airflow last time. When in use, multiple heat pump systems heat up the airflow multiple times, realize gradient condensation heating, and increase the regeneration temperature of the regeneration wind. Compared with only electric heating or only steam heating in the prior art, the present invention reduces energy consumption and has a higher regeneration temperature; compared with a single set of single-stage heat pump systems in the prior art, the present invention increases the regeneration temperature and has lower energy consumption; compared with multiple sets of single-stage heat pump systems in the prior art, energy consumption is reduced and the purpose of maximizing energy saving is achieved. In summary, the present invention can take into account both the regeneration temperature and the system energy consumption, thereby improving the overall energy saving and regeneration temperature of the rotary dehumidification system, that is, achieving the purpose of maximizing energy saving while realizing a high regeneration temperature.

[0067] In addition, compared with the prior art, under the same conditions, the present invention also has the advantage of low operating cost. The present invention can also realize automatic control, remote monitoring, unattended operation, and has the advantage of simple maintenance.

[0068] In some embodiments of the present invention, the first intermediate heat exchanger 400 includes a first channel and a second channel, the first channel has an upper-level working medium flowing therein, and the second channel has a lower-level working medium therein.

[0069] Each heat pump system includes a condenser and a compressor. The condenser is used to heat the airflow. Each condenser is arranged along the flow direction of the airflow.

[0070] Among them, the condenser and compressor of the heat pump system that perform the last temperature increase on the airflow are recorded as the upper-stage condenser and the upper-stage compressor; the upper-stage compressor is used to compress the upper-stage working fluid, and the outlet of the upper-stage compressor is connected to the upper-stage condenser.

[0071] The condenser and compressor of the heat pump system for heating the airflow for the next time are referred to as the lower-stage condenser and the lower-stage compressor; the lower-stage compressor is used to compress the lower-stage working fluid, the inlet of the lower-stage compressor is connected to the second channel corresponding to the first intermediate heat exchanger 400, and the outlet of the lower-stage compressor is connected to the lower-stage condenser.

[0072] The heat pump system for heating the airflow for the first time is recorded as the first heat pump system 310, and the condenser and compressor of the first heat pump system 310 are recorded as the first condenser 311 and the first compressor 312; the first compressor 312 is used to compress the first working fluid; the inlet of the first compressor 312 is connected to the evaporator 200, and the outlet of the first compressor 312 is connected to the first condenser 311.

[0073] Specifically, when the gradient condensation heat pump system includes two heat pump systems, the two heat pump systems are respectively the first heat pump system 310 and the second heat pump system 320. The condenser and the compressor of the second heat pump system 320 are recorded as the second condenser 321 and the second compressor 322. The second working fluid circulates in the second heat pump system 320. The inlet of the first channel of the first heat exchanger is connected to the outlet of the first compressor 312. When in use, the gaseous first working fluid flows out from the outlet of the evaporator 200, and then flows into the first compressor 312 for compression, and then a part of the first working fluid enters the first condenser 311 for condensation, and the airflow that needs to be regenerated absorbs heat when passing through the condenser to achieve the first temperature rise. Another part of the first working fluid flowing out through the outlet of the first compressor 312 enters the first channel of the first intermediate heat exchanger 400. Under the action of the first intermediate heat exchanger 400, the second working fluid in the second channel absorbs heat from the first working fluid in the first channel; the second working fluid after absorbing heat flows into the second compressor 322 for compression, and then the second working fluid enters the second condenser 321 for condensation. The airflow that needs to be regenerated will absorb heat when passing through the second condenser 321, thereby achieving a second temperature rise.

[0074] When the gradient condensation heat pump system includes three heat pump systems, the three heat pump systems are respectively the first heat pump system 310, the second heat pump system 320 and the third heat pump system. The first intermediate heat exchanger 400 between the first heat pump system 310 and the second heat pump system 320 is recorded as the first intermediate heat exchanger A, and the first intermediate heat exchanger 400 between the second heat pump system 320 and the third heat pump system is recorded as the first intermediate heat exchanger B. The third working medium circulates in the third heat pump system. The working principles of the first heat pump system 310 and the second heat pump system 320 are the same as those of the first heat pump system 310 and the second heat pump system 320 in the above-mentioned embodiment, and will not be repeated here. The following focuses on the coordination relationship between the second heat pump system 320 and the third heat pump system. When in use, part of the second working fluid flowing out of the outlet of the second compressor 322 flows into the second condenser 321, and the other part flows into the first channel of the first intermediate heat exchanger B. Under the action of the first intermediate heat exchanger B, the third working fluid in the second channel of the first intermediate heat exchanger B absorbs heat from the second working fluid in the first channel; the third working fluid after absorbing heat flows into the second compressor 322 for compression, and then the second working fluid enters the third condenser for condensation. The airflow that needs to be regenerated will absorb heat when passing through the third condenser, thereby achieving the third heating.

[0075] In this embodiment, the gradient condensation heat pump system can realize multi-cascade compression and gradient condensation, which can be more conducive to increasing the regeneration temperature and achieving maximum energy saving.

[0076] In some embodiments of the present invention, the heat pump system for heating the airflow for the next time further includes a throttling device, which is located between the outlet of the lower condenser and the inlet of the second channel. For example, the throttling device of the second heat pump system 320 is located between the outlet of the second condenser 321 and the inlet of the second channel.

[0077] In some embodiments of the present invention, the rotary dehumidification system further includes a second intermediate heat exchanger 500 .

[0078] The second intermediate heat exchanger includes a liquid return pipe and a liquid inlet pipe.

[0079] The outlet of the first channel for circulating the first working medium is connected to the inlet of the liquid return pipe, and the outlet of the first condenser 311 is connected to the inlet of the liquid return pipe, and the outlet of the liquid return pipe is connected to the inlet of the evaporator 200 through the first throttling line.

[0080] The inlet of the liquid inlet pipe is connected to the outlet of the liquid return pipe through the second throttling pipeline, and the outlet of the liquid inlet pipe is connected to the inlet of the first compressor 312; the first working medium absorbing heat by evaporation in the liquid inlet pipe exchanges heat with the first working medium releasing heat by condensation in the liquid return pipe.

[0081] The second intermediate heat exchanger 500 is used to collect the first working medium cooled by the corresponding first intermediate heat exchanger 400 and the first working medium cooled by the first condenser 311 into the second intermediate heat exchanger 500 for supercooling, and then enter the evaporator 200 after throttling.

[0082] After absorbing heat, the first working medium in the liquid inlet pipe flows out from the outlet of the liquid inlet pipe and then flows into the first compressor 312. The above arrangement is more conducive to increasing the heating temperature of the first heat pump system 310 and saving energy.

[0083] Specifically, a throttling device is provided on the first throttling pipeline, and a throttling device is also provided on the second throttling pipeline.

[0084] In this embodiment, the first working medium can be subcooled by providing the second intermediate heat exchanger 500. After the subcooled first working medium returns to the evaporator 200, it can better absorb the heat in the air on the low-temperature dehumidification side.

[0085] In some embodiments of the present invention, the rotary dehumidification system includes a rotary wheel 100 and a gradient condensation heat pump system.

[0086] In some embodiments of the present invention, the rotary dehumidification system includes at least two rotary wheels 100 (for example, two rotary wheels 100, three rotary wheels 100 or four rotary wheels 100), at least two rotary wheels 100 are arranged in sequence along the flow direction of the airflow, and at least two gradient condensation heat pump systems are provided on the high temperature regeneration side. The evaporator 200 is located between the dehumidification areas of the two rotary wheels 100.

[0087] Specifically, the evaporator 200 may be disposed between any two wheels 100 .

[0088] In this embodiment, by providing at least two wheels 100, the dehumidification performance of the wheel dehumidification system can be improved.

[0089] In some embodiments of the present invention, the rotary dehumidification system includes at least two rotary wheels 100 (for example: two rotary wheels 100, three rotary wheels 100 or four rotary wheels 100), at least two rotary wheels 100 are arranged in sequence along the flow direction of the airflow, and at least two gradient condensation heat pump systems are provided on the high temperature regeneration side. The evaporator 200 is located between the dehumidification areas of the two rotary wheels 100. Each gradient condensation heat pump system is connected to the evaporator 200. The evaporator 200 is located between the dehumidification areas of the two rotary wheels 100. Specifically, the first heat pump system 310 of each gradient condensation heat pump system is connected to the same evaporator 200. In some alternative embodiments, at least two parallel evaporators 200 are provided between the dehumidification areas of the two rotary wheels 100, and the evaporator 200 corresponds to the gradient condensation heat pump system one by one. The first heat pump system 310 of each gradient condensation heat pump system is connected to a different evaporator 200.

[0090] In this embodiment, the first heat pump system 310 of the plurality of gradient condensing heat pump systems shares one evaporator 200, which can not only reduce production costs but also further reduce energy consumption. Therefore, this embodiment is conducive to better achieving the purpose of maximizing energy saving.

[0091] In some embodiments of the present invention, a steam heating device 700 is provided between the rotor 100 and the gradient condensation heat pump system for reheating the airflow heated by the gradient condensation heat pump system.

[0092] In this embodiment, the regeneration temperature can be further increased by providing a steam heating device 700 .

[0093] In some embodiments of the present invention, the first heat pump system 310 includes a plurality of first compressors 312, which are arranged in parallel. For example, the first heat pump system 310 includes two first compressors 312 arranged in parallel; or, the first heat pump system 310 includes three first compressors 312 arranged in parallel.

[0094] In this embodiment, by providing a plurality of first compressors 312 arranged in parallel, the heating temperature and heating efficiency of the first heat pump system 310 are improved.

[0095] In some alternative embodiments, the first heat pump system 310 may also include only one first compressor 312 .

[0096] In some embodiments of the present invention, Figure 1 As shown, the rotary dehumidification system includes two rotary wheels 100, a low-temperature dehumidification side and a high-temperature regeneration side. Two gradient condensation heat pump systems are provided on the high-temperature regeneration side. The gradient condensation heat pump system includes two heat pump systems, the two heat pump systems are respectively a first heat pump system 310 and a second heat pump system 320, and a first working medium circulates in the first heat pump system 310. A second working medium circulates in the second heat pump system 320. The first heat pump system 310 is used to heat the airflow for the first time, and the second heat pump system 320 is used to heat the airflow for the second time. A first intermediate heat exchanger 400 is provided between the first heat pump system 310 and the second heat pump system 320. A second intermediate heat exchanger 500 is provided between the first intermediate heat exchanger 400 and the evaporator 200. The evaporator 200 is located between the dehumidification areas of the two rotary wheels 100.

[0097] The low-temperature dehumidification side is provided with three coolers 600, namely the first cooler, the second cooler and the third cooler. Specifically, the two rotors 100 are the first-stage rotor and the second-stage rotor. The low-temperature dehumidification side is provided with the first cooler, the dehumidification area of ​​the first-stage rotor, the evaporator 200, the second cooler, the dehumidification area of ​​the second-stage rotor, and the third cooler in sequence along the air flow direction.

[0098] The first heat pump system 310 also includes two control valves 313, which are used to control the total flow of the working fluid in the heat pump system. Specifically, the two control valves 313 are respectively a first control valve and a second control valve. A first control valve is provided between the inlet of the first condenser 311 and the outlet of the first compressor 312; a second control valve is provided between the inlet of the first channel of the first intermediate heat exchanger 400 and the outlet of the first compressor 312.

[0099] The outdoor fresh air is pre-treated by the first surface cooler 600, and after the first cooling and dehumidification, it enters the first-stage rotor 100 dehumidifier unit for the first deep dehumidification. The low-humidity dry airflow after dehumidification and heating enters the evaporator 200 for the second cooling. The cooled dry airflow is divided into two airflows and enters different partitions of the second-stage rotor 100 respectively. One part of the airflow enters the dehumidification pre-regeneration area of ​​the second-stage rotor 100 to pre-regenerate the airflow; the other part of the airflow enters the dehumidification area of ​​the second-stage rotor 100 for the second deep dehumidification. The ultra-low humidity dry airflow after deep dehumidification and heating enters the third surface cooler 600 for the third cooling, and is finally sent to the drying room.

[0100] The airflow that needs to be regenerated is gradient condensed and heated by the gradient condensation heat pump system corresponding to the first-stage wheel 100 to become a high-temperature airflow, and enters the regeneration area of ​​the first-stage wheel 100 respectively, and the regeneration area of ​​the first-stage wheel 100 is heated and regenerated respectively. After regeneration, the exhaust air (regeneration air) is discharged from the regeneration port.

[0101] The airflow that needs to be regenerated is gradient condensed and heated by the gradient condensation heat pump system corresponding to the second-stage wheel 100 to become a high-temperature airflow, enters the regeneration area of ​​the second-stage wheel 100, and heats and regenerates the regeneration area of ​​the second-stage wheel 100. After regeneration, the exhaust air is discharged from the regeneration port.

[0102] The temperature of the air flow after heating by the first condenser 311 is 65°C, the temperature of the air flow after heating by the second condenser 321 is 130°C, and the temperature of the air flow after heating by the steam heating device 700 is 130°C.

[0103] like Figure 2-7 As shown, the present invention also provides a control method for the rotary dehumidification system described in any one of the above embodiments.

[0104] The control method comprises the following steps:

[0105] Step S100, obtaining the actual moisture content of the air at the outlet side of the dehumidification area of ​​the wheel 100.

[0106] Step S200, controlling the frequency of the compressor of each heat pump system at least according to the actual moisture content.

[0107] Specifically, through step S100, the actual dehumidification effect of the wheel 100 can be obtained. Through step S200, the frequency of the compressor of each heat pump system can be controlled according to the actual dehumidification effect of the wheel 100, which is conducive to achieving better dehumidification effect and maximizing energy saving of the system.

[0108] According to the actual moisture content of the air at the outlet side of the dehumidification area of ​​each wheel 100 , each heat pump system of the corresponding gradient condensation heat pump system is controlled to adjust the dehumidification amount of the dehumidification area of ​​each wheel 100 .

[0109] In this embodiment, the frequency of the compressors of each heat pump system is controlled by the actual moisture content of the air at the outlet side of the dehumidification area of ​​the wheel 100, which is conducive to balancing the dehumidification effect, regeneration temperature and system energy consumption. In other words, the present invention can better improve the overall energy saving of the system while preferably ensuring the dehumidification effect and regeneration effect.

[0110] like Figure 3 As shown, in some optional embodiments of the present invention, step S200, at least according to the actual moisture content, controls the frequency of the compressor of each heat pump system, including the following steps:

[0111] Step S201, when the actual humidity is continuously higher than the first preset humidity within the first preset time, the temperature of the air heated by each heat pump system is obtained and recorded as the first actual temperature.

[0112] Step S202: if each first actual temperature is lower than the respective first preset temperature, the frequency of the compressor of each heat pump system is increased.

[0113] Further, the first preset humidity content=target humidity content+deviation humidity content, wherein the deviation humidity content is greater than 0. The first preset temperature=set temperature value-deviation temperature value, wherein the deviation temperature value is greater than 0.

[0114] During the operation of the rotary dehumidification system, if the actual moisture content is continuously higher than the first preset moisture content within the first preset time, it means that the dehumidification capacity of the rotary wheel 100 does not meet the set requirement. If the first temperature corresponding to each heat pump system is lower than the first preset temperature at the same time, it means that the heating effect of each heat pump system on the airflow is not good. At this time, increasing the frequency of the compressor is conducive to increasing the regeneration temperature and also conducive to improving the dehumidification effect.

[0115] Furthermore, in some embodiments of the present invention, the first heat pump system 310 further includes a control valve 313, and the control valve 313 is used to control the total flow rate of the working medium in the heat pump system.

[0116] Specifically, the control valve 313 includes a first control valve and a second control valve. The first control valve is disposed between the inlet of the first condenser 311 and the outlet of the first compressor 312 ; the second control valve 313 is disposed between the inlet of the first channel of the first intermediate heat exchanger 400 and the outlet of the first compressor 312 .

[0117] like Figure 4 As shown, step S200, at least according to the actual moisture content, controls the frequency of the compressor of each heat pump system, including the following steps:

[0118] Step S201, when the actual humidity is continuously higher than the first preset humidity within the first preset time, the temperature of the air heated by each heat pump system is obtained and recorded as the first actual temperature.

[0119] Step S203 , if each first actual temperature is lower than the respective first preset temperature, the frequency of the compressor of each heat pump system is increased, and the opening of the control valve 313 is increased.

[0120] Specifically, "increasing the opening of the control valve 313" refers to increasing the opening of the first control valve and the second control valve to increase the total flow rate of the working fluid in the first heat pump system 310, thereby improving the heating effect of the first condenser 311 on the air flow to be regenerated, and at the same time improving the cooling effect of the evaporator 200 on the air on the low-temperature dehumidification side, thereby improving the dehumidification effect of the air.

[0121] In this embodiment, when the dehumidification capacity of the wheel 100 does not meet the set requirements and the heating effect of each heat pump system on the airflow is not good, increasing the frequency of the compressor and the opening of the control valve 313 at the same time is more conducive to increasing the regeneration temperature and also more conducive to improving the dehumidification effect.

[0122] In some embodiments of the present invention, a steam heating device 700 is provided between the rotor 100 and the gradient condensation heat pump system.

[0123] like Figure 3 and Figure 4 As shown, if each first actual temperature is less than the respective first preset temperature, at least the frequency of the compressor is increased, and then the following steps are also included:

[0124] Step S204, when the frequencies of the compressors are increased to the maximum frequency, the air flow temperature at the air inlet side of the regeneration area of ​​the runner 100 is obtained and recorded as the inlet temperature.

[0125] Step S205, if the inlet temperature is continuously lower than the target temperature within the second preset time, the steam heating device 700 is turned on, and the steam heating device 700 is turned off when the inlet temperature is higher than or equal to the target temperature.

[0126] Specifically, the second preset time can be set as needed. For example, the second preset time can be 3 minutes, 4 minutes, 5 minutes, etc.

[0127] In this embodiment, the steam heating device 700 is provided to increase the regeneration temperature, which is beneficial to improving the heating efficiency. In addition, when the effect of increasing the regeneration temperature by controlling each heat pump system alone is not good, the heating effect can be improved by adjusting the steam heating device 700, which is more conducive to reducing energy consumption and thus more conducive to achieving the purpose of maximizing energy saving.

[0128] In some embodiments of the present invention, controlling the frequency of the compressor of each heat pump system at least according to the actual moisture content comprises the following steps:

[0129] Step S201, when the actual humidity is continuously higher than the first preset humidity within the first preset time, the temperature of the air heated by each heat pump system is obtained and recorded as the first actual temperature.

[0130] Step S206, if each first actual temperature is lower than its respective first preset temperature, while the system pressure and temperature are within the safety range, the compressor operating frequency of each heat pump system is increased by 10% (the frequency increase value can be set as needed) in each sampling cycle, and the corresponding valve opening is opened until each compressor runs at full frequency.

[0131] In the above embodiments, the first preset time can be set as needed. For example, the first preset time can be 3 minutes, 4 minutes, 5 minutes, etc.

[0132] like Figure 5 As shown, in some embodiments of the present invention, the frequency of the compressor of each heat pump system is controlled at least according to the actual moisture content, including the following steps:

[0133] Step S211, when the actual moisture content is continuously less than the second preset moisture content within the third preset time, reducing the frequency of the compressor of each heat pump system.

[0134] Step S212, when the actual moisture content is less than or equal to the second preset moisture content and less than or equal to the first preset moisture content, stop reducing the frequency of the compressor; wherein the first preset moisture content is greater than the second preset moisture content.

[0135] Specifically, the third preset time can be set as needed, for example, the third preset time can be 3 minutes, 4 minutes or 5 minutes, etc. The first preset moisture content = target moisture content + deviation moisture content; the second preset moisture content = target moisture content - deviation moisture content, and the deviation moisture content is greater than 0.

[0136] When the actual moisture content is continuously less than the second preset moisture content within the third preset time, it indicates that the dehumidification capacity of the rotor 100 is excessive. At this time, at least the frequency of the compressor is reduced. On the one hand, it can not only reduce the heating capacity of each condenser for the air flow to be regenerated, but also reduce the cooling effect of the evaporator 200 on the low-temperature dehumidification side air, thereby reducing the dehumidification capacity. On the other hand, it is more conducive to achieving the purpose of maximizing energy saving.

[0137] In some embodiments of the present invention, the first heat pump system 310 further includes a control valve 313, which is used to control the total flow of the working medium in the heat pump system. Specifically, the control valve 313 includes a first control valve 313 and a second control valve 313. The first control valve 313 is provided between the inlet of the first condenser 311 and the outlet of the first compressor 312; the second control valve 313 is provided between the inlet of the first channel of the first intermediate heat exchanger 400 and the outlet of the first compressor 312.

[0138] like Figure 6 As shown, controlling the frequency of the compressor of each heat pump system at least according to the actual moisture content comprises the following steps:

[0139] Step S213, when the actual moisture content is continuously less than the second preset moisture content within the third preset time, the frequency of the compressor of each heat pump system is reduced, and the opening degree of the control valve 313 is reduced.

[0140] Step S214, when the actual moisture content is less than or equal to the second preset moisture content and less than or equal to the first preset moisture content, stop reducing the frequency of the compressor; wherein the first preset moisture content is greater than the second preset moisture content.

[0141] Specifically, "reducing the opening of the control valve 313" means reducing the opening of the first control valve 313 and the second control valve 313 to reduce the total flow rate of the working fluid in the first heat pump system 310, thereby reducing the heating effect of the first condenser 311 on the air flow to be regenerated, and at the same time reducing the cooling effect of the evaporator 200 on the air on the low-temperature dehumidification side, thereby reducing the dehumidification effect of the air.

[0142] In this embodiment, when the dehumidification capacity of the wheel 100 is excessive, the frequency of the compressor and the opening of the control valve 313 are reduced simultaneously, which can meet the dehumidification needs while being more conducive to achieving the goal of maximizing energy saving.

[0143] In some embodiments of the present invention, a steam heating device 700 is provided between the rotor 100 and the gradient condensation heat pump system.

[0144] like Figure 7 As shown, controlling the frequency of the compressor of each heat pump system at least according to the actual moisture content comprises the following steps:

[0145] Step S215, when the actual moisture content is continuously less than the second preset moisture content within the third preset time, the heating power of the steam heating device 700 is reduced or the steam heating device 700 is turned off, and the frequency of the compressor is reduced.

[0146] Step S216, when the actual moisture content is less than or equal to the second preset moisture content and less than or equal to the first preset moisture content, stop reducing the frequency of the compressor, and maintain or increase the heating power of the steam heating device 700 or turn on the steam heating device 700.

[0147] The first preset moisture content is greater than the second preset moisture content.

[0148] Furthermore, in step S215, while the frequency of the compressor is reduced, the opening of the control valve 313 is reduced.

[0149] In this embodiment, when the dehumidification capacity of the rotary wheel 100 is excessive, it is more conducive to reducing energy consumption, thereby more conducive to achieving the purpose of maximizing energy saving. It is preferred to reduce the heating power of the steam heating device 700 or turn off the steam heating device 700.

[0150] In some embodiments of the present invention, the frequency of the compressor of each heat pump system is controlled at least according to the actual moisture content, including the following steps: Step S220, when the actual moisture content is less than or equal to the second preset moisture content and less than or equal to the first preset moisture content within a fourth preset time period, maintain the existing frequency of the compressor of each heat pump system.

[0151] When the actual moisture content is less than or equal to the second preset moisture content and less than or equal to the first preset moisture content within the fourth preset time, it means that the dehumidification of the wheel 100 meets the requirement. The fourth preset time can be set as needed, for example, the fourth preset time can be 3 minutes, 4 minutes or 5 minutes, etc.

[0152] In some embodiments of the present invention, the rotary dehumidification system further includes a plurality of surface coolers 600, which are arranged on the low-temperature dehumidification side and are arranged in sequence along the flow direction of the air.

[0153] The control method further comprises the following steps:

[0154] Step S300, obtaining the temperature at the outlet side of each cooler 600, and recording it as the actual outlet temperature.

[0155] Step S400, controlling the water valves of each surface cooler 600 according to the actual outlet temperature.

[0156] Specifically, the actual outlet temperature of each cooler 600 is compared with the corresponding set outlet temperature, and the water valve of each cooler 600 is controlled according to the comparison result.

[0157] In this embodiment, the above arrangement facilitates rapid adjustment of the dehumidification capacity of the wheel 100 .

[0158] In some embodiments of the present invention, step S400, controlling the water valve of each cooler 600 according to the actual outlet temperature, includes:

[0159] Step S401: If each actual outlet temperature is greater than the corresponding first set outlet temperature within the fifth preset time, the water valve opening of each cooler 600 is increased. For example, the water valve is opened by 10% in each sampling period until the water valve is fully opened. The first set outlet temperature = target outlet temperature + T.

[0160] Step S402: If each actual outlet temperature is less than the corresponding second set outlet temperature within the fifth preset time, the water valve opening of each cooler 600 is reduced. For example, the water valve opening is reduced by 10% in each sampling period until the actual outlet temperature meets the target outlet temperature ±T deviation for 3 minutes. The second set outlet temperature = target outlet temperature - T.

[0161] Step S403: if each actual outlet temperature is greater than or equal to the corresponding second set outlet temperature and less than or equal to the corresponding first set outlet temperature within the fifth preset time, the water valve opening of each cooler 600 is maintained.

[0162] Specifically, the fifth preset time is 3 minutes, and may also be 4 minutes or 5 minutes. In other words, the fifth preset time may be set as required.

[0163] This embodiment provides a method for scientifically controlling the water valve of the surface cooler 600.

[0164] Multiple exemplary embodiments of the present invention, however, without departing from the spirit and scope of the present invention, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the content disclosed in the present invention. Therefore, the scope of the present invention should be understood and identified as covering all these other variations or modifications.

Claims

1. A rotary dehumidification system, characterized in that: include: at least one rotor, the rotor comprising a regeneration region and a dehumidification region; A low-temperature dehumidification side, wherein the low-temperature dehumidification side is provided with the dehumidification area and an evaporator, and a first working medium flows in the evaporator; On the high-temperature regeneration side, at least one gradient condensation heat pump system is provided on the high-temperature regeneration side, and the gradient condensation heat pump system corresponds to the rotor one-to-one, and is used to perform gradient heating on the airflow before entering the regeneration area of ​​each rotor; the gradient condensation heat pump system includes a plurality of heat pump systems for heating the airflow in sequence, wherein the working fluid of the heat pump system for heating the airflow for the last time is the upper working fluid, and the working fluid of the heat pump system for heating the airflow for the next time is the lower working fluid, and the lower working fluid absorbs heat during evaporation and exchanges heat with the upper working fluid that releases heat during condensation through the first intermediate heat exchanger; the heat pump system for heating the airflow for the first time uses the first working fluid flowing out of the evaporator to heat the airflow for the first time.

2. The rotary dehumidification system according to claim 1, characterized in that: The first intermediate heat exchanger comprises a first channel and a second channel, the first channel has an upper-level working medium flowing therein, and the second channel has a lower-level working medium; Each of the heat pump systems comprises a condenser and a compressor, wherein the condenser is used to heat the air flow; The condenser and compressor of the heat pump system for heating the airflow for the last time are recorded as the upper condenser and the upper compressor; the upper compressor is used to compress the upper working medium, and the outlet of the upper compressor is connected to the upper condenser; The condenser and the compressor of the heat pump system for performing the next temperature increase on the airflow are recorded as the lower-stage condenser and the lower-stage compressor; the lower-stage compressor is used to compress the lower-stage working medium, the inlet of the lower-stage compressor is connected to the second channel corresponding to the first intermediate heat exchanger, and the outlet of the lower-stage compressor is connected to the lower-stage condenser; The condenser and compressor of the heat pump system for heating the airflow for the first time are referred to as the first condenser and the first compressor; the first compressor is used to compress the first working fluid; the inlet of the first compressor is connected to the evaporator, and the outlet of the first compressor is connected to the first condenser.

3. The rotary dehumidification system according to claim 2, characterized in that: The rotary dehumidification system also includes a second intermediate heat exchanger; The second intermediate heat exchanger comprises: a liquid return pipe, wherein the outlet of the first channel through which the first working medium flows is connected to the inlet of the liquid return pipe, and the outlet of the first condenser is connected to the inlet of the liquid return pipe, and the outlet of the liquid return pipe is connected to the inlet of the evaporator through a first throttling pipeline; a liquid inlet pipe, wherein the inlet of the liquid inlet pipe is connected to the outlet of the liquid return pipe through a second throttling pipeline, and the outlet of the liquid inlet pipe is connected to the inlet of the first compressor; the first working medium absorbing heat during evaporation in the liquid inlet pipe performs heat exchange with the first working medium releasing heat during condensation in the liquid return pipe; The heat pump system for heating the airflow for the first time further comprises a control valve, which is used to control the total flow rate of the working fluid in the heat pump system.

4. The rotary dehumidification system according to claim 1, characterized in that: The rotary dehumidification system comprises at least two rotary wheels, at least two rotary wheels are arranged in sequence along the flow direction of the airflow, and at least two gradient condensation heat pump systems are provided on the high-temperature regeneration side; Each gradient condensing heat pump system is connected to the evaporator; The evaporator is located between the dehumidification areas of the two wheels.

5. The rotary dehumidification system according to claim 1, characterized in that: A steam heating device is provided between the rotor and the gradient condensation heat pump system, for reheating the airflow heated by the gradient condensation heat pump system.

6. A control method for a rotary dehumidification system according to any one of claims 1 to 5, characterized in that: include: Obtaining the actual moisture content of the air at the outlet side of the dehumidification area of ​​the rotor; The frequency of the compressor of each of the heat pump systems is controlled at least according to the actual moisture content.

7. The control method of the rotary dehumidification system according to claim 6, characterized in that: Controlling the frequency of the compressors of each of the heat pump systems at least according to the actual moisture content comprises: When the actual humidity content is continuously higher than the first preset humidity content within the first preset time, the temperature of the air heated by each of the heat pump systems is obtained and recorded as the first actual temperature; If each of the first actual temperatures is lower than the respective first preset temperature, then at least the frequency of the compressor of each of the heat pump systems is increased.

8. The control method of the rotary dehumidification system according to claim 7, characterized in that: A steam heating device is provided between the rotor and the gradient condensation heat pump system; If each of the first actual temperatures is lower than the respective first preset temperatures, at least the frequency of the compressor of each of the heat pump systems is increased, and then, the method further includes: When the frequencies of the compressors are all increased to the maximum frequency, the air flow temperature at the air inlet side of the regeneration area of ​​the runner is obtained and recorded as the inlet temperature; If the inlet temperature is continuously lower than the target temperature within the second preset time, the steam heating device is turned on until the inlet temperature is greater than or equal to the target temperature, and then the steam heating device is turned off.

9. The control method of the rotary dehumidification system according to claim 6, characterized in that: Controlling the frequency of the compressors of each of the heat pump systems at least according to the actual moisture content comprises: When the actual moisture content is continuously less than the second preset moisture content within a third preset time, at least reducing the frequency of the compressor of each of the heat pump systems; When the actual moisture content is less than or equal to the second preset moisture content and less than or equal to the first preset moisture content, stopping reducing the frequency of the compressor; Wherein, the first preset moisture content is greater than the second preset moisture content.

10. The control method of the rotary dehumidification system according to claim 6, characterized in that: A steam heating device is provided between the rotor and the gradient condensation heat pump system; Controlling the frequency of the compressors of each of the heat pump systems at least according to the actual moisture content comprises: When the actual moisture content is continuously less than the second preset moisture content within the third preset time, reducing the heating power of the steam heating device or shutting down the steam heating device, and reducing the frequency of the compressor; When the actual moisture content is less than or equal to the second preset moisture content and less than or equal to the first preset moisture content, stop reducing the frequency of the compressor, and maintain or increase the heating power of the steam heating device or turn on the steam heating device; Wherein, the first preset moisture content is greater than the second preset moisture content.

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