A water-cooled deep dehumidification air conditioner and its control method

Abstract

The present invention discloses a water-cooled deep dehumidification air conditioner and a control method thereof. The water-cooled deep dehumidification air conditioner includes an air intake section, a filtration section, a first-stage refrigeration section, a second-stage refrigeration section, a condensation reheat section, an electric heating section, a humidification section, and a blower section, which are connected in sequence along an air path. The first-stage refrigeration section, the second-stage refrigeration section, and the condensation reheat section each include an independent refrigeration system, and the water system includes a first water valve, a second water valve, and a third water valve. Each water-cooled heat exchanger is connected to each water valve and connected in parallel to the water system. The control method of the water-cooled deep dehumidification air conditioner provided by the present invention determines the number of dehumidification startup stages by comparing the moisture content of the supply air with the set moisture content, and adjusts the cooling capacity by adjusting the frequency of the third-stage compressor. This method compensates for the limitations of traditional air-cooled air conditioners and improves the dehumidification capacity and accuracy of the air conditioner. The control logic is optimized to make the air conditioner more adaptable and have a higher fault tolerance, thereby ensuring the long-term and stable operation of the dehumidification air conditioner.

Description

Technical Field

[0001] The present invention relates to a water-cooled deep dehumidification air conditioner and also to a control method of the water-cooled deep dehumidification air conditioner, belonging to the technical field of air conditioning. Background Art

[0002] Certain locations with high humidity requirements, such as underground projects, often experience low temperatures and high humidity (e.g., the large enthalpy difference between the inside and outside of caverns in summer). Conventional air conditioners struggle to lower the dew point of the air (including return and fresh air) to a level that prevents condensation. Consequently, the dehumidification capacity of traditional air-cooled air conditioners often falls short. These locations not only require low humidity levels, but are also limited by installation space and location (for example, underground projects lack the conditions for installing air-cooled outdoor units). This makes it difficult to ensure normal equipment operation, proper storage of items, and a comfortable environment for personnel.

[0003] Chinese patent application number 202510055881.5 discloses a system and method for independent mine heat and humidity control. This technical solution includes a ventilation system that sequentially directs mine airflow through a dust removal system, a dehumidification system, and a cooling system to produce clean, low-temperature, and low-humidity air. A heat recovery system collects waste heat from the cooling system, dehumidification system, dust removal system, and mine water collection device. A power system provides circulating power for the water circulation in the cooling system, dehumidification system, mine water collection device, and dust removal system, maintaining stable system operation. An intelligent control system monitors the operating parameters of the cooling system, dehumidification system, dust removal system, heat recovery system, and ventilation system, as well as mine parameters, enabling adjustable air supply parameters, operating parameters, and backup equipment. Safety warnings are also provided through a central controller. This system and method independently regulate temperature and humidity, fully utilize waste heat, and maintain low system energy consumption.

[0004] Traditional air-cooled air conditioners have limitations in dehumidification, with limited dehumidification efficiency, making them difficult to meet the demands of rapid dehumidification in high-humidity environments. While existing water-cooled air conditioners offer certain advantages in cooling, their deep dehumidification capabilities still need improvement. For one thing, some systems lack sufficient dehumidification precision, making it difficult to meet demanding humidity requirements. Furthermore, existing control systems lack a high level of intelligence, failing to accurately adjust operating parameters in real time based on changes in ambient humidity, resulting in unstable dehumidification. Therefore, developing a water-cooled air conditioner capable of deep dehumidification, high energy efficiency, and intelligent control is of great practical significance. Summary of the Invention

[0005] The primary technical problem to be solved by the present invention is to provide a water-cooled deep dehumidification air conditioner.

[0006] Another technical problem to be solved by the present invention is to provide a control method for the above-mentioned water-cooled deep dehumidification air conditioner.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0008] According to a first aspect of an embodiment of the present invention, a water-cooled deep dehumidification air conditioner is provided, comprising an air intake section, a filtration section, a first-stage refrigeration section, a second-stage refrigeration section, a condensation reheat section, an electric heating section, a humidification section, a blower section, and a water system, wherein:

[0009] The air inlet section, the filtration section, the first-stage refrigeration section, the second-stage refrigeration section, the condensation and reheating section, the electric heating section, the humidification section and the blower section are sequentially connected along the air path;

[0010] The first-stage refrigeration section, the second-stage refrigeration section and the condensing and reheating section all include independent refrigeration systems;

[0011] The water system includes a controller, a first water valve, a second water valve, a third water valve, a first temperature sensor, a second temperature sensor and a third temperature sensor; the water system is connected to the first-stage refrigeration section through the first water valve, and the first temperature sensor obtains the inlet and outlet water temperatures of the first-stage refrigeration section; the water system is connected to the second-stage refrigeration section through the second water valve, and the second temperature sensor obtains the inlet and outlet water temperatures of the second-stage refrigeration section; the water system is connected to the condensing reheat section through the third water valve, and the third temperature sensor obtains the inlet and outlet water temperatures of the condensing reheat section.

[0012] Preferably, the air inlet section is an air inlet device, including an air inlet section temperature sensor and an air inlet section relative humidity sensor, for introducing external air and measuring the air inlet temperature and air inlet relative humidity;

[0013] The filtering section is an air filtering device; the electric heating section is an air heating device; the humidifying section is an air humidifying device;

[0014] The blower section is an air supply device, including an air supply fan, an air supply section temperature sensor and an air supply section relative humidity sensor, which are used to supply air and measure the supply air temperature and the supply air relative humidity.

[0015] Preferably, the first stage refrigeration section includes a first compressor unit, a first water-cooled heat exchanger, a first liquid storage tank, a first evaporator and a first gas-liquid separator; wherein,

[0016] The outlet of the first compressor unit is connected to the refrigerant pipeline inlet of the first water-cooled heat exchanger, the refrigerant pipeline outlet of the first water-cooled heat exchanger is connected to the inlet of the first liquid storage tank, the outlet of the first liquid storage tank is connected to the inlet of the first evaporator, the outlet of the first evaporator is connected to the inlet of the first gas-liquid separator, and the outlet of the first gas-liquid separator is connected to the inlet of the first compressor unit;

[0017] The first water valve is connected to the heat exchange medium pipeline of the first water-cooled heat exchanger.

[0018] Preferably, the second stage refrigeration section includes a second compressor unit, a second water-cooled heat exchanger, a second liquid storage tank, a second evaporator and a second gas-liquid separator; wherein,

[0019] The outlet of the second compressor unit is connected to the refrigerant pipeline inlet of the second water-cooled heat exchanger, the refrigerant pipeline outlet of the second water-cooled heat exchanger is connected to the inlet of the second liquid storage tank, the outlet of the second liquid storage tank is connected to the inlet of the second evaporator, the outlet of the second evaporator is connected to the inlet of the second gas-liquid separator, and the outlet of the second gas-liquid separator is connected to the inlet of the second compressor unit;

[0020] The second water valve is connected to the heat exchange medium pipeline of the second water-cooled heat exchanger.

[0021] Preferably, the second compressor unit includes a plurality of fixed-frequency compressors.

[0022] Preferably, the condensation and reheating section includes a third compressor unit, a third water-cooled heat exchanger, a third liquid storage tank, a third evaporator, a third gas-liquid separator and a reheater; wherein,

[0023] The outlet of the third compressor group is connected to the refrigerant pipeline inlet of the third water-cooled heat exchanger, the refrigerant pipeline outlet of the third water-cooled heat exchanger is connected to the inlet of the third liquid storage tank, the outlet of the third liquid storage tank is connected to the inlet of the third evaporator, the outlet of the third evaporator is connected to the inlet of the third gas-liquid separator, and the outlet of the third gas-liquid separator is connected to the inlet of the third compressor group;

[0024] The inlet of the reheater is connected to the outlet of the third compressor unit, and the outlet of the reheater is connected to the inlet of the third evaporator; the reheater is arranged in the downstream direction of the third evaporator;

[0025] The third water valve is connected to the heat exchange medium pipeline of the third water-cooled heat exchanger.

[0026] Preferably, the third compressor unit includes one or more variable frequency compressors.

[0027] According to a second aspect of an embodiment of the present invention, there is provided a method for controlling the water-cooled deep dehumidification air conditioner, comprising the following steps:

[0028] Step S1: Start the air supply fan to the preset fan power, and the controller collects and calculates in real time the target moisture content dob, the inlet air moisture content den, the supply air moisture content dex, the target air temperature tob, the inlet air temperature ten, the supply air temperature tex, the target temperature difference ΔTob, the inlet water temperature Ten, the outlet water temperature Tex, and the inlet and outlet water temperature difference ΔTwa of each cooling section; and when it is determined that den is less than dob and ten is less than tob, go to step S7; when den is equal to dob and ten is equal to tob, repeat step S1; otherwise, go to step S2;

[0029] Step S2: When dob<den≤d1, start the third compressor unit to the initial frequency and open the third water valve; when d1<den≤d2, start the third compressor unit to the initial frequency, start one compressor of the second compressor unit, and open the second water valve and the third water valve; when d2<den≤d3, start the third compressor unit to the initial frequency, start all compressors of the second compressor unit, and open the second water valve and the third water valve; when d3<den, start the third compressor unit to the initial frequency, start all compressors of the second compressor unit, start the first compressor unit, and open the first water valve, the second water valve, and the third water valve;

[0030] When opening each water valve, if Ten≤T1 of the cooling section where the water valve is located, the initial opening of the water valve is OP1; if T1<Ten≤T2, the initial opening of the water valve is OP2; if T2<Ten≤T3, the initial opening of the water valve is OP3; if T3<Ten, the initial opening of the water valve is OP4;

[0031] Step S3: Based on the moisture content read and calculated in real time, when dex=dob, the operating frequency of the third compressor unit is maintained unchanged; when dex<dob, the operating frequency of the third compressor unit is reduced according to the humidification design value; when dob<dex, the operating frequency of the third compressor unit is increased according to the dehumidification design value;

[0032] Step S4: obtaining the high pressure HP in real time; when P1 < HP < P2, maintaining the opening of the third water valve unchanged; when P2 ≤ HP, increasing the opening of the third water valve according to the flow increase design value to increase the water flow, thereby increasing the heat exchange; when HP ≤ P1, decreasing the opening of the third water valve according to the flow reduction design value to reduce the water flow, thereby reducing the heat exchange;

[0033] Step S5: Obtain the opening of the reheat expansion valve OPex in real time; when tex = tob, maintain the opening of the reheat expansion valve unchanged; when tex < tob, increase the opening of the reheat expansion valve according to the temperature increase design value; when tob < tex, reduce the opening of the reheat expansion valve according to the temperature decrease design value; when OPex ≤ OP5, close the reheat valve; when OP5 < OPex, open the reheat valve;

[0034] Step S6: For the first refrigeration section and / or the second refrigeration section that has been turned on, when ΔTwa=ΔTob of the refrigeration section, the opening of the first water valve and / or the second water valve is maintained unchanged; when ΔTwa<ΔTob, the opening of the first water valve and / or the second water valve is reduced according to the design value of the temperature increase difference, thereby reducing the flow rate through the water valve; when ΔTob<ΔTwa, the opening of the first water valve and / or the second water valve is increased according to the design value of the temperature reduction difference, thereby increasing the flow rate through the water valve;

[0035] The unopened refrigeration sections remain unchanged;

[0036] Step S7: When tex<tob, turn on the electric heating section to the required power; when dex<dob, turn on the humidification section to the required humidification amount; go to step S1.

[0037] Preferably, step S1 includes the following sub-steps:

[0038] Sub-step S11: starting the air supply fan 81 to a preset fan power;

[0039] Sub-step S12: The controller collects and calculates in real time the target moisture content dob, the inlet air moisture content den, the supply air moisture content dex, the target air temperature tob, the inlet air temperature ten, the supply air temperature tex, the target temperature difference ΔTob, the inlet water temperature Ten, the outlet water temperature Tex, and the inlet and outlet water temperature difference ΔTwa of each cooling section;

[0040] Sub-step S13: Compare den with dob, ten with tob; when den < dob, and ten < tob, go to step S7; when den = dob, and ten = tob, go to sub-step S12; otherwise, go to step S2.

[0041] Preferably, step S7 includes the following sub-steps:

[0042] Sub-step S71: When tex<tob and the reheat expansion valve reaches the maximum opening, proceed to sub-step S72; when tex<tob and the third compressor unit is not turned on, proceed to sub-step S72; otherwise, proceed to sub-step S73;

[0043] Sub-step S72: turning on the electric heating section to the required power;

[0044] Sub-step S73: When dex<dob, and the third compressor unit is not turned on, the humidification section is turned on to the required humidification amount; go to step S1.

[0045] This invention overcomes the limitations of traditional air-cooled air conditioners and improves the dehumidification capacity and accuracy of the air conditioner. The internal control logic is optimized, making the air conditioner more adaptable and more fault-tolerant, ensuring long-term and stable operation of the dehumidifying air conditioner. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a schematic structural diagram of a water-cooled deep dehumidification air conditioner in the first embodiment of the present invention;

[0047] Figure 2 for Figure 1 Schematic diagram of the structure of the first stage refrigeration section;

[0048] Figure 3 for Figure 1 Schematic diagram of the structure of the second stage refrigeration section;

[0049] Figure 4 for Figure 1 Structural diagram of the condensation and reheating section;

[0050] Figure 5 This is a schematic structural diagram of a water system in the first embodiment of the present invention;

[0051] Figure 6 This is a schematic diagram of the steps of a method for adjusting a water-cooled deep dehumidification air conditioner in a second embodiment of the present invention;

[0052] Figure 7 for Figure 6 Schematic diagram of sub-steps of step S1 in FIG. DETAILED DESCRIPTION

[0053] The technical content of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] The technical concept behind the embodiments of the present invention is to use a plate heat exchanger and a water system as the cooling source for the air conditioner's outdoor unit, exchanging heat between the air conditioner's refrigerant and the outdoor unit, with the water system transferring the heat to the outside. Specifically, the condenser in each cooling stage is a water-cooled heat exchanger (e.g., a plate heat exchanger) that exchanges heat with the water system. Dehumidification is achieved through condensation, which condenses moisture by lowering the air temperature, rather than directly using cold water. The moisture content of the incoming air temperature determines which cooling stage to activate, achieving deep dehumidification.

[0055] First embodiment

[0056] like Figure 1 As shown, an embodiment of the present invention provides a water-cooled deep dehumidification air conditioner, comprising an air intake section 1, a filtration section 2, a first-stage refrigeration section 3, a second-stage refrigeration section 4, a condensation and reheat section 5, an electric heating section 6, a humidification section 7, a blower section 8, and a water system 9. The air intake section 1, the filtration section 2, the first-stage refrigeration section 3, the second-stage refrigeration section 4, the condensation and reheat section 5, the electric heating section 6, the humidification section 7, and the blower section 8 are sequentially connected along an air path.

[0057] The air inlet section 1 is the air inlet section of the water-cooled deep dehumidification air conditioner and includes an air duct, an air inlet temperature sensor 11, and an air inlet relative humidity sensor 12. It is used to draw in outside air and measure the inlet air temperature (ten) and relative humidity (φen). The filtration section 2 is the air filtration section of the water-cooled deep dehumidification air conditioner and is used to remove large particles from the outside air. The first-stage refrigeration section 3, the second-stage refrigeration section 4, and the condenser reheat section 5 are collectively referred to as the refrigeration section and each comprises an independent refrigeration system. Each refrigeration section adopts a modular design and is independent of each other. The electric heating section 6 is an air heating device used to heat the airflow within the water-cooled deep dehumidification air conditioner. The humidification section 7 is an air humidification device used to increase the moisture content of the airflow. The blower section 8 is the air supply section and includes an air duct, a blower 81, a blower temperature sensor 82, and a blower relative humidity sensor 83. It provides flow dynamics for the airflow and measures the supply air temperature (tex) and relative humidity (φex).

[0058] like Figure 2 As shown, the first-stage refrigeration section 3 includes a first compressor unit 31, a first water-cooled heat exchanger 32, a first liquid storage tank 33, a first evaporator 34, and a first gas-liquid separator 35. The outlet of the first compressor unit 31 is connected to the refrigerant pipeline inlet of the first water-cooled heat exchanger 32, the refrigerant pipeline outlet of the first water-cooled heat exchanger 32 is connected to the inlet of the first liquid storage tank 33, the outlet of the first liquid storage tank 33 is connected to the inlet of the first evaporator 34, the outlet of the first evaporator 34 is connected to the inlet of the first gas-liquid separator 35, and the outlet of the first gas-liquid separator 35 is connected to the inlet of the first compressor unit 31. It is worth noting that the first compressor unit 31 is a fixed-frequency compressor.

[0059] After being pressurized and heated by the first compressor unit 31, the refrigerant is fed into the refrigerant pipeline of the first water-cooled heat exchanger 32. The first water-cooled heat exchanger 32 includes two independent pipelines (a heat exchange medium pipeline and a refrigerant pipeline) for achieving heat exchange between the fluids in the two pipelines. The heat exchange medium pipeline (the heat exchange medium in this embodiment is water) of the first water-cooled heat exchanger 32 is connected to the water supply pipeline of the water system 9 to reduce the refrigerant temperature. The cooled refrigerant is fed into the first liquid storage tank 33 along the refrigerant pipeline for storage. According to system needs, it is fed into the first evaporator 34 for evaporation and heat absorption to reduce the air flow temperature in the first-stage refrigeration section 3. The refrigerant that has absorbed heat and heated up is fed into the first gas-liquid separator 35, and the gaseous refrigerant therein is fed into the first compressor unit 31 to continue circulating.

[0060] like Figure 3As shown, similarly, the second-stage refrigeration section 4 includes a second compressor unit 41, a second water-cooled heat exchanger 42, a second liquid storage tank 43, a second evaporator 44, and a second gas-liquid separator 45. The outlet of the second compressor unit 41 is connected to the refrigerant pipeline inlet of the second water-cooled heat exchanger 42, the refrigerant pipeline outlet of the second water-cooled heat exchanger 42 is connected to the inlet of the second liquid storage tank 43, the outlet of the second liquid storage tank 43 is connected to the inlet of the second evaporator 44, the outlet of the second evaporator 44 is connected to the inlet of the second gas-liquid separator 45, and the outlet of the second gas-liquid separator 45 is connected to the inlet of the second compressor unit 41. It is worth noting that the second compressor unit 41 includes multiple fixed-frequency compressors, for example, two fixed-frequency compressors, and each compressor operates in parallel.

[0061] The second water-cooled heat exchanger 42 includes two independent pipelines (a heat exchange medium pipeline and a refrigerant pipeline) for heat exchange between the fluids within the two pipelines. The heat exchange medium pipeline (water in this embodiment) of the second water-cooled heat exchanger 42 is connected to the water supply pipeline of the water system 9. The refrigerant in the refrigerant pipeline and the operating principle are the same as those in the first-stage refrigeration section 3 and will not be further described.

[0062] like Figure 4 As shown, the condensing and reheating section 5 includes a third compressor unit 51, a third water-cooled heat exchanger 52, a third liquid storage tank 53, a third evaporator 54, a third gas-liquid separator 55, and a reheater 56. The outlet of the third compressor unit 51 is connected to the refrigerant pipeline inlet of the third water-cooled heat exchanger 52, the refrigerant pipeline outlet of the third water-cooled heat exchanger 52 is connected to the inlet of the third liquid storage tank 53, the outlet of the third liquid storage tank 53 is connected to the inlet of the third evaporator 54, the outlet of the third evaporator 54 is connected to the inlet of the third gas-liquid separator 55, and the outlet of the third gas-liquid separator 55 is connected to the inlet of the third compressor unit 51. The inlet of the reheater 56 is connected to the outlet of the third compressor unit 51, and the outlet is connected to the inlet of the third evaporator 54. The reheater 56 is located downstream of the third evaporator 54 along the air path, and the third evaporator 54 is located upstream of the reheater 56. It is worth noting that the third compressor unit 51 includes one or more variable frequency compressors.

[0063] Preferably, the condensing reheat section 5 further includes a reheat valve 57, a reheat expansion valve 58, and a pressure sensor 59. The reheat valve 57 is disposed between the inlet of the third water-cooled heat exchanger 52 and the reheater 56, and can open or close the connection between the outlet of the third compressor unit 51 and the inlet of the reheater 56. Opening the reheat valve 57 activates the reheater 56, allowing high-temperature refrigerant from the third compressor unit 51 to flow through it, heating the airflow in the condensing reheat section 5. Closing the reheat valve 57 shuts down the reheater 56, deactivating its heating capacity. The reheat valve 57 is a switching on / off valve.

[0064] The reheat expansion valve 58 is disposed between the outlet of the reheater 56 and the inlet of the third evaporator 54 and is capable of regulating or blocking the flow between the outlet of the reheater 56 and the inlet of the evaporator 54. The reheat expansion valve 58 is an electronic expansion valve.

[0065] The pressure sensor 59 is provided on the output pipeline of the third compressor unit 51 and is connected to the controller 90 of the water system 9 for measuring the pressure of the outlet pipeline of the third compressor unit 51. The controller 90 can control the opening of the reheat valve 57 based on the measured value of the pressure sensor 59.

[0066] The heat exchange medium pipeline of the third water-cooled heat exchanger 52 is connected to the water supply pipeline of the water system 9 .

[0067] like Figure 5 As shown, the water system 9 includes a controller 90, water supply pipelines, water supply equipment, a first water valve 91, a second water valve 92, a third water valve 93, a first temperature sensor 911, a second temperature sensor 921, and a third temperature sensor 931. The first water valve 91, the second water valve 92, and the third water valve 93 are collectively referred to as water valves. The first water valve 91 of the water system 9 connects to the heat exchange medium pipeline of the first water-cooled heat exchanger 32, the second water valve 92 connects to the heat exchange medium pipeline of the second water-cooled heat exchanger 42, and the third water valve 93 connects to the heat exchange medium pipeline of the third water-cooled heat exchanger 52. In other words, each refrigeration stage is connected to the water system 9 via a water valve, and the water system 9 is connected in parallel. The water valves connecting each refrigeration stage in the water system 9 are also referred to as the water valves of that refrigeration stage. For example, the first water valve 91 is also referred to as the water valve of the first-stage refrigeration stage 3. The water system 9 is bidirectionally connected to each refrigeration stage, supplying water to each refrigeration stage and receiving return water from each refrigeration stage.

[0068] The first temperature sensor 911 is provided on the first water valve 91 to obtain the water inlet temperature Ten and water outlet temperature Tex of the first refrigeration section 3 (first water-cooled heat exchanger 32). The controller 90 calculates the inlet and outlet water temperature difference ΔTwa of the first water valve 91, ΔTwa = Tex - Ten.

[0069] The second temperature sensor 921 is provided on the second water valve 92 to obtain the water inlet temperature Ten and water outlet temperature Tex of the second refrigeration section 4 (the second water-cooled heat exchanger 42). The controller 90 calculates the inlet and outlet water temperature difference ΔTwa of the second water valve 92, ΔTwa = Tex - Ten.

[0070] The third temperature sensor 931 is installed on the third water valve 93 to obtain the inlet and outlet water temperatures Ten and Tex of the condensing reheat section 5 (the third water-cooled heat exchanger 52). The controller 90 calculates the inlet and outlet water temperature difference ΔTwa of the third water valve 93, where ΔTwa = Tex - Ten.

[0071] Since each refrigeration section exchanges the refrigerant heat to the water system 9 through the water-cooled heat exchanger, ΔTwa is a positive value.

[0072] It is worth noting that in the water-cooled deep dehumidification air conditioner provided in this embodiment, turning on the third compressor unit 51 necessarily opens the third water valve 93. Turning on the second compressor unit 41 necessarily opens the second water valve 92. Turning on the first compressor unit 31 necessarily opens the first water valve 91. Conversely, for a compressor unit that is not turned on, the corresponding water valve will not be turned on either. Turning on a compressor unit means turning on the refrigeration section where the compressor unit is located. In other words, turning on a certain refrigeration section means turning on the compressor unit and water valve included in the refrigeration section, and turning on a certain compressor unit means turning on the refrigeration section.

[0073] Second embodiment

[0074] A second embodiment of the present invention provides a control method for a water-cooled deep dehumidification air conditioner, which controls the start / stop relationship of each refrigeration section and the opening degree of each water valve based on the moisture content of the inlet air of the water-cooled deep dehumidification air conditioner.

[0075] Whether dehumidification is needed and the intensity of dehumidification are determined by moisture content. Moisture content refers to the weight of water vapor in 1 kg of dry air in moist air, which is often expressed by d, with the unit of g / kg. Enthalpy is a unit of energy that represents the combined amount of water and temperature in a certain volume of air. It is a comprehensive measure of air humidity and humidity. Its value is completely determined by temperature and humidity. Its calculation formula is as follows:

[0076] Moisture content calculation formula

[0077] d=0.622Фps / (B-Фps) (1)

[0078] Calculation formula for water vapor saturation partial pressure

[0079] (2)

[0080] The moisture content d can be calculated from the relative humidity φ, the local atmospheric pressure B, and the saturated partial pressure of water vapor ps. The saturated partial pressure of water vapor ps can be calculated from the temperature t and related constants. However, as a state function, the moisture content d is independent of the temperature t. On the psychrometric diagram, the moisture content corresponds one-to-one with the thermodynamic state of the air, making it suitable as a feedback variable in control systems. In the field of dehumidification air conditioning, the moisture content is a reliable control benchmark due to its temperature independence and direct mathematical relationship with the dehumidification capacity.

[0081] The comfortable humidity range d is: ① In summer, 5-12 g / kg, corresponding to temperatures of 24-28°C and relative humidity of 40%-60%; ② In winter, 3-6 g / kg, corresponding to temperatures of 18-22°C and relative humidity of 30%-50%. In high temperatures, a lower humidity content (e.g., 8 g / kg) is more comfortable. In hot and humid areas (such as mines and tunnels), the humidity content should be controlled below 12 g / kg.

[0082] Therefore, the control method provided by the embodiments of the present invention uses the inlet air humidity content den, the target humidity content dob, the supply air humidity content dex, the first humidity content d1, the second humidity content d2, and the third humidity content d3 as control benchmarks. Inlet air humidity content den is the humidity content of the air entering inlet section 1, calculated by the controller 90 of the water system 9 based on the inlet air temperature ten and the relative humidity φen of the air entering inlet section 1. Target humidity content dob ​​is the manually set (expected) humidity content of the supply air from blower section 8. Supply air humidity content dex is the humidity content of the air entering inlet section 8, calculated by the controller 90 of the water system 9 based on the supply air temperature tex and the relative humidity φex of the air entering inlet section 8. The first humidity content d1, the second humidity content d2, and the third humidity content d3 are manually set benchmark values.

[0083] In one embodiment of the present invention, dob < d1 < d2 < d3. Optionally, dob is 3-12 g / kg, d1 is 10-14 g / kg, d2 is 16-20 g / kg, and d3 is 23-27 g / kg. Preferably, d1 is 12 g / kg, d2 is 18 g / kg, and d3 is 25 g / kg.

[0084] Preferably, the embodiment of the present invention uses the inlet air temperature ten, the target air temperature tob, the supply air temperature tex, the inlet water temperature Ten of each refrigeration section, the outlet water temperature Tex of each refrigeration section, the inlet and outlet water temperature difference ΔTwa of each refrigeration section, the target temperature difference ΔTob, the first water temperature T1, the second water temperature T2, and the third water temperature T3 as control benchmarks. The inlet air temperature ten is the air temperature of the air entering the air inlet section 1, obtained by the inlet air section temperature sensor 11. The target air temperature tob is the manually set (expected) supply air temperature of the blower section 8. The supply air temperature tex is the temperature of the air supplied by the blower section 8, obtained by the blower section temperature sensor 82. The inlet water temperature Ten of each refrigeration section is the water temperature entering the water-cooled heat exchanger of each refrigeration section input by the water system 9, obtained by the temperature sensors of the water system 9. The outlet water temperature Tex of each refrigeration section is the water temperature exiting the water-cooled heat exchanger of each refrigeration section output by the water system 9, obtained by the temperature sensors of the water system 9. The inlet and outlet water temperature difference ΔTwa = Tex - Ten for each cooling section (water-cooled heat exchanger) is calculated by the controller 90 of the water system 9. The target temperature difference ΔTob is the manually set (expected) inlet and outlet water temperature difference. The first water temperature T1, the second water temperature T2, and the third water temperature T3 are manually set reference values ​​for the inlet water temperature.

[0085] In one embodiment of the present invention, T1 < T2 < T3. Optionally, T1 is 10-20°C, T2 is 20-30°C, and T3 is 30-40°C. Preferably, T1 is 15°C, T2 is 25°C, and T3 is 35°C.

[0086] Optionally, ΔTob is 1 to 9° C. Preferably, ΔTob is 5° C.

[0087] It's worth noting that the water-cooled deep dehumidification air conditioners provided by the embodiments of the present invention operate in a specialized environment requiring low air volume and deep dehumidification. This can easily lead to icing on the evaporator due to insufficient air flow, which can prevent the evaporator from releasing heat in a timely manner. The control method provided by the embodiments of the present invention, which controls the inlet and outlet water temperature differential to 5°C, can maintain a high degree of subcooling (10-15°C) of the refrigerant after the plate heat exchanger. This improves the stability of the air conditioning system in low-temperature environments and reduces the risk of evaporator frosting.

[0088] Preferably, the embodiment of the present invention uses high pressure HP, first pressure P1, and second pressure P2 as control references. High pressure HP is the outlet pipeline pressure of the third compressor unit 51, obtained by pressure sensor 59. First pressure P1 and second pressure P2 are manually set high pressure reference values. P1 < P2. Optionally, P1 is 1-2 MPa, and P2 is 2-3 MPa. Preferably, P1 is 1.5 MPa, and P2 is 2.2 MPa.

[0089] Preferably, the embodiment of the present invention uses the expansion valve opening OPex as a control reference to control the opening and closing of the reheat valve 57. OPex represents the opening of the reheat expansion valve 58 and is controlled by the inlet air temperature ten and the supply air temperature tex. It is worth noting that the control method for the third compressor unit 51, reheater 56, and reheat expansion valve 58 in a condensing reheat air conditioner is prior art and can be referenced in the inventor's prior invention patent CN118640592B, which will not be further described here.

[0090] This embodiment of the present invention uses adjustments to the openings of the first water valve 91, the second water valve 92, the third water valve 93, the reheat valve 57, and the reheat expansion valve 58, as well as the operating states of the first compressor unit 31, the second compressor unit 41, the third compressor unit 51, the electric heating section 6, and the humidification section 7 as control measures. The first opening OP1, the second opening OP2, the third opening OP3, the fourth opening OP4, and the fifth opening OP5 are manually set as reference values. The opening is a percentage of the valve's maximum flow rate.

[0091] In one embodiment of the present invention, OP1 < OP2 < OP3 < OP4. Optionally, OP1 is 0-20%, OP2 is 20-40%, OP3 is 40-60%, and OP4 is 60-80%. Preferably, OP1 is 10%, OP2 is 30%, OP3 is 50%, and OP4 is 70%. OP5 is an independent reference applied to the reheat expansion valve 58.

[0092] like Figure 6 As shown, an embodiment of the present invention provides a control method for a water-cooled deep dehumidification air conditioner, comprising the following steps.

[0093] Step S1: Start the supply air fan 81 to the preset power of the fan, and the controller 90 collects and calculates in real time the target moisture content dob, the inlet air moisture content den, the supply air moisture content dex, the target air temperature tob, the inlet air temperature ten, the supply air temperature tex, the target temperature difference △Tob, the inlet water temperature Ten of each refrigeration section, the outlet water temperature Tex and the inlet and outlet water temperature difference △Twa; and when it is determined that den<dob and ten<tob, go to step S7; when den=dob and ten=tob, repeat step S1; otherwise, go to step S2.

[0094] When den < dob, ten < tob, it means that the incoming air does not need to be cooled and dehumidified, so it goes directly to step S7 for heating and humidification. When den = dob, ten = tob, it means that the temperature and humidity of the incoming air meet the expectations and no further processing is required, so it repeats step S1.

[0095] like Figure 7 As shown, preferably, this step includes the following sub-steps:

[0096] Sub-step S11: Start the air supply fan 81 to the preset fan power.

[0097] When the air supply fan is started, the air in the water-cooled deep dehumidification air conditioner will flow.

[0098] Sub-step S12: The controller 90 collects and calculates in real time the target moisture content dob, the inlet air moisture content den, the supply air moisture content dex, the target air temperature tob, the inlet air temperature ten, the supply air temperature tex, the target temperature difference ΔTob, the inlet water temperature Ten of each refrigeration section, the outlet water temperature Tex and the inlet and outlet water temperature difference ΔTwa.

[0099] Sub-step S13: Compare den with dob, ten with tob; when den < dob, and ten < tob, go to step S7; when den = dob, and ten = tob, go to sub-step S12; otherwise, go to step S2.

[0100] Step S2: When dob<den≤d1, start the third compressor unit to the initial frequency (for example, 30 Hz), and open the third water valve 93; when d1<den≤d2, start the third compressor unit 51 to the initial frequency, start one compressor of the second compressor unit 41, and open the second water valve 92 and the third water valve 93; when d2<den≤d3, start the third compressor unit 51 to the initial frequency, start all compressors of the second compressor unit 41, and open the second water valve 92 and the third water valve 93; when d3<den, start the third compressor unit 51 to the initial frequency, start all compressors of the second compressor unit 41, start the first compressor unit 31, and open the first water valve 91, the second water valve 92 and the third water valve 93.

[0101] The water-cooled deep dehumidification air conditioner provided by this invention primarily relies on the condensation and dehumidification of the condensation reheat section 5. Therefore, the condensation and reheat section 5 is activated whenever there is a dehumidification demand (dob < den). Depending on the required cooling capacity, the second-stage refrigeration section 4 and the first-stage refrigeration section 3 are activated sequentially, serving as pre-cooling sections for the condensation and reheat section 5. This allows the second-stage refrigeration section 4 and the first-stage refrigeration section 3 to be activated and deactivated based on real-time humidity data, thereby saving energy.

[0102] When opening each water valve as mentioned above, when Ten≤T1 of the refrigeration section where the water valve is located, the initial opening of the water valve is OP1; when T1<Ten≤T2, the initial opening of the water valve is OP2; when T2<Ten≤T3, the initial opening of the water valve is OP3; when T3<Ten, the initial opening of the water valve is OP4.

[0103] The water valves of the cooling sections that are not opened remain closed.

[0104] Step S3: Based on the moisture content read and calculated in real time, it is determined that when dex=dob, the operating frequency of the third compressor unit is maintained unchanged; when dex<dob, the operating frequency of the third compressor unit 51 is reduced according to the humidification design value; when dob<dex, the operating frequency of the third compressor unit 51 is increased according to the dehumidification design value.

[0105] Step S4: Obtain the high pressure HP in real time; when P1<HP<P2, maintain the opening of the third water valve 93 unchanged; when P2≤HP, increase the opening of the third water valve 93 according to the flow increase design value to increase the water volume, thereby increasing the heat exchange; when HP≤P1, reduce the opening of the third water valve 93 according to the flow reduction design value to reduce the water volume, thereby reducing the heat exchange.

[0106] The opening of the third water valve 93 is controlled according to the pressure of the pressure sensor 59 of the condensing and reheating section 5, so as to take into account the different heat exchange requirements of the refrigerant when the reheater 56 is open and closed.

[0107] For example, when the reheater 56 (reheat valve 57) is closed, the refrigerant in the condensing and reheating section 5 is cooled by the third water-cooled heat exchanger 52. When the third water valve 93 is opened wide, the water flow through the third water-cooled heat exchanger 52 is high, resulting in a lower refrigerant temperature after heat exchange. This results in a lower outlet pressure (HP) at the third compressor unit 51. In this case, the opening of the third water valve 93 can be reduced to conserve water while maintaining the refrigerant temperature within the designed range.

[0108] When the third water valve 93 is open slightly, the water flow rate through the third water-cooled heat exchanger 52 is low, resulting in a higher refrigerant temperature after heat exchange. This results in a higher outlet pressure (HP) at the third compressor unit 51. In this case, the opening of the third water valve 93 can be increased to increase the water flow while maintaining the refrigerant temperature within the designed range.

[0109] When reheater 56 (reheat valve 57) is open, a portion of the refrigerant is diverted to reheater 56 for heat exchange. This increases the refrigerant's heat exchange area and efficiency, lowering the refrigerant temperature. This is reflected by a decrease in the outlet pressure (HP) of the third compressor unit 51. At this point, the opening of the third water valve 93 can be reduced to conserve water while maintaining the refrigerant temperature within the designed range.

[0110] It's worth noting that the third pressure sensor 59 also serves as an auxiliary device for the third compressor unit 51, detecting its outlet pressure for adjusting the operating frequency and providing pressure protection. This embodiment of the present invention uses high pressure HP as the reference for controlling the opening of the third water valve 93, eliminating the need for a dedicated sensor for controlling the third water valve 93 and better meeting the requirements of the condensing reheat section 5.

[0111] Step S5: Obtain the opening OPex of the reheat expansion valve 58 in real time; when tex=tob, maintain the opening of the reheat expansion valve 58 unchanged; when tex<tob, increase the opening of the reheat expansion valve 58 according to the temperature increase design value; when tob<tex, reduce the opening of the reheat expansion valve 58 according to the temperature decrease design value; when OPex≤OP5, close the reheat valve; when OP5<OPex, open the reheat valve.

[0112] Because of the presence of reheater 56 and its branch piping, a small amount of refrigerant will leak into reheater 56 even when reheat valve 57 is closed. Therefore, reheat expansion valve 58 must be maintained at a small opening (essentially no opening) to allow refrigerant leaking into reheater 56 to flow back into the compressor, thus avoiding refrigerant imbalance and affecting the system's cooling capacity. Therefore, the opening and closing of reheat valve 57 are controlled based on the opening of reheat expansion valve 58.

[0113] Step S6: For the first refrigeration section 3 and / or the second refrigeration section 4 that has been opened, when △Twa=△Tob of the refrigeration section, the opening of the first water valve 91 and / or the second water valve 92 is maintained unchanged; when △Twa<△Tob, the first water valve 91 and / or the second water valve 92 is opened at a lower degree according to the design value of the temperature increase difference, thereby reducing the flow rate through the water valve; when △Tob<△Twa, the first water valve and / or the second water valve is opened at a higher degree according to the design value of the temperature reduction difference, thereby increasing the flow rate through the water valve.

[0114] The cooling sections that are not turned on remain unchanged.

[0115] Step S7: When tex<tob, turn on the electric heating section to the required power; when dex<dob, turn on the humidification section to the required humidification amount; go to step S1.

[0116] The primary purpose of this step is to provide heating and humidification functions, meeting operating conditions requiring only heating and humidification of the incoming air. A secondary purpose is to compensate for the insufficient heating capacity of the reheater 56 by further increasing the supply air temperature using the electric heating section 6. Therefore, this step also includes the following sub-steps:

[0117] Sub-step S71: When tex<tob and the reheat expansion valve reaches the maximum opening, enter sub-step S72; when tex<tob and the third compressor unit is not turned on, enter sub-step S72; otherwise, enter sub-step S73.

[0118] When tex<tob and the reheat expansion valve reaches the maximum opening, it means that the heating capacity of the reheater 56 alone is no longer able to increase the supply air temperature tex to the target air temperature tob, and the electric heating section 6 needs to be turned on to supplement heat.

[0119] When tex<tob, the third compressor unit 51 is not turned on, which means that the condensation and dehumidification function is not turned on in this working condition, and only the electric heating section 6 needs to be turned on to increase the supply air temperature tex.

[0120] When tex<tob and the reheat expansion valve has not reached the maximum opening, it means that the heating function of the reheater 56 is turned on in this operating condition, and its heating capacity still has room to continue to increase, and there is no need to increase the supply air temperature tex by the electric heating section 6.

[0121] It is worth noting that there are many control methods to achieve the maximum opening of the reheat expansion valve 58 before starting the electric heating section 6, such as controlling the start and stop of the electric heating section 6 by the opening of the reheat expansion valve 58, or by setting different sensor acquisition frequencies, which will not be repeated here.

[0122] Sub-step S72: Turn on the electric heating section to the required power.

[0123] Sub-step S73: When dex<dob, and the third compressor unit is not turned on, the humidification section is turned on to the required humidification amount; go to step S1.

[0124] It is worth noting that the order of steps S3 through S6 provided in the embodiment of the present invention can be changed according to actual needs. The order of the steps can also be changed, and serial processing can be changed to parallel processing. The order of the steps is not limited to the order listed in the embodiment. When the air supply blower is not started, the first water valve 91, the second water valve 92, the third water valve 93, and the reheat valve 57 provided in the embodiment of the present invention are all closed (blocked), and the first compressor unit 31, the second compressor unit 41, and the third compressor unit 51 are all in a stopped state.

[0125] The control methods of each refrigeration section are described below.

[0126] For the condensing reheat section 5: when dob < den, start the third compressor unit 51 to the design frequency; when Ten ≤ T1 of the condensing reheat section 5, the initial opening of the third water valve 93 is OP1; when T1 < Ten ≤ T2, the initial opening of the third water valve 93 is OP2; when T2 < Ten ≤ T3, the initial opening of the third water valve 93 is OP3; when T3 < Ten, the initial opening of the third water valve 93 is OP4;

[0127] When dex=dob, the operating frequency of the third compressor unit is maintained unchanged; when dex<dob, the operating frequency of the third compressor unit is reduced; when dob<dex, the operating frequency of the third compressor unit is increased;

[0128] When P1<HP<P2, the opening of the third water valve remains unchanged; when P2≤HP, the opening of the third water valve increases; when HP≤P1, the opening of the third water valve decreases;

[0129] When tex=tob, maintain the opening of the reheat expansion valve unchanged; when tex<tob, increase the opening of the reheat expansion valve according to the design value; when tob<tex, reduce the opening of the reheat expansion valve according to the design value; when OPex≤OP5, close the reheat valve; when OP5<OPex, open the reheat valve.

[0130] For the second refrigeration section 4: when d1<den≤d2, one compressor of the second compressor group is turned on; when d2<den≤d3, all compressors of the second compressor group are turned on; when Ten≤T1 of the second refrigeration section 4, the initial opening of the second water valve 92 is OP1; when T1<Ten≤T2, the initial opening of the second water valve 92 is OP2; when T2<Ten≤T3, the initial opening of the second water valve 92 is OP3; when T3<Ten, the initial opening of the second water valve 92 is OP4;

[0131] When ΔTwa=ΔTob of the second refrigeration section 4, the opening of the second water valve 92 is maintained unchanged; when ΔTwa<ΔTob, the opening of the second water valve 92 is reduced; when ΔTob<ΔTwa, the opening of the second water valve 92 is increased.

[0132] For the first refrigeration section 3: when d3 < den, start the first compressor unit; when Ten ≤ T1 of the first refrigeration section 3, the initial opening of the first water valve 91 is OP1; when T1 < Ten ≤ T2, the initial opening of the first water valve 91 is OP2; when T2 < Ten ≤ T3, the initial opening of the first water valve 91 is OP3; when T3 < Ten, the initial opening of the first water valve 91 is OP4;

[0133] When ΔTwa=ΔTob of the first refrigeration section 3, the opening of the first water valve 91 is maintained unchanged; when ΔTwa<ΔTob, the opening of the first water valve 91 is reduced; when ΔTob<ΔTwa, the opening of the first water valve 91 is increased.

[0134] When the present invention is started, the moisture content is used as a judgment basis to determine which stage of refrigeration to start according to the moisture content of the inlet air; after operation, the water system adjustment of the first and second stage refrigeration is controlled according to the temperature difference between the inlet and return water, so that the temperature difference is controlled at about 5°C; the water system adjustment of the third stage refrigeration is based on the high pressure of the third stage compressor as a judgment basis to achieve control of the water valve opening; finally, the dehumidification heat compensation function uses the opening of the electronic expansion valve as a judgment basis to ensure that the outlet air temperature and humidity are maintained near the target value.

[0135] Usually, the underground space is far away from the open space on the ground. If a compressor and an air-cooled radiator are set up in the open space on the ground and the high-pressure refrigerant is transported to the underground space for cooling and heat exchange, a long pressure-maintaining and heat-insulating pipeline needs to be set up, which is costly and has poor cooling efficiency (there is cooling loss along the way). The existing technology mostly sets up a refrigeration station in the open space (ground) and transports chilled water to a small space (tunnel working surface) for cooling and heat exchange. Although the chilled water pipeline is a normal-pressure pipeline, insulation measures are still required. The water-cooled deep dehumidification air conditioner provided in the embodiment of the present invention sets the compressor in the underground space, uses normal-temperature water and a plate heat exchanger as the cold source, and the water system pipeline is a normal-pressure pipeline, which does not require insulation, so the cost is low and the cooling efficiency is high. At the same time, in the water system of the embodiment of the present invention, if the normal-temperature water is taken from underground water, it can further simplify the water system pipeline and share the load of water discharge.

[0136] Calculations show that to achieve the same heat exchange rate, the heat exchange area of ​​the plate heat exchanger required in the present invention (water-cooled system) is only 25% to 27% of the heat exchange area of ​​the condenser in a traditional air-cooled system. This reduces the space required, saving valuable underground engineering space. Furthermore, the present invention boasts a COP of 4.5 to 5.0, compared to 3.0 to 3.5 for traditional air-cooled systems, significantly reducing energy consumption. Overall, for the same heat exchange rate, the present invention achieves 1.42 to 1.5 times the dehumidification capacity of traditional air-cooled systems, offering significant economic benefits.

[0137] Furthermore, this invention addresses the difficulty of maintaining an outlet air temperature around 7°C in traditional air cooling systems. This is because traditional air cooling systems struggle to maintain an evaporator temperature between 3 and 5°C for extended periods and are prone to evaporator freezing. Addressing this issue requires a significantly larger air cooling heat exchange system, increasing costs several times over, to remove the evaporator's cold air in a timely manner to prevent freezing, making it uneconomical. Furthermore, the increased air volume means the outlet air temperature cannot be maintained at a low enough level, failing to meet the target temperature requirement. Therefore, traditional air cooling systems are unable to address the dehumidification and low-temperature air delivery requirements of specialized applications, such as underground projects.

[0138] In summary, the water-cooled deep dehumidification air conditioner and its control method provided by the embodiments of the present invention achieve deep dehumidification through an optimized refrigeration cycle system and a high-efficiency evaporator and water-cooled condenser. This system can reduce indoor humidity to a low level and maintain a stable level, meeting the requirements of locations with strict humidity requirements. The intelligent control system precisely adjusts the operating status of various air conditioner components based on real-time humidity and temperature data, improving the accuracy of dehumidification and temperature control while also achieving energy-saving operation and reducing energy consumption and operating costs.

[0139] It should be noted that the above embodiments are merely examples, and the technical solutions of the various embodiments may be combined and are all within the scope of protection of the present invention.

[0140] It should be noted that the order of the steps of the present invention can be changed according to actual needs, the order between the steps can be changed, and serial processing can be changed to parallel processing, and is not limited to the order of the steps listed in the embodiments.

[0141] The terms "depth", "up", "down", "horizontal", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only used to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, they should not be understood as limiting the present invention.

[0142] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features being referred to. Thus, features specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0143] The above describes in detail a water-cooled deep dehumidification air conditioner and its control method provided by the present invention. For those skilled in the art, any obvious modification made thereto without departing from the essence of the present invention would constitute an infringement of the patent rights of the present invention and would result in corresponding legal liability.

Claims

1. A control method for a water-cooled deep dehumidification air conditioner, characterized in that Applied to a water-cooled deep dehumidification air conditioner; wherein, The water-cooled deep dehumidification air conditioner includes an air intake section, a filtration section, a first-stage refrigeration section, a second-stage refrigeration section, a condensation reheat section, an electric heating section, a humidification section, a blower section and a water system; wherein, The air inlet section, the filtration section, the first-stage refrigeration section, the second-stage refrigeration section, the condensation and reheating section, the electric heating section, the humidification section and the blower section are sequentially connected along the air path; The first-stage refrigeration section, the second-stage refrigeration section and the condensing and reheating section all include independent refrigeration systems; The water system includes a controller, a first water valve, a second water valve, a third water valve, a first temperature sensor, a second temperature sensor, and a third temperature sensor; the water system is connected to the first-stage refrigeration section through the first water valve, and the first temperature sensor obtains the inlet and outlet water temperatures of the first-stage refrigeration section; the water system is connected to the second-stage refrigeration section through the second water valve, and the second temperature sensor obtains the inlet and outlet water temperatures of the second-stage refrigeration section; the water system is connected to the condensing reheat section through the third water valve, and the third temperature sensor obtains the inlet and outlet water temperatures of the condensing reheat section; The control method of the water-cooled deep dehumidification air conditioner comprises the following steps: Step S1: Start the air supply fan to the preset fan power, and the controller collects and calculates in real time the target moisture content dob, the inlet air moisture content den, the supply air moisture content dex, the target air temperature tob, the inlet air temperature ten, the supply air temperature tex, the target temperature difference ΔTob, the inlet water temperature Ten, the outlet water temperature Tex, and the inlet and outlet water temperature difference ΔTwa of each cooling section; and when it is determined that den is less than dob and ten is less than tob, go to step S7; when den is equal to dob and ten is equal to tob, repeat step S1; otherwise, go to step S2; The formula for calculating moisture content is d=0.622Φps / (B-Φps) Where d is the moisture content, Φ is the relative humidity, ps is the saturated partial pressure of water vapor, and B is the atmospheric pressure; Calculation formula for water vapor saturation partial pressure ps=140974000×(exp(-3928.5 / (231.667+t))) Where t is the temperature; Step S2: When dob<den≤d1, start the third compressor unit to the initial frequency and open the third water valve; when d1<den≤d2, start the third compressor unit to the initial frequency, start one compressor of the second compressor unit, and open the second water valve and the third water valve; when d2<den≤d3, start the third compressor unit to the initial frequency, start all compressors of the second compressor unit, and open the second water valve and the third water valve; when d3<den, start the third compressor unit to the initial frequency, start all compressors of the second compressor unit, start the first compressor unit, and open the first water valve, the second water valve, and the third water valve; When opening each water valve, if Ten≤T1 of the cooling section where the water valve is located, the initial opening of the water valve is OP1; if T1<Ten≤T2, the initial opening of the water valve is OP2; if T2<Ten≤T3, the initial opening of the water valve is OP3; if T3<Ten, the initial opening of the water valve is OP4; Step S3: Based on the moisture content read and calculated in real time, when dex=dob, the operating frequency of the third compressor unit is maintained unchanged; when dex<dob, the operating frequency of the third compressor unit is reduced according to the humidification design value; when dob<dex, the operating frequency of the third compressor unit is increased according to the dehumidification design value; Step S4: obtaining the high pressure HP in real time; when P1 < HP < P2, maintaining the opening of the third water valve unchanged; when P2 ≤ HP, increasing the opening of the third water valve according to the flow increase design value to increase the water flow, thereby increasing the heat exchange; when HP ≤ P1, decreasing the opening of the third water valve according to the flow reduction design value to reduce the water flow, thereby reducing the heat exchange; Step S5: Obtain the opening of the reheat expansion valve OPex in real time; when tex = tob, maintain the opening of the reheat expansion valve unchanged; when tex < tob, increase the opening of the reheat expansion valve according to the temperature increase design value; when tob < tex, reduce the opening of the reheat expansion valve according to the temperature decrease design value; when OPex ≤ OP5, close the reheat valve; when OP5 < OPex, open the reheat valve; Step S6: For the first refrigeration section and / or the second refrigeration section that has been turned on, when ΔTwa=ΔTob of the refrigeration section, the opening of the first water valve and / or the second water valve is maintained unchanged; when ΔTwa<ΔTob, the opening of the first water valve and / or the second water valve is reduced according to the design value of the temperature increase difference, thereby reducing the flow rate through the water valve; when ΔTob<ΔTwa, the opening of the first water valve and / or the second water valve is increased according to the design value of the temperature reduction difference, thereby increasing the flow rate through the water valve; The unopened refrigeration sections remain unchanged; Step S7: When tex<tob, turn on the electric heating section to the required power; when dex<dob, turn on the humidification section to the required humidification amount; go to step S1.

2. The control method of the water-cooled deep dehumidification air conditioner according to claim 1, characterized in that The step S1 includes the following sub-steps: Sub-step S11: starting the air supply fan to a preset fan power; Sub-step S12: The controller collects and calculates in real time the target moisture content dob, the inlet air moisture content den, the supply air moisture content dex, the target air temperature tob, the inlet air temperature ten, the supply air temperature tex, the target temperature difference ΔTob, the inlet water temperature Ten, the outlet water temperature Tex, and the inlet and outlet water temperature difference ΔTwa of each cooling section; Sub-step S13: Compare den with dob, ten with tob; when den < dob, and ten < tob, go to step S7; When den = dob, and ten = tob, go to sub-step S12; Otherwise, go to step S2.

3. The control method of the water-cooled deep dehumidification air conditioner according to claim 1, characterized in that The step S7 includes the following sub-steps: Sub-step S71: When tex<tob and the reheat expansion valve reaches the maximum opening, proceed to sub-step S72; when tex<tob and the third compressor unit is not turned on, proceed to sub-step S72; otherwise, proceed to sub-step S73; Sub-step S72: turning on the electric heating section to the required power; Sub-step S73: When dex<dob, and the third compressor unit is not turned on, the humidification section is turned on to the required humidification amount; go to step S1.

4. The control method of a water-cooled deep dehumidification air conditioner according to any one of claims 1 to 3, characterized in that The water-cooled deep dehumidification air conditioner includes the following features: The air inlet section is an air inlet device, including an air inlet section temperature sensor and an air inlet section relative humidity sensor, for introducing external air and measuring the air inlet temperature and air inlet relative humidity; The filtering section is an air filtering device; the electric heating section is an air heating device; the humidifying section is an air humidifying device; The blower section is an air supply device, including an air supply fan, an air supply section temperature sensor and an air supply section relative humidity sensor, which are used to supply air and measure the supply air temperature and the supply air relative humidity.

5. The control method of the water-cooled deep dehumidification air conditioner according to claim 4, characterized in that The first stage refrigeration section of the water-cooled deep dehumidification air conditioner includes a first compressor unit, a first water-cooled heat exchanger, a first liquid storage tank, a first evaporator and a first gas-liquid separator; wherein, The outlet of the first compressor unit is connected to the refrigerant pipeline inlet of the first water-cooled heat exchanger, the refrigerant pipeline outlet of the first water-cooled heat exchanger is connected to the inlet of the first liquid storage tank, the outlet of the first liquid storage tank is connected to the inlet of the first evaporator, the outlet of the first evaporator is connected to the inlet of the first gas-liquid separator, and the outlet of the first gas-liquid separator is connected to the inlet of the first compressor unit; The first water valve is connected to the heat exchange medium pipeline of the first water-cooled heat exchanger.

6. The control method of the water-cooled deep dehumidification air conditioner according to claim 4, characterized in that The second-stage refrigeration section of the water-cooled deep dehumidification air conditioner includes a second compressor unit, a second water-cooled heat exchanger, a second liquid storage tank, a second evaporator and a second gas-liquid separator; wherein, The outlet of the second compressor unit is connected to the refrigerant pipeline inlet of the second water-cooled heat exchanger, the refrigerant pipeline outlet of the second water-cooled heat exchanger is connected to the inlet of the second liquid storage tank, the outlet of the second liquid storage tank is connected to the inlet of the second evaporator, the outlet of the second evaporator is connected to the inlet of the second gas-liquid separator, and the outlet of the second gas-liquid separator is connected to the inlet of the second compressor unit; The second water valve is connected to the heat exchange medium pipeline of the second water-cooled heat exchanger; The second compressor unit includes a plurality of fixed-frequency compressors.

7. The control method of the water-cooled deep dehumidification air conditioner according to claim 4, characterized in that The condensing and reheating section of the water-cooled deep dehumidification air conditioner includes a third compressor unit, a third water-cooled heat exchanger, a third liquid storage tank, a third evaporator, a third gas-liquid separator and a reheater; wherein, The outlet of the third compressor group is connected to the refrigerant pipeline inlet of the third water-cooled heat exchanger, the refrigerant pipeline outlet of the third water-cooled heat exchanger is connected to the inlet of the third liquid storage tank, the outlet of the third liquid storage tank is connected to the inlet of the third evaporator, the outlet of the third evaporator is connected to the inlet of the third gas-liquid separator, and the outlet of the third gas-liquid separator is connected to the inlet of the third compressor group; The inlet of the reheater is connected to the outlet of the third compressor unit, and the outlet of the reheater is connected to the inlet of the third evaporator; the reheater is arranged in the downstream direction of the third evaporator; The third water valve is connected to the heat exchange medium pipeline of the third water-cooled heat exchanger; The third compressor unit includes one or more variable frequency compressors.

8. The control method of the water-cooled deep dehumidification air conditioner according to claim 7, characterized in that The condensing and reheating section of the water-cooled deep dehumidification air conditioner further includes a reheat valve, a reheat expansion valve and a pressure sensor; wherein, The reheat valve is arranged between the third water-cooled heat exchanger and the inlet of the reheater; the reheat expansion valve is arranged between the outlet of the reheater and the inlet of the third evaporator; the pressure sensor is arranged on the output pipeline of the third compressor unit and is connected to the controller.

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