A heat pump drying system with direct humidity regulation and its operation method

Abstract

The present invention discloses a heat pump drying system with direct humidity regulation and its operation method, including a heat pump subsystem composed of a compressor, two heat storage condensers, a condenser, a liquid storage device, a throttle valve, an evaporator, and a plurality of solenoid valves, and an air subsystem composed of a fan, a drying box, two dehumidification boxes, two total heat exchangers, two heat pipe heat exchangers, and a required air volume regulating valve. The present invention directly utilizes the exhaust heat of the compressor to regenerate the hygroscopic material, and the heating and dehumidification of the dry air are respectively completed by the heat pump and the solid dehumidification material, thereby overcoming the problem of mismatch between the cold and heat in the operation of the heat pump system, improving the drying speed, and recovering the condensation waste heat and the tail gas waste heat at the same time, improving the overall operation efficiency of the system, and also having the characteristics of convenient adjustment and one machine with multiple uses.

Description

Technical Field

[0001] The invention relates to a heat pump drying system with direct humidity regulation and an operation method thereof, belonging to the technical field of heat pump drying. Background Art

[0002] Product drying in the industrial and agricultural production process is a high energy consumption process. Heat pump drying equipment has the advantages of recycling waste heat and convenient humidity control. It uses the reverse Carnot principle to absorb the heat of the surrounding environment or the exhaust air of the drying box and transfer it to the drying room to increase the temperature of the drying room. When adjusting humidity, heat pump drying generally uses a built-in evaporator to cool and dehumidify the dry hot air.

[0003] The following problems still exist for the closed heat pump drying cycle. First, the dry air enters the drying box to dry the material after being heated by the condenser, transfers heat to the material and takes away the moisture of the material, and flows out of the drying box after the temperature drops. In order to remove moisture from the air, the heat pump evaporation temperature needs to be reduced to below the dew point temperature, corresponding to a lower evaporation temperature, and then continues to dry after being heated by the condenser. In this process, the dry air undergoes a heating, cooling and dehumidification process, and there is a waste of heat offset by cooling first and then heating, and the operating evaporation temperature is low, resulting in a significant reduction in the heat pump performance coefficient. Taking the drying temperature of 60°C and the relative humidity of 15% as an example, considering a 5°C temperature difference, the temperature of the dry air flowing out of the drying box is 55°C and the relative humidity is 20.9%. In order to dehumidify, the 55°C air needs to be cooled to 25.7°C, and the required cooling heat exceeds 37.6kJ / kg. The temperature difference from the end point of dehumidification to the drying point is 36°C. This large cooling heat demand requires a larger evaporator or a lower evaporation temperature to achieve a temperature reduction of nearly 31°C, resulting in an overly large evaporator design area or a low evaporation temperature for the heat pump to operate. Otherwise, the dehumidification requirements cannot be met, which increases the flow resistance and directly reduces the heat pump performance coefficient. The large temperature difference demand for reheating will also lead to an overly large condenser area or a high condensation temperature, which will also reduce the heat pump performance coefficient, and even be comparable to the efficiency of electric heating. Users cannot feel the high efficiency and energy saving performance of heat pump drying. Second, in traditional heat pump drying equipment, in order to simultaneously meet the dehumidification and heating of dry air, a condenser needs to be set up to discharge excess heat, otherwise the heating temperature will be out of control, and this setting will cause additional heat waste. Third, the drying temperature of heat pump drying is relatively low (40~80°C range), which leads to a slow dehydration speed in the later stage of drying, a long overall drying time, and even product deterioration. For this reason, it is necessary to innovate the design of the heat pump drying system to meet the dehumidification requirements. Summary of the invention

[0004] The object of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide a heat pump drying system with direct humidity regulation and an operating method thereof.

[0005] The technical solution provided by the present invention is as follows: a heat pump drying system with direct humidity regulation, characterized in that it comprises a heat pump subsystem and a dry air subsystem;

[0006] The heat pump subsystem includes a compressor, the outlet of the compressor is respectively connected to the inlet of the sixth solenoid valve, the inlet of the first solenoid valve and the inlet of the second solenoid valve, the outlet of the sixth solenoid valve is connected to the working fluid inlet of the condenser, the outlet of the first solenoid valve is connected to the inlet of the first heat storage condenser, the outlet of the first heat storage condenser is connected to the inlet of the third solenoid valve, the outlet of the second solenoid valve is connected to the inlet of the second heat storage condenser, the outlet of the second heat storage condenser is connected to the inlet of the fourth solenoid valve, the outlet of the fourth solenoid valve is respectively connected to the outlet of the third solenoid valve, the working fluid inlet of the condenser, the outlet of the sixth solenoid valve and the inlet of the seventh solenoid valve, the working fluid outlet of the condenser is connected to the outlet of the seventh solenoid valve and the inlet of the liquid reservoir, the outlet of the liquid reservoir is connected to the inlet of the fifth solenoid valve, the outlet of the fifth solenoid valve is connected to the inlet of the throttle valve, the outlet of the throttle valve is connected to the inlet of the evaporator, and the outlet of the evaporator is connected to the inlet of the compressor;

[0007] The dry air subsystem includes a fan, which is placed in an air duct and connected to the inlet of a drying box through the air duct. The air duct at the outlet of the drying box is divided into three branches. The lower branch of the three branches is connected to the inlet of a first air volume regulating valve through the air duct, and the outlet of the first air volume regulating valve is connected to the inlet of a first dehumidification box and the outlet of a fourth air volume regulating valve through the air duct. The outlet of the first dehumidification box is connected to the inlet of the evaporation section of the first heat pipe heat exchanger, and the outlet of the evaporation section of the first heat pipe heat exchanger is respectively connected to the inlet of a sixth air volume regulating valve and the inlet of an eighth air volume regulating valve. The inlet of a fresh air passage of the first total heat exchanger is connected to the environment, the outlet of the fresh air passage of the first total heat exchanger is connected to the inlet of the fourth air volume regulating valve, the outlet of the sixth air volume regulating valve is connected to the inlet of an exhaust passage of the first total heat exchanger, and the outlet of the exhaust passage of the first total heat exchanger leads to the outdoor environment; the upper branch of the three branches is connected to the inlet of a second air volume regulating valve through the air duct, and the outlet of the second air volume regulating valve is respectively connected to the inlet of a second dehumidification box and the outlet of a fifth air volume regulating valve through the air duct. , the outlet of the second dehumidification box is connected to the inlet of the evaporation section of the second heat pipe heat exchanger, the outlet of the evaporation section of the second heat pipe heat exchanger is respectively connected to the inlet of the seventh air volume regulating valve and the inlet of the ninth air volume regulating valve, the inlet of the fresh air passage of the second total heat exchanger is connected to the environment, the outlet of the fresh air passage of the second total heat exchanger is connected to the inlet of the fifth air volume regulating valve, the outlet of the seventh air volume regulating valve is connected to the inlet of the exhaust passage of the second total heat exchanger, and the outlet of the exhaust passage of the second total heat exchanger leads to the outdoor environment; the middle branch of the three branches is connected to the inlet of the third air volume regulating valve through the air duct, the outlet of the third air volume regulating valve is connected to the inlet of the condensation section of the second heat pipe heat exchanger, the outlet of the condensation section of the second heat pipe heat exchanger is connected to the inlet of the condensation section of the first heat pipe heat exchanger, and the outlet of the condensation section of the first heat pipe heat exchanger is respectively connected to the outlet of the eighth air volume regulating valve and the outlet of the ninth air volume regulating valve; the outlet of the eighth air volume regulating valve and the outlet of the ninth air volume regulating valve are connected to the gas inlet of the condenser through the air duct, and the gas outlet of the condenser is connected to the inlet of the drying box through the air duct;

[0008] The first heat storage condenser and the second heat storage condenser are respectively built in the first dehumidification box and the second dehumidification box, and solid moisture absorbing materials are placed on the first heat storage condenser and the second heat storage condenser.

[0009] Furthermore, the first heat storage condenser and the second heat storage condenser are both coil-type heat exchangers with heat storage medium.

[0010] Furthermore, the heat storage medium is an organic phase change heat storage material or an inorganic hydrated salt phase change heat storage material.

[0011] Furthermore, the heat storage medium is paraffin or zinc nitrate.

[0012] Furthermore, the condenser is a fin-tube or plate-fin air-cooled heat exchanger, and the evaporator is a fin-tube or plate-fin air-cooled heat exchanger.

[0013] Furthermore, the first total heat exchanger and the second total heat exchanger are total heat exchangers with built-in fans.

[0014] Furthermore, the first heat pipe heat exchanger and the second heat pipe heat exchanger are heat pipe type heat exchangers, which contain a plurality of heat pipes inside, and the heat pipes are normal temperature heat pipes.

[0015] Furthermore, the solid hygroscopic material is one of silica gel or calcium chloride.

[0016] A method for operating a heat pump drying system with direct humidity control, characterized in that it includes a drying operation without dehumidification mode, the sixth solenoid valve in the heat pump subsystem is opened, and the first solenoid valve, the second solenoid valve and the seventh solenoid valve are closed; the refrigerant medium is compressed by the compressor and becomes a high-temperature and high-pressure gas, enters the condenser through the sixth solenoid valve, and becomes a high-temperature and high-pressure liquid after heat exchange with air in the condenser, enters the liquid storage device, and then enters the throttle valve through the fifth solenoid valve, and becomes a low-temperature and low-pressure gas after throttling by the throttle valve and flows into the evaporator, absorbs heat in the evaporator and is completely gasified, and then enters the compressor to continue to complete the next cycle; the third air volume regulating valve in the dry air subsystem is opened, and the remaining first air volume regulating valve, second air volume regulating valve, fourth air volume regulating valve, fifth air volume regulating valve, sixth air volume regulating valve, seventh air volume regulating valve, eighth air volume regulating valve, and ninth air volume regulating valve are all closed; driven by the fan, the dry air is heated by the condenser, enters the drying box for drying, takes away the moisture of the material, enters the condenser again after passing through the third air volume regulating valve, and repeats the above cycle after heating.

[0017] An operating method of a heat pump drying system with direct humidity control, characterized in that it includes a drying operation dehumidification mode, in which the sixth solenoid valve in the heat pump subsystem is closed, and at least one of the first solenoid valve and the second solenoid valve is opened; when the drying air temperature meets the drying set temperature of the material, the seventh solenoid valve is opened, otherwise the seventh solenoid valve is closed; when the first solenoid valve is opened, the refrigerant medium is compressed by the compressor and becomes a high-temperature and high-pressure gas, enters the first heat storage condenser through the first solenoid valve, releases the sensible heat of the compressor exhaust, and then enters the condenser through the third solenoid valve; when the second solenoid valve is opened, the high-temperature and high-pressure gas discharged from the compressor enters the second heat storage condenser through the second solenoid valve, releases the sensible heat of the compressor exhaust After the sensible heat of the gas is released, it enters the condenser through the fourth solenoid valve; the exhaust gas of the compressor releases heat in the first heat storage condenser and the second heat storage condenser to heat the heat storage phase change medium therein first, and then transfers the heat to the solid hygroscopic material to evaporate the water therein; if the dry air temperature is lower than the drying set temperature of the material, the seventh solenoid valve is closed, and the working fluid enters the condenser and exchanges heat with the air to become a high-temperature and high-pressure liquid, and enters the liquid storage tank; otherwise, the seventh solenoid valve is opened, and the refrigerant directly enters the liquid storage tank; then it enters the throttle valve through the fifth solenoid valve, and after throttling by the throttle valve, it becomes a low-temperature and low-pressure gas and flows into the evaporator, absorbs heat in the evaporator and is completely vaporized, and then enters the compressor to continue to complete the next cycle;

[0018] At least one of the upper branch or the lower branch in the dry air subsystem is opened, and the third air volume regulating valve is closed or partially opened;

[0019] When the lower branch is opened, the dry air is dehumidified through the lower branch, and the upper branch performs dehumidification material heating and regeneration operation; at this time, the first air volume regulating valve, the fifth air volume regulating valve, the seventh air volume regulating valve and the eighth air volume regulating valve are all opened, and the second air volume regulating valve, the fourth air volume regulating valve, the sixth air volume regulating valve and the ninth air volume regulating valve are all closed; the sixth solenoid valve and the seventh solenoid valve in the heat pump subsystem are closed, and the second solenoid valve is opened; when the second solenoid valve is opened, the second heat storage condenser and the heat storage medium therein heat the solid hygroscopic material, evaporate the moisture therein, and complete the regeneration of the hygroscopic material; driven by the fan, the dry air is heated by the condenser and then enters the drying box for drying, taking away the moisture of the material, and all or part of the air enters the first dehumidification box through the first air volume regulating valve, and the dehumidification material in the first dehumidification box removes the moisture in the air. After the air absorbs moisture, its temperature rises and the flow After exiting the first dehumidifier box, it enters the evaporation section of the first heat pipe heat exchanger and transfers heat to the working medium in the evaporation section. After the working medium is vaporized, it rises and enters the condensation section of the first heat pipe heat exchanger, releasing heat to the air in the middle branch, thereby realizing heat recovery; the dry air flows out of the evaporation section of the first heat pipe heat exchanger and then flows out through the eighth air volume regulating valve; when only part of the air passes through the first air volume regulating valve, the other part of the air flows out after passing through the third air volume regulating valve, merges with the air flowing out of the eighth air volume regulating valve, and then enters the condenser, repeating the above cycle after heating; the outdoor air enters through the fresh air passage of the second total heat exchanger, and then enters the second dehumidifier box through the fifth air volume regulating valve to take away the moisture evaporated by the hygroscopic material, enters the evaporation section of the second heat pipe heat exchanger after releasing heat, and then flows into the exhaust passage inlet of the second total heat exchanger through the seventh air volume regulating valve, and is discharged to the outdoor environment after releasing heat, thereby completing the regeneration of the hygroscopic material;

[0020] When the upper branch is opened, the dry air is dehumidified through the upper branch, and the lower branch performs dehumidification material heating and regeneration operation; at this time, the second air volume regulating valve, the fourth air volume regulating valve, the sixth air volume regulating valve and the ninth air volume regulating valve are all opened, and the first air volume regulating valve, the fifth air volume regulating valve, the seventh air volume regulating valve and the eighth air volume regulating valve are all closed; the sixth solenoid valve in the heat pump subsystem is closed and the first solenoid valve is opened; when the first solenoid valve is opened, the first heat storage condenser and the heat storage medium therein heat the solid hygroscopic material to evaporate the moisture therein and complete the regeneration of the hygroscopic material; driven by the fan, the dry air is heated by the condenser and then enters the drying box for drying, taking away the moisture of the material, and all or part of the air enters the second dehumidification box through the second air volume regulating valve, and the dehumidification material in the second dehumidification box removes the moisture in the air, and the air absorbs moisture After the temperature rises and flows out of the second dehumidification box, it enters the evaporation section of the second heat pipe heat exchanger, transfers the heat to the working medium in the evaporation section, and the working medium rises and enters the condensation section of the second heat pipe heat exchanger after vaporization, releasing heat to the air in the middle branch, thereby realizing heat recovery; after the dry air flows out of the evaporation section of the second heat pipe heat exchanger, it flows out through the ninth air volume regulating valve; when only part of the air passes through the second air volume regulating valve, the other part of the air flows out after the third air volume regulating valve, merges with the air flowing out of the ninth air volume regulating valve, and then enters the condenser, repeating the above cycle after heating; the outdoor air enters through the fresh air passage of the first total heat exchanger, enters the first dehumidification box through the fourth air volume regulating valve, takes away the moisture evaporated from the hygroscopic material, flows into the inlet of the exhaust passage of the first total heat exchanger through the sixth air volume regulating valve, is discharged to the outdoor environment after releasing heat, and completes the regeneration of the hygroscopic material.

[0021] The system of the present invention includes a heat pump subsystem and an air subsystem, wherein the heat pump subsystem includes a compressor, two heat storage condensers, a condenser, a liquid storage tank, a throttle valve, an evaporator, and several solenoid valves; the dry air subsystem includes a fan, a drying box, two dehumidification boxes, two total heat exchangers, two heat pipe heat exchangers, and a required air volume regulating valve, etc. The heat pump subsystem provides heating heat for the temperature rise of dry air and the regeneration of solid hygroscopic materials, meets the temperature and humidity requirements of material drying, directly uses the high-temperature exhaust sensible heat of the compressor for the dehydration of hygroscopic materials, and provides heat pipe heat exchangers to recover the heat of the temperature rise of air after passing through the hygroscopic materials, reduces the loss of heat conversion and transfer, and introduces efficient control of temperature and humidity. The present invention completes the heating and dehumidification of dry air by heat pumps and solid dehumidification materials respectively, overcoming the problem of mismatch of cold and heat in system operation caused by the heat pump condenser and evaporator realizing heating and dehumidification respectively.

[0022] The beneficial effects of the present invention are as follows: first, the solid dehumidification material is used to ensure low humidity conditions for heat pump drying, thereby increasing the heat pump drying speed. The system of the present invention utilizes the high-temperature gas of the heat pump refrigerant discharged from the compressor to condense in two heat storage condensers, releasing heat to the phase change material and the hygroscopic material, so that the material can quickly remove moisture, and continue to absorb moisture in the dry air after regeneration to obtain the lower relative humidity required for drying. The introduction of the heat storage condenser makes full use of the sensible heat of the heat pump exhaust, avoids heat waste, and can also achieve temporary storage of heat. At the same time, since the temperature of the dry air heated by the heat pump is usually in the range of 40 to 80°C, and its temperature range is relatively low, this dehumidification method ensures the low humidity requirements required for heat pump drying, maintains a high water vapor partial pressure difference between the dry air and the material, has a greater dehumidification capacity, and improves the drying speed of the heat pump drying, especially in the later stage of drying.

[0023] Secondly, the moisture of the dry air is removed by solid hygroscopic materials instead of using the heat pump evaporator, thereby reducing the impact of dehumidification on the operating conditions and efficiency of the heat pump. In the present invention, the hygroscopic materials in the first dehumidification box or the second dehumidification box are used to remove the moisture of the dry air, and the evaporator dehumidification method commonly used in heat pump drying is not used. A higher evaporation temperature can be obtained, the evaporator and condenser area can be reduced, the initial investment in the evaporator and condenser equipment can be reduced, and the heat exchange efficiency of the evaporator and condenser can be improved. The contradiction of the mismatch between the heating and dehumidification heat requirements in the operation of the heat pump is avoided, and the operating stability and reliability of the equipment are improved, thereby improving the performance coefficient of the heat pump system and giving full play to the advantages of high efficiency and energy saving of the heat pump.

[0024] Thirdly, in the system of the present invention, the first dehumidification box or the second dehumidification box is used to dehumidify the dry air in turn, thereby ensuring the continuous and uninterrupted operation of the heat pump drying.

[0025] Fourthly, the system of the present invention uses the first total heat exchanger and the second total heat exchanger to recover the waste heat of the exhaust gas regenerated by the hygroscopic material and heat the outdoor fresh air. In addition, the first heat pipe heat exchanger and the second heat pipe heat exchanger are used to recover the heat after the temperature rise of the hygroscopic material dehumidification, which further realizes the full utilization of the waste heat and improves the overall operation efficiency of the system.

[0026] Finally, the present invention has the advantages of convenient adjustment and one machine with multiple uses. The system adopts a condenser and two heat storage condensers arranged in series, and uses the sixth solenoid valve, the second solenoid valve and the air volume regulating valve and other components to make full use of the high-temperature compressor exhaust to obtain a higher regeneration temperature, ensure the heating demand, and meet the regeneration temperature requirements of the solid hygroscopic material; by opening the seventh solenoid valve bypassing the condenser, the heat storage operation can be realized, and the refrigerant exhaust from the compressor enters the first heat storage condenser and the second heat storage condenser through the first solenoid valve and the second solenoid valve respectively, and heat is stored for dehydration and regeneration of the solid hygroscopic material; closing the seventh solenoid valve, the refrigerant not only enters the first heat storage condenser and the second heat storage condenser but also continues to flow into the condenser to release heat, realizing heating and heat storage at the same time; the heat pump dehumidification and drying operation dehumidification mode and the drying operation without dehumidification mode can be switched, which is beneficial to ensure the multi-mode operation of the unit; the functions of introducing fresh air and dehumidification are realized by opening the fourth air volume regulating valve, the fifth air volume regulating valve, the sixth air volume regulating valve or the seventh air volume regulating valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 It is a structural schematic diagram of the heat pump drying system with direct humidity regulation of the present invention;

[0029] Figure 2 It is a structural schematic diagram of the heat storage condenser of the present invention. DETAILED DESCRIPTION

[0030] The specific implementation of the present invention is described in detail below with reference to the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0031] like Figure 1As shown, a heat pump drying system with direct humidity control includes a heat pump subsystem and a dry air subsystem. The heat pump subsystem includes a compressor 1, a first heat storage condenser 2-1, a second heat storage condenser 2-2, a condenser 3, a liquid storage tank 4, a fifth solenoid valve 5, a throttle valve 6, an evaporator 7, a sixth solenoid valve 8, a first solenoid valve 9-1, a second solenoid valve 9-2, a third solenoid valve 9-3, a fourth solenoid valve 9-4, and a seventh solenoid valve 20; the dry air subsystem includes a fan 10, a drying box 14, a first dehumidification box 15-1, a second dehumidification box 15-2, a first full Heat exchanger 16-1, second total heat exchanger 16-2, first air volume regulating valve 17-1, second air volume regulating valve 17-2, third air volume regulating valve 17-3, fourth air volume regulating valve 17-4, fifth air volume regulating valve 17-5, sixth air volume regulating valve 17-6, seventh air volume regulating valve 17-7, eighth air volume regulating valve 17-8, ninth air volume regulating valve 17-9, air duct 18, first heat pipe heat exchanger 19-1, second heat pipe heat exchanger 19-2. Figure 2 As shown, the first heat storage condenser 2-1 and the second heat storage condenser 2-2 are both coil-type heat exchangers with heat storage medium, and the heat storage medium can be an organic phase change heat storage material such as paraffin, or an inorganic hydrated salt phase change heat storage material such as zinc nitrate. Condenser 3 is an air-cooled heat exchanger such as fin tube, plate fin, etc., and evaporator 7 is an air-cooled heat exchanger such as fin tube, plate fin, etc. The first total heat exchanger 16-1 and the second total heat exchanger 16-2 are total heat exchangers with built-in fans. The first heat pipe heat exchanger 19-1 and the second heat pipe heat exchanger 19-2 are heat pipe type heat exchangers, which contain a plurality of heat pipes inside, and the heat pipes are normal temperature heat pipes. The evaporation sections of the first heat pipe heat exchanger 19-1 and the second heat pipe heat exchanger 19-2 are respectively placed on the outlet connecting air duct 18 of the first dehumidification box 15-1 and the second dehumidification box 15-2, and the condensation sections of the first heat pipe heat exchanger 19-1 and the second heat pipe heat exchanger 19-2 are placed in the middle branch of the three branches of the air duct 18 connected to the outlet of the drying box 14.

[0032] The first heat storage condenser 2-1 and the second heat storage condenser 2-2 of the system are respectively built into the first dehumidification box 15-1 and the second dehumidification box 15-2, and solid hygroscopic materials such as silica gel and calcium chloride are placed on the first heat storage condenser 2-1 and the second heat storage condenser 2-2 in the first dehumidification box 15-1 and the second dehumidification box 15-2.

[0033] In the heat pump subsystem, the outlet of the compressor 1 is connected to the inlet of the sixth solenoid valve 8, the inlet of the first solenoid valve 9-1 and the inlet of the second solenoid valve 9-2 respectively, the outlet of the sixth solenoid valve 8 is connected to the working medium inlet of the condenser 3, the outlet of the first solenoid valve 9-1 is connected to the inlet of the first heat storage condenser 2-1, the outlet of the first heat storage condenser 2-1 is connected to the inlet of the third solenoid valve 9-3, the outlet of the second solenoid valve 9-2 is connected to the inlet of the second heat storage condenser 2-2, the outlet of the second heat storage condenser 2-2 is connected to the inlet of the third solenoid valve 9-3, the outlet of the second solenoid valve 9-2 is connected to the inlet of the second heat storage condenser 2-2, the outlet of the second heat storage The inlet of the fourth solenoid valve 9-4 and the outlet of the fourth solenoid valve 9-4 are respectively connected to the outlet of the third solenoid valve 9-3, the working fluid inlet of the condenser 3, the outlet of the sixth solenoid valve 8 and the inlet of the seventh solenoid valve 20, the working fluid outlet of the condenser 3 is connected to the outlet of the seventh solenoid valve 20 and the inlet of the liquid reservoir 4, the outlet of the liquid reservoir 4 is connected to the inlet of the fifth solenoid valve 5, the outlet of the fifth solenoid valve 5 is connected to the inlet of the throttle valve 6, the outlet of the throttle valve 6 is connected to the inlet of the evaporator 7, and the outlet of the evaporator 7 is connected to the inlet of the compressor 1.

[0034] In the dry air subsystem, the fan 10 is placed in the air duct 18 and connected to the inlet of the drying box 14 through the air duct 18. The air duct 18 at the outlet of the drying box 14 is divided into three branches. The lower branch of the three branches is connected to the inlet of the first air volume regulating valve 17-1 through the air duct 18. The outlet of the first air volume regulating valve 17-1 is connected to the inlet of the first dehumidification box 15-1 and the outlet of the fourth air volume regulating valve 17-4 through the air duct 18. The outlet of the first dehumidification box 15-1 is connected to the inlet of the evaporation section of the first heat pipe heat exchanger 19-1. The outlet of the evaporation section of the first heat pipe heat exchanger 19-1 is respectively connected to the inlet of the sixth air volume regulating valve 17-6 and the inlet of the eighth air volume regulating valve 17-8, the fresh air passage inlet of the first total heat exchanger 16-1 is connected to the environment, the fresh air passage outlet of the first total heat exchanger 16-1 is connected to the inlet of the fourth air volume regulating valve 17-4, the outlet of the sixth air volume regulating valve 17-6 is connected to the exhaust passage inlet of the first total heat exchanger 16-1, and the exhaust passage outlet of the first total heat exchanger 16-1 leads to the outdoor environment. The upper branch of the three branches is connected to the inlet of the second air volume regulating valve 17-2 through the air duct 18, and the outlet of the second air volume regulating valve 17-2 is respectively connected to the inlet of the second dehumidification box 15-2 and the outlet of the fifth air volume regulating valve 17-5 through the air duct 18. The outlet of the second dehumidification box 15-2 is connected to the inlet of the evaporation section of the second heat pipe heat exchanger 19-2, and the outlet of the evaporation section of the second heat pipe heat exchanger 19-2 is respectively connected to the inlet of the seventh air volume regulating valve 17-7 and the inlet of the ninth air volume regulating valve 17-9. The inlet of the fresh air passage of the second total heat exchanger 16-2 is communicated with the environment, and the outlet of the fresh air passage of the second total heat exchanger 16-2 is connected to the outlet of the fifth air volume regulating valve 17 -5, the outlet of the seventh air volume regulating valve 17-7 is connected to the inlet of the exhaust passage of the second total heat exchanger 16-2, and the outlet of the exhaust passage of the second total heat exchanger 16-2 leads to the outdoor environment; the middle branch of the three branches is connected to the inlet of the third air volume regulating valve 17-3 through the air duct 18, the outlet of the third air volume regulating valve 17-3 is connected to the inlet of the condensing section of the second heat pipe heat exchanger 19-2, the outlet of the condensing section of the second heat pipe heat exchanger 19-2 is connected to the inlet of the condensing section of the first heat pipe heat exchanger 19-1, and the outlet of the condensing section of the first heat pipe heat exchanger 19-1 is respectively connected to the outlet of the eighth air volume regulating valve 17-8 and the outlet of the ninth air volume regulating valve 17-9. The outlets of the eighth air volume regulating valve 17-8 and the ninth air volume regulating valve 17-9 are connected to the gas inlet of the condenser 3 through the air duct 18, and the gas outlet of the condenser 3 is connected to the inlet of the drying box 14 through the air duct 18.

[0035] An operation method of a heat pump drying system with direct humidity regulation includes two modes: a drying operation without dehumidification mode and a drying operation with dehumidification mode.

[0036] In the dry operation without dehumidification mode, the sixth solenoid valve 8 of the heat pump subsystem is opened, and the first solenoid valve 9-1, the second solenoid valve 9-2 and the seventh solenoid valve 20 are closed. The refrigerant medium is compressed by the compressor 1 and becomes a high-temperature and high-pressure gas, and enters the condenser 3 through the sixth solenoid valve 8. The medium is heat-exchanged with the air in the condenser 3 and becomes a high-temperature and high-pressure liquid, and enters the liquid storage 4, and then enters the throttle valve 6 through the fifth solenoid valve 5. After throttling by the throttle valve 6, it becomes a low-temperature and low-pressure gas and flows into the evaporator 7. After absorbing heat in the evaporator 7, it is completely vaporized and then enters the compressor 1 to continue the next cycle.

[0037] In the dry operation dehumidification mode, the sixth solenoid valve 8 of the heat pump subsystem is closed, and at least one of the first solenoid valve 9-1 and the second solenoid valve 9-2 is opened. When the drying air temperature meets the drying set temperature of the material, the seventh solenoid valve 20 is opened, otherwise the seventh solenoid valve 20 is closed. When the first solenoid valve 9-1 is opened, the refrigerant medium is compressed by the compressor 1 and becomes a high-temperature and high-pressure gas, which enters the first heat storage condenser 2-1 through the first solenoid valve 9-1, releases the sensible heat of the compressor exhaust, and then enters the condenser 3 through the third solenoid valve 9-3. When the second solenoid valve 9-2 is opened, the high-temperature and high-pressure gas discharged from the compressor 1 enters the second heat storage condenser 2-2 through the second solenoid valve 9-2, releases the sensible heat of the compressor exhaust, and then enters the condenser 3 through the fourth solenoid valve 9-4. The compressor exhaust releases heat in the first heat storage condenser 2-1 and the second heat storage condenser 2-2 to first heat the heat storage phase change medium therein, and then transfers the heat to the solid hygroscopic material to evaporate the water therein. If the drying air temperature is lower than the set drying temperature of the material, the seventh solenoid valve 20 is closed, and the working fluid enters the condenser 3 and exchanges heat with the air to become a high-temperature and high-pressure liquid, and enters the liquid storage 4. Otherwise, the seventh solenoid valve 20 is opened, and the refrigerant directly enters the liquid storage 4. Then it enters the throttle valve 6 through the fifth solenoid valve 5, and after throttling by the throttle valve 6, it becomes a low-temperature and low-pressure gas and flows into the evaporator 7. After absorbing heat in the evaporator 7, it is completely vaporized and then enters the compressor 1 to complete the next cycle. When the heat pump is running in the non-dehumidification mode, the heat pump subsystem can also operate to store heat in the heat storage condenser 2-1 and the second heat storage condenser 2-2.

[0038] In the dry operation without dehumidification mode, the third air volume regulating valve 17-3 in the dry air subsystem is opened, and the other first air volume regulating valves 17-1, second air volume regulating valves 17-2, fourth air volume regulating valves 17-4, fifth air volume regulating valves 17-5, sixth air volume regulating valves 17-6, seventh air volume regulating valves 17-7, eighth air volume regulating valves 17-8, and ninth air volume regulating valves 17-9 are all closed. Driven by the fan 10, the dry air is heated by the condenser 3, enters the drying box 14 to the drying temperature, takes away the moisture of the material, and enters the condenser 3 again after passing through the third air volume regulating valve 17-3, and repeats the above cycle after heating.

[0039] In the dry operation dehumidification mode, at least one of the upper branch or the lower branch of the dry air subsystem is opened, and the third air volume regulating valve 17-3 is closed or partially opened. When the third air volume regulating valve 17-3 is partially opened, air flows in the middle branch, and the air of the middle branch and the two branches of the upper branch or the lower branch are mixed to achieve relative humidity adjustment. In this way, the opening of the air volume regulating valve can be changed, so that the flow of each branch reaches the relative humidity setting value after mixing.

[0040] When the lower branch is opened, the dry air is dehumidified through the lower branch, and the upper branch performs heating and regeneration of the dehumidifying material. At this time, the first air volume regulating valve 17-1, the fifth air volume regulating valve 17-5, the seventh air volume regulating valve 17-7 and the eighth air volume regulating valve 17-8 are all opened, and the second air volume regulating valve 17-2, the fourth air volume regulating valve 17-4, the sixth air volume regulating valve 17-6, and the ninth air volume regulating valve 17-9 are all closed. In the heat pump subsystem, the sixth solenoid valve 8 and the seventh solenoid valve 20 are closed, and the second solenoid valve 9-2 is opened. When the second solenoid valve 9-2 is opened, the second heat storage condenser 2-2 and the heat storage medium therein heat the solid hygroscopic material, evaporate the water therein, and complete the regeneration of the hygroscopic material. Driven by the fan 10, the dry air is heated by the condenser 3 and enters the drying box 14 to the drying temperature, taking away the moisture of the material. All or part of the air enters the first dehumidification box 15-1 through the first air volume regulating valve 17-1, and the dehumidification material in the first dehumidification box 15-1 removes the moisture in the air. After the air absorbs moisture and the temperature rises, it flows out of the first dehumidification box 15-1 and enters the evaporation section of the first heat pipe heat exchanger 19-1, transferring the heat to the working medium in the evaporation section. After the working medium is vaporized, it rises and enters the condensation section of the first heat pipe heat exchanger 19-1, releasing heat to the air in the middle branch, realizing heat recovery. The dry air flows out of the evaporation section of the first heat pipe heat exchanger 19-1 and flows out through the eighth air volume regulating valve 17-8. When only part of the air passes through the first air volume regulating valve 17-1, the other part of the air flows out after passing through the third air volume regulating valve 17-3 (partially opened), and then enters the condenser 3 after merging with the air flowing out of the eighth air volume regulating valve 17-8, and repeats the above cycle after heating. The outdoor air enters through the fresh air passage of the second total heat exchanger 16-2, and then enters the second dehumidifier box 15-2 through the fifth air volume regulating valve 17-5 to take away the water evaporated by the hygroscopic material, enters the evaporation section of the second heat pipe heat exchanger 19-2 to release heat, and then flows into the exhaust passage inlet of the second total heat exchanger 16-2 through the seventh air volume regulating valve 17-7, and is discharged to the outdoor environment after releasing heat, completing the regeneration of the hygroscopic material.

[0041] When the upper branch is opened, the dry air is dehumidified through the upper branch, and the lower branch performs heating and regeneration of the dehumidifying material. At this time, the second air volume regulating valve 17-2, the fourth air volume regulating valve 17-4, the sixth air volume regulating valve 17-6 and the ninth air volume regulating valve 17-9 are all opened, and the first air volume regulating valve 17-1, the fifth air volume regulating valve 17-5, the seventh air volume regulating valve 17-7, and the eighth air volume regulating valve 17-8 are all closed. The sixth solenoid valve 8 in the heat pump subsystem is closed and the first solenoid valve 9-1 is opened. When the first solenoid valve 9-1 is opened, the first heat storage condenser 2-1 and the heat storage medium therein heat the solid hygroscopic material, evaporate the water therein, and complete the regeneration of the hygroscopic material. Driven by the fan 10, the dry air is heated by the condenser 3 and enters the drying box 14 to the drying temperature, taking away the moisture of the material. All or part of the air enters the second dehumidification box 15-2 through the second air volume regulating valve 17-2, and the dehumidification material in the second dehumidification box 15-2 removes the moisture in the air. After the air absorbs moisture and the temperature rises, it flows out of the second dehumidification box 15-2 and enters the evaporation section of the second heat pipe heat exchanger 19-2, transferring the heat to the working medium in the evaporation section. After the working medium is vaporized, it rises and enters the condensation section of the second heat pipe heat exchanger 19-2, releasing heat to the air in the middle branch, realizing heat recovery. After the dry air flows out of the evaporation section of the second heat pipe heat exchanger 19-2, it flows out through the ninth air volume regulating valve 17-9. When only part of the air passes through the second air volume regulating valve 17-2, the other part of the air flows out after passing through the third air volume regulating valve 17-3 (partially opened), and then enters the condenser 3 after merging with the air flowing out of the ninth air volume regulating valve 17-9, and repeats the above cycle after heating. The outdoor air enters through the fresh air passage of the first total heat exchanger 16-1, enters the first dehumidifier box 15-1 through the fourth air volume regulating valve 17-4, takes away the water evaporated from the hygroscopic material, and flows into the exhaust passage inlet of the first total heat exchanger 16-1 through the sixth air volume regulating valve 17-6, and is discharged to the outdoor environment after releasing heat, completing the regeneration of the hygroscopic material.

[0042] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0043] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features.

[0044] Parts not elaborated in detail in this specification belong to the prior art. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A heat pump drying system with direct humidity regulation, Features It includes a heat pump subsystem and a dry air subsystem; The heat pump subsystem includes a compressor, the outlet of the compressor is respectively connected to the inlet of the sixth solenoid valve, the inlet of the first solenoid valve and the inlet of the second solenoid valve, the outlet of the sixth solenoid valve is connected to the working fluid inlet of the condenser, the outlet of the first solenoid valve is connected to the inlet of the first heat storage condenser, the outlet of the first heat storage condenser is connected to the inlet of the third solenoid valve, the outlet of the second solenoid valve is connected to the inlet of the second heat storage condenser, the outlet of the second heat storage condenser is connected to the inlet of the fourth solenoid valve, the outlet of the fourth solenoid valve is respectively connected to the outlet of the third solenoid valve, the working fluid inlet of the condenser, the outlet of the sixth solenoid valve and the inlet of the seventh solenoid valve, the working fluid outlet of the condenser is connected to the outlet of the seventh solenoid valve and the inlet of the liquid reservoir, the outlet of the liquid reservoir is connected to the inlet of the fifth solenoid valve, the outlet of the fifth solenoid valve is connected to the inlet of the throttle valve, the outlet of the throttle valve is connected to the inlet of the evaporator, and the outlet of the evaporator is connected to the inlet of the compressor; The dry air subsystem includes a fan, which is placed in an air duct and connected to the inlet of a drying box through the air duct. The air duct at the outlet of the drying box is divided into three branches. The lower branch of the three branches is connected to the inlet of a first air volume regulating valve through the air duct. The outlet of the first air volume regulating valve is connected to the inlet of a first dehumidification box and the outlet of a fourth air volume regulating valve through the air duct. The outlet of the first dehumidification box is connected to the inlet of the evaporation section of the first heat pipe heat exchanger. The outlet of the evaporation section of the first heat pipe heat exchanger is respectively connected to the inlet of a sixth air volume regulating valve and the inlet of an eighth air volume regulating valve. The inlet of a fresh air passage of the first total heat exchanger is connected to the environment. The outlet of the fresh air passage of the first total heat exchanger is connected to the inlet of the fourth air volume regulating valve. The outlet of the sixth air volume regulating valve is connected to the exhaust air of the first total heat exchanger. The passage inlet and the exhaust passage outlet of the first total heat exchanger lead to the outdoor environment; the upper branch of the three branches is connected to the inlet of the second air volume regulating valve through the air duct, the outlet of the second air volume regulating valve is respectively connected to the inlet of the second dehumidification box and the outlet of the fifth air volume regulating valve through the air duct, the outlet of the second dehumidification box is connected to the inlet of the evaporation section of the second heat pipe heat exchanger, the outlet of the evaporation section of the second heat pipe heat exchanger is respectively connected to the inlet of the seventh air volume regulating valve and the inlet of the ninth air volume regulating valve, the fresh air passage inlet of the second total heat exchanger is connected to the environment, the fresh air passage outlet of the second total heat exchanger is connected to the inlet of the fifth air volume regulating valve, the outlet of the seventh air volume regulating valve is connected to the exhaust passage inlet of the second total heat exchanger, and the exhaust passage outlet of the second total heat exchanger leads to the outdoor environment; The middle branch of the three branches is connected to the inlet of the third air volume regulating valve through the air duct, the outlet of the third air volume regulating valve is connected to the inlet of the condensing section of the second heat pipe heat exchanger, the outlet of the condensing section of the second heat pipe heat exchanger is connected to the inlet of the condensing section of the first heat pipe heat exchanger, and the outlet of the condensing section of the first heat pipe heat exchanger is connected to the outlet of the eighth air volume regulating valve and the outlet of the ninth air volume regulating valve respectively; the outlet of the eighth air volume regulating valve and the outlet of the ninth air volume regulating valve are connected to the gas inlet of the condenser through the air duct, and the gas outlet of the condenser is connected to the inlet of the drying box through the air duct; The first heat storage condenser and the second heat storage condenser are respectively built in the first dehumidification box and the second dehumidification box, and solid moisture absorbing materials are placed on the first heat storage condenser and the second heat storage condenser.

2. A heat pump drying system with direct humidity control according to claim 1, Features The first heat storage condenser and the second heat storage condenser are both coil-type heat exchangers with heat storage medium.

3. A heat pump drying system with direct humidity control according to claim 2, Features The heat storage medium is an organic phase change heat storage material or an inorganic hydrated salt phase change heat storage material.

4. A heat pump drying system with direct humidity control according to claim 3, Features The heat storage medium is paraffin or zinc nitrate.

5. A heat pump drying system with direct humidity control according to claim 1, Features The condenser is a fin tube or plate fin air-cooled heat exchanger, and the evaporator is a fin tube or plate fin air-cooled heat exchanger.

6. A heat pump drying system with direct humidity control according to claim 1, Features The first total heat exchanger and the second total heat exchanger are total heat exchangers with built-in fans.

7. A heat pump drying system with direct humidity control according to claim 1, Features The first heat pipe heat exchanger and the second heat pipe heat exchanger are heat pipe type heat exchangers, which contain a plurality of heat pipes inside, and the heat pipes are normal temperature heat pipes.

8. A heat pump drying system with direct humidity control according to claim 1, Features The solid hygroscopic material is one of silica gel and calcium chloride.

9. The operating method of a heat pump drying system with direct humidity control according to claim 1, Features Including a dry operation without dehumidification mode, the sixth solenoid valve in the heat pump subsystem is opened, and the first solenoid valve, the second solenoid valve and the seventh solenoid valve are closed; After being compressed by the compressor, the refrigerant becomes a high-temperature and high-pressure gas, enters the condenser through the sixth solenoid valve, and becomes a high-temperature and high-pressure liquid after heat exchange with the air in the condenser, enters the liquid storage tank, and then enters the throttle valve through the fifth solenoid valve. After throttling by the throttle valve, it becomes a low-temperature and low-pressure gas and flows into the evaporator. After absorbing heat in the evaporator, it is completely vaporized and then enters the compressor to continue the next cycle; the third air volume regulating valve in the dry air subsystem is opened, and the remaining first air volume regulating valve, second air volume regulating valve, fourth air volume regulating valve, fifth air volume regulating valve, sixth air volume regulating valve, seventh air volume regulating valve, eighth air volume regulating valve, and ninth air volume regulating valve are all closed; driven by the fan, the dry air is heated by the condenser and then enters the drying box for drying, taking away the moisture of the material, and then enters the condenser after passing through the third air volume regulating valve, and repeats the above cycle after heating.

10. The operating method of the heat pump drying system with direct humidity control according to claim 1, Features Including a dry operation dehumidification mode, the sixth solenoid valve in the heat pump subsystem is closed, and at least one of the first solenoid valve and the second solenoid valve is opened; when the dry air temperature meets the drying set temperature of the material, the seventh solenoid valve is opened, otherwise the seventh solenoid valve is closed; when the first solenoid valve is opened, the refrigerant medium is compressed by the compressor and becomes a high-temperature and high-pressure gas, enters the first heat storage condenser through the first solenoid valve, releases the sensible heat of the compressor exhaust, and then enters the condenser through the third solenoid valve; when the second solenoid valve is opened, the high-temperature and high-pressure gas discharged by the compressor enters the second heat storage condenser through the second solenoid valve, releases the sensible heat of the compressor exhaust, and then enters the condenser through the fourth solenoid valve. Enter the condenser; the compressor exhaust releases heat in the first heat storage condenser and the second heat storage condenser to heat the heat storage phase change medium first, and then transfers the heat to the solid hygroscopic material to evaporate the water therein; if the dry air temperature is lower than the drying set temperature of the material, the seventh solenoid valve is closed, and the working fluid enters the condenser and exchanges heat with the air to become a high-temperature and high-pressure liquid and enter the liquid storage tank, otherwise the seventh solenoid valve is opened, and the refrigerant directly enters the liquid storage tank; then it enters the throttle valve through the fifth solenoid valve, and after throttling by the throttle valve, it becomes a low-temperature and low-pressure gas and flows into the evaporator, absorbs heat in the evaporator and is completely vaporized, and then enters the compressor to continue to complete the next cycle; At least one of the upper branch or the lower branch in the dry air subsystem is opened, and the third air volume regulating valve is closed or partially opened; When the lower branch is opened, dry air is dehumidified through the lower branch, and the upper branch conducts the heating regeneration operation of the dehumidification material; at this time, the first air volume regulating valve, the fifth air volume regulating valve, the seventh air volume regulating valve, and the eighth air volume regulating valve are all opened, and the second air volume regulating valve, the fourth air volume regulating valve, the sixth air volume regulating valve, and the ninth air volume regulating valve are all closed; in the heat pump subsystem, the sixth solenoid valve and the seventh solenoid valve are closed, and the second solenoid valve is opened; when the second solenoid valve is opened, the second regenerative condenser and the regenerative medium therein heat the solid moisture absorbent material, and the moisture therein is evaporated to complete the regeneration of the moisture absorbent material; driven by the fan, the dry air is heated by the condenser and then enters the drying box for drying, taking away the moisture of the material. All or part of the air enters the first dehumidification box through the first air volume regulating valve, and the moisture in the air is removed by the dehumidification material in the first dehumidification box. After the air absorbs moisture and the temperature rises, it flows out of the first dehumidification box and enters the evaporation section of the first heat pipe heat exchanger, transferring heat to the working medium in the evaporation section. After the working medium vaporizes, it rises and enters the condensation section of the first heat pipe heat exchanger, releasing heat to the air in the middle branch to achieve heat recovery; the dry air flows out of the evaporation section of the first heat pipe heat exchanger and then flows out through the eighth air volume regulating valve; when only part of the air passes through the first air volume regulating valve, the other part of the air flows out through the third air volume regulating valve, converges with the air flowing out through the eighth air volume regulating valve, and then enters the condenser. After heating, the above cycle is repeated; outdoor air enters through the fresh air passage of the second total heat exchanger, and then enters the second dehumidification box through the fifth air volume regulating valve to take away the moisture evaporated from the moisture absorbent material. After releasing heat in the evaporation section of the second heat pipe heat exchanger, it flows into the exhaust passage inlet of the second total heat exchanger through the seventh air volume regulating valve, and is discharged to the outdoor environment after releasing heat to complete the regeneration of the moisture absorbent material; When the upper branch is opened, the dry air is dehumidified through the upper branch, and the lower branch performs dehumidification material heating and regeneration operation; at this time, the second air volume regulating valve, the fourth air volume regulating valve, the sixth air volume regulating valve and the ninth air volume regulating valve are all opened, and the first air volume regulating valve, the fifth air volume regulating valve, the seventh air volume regulating valve and the eighth air volume regulating valve are all closed; the sixth solenoid valve in the heat pump subsystem is closed and the first solenoid valve is opened; when the first solenoid valve is opened, the first heat storage condenser and the heat storage medium therein heat the solid hygroscopic material to evaporate the moisture therein and complete the regeneration of the hygroscopic material; driven by the fan, the dry air is heated by the condenser and then enters the drying box for drying, taking away the moisture of the material, and all or part of the air enters the second dehumidification box through the second air volume regulating valve, and the dehumidification material in the second dehumidification box removes the moisture in the air, and the air absorbs moisture After the temperature rises and flows out of the second dehumidification box, it enters the evaporation section of the second heat pipe heat exchanger, transfers the heat to the working medium in the evaporation section, and the working medium rises and enters the condensation section of the second heat pipe heat exchanger after vaporization, releasing heat to the air in the middle branch, thereby realizing heat recovery; after the dry air flows out of the evaporation section of the second heat pipe heat exchanger, it flows out through the ninth air volume regulating valve; when only part of the air passes through the second air volume regulating valve, the other part of the air flows out after the third air volume regulating valve, merges with the air flowing out of the ninth air volume regulating valve, and then enters the condenser, repeating the above cycle after heating; the outdoor air enters through the fresh air passage of the first total heat exchanger, enters the first dehumidification box through the fourth air volume regulating valve, takes away the moisture evaporated from the hygroscopic material, flows into the inlet of the exhaust passage of the first total heat exchanger through the sixth air volume regulating valve, is discharged to the outdoor environment after releasing heat, and completes the regeneration of the hygroscopic material.

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