Evaporative condensation magnetic suspension multi-connected air conditioning unit and control method

Abstract

The present disclosure relates to the field of air conditioning and refrigeration technology, and particularly relates to an evaporative condensing magnetic suspension multi-connected air conditioning unit and a control method. The unit contains an outdoor main unit and at least two indoor terminals. The outdoor main unit integrates an evaporative condenser, a magnetic suspension compressor, a fluorine pump and a main control module. Each module is equipped with multiple types of sensors, pressure control components and temperature control components. The indoor terminal is provided with an evaporator coil and other suitable refrigerant pipelines. The main control module switches the unit to four operating modes, i.e. compressor mode, mixed mode, fluorine pump wet mode and fluorine pump dry mode, according to the outdoor ambient temperature and the average refrigeration demand of the indoor terminal. Each mode starts and stops the components as needed and precisely controls the parameters. The present disclosure realizes outdoor centralized heat dissipation, maximizes the use of natural cold sources, improves the energy efficiency and space utilization of the unit, reduces the noise in the machine room, solves the problems of inaccurate temperature control of multiple terminals and unstable system operation, and adapts to the uninterrupted refrigeration demand of the machine room throughout the year.

Description

Technical Field

[0001] This disclosure relates to the field of air conditioning and refrigeration technology, and in particular to an evaporative condensing magnetic levitation multi-split air conditioning unit and its control method. Background Technology

[0002] As the global energy crisis intensifies, energy conservation and emission reduction have become the core development direction of the air conditioning industry. In particular, data center and other computer room scenarios place stringent requirements on the temperature control accuracy, operating energy efficiency, reliability and space utilization of air conditioners.

[0003] Traditional computer room air conditioning systems have many technical defects: 1) The outdoor side generally uses air-cooled condensers, which have low heat dissipation efficiency, high overall unit energy consumption, and are mostly independent "one-to-one" systems, with a large outdoor footprint and low space utilization; 2) They do not integrate natural cold source utilization devices, and still rely on compressor operation even when the outdoor temperature is low, so energy efficiency cannot be further improved; 3) They mostly use traditional oil-lubricated compressors built into the computer room, which not only have low operating energy efficiency, but also generate a lot of noise in the computer room, affecting the operating environment of the computer room equipment; 4) If an evaporative condensing structure is used, its spray water is prone to freezing at low temperatures and water quality deterioration, which leads to system instability and lacks effective auxiliary control measures; 5) In multi-split air conditioning systems, the cooling demand of multiple terminals cannot be accurately matched, which easily leads to hot spots where the temperature of a single terminal exceeds the limit, and the flow control of the main pipeline and the refrigerant pipeline of the terminal lacks coordination.

[0004] In existing technologies, some air conditioners attempt to combine evaporative condensation with a compressor, or add a refrigerant pump to utilize natural cold sources. However, these are all simple superpositions of single functions, failing to achieve an integrated design of evaporative condensation + magnetic levitation compressor + refrigerant pump. They also fail to achieve intelligent switching of multiple modes based on outdoor temperature, and cannot solve problems such as terminal hotspots in multi-split systems, refrigerant pump-compressor coordination, and evaporative condensation auxiliary control. As a result, they cannot meet the high-efficiency, energy-saving, stable, and reliable requirements for year-round cooling in computer rooms.

[0005] Therefore, there is an urgent need to develop an integrated and intelligent multi-split air conditioning unit and control method to achieve centralized outdoor heat dissipation, maximize the utilization of natural cold sources, multi-mode low-energy operation, and precise temperature control at multiple terminals, while solving problems such as computer room noise, equipment footprint, and system stability. Summary of the Invention

[0006] To address the aforementioned deficiencies in existing technologies, this disclosure provides an evaporative condensing magnetic levitation multi-split air conditioning unit and its control method. This solves the technical problems of traditional computer room air conditioning, such as low energy efficiency, large outdoor footprint, high noise in the computer room, unutilized natural cold sources, poor stability of the evaporative condensing system, and inaccurate temperature control at multiple terminals. This achieves high efficiency, energy saving, stability, reliability, precise temperature control, and low energy consumption operation throughout the year for computer room air conditioning.

[0007] On one hand, this disclosure proposes an evaporative condensing magnetic levitation multi-split air conditioning unit, including an outdoor unit and N indoor terminals. The outdoor unit and the indoor terminals are connected via refrigerant pipelines. The outdoor unit includes an evaporative condenser module, a magnetic levitation compressor module, a refrigerant pump module, and a main control module. An evaporative condensing fan 12 is provided on the upper part of the evaporative condenser module. Below the evaporative condensing fan 12, a spray element 11, an evaporative condensing coil 10, an outdoor temperature and humidity sensor 9, and a water tank are arranged in sequence. An evaporative condensing water pump 1 connects the water tank and the spray element 11. A water pan electric heater 2, a water tank temperature sensor 3, and a water quality sensor are also included. The detector 4, low level switch 5, and high level switch 8 are all located in the water tank. The drain solenoid valve 6 and inlet solenoid valve 7 are both connected to the water tank. The exhaust port of the magnetic levitation compressor 21 in the magnetic levitation compressor unit module is connected to the air inlet of the evaporator-condenser coil 10. The exhaust port of the magnetic levitation compressor 21 is also equipped with an exhaust pressure sensor 17, a high-pressure switch 18, and an exhaust temperature sensor 19. The air outlet of the evaporator-condenser coil 10 is connected in sequence to the liquid pipe dryer filter 25 and the liquid receiver 29. The liquid receiver 29 is connected to the indoor terminal via the fourth one-way valve 40 and the liquid circuit electric valve 39. The suction port of the magnetic levitation compressor 21 is also connected to the water tank. The system includes a suction pressure sensor 22 and a main unit suction temperature sensor 23, which are connected to the air outlet of the indoor terminal via a suction dryer filter 16. A branch line from the outlet of the suction dryer filter 16 is connected to the inlet of the evaporator-condenser coil 10, and this branch line contains a first check valve 14. The refrigerant pump module is connected in parallel with the refrigerant pipeline containing the fourth check valve 40. The refrigerant pump module includes a first refrigerant pump 34 and a second refrigerant pump 41 connected in parallel. The inlet of the refrigerant pump is connected to the receiver 29, and a refrigerant pump inlet pressure sensor 32 and a refrigerant pump inlet temperature sensor 33 are installed between them. The outlet of the refrigerant pump is connected to the outlet of the fourth check valve 40. The system is connected in parallel to a refrigerant pump outlet pressure sensor 37 and a refrigerant pump outlet temperature sensor 38, and then to a liquid circuit electric valve 39. Each indoor terminal includes an evaporator coil 53. The inlet of the evaporator coil 53 is connected to the liquid circuit electric valve 39 of the outdoor unit in sequence through an electronic expansion valve 50, a solenoid valve 49, a sight glass 48, and a dryer filter 47. The outlet of the evaporator coil 53 is connected in sequence to the terminal suction temperature sensor 55 and the outdoor unit's gas circuit electric valve 45 and suction dryer filter 16. The main control module is electrically connected to the above modules to realize signal acquisition, operating condition judgment, and linkage control.

[0008] Preferably, the magnetic levitation compressor 21 has a branch on the intake side, and a cooling solenoid valve 15 is provided in the branch, which is then connected to the liquid reservoir 29.

[0009] Preferably, an independent branch consisting of an eighth manual ball valve 43 is provided between the liquid reservoir 29 and the liquid circuit electric valve 39.

[0010] On the other hand, this disclosure also proposes a control method for an evaporative condensing magnetic levitation multi-split air conditioning unit, applied to the evaporative condensing magnetic levitation multi-split air conditioning unit as described above. The main control module intelligently switches the unit to compressor mode, mixed mode, refrigerant pump wet mode, or refrigerant pump dry mode based on the outdoor ambient temperature T and the average cooling demand of all indoor terminals, according to the threshold range of the outdoor ambient temperature T. In each mode, the module components are started and stopped as needed, and the operating parameters are adjusted. The cooling demand is calculated from the supply air temperature and return air temperature detected by each indoor terminal. When the cooling demand of a single terminal is >30%, the solenoid valve 49, electronic expansion valve 50, and supply fan 52 of that terminal are automatically opened.

[0011] Preferably, when the outdoor temperature T satisfies T>T1, T1 is taken as 25℃, the compressor mode is activated, the refrigerant pump module is shut down, the main control module opens the liquid circuit electric valve 39 and the gas circuit electric valve 45 and starts the magnetic levitation compressor 21; the refrigerant is compressed into high-temperature and high-pressure vapor by the magnetic levitation compressor 21, enters the evaporator-condenser coil 10 to release heat into medium-temperature and high-pressure liquid, and is delivered to the indoor terminal through the liquid line dryer filter 25, the liquid receiver 29, the fourth one-way valve 40, and the liquid circuit electric valve 39, and is throttled into low temperature liquid through the dryer filter 47, the sight glass 48, the solenoid valve 49, and the electronic expansion valve 50. The low-temperature, low-pressure gas-liquid mixture absorbs heat in the evaporator coil 53 to become low-temperature, low-pressure steam, which is then returned to the magnetic levitation compressor 21 via the suction dryer filter 16 to complete the refrigeration cycle. The magnetic levitation compressor 21 adjusts its speed according to the evaporation temperature calculated from the refrigerant pressure detected by the suction pressure sensor 22. The target evaporation temperature is 16°C. When the evaporation temperature is higher than the target value, the speed is increased, and when it is lower than the target value, the speed is decreased. The evaporator-condenser fan 12 adjusts its speed according to the refrigerant pressure detected by the exhaust pressure sensor 17. The fan starts when the refrigerant pressure is 5 bar and runs at full speed when the refrigerant pressure is 8.5 bar.

[0012] Preferably, when the outdoor temperature T satisfies T2<T≤T1, T2 is set to 10℃ and T1 is set to 25℃, and the mixed mode is operated; the control methods of the magnetic levitation compressor, evaporative condenser module, and indoor terminal are consistent with the compressor mode; the first refrigerant pump 34 is turned on to assist in cooling. The speed of the first refrigerant pump 34 is adjusted according to the pressure difference detected by the refrigerant pump inlet pressure sensor 32 and the refrigerant pump outlet pressure sensor 37. The target pressure difference is 3 bar. When the pressure difference is lower than 3 bar, the speed of the first refrigerant pump 34 is increased, and when the pressure difference is higher than 3 bar, the speed of the first refrigerant pump 34 is decreased; the unit also includes a second refrigerant pump 41 set in parallel with the first refrigerant pump 34 for redundancy design. When a fault is detected in the first refrigerant pump 34, the main control module automatically switches to the second refrigerant pump 41 for operation.

[0013] Preferably, when the outdoor temperature T satisfies T3 < T ≤ T2, T3 is -10℃ and T2 is 10℃, and the refrigerant pump operates in wet mode; the main control module opens the liquid circuit electric valve 39 and the gas circuit electric valve 45 and starts the first refrigerant pump 34; the refrigerant is delivered to the indoor terminal via the first refrigerant pump 34, and throttled by the dryer filter 47, sight glass 48, solenoid valve 49, and electronic expansion valve 50 to form a low-temperature, low-pressure gas-liquid mixture. It absorbs heat in the evaporator coil 53 to become low-temperature, low-pressure vapor, and then enters the evaporator-condenser coil 10 through the suction dryer filter 16 and the first one-way valve 14, releasing heat as a low-temperature, low-pressure liquid. It then flows back to the first refrigerant pump via the liquid receiver 29. Pump 34 completes the natural cold source refrigeration cycle; the first refrigerant pump 34 adjusts its speed according to the pressure difference detected by the refrigerant pump inlet pressure sensor 32 and the refrigerant pump outlet pressure sensor 37. The target pressure difference is 3.5 bar. When the pressure difference is lower than 3.5 bar, the speed is increased, and when it is higher than 3.5 bar, the speed is decreased; the evaporator-condenser fan 12 adjusts its speed according to the main unit's refrigeration demand using PID. It starts when the refrigeration demand is >30%, runs at full speed when it is >100%, and when the refrigeration demand of a single terminal is >150%, the evaporator-condenser fan 12 is forcibly accelerated to 130% of the current speed until the terminal demand is <100%, after which the PID adjustment is restored.

[0014] Preferably, when the outdoor temperature T satisfies T≤T3, and T3 is -10℃, the refrigerant pump operates in dry mode; the control methods of the refrigerant pump, indoor terminal, and evaporative condenser fan 12 are consistent with the refrigerant pump wet mode; the evaporative condenser pump 1 is turned off, and only the evaporative condenser fan 12 is used to provide dry cooling heat dissipation for the evaporative condenser coil, so as to achieve energy-saving and water-saving natural cold source cooling.

[0015] Preferably, the evaporative condensate pump 1 is switched on and off according to the outdoor temperature. The evaporative condensate pump 1 is turned on when the outdoor temperature is >-10℃, and turned off otherwise. The water pan electric heater 2 is turned on when the water tank temperature sensor detects a value <2℃ to prevent the spray water from freezing. When the water quality detector 4 detects that the water quality exceeds the limit, the main control module controls the drain solenoid valve 6 and the inlet solenoid valve 7 to open to realize automatic water replacement in the water tank.

[0016] Preferably, the air supply fan 52 of each indoor terminal adjusts its speed according to the temperature difference between the supply and return air. The temperature difference threshold is 13°C. When the temperature difference is higher than 13°C, the speed is increased, and when it is lower than 13°C, the speed is decreased. The liquid circuit electric valve 39 adjusts the refrigerant flow rate of the main pipeline according to the superheat of the main pipeline suction. Each terminal electronic expansion valve adjusts the branch flow rate according to its own target superheat.

[0017] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain the preferred examples of this disclosure.

[0018] The above technical solution has the following advantages or beneficial effects: 1. High space utilization and low noise in the computer room: It adopts a multi-split structure, integrating all core equipment such as evaporative condenser, magnetic levitation compressor, and refrigerant pump on the outdoor side to achieve centralized heat dissipation outdoors. Compared with traditional air-cooled one-to-one air conditioners, it significantly reduces the outdoor space occupancy rate; the magnetic levitation compressor is placed outdoors, and only heat exchange coils and fans are installed at the indoor terminal, which completely solves the problem of high compressor noise in the computer room.

[0019] 2. High energy efficiency ratio and significantly reduced energy consumption: It adopts an oil-free magnetic levitation compressor, which saves 30%-40% more energy than traditional oil-cooled compressors; combined with an evaporative condenser, it uses spray water phase change heat dissipation, and the heat dissipation efficiency is much higher than that of traditional air-cooled condensers; it integrates a refrigerant pump system and realizes four-mode intelligent switching to maximize the use of natural cold source. In refrigerant pump mode, the compressor is completely shut down, which greatly reduces the overall operating power consumption of the machine.

[0020] 3. High system stability and low maintenance cost: The evaporative condenser integrates a linkage auxiliary control structure for water quality, liquid level, and temperature, realizing automatic water replacement, antifreeze, and liquid level control, solving the problems of spray water deterioration and freezing; the refrigerant pump adopts a redundant design, automatically switching in case of failure to ensure continuous system operation; the magnetic levitation compressor operates without oil, improving the reliability and service life of system components and reducing maintenance costs.

[0021] 4. Precise temperature control, adaptable to multi-terminal requirements: Adopting a dual-layer flow control structure of "main pipeline liquid circuit electric valve + terminal electronic expansion valve" to achieve precise matching of total refrigerant flow and branch flow; In response to the hot spot problem at the terminal of the multi-split system, a control strategy of forced speed increase of condenser fan is designed to avoid high temperature exceeding the limit at a single terminal and meet the temperature control accuracy requirements of the computer room.

[0022] 5. High level of intelligence, adaptable to year-round cooling: The main control module automatically and intelligently switches between four modes based on outdoor temperature and multi-terminal cooling needs, requiring no manual intervention. While meeting the year-round cooling and heat load of the data center, it always operates in the lowest energy consumption mode, adapting to the uninterrupted cooling needs of data centers and other computer rooms throughout the year. Of course, no single technical solution disclosed herein may necessarily achieve all of the advantages described above simultaneously. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on the provided drawings without any creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of an evaporative condensing magnetic levitation multi-split air conditioning unit according to an embodiment of the present disclosure.

[0025] Figure 2 This is a schematic diagram of the compressor operation mode of an evaporative condensing magnetic levitation multi-split air conditioning unit according to an embodiment of the present disclosure.

[0026] Figure 3 This is a schematic diagram of the mixed operation mode of an evaporative condensing magnetic levitation multi-split air conditioning unit according to an embodiment of the present disclosure.

[0027] Figure 4 This is a schematic diagram of an evaporative condensing magnetic levitation multi-split air conditioning unit operating in wet refrigerant pump mode according to an embodiment of the present disclosure.

[0028] Figure 5 This is a schematic diagram of an evaporative condensing magnetic levitation multi-split air conditioning unit operating in dry refrigerant pump mode according to an embodiment of the present disclosure.

[0029] The system includes: 1. Evaporative condensate pump; 2. Water pan electric heater; 3. Water tank temperature sensor; 4. Water quality analyzer; 5. Low liquid level switch; 6. Drain solenoid valve; 7. Inlet solenoid valve; 8. High liquid level switch; 9. Outdoor temperature and humidity sensor; 10. Evaporative condensate coil; 11. Spray unit; 12. Evaporative condensate fan; 13. First manual ball valve; 14. First check valve; 15. Cooling solenoid valve; 16. Suction air dryer filter; 17. Exhaust pressure sensor; 18. High pressure switch; 19. Exhaust temperature sensor; 20. Second check valve; 21. Magnetic levitation compressor; 22. Suction pressure sensor; 23. Main unit suction temperature sensor; 24. Second manual ball valve; 25. Liquid line dryer filter; 26. Third manual ball valve; 27. Fourth manual ball valve; 28. Fifth manual ball valve; and a liquid receiver. 29; Refrigerant level sensor; 30; Sixth manual ball valve; 31; Refrigerant pump inlet pressure sensor; 32; Refrigerant pump inlet temperature sensor; 33; First refrigerant pump; 34; Third check valve; 35; Seventh manual ball valve; 36; Refrigerant pump outlet pressure sensor; 37; Refrigerant pump outlet temperature sensor; 38; Liquid circuit electric valve; 39; Fourth check valve; 40; Second refrigerant pump; 41; Fifth check valve; 42; Eighth manual ball valve; 43; Ninth manual ball valve; 44; Gas circuit electric valve; 45; Tenth manual ball valve; 46; Dryer filter; 47; Sight glass; 48; Solenoid valve; 49; Electronic expansion valve; 50; Supply air temperature sensor; 51; Supply air fan; 52; Evaporator coil; 53; Return air temperature and humidity sensor; 54; Terminal suction air temperature sensor; 55; Eleventh manual ball valve; 56. Detailed Implementation

[0030] The technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely a part of the embodiments of this disclosure and are intended to explain the inventive concept. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.

[0031] The terms “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “axial,” “radial,” “circumferential,” “center,” “longitudinal,” “transverse,” “length direction,” “width direction,” and “thickness direction” used in the description indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are for the purpose of simplifying the description only and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation.

[0032] The terms "first," "second," etc., used in the description are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of that feature. The term "multiple" means two or more, unless otherwise explicitly specified.

[0033] Unless otherwise explicitly specified and limited, the terms "connected," "connected," etc., used in the description should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments according to the specific circumstances.

[0034] Unless otherwise explicitly specified and limited, the terms "above," "below," or "on top of" the second feature can mean that the first and second features are in direct contact or indirect contact through an intermediate medium. Furthermore, "above," "on top of," or "on top of" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," or "below" the second feature can mean that the first and second features are in direct contact or indirect contact through an intermediate medium. Moreover, "below," "below," or "below" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0035] The term "a specific embodiment" as used in the description means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0036] refer to Figure 1 One specific embodiment of this disclosure proposes an evaporative condensing magnetic levitation multi-split air conditioning unit, including an outdoor unit and N indoor terminals. The outdoor unit and the indoor terminals are connected via refrigerant piping, where N is a positive integer ≥ 2. The outdoor unit includes an evaporative condenser module, a magnetic levitation compressor module, a refrigerant pump module, and a main control module.

[0037] The evaporative condenser module includes an evaporative condensate pump 1, an electric water heater for the water pan 2, a water tank temperature sensor 3, a water quality analyzer 4, a low level switch 5, a drain solenoid valve 6, an inlet solenoid valve 7, a high level switch 8, an outdoor temperature and humidity sensor 9, an evaporative condenser coil 10, a spray system 11, and an evaporative condenser fan 12. The spray system 11 is located above the evaporative condenser coil 10, and the water tank is located below the evaporative condenser coil 10. The evaporative condensate pump 1 connects the water tank and the spray system 11. The electric water heater for the water pan 2, the water tank temperature sensor 3, the water quality analyzer 4, the low level switch 5, and the high level switch 8 are all located inside the water tank. The drain solenoid valve 6 and the inlet solenoid valve 7 are both connected to the water tank.

[0038] The magnetic levitation compressor unit module includes a magnetic levitation compressor 21, an intake air dryer filter 16, a liquid line dryer filter 25, and a liquid receiver 29. The exhaust port of the magnetic levitation compressor 21 is connected to the inlet of the evaporator-condenser coil 10. The exhaust port of the magnetic levitation compressor 21 is also equipped with an exhaust pressure sensor 17, a high-pressure switch 18, and an exhaust temperature sensor 19. The outlet of the evaporator-condenser coil 10 is connected to the liquid line dryer filter 25 and the liquid receiver 29 in sequence. The liquid receiver 29 is equipped with a refrigerant level sensor 30. The liquid receiver 29 is connected to the indoor terminal via a fourth one-way valve 40 and a liquid circuit electric valve 39. The intake port of the magnetic levitation compressor 21 is connected to the outlet of the indoor terminal via the intake air dryer filter 16. The intake port of the magnetic levitation compressor 21 is also equipped with an intake pressure sensor 22 and a main unit intake temperature sensor 23. The outlet of the intake air dryer filter 16 is also provided with a branch line connected to the inlet of the evaporator-condenser coil 10. This branch line is equipped with a first one-way valve 14.

[0039] The fluorine pump module is connected in parallel with the pipeline where the fourth check valve 40 is located. The fluorine pump module includes a first fluorine pump 34 and a second fluorine pump 41 connected in parallel. The two are redundantly designed. The inlet of the fluorine pump is connected to the liquid reservoir 29, and a fluorine pump inlet pressure sensor 32 and a fluorine pump inlet temperature sensor 33 are also provided between the two. The outlet of the fluorine pump is connected in parallel with the outlet of the fourth check valve 40, and then connected to a fluorine pump outlet pressure sensor 37 and a fluorine pump outlet temperature sensor 38, and then connected to the liquid circuit electric valve 39.

[0040] An independent branch line is added between the receiver 29 and the electric valve 39, connecting the receiver 29, the eighth manual ball valve 43, and the electric valve 39. This branch line is used to balance the pressure difference between the inlet and outlet of the refrigerant pump module, providing a stable pressure environment for the refrigerant pump operation. Additionally, in case of refrigerant pump failure or system maintenance, the pressure of the refrigerant pipeline can be adjusted and the flow path switched by opening and closing the eighth manual ball valve 43, further improving the operational reliability and maintenance convenience of the refrigerant pump module and the entire refrigerant circulation system.

[0041] The main control module is electrically connected to all the above modules and is used to collect detection signals, calculate cooling requirements, and control the operating status and parameters of each component.

[0042] Taking a single indoor terminal unit as an example, it includes an evaporator coil 53, a supply air fan 52, a supply air temperature sensor 51, a return air temperature and humidity sensor 54, a terminal suction air temperature sensor 55, a dryer filter 47, a sight glass 48, a solenoid valve 49, and an electronic expansion valve 50. The inlet of the evaporator coil 53 is connected to the liquid circuit electric valve 39 of the outdoor unit in sequence through the electronic expansion valve 50, the solenoid valve 49, the sight glass 48, and the dryer filter 47. The outlet of the evaporator coil 53 is connected to the terminal suction air temperature sensor 55 and the air circuit electric valve 45 and the suction air dryer filter 16 of the outdoor unit in sequence. The supply air fan 52 is located on the side of the evaporator coil 53. The sensors are used to detect the temperature, humidity, and refrigerant status of the terminal unit. The electronic expansion valve 50 is used to adjust the refrigerant flow rate of the terminal unit.

[0043] Preferably, the magnetic levitation compressor 21 has a branch line on the suction side, and a cooling solenoid valve 15 is provided in the branch line, which is then connected to the liquid receiver 29 to ensure the safe and stable operation of the compressor under high load and high exhaust temperature and pressure conditions.

[0044] Preferably, each piece of equipment is equipped with a manual ball valve at its inlet and outlet ends for easy system maintenance.

[0045] Based on the above-mentioned evaporative condensing magnetic levitation multi-split air conditioning unit, this disclosure also provides a control method in which the main control module intelligently switches the system to compressor mode, mixed mode, refrigerant pump wet mode, and refrigerant pump dry mode according to the detected outdoor temperature T and the average cooling demand of N indoor terminals. Under the premise of meeting the heat load requirements of the computer room, the system always operates in the lowest energy consumption mode.

[0046] refer to Figure 2 One specific embodiment of this disclosure proposes an evaporative condensing magnetic levitation multi-split air conditioning unit operating in compressor mode. When the outdoor temperature T satisfies T > T1, where T1 is 25°C, the system prioritizes compressor mode, and the refrigerant pump module is shut down.

[0047] (1) Each terminal in the room independently detects the supply air temperature and return air temperature to calculate the cooling demand. When the cooling demand of a single terminal is greater than 30%, the solenoid valve 49, electronic expansion valve 50, and supply air fan 52 of the terminal are automatically opened. (2) The main control module synchronously detects the cooling demand of each terminal. When the cooling demand of a single terminal is detected to be >30%, the liquid circuit electric valve 39 and the gas circuit electric valve 45 are opened to ensure that the system path is unobstructed and the magnetic levitation compressor 21 is started. The refrigerant is compressed into high temperature and high pressure vapor by the magnetic levitation compressor 21. The refrigerant vapor then enters the evaporator condenser coil 10 to release heat and become medium temperature and high pressure liquid refrigerant. It is then transported to the indoor terminal through the liquid line dryer filter 25, the liquid receiver 29, the fourth one-way valve 40, and the liquid circuit electric valve 39. It is throttled into a low temperature and low pressure gas-liquid mixture through the terminal dryer filter 47, the sight glass 48, the solenoid valve 49, and the electronic expansion valve 50. It absorbs heat in the evaporator coil 53 to become a low temperature and low pressure refrigerant vapor. The refrigerant flow rate is controlled according to the target superheat. It flows back to the magnetic levitation compressor 21 through the gas circuit electric valve 45 and the suction dryer filter 16 to complete the refrigeration cycle. (3) The magnetic levitation compressor 21 adjusts its speed according to the refrigerant pressure detected by the suction pressure sensor 22 and the evaporation temperature calculated by it. The target evaporation temperature is 16°C. When the evaporation temperature is higher than the target value, the speed is increased; when it is lower than the target value, the speed is decreased. (4) The evaporative condensate pump 1 is switched on and off according to the outdoor temperature. The evaporative condensate pump 1 is turned on when the outdoor temperature is >-10℃, otherwise it is turned off; the water pan electric heater 2 is turned on when the water tank temperature sensor detects a value <2℃ to prevent the spray water from freezing; when the water quality detector 4 detects that the water quality exceeds the limit, the main control module controls the drain solenoid valve 6 and the inlet solenoid valve 7 to open, realize the automatic water replacement of the water tank, ensure the water quality requirements of the spray device, and make the system operate stably for a long time. (5) The evaporator-condenser fan 12 controls the speed according to the refrigerant pressure detected by the exhaust pressure sensor 17; when the refrigerant pressure is detected to be 5 bar, the evaporator-condenser fan 12 is started; when the refrigerant pressure is detected to be 8.5 bar, the evaporator-condenser fan 12 runs at full speed; the terminal air supply fan 52 adjusts the speed according to the temperature difference between the supply and return air. The temperature difference threshold is 13℃. When the temperature difference is higher than 13℃, the speed of the air supply fan 52 is increased; when the temperature difference is lower than 13℃, the speed of the air supply fan 52 is decreased. (6) The liquid circuit electric valve 39 controls the switch according to the superheat of the main pipeline to adjust the refrigerant flow in the main pipeline. Each terminal electronic expansion valve 50 precisely adjusts the branch flow according to its own target superheat, ensuring stable operation of the system while meeting the cooling needs of each terminal.

[0048] refer to Figure 3 One specific embodiment of this disclosure proposes an evaporative condensing magnetic levitation multi-split air conditioning unit operating in a hybrid mode. When the outdoor temperature T satisfies T2 < T ≤ T1, where T2 is 10°C and T1 is 25°C, the system preferentially operates in hybrid mode.

[0049] (1) The control methods of the magnetic levitation compressor, evaporative condenser module, and indoor terminal are consistent with the compressor mode; (2) Start the first fluorine pump 34 to assist the magnetic levitation compressor 21 in providing cooling capacity, reduce the operating load of the magnetic levitation compressor 21, and thus achieve energy saving. The speed of the first fluorine pump 34 is adjusted according to the pressure difference detected by the fluorine pump inlet pressure sensor 32 and the fluorine pump outlet pressure sensor 37. The target pressure difference is 3 bar. When the pressure difference is lower than 3 bar, the speed of the first fluorine pump 34 is increased. When the pressure difference is higher than 3 bar, the speed of the first fluorine pump 34 is decreased. (3) The unit also includes a second fluorine pump 41 connected in parallel with the first fluorine pump 34 for redundancy design. When a fault is detected in the first fluorine pump 34, the main control module automatically switches to the second fluorine pump 41 to achieve fluorine pump redundancy protection and ensure that the system operates in a high-efficiency and energy-saving mode for a long time.

[0050] refer to Figure 4 One specific embodiment of this disclosure proposes an evaporative condensing magnetic levitation multi-split air conditioning unit operating in refrigerant pump wet mode. When the outdoor temperature T satisfies T3 < T ≤ T2, where T3 is -10°C and T2 is 10°C, the system prioritizes operating in refrigerant pump wet mode, shutting off the magnetic levitation compressor, fully utilizing the outdoor natural cold source to provide cooling output to the indoor unit, and significantly reducing the overall power consumption of the unit.

[0051] (1) Each terminal in the room independently detects its own supply air temperature and return air temperature and calculates the cooling demand. When the cooling demand is detected to be higher than 30%, the solenoid valve 49, electronic expansion valve 50, and supply fan 52 are automatically opened. (2) The host synchronously detects the cooling demand of each terminal. When the cooling demand of a single terminal is detected to be higher than 30%, the main control module opens the liquid circuit electric valve 39 and the gas circuit electric valve 45 to ensure that the system path is unobstructed. The first refrigerant pump 34 is started to transport low-temperature and low-pressure liquid refrigerant. The refrigerant is transported to the indoor terminal and passes through the terminal dryer filter 47, sight glass 48, solenoid valve 49 and electronic expansion valve 50 in sequence. The refrigerant is throttled and becomes a low-temperature and low-pressure gas-liquid mixture. At the same time, the refrigerant flow rate is controlled according to the target superheat. The refrigerant absorbs heat in the evaporator coil 53 and becomes a low-temperature and low-pressure refrigerant vapor. Then it passes through the suction dryer filter 16 and one-way valve 14 in sequence. The refrigerant releases heat in the evaporator condenser coil 10 and becomes a low-temperature and low-pressure refrigerant liquid. Then it flows back to the first refrigerant pump 34 through the liquid receiver 29 to complete the natural cold source refrigeration cycle. (3) The above-mentioned fluorine pump controls and adjusts the speed according to the pressure difference detected by the fluorine pump inlet pressure sensor 32 and the fluorine pump outlet pressure sensor 37. The target pressure difference is generally 3.5 bar. When the pressure difference is lower than 3.5 bar, the speed of the fluorine pump is increased. When the pressure difference is higher than 3.5 bar, the speed of the fluorine pump is decreased. The fluorine pump redundancy switching control is consistent with the mixing mode. (4) The evaporative condenser pump and the electric heater of the water pan are both turned on. The evaporative condenser fan 12 adjusts the fan speed according to the cooling demand of the host. When the cooling demand is detected to be >30%, the evaporative condenser fan 12 is started. When the cooling demand is >100%, the evaporative condenser fan 12 runs at full speed. In order to avoid the temperature of the terminal exceeding the limit, when the host detects that the cooling demand of a single terminal is >150%, the evaporative condenser fan 12 is forcibly accelerated to 130% of the current speed until the demand of the terminal is <100%, and then the PID adjustment is restored. This control is intended to solve the problem of high temperature at a certain terminal when there are multiple terminals in the device, so that the control of the whole system can be more precise. (5) The control mode of the terminal air blower 52 and electronic expansion valve 50 is the same as that of the compressor mode, and the evaporative condensate pump 1 and the water pan electric heater 2 are both in the on state.

[0052] refer to Figure 5 One specific embodiment of this disclosure proposes an evaporative condensing magnetic levitation multi-split air conditioning unit operating in refrigerant pump dry mode. When the outdoor temperature T satisfies T≤T3, where T3 is -10℃, the system preferentially operates in refrigerant pump dry mode; (1) The control methods of the refrigerant pump, indoor terminal, and evaporative condenser fan 12 are the same as those of the refrigerant pump in wet mode; (2) Turn off the evaporative condensate pump 1 and use only the evaporative condenser fan 12 to provide dry cooling heat to the evaporative condenser coil, so as to achieve energy-saving and water-saving natural cold source refrigeration.

[0053] Of course, the control method disclosed herein can also be adaptively adjusted according to the actual application scenario, adjusting the temperature switching thresholds T1, T2, T3 and the terminal cooling demand start threshold of the above four modes.

[0054] Although embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Various changes and modifications may be made to the present disclosure without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of the claimed disclosure.

Claims

1. An evaporative condensing magnetic levitation multi-split air conditioning unit, comprising an outdoor unit and N indoor terminals, wherein the outdoor unit and the indoor terminals are connected via refrigerant piping, and the outdoor unit comprises an evaporative condenser module, a magnetic levitation compressor module, a refrigerant pump module, and a main control module, characterized in that, The upper part of the evaporative condenser module is equipped with an evaporative condenser fan. Below the evaporative condenser fan, there are spray components, evaporative condenser coils, outdoor temperature and humidity sensors, and a water tank in sequence. The evaporative condenser water pump connects the water tank and the spray components. The water pan electric heater, water tank temperature sensor, water quality detector, low liquid level switch, and high liquid level switch are all located in the water tank. The drain solenoid valve and the inlet solenoid valve are both connected to the water tank. The exhaust port of the magnetic levitation compressor in the magnetic levitation compressor unit module is connected to the inlet of the evaporator-condenser coil. The exhaust port of the magnetic levitation compressor is also equipped with an exhaust pressure sensor, a high-pressure switch, and an exhaust temperature sensor. The outlet of the evaporator-condenser coil is connected in sequence to the liquid line dryer filter and the liquid receiver. The liquid receiver is connected to the indoor terminal via a fourth check valve and a liquid circuit electric valve. The suction port of the magnetic levitation compressor is equipped with a suction pressure sensor and a main unit suction temperature sensor. It is connected to the outlet of the indoor terminal via a suction dryer filter. The outlet of the suction dryer filter is also provided with a branch line connected to the inlet of the evaporator-condenser coil. This branch line is equipped with a first check valve. The refrigerant pump module is connected in parallel with the refrigerant pipeline where the fourth check valve is located. The refrigerant pump module includes a first refrigerant pump and a second refrigerant pump connected in parallel. The inlet of the refrigerant pump is connected to the liquid receiver and a refrigerant pump inlet pressure sensor and a refrigerant pump inlet temperature sensor are also installed between the two. The outlet of the refrigerant pump is connected in parallel with the outlet of the fourth check valve and is connected to a refrigerant pump outlet pressure sensor and a refrigerant pump outlet temperature sensor, and then connected to the liquid circuit electric valve. A single indoor terminal includes an evaporator coil. The inlet of the evaporator coil is connected to the liquid circuit electric valve of the outdoor unit in sequence through an electronic expansion valve, a solenoid valve, a sight glass, and a dryer filter. The outlet of the evaporator coil is connected to the terminal suction temperature sensor and the gas circuit electric valve and suction dryer filter of the outdoor unit in sequence. The main control module is electrically connected to the above modules to realize signal acquisition, operating condition judgment and linkage control.

2. The evaporative condensing magnetic levitation multi-split air conditioning unit according to claim 1, characterized in that, The magnetic levitation compressor has a branch line on the intake side, and a cooling solenoid valve is installed in the branch line, which is then connected to the liquid receiver.

3. The evaporative condensing magnetic levitation multi-split air conditioning unit according to claim 1, characterized in that, An independent branch consisting of an eighth manual ball valve is also provided between the liquid reservoir and the electric valve in the liquid circuit.

4. A control method for an evaporative condensing magnetic levitation multi-split air conditioning unit, applied to the evaporative condensing magnetic levitation multi-split air conditioning unit as described in any one of claims 1-3, characterized in that, The main control module intelligently switches the unit to compressor mode, mixed mode, refrigerant pump wet mode, or refrigerant pump dry mode based on the outdoor ambient temperature T and the average cooling demand of all indoor terminals, according to the threshold range of the outdoor ambient temperature T. In each mode, the module components are started and stopped as needed and the operating parameters are adjusted. The cooling demand is calculated from the supply air temperature and return air temperature detected by each indoor terminal. When the cooling demand of a single terminal is greater than 30%, the solenoid valve, electronic expansion valve and supply fan of that terminal are automatically turned on.

5. The control method for an evaporative condensing magnetic levitation multi-split air conditioning unit according to claim 4, characterized in that, When the outdoor temperature T meets the condition T > T1, T1 is set to 25℃. The compressor mode is activated, the refrigerant pump module is shut down, and the main control module opens the liquid circuit electric valve and the gas circuit electric valve and starts the magnetic levitation compressor. The refrigerant is compressed into high-temperature and high-pressure vapor by the magnetic levitation compressor, enters the evaporator-condenser coil and releases heat to become medium-temperature and high-pressure liquid. It is then transported to the indoor terminal through the liquid line dryer filter, liquid receiver, fourth check valve, and liquid circuit electric valve. After passing through the dryer filter, sight glass, solenoid valve, and electronic expansion valve, it is throttled into a low-temperature and low-pressure gas-liquid mixture. It absorbs heat in the evaporator coil to become low-temperature and low-pressure vapor, and returns to the magnetic levitation compressor through the suction dryer filter to complete the refrigeration cycle. The magnetic levitation compressor adjusts its speed according to the evaporation temperature calculated from the refrigerant pressure detected by the suction pressure sensor. The target evaporation temperature is 16℃. The speed is increased when the evaporation temperature is higher than the target value and decreased when it is lower than the target value. The evaporator-condenser fan adjusts its speed according to the refrigerant pressure detected by the exhaust pressure sensor. The fan starts when the refrigerant pressure is 5 bar and runs at full speed when the refrigerant pressure is 8.5 bar.

6. The control method for an evaporative condensing magnetic levitation multi-split air conditioning unit according to claim 4, characterized in that, When the outdoor temperature T satisfies T2<T≤T1, T2 is set to 10℃ and T1 to 25℃, and the mixed mode is operated. The control methods of the magnetic levitation compressor, evaporative condenser module, and indoor terminal are consistent with the compressor mode. The first refrigerant pump is turned on to assist in cooling. The speed of the first refrigerant pump is adjusted according to the pressure difference detected by the refrigerant pump inlet pressure sensor and the refrigerant pump outlet pressure sensor. The target pressure difference is 3 bar. When the pressure difference is lower than 3 bar, the speed of the first refrigerant pump is increased. When the pressure difference is higher than 3 bar, the speed of the first refrigerant pump is reduced. The unit also includes a second refrigerant pump set in parallel with the first refrigerant pump for redundancy design. When a failure is detected in the first refrigerant pump, the main control module automatically switches to the operation of the second refrigerant pump.

7. The control method for an evaporative condensing magnetic levitation multi-split air conditioning unit according to claim 4, characterized in that, When the outdoor temperature T satisfies T3 < T ≤ T2, T3 is taken as -10℃ and T2 is taken as 10℃, and the refrigerant pump operates in wet mode. The main control module opens the liquid circuit electric valve and the gas circuit electric valve and starts the first refrigerant pump. The refrigerant is delivered to the indoor terminal by the first refrigerant pump, and after passing through the dryer filter, sight glass, solenoid valve, and electronic expansion valve, it becomes a low-temperature, low-pressure gas-liquid mixture. It absorbs heat in the evaporator coil to become low-temperature, low-pressure vapor, and after passing through the suction dryer filter and the first one-way valve, it enters the evaporator condenser coil and releases heat to become low-temperature, low-pressure liquid. It then flows back to the first refrigerant pump through the liquid receiver to complete the natural cold source refrigeration. The first refrigerant pump adjusts its speed based on the pressure difference detected by the refrigerant pump inlet pressure sensor and the refrigerant pump outlet pressure sensor. The target pressure difference is 3.5 bar. When the pressure difference is lower than 3.5 bar, the speed is increased, and when it is higher than 3.5 bar, the speed is decreased. The evaporator-condenser fan adjusts its speed according to the cooling demand of the main unit using PID control. It starts when the cooling demand is >30%, runs at full speed when it is >100%, and when the cooling demand of a single terminal is >150%, the evaporator-condenser fan is forcibly accelerated to 130% of the current speed until the demand of that terminal is <100%, at which point the PID control is restored.

8. The control method for an evaporative condensing magnetic levitation multi-split air conditioning unit according to claim 4, characterized in that, When the outdoor temperature T satisfies T≤T3, and T3 is -10℃, the refrigerant pump operates in dry mode; the control methods of the refrigerant pump, indoor terminal, and evaporator-condenser fan are the same as those of the refrigerant pump in wet mode; the evaporator-condenser water pump is turned off, and only the evaporator-condenser fan is used to provide dry cooling heat dissipation for the evaporator-condenser coil, realizing energy-saving and water-saving natural cold source cooling.

9. The control method according to any one of claims 5-7, characterized in that, The evaporative condensate pump is switched on and off based on the outdoor temperature. It turns on when the outdoor temperature is >-10℃ and turns off otherwise. The electric heating of the water pan turns on when the water tank temperature sensor detects a temperature <2℃ to prevent the spray water from freezing. When the water quality tester detects that the water quality exceeds the limit, the main control module controls the drain solenoid valve and the inlet solenoid valve to open to realize automatic water replacement in the water tank.

10. The control method according to any one of claims 5-8, characterized in that, The air supply fan of each indoor terminal adjusts its speed according to the temperature difference between the supply and return air. The temperature difference threshold is 13℃. When the temperature difference is higher than 13℃, the speed is increased, and when it is lower than 13℃, the speed is decreased. The liquid circuit electric valve adjusts the refrigerant flow rate of the main pipeline according to the superheat of the intake air in the main pipeline. The electronic expansion valve of each terminal adjusts the branch flow rate according to its own target superheat.

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