WO2023024636A1

WO2023024636A1 - Drying unit control method and drying system

Info

Publication number: WO2023024636A1
Application number: PCT/CN2022/096783
Authority: WO
Inventors: 杨公增
Original assignee: 青岛海尔空调电子有限公司; 青岛海尔空调器有限总公司; 海尔智家股份有限公司
Priority date: 2021-08-25
Filing date: 2022-06-02
Publication date: 2023-03-02
Also published as: CN113865322A; CN113865322B

Abstract

A drying unit control method. The method comprises: when a dry bulb temperature in a curing barn (1) is lower than a temperature threshold value, if a wet bulb temperature in the curing barn (1) is lower than a low humidity threshold value, heating an airflow in a main air duct (4) by means of a first condenser (2-2) and a second condenser (3-2); if the wet bulb temperature in the curing barn is higher than or equal to the low humidity threshold value and is lower than a high humidity threshold value, turning on a dehumidification throttling apparatus (8), operating an inner dehumidification circulation fan (5-4), and controlling the opening and closing of an inner circulation air supply port (5-2), a moisture discharge port (5-3) and a fresh air port (4-3) according to the magnitude relationship between an air output dry bulb temperature of the inner dehumidification circulation fan (5-4) and a dry bulb temperature in an external environment; and if the wet bulb temperature in the curing barn is higher than or equal to the high humidity threshold value, turning on the dehumidification throttling apparatus (8), operating the inner dehumidification circulation fan (5-4), closing the inner circulation air supply port (5-2), opening the moisture discharge port (5-3), and opening the fresh air port (4-3). A drying unit control system executes the drying unit control method.

Description

A drying unit control method and drying system

technical field

The invention belongs to the technical field of drying, and in particular relates to a drying unit control method and a drying system.

Background technique

With the proposal of carbon peak, carbon neutrality and dual carbon goals, the country pays more and more attention to the promotion and implementation of energy conservation and emission reduction. For the agricultural product processing industry, air energy heat pumps are gradually being promoted nationwide to replace coal-fired barns, which is an important measure for the country's energy-saving and emission-reduction work.

technical problem

At present, the air energy heat pump tobacco drying unit in the industry is usually based on the original coal-fired barn, the original coal-fired boiler is removed, and the air energy heat pump unit is used to replace it, that is, the heat pump unit is used to absorb the external ambient air through the reverse Carnot cycle. The heat energy in the curing room is used to heat and dry the tobacco in the curing room; the moisture removal part of the curing room usually borrows the structure of the original curing room, and the high-grade heat source with high temperature and high humidity discharged during the tobacco drying process is not used, resulting in The overall operating energy consumption is still high, and the energy saving effect cannot meet the expected requirements.

technical solution

The invention provides a drying unit control method, which solves the problem of high energy consumption in the prior art.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions to achieve:

A method for controlling a drying unit, comprising:

A first heat pump unit, which includes a first compressor, a first condenser, a first throttling device, and a first evaporator;

The second heat pump unit includes a second compressor, a second condenser, a second throttling device, and a second evaporator;

The main air duct has a fresh air outlet, and a main circulation fan is arranged in it;

The dehumidification air duct has an internal circulation air supply port connected to the main air duct and a moisture discharge port connected to the external space; the dehumidification air duct is provided with an internal dehumidification circulation fan, an internal dehumidification evaporator, and a heat pipe evaporation side heat exchanger; A dehumidification throttling device is arranged on the connecting pipeline between the internal dehumidification evaporator and the first condenser;

The control methods include:

Obtain the dry bulb temperature in the barn, and when the dry bulb temperature is less than the temperature threshold, perform the following operations:

If the wet bulb temperature in the barn is lower than the low humidity threshold, the first compressor and the second compressor are controlled to start, the first throttling device and the second throttling device are turned on, the dehumidification throttling device is turned off, and the internal dehumidification circulating fan is turned off. The main circulation fan is running; the internal circulation air supply outlet, humidity exhaust outlet and fresh air outlet are all closed;

If the low humidity threshold ≤ the wet bulb temperature in the barn < the high humidity threshold, the first compressor and the second compressor are controlled to start, the first throttling device is closed, the second throttling device and the dehumidification throttling device are turned on, and the internal dehumidification Circulation fan and main circulation fan are running; according to the relationship between the dry bulb temperature of the air outlet of the internal dehumidification circulation fan and the dry bulb temperature of the external environment, the switches of the internal circulation air supply port, moisture discharge port and fresh air port are controlled;

If the wet bulb temperature in the barn is greater than or equal to the high humidity threshold, control the first compressor and the second compressor to start, the first throttling device to close, the second throttling device, the dehumidification throttling device to open, the internal dehumidification circulation fan, the main The circulation fan is running; the internal circulation air supply port is closed, the moisture exhaust port is opened, and the fresh air port is opened.

Further, according to the relationship between the dry bulb temperature of the air outlet of the internal dehumidification circulating fan and the dry bulb temperature of the external environment, the control of the switch of the internal circulation air supply port, the moisture discharge port, and the fresh air port specifically includes:

If Tc≥Ta, the internal circulation air supply port is opened, the moisture discharge port is closed, and the fresh air port is closed;

If Tc<Ta, the internal circulation air supply port is closed, the moisture discharge port is opened, and the fresh air port is opened;

Among them, Tc is the dry bulb temperature of the internal dehumidification circulating fan; Ta is the dry bulb temperature of the external environment.

Still further, when the dry bulb temperature in the barn is greater than or equal to the temperature threshold, perform the following operations:

Control the first compressor, the second compressor, the first throttling device, the second throttling device, the dehumidification throttling device, and the internal dehumidification circulation fan to be closed, and the main circulation fan is running;

When the wet bulb temperature in the barn is lower than the low humidity threshold, the internal circulation air supply port, moisture discharge port and fresh air port are all closed;

When the low humidity threshold ≤ the wet bulb temperature in the barn < the high humidity threshold, keep the internal circulation air supply port, moisture discharge port and fresh air port on and off;

When the wet bulb temperature in the barn is greater than or equal to the high humidity threshold, the internal circulation air supply port is closed, the moisture discharge port is opened, and the fresh air port is opened.

Furthermore, temperature threshold = Tg0-ΔTg;

Low humidity threshold = Ts0-ΔTs;

High humidity threshold = Ts0 + ΔTs;

Among them, Tg0 is the target dry bulb temperature; ΔTg is the hysteresis of the target dry bulb control accuracy;

Ts0 is the target wet bulb temperature; ΔTs is the hysteresis of the target wet bulb control accuracy.

Still further, a heat pipe condensation side heat exchanger is provided on the windward side of the first evaporator, and the position of the heat pipe condensation side heat exchanger is higher than that of the heat pipe evaporation side heat exchanger; the heat pipe evaporation side heat exchanger The top of the heat pipe is connected to the top of the heat pipe condensation side heat exchanger through a gas pipe connection, and the bottom of the heat pipe condensation side heat exchanger is connected to the bottom of the heat pipe evaporation side heat exchanger through a liquid pipe connection.

Further, the heat exchanger on the condensation side of the heat pipe and the heat exchanger on the evaporation side of the heat pipe both include a liquid collector, a gas collector, and several branch pipes;

The air collecting pipe is located above the liquid collecting pipe; each of the branch pipes is arranged vertically, one end of each of the branch pipes is inserted into the liquid collecting pipe, and the other end of each of the branch pipes is inserted into the air collecting pipe ; Several branch pipes are arranged at equal intervals; the upper outer wall of the branch pipe is provided with fins;

The air collector of the heat pipe evaporation side heat exchanger is connected to the air collector of the heat pipe condensation side heat exchanger through the air pipe joint;

The liquid collecting pipe of the heat exchanger on the evaporating side of the heat pipe is connected to the liquid collecting pipe of the heat exchanger on the condensing side of the heat pipe through the connecting pipe of the liquid pipe.

Still further, a circulating pump is arranged on the connecting pipe of the liquid pipe.

Further, the heat exchanger on the condensation side of the heat pipe and the heat exchanger on the evaporation side of the heat pipe are both microchannel heat pipe heat exchangers.

Still further, the internal dehumidification evaporator and the heat pipe evaporation side heat exchanger are arranged vertically, the top of the internal dehumidification evaporator is flush with the top of the heat pipe evaporation side heat exchanger, and the bottom of the internal dehumidification evaporator It is flush with the bottom of the heat exchanger on the evaporation side of the heat pipe; the inner dehumidification evaporator is in contact with the leeward surface of the heat exchanger on the evaporation side of the heat pipe.

A drying system comprising:

The barn is equipped with a temperature and humidity sensor for collecting the dry bulb temperature and wet bulb temperature in the barn;

A drying unit, the controller of which executes the drying unit control method.

Beneficial effect

Compared with the prior art, the advantages and positive effects of the present invention are: the drying unit control method and the drying system of the present invention, when the dry bulb temperature in the oven < temperature threshold, and the wet bulb temperature in the oven < When the humidity threshold is low, the airflow in the main air duct is heated through the first condenser and the second condenser to realize heating and heating of the barn; when the dry bulb temperature in the barn is lower than the temperature threshold, and the low humidity threshold ≤When the wet bulb temperature in the barn is lower than the high humidity threshold, the dehumidification throttling device is turned on, the internal dehumidification circulation fan is running, and the internal circulation air supply port is controlled according to the relationship between the dry bulb temperature of the internal dehumidification circulation fan and the dry bulb temperature of the external environment , dehumidification outlet, and fresh air outlet switch; the airflow is dehumidified through the heat pipe evaporation side heat exchanger and the internal dehumidification evaporator, and the temperature of the airflow is raised through the first condenser and the second condenser to improve the dry bulb in the barn Temperature; When the dry bulb temperature in the barn is less than the temperature threshold and the wet bulb temperature in the barn is greater than or equal to the high humidity threshold, the dehumidification throttling device will be turned on, the internal dehumidification circulation fan will run, the internal circulation air supply port will be closed, and the moisture discharge port will be opened. , the new air outlet is opened; the dry air from the external environment is introduced through the new air outlet, and the high-humidity air in the barn flows through the heat pipe evaporator side heat exchanger for pre-cooling, and after the dehumidification heat is recovered by the internal dehumidification evaporator, it is discharged to the oven through the dehumidification outlet. In the external environment of the drying unit, reduce the wet bulb temperature in the barn; heat up the airflow in the main air duct through the first condenser and the second condenser to increase the dry bulb temperature in the barn; therefore, the present invention The control method of the drying unit and the drying system not only realize the temperature and humidity control of the barn, but also perform heat recovery through the heat pipe heat exchanger, thereby achieving the purpose of saving energy and reducing consumption.

Description of drawings

Fig. 1 is a structural representation of an embodiment of the drying system proposed by the present invention;

Fig. 2 is a schematic structural view of an embodiment of the drying unit in Fig. 1;

Fig. 3 is a schematic diagram of an embodiment of the drying system proposed by the present invention;

Fig. 4 is a schematic structural view of an embodiment of the heat pipe heat exchanger in Fig. 2;

Fig. 5 is a schematic structural view of an embodiment of the heat exchanger on the evaporation side of the heat pipe in Fig. 4;

Fig. 6 is a schematic structural view of an embodiment of the heat exchanger on the condensation side of the heat pipe in Fig. 4;

Fig. 7 is a flow chart of an embodiment of the drying unit control method proposed by the present invention.

Reference signs:

1. Baking room; 1-1, air duct; 1-2, temperature and humidity sensor; 1-3, bracket; 1-4, tobacco leaves;

2-1. The first compressor; 2-2. The first condenser; 2-3. The first throttling device; 2-4. The first evaporator; 2-5. The first external fan;

3-1, the second compressor; 3-2, the second condenser; 3-3, the second throttling device; 3-4, the second evaporator; 3-5, the second external fan;

4. Main air duct; 4-1, main return air outlet; 4-2, main air supply outlet; 4-3, fresh air outlet; 4-4, auxiliary return air outlet; 4-5, main circulation fan;

5. Dehumidification air duct; 5-1. Dehumidification return air outlet; 5-2. Internal circulation air supply outlet; 5-3. Dehumidification outlet; 5-4. Internal dehumidification circulation fan;

6. Internal temperature sensor;

7. Internal dehumidification evaporator;

8. Dehumidification throttling device;

9. Heat exchanger on the evaporation side of the heat pipe; 9-1. Liquid collection pipe; 9-2. Gas collection pipe; 9-3. Branch pipe; 9-4. Fins; Liquid collecting pipe; 10-2, gas collecting pipe; 10-3, branch pipe; 10-4, fin;

11. Water tray; 12. Air pipe connection; 13. Liquid pipe connection.

Embodiments of the present invention

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

It should be noted that, in the description of the present invention, the terms "up", "down", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate directions or positions The terms of the relationship are based on the orientation or positional relationship shown in the drawings, which are for convenience of description only, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be interpreted as Limitations on the Invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and should not be understood as indicating or implying relative importance.

In addition, it should be noted that, in the description of the present invention, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a It is a detachable connection or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediary, and it may be the internal communication of two components. Those skilled in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

Aiming at the problem of high energy consumption of the current drying unit, the present invention proposes a drying unit control method and a drying system, which can control the temperature and humidity of the drying room, reduce energy consumption and save energy. Next, the drying unit control method and drying system of the present invention will be described in detail in conjunction with the accompanying drawings.

The drying system of this embodiment includes a drying room 1 and a drying unit, as shown in FIG. 1 .

The barn 1 has an air inlet, an air outlet, and an air duct 1-1. A bracket 1-3 is arranged in the air duct 1-1, and materials to be dried such as tobacco leaves 1-4 are arranged on the bracket 1-3. The air flow enters the air duct 1-1 through the air inlet, bakes the material, and then flows out of the barn 1 through the air outlet. A temperature and humidity sensor 1-2 is installed in the barn 1 to collect the dry bulb temperature and wet bulb temperature in the barn 1, and send the collected dry bulb temperature and wet bulb temperature to the controller of the drying unit .

The drying unit, the controller of which controls the operation of the drying unit according to the received dry bulb temperature and wet bulb temperature sent by the temperature and humidity sensor, and delivers gas meeting the temperature and humidity requirements to the barn 1 . The controller of the drying unit executes the drying unit control method of this embodiment.

The drying unit of this embodiment includes a first heat pump unit, a second heat pump unit, a main air duct 4, a dehumidification air duct 5, a heat pipe heat exchanger, an internal dehumidification evaporator 7, a controller, etc., see Fig. 2 to Fig. 6 shown.

The first heat pump unit includes a first compressor 2-1, a first condenser 2-2, a first throttling device 2-3, a first evaporator 2-4, etc. forming a refrigerant circulation pipeline; A first external fan 2-5 is provided outside the evaporator 2-4.

The second heat pump unit includes a second compressor 3-1, a second condenser 3-2, a second throttling device 3-3, a second evaporator 3-4, etc. forming a refrigerant circulation pipeline; The outside of the evaporator 3-4 is provided with a second external fan 3-5. The first compressor 2-1, the second compressor 3-1, the first evaporator 2-4, the second evaporator 3-4, the first external fan 2-5, and the second external fan 3-5 are all arranged in outside space. Driven by the first outdoor fan 2-5 and the second outdoor fan 3-5, the airflow in the external space first passes through the first evaporator 2-4, and then passes through the second evaporator 3-4. The first condenser 2 - 2 and the second condenser 3 - 2 are arranged in the main air duct 4 . The first condenser 2-2 is on the windward side of the second condenser 3-2, and the first evaporator 2-4 is on the windward side of the second evaporator 3-4.

The main air duct 4 has the main air return port 4-1, the auxiliary air return port 4-4, the fresh air port 4-3, and the main air supply port 4-2; the main air return port 4-1 communicates with the air outlet of the barn 1, and the main The air supply port 4-2 communicates with the air inlet of the barn 1; the fresh air port 4-3 communicates with the outside space, and the main air duct 4 is provided with a main circulation fan 4-5, a first condenser 2-2, and a second condenser 3 -2. The fresh air outlet 4-3 is provided with a fresh air damper for opening and closing the fresh air damper 4-3, and the controller controls the opening and closing of the fresh air damper. When the fresh air damper was opened, the fresh air port 4-3 was opened, and the air in the external space entered the main air passage 4 through the fresh air port 4-3. When the fresh air damper was closed, the fresh air port 4-3 was closed. Therefore, the fresh air damper is opened to introduce dry and high-temperature air from the external environment. The main circulation fan 4-5 rotates to drive the air in the main air channel 4 to deliver air to the barn 1 through the main air supply port 4-2. Driven by the main circulation fan 4-3, the airflow in the main air duct 4 first passes through the first condenser 2-2, then passes through the second condenser 3-2, and then enters the barn 1 through the main air supply port 4-2 .

The dehumidification air duct 5 has a dehumidification air return port 5-1, an internal circulation air supply port 5-2, and a moisture discharge port 5-3; the dehumidification return air port 5-1 communicates with the air outlet of the barn 1, and the internal circulation air supply port 5- 2 communicates with the auxiliary air return port 4-4 of the main air duct 4; the moisture discharge port 5-3 communicates with the external space; the internal circulation air supply port 5-2 is provided with an internal circulation damper for opening and closing the internal circulation air supply port 5 -2; Dehumidification outlet 5-3 is provided with a dehumidification damper for opening and closing the dehumidification outlet 5-3; dehumidification air duct 5 is provided with an internal dehumidification circulation fan 5-4, an internal dehumidification evaporator 7, and a heat pipe Evaporation side heat exchanger 9. The controller controls the opening and closing of the internal circulation air door. When the internal circulation air door is opened, the internal circulation air supply port 5-2 is opened, and the air in the dehumidification air duct 5 enters the main Inside the air duct 4. When the internal circulation damper was closed, the internal circulation air supply port 5-2 was closed. The controller controls the opening and closing of the dehumidification damper. When the dehumidification damper is opened, the dehumidification outlet 5-3 is opened, and the air in the dehumidification air duct 5 is discharged to the outside space through the dehumidification outlet 5-3. When the humidity discharge damper was closed, the moisture discharge port 5-3 was closed. Therefore, the dehumidification damper is opened to discharge the high-humidity air in the dehumidification air duct 5 .

The heat pipe heat exchanger includes a heat pipe evaporation side heat exchanger 9 and a heat pipe condensation side heat exchanger 10, the heat pipe evaporation side heat exchanger 9 is located in the dehumidification air duct 5 near the dehumidification return air outlet 5-1; the heat pipe condensation side heat exchanger The device 10 is located on the windward side of the first evaporator 2-4. The heat exchanger 9 on the evaporating side of the heat pipe and the heat exchanger 10 on the condensing side of the heat pipe are connected by pipelines. The liquid refrigerant in the heat exchanger 9 on the evaporating side of the heat pipe absorbs heat and evaporates into a gaseous state, and the gaseous refrigerant enters the heat exchanger on the condensing side of the heat pipe through the pipeline. 10. The gaseous refrigerant in the heat exchanger 10 on the condensing side of the heat pipe is condensed into a liquid state after being cooled, and the liquid refrigerant enters the heat exchanger 9 on the evaporating side of the heat pipe through the pipeline to complete a refrigerant cycle.

The inner dehumidification evaporator 7 is located in the dehumidification air duct 5, and the inner dehumidification evaporator 7 is located on the leeward side of the heat pipe evaporation side heat exchanger 9; the air pipe of the inner dehumidification evaporator 7 is connected to the air return pipe of the first compressor 2-1 The liquid pipe of the internal dehumidification evaporator 7 is connected to the liquid pipe of the first condenser 2-2, and a dehumidification throttling device 8 is arranged on the connecting pipeline between the internal dehumidification evaporator 7 and the first condenser 2-2.

A controller, which controls the first heat pump unit (the first compressor 2-1, the first throttling device 2-3, etc.), the second heat pump unit (the second compressor 3-1, the second throttling device 3-3, etc.), dehumidification throttling device 8, main circulation fan 4-5, internal dehumidification circulation fan 5-4, internal circulation damper, humidity exhaust damper, fresh air damper operation. The first throttling device 2-3, the second throttling device 3-3, and the dehumidification throttling device 8 are all electronic expansion valves, and the controller controls the operation of these three electronic expansion valves.

The drying unit control method in this embodiment mainly includes the following steps, as shown in FIG. 7 .

Step S1: Obtain the dry bulb temperature and wet bulb temperature in the barn.

Step S2: judging whether the dry bulb temperature in the barn is lower than the temperature threshold.

When the dry bulb temperature in the barn is lower than the temperature threshold, it means that the dry bulb temperature in barn 1 is low at this time, and it is necessary to turn on two heat pump units to heat up the air in barn 1. The wet bulb temperature in the room can be used to determine whether dehumidification treatment is required.

Therefore, when the dry bulb temperature in the barn is less than the temperature threshold:

If the wet bulb temperature in the barn is less than the low humidity threshold, step S3 is executed;

If the low humidity threshold ≤ the wet bulb temperature in the baking room < the high humidity threshold, execute step S4;

If the wet bulb temperature in the barn is greater than or equal to the high humidity threshold, step S5 is executed.

Step S3: If the wet-bulb temperature in the drying room is less than the low humidity threshold, it means that the wet-bulb temperature in the drying room is low, and there is no need for dehumidification action, and it is only necessary to heat up the drying room 1 and control the first compressor 2-1 Start, the second compressor 3-1 starts, the first throttling device 2-3 is opened, the second throttling device 3-3 is opened, the dehumidification throttling device 8 is closed, the internal dehumidification circulation fan 5-4 is closed, and the main circulation fan 4-5 operation; the internal circulation damper, the damp discharge damper, and the fresh air damper are all closed, that is, the internal circulation air supply port 5-2, the moisture discharge port 5-3, and the fresh air vent 4-3 are all closed. Through the first condenser 2-2 and the second condenser 3-2, the airflow in the main air duct 4 is heated up, so as to realize heat supply and temperature rise for the barn 1 .

Step S4: If the low humidity threshold ≤ the wet bulb temperature in the barn < the high humidity threshold, control the first compressor 2-1 to start, the second compressor 3-1 to start, the first throttling device 2-3 to close, and the second compressor 2-1 to start. The second throttling device 3-2 is opened, the dehumidification throttling device 8 is opened, the inner dehumidification circulation fan 5-4 runs, and the main circulation fan 4-5 runs; The relationship between the ambient dry bulb temperature controls the opening and closing of the internal circulation damper, humidity exhaust damper, and fresh air damper, and then realizes the control of the internal circulation air supply port 5-2 according to the relationship between the dry bulb temperature of the internal dehumidification circulation fan and the external environment dry bulb temperature , the switch of the moisture outlet 5-3 and the fresh air outlet 4-3.

In this embodiment, according to the relationship between the dry-bulb temperature of the air outlet of the internal dehumidification circulating fan and the dry-bulb temperature of the external environment, the switches of the internal circulation air supply port, the dehumidification port, and the fresh air port are controlled, specifically including the following steps:

S41: If Tc≥Ta, control the internal circulation air supply port 5-2 to open, the moisture discharge port 5-3 to close, and the fresh air port 4-3 to close. The wind blown by the internal dehumidification circulation fan 5-4 enters the main air duct 4 through the internal circulation air supply port 5-2 and the auxiliary return air port 4-4.

S42: If Tc<Ta, control the internal circulation air supply port 5-2 to close, the moisture discharge port 5-3 to open, and the fresh air port 4-3 to open. The cool air blown by the internal dehumidification circulation fan 5-4 is directly discharged out of the unit through the humidity discharge port 5-3, and the outside air with a higher temperature enters the main air duct 4 through the fresh air port 4-3, further realizing energy saving and reducing the overall temperature of the barn. energy consumption.

Through S41-S42, the switches of the air supply port, the humidity discharge port, and the fresh air port of the internal circulation are determined to save energy and reduce consumption, and the method is simple and easy to implement.

Step S5: If the wet bulb temperature in the barn is ≥ the high humidity threshold, it means that the wet bulb temperature in the barn is very high, control the first compressor 2-1 to start, the second compressor 3-1 to start, and the first throttling The device 2-3 is closed, the second throttling device 3-3 is opened, the dehumidification throttling device 8 is opened, the internal dehumidification circulation fan 5-4 is running, and the main circulation fan 4-5 is running; the internal circulation damper is controlled to be closed, and the dehumidification damper is opened , the fresh air damper is opened, and then the internal circulation air supply port 5-2 is controlled to be closed, the moisture discharge port 5-3 is opened, and the fresh air port 4-3 is opened. Introduce dry air from the external environment through the fresh air port 4-3, and pass the high-humidity air in the barn through the heat pipe evaporator side heat exchanger 9 for pre-cooling, and after the dehumidification heat is recovered by the internal dehumidification evaporator 7, it passes through the dehumidification port 5-3 It is discharged to the external environment of the drying unit, which can quickly reduce the wet bulb temperature in the barn, realize the rapid dehumidification function, and consume less energy.

If the first throttling device 2-3 is opened and the dehumidification throttling device 8 is opened, the high-temperature and high-pressure refrigerant discharged from the first compressor 2-1 enters the first condenser 2-2, and the refrigerant flowing out of the first condenser 2-2 Divided into two paths, one path of refrigerant flows to the first evaporator 2-4 through the first throttling device 2-3, and the refrigerant flowing out of the first evaporator 2-4 flows back to the first compressor 2-1; the other path The refrigerant flows to the inner dehumidification evaporator 7 through the dehumidification throttling device 8, and the refrigerant flowing out of the inner dehumidification evaporator 7 flows back to the first compressor 2-1.

When the first throttling device 2-3 is closed and the dehumidification throttling device 8 is opened, the high-temperature and high-pressure refrigerant discharged from the first compressor 2-1 enters the first condenser 2-2, and the refrigerant flowing out of the first condenser 2-2 All the refrigerant flows through the dehumidification throttling device 8 to the inner dehumidification evaporator 7, and the refrigerant flowing out of the inner dehumidification evaporator 7 flows back to the first compressor 2-1. In order to ensure the dehumidification effect, when dehumidification is required, the first throttling device 2-3 is controlled to be closed, and the dehumidification throttling device 8 is opened, so that all the refrigerant flowing out of the first condenser 2-2 flows to the dehumidification throttling device 8, and after dehumidification The throttling device 8 flows into the inner dehumidifying evaporator 7 .

When the main circulation fan 4-5 is in operation, the internal dehumidification circulation fan 5-4 is in operation, and the internal circulation damper is opened, part of the airflow flowing out from the air outlet of the barn 1 enters the main air duct 4 through the main return air outlet 4-1, and the other Part of the air enters the dehumidification air duct 5 through the dehumidification return air outlet 5-1. The airflow entering the dehumidification air duct 5 first exchanges heat with the heat exchanger 9 on the evaporating side of the heat pipe, and the heat exchanger 9 on the evaporating side of the heat pipe precools the airflow. After the inner dehumidification evaporator 7 cools down, the temperature of the airflow drops below the dew point temperature, and the surface of the inner dehumidification evaporator 7 condenses into water droplets; Along the dehumidification air duct 5, it flows through the internal circulation air supply port 5-2 to the auxiliary air return port 4-4, merges into the main air duct 4, and mixes with the airflow entering the main air duct 4 through the main return air port 4-1. After mixing The airflow in turn flows through the first condenser 2-2 and the second condenser 3-2, and exchanges heat with the refrigerant in the first condenser 2-2 and the second condenser 3-2, the temperature of the airflow increases, and then Enter the barn 1 through the main air supply port 4-2 to realize an air circulation.

The heat exchanger 10 on the condensation side of the heat pipe, the first evaporator 2-4, and the second evaporator 3-4 are installed in the external space, the first evaporator 2-4 is located on the windward side of the second evaporator 3-4, and the condensation side of the heat pipe The heat exchanger 10 is located on the windward side of the first evaporator 2-4, the first external fan 2-5 and the second external fan 3-5 are located on the leeward side of the second evaporator 2-4, and the first external fan 2-5 is located on the leeward side of the second evaporator 2-4. 5. Under the action of the second external fan 3-5, the external air first flows through the heat exchanger 10 on the condensation side of the heat pipe to cool the gaseous refrigerant in the heat exchanger 10 on the condensation side of the heat pipe. Since the ambient temperature of the external space is much lower than Therefore, the refrigerant in the heat exchanger 10 on the condensing side of the heat pipe can fully condense and dissipate heat, and improve the working efficiency of the heat pipe heat exchanger; when the outside air flows through the heat exchanger 10 on the condensing side of the heat pipe, it is heated, and the heated outside The air then flows through the first evaporator 2-4 and the second evaporator 3-4, which can effectively increase the evaporation temperature of the first evaporator 2-4 and the second evaporator 3-4, and realize the heat exchanger 10 on the condensation side of the heat pipe. Heat recovery improves the overall operating efficiency of the unit.

By setting the first condenser 2-2 and the second condenser 3-2 in the main air duct 4, and setting the heat pipe evaporation side heat exchanger 9 and the internal dehumidification evaporator 7 in the dehumidification air duct 5, through the heat pipe evaporation side heat exchange The heater 9 precools the air flow, the internal dehumidification evaporator 7 dehumidifies the air flow, and then heats the air flow through the first condenser 2-2 and the second condenser 3-2, and sends the dehumidified and heated gas into the barn to realize The dehumidification and high-efficiency heat recovery of the wind discharged from the barn 1 are realized, so as to achieve the purpose of further saving energy, saving energy and reducing consumption. By designing the moisture discharge port 5-3 and the fresh air port 4-3, the wet bulb temperature in the barn can be rapidly reduced, and the rapid dehumidification function can be realized. Moreover, the heat pipe condensation side heat exchanger 10 is located on the windward side of the first evaporator 2-4, the outside air is heated by the heat pipe condensation side heat exchanger 10 and then flows through the first evaporator 2-4 and the second evaporator 3 in sequence -4, can effectively increase the evaporation temperature of the first evaporator 2-4 and the second evaporator 3-4, realize heat recovery, and improve the overall operating efficiency of the unit. The airflow is precooled by the heat exchanger 9 on the evaporating side of the heat pipe, and the airflow is heated by the heat exchanger 10 on the condensing side of the heat pipe, so as to realize efficient heat recovery of the unit and reduce energy consumption of the barn. By designing two sets of heat pump units, the heating capacity of the drying unit can be guaranteed, the air temperature in the main air duct 4 can be rapidly increased, and the high cost caused by too many heat pump units can be avoided.

In the drying unit control method of this embodiment, when the dry bulb temperature in the drying room is less than the temperature threshold and the wet bulb temperature in the drying room is less than the low humidity threshold, the first condenser 2-2 and the second condenser 3 -2 heat up the airflow in the main air duct 4 to heat up the barn 1; when the dry bulb temperature in the barn < temperature threshold, and the low humidity threshold ≤ wet bulb temperature in the barn < high When the humidity threshold is reached, the dehumidification throttling device 8 is turned on, and the internal dehumidification circulation fan 5-4 operates, and the internal circulation air supply port 5-2 and the dehumidification are controlled according to the relationship between the dry bulb temperature of the internal dehumidification circulation fan and the dry bulb temperature of the external environment. The switch of port 5-3 and fresh air port 4-3; the air flow is dehumidified through the heat pipe evaporation side heat exchanger 9 and the internal dehumidification evaporator 7, and the air flow is dehumidified through the first condenser 2-2 and the second condenser 3-2 The airflow heats up to increase the dry bulb temperature in the barn; when the dry bulb temperature in the barn is less than the temperature threshold, and the wet bulb temperature in the barn is greater than or equal to the high humidity threshold, the dehumidification throttling device 8 is turned on, and the internal dehumidification circulation fan 5-4 operation, the internal circulation air supply port 5-2 is closed, the moisture discharge port 5-3 is opened, and the fresh air port 4-3 is opened; the dry air from the external environment is introduced through the fresh air port 4-3, and the high-humidity air in the barn is After passing through the heat exchanger 9 on the evaporating side of the heat pipe for precooling and recovering the dehumidification heat from the internal dehumidification evaporator 7, it is discharged to the external environment of the drying unit through the dehumidification port 5-3 to reduce the wet bulb temperature in the barn; The first condenser 2-2 and the second condenser 3-2 heat up the airflow in the main air duct 4 to increase the dry bulb temperature in the barn.

Therefore, the drying unit control method of this embodiment not only realizes the temperature and humidity control of the barn, but also performs heat recovery through the heat pipe heat exchanger, thereby achieving the purpose of saving energy and reducing consumption.

The drying unit control method of this embodiment makes full use of the heat recovery technology to further improve the operating efficiency of the drying unit and reduce operating costs; it solves the problem that the high-grade heat source discharged by the dehumidification process in the current drying process is not used, which leads to The problem of high energy consumption.

In this embodiment, in order to further meet the temperature and humidity requirements of the barn and save energy, when the dry bulb temperature in the barn is greater than or equal to the temperature threshold, the following step S6 is performed.

Step S6: When the dry bulb temperature in the curing room is greater than or equal to the temperature threshold, it means that the dry bulb temperature in the curing room has met the requirements. At this time, the first heat pump unit and the second heat pump unit stop running to avoid energy waste; therefore, control the first A compressor 2-1, a second compressor 3-1, a first external fan 2-5, a second external fan 3-5, a first throttling device 2-3, a second throttling device 3-3, dehumidification The throttling device 8 and the internal dehumidification circulation fan 5-3 are all closed, and the main circulation fan 4-3 is running to ensure the normal circulation of hot air in the barn; at the same time, it is also necessary to control the internal circulation air outlet, The switch of the moisture outlet and the fresh air outlet:

If the wet bulb temperature in the barn is lower than the low humidity threshold, the internal circulation air supply port, moisture exhaust port, and fresh air port are all closed, and dehumidification is not required; therefore, the control internal circulation damper, humidity exhaust damper, and fresh air damper are all closed.

If the low humidity threshold ≤ the wet bulb temperature in the drying room < the high humidity threshold, it means that the wet bulb temperature in the drying room meets the requirements, and the opening and closing status of the internal circulation air supply port, moisture discharge port and fresh air port should be maintained; therefore, the internal circulation damper should be kept , the switch status of the humidity exhaust damper and the fresh air damper.

If the wet bulb temperature in the barn is greater than or equal to the high humidity threshold, the internal circulation air supply port will be closed, the moisture discharge port will be opened, and the fresh air port will be opened for rapid dehumidification; therefore, the internal circulation damper will be controlled to close, the humidity discharge damper will be opened, and the fresh air damper will be opened .

Therefore, when the dry bulb temperature in the barn 1 is greater than or equal to the temperature threshold, the wet bulb temperature in the barn is regulated through the switches of the inner circulation air supply port, the moisture discharge port and the fresh air port, which is simple and convenient, and consumes less energy.

In this embodiment, temperature threshold=Tg0-ΔTg;

Low humidity threshold=Ts0-ΔTs; High humidity threshold=Ts0+ΔTs;

In the material drying process, each baking section has a corresponding target dry bulb temperature and target wet bulb temperature. By selecting the temperature threshold, low humidity threshold, and high humidity threshold, it is convenient to control the operation of the drying unit, so that the dry bulb temperature and wet bulb temperature in the barn meet the requirements, and avoid wasting energy.

After starting the tobacco drying process, the drying unit starts to run, and the temperature and humidity sensor 1-2 in the curing room 1 detects the dry bulb temperature Tg and the wet bulb temperature Ts in the curing room 1 in real time, and the detected dry bulb temperature The temperature Tg and wet bulb temperature Ts are sent to the controller, and the controller controls the operation of the drying unit according to the received dry bulb temperature Tg and wet bulb temperature Ts.

1. When the dry bulb temperature Tg in the oven 1 is less than Tg0-ΔTg, it means that the dry bulb temperature in the oven 1 is low at this time, and it is necessary to turn on the heat pump unit to heat up the air in the oven 1. At the same time, it is also necessary to Simultaneously detect the wet bulb temperature in the barn to determine whether dehumidification treatment is required. details as follows:

(1) When the wet bulb temperature Ts in the oven is less than Ts0-ΔTs, it means that the wet bulb temperature in the oven is low, and there is no need for dehumidification. Only need to heat up the oven 1, and the drying unit runs "outside". Endothermic mode": At this time, the controller controls the first compressor 2-1 and the second compressor 3-1 to turn on, and dynamically adjusts according to the exhaust target temperature of the first compressor 2-1 and the second compressor 3-1 The opening of the first throttling device 2-3 and the second throttling device 3-3, the first external fan 2-5, the second external fan 3-5 and the main circulation fan 4-5 run at high speed, the dehumidification throttling device 8 is in the off state, and the internal dehumidification circulation fan 5-4 is in the stop state; the internal circulation damper, the humidity exhaust damper, and the fresh air damper are all closed; The temperature of the external environment heats up the airflow in the main air duct 4 through the first condenser 2-2 and the second condenser 3-2, so as to realize heat supply and temperature rise for the barn 1 .

(2) When Ts0-ΔTs≤wet bulb temperature in the barn Ts<Ts0+ΔTs, the dry bulb temperature Tc of the wind blown by the internal dehumidification circulation fan 5-4 is detected by the internal temperature sensor 6, and the external temperature is detected by the external temperature sensor Ambient dry bulb temperature Ta, the controller compares Tc with Ta. The external temperature sensor is arranged in the external space near the fresh air outlet.

The drying unit operates in "external heat absorption + internal dehumidification and heat supply mode": the controller controls the first compressor 2-1 and the second compressor 3-1 to be turned on, the first throttling device 2-3 is turned off, and the dehumidification section The flow device 8 and the second throttling device 3-3 are opened, and the dehumidification throttling device 8 and the second throttling device 3 are dynamically adjusted according to the exhaust target temperature of the first compressor 2-1 and the second compressor 3-1 With an opening of -3, the first external fan 2-5, the second external fan 3-5 and the main circulation fan 4-5 run at high speed, and the internal dehumidification circulation fan 5-4 runs at high speed; through the heat pipe, 9 pairs of heat exchangers on the evaporation side Airflow precooling, internal dehumidification evaporator 7 recovers dehumidification heat from airflow; at this time, the heat pump unit absorbs heat from the external environment temperature through the second evaporator 3-4, recovers dehumidification heat through the heat pipe heat exchanger and internal dehumidification evaporator 7, and passes through the second evaporator 3-4 The first condenser 2-2 and the second condenser 3-2 heat up the airflow in the main air duct 4 to realize heating up and dehumidification of the barn.

At the same time, the following controls are performed on the internal circulation damper, humidity exhaust damper and fresh air damper:

(a) When Tc≥Ta, the drying unit operates in the "internal circulation dehumidification heat recovery mode", that is, the internal circulation damper is opened, the humidity exhaust damper is closed, the fresh air damper is closed, and the air blown by the internal dehumidification circulation fan 5-4 passes through the internal circulation The air supply port 5-2 and the auxiliary air return port 4-4 enter the main air duct 4.

(b) When Tc<Ta, the drying unit operates in the "external circulation fresh air heat recovery mode", that is, the internal circulation damper is closed, the humidity exhaust damper is opened, the fresh air damper is opened, and the internal dehumidification circulation fan 5-4 blows out a temperature higher than that of the external environment. The cold wind that is still low is directly discharged out of the unit through the humidity discharge port 5-3, and the outside air with a higher temperature is introduced from the fresh air port 4-3 to supplement the main air duct 4, so as to realize the overall air circulation of the barn; The control mode of low cool air and the introduction of fresh air with high temperature further realizes energy saving on the basis of heat recovery, which further reduces the overall energy consumption of the barn.

Therefore, in the process of (a) and (b) damper control, the heat pump unit adopts the "external heat absorption + internal dehumidification and heat supply mode" synchronously.

(3) When the wet bulb temperature Ts≥Ts0+ΔTs in the drying room 1, it means that the wet bulb temperature in the drying room is too high, and fast dehumidification treatment is required, that is, the drying unit operates in the "fast dehumidification mode":

The controller controls the first compressor 2-1 and the second compressor 3-1 to be turned on, the first throttling device 2-3 is in the closed state, the dehumidification throttling device 8 and the second throttling device 3-3 are turned on, according to the first The exhaust target temperatures of the first compressor 2-1 and the second compressor 3-1 dynamically adjust the opening degrees of the dehumidification throttling device 8 and the second throttling device 3-3, the first external fan 2-5, the second The external fan 3-5 and the main circulation fan 4-5 run at high speed, and the internal dehumidification circulation fan 5-4 runs at high speed.

Moreover, the controller controls the internal circulation air door to be closed, the humidity exhaust air door to be opened, and the fresh air air door to be opened to introduce dry air from the external environment through the fresh air port 4-3, and flow the high-humidity air in the barn through the heat pipe evaporation side heat exchanger 9 for pre-heating. After the dehumidification heat is recovered by the cold and internal dehumidification evaporator 7, it is discharged to the external environment of the drying unit through the dehumidification outlet 5-3.

Therefore, the "fast dehumidification mode" is: on the basis of the "external heat absorption + internal dehumidification and heating mode", then close the internal circulation damper, open the moisture exhaust damper, open the fresh air damper, perform strong dehumidification control, and quickly reach the barn internal humidity requirements.

2. When the dry bulb temperature Tg in the barn 1 ≥ Tg0-ΔTg, it means that the dry bulb temperature in the barn has reached the target requirement. At this time, the heat pump unit stops the heating operation, and the first compressor 2-1, the second Second compressor 3-1, first external fan 2-5, second external fan 3-5, first throttling device 2-3, second throttling device 3-3, dehumidification throttling device 8, internal dehumidification cycle The fans 5-4 are all closed; the main circulation fans 4-5 run at high wind speed to ensure the normal circulation of the hot air in the barn, and to perform the curing process on the tobacco leaves 1-4 inside. At the same time, it is also necessary to control the switch of the internal circulation air supply port, moisture discharge port and fresh air port according to the wet bulb temperature in the barn:

(1) When the wet-bulb temperature Ts<Ts0-ΔTs in the barn 1, close the internal circulation damper, the humidity exhaust damper and the fresh air damper.

(2) When Ts0-ΔTs≤wet bulb temperature in the barn Ts<Ts0+ΔTs, keep the internal circulation damper, humidity exhaust damper and fresh air damper in the open and close state.

(3) When the wet bulb temperature Ts in the barn 1 is greater than or equal to Ts0+ΔTs, close the internal circulation damper, and open the humidity exhaust damper and the fresh air damper.

The control method of the drying unit in this embodiment, on the basis of heat recovery, further optimizes the control scheme according to the change of the ambient temperature, and intelligently selects the actions of internal circulation dehumidification and external dehumidification to lead fresh air, so as to further improve the energy efficiency of the unit and realize the ultimate of the unit energy saving.

The inner temperature sensor 6 is arranged in the dehumidification air duct 5 and on the leeward side of the inner dehumidification evaporator 7 for detecting the dry bulb temperature in the dehumidification air duct 5 and sending the detected dry bulb temperature to the controller. An external temperature sensor is installed near the fresh air outlet 4-3 in the external space, and the external temperature sensor detects the dry bulb temperature near the fresh air outlet 4-3 in the external space, and sends the detected dry bulb temperature to the controller.

The controller controls the opening and closing of the internal circulation damper, the humidity exhaust damper and the fresh air damper according to the received dry bulb temperature sent by the inner temperature sensor 6 and the dry bulb temperature sent by the outer temperature sensor. The controller compares the dry bulb temperature sent by the internal temperature sensor 6 with the dry bulb temperature sent by the external temperature sensor (which can be realized by a voltage comparator), that is, compares the temperature in the dehumidification air duct 5 with the temperature of the external environment. When the temperature in the air duct 5 is lower than the temperature of the external environment, the controller controls the internal circulation damper to close, the humidity exhaust damper to open, and the fresh air damper to open. Air enters in the main air duct 4 through the fresh air port 4-3, which can further save energy.

By setting the internal temperature sensor 6 in the dehumidification air duct 5, it is convenient to know the dry bulb temperature in the dehumidification air duct 5, and then control the internal circulation air door and the humidity exhaust air door according to the dry bulb temperature in the dehumidification air duct 5 and the dry bulb temperature of the external environment , The opening and closing of the fresh air damper realizes energy saving and consumption reduction.

As a preferred design solution of this embodiment, the internal dehumidification circulation fan 5 - 4 is arranged between the leeward side of the internal dehumidification evaporator 7 and the internal temperature sensor 6 . The internal temperature sensor 6 detects the air temperature after passing through the heat pipe evaporation side heat exchanger 9, the internal dehumidification evaporator 7, and the internal dehumidification circulation fan 5-4, which can more accurately characterize the air temperature after cooling and dehumidification in the dehumidification air duct 5 , and then ensure accurate control of the opening and closing of the internal circulation damper, humidity exhaust damper and fresh air damper.

In this embodiment, the position of the heat pipe condensation side heat exchanger 10 is higher than the heat pipe evaporation side heat exchanger 9, that is, the heat pipe condensation side heat exchanger 10 is located above the heat pipe evaporation side heat exchanger 9; The top of 9 is connected to the top of the heat pipe condensation side heat exchanger 10 through the gas pipe joint 12, and the bottom of the heat pipe condensation side heat exchanger 10 is connected to the bottom of the heat pipe evaporation side heat exchanger 9 through the liquid pipe joint 13. Since there is a height difference between the heat exchanger 10 on the condensing side of the heat pipe and the heat exchanger 9 on the evaporating side of the heat pipe, it is convenient for the liquid refrigerant condensed from the gaseous refrigerant in the heat exchanger 10 on the condensing side of the heat pipe to quickly fall back to the heat exchanger 10 on the condensing side of the heat pipe. The entire refrigerant cycle improves the heat exchange efficiency of the heat pipe heat exchanger.

As a preferred design solution of this embodiment, the heat exchanger 9 on the evaporating side of the heat pipe and the heat exchanger 10 on the condensing side of the heat pipe are both copper tube finned heat pipe heat exchangers. Specifically, the heat exchanger 9 on the evaporating side of the heat pipe and the heat exchanger 10 on the condensing side of the heat pipe both include a liquid collector, a gas collector, and several branch pipes.

The heat exchanger 9 on the evaporating side of the heat pipe includes a liquid collecting pipe 9-1, an air collecting pipe 9-2, and several branch pipes 9-3, as shown in FIG. 5 . The liquid collecting pipe 9-1 has several liquid outlet holes for inserting the branch pipe 9-3. The gas collecting pipe 9-2 is located above the liquid collecting pipe 9-1; it has several air inlets for inserting the branch pipe 9-3. Each branch pipe 9-3 is arranged vertically, one end of each branch pipe 9-3 is inserted into the liquid collecting pipe 9-1, and the other end of each branch pipe 9-3 is inserted into the gas collecting pipe 9-2; several branch pipes 9-3 Arranged at equal intervals, the heat exchangers 9 on the evaporation side of the heat pipes exchange heat evenly. Branch pipe 9-3 is made of copper pipe. The upper outer wall of the branch pipe 9-3 is provided with fins 9-4, which are used to increase the heat exchange area with the surrounding air and improve the heat exchange efficiency.

The heat exchanger 10 on the condensation side of the heat pipe includes a liquid collecting pipe 10-1, an air collecting pipe 10-2, and several branch pipes 10-3, as shown in FIG. 6 . The liquid collecting pipe 10-1 has several liquid outlet holes for inserting the branch pipe 10-3. The gas collecting pipe 10-2 is located above the liquid collecting pipe 10-1; it has several air inlet holes for inserting the branch pipe 10-3. Each branch pipe 10-3 is arranged vertically, one end of each branch pipe 10-3 is inserted into the liquid collecting pipe 10-1, and the other end of each branch pipe 10-3 is inserted into the gas collecting pipe 10-2; several branch pipes 10-3 Arranged at equal intervals, the heat exchange of the heat exchanger 10 on the condensation side of the heat pipe is relatively uniform. The branch pipe 10-3 is made of copper pipe. The upper outer wall of the branch pipe 10-3 is provided with fins 10-4, which are used to increase the heat exchange area with the surrounding air and improve the heat exchange efficiency.

The gas collection pipe 9-2 of the heat pipe evaporation side heat exchanger 9 is connected to the gas collection pipe 10-2 of the heat pipe condensation side heat exchanger 10 through the gas pipe connecting pipe 12; the liquid collection pipe 9-1 of the heat pipe evaporation side heat exchanger 9 is connected through the liquid pipe connection pipe 13 is connected to the liquid collection pipe 10-1 of the heat exchanger 10 on the condensation side of the heat pipe.

The heat pipe condensing side heat exchanger 10 and the heat pipe evaporating side heat exchanger 9 are arranged vertically with a certain height difference. After the inside is evacuated, they are filled with refrigerant, so the heat pipe heat exchanger is a split gravity heat pipe. The refrigerant in the liquid collection pipe 9-1 of the heat pipe evaporation side heat exchanger 9 is in a liquid state, and the liquid refrigerant evaporates into a gaseous state after absorbing heat, and gradually rises along the branch pipe 9-3 until it enters the air collection pipe 9-2; the air collection pipe 9- The gaseous refrigerant in 2 enters the gas collector 10-2 of the heat pipe condensation side heat exchanger 10 through the air pipe connecting pipe 12; the external low temperature air flows through the surface of the heat pipe condensation side heat exchanger 10, and the gaseous refrigerant in the heat pipe condensation side heat exchanger 10 It is cooled and condensed into a liquid state, and flows down along the inner pipe wall of the branch pipe 10-3 until it flows to the liquid collection pipe 10-1; the liquid refrigerant in the liquid collection pipe 10-1 enters the heat pipe evaporation side heat exchanger 9 through the liquid pipe joint 13 The liquid collecting pipe 9-1 realizes refrigerant circulation.

By designing the above-mentioned heat pipe heat exchanger, not only the heat exchange is uniform and the heat exchange efficiency is high, but also the structure is simple, the cost is low, and it is easy to realize.

In this embodiment, a circulation pump is installed on the liquid pipe connection 13 to speed up the circulation speed of the refrigerant in the heat pipe heat exchanger, increase the circulation power of the refrigerant, and further improve the heat exchange efficiency of the heat pipe heat exchanger. The heat pipe heat exchanger installed with a circulating pump is a power heat pipe.

As another preferred design solution of this embodiment, the heat exchanger 9 on the evaporating side of the heat pipe and the heat exchanger 10 on the condensing side of the heat pipe are both microchannel heat pipe heat exchangers, which have high heat exchange efficiency, stable performance, and high cost performance.

In this embodiment, the internal dehumidification evaporator 7 and the heat pipe evaporation side heat exchanger 9 are arranged vertically; the top of the internal dehumidification evaporator 7 is flush with the top of the heat pipe evaporation side heat exchanger 9; The bottom is flush with the bottom of the heat pipe evaporation side heat exchanger 9, so that the airflow passing through the heat pipe evaporation side heat exchanger 9 can all pass through the internal dehumidification evaporator 7, so as to maximize the use of the internal dehumidification evaporator 7 and ensure the dehumidification effect.

In this embodiment, the internal dehumidification evaporator 7 and the heat pipe evaporation side heat exchanger 9 are arranged vertically, and the internal dehumidification evaporator 7 is in contact with the leeward surface of the heat pipe evaporation side heat exchanger 9, which can reduce space occupation. A water receiving pan 11 is provided at the bottom of the inner dehumidification evaporator 7 and the heat pipe evaporation side heat exchanger 9 for receiving the condensed water flowing down from the inner dehumidifying evaporator 7, and the condensed water flowing into the water receiving pan 11 is drained The pipe discharges to the outside of the unit.

The drying unit control method and drying system of this embodiment can fully recover and apply the high-temperature and high-humidity high-grade heat source in the dehumidification process in the drying process, further improve the operating efficiency of the drying unit, and improve the efficiency of the drying unit. Energy efficiency, to achieve the purpose of energy saving and emission reduction.

Of course, the above descriptions are not intended to limit the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention shall also belong to protection scope of the present invention.

Claims

A drying unit control method, characterized in that: comprising:

A first heat pump unit, which includes a first compressor, a first condenser, a first throttling device, and a first evaporator;

The second heat pump unit includes a second compressor, a second condenser, a second throttling device, and a second evaporator;

The main air duct has a fresh air outlet, and a main circulation fan is arranged in it;

The dehumidification air duct has an internal circulation air supply port connected to the main air duct and a moisture discharge port connected to the external space; the dehumidification air duct is provided with an internal dehumidification circulation fan, an internal dehumidification evaporator, and a heat pipe evaporation side heat exchanger; A dehumidification throttling device is arranged on the connecting pipeline between the internal dehumidification evaporator and the first condenser;

The control methods include:

Obtain the dry bulb temperature in the barn, and when the dry bulb temperature is less than the temperature threshold, perform the following operations:

If the wet bulb temperature in the barn is lower than the low humidity threshold, the first compressor and the second compressor are controlled to start, the first throttling device and the second throttling device are turned on, the dehumidification throttling device is turned off, and the internal dehumidification circulating fan is turned off. The main circulation fan is running; the internal circulation air supply outlet, humidity exhaust outlet and fresh air outlet are all closed;

If the low humidity threshold ≤ the wet bulb temperature in the barn < the high humidity threshold, the first compressor and the second compressor are controlled to start, the first throttling device is closed, the second throttling device and the dehumidification throttling device are turned on, and the internal dehumidification Circulation fan and main circulation fan are running; according to the relationship between the dry bulb temperature of the air outlet of the internal dehumidification circulation fan and the dry bulb temperature of the external environment, the switches of the internal circulation air supply port, moisture discharge port and fresh air port are controlled;

If the wet bulb temperature in the barn is greater than or equal to the high humidity threshold, control the first compressor and the second compressor to start, the first throttling device to close, the second throttling device, the dehumidification throttling device to open, the internal dehumidification circulation fan, the main The circulation fan is running; the internal circulation air supply port is closed, the moisture exhaust port is opened, and the fresh air port is opened.
The drying unit control method according to claim 1, characterized in that: according to the relationship between the dry bulb temperature of the air outlet of the internal dehumidification circulating fan and the dry bulb temperature of the external environment, the internal circulation air supply port, the humidity discharge port, and the fresh air port are controlled switches, including:

If Tc≥Ta, the internal circulation air supply port is opened, the moisture discharge port is closed, and the fresh air port is closed;

If Tc<Ta, the internal circulation air supply port is closed, the moisture discharge port is opened, and the fresh air port is opened;

Among them, Tc is the dry bulb temperature of the internal dehumidification circulating fan; Ta is the dry bulb temperature of the external environment.
The drying unit control method according to claim 1, characterized in that: when the dry bulb temperature in the drying room is greater than or equal to the temperature threshold, the following operations are performed:

Control the first compressor, the second compressor, the first throttling device, the second throttling device, the dehumidification throttling device, and the internal dehumidification circulation fan to be closed, and the main circulation fan is running;

When the wet bulb temperature in the barn is lower than the low humidity threshold, the internal circulation air supply port, moisture discharge port and fresh air port are all closed;

When the low humidity threshold ≤ the wet bulb temperature in the barn < the high humidity threshold, keep the internal circulation air supply port, moisture discharge port and fresh air port on and off;

When the wet bulb temperature in the barn is greater than or equal to the high humidity threshold, the internal circulation air supply port is closed, the moisture discharge port is opened, and the fresh air port is opened.
The drying unit control method according to claim 1, characterized in that:

Temperature threshold = Tg0-ΔTg;

Low humidity threshold = Ts0-ΔTs;

High humidity threshold = Ts0 + ΔTs;

Among them, Tg0 is the target dry bulb temperature; ΔTg is the hysteresis of the target dry bulb control accuracy;

Ts0 is the target wet bulb temperature; ΔTs is the hysteresis of the target wet bulb control accuracy.
The drying unit control method according to claim 1, characterized in that: the windward side of the first evaporator is provided with a heat pipe condensation side heat exchanger, and the position of the heat pipe condensation side heat exchanger is higher than that of the heat pipe Evaporating side heat exchanger; the top of the heat pipe evaporating side heat exchanger is connected to the top of the heat pipe condensing side heat exchanger through a gas pipe joint, and the bottom of the heat pipe condensing side heat exchanger is connected to the heat pipe evaporating side through a liquid pipe joint. bottom of side heat exchanger.
The drying unit control method according to claim 5, characterized in that: the heat exchanger on the condensing side of the heat pipe and the heat exchanger on the evaporating side of the heat pipe both include a liquid collection pipe, a gas collection pipe, and several branch pipes;

The air collecting pipe is located above the liquid collecting pipe; each of the branch pipes is arranged vertically, one end of each of the branch pipes is inserted into the liquid collecting pipe, and the other end of each of the branch pipes is inserted into the air collecting pipe ; Several branch pipes are arranged at equal intervals; the upper outer wall of the branch pipe is provided with fins;

The air collector of the heat pipe evaporation side heat exchanger is connected to the air collector of the heat pipe condensation side heat exchanger through the air pipe joint;

The liquid collecting pipe of the heat exchanger on the evaporating side of the heat pipe is connected to the liquid collecting pipe of the heat exchanger on the condensing side of the heat pipe through the connecting pipe of the liquid pipe.
The drying unit control method according to claim 5, characterized in that: a circulation pump is arranged on the connecting pipe of the liquid pipe.
The drying unit control method according to claim 5, wherein the heat exchanger on the condensation side of the heat pipe and the heat exchanger on the evaporation side of the heat pipe are both micro-channel heat pipe heat exchangers.
The drying unit control method according to claim 1, characterized in that: the internal dehumidification evaporator and the heat pipe evaporation side heat exchanger are arranged vertically, and the top of the internal dehumidification evaporator is connected to the heat pipe evaporation side heat exchanger The top of the internal dehumidification evaporator is flush with the bottom of the heat pipe evaporation side heat exchanger; the internal dehumidification evaporator is in contact with the leeward surface of the heat pipe evaporation side heat exchanger.
A drying system, characterized in that: comprising:

The barn is equipped with a temperature and humidity sensor for collecting the dry bulb temperature and wet bulb temperature in the barn;

Drying unit, the controller of which executes the control method according to any one of claims 1-9.