A multi-operating mode fruit and vegetable drying system and method

Abstract

The application discloses a multi-operation-mode fruit and vegetable drying system and method, which dries fruit and vegetables by adjusting the temperature and humidity of air sent into a drying chamber, and comprises a solid dehumidification system, a refrigeration dehumidification system and an adjusting system, three operation modes of a single solid dehumidification mode, a single refrigeration dehumidification mode and a combined mode of solid dehumidification and refrigeration dehumidification are realized through adjusting control of the adjusting system; the sensible heat recovery plate heat exchanger is used for pre-treating fresh air, regeneration of adsorbents in an air regeneration channel of the solid dehumidification device is completed, and heat waste is reduced; the temperature and humidity of fruit and vegetables in the drying chamber are monitored in real time, and the start and stop of a wind valve are controlled, and thus a suitable drying operation mode is selected, so that the system energy consumption is reduced, the fruit and vegetable drying efficiency is improved, and the storage fruit and vegetable quality is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of drying, and particularly relates to a multi-operation-mode fruit and vegetable drying system and method. BACKGROUND

[0002] The short shelf life of fruits and vegetables brings many disadvantages to their storage and sales. With the progress of industrial technology, the storage time can be prolonged, the loss can be reduced, and the nutrients and original taste can be preserved by various drying methods. The existing drying methods include heat pump drying, hot air drying, infrared radiation drying, microwave combined drying, vacuum freeze drying, etc., but there are generally problems such as high drying energy consumption, uneven quality of fruits and vegetables after drying, etc.

[0003] The solid dehumidification device can work continuously, has the advantages of low dew point, deep dehumidification and independent control of temperature and humidity, but the dehumidification energy consumption is large because the adsorbent in the regeneration channel needs to be regenerated and heated during operation; at the same time, the high-temperature and high-humidity regeneration exhaust directly discharged into the environment will cause energy waste and environmental heat pollution. The essence of heat pump drying is hot air convection drying, and in recent years, heat pump drying technology has been widely applied. Heat pump drying follows the Carnot cycle, has the characteristics of energy saving and environmental friendliness, and the temperature of the hot air after dehumidification can be as high as 60℃, and the effect of dried agricultural products is good, but the dew point temperature after dehumidification is higher than 5℃, and the dehumidification capacity is not as good as the adsorption dehumidification method, and the drying rate is low at low temperature.

[0004] In summary, the fruit and vegetable drying system also has the following deficiencies: (1) the regeneration temperature of the adsorbent in the air regeneration channel of the solid dehumidification device is high, resulting in high drying energy consumption; (2) the moisture ratio of fruits and vegetables does not change uniformly over time, and generally changes rapidly in the first few hours, and as the drying process proceeds, the drying rate becomes slower and slower, and if the supply air temperature in the drying chamber remains constant at this time, energy will be wasted; (3) different fruits and vegetables require different supply air temperatures, and the system should meet the different supply air requirements to the maximum extent. In view of the above problems, a multi-operation-mode fruit and vegetable drying system and method are proposed. SUMMARY

[0005] The present application aims to overcome the deficiencies in the prior art, and provides a multi-operation-mode fruit and vegetable drying system. The present application combines solid dehumidification technology and freeze dehumidification technology, and uses a heat pump to drive, realizing three operation modes of single solid dehumidification mode, single freeze dehumidification mode and solid dehumidification and freeze dehumidification combined mode; the new air is pretreated by the sensible heat recovery plate heat exchanger to regenerate the adsorbent in the air regeneration channel of the solid dehumidification device, reducing heat waste; the temperature and humidity of fruits and vegetables in the drying chamber are monitored in real time, the drying operation mode is selected by starting and stopping the control of the air valve, so as to reduce the system energy consumption, improve the fruit and vegetable drying efficiency, and improve the storage fruit and vegetable quality.

[0006] To solve the above problems, the present application provides a multi-operation mode fruit and vegetable drying system, which dries the fruit and vegetable in the drying chamber by adjusting the temperature and humidity of the air sent into the drying chamber, characterized in that it comprises:

[0007] The solid dehumidification system comprises a solid dehumidification device, a sensible heat recovery plate heat exchanger, a regeneration condenser and an electric heating auxiliary device, the solid dehumidification device comprises a solid dehumidification device air treatment channel and a solid dehumidification device air regeneration channel, the air outlet of the solid dehumidification device air treatment channel is connected with the air inlet of the drying chamber for sending the air dehumidified by the solid dehumidification device air treatment channel into the drying chamber, the hot fluid air inlet of the sensible heat recovery plate heat exchanger is connected with the air outlet of the drying chamber, the cold fluid air inlet of the sensible heat recovery plate heat exchanger is connected with the outside air, the cold fluid air outlet of the sensible heat recovery plate heat exchanger is connected with the air inlet of the regeneration condenser, the air outlet of the regeneration condenser is connected with the air inlet of the electric heating auxiliary device, and the air outlet of the electric heating auxiliary device is connected with the air inlet of the solid dehumidification device air regeneration channel.

[0008] The refrigeration dehumidification system comprises a variable frequency compressor, a drying condenser and a main evaporator, the working medium outlet of the variable frequency compressor is connected with the working medium inlet of the drying condenser, the working medium outlet of the drying condenser is connected with the working medium inlet of the regeneration condenser, the working medium outlet of the regeneration condenser is connected with the first port of the expansion valve, the second port of the expansion valve is connected with the working medium inlet of the main evaporator, the working medium outlet of the main evaporator is connected with the working medium inlet of the variable frequency compressor, the air inlet of the main evaporator is connected with the outside air, the air outlet of the main evaporator is connected with the air inlet of the drying condenser, and the air outlet of the drying condenser is connected with the air inlet of the drying chamber.

[0009] The adjustment system comprises a second temperature and humidity detection device, a first air valve, a second air valve, a third temperature and humidity detection device and a fourth temperature and humidity detection device, the second port of the first air valve is connected with the air inlet of the main evaporator, the first port of the first air valve is connected with the outside air, the second port of the second air valve is connected with the air inlet of the solid dehumidification device air treatment channel, the first port of the second air valve is connected with the outside air, the second temperature and humidity detection device is arranged on the end where the first air valve and the second air valve are connected with the outside air, for detecting the temperature and humidity of the air entering the first air valve and the second air valve, the third temperature and humidity detection device is arranged at the air inlet of the drying chamber, for detecting the temperature and humidity of the air entering the drying chamber, and the fourth temperature and humidity detection device is arranged at the air outlet of the drying chamber, for detecting the temperature and humidity of the air coming out of the drying chamber.

[0010] The multi-operation mode fruit and vegetable drying system, characterized in that: the multi-operation mode fruit and vegetable drying system further comprises a three-way valve and a return air adjusting valve, a first port of the three-way valve is in communication with a hot fluid air outlet of the sensible heat recovery plate heat exchanger, a second port of the three-way valve is in communication with a second port of the return air adjusting valve, a third port of the three-way valve is in communication with external air, and a first port of the return air adjusting valve is in communication with a first port of the second air valve and a first port of the first air valve respectively.

[0011] The multi-operation mode fruit and vegetable drying system, characterized in that: the multi-operation mode fruit and vegetable drying system further comprises a second fresh air fan and a fifth temperature and humidity detection device, an air outlet of the second fresh air fan is in communication with a cold fluid air inlet of the sensible heat recovery plate heat exchanger, for sending external air into the sensible heat recovery plate heat exchanger, and the fifth temperature and humidity detection device is arranged at an air inlet of the second fresh air fan, for detecting the temperature and humidity of the air entering the second fresh air fan.

[0012] The multi-operation mode fruit and vegetable drying system, characterized in that: the multi-operation mode fruit and vegetable drying system further comprises a regeneration exhaust air fan, an air inlet of the regeneration exhaust air fan is in communication with an air outlet of the solid dehumidification device air regeneration channel, for discharging the air passing through the solid dehumidification device air regeneration channel.

[0013] The multi-operation mode fruit and vegetable drying system, characterized in that: the multi-operation mode fruit and vegetable drying system further comprises a first electromagnetic valve, a second electromagnetic valve and an auxiliary evaporator, a first port of the first electromagnetic valve is in communication with a working medium outlet of the main evaporator, a second port of the first electromagnetic valve is in communication with a working medium inlet of the variable frequency compressor, a first port of the second electromagnetic valve is in communication with the working medium outlet of the main evaporator, a second port of the second electromagnetic valve is in communication with a working medium inlet of the auxiliary evaporator, and a working medium outlet of the auxiliary evaporator is in communication with the working medium inlet of the variable frequency compressor.

[0014] The multi-operation mode fruit and vegetable drying system, characterized in that: the multi-operation mode fruit and vegetable drying system further comprises a third air valve and a fourth air valve, a first port of the third air valve is in communication with an air outlet of the main evaporator, a second port of the third air valve is in communication with an air inlet of the drying condenser, a first port of the fourth air valve is in communication with the air outlet of the main evaporator, and a second port of the fourth air valve is in communication with an air inlet of the solid dehumidification device air treatment channel.

[0015] The multi-operation mode fruit and vegetable drying system has the characteristics that the multi-operation mode fruit and vegetable drying system further comprises a first fresh air fan, a fresh air regulating valve and a first temperature and humidity detection device, the second port of the fresh air regulating valve is in communication with the first port of the first air valve, the first port of the second air valve and the first port of the return air regulating valve respectively, the air outlet of the first fresh air fan is in communication with the first port of the fresh air regulating valve, and the first temperature and humidity detection device is arranged at the air inlet of the first fresh air fan and used for detecting the temperature and humidity of the air entering the first fresh air fan.

[0016] The application further discloses a multi-operation mode fruit and vegetable drying method.

[0017] The temperature and humidity of the air entering the drying chamber are detected by using the third temperature and humidity detection device in the multi-operation mode fruit and vegetable drying system.

[0018] The operation mode is selected according to the detection result of the third temperature and humidity detection device.

[0019] When the temperature t detected by the third temperature and humidity detection device is less than 50 DEG C, a single solid dehumidification mode is applied, that is, the first air valve, the third air valve and the fourth air valve are closed, the second air valve is opened, the air is isenthalpically dehumidified through the air treatment channel of the solid dehumidification device, and the low-humidity air is sent into the drying chamber to dry the fruits and vegetables. s

[0020] When the temperature t detected by the third temperature and humidity detection device is greater than 50 DEG C, the dew point temperature t is greater than 10 DEG C, and a single refrigeration dehumidification mode is applied, that is, the second air valve and the fourth air valve are closed, the first air valve and the third air valve are opened, the air is cooled and dehumidified through the main evaporator, then is heated through the drying condenser, and finally is sent into the drying chamber to dry the fruits and vegetables. s sl

[0021] When the temperature t detected by the third temperature and humidity detection device is greater than 50 DEG C, the dew point temperature t is less than 10 DEG C, and a solid dehumidification and refrigeration dehumidification combined mode is applied, that is, the second air valve and the third air valve are closed, the first air valve and the fourth air valve are opened, the air is cooled and dehumidified through the main evaporator first, then is isenthalpically dehumidified through the air treatment channel of the solid dehumidification device, and finally is heated through the drying condenser, and then is sent into the drying chamber to dry the fruits and vegetables. s sl

[0022] In the single solid dehumidification mode, the single refrigeration dehumidification mode and the solid dehumidification and refrigeration dehumidification combined mode, the first temperature and humidity detection device and the fourth temperature and humidity detection device are used to detect the temperature and humidity of the air passing through the air treatment channel.

[0023] ​​​​​When the humidity detected by the first temperature and humidity detection device is greater than the humidity detected by the fourth temperature and humidity detection device, a full return air system is applied, that is, the fresh air regulating valve and the three-way valve are closed, and the return air regulating valve is opened.

[0024] When the humidity detected by the first temperature and humidity detection device is less than the humidity detected by the fourth temperature and humidity detection device, a full fresh air system is applied, that is, the return air regulating valve is closed, and the fresh air regulating valve and the three-way valve are opened.

[0025] Compared with the prior art, the present application has the following advantages:

[0026] 1. The present application combines solid dehumidification technology and refrigeration dehumidification technology, and utilizes a heat pump to drive, to realize three operation modes of a separate solid dehumidification mode, a separate refrigeration dehumidification mode and a combined solid dehumidification and refrigeration dehumidification mode, to monitor the temperature and humidity of fruits and vegetables in a drying chamber in real time, to select a suitable drying operation mode by controlling the start and stop of an air valve, so as to reduce system energy consumption, improve fruit and vegetable drying efficiency and improve the quality of stored fruits and vegetables.

[0027] 2. The present application pre-processes fresh air through a sensible heat recovery plate heat exchanger, regenerates the adsorbent in the air regeneration channel of the solid dehumidification device, and reduces heat waste.

[0028] 3. The present application selects suitable treated air in the air treatment process by monitoring the outlet temperature and humidity of the drying chamber, avoids introducing high-humidity air into the system, can quickly discharge high-humidity gas in the system, improves the drying efficiency, balances the indoor air pressure and speeds up the drying of fruits and vegetables.

[0029] 4. The present application utilizes a heat pump to drive, utilizes a regeneration condenser to heat regeneration air, and can reduce the energy consumption of the solid dehumidification device air regeneration channel for adsorbent regeneration.

[0030] The application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 A schematic diagram of various components of the drying system and the connection relationship thereof in the embodiment of the present application is shown.

[0032] Figure 2 A separate solid dehumidification mode schematic diagram in the embodiment of the present application is shown.

[0033] Figure 3 A separate refrigeration dehumidification mode schematic diagram in the embodiment of the present application is shown.

[0034] Figure 4 A combined solid dehumidification and refrigeration dehumidification mode schematic diagram in the embodiment of the present application is shown.

[0035] Explanation of reference signs:

[0036] 1—First fresh air fan; 2—Fresh air regulating valve; 3—Main evaporator;

[0037] 41—Air handling passage for solid dehumidifier; 42—Air regeneration passage for solid dehumidifier;

[0038] 5—Condenser for drying; 6—Drying chamber; 7—Sensible heat recovery plate heat exchanger;

[0039] 8—Second fresh air fan; 9—Regeneration condenser; 10—Electric heating auxiliary unit;

[0040] 11—Regenerative exhaust fan; 12—Variable frequency compressor; 13—Expansion valve;

[0041] 14—First solenoid valve; 15—Second solenoid valve; 16—Auxiliary evaporator;

[0042] 17—Return air regulating valve; 18—Three-way valve; 19—First air valve;

[0043] 20—Second air valve; 21—Third air valve; 22—Fourth air valve;

[0044] 23—First temperature and humidity detection device; 24—Second temperature and humidity detection device;

[0045] 25—Third temperature and humidity detection device; 26—Fourth temperature and humidity detection device;

[0046] 27—Fifth temperature and humidity detection device. Detailed Implementation

[0047] Embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the invention. It should be understood that the accompanying drawings and embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the invention.

[0048] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0049] like Figure 1 As shown, it illustrates a schematic diagram of the various components of the drying system and their connection relationships in an embodiment of this disclosure.

[0050] exist Figure 1The air passing through the first and fifth temperature and humidity detection devices 23 and 27 is marked as fresh air F, the air passing through the second temperature and humidity detection device 24 is marked as treated air P, the air passing through the third temperature and humidity detection device 25 is marked as supply air S, and the air passing through the fourth temperature and humidity detection device 26 is marked as indoor air R.

[0051] The application discloses a multi-operation-mode fruit and vegetable drying system, which dries fruits and vegetables in a drying chamber 6 by adjusting the temperature and humidity of air sent into the drying chamber 6, and comprises a solid dehumidification system, a refrigeration dehumidification system and an adjusting system.

[0052] The solid dehumidification system comprises a solid dehumidification device, a sensible heat recovery plate heat exchanger 7, a regeneration condenser 9 and an electric heating auxiliary device 10, the solid dehumidification device comprises a solid dehumidification device air treatment channel 41 and a solid dehumidification device air regeneration channel 42, the air outlet of the solid dehumidification device air treatment channel 41 is connected with the air inlet of the drying chamber 6, and is used for sending air dehumidified through the solid dehumidification device air treatment channel into the drying chamber 6, the hot fluid air inlet of the sensible heat recovery plate heat exchanger 7 is connected with the air outlet of the drying chamber 6, the cold fluid air inlet of the sensible heat recovery plate heat exchanger 7 is connected with external air, the cold fluid air outlet of the sensible heat recovery plate heat exchanger 7 is connected with the air inlet of the regeneration condenser 9, the air outlet of the regeneration condenser 9 is connected with the air inlet of the electric heating auxiliary device 10, and the air outlet of the electric heating auxiliary device 10 is connected with the air inlet of the solid dehumidification device air regeneration channel 42.

[0053] The refrigeration dehumidification system comprises a variable frequency compressor 12, a drying condenser 5 and a main evaporator 3, the working medium outlet of the variable frequency compressor 12 is connected with the working medium inlet of the drying condenser 5, the working medium outlet of the drying condenser 5 is connected with the working medium inlet of the regeneration condenser 9, the working medium outlet of the regeneration condenser 9 is connected with the first port of an expansion valve 13, the second port of the expansion valve 13 is connected with the working medium inlet of the main evaporator 3, the working medium outlet of the main evaporator 3 is connected with the working medium inlet of the variable frequency compressor 12, the air inlet of the main evaporator 3 is connected with external air, the air outlet of the main evaporator 3 is connected with the air inlet of the drying condenser 5, and the air outlet of the drying condenser 5 is connected with the air inlet of the drying chamber 6.

[0054] The adjusting system comprises a second temperature and humidity detection device 24, a first air valve 19, a second air valve 20, a third temperature and humidity detection device 25, a fourth temperature and humidity detection device 26 and a control device, the second port of the first air valve 19 is communicated with the air inlet of the main evaporator 3, the first port of the first air valve 19 is communicated with the outside air, the second port of the second air valve 20 is communicated with the air inlet of the solid dehumidification device air treatment channel 41, the first port of the second air valve 20 is communicated with the outside air, the second temperature and humidity detection device 24 is arranged on the end, where the first air valve 19 and the second air valve 20 are communicated with the outside air, for detecting the temperature and humidity of the air entering the first air valve 19 and the second air valve 20, the third temperature and humidity detection device 25 is arranged at the air inlet of the drying chamber 6, for detecting the temperature and humidity of the air entering the drying chamber 6, the fourth temperature and humidity detection device 26 is arranged at the air outlet of the drying chamber 6, for detecting the temperature and humidity of the air coming out of the drying chamber 6, the control device is connected with the second temperature and humidity detection device 24, the third temperature and humidity detection device 25, the fourth temperature and humidity detection device 26, the first air valve 19 and the second air valve 20 respectively, for receiving the temperature, humidity and other data detected by the second temperature and humidity detection device 24, the third temperature and humidity detection device 25 and the fourth temperature and humidity detection device 26, and controlling the first air valve 19 and the second air valve 20 to act to realize the single solid dehumidification mode, the single refrigeration dehumidification mode or the combined mode of solid dehumidification and refrigeration dehumidification. The control device can be a programmable controller or a single-chip microcomputer.

[0055] The application combines the solid dehumidification technology and the refrigeration dehumidification technology, utilizes the heat pump driving, realizes the single solid dehumidification mode, the single refrigeration dehumidification mode and the combined mode of solid dehumidification and refrigeration dehumidification, pre-processes the fresh air through the sensible heat recovery plate heat exchanger 7, completes the regeneration of the adsorbent of the solid dehumidification device air regeneration channel, reduces the heat waste, monitors the temperature and humidity of the fruits and vegetables in the drying chamber in real time, selects the appropriate drying operation mode through the start and stop of the air valve, thereby reducing the system energy consumption, improving the fruit and vegetable drying efficiency and improving the storage fruit and vegetable quality.

[0056] When the temperature t s of the supply air S is less than 50℃, the single solid dehumidification mode is applied, that is, the process air P is subjected to the isenthalpic dehumidification through the solid dehumidification device air treatment channel 41; when the temperature t s of the supply air state point S is greater than 50℃, the dew point temperature t sl of the supply air S is greater than 10℃, the single refrigeration dehumidification mode is applied, that is, the process air is first cooled and dehumidified through the main evaporator 3, and then isohumid heated through the drying condenser 5; when the temperature t s of the supply air S is greater than 50℃, the dew point temperature t slWhen the temperature is less than 10℃, the solid dehumidification and refrigeration dehumidification combined mode is used, that is, the process air is cooled and dehumidified by the main evaporator 3, then is enthalpy dehumidified by the air treatment passage 41 of the solid dehumidification device, and finally is humidified by the drying condenser 5.

[0057] In the embodiment, the multi-operation-mode fruit and vegetable drying system further comprises a three-way valve 18 and a return air regulating valve 17. The first port of the three-way valve 18 is connected with the heat fluid outlet of the sensible heat recovery plate heat exchanger 7. The second port of the three-way valve 18 is connected with the second port of the return air regulating valve 17. The third port of the three-way valve 18 is connected with the external air. The first port of the return air regulating valve 17 is connected with the first port of the second air valve 20 and the first port of the first air valve 19 respectively.

[0058] In the embodiment, the indoor air R in the drying chamber 6 is sent into the sensible heat recovery plate heat exchanger 7 to exchange sensible heat with the outdoor fresh air F. The indoor air R is cooled after heat exchange, and the cooled air is marked as return air H. The outdoor fresh air F is heated after heat exchange, and the heated air is marked as regeneration air Z. The regeneration air Z is sent into the regeneration condenser 9 and the electric heating auxiliary device 10 in sequence, so that the regeneration of the adsorbent in the air regeneration passage 42 of the solid dehumidification device is realized, and the regeneration exhaust fan 11 is used to discharge the air to the outside.

[0059] In the embodiment, the multi-operation-mode fruit and vegetable drying system further comprises a second fresh air fan 8 and a fifth temperature and humidity detection device 27. The outlet of the second fresh air fan 8 is connected with the cold fluid inlet of the sensible heat recovery plate heat exchanger 7, and is used to send the external air into the sensible heat recovery plate heat exchanger 7. The fifth temperature and humidity detection device 27 is arranged at the inlet of the second fresh air fan 8, and is used to detect the temperature and humidity of the air entering the second fresh air fan 8.

[0060] In the embodiment, the adjusting system adjusts the operation mode by monitoring the temperature and humidity of each state point. By comparing the humidity of the outdoor fresh air F and the indoor air R, the process air is selected to be the fresh air F or the return air H. When the humidity of the fresh air F is small, the full fresh air system is used, the fresh air regulating valve 2 is opened, the return air regulating valve 17 is closed, and the three-way valve 18 is opened to discharge part of the return air, so as to balance the indoor air pressure. When the humidity of the indoor air R is small, the full return air system is used, the return air regulating valve 17 is opened, the fresh air regulating valve 2 and the three-way valve 18 are closed.

[0061] In the embodiment, the multi-operation-mode fruit and vegetable drying system further comprises a regeneration exhaust fan 11. The inlet of the regeneration exhaust fan 11 is connected with the outlet of the air regeneration passage 42 of the solid dehumidification device, and is used to discharge the air passing through the air regeneration passage 42 of the solid dehumidification device.

[0062] In the embodiment, the multi-operation mode fruit and vegetable drying system further comprises a first electromagnetic valve 14, a second electromagnetic valve 15 and an auxiliary evaporator 16, a first port of the first electromagnetic valve 14 is connected with the working medium outlet of the main evaporator 3, a second port of the first electromagnetic valve 14 is connected with the working medium inlet of the variable frequency compressor 12, a first port of the second electromagnetic valve 15 is connected with the working medium outlet of the main evaporator 3, a second port of the second electromagnetic valve 15 is connected with the working medium inlet of the auxiliary evaporator 16, and the working medium outlet of the auxiliary evaporator 16 is connected with the working medium inlet of the variable frequency compressor 12.

[0063] In the embodiment, after the working medium absorbs heat in the main evaporator 3, the low-temperature and low-pressure saturated steam is adiabatically compressed by the variable frequency compressor 12 to become high-temperature and high-pressure superheated steam. The variable frequency compressor 12 works on the working medium to change the thermodynamic state of the working medium. After adiabatic compression, the superheated steam passes through the drying condenser 5 and the regeneration condenser 9 in turn, and the working medium is condensed to become saturated liquid. Then, the working medium is throttling expanded by the expansion valve 13 to become low-temperature and low-pressure wet steam. After throttling expansion, the gas-liquid mixed working medium is evaporated to become saturated steam by the main evaporator 3 and the auxiliary evaporator 16. When the required refrigerating capacity of the main evaporator 3 is large, the first electromagnetic valve 14 is opened and the second electromagnetic valve 15 is closed; when the required refrigerating capacity of the main evaporator 3 is small, the second electromagnetic valve 15 is opened and the first electromagnetic valve 14 is closed. Then the working medium enters the compressor for circulation.

[0064] In the embodiment, the multi-operation mode fruit and vegetable drying system further comprises a third air valve 21 and a fourth air valve 22, a first port of the third air valve 21 is connected with the air outlet of the main evaporator 3, a second port of the third air valve 21 is connected with the air inlet of the drying condenser 5, a first port of the fourth air valve 22 is connected with the air outlet of the main evaporator 3, and a second port of the fourth air valve 22 is connected with the air inlet of the air handling passage 41 of the solid dehumidification device.

[0065] In the embodiment, the multi-operation mode fruit and vegetable drying system further comprises a first fresh air fan 1, a fresh air regulating valve 2 and a first temperature and humidity detection device 23, a second port of the fresh air regulating valve 2 is connected with a first port of the first air valve 19, a first port of the second air valve 20 and a first port of the return air regulating valve 17 respectively, an air outlet of the first fresh air fan 1 is connected with a first port of the fresh air regulating valve 2, and the first temperature and humidity detection device 23 is arranged at an air inlet of the first fresh air fan 1 and used for detecting the temperature and humidity of the air entering the first fresh air fan 1.

[0066] In the embodiment, the multi-operation mode fruit and vegetable drying system further comprises an expansion valve 13, a first port of the expansion valve 13 being connected with the working medium outlet of the regeneration condenser 9, and a second port of the expansion valve 13 being connected with the working medium inlet of the main evaporator 3.

[0067] The multi-operation mode fruit and vegetable drying system comprises three operation modes, i.e., a single solid dehumidification mode, a single refrigeration dehumidification mode, and a combined solid dehumidification and refrigeration dehumidification mode.

[0068] As shown in Figure 2 , the single solid dehumidification mode is applied when the temperature t s of the supply air state point S is less than 50℃. The specific implementation is as follows: by comparing the humidity of the outdoor fresh air F and the indoor air R, it is determined whether the process air P is the fresh air F or the return air H. When the humidity of the fresh air F is relatively small, a full fresh air system is adopted, the fresh air regulating valve 2 is opened, the return air regulating valve 17 is closed, and the three-way valve 18 is opened to discharge part of the return air, so as to maintain the indoor air pressure balance. When the humidity of the indoor air R is relatively small, a full return air system is adopted, the return air regulating valve 17 is opened, and the fresh air regulating valve 2 and the three-way valve 18 are closed. The first air valve 19, the third air valve 21, and the fourth air valve 22 are closed, and the second air valve 20 is opened. The process air P is dehumidified through the enthalpy dehumidification of the solid dehumidification device air treatment channel 41, and the low-humidity air is sent into the drying chamber 6 to dry the fruits and vegetables. The outdoor fresh air F enters the sensible heat recovery plate heat exchanger 7 through the second fresh air fan 8, and exchanges sensible heat with the indoor air R. After the sensible heat exchange, the regeneration air Z passes through the regeneration condenser 9 and the electric heating auxiliary device 10 in sequence, is heated to the regeneration temperature of the adsorbent in the solid dehumidification device air regeneration channel 42, and then the waste heat of the regenerated adsorbent is discharged to the outdoor. In the single solid dehumidification mode, the regeneration condenser 9 is mainly used to heat the regeneration air Z, so as to reduce the energy consumption of the solid dehumidification device air regeneration channel 42 for adsorbent regeneration.

[0069] As shown in Figure 3 , the single refrigeration dehumidification mode is applied when the temperature t s of the supply air state point S is greater than 50℃, and the dew point temperature t slWhen the temperature is above 10℃, a separate refrigeration and dehumidification mode is applied. Specifically, the humidity of the outdoor fresh air (F) and indoor air (R) is compared to determine whether the treated air (P) is fresh air (F) or return air (H). When the humidity of the fresh air (F) is low, a 100% fresh air system is used. The fresh air regulating valve 2 is opened, the return air regulating valve 17 is closed, and the three-way valve 18 is opened to exhaust some of the return air, maintaining indoor air pressure balance. When the humidity of the indoor air (R) is low, a full return air system is used. The return air regulating valve 17 is opened, and the fresh air regulating valve 2 and the three-way valve 18 are closed. The second air valve 20 and the fourth air valve 22 are closed, and the first air valve 19 and the third air valve 21 are opened. The treated air (P) is cooled and dehumidified by the main evaporator 3, then heated to a constant humidity by the drying condenser 5, and finally sent into the drying chamber 6 to dry fruits and vegetables. In the standalone refrigeration and dehumidification mode, the main evaporator 3 and the drying condenser 5 are mainly used. When the cooling capacity required by the main evaporator 3 is large, the first solenoid valve 14 is opened and the second solenoid valve 15 is closed, so that the working medium does not pass through the auxiliary evaporator 16. When the cooling capacity required by the main evaporator 3 is small, the second solenoid valve 15 is opened and the first solenoid valve 14 is closed, so that a part of the working medium passes through the auxiliary evaporator 16.

[0070] like Figure 4 As shown, the combined solid dehumidification and refrigeration dehumidification mode is when the temperature t at the air supply state point S is... s When the temperature is greater than 50℃, the dew point temperature t at the air supply state point S is... slWhen the temperature is less than 10℃, the solid dehumidification and refrigeration dehumidification combined mode is applied. The specific implementation is: by comparing the humidity of outdoor fresh air F and indoor air R, the processed air P is selected to be fresh air F or return air H. When the humidity of fresh air F is small, the full fresh air system is adopted, the fresh air adjusting valve 2 is opened, the return air adjusting valve 17 is closed, and the three-way valve 18 is opened to discharge part of the return air to maintain the indoor air pressure balance. When the humidity of indoor air R is small, the full return air system is adopted, the return air adjusting valve 17 is opened, and the fresh air adjusting valve 2 and the three-way valve 18 are closed. The second air valve 20 and the third air valve 21 are closed, the first air valve 19 and the fourth air valve 22 are opened, the processed air P is first cooled and dehumidified through the main evaporator 3, then is isenthalpic dehumidified through the solid dehumidification device air treatment channel 41, and finally is isohumid heated by the drying condenser 5, and is sent into the drying chamber 6 to dry the fruits and vegetables. The outdoor fresh air F enters the sensible heat recovery plate heat exchanger 7 through the second fresh air fan 8, and exchanges sensible heat with the indoor air R. After the sensible heat exchange, the regeneration air Z passes through the regeneration condenser 9 and the electric heating auxiliary device 10 in sequence, is heated to the regeneration temperature of the adsorbent in the solid dehumidification device air regeneration channel 42, and then the waste heat of the regenerated adsorbent is discharged to the outdoor. In the solid dehumidification and refrigeration dehumidification combined mode, the main evaporator 3, the drying condenser 5 and the regeneration condenser 9 are mainly used. When the required refrigerating capacity of the main evaporator 3 is large, the first electromagnetic valve 14 is opened and the second electromagnetic valve 15 is closed, so that the working medium does not pass through the auxiliary evaporator 16; when the required refrigerating capacity of the main evaporator is small, the second electromagnetic valve 15 is opened and the first electromagnetic valve 14 is closed, so that part of the working medium passes through the auxiliary evaporator 16. The regeneration air Z is heated by the regeneration condenser 9, which can reduce the energy consumption of the solid dehumidification device air regeneration channel 42 for adsorbent regeneration.

[0071] The application also discloses a multi-operation-mode fruit and vegetable drying method.

[0072] Step one: the third temperature and humidity detection device 25 in the multi-operation-mode fruit and vegetable drying system is used to detect the temperature and humidity of the air entering the drying chamber 6.

[0073] Step two: the operation mode is selected according to the detection result of the third temperature and humidity detection device 25.

[0074] When the temperature t detected by the third temperature and humidity detection device 25 is less than 10℃, the solid dehumidification and refrigeration dehumidification combined mode is applied. s When the temperature t detected by the third temperature and humidity detection device 25 is less than 50℃, the separate solid dehumidification mode is applied, that is, the first air valve 19, the third air valve 21 and the fourth air valve 22 are closed, and the second air valve 20 is opened, so that the air is isenthalpic dehumidified through the solid dehumidification device air treatment channel 41, and the low-humidity air is sent into the drying chamber 6 to dry the fruits and vegetables.

[0075] When the temperature t detected by the third temperature and humidity detection device 25 is greater than 50℃, the dew point temperature t s is greater than 50℃.sl When the temperature t is greater than 10℃, the single refrigeration dehumidification mode is applied, i.e. the second air valve 20 and the fourth air valve 22 are closed, the first air valve 19 and the third air valve 21 are opened, the air is cooled and dehumidified by the main evaporator 3, then heated by the condenser 5 for drying, and then sent into the drying chamber 6 to dry the fruits and vegetables.

[0076] When the temperature t s When the temperature t is greater than 50℃, the dew point temperature t sl When the temperature t is less than 10℃, the solid dehumidification and refrigeration dehumidification combined mode is applied, i.e. the second air valve 20 and the third air valve 21 are closed, the first air valve 19 and the fourth air valve 22 are opened, the air is cooled and dehumidified by the main evaporator 3, then dehumidified by the solid dehumidification device air treatment channel 41, finally heated by the condenser 5 for drying, and then sent into the drying chamber 6 to dry the fruits and vegetables.

[0077] In the embodiment, the first humidity detection device 23 and the fourth humidity detection device 26 are used to detect the air temperature and humidity in the respective air treatment channels in the single solid dehumidification mode, the single refrigeration dehumidification mode and the solid dehumidification and refrigeration dehumidification combined mode.

[0078] When the humidity detected by the first humidity detection device 23 is greater than the humidity detected by the fourth humidity detection device 26, the full return air system is applied, i.e. the fresh air regulating valve 2 and the three-way valve 18 are closed, and the return air regulating valve 17 is opened.

[0079] When the humidity detected by the first humidity detection device 23 is less than the humidity detected by the fourth humidity detection device 26, the full fresh air system is applied, i.e. the return air regulating valve 17 is closed, and the fresh air regulating valve 2 and the three-way valve 18 are opened.

[0080] The above description is only a preferred embodiment of the present application, and does not limit the present application in any way. Any simple modification, change and equivalent structural transformation of the above embodiment according to the technical essence of the present application are still within the protection scope of the technical solution of the present application.

Claims

1. A multi-operation mode fruit and vegetable drying system which dries fruit and vegetables in a drying chamber (6) by adjusting the temperature and humidity of the air supplied into the drying chamber (6), characterized in that, The application relates to a solid dehumidification system, which comprises a solid dehumidification device, a sensible heat recovery plate heat exchanger (7), a regeneration condenser (9) and an electric heating auxiliary (10), the solid dehumidification device comprises a solid dehumidification device air treatment channel (41) and a solid dehumidification device air regeneration channel (42), the air outlet of the solid dehumidification device air treatment channel (41) is communicated with the air inlet of a drying chamber (6) and is used for sending air dehumidified by the solid dehumidification device air treatment channel into the drying chamber (6), the hot fluid air inlet of the sensible heat recovery plate heat exchanger (7) is communicated with the air outlet of the drying chamber (6), the cold fluid air inlet of the sensible heat recovery plate heat exchanger (7) is communicated with external air, the cold fluid air outlet of the sensible heat recovery plate heat exchanger (7) is communicated with the air inlet of the regeneration condenser (9), the air outlet of the regeneration condenser (9) is communicated with the air inlet of the electric heating auxiliary (10), and the air outlet of the electric heating auxiliary (10) is communicated with the air inlet of the solid dehumidification device air regeneration channel (42). The application further relates to a refrigeration dehumidification system, which comprises a variable frequency compressor (12), a drying condenser (5) and a main evaporator (3), the working medium outlet of the variable frequency compressor (12) is communicated with the working medium inlet of the drying condenser (5), the working medium outlet of the drying condenser (5) is communicated with the working medium inlet of the regeneration condenser (9), the working medium outlet of the regeneration condenser (9) is communicated with the first port of an expansion valve (13), the second port of the expansion valve (13) is communicated with the working medium inlet of the main evaporator (3), the working medium outlet of the main evaporator (3) is communicated with the working medium inlet of the variable frequency compressor (12), the air inlet of the main evaporator (3) is communicated with external air, the air outlet of the main evaporator (3) is communicated with the air inlet of the drying condenser (5), and the air outlet of the drying condenser (5) is communicated with the air inlet of the drying chamber (6). ​ The adjusting system comprises a second temperature and humidity detection device (24), a first air valve (19), a second air valve (20), a third temperature and humidity detection device (25) and a fourth temperature and humidity detection device (26), the second port of the first air valve (19) is communicated with the air inlet of the main evaporator (3), the first port of the first air valve (19) is communicated with the outside air, the second port of the second air valve (20) is communicated with the air inlet of the solid dehumidification device air treatment channel (41), the first port of the second air valve (20) is communicated with the outside air, the second temperature and humidity detection device (24) is arranged on the end where the first air valve (19) and the second air valve (20) are communicated with the outside air, and is used for detecting the temperature and humidity of the air entering the first air valve (19) and the second air valve (20), the third temperature and humidity detection device (25) is arranged at the air inlet of the drying chamber (6), and is used for detecting the temperature and humidity of the air entering the drying chamber (6), and the fourth temperature and humidity detection device (26) is arranged at the air outlet of the drying chamber (6), and is used for detecting the temperature and humidity of the air coming out of the drying chamber (6); The multi-operation mode fruit and vegetable drying system further comprises a third air valve (21) and a fourth air valve (22), the first port of the third air valve (21) is communicated with the air outlet of the main evaporator (3), the second port of the third air valve (21) is communicated with the air inlet of the drying condenser (5), the first port of the fourth air valve (22) is communicated with the air outlet of the main evaporator (3), and the second port of the fourth air valve (22) is communicated with the air inlet of the solid dehumidification device air treatment channel (41).

2. A multi-operating mode fruit and vegetable drying system as claimed in claim 1, characterized in that: The multi-operation mode fruit and vegetable drying system further comprises a three-way valve (18) and a return air adjusting valve (17), the first port of the three-way valve (18) is communicated with the hot fluid air outlet of the sensible heat recovery plate heat exchanger (7), the second port of the three-way valve (18) is communicated with the second port of the return air adjusting valve (17), the third port of the three-way valve (18) is communicated with the outside air, and the first port of the return air adjusting valve (17) is communicated with the first port of the second air valve (20) and the first port of the first air valve (19) respectively.

3. A multi-operating mode fruit and vegetable drying system as claimed in claim 2, characterized in that: The multi-operation mode fruit and vegetable drying system further comprises a second fresh air fan (8) and a fifth temperature and humidity detection device (27), the air outlet of the second fresh air fan (8) is communicated with the cold fluid air inlet of the sensible heat recovery plate heat exchanger (7), and is used for sending the outside air into the sensible heat recovery plate heat exchanger (7), and the fifth temperature and humidity detection device (27) is arranged at the air inlet of the second fresh air fan (8), and is used for detecting the temperature and humidity of the air entering the second fresh air fan (8).

4. A multi-operating mode fruit and vegetable drying system as claimed in claim 3, characterized in that: The multi-operation mode fruit and vegetable drying system further comprises a regeneration exhaust fan (11), the air inlet of the regeneration exhaust fan (11) is communicated with the air outlet of the solid dehumidification device air regeneration channel (42), and is used for discharging the air passing through the solid dehumidification device air regeneration channel (42).

5. A multi-operating mode fruit and vegetable drying system as claimed in claim 4, characterized in that: The multi-operation mode fruit and vegetable drying system further comprises a first electromagnetic valve (14), a second electromagnetic valve (15) and an auxiliary evaporator (16), a first port of the first electromagnetic valve (14) is connected with a working medium outlet of the main evaporator (3), a second port of the first electromagnetic valve (14) is connected with a working medium inlet of the variable frequency compressor (12), a first port of the second electromagnetic valve (15) is connected with the working medium outlet of the main evaporator (3), a second port of the second electromagnetic valve (15) is connected with a working medium inlet of the auxiliary evaporator (16), and a working medium outlet of the auxiliary evaporator (16) is connected with the working medium inlet of the variable frequency compressor (12).

6. A multi-operating mode fruit and vegetable drying system as claimed in claim 5, characterized in that: The multi-operation mode fruit and vegetable drying system further comprises a first fresh air fan (1), a fresh air regulating valve (2) and a first temperature and humidity detection device (23), a second port of the fresh air regulating valve (2) is connected with a first port of a first air valve (19), a first port of a second air valve (20) and a first port of a return air regulating valve (17) respectively, an air outlet of the first fresh air fan (1) is connected with a first port of the fresh air regulating valve (2), and the first temperature and humidity detection device (23) is arranged at an air inlet of the first fresh air fan (1) and is used for detecting temperature and humidity of air entering the first fresh air fan (1).

7. A multi-operating mode method of drying fruits and vegetables, characterized in that, The method comprises the following steps: The third temperature and humidity detection device (25) in the multi-operation mode fruit and vegetable drying system in claim 6 is used to detect temperature and humidity of air entering the drying chamber (6); An operation mode is selected according to a detection result of the third temperature and humidity detection device (25); When the third temperature and humidity detection device (25) detects a temperature t s When the temperature t is less than 50℃, the single solid dehumidification mode is applied, i.e. the first air valve (19), the third air valve (21) and the fourth air valve (22) are closed, the second air valve (20) is opened, the air is enthalpy dehumidified through the solid dehumidification device air treatment channel (41), and the low-humidity air is sent into the drying chamber (6) to dry the fruits and vegetables. When the temperature t s greater than 50℃, the dew point temperature t sl greater than 10℃, the single refrigeration dehumidification mode is applied, i.e. the second air valve (20) and the fourth air valve (22) are closed, the first air valve (19) and the third air valve (21) are opened, the air is cooled and dehumidified by the main evaporator (3), then heated by the condenser (5) for drying, etc. to be humidified, and then sent into the drying chamber (6) to dry the fruits and vegetables; When the temperature t s greater than 50℃, the dew point temperature t sl less than 10℃, the solid dehumidification and refrigeration dehumidification combined mode is applied, i.e. the second air valve (20) and the third air valve (21) are closed, the first air valve (19) and the fourth air valve (22) are opened, the air is first cooled and dehumidified by the main evaporator (3), then is enthalpy dehumidified by the solid dehumidification device air treatment channel (41), finally is humidified by the drying condenser (5), and is sent into the drying chamber (6) to dry the fruits and vegetables.

8. A multi-operating mode fruit and vegetable drying method according to claim 7, characterized in that: In the single solid dehumidification mode, the single refrigeration dehumidification mode and the combined solid dehumidification and refrigeration dehumidification mode, the first temperature and humidity detection device (23) and the fourth temperature and humidity detection device (26) are used to detect temperature and humidity of air passing through each air; When humidity detected by the first temperature and humidity detection device (23) is greater than humidity detected by the fourth temperature and humidity detection device (26), a full return air system is applied, that is, the fresh air regulating valve (2) and the three-way valve (18) are closed, and the return air regulating valve (17) is opened; When humidity detected by the first temperature and humidity detection device (23) is less than humidity detected by the fourth temperature and humidity detection device (26), a full fresh air system is applied, that is, the return air regulating valve (17) is closed, and the fresh air regulating valve (2) and the three-way valve (18) are opened.

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