Dual cold source air conditioning unit and control method

Abstract

The application discloses a double-cold-source air conditioning unit and a control method. The air conditioning unit comprises a natural cooling system, a three-way valve, a main control valve, a bypass channel, a bypass valve, a compressor refrigeration system, and a cooling unit. The natural cooling system comprises a cooling coil and the cooling unit arranged on a chilled water circulation loop. The chilled water circulation loop at the outlet end of the cooling coil is provided with the three-way valve and the main control valve. The first end of the three-way valve is connected with the outlet end of the cooling coil. The second end of the three-way valve is connected with the main control valve. The third end of the three-way valve is connected with the chilled water circulation loop at the inlet end of the cooling coil. The chilled water circulation loop is further provided with the bypass channel connected with the main control valve in parallel. The bypass channel is provided with the bypass valve. The compressor refrigeration system comprises a compressor, an evaporator, a condenser and a throttling element. The four components are connected to form a refrigerant circulation loop. The chilled water in the bypass channel exchanges heat with the refrigerant in the condenser to take away the heat of the refrigerant. The application solves the problems of low switching efficiency caused by manual switching and the inability to automatically switch between multiple working modes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of machine room air conditioning, in particular to a double-cold-source air conditioning unit and a control method. BACKGROUND

[0002] The double-cold-source air conditioning system usually adopts a parallel connection mode of a liquid cooling system and an air cooling system, and both systems can independently provide sufficient cooling capacity for the data center to ensure the refrigeration reliability of the double-cold-source air conditioning system.

[0003] In the process of implementing the present application, the inventors have found that the prior art at least has the following problems:

[0004] At present, the double-cold-source air conditioner has multiple working modes according to different outdoor working conditions and refrigeration requirements, but the switching mode between the multiple working modes is relatively cumbersome, and cannot realize quick and convenient switching according to different working conditions, resulting in that the existing double-cold-source air conditioner cannot fully utilize the natural cold source.

[0005] Therefore, in view of the above technical problems, how to realize quick and convenient switching between multiple working modes is a technical problem to be solved by those skilled in the art. SUMMARY

[0006] The purpose of the present application is to provide a double-cold-source air conditioning unit and a control method, to solve the problem of inconvenient switching between multiple working modes, and to achieve the purpose of fully utilizing the natural cold source.

[0007] To achieve the above-mentioned purpose, the present application provides a double-cold-source air conditioning unit, comprising:

[0008] A natural cooling system comprising a chilled water circulation loop, and a surface cooler coil and a cooling unit arranged on the chilled water circulation loop, a three-way valve and a main control valve are arranged on the chilled water circulation loop at the outlet end of the surface cooler coil, the first end of the three-way valve is connected with the outlet end of the surface cooler coil, the second end of the three-way valve is connected with the main control valve, the third end of the three-way valve is connected with the chilled water circulation loop at the inlet end of the surface cooler coil, a bypass channel is further arranged on the chilled water circulation loop in parallel with the main control valve, and a bypass valve is arranged on the bypass channel;

[0009] A compressor refrigeration system comprising a compressor, an evaporator, a condenser and a throttling element, the compressor, the evaporator, the condenser and the throttling element are connected to form a refrigerant circulation loop;

[0010] The chilled water in the bypass channel exchanges heat with the refrigerant in the condenser to take away the heat of the refrigerant.

[0011] Preferably, the condenser is a condensing coil, the condensing coil is provided with a first passage in communication with the bypass channel, and the condensing coil is further provided with a second passage in communication with the refrigerant circulation loop, and the first passage and the second passage are independently arranged.

[0012] Preferably, the evaporator is an evaporating coil, the evaporating coil is provided with a third passage in communication with the refrigerant circulation loop, and the evaporating coil is arranged in position corresponding to the cooling coil and is connected in series with the cooling coil in the air flow direction, so that the air return of the machine room passes through the cooling coil and the evaporating coil and is then sent to the machine room as air supply.

[0013] Preferably, the compressor refrigeration system is two groups, and the two groups of compressor refrigeration systems share one condensing coil and one evaporating coil, the number of the second passages in the condensing coil is two, and the two second passages are independently arranged, the number of the third passages in the evaporating coil is two, and the two third passages are crossed and independently arranged.

[0014] Preferably, the temperature detection system includes a plurality of temperature sensors, and the temperature detection system is used to detect the air supply temperature of the air conditioning unit, the inlet and outlet water temperatures of the cooling coil, and the air return temperature of the air conditioning unit.

[0015] A control method applied to the double-cold-source air conditioning unit, comprising:

[0016] determining the current operation mode of the air conditioning unit, the operation mode including: a compressor refrigeration mode, a pre-cooling mode, and a natural cooling mode;

[0017] when the compressor refrigeration mode is running, if the inlet water temperature of the cooling coil is less than or equal to the air return temperature of the machine room and lasts for a preset time, the first end and the second end of the three-way valve are controlled to be conductive, the main control valve is controlled to be off, the bypass valve is controlled to be conductive, and the compressor is controlled to run;

[0018] when the pre-cooling mode is running, if the inlet water temperature is less than or equal to the preset air supply temperature of the machine room and the compressor runs at a minimum frequency for a preset time, or if the actual air supply temperature of the machine room is less than the preset air supply temperature and the compressor runs at a minimum frequency for a preset time, the first end and the second end of the three-way valve are controlled to be conductive, the main control valve is controlled to be conductive, the bypass valve is controlled to be off, and the compressor is controlled to be off;

[0019] when the pre-cooling mode is running, if the inlet water temperature is greater than the air return temperature and lasts for a preset time, the second end and the third end of the three-way valve are controlled to be conductive, the main control valve is controlled to be off, the bypass valve is controlled to be conductive, and the compressor is controlled to run;

[0020] If the opening degree of the main control valve is greater than or equal to the preset opening degree, and the actual supply air temperature is greater than the preset supply air temperature, and the condition is maintained for a preset time, or if the water inlet temperature is greater than or equal to the preset supply air temperature and the condition is maintained for a preset time, the first end and the second end of the three-way valve are controlled to be conducted, the main control valve is controlled to be turned off, the bypass valve is controlled to be conducted, and the compressor is controlled to be operated.

[0021] Preferably, the step of determining the current operation mode of the air conditioning unit comprises:

[0022] When the air conditioning unit is started, if the water inlet temperature is greater than or equal to the preset return air temperature, the compressor refrigeration mode is started, and at this time the current operation mode is the compressor refrigeration mode; if the preset supply air temperature is less than the water inlet temperature and less than the preset return air temperature, the pre-cooling mode is started, and at this time the current operation mode is the pre-cooling mode; if the water inlet temperature is less than or equal to the preset supply air temperature, the natural cooling mode is started, and at this time the current operation mode is the natural cooling mode.

[0023] Preferably, the step of determining the current operation mode of the air conditioning unit further comprises:

[0024] During the operation of the air conditioning unit, the current operation mode of the air conditioning unit is determined based on the current states of the main control valve, the three-way valve, the bypass valve, and the compressor;

[0025] If the main control valve is turned off, the second end and the third end of the three-way valve are conducted, the bypass valve is conducted, and the compressor is operated, it is determined that the operation mode is the compressor refrigeration mode;

[0026] If the main control valve is turned off, the first end and the second end of the three-way valve are conducted, the bypass valve is conducted, and the compressor is operated, it is determined that the operation mode is the pre-cooling mode;

[0027] If the main control valve is conducted, the first end and the second end of the three-way valve are conducted, the bypass valve is turned off, and the compressor is turned off, it is determined that the operation mode is the natural cooling mode.

[0028] Preferably, when the pre-cooling mode is operated, the frequency of the compressor is adjusted according to the cooling capacity demand of the machine room, and the opening degree of the bypass valve is adjusted according to the temperature difference between the inlet and outlet water of the surface cooler coil.

[0029] Preferably, the step of controlling the first end and the second end of the three-way valve to be conducted, controlling the main control valve to be conducted, controlling the bypass valve to be turned off, and controlling the compressor to be turned off comprises:

[0030] The main control valve is controlled to open after a delay when the compressor is turned off, and the bypass valve is controlled to close in steps after the compressor is turned off and a preset time is delayed. After the main control valve is turned on, the opening degree of the main control valve is adjusted according to the actual air supply temperature.

[0031] Preferably, when the compressor is running in cooling mode, the compressor adjusts its frequency according to the cooling capacity requirement of the computer room, and the opening degree of the bypass valve is adjusted according to the temperature difference between the inlet and outlet water of the surface cooler coil.

[0032] Preferably, the steps of controlling the first and second ends of the three-way valve to be open, controlling the main control valve to be closed, controlling the bypass valve to be open, and controlling the compressor to operate include:

[0033] During the shut-off process of the main control valve, the opening degree of the bypass valve is adjusted based on the current opening degree of the main control valve and the temperature difference between the inlet and outlet water of the surface cooler coil. After the bypass valve is turned on, the compressor is controlled to run for a delay.

[0034] Compared with the prior art, the technical solution provided in this application has at least the following beneficial effects:

[0035] The air conditioning unit of this application can switch between different operating modes by changing the status of the main control valve, three-way valve, bypass valve, and compressor, which is convenient and quick. At the same time, it can also control the opening degree of the main control valve and bypass valve, as well as the operating frequency of the compressor, according to different outdoor temperatures and cooling needs, thereby making full use of natural cold sources and reducing the energy consumption of the compressor refrigeration system. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of a dual-cooling-source air conditioning unit provided in an embodiment of this application;

[0038] Figure 2 This is another schematic diagram of the dual-cooling-source air conditioning unit provided in the embodiments of this application.

[0039] In the diagram: 1-chilled water circulation loop; 2-cooler coil; 3-three-way valve; 4-main control valve; 5-bypass valve; 6-bypass channel; 7-refrigerant circulation loop; 8-condenser; 9-compressor; 10-throttling element; 11-evaporator; 12-temperature sensor. Detailed Implementation

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work are within the protection scope of the present application.

[0041] It should be noted that, in the present embodiment, the directions or positional relationships indicated by "upper", "lower", "front", "back" and the like are based on the directions or positional relationships shown in the drawings, and are merely for the convenience of describing the present application and simplifying the description, and thus cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus cannot be understood as limiting the present application. In addition, "first", "second", "third", "fourth" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0042] In order for those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0043] Please refer to Figure 1 In the present embodiment, a double-cold-source air conditioning unit is provided, which comprises a compressor refrigeration system, a natural cooling system, and a temperature detection system. The natural cooling system comprises a chilled water circulation loop 1 and a cooling coil 2 provided on the chilled water circulation loop 1. The chilled water circulation loop 1 is externally connected to a cooling unit, such as a cooling tower, etc., which can cool the chilled water by heat exchange with outdoor air. The cooled chilled water exchanges heat with room return air at the cooling coil 2.

[0044] A three-way valve 3 and a main control valve 4 are provided on the chilled water circulation loop 1 at the outlet end of the cooling coil 2. Please refer to Figure 1 The first end of the three-way valve 3 is connected to the outlet end of the cooling coil 2, the second end of the three-way valve 3 is connected to the main control valve 4, and the third end of the three-way valve 3 is connected to the chilled water circulation loop 1 at the inlet end of the cooling coil 2. It can be understood that the three-way valve 3 has three ports, two of which are kept open, and the other is kept closed.

[0045] The bypass passage 6 is provided in parallel with the main control valve 4, and the bypass valve 5 is provided in the bypass passage 6; wherein, by changing the state of the three-way valve 3, the flow path of the chilled water in the chilled water circulation loop 1 can be changed, for example, when the first end and the second end of the three-way valve 3 are connected, the chilled water can pass through the cooling coil 2, when the second end and the third end of the three-way valve 3 are connected, since the first end of the three-way valve 3 is closed, the chilled water does not pass through the cooling coil 2, but directly flows from the third end to the second end of the three-way valve 3, and flows to the main control valve 4. Similarly, by changing the state of the main control valve 4 and the bypass valve 5, the flow mode of the chilled water in the chilled water circulation loop 1 and the bypass passage 6 can also be changed, which will not be described here.

[0046] The compressor refrigeration system refers to that the refrigerant working medium, i.e. fluorine, becomes a high-pressure and high-temperature gas from the outlet of the compressor 9, enters the condenser 8, releases heat at the condenser 8, then passes through the expansion valve for pressure reduction, enters the evaporator 11 to exchange heat with the air return of the machine room, and then enters the compressor 9 to form a cycle. Specifically, the compressor refrigeration system includes the compressor 9, the evaporator 11, the condenser 8 and the throttling element 10, the compressor 9, the evaporator 11, the condenser 8 and the throttling element 10 are connected to form a refrigerant circulation loop 7, and the throttling element 10 can be an electronic expansion valve; the compressor refrigeration system also includes, for example, a suction pressure detector, a suction temperature detector, a condensing pressure detector and a condensing temperature detector, which can refer to the prior art.

[0047] Specifically, the air conditioning unit of the present application can be divided into a compressor refrigeration mode, a pre-cooling mode and a natural cooling mode according to the utilization of the natural cold source. The compressor refrigeration mode utilizes the cold produced by the compressor refrigeration system to exchange heat with the air return of the machine room, and after the refrigerant enters the condenser 8, it exchanges heat with the chilled water flowing through the condenser 8 and releases heat to reduce the condensing pressure of the condenser 8 and improve the refrigeration efficiency of the compressor refrigeration system. The pre-cooling mode utilizes the cold produced by the compressor refrigeration system and the natural cooling system to exchange heat with the air return of the machine room, the chilled water can pass through the cooling coil 2, and after the chilled water exchanges heat with the air return of the machine room at the cooling coil 2, it flows through the condenser 8 to exchange heat with the refrigerant in the condenser 8 and take away the heat.

[0048] The natural cooling mode utilizes the natural cooling system, and the chilled water only exchanges heat with the air return of the machine room at the cooling coil 2, and then returns to the cooling unit to form a cycle.

[0049] The temperature detection system comprises several temperature sensors 12, which can be arranged at the air supply side of the air conditioning unit, the water inlet side of the cooling coil 2, and the air return side of the air conditioning unit, so as to correspondingly detect the air supply temperature of the air conditioning unit, the water inlet temperature of the cooling coil 2, and the air return temperature of the air conditioning unit. Of course, pressure sensors can also be arranged at the water inlet and outlet sides of the cooling coil 2 according to actual conditions to detect the water pressure difference of the cooling coil 2.

[0050] The condenser 8 in the compressor refrigeration system can be a condensing coil, the condensing coil is provided with a first passage in communication with the bypass channel 6, and the condensing coil is also provided with a second passage in communication with the refrigerant circulation loop 7, and the first passage and the second passage are independently arranged; when the air conditioning unit is in the compressor refrigeration mode or the pre-cooling mode, the chilled water can enter the first passage through the bypass channel 6, and the refrigerant can enter the second passage through the refrigerant circulation loop 7, so that the chilled water and the refrigerant exchange heat at the condensing coil to cool the refrigerant.

[0051] The corresponding evaporator 11 can be an evaporating coil, the evaporating coil is provided with a third passage in communication with the refrigerant circulation loop 7, so that the refrigerant exchanges heat with the computer room air return in the evaporating coil. The evaporating coil corresponds to the position of the cooling coil 2 and is connected in series in the air flow direction, so that the computer room air return passes through the cooling coil 2 and the evaporating coil and then is supplied to the computer room.

[0052] In some embodiments, the cooling coil 2 and the evaporating coil are arranged in sequence in the air flow direction, that is, the cooling coil 2 is used as the air return side coil, and the evaporating coil is used as the air supply side coil; therefore, when the air conditioning unit operates in the compressor refrigeration mode and the pre-cooling mode, the air supply temperature is controlled by the evaporating coil, and when the air conditioning unit operates in the natural cooling mode, the air supply temperature is controlled by the cooling coil 2.

[0053] Please refer to Figure 2 The above compressor refrigeration system can be two groups, and the two groups of compressor refrigeration systems share one condensing coil and one evaporating coil, and the principle of each compressor refrigeration system is similar. The number of the second passages in the condensing coil is two, which correspond to two refrigerant circulation loops 7, and the two second passages are independently arranged; the number of the third passages in the evaporating coil is two, which can correspond to two refrigerant circulation systems, and the two third passages are crossed and independently arranged. The shared condensing coil and evaporating coil can reduce the additional space occupied by the two groups of compressor refrigeration systems in the computer room and improve the heat exchange effect.

[0054] In summary of the above embodiments, the air conditioning unit of the present application can switch among various working modes by changing the states of the main control valve 4, the three-way valve 3, the bypass valve 5 and the compressor 9, which is convenient and fast. Meanwhile, the opening degrees of the main control valve 4 and the bypass valve 5 and the operating frequency of the compressor 9 can be controlled according to different outdoor temperatures and cooling requirements, so as to fully utilize the natural cooling source and reduce the energy consumption of the compressor cooling system.

[0055] In the present embodiment, a control method is also provided, which can be applied to the above-mentioned dual cold source air conditioning unit, and the specific steps are as follows:

[0056] determining the current operating mode of the air conditioning unit, the operating mode including: a compressor cooling mode, a pre-cooling mode and a natural cooling mode;

[0057] when the compressor cooling mode is operated, if the water inlet temperature of the cooling coil 2 is less than or equal to the return air temperature of the machine room, it indicates that the cooling coil 2 has a certain heat exchange effect with the return air of the machine room and can provide a certain amount of cooling capacity, so after stable operation for a preset time (60s-600s), the first end and the second end of the three-way valve 3 are controlled to be conducted, the main control valve 4 is controlled to be turned off, the bypass valve 5 is controlled to be conducted, and the compressor 9 is controlled to be operated, so as to utilize the natural cooling system to provide a certain amount of cooling capacity, reduce the operating frequency of the compressor 9 and reduce the power consumption;

[0058] when the pre-cooling mode is operated, if the water inlet temperature of the cooling coil 2 is less than or equal to the preset supply air temperature of the machine room and the compressor 9 is operated at the minimum frequency for a preset time (60s-600s), it indicates that the compressor cooling system can provide less cooling capacity and the cooling capacity provided by the cooling coil 2 can meet the supply air temperature of the machine room, so the first end and the second end of the three-way valve 3 are controlled to be conducted, the main control valve 4 is controlled to be conducted, the bypass valve 5 is controlled to be turned off, and the compressor 9 is controlled to be turned off, so that the natural cooling system alone provides cooling capacity; or, when the pre-cooling mode is operated, if the actual supply air temperature of the machine room is less than the preset supply air temperature and the compressor 9 is operated at the minimum frequency for a preset time (0s-900s), it indicates that the cooling capacity provided by the cooling coil 2 can also meet the demand of the supply air temperature of the machine room under the condition that the compressor cooling system provides less cooling capacity, so the first end and the second end of the three-way valve 3 are controlled to be conducted, the main control valve 4 is controlled to be conducted, the bypass valve 5 is controlled to be turned off, and the compressor 9 is controlled to be turned off, so that the natural cooling system alone provides cooling capacity;

[0059] In addition, when the pre-cooling mode is running, if the water inlet temperature of the cooling coil 2 is greater than the return air temperature, and the condition lasts for a preset time (60s-600s), it indicates that the natural cooling system does not have the ability to provide cooling capacity at this time, so the second end and the third end of the three-way valve 3 are controlled to be conductive, the main control valve 4 is controlled to be off, the bypass valve 5 is controlled to be conductive, and the compressor 9 is controlled to run, so that the cooling capacity is provided by the compressor refrigeration system alone.

[0060] When the natural cooling mode is running, if the opening degree of the main control valve 4 is greater than or equal to a preset opening degree (90%-95%), and the actual supply air temperature is greater than a preset supply air temperature, and the condition lasts for a preset time (30s-300s), it indicates that the cooling capacity provided by the natural cooling system in the full-power running mode cannot meet the cooling capacity demand of the machine room at this time, so the first end and the second end of the three-way valve 3 are controlled to be conductive, the main control valve 4 is controlled to be off, the bypass valve 5 is controlled to be conductive, and the compressor 9 is controlled to run, so that the cooling capacity is provided by the natural cooling system and the compressor refrigeration system simultaneously; or, when the natural cooling mode is running, if the water inlet temperature of the cooling coil 2 is greater than or equal to the preset supply air temperature, and the condition lasts for a preset time (0s-600s), it indicates that the cooling coil 2 still has the ability to provide cooling capacity at this time, but the cooling capacity provided cannot meet the requirement of the preset supply air temperature, so the first end and the second end of the three-way valve 3 are controlled to be conductive, the main control valve 4 is controlled to be off, the bypass valve 5 is controlled to be conductive, and the compressor 9 is controlled to run, so that the cooling capacity is provided by the natural cooling system and the compressor refrigeration system simultaneously.

[0061] In summary of the above embodiments, the air conditioning unit of the present application can adjust the running mode by changing the states of the main control valve 4, the three-way valve 3, the bypass valve 5, and the compressor 9, the running mode including the compressor refrigeration mode, the pre-cooling mode, and the natural cooling mode, the compressor refrigeration mode using the compressor refrigeration system alone to provide cooling capacity, the chilled water being exchanged with the refrigerant; the pre-cooling mode using the compressor refrigeration system and the natural cooling system to provide cooling capacity simultaneously, the chilled water being exchanged with the refrigerant; and the natural cooling mode using the natural cooling system alone to provide cooling capacity, the chilled water not being exchanged with the refrigerant. At the same time, the air conditioning unit of the present application also follows the switching principles of the compressor refrigeration mode to the pre-cooling mode, the pre-cooling mode to the natural cooling mode, the natural cooling mode to the pre-cooling mode, and the pre-cooling mode to the compressor refrigeration mode when switching modes, avoiding direct switching from the natural cooling mode to the compressor refrigeration mode, and preventing the problems of sudden temperature rise and sudden temperature drop in the machine room.

[0062] It should be noted that determining the current running mode of the air conditioning unit also includes determining the running mode of the air conditioning unit when the air conditioning is started, and determining the running mode of the air conditioning unit during running; specifically, the step of determining the running mode when the air conditioning unit is started includes:

[0063] When the air conditioning unit starts, if the water inlet temperature of the cooling coil 2 is greater than or equal to the preset return air temperature, it indicates that the natural cooling system does not have the ability to provide cold at this time, so the cold is provided by the compressor refrigeration system alone, and the corresponding compressor refrigeration mode should be started. At this time, the current operation mode is the compressor refrigeration mode; if the preset supply air temperature is less than the water inlet temperature of the cooling coil 2 and less than the preset return air temperature, it indicates that the natural cooling system has the ability to exchange heat with the return air of the machine room, that is, it can provide a certain amount of cold, but because the water inlet temperature of the cooling coil 2 is greater than the preset supply air temperature, the cold provided by the natural cooling system cannot meet the supply air temperature requirement of the machine room, so the natural cooling system and the compressor refrigeration system need to provide cold at the same time to start in the pre-cooling mode. At this time, the current operation mode is the pre-cooling mode; if the water inlet temperature of the cooling coil 2 is less than or equal to the preset supply air temperature, it indicates that the cold provided by the natural cooling system can meet the cold demand of the machine room, so the cold can be provided by the natural cooling system alone to start in the natural cooling mode. At this time, the current operation mode is the natural cooling mode.

[0064] And the step of determining the operation mode of the air conditioning unit during operation also includes:

[0065] During the operation of the air conditioning unit, because the return air temperature, the supply air temperature, the water inlet temperature of the cooling coil 2 and the like will change according to different working conditions, it is difficult and inaccurate to determine the operation mode by using the above conditions, so the current operation mode of the air conditioning unit can be determined based on the state of the main control valve 4, the three-way valve 3, the bypass valve 5 and the compressor 9;

[0066] If the main control valve 4 is closed, the second end and the third end of the three-way valve 3 are conducted, the bypass valve 5 is conducted, and the compressor 9 is running, it is determined that the operation mode is the compressor refrigeration mode;

[0067] If the main control valve 4 is closed, the first end and the second end of the three-way valve 3 are conducted, the bypass valve 5 is conducted, and the compressor 9 is running, it is determined that the operation mode is the pre-cooling mode;

[0068] If the main control valve 4 is conducted, the first end and the second end of the three-way valve 3 are conducted, the bypass valve 5 is closed, and the compressor 9 is closed, it is determined that the operation mode is the natural cooling mode;

[0069] Correspondingly, when the air conditioning unit corresponds to the above different modes, the state of the main control valve 4, the three-way valve 3, the bypass valve 5 and the state of the compressor 9 should also be maintained accordingly.

[0070] The purpose of determining the current operation state of the air conditioning unit is to accurately determine the judgment condition when switching other modes, so as to ensure that the air conditioning unit has a more accurate control logic.

[0071] On the basis of the above, when switching from running the compressor refrigeration mode to running the pre-cooling mode, specifically including:

[0072] The second end and the third end of the three-way valve 3 are gradually adjusted to be conductive to the first end and the second end, the main control valve 4 remains off, the bypass valve 5 remains conductive, and the compressor 9 remains running, so as to run the pre-cooling mode, and when running the pre-cooling mode, the compressor 9 adjusts the frequency according to the cooling capacity demand of the machine room, and the opening of the bypass valve 5 is adjusted according to the PID of the temperature difference between the inlet and outlet water of the cooler coil 2.

[0073] When switching from running the pre-cooling mode to running the natural cooling mode, specifically including:

[0074] The compressor 9 is controlled to be closed, the main control valve 4 is controlled to be conductive after the compressor 9 is closed for a preset time (0s-300s), the bypass valve 5 is controlled to be step-off after the compressor 9 is closed for a preset time (0s-300s), and the first end and the second end of the three-way valve 3 remain conductive, so as to run the natural cooling mode, and when running the natural cooling mode, the opening of the main control valve 4 is adjusted according to the actual supply air temperature. After the compressor 9 is closed for a preset time, the main control valve 4 is controlled to be conductive and the bypass valve 5 is controlled to be off, that is, after the compressor 9 is closed, the natural cooling mode is switched, so as to avoid the influence of the compressor 9 on the running of the natural cooling mode;

[0075] At the same time, during the switching process from the pre-cooling mode to the natural cooling mode, the opening of the main control valve 4 should be adjusted based on the temperature difference between the inlet and outlet water of the cooler coil 2, so as to adjust the heat exchange capacity of the cooler coil 2; that is, if the temperature difference between the inlet and outlet water of the cooler coil 2 is too small, the opening of the main control valve 4 is increased, and the flow through the cooler coil 2 is increased; if the temperature difference between the inlet and outlet water of the cooler coil 2 is too large, the opening of the main control valve 4 is reduced, and the flow through the cooler coil 2 is reduced, so as to maintain the cooling capacity provided by the cooler coil 2 and the cooling capacity required by the machine room in a substantially consistent range.

[0076] When switching from running the pre-cooling mode to running the compressor refrigeration mode, specifically including:

[0077] The first end and the second end of the three-way valve 3 are gradually adjusted to be conductive to the second end and the third end, the main control valve 4 remains off, the bypass valve 5 remains conductive, and the compressor 9 remains running, so as to run the compressor refrigeration mode, and when running the compressor refrigeration mode, the compressor 9 adjusts the frequency according to the cooling capacity demand of the machine room, and the opening of the bypass valve 5 is adjusted according to the temperature difference between the inlet and outlet water of the cooler coil 2.

[0078] When switching from running the natural cooling mode to running the pre-cooling mode, specifically including:

[0079] The main control valve 4 is controlled to be closed, the bypass valve 5 is controlled to be turned on, and during the process of closing the main control valve 4, the opening degree of the bypass valve 5 is adjusted based on the current opening degree of the main control valve 4 and the temperature difference between the inlet and outlet water of the radiator coil 2, specifically, the opening degree of the bypass valve 5 is the current opening degree of the main control valve 4 + a set opening degree value, and the set opening degree value is determined based on the temperature difference between the inlet and outlet water of the radiator coil 2; adjusting the opening degree of the bypass valve 5 based on the current opening degree of the main control valve 4 and the temperature difference between the inlet and outlet water of the radiator coil 2 can adjust the flow of chilled water flowing into the condenser 8, so as to maintain that the refrigerant can release enough heat. After the bypass valve 5 is turned on, the compressor 9 is controlled to run for a delay (0s-120s), and the first end and the second end of the three-way valve 3 are kept turned on to run the pre-cooling mode. During the pre-cooling mode, the frequency of the compressor 9 is adjusted according to the cooling capacity demand of the machine room, and the opening degree of the bypass valve 5 is adjusted according to the temperature difference between the inlet and outlet water of the radiator coil 2.

[0080] It should be noted that the above-mentioned preset time, preset supply air temperature and preset return air temperature are manually set, which can be obtained through multiple tests according to actual working conditions, including but not limited to the above-mentioned parameters, all of which fall within the protection scope of the present application.

[0081] It should be noted that in the present specification, the relationship terms such as first and second are only used to distinguish one entity from another, and do not necessarily require or imply any such actual relationship or order between the entities.

[0082] The principles and implementation modes of the present application are described by using specific examples in the present specification, and the above-mentioned examples are only used to help understand the method and its core idea of the present application. It should be noted that for ordinary skilled in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the present application.

Claims

1. A control method, characterized in that, Applied to dual-source air conditioning units, the dual-source air conditioning unit includes: The natural cooling system includes a chilled water circulation loop (1) and a surface cooler coil (2) and a cooling unit installed on the chilled water circulation loop (1). A three-way valve (3) and a main control valve (4) are provided on the chilled water circulation loop (1) at the liquid outlet end of the surface cooler coil (2). The first end of the three-way valve (3) is connected to the liquid outlet end of the surface cooler coil (2), the second end of the three-way valve (3) is connected to the main control valve (4), and the third end of the three-way valve (3) is connected to the chilled water circulation loop (1) at the liquid inlet end of the surface cooler coil (2). A bypass channel (6) connected in parallel with the main control valve (4) is also provided on the chilled water circulation loop (1), and a bypass valve (5) is provided on the bypass channel (6). The compressor refrigeration system includes a compressor (9), an evaporator (11), a condenser (8), and a throttling element (10). The compressor (9), the evaporator (11), the condenser (8), and the throttling element (10) are connected to form a refrigerant circulation loop (7). The chilled water in the bypass channel (6) exchanges heat with the refrigerant in the condenser (8) to remove the heat from the refrigerant. The control method includes: determining the current operating mode of the air conditioning unit, wherein the operating mode includes: compressor cooling mode, pre-cooling mode, and natural cooling mode; When the compressor is running in cooling mode, if the inlet water temperature of the surface cooler coil (2) is less than or equal to the return air temperature of the machine room and continues for a preset time, the pre-cooling mode is run, the first and second ends of the three-way valve (3) are opened, the main control valve (4) is closed, the bypass valve (5) is opened, and the compressor (9) is run. When the precooling mode is running, if the inlet water temperature is less than or equal to the preset air supply temperature of the machine room, and the compressor (9) runs at the minimum frequency for a preset time, or if the actual air supply temperature of the machine room is less than the preset air supply temperature, and the compressor (9) runs at the minimum frequency for a preset time, then the first and second ends of the three-way valve (3) are controlled to open, the main control valve (4) is controlled to open, the bypass valve (5) is controlled to close, and the compressor (9) is controlled to close. When the precooling mode is running, if the inlet water temperature is greater than the return air temperature and continues for a preset time, the second and third ends of the three-way valve (3) are opened, the main control valve (4) is closed, the bypass valve (5) is opened, and the compressor (9) is run. When the natural cooling mode is running, if the opening of the main control valve (4) is greater than or equal to the preset opening, and the actual air supply temperature is greater than the preset air supply temperature and continues for a preset time, or if the inlet water temperature is greater than or equal to the preset air supply temperature and continues for a preset time, then the first and second ends of the three-way valve (3) are controlled to open, the main control valve (4) is controlled to close, the bypass valve (5) is controlled to open, and the compressor (9) is controlled to run.

2. The control method according to claim 1, characterized in that, The condenser (8) is a condenser plate heat exchanger. The condenser plate heat exchanger is provided with a first passage that communicates with the bypass passage (6). The condenser plate heat exchanger is also provided with a second passage that communicates with the refrigerant circulation loop (7). The first passage and the second passage are set independently.

3. The control method according to claim 2, characterized in that, The evaporator (11) is an evaporator coil. The evaporator coil has a third passage that is connected to the refrigerant circulation loop (7). The evaporator coil and the surface cooler coil (2) are positioned corresponding to each other and connected in series in the airflow direction so that the return air of the machine room passes through the surface cooler coil (2) and the evaporator coil and is then sent into the machine room.

4. The control method according to claim 3, characterized in that, The compressor refrigeration system consists of two sets, which share one condenser heat exchanger and one evaporator coil. The condenser heat exchanger has two second passages, which are independently configured. The evaporator coil has two third passages, which are intersecting and independently configured.

5. The control method according to any one of claims 1-4, characterized in that, The dual-source air conditioning unit also includes a temperature detection system, which includes several temperature sensors (12). The temperature detection system is used to detect the supply air temperature of the air conditioning unit, the inlet and outlet water temperatures of the surface cooler coil (2), and the return air temperature of the air conditioning unit.

6. The control method according to claim 1, characterized in that, The step of determining the current operating mode of the air conditioning unit includes: When the air conditioning unit starts, if the inlet water temperature is greater than or equal to the preset return air temperature, it starts in the compressor cooling mode, and the current operating mode is the compressor cooling mode; if the preset supply air temperature is less than the inlet water temperature and less than the preset return air temperature, it starts in the pre-cooling mode, and the current operating mode is the pre-cooling mode; if the inlet water temperature is less than or equal to the preset supply air temperature, it starts in the natural cooling mode, and the current operating mode is the natural cooling mode. During the operation of the air conditioning unit, the current operating mode of the air conditioning unit is determined based on the current status of the main control valve (4), the three-way valve (3), the bypass valve (5) and the compressor (9); If the main control valve (4) is closed, the second and third ends of the three-way valve (3) are open, the bypass valve (5) is open, and the compressor (9) is running, then the operating mode is determined to be the compressor refrigeration mode; If the main control valve (4) is closed, the first and second ends of the three-way valve (3) are open, the bypass valve (5) is open, and the compressor (9) is running, then the operating mode is determined to be the pre-cooling mode; If the main control valve (4) is open, the first and second ends of the three-way valve (3) are open, the bypass valve (5) is closed, and the compressor (9) is shut down, then the operating mode is determined to be the natural cooling mode.

7. The control method according to claim 6, characterized in that, When the precooling mode is running, the compressor (9) adjusts the frequency according to the cooling demand of the machine room, and the opening of the bypass valve (5) is adjusted according to the temperature difference between the inlet and outlet water of the surface cooler coil (2). When the compressor is running in cooling mode, the compressor (9) adjusts its frequency according to the cooling demand of the computer room, and the opening of the bypass valve (5) is adjusted according to the temperature difference between the inlet and outlet water of the surface cooler coil (2).

8. The control method according to claim 6, characterized in that, The steps of controlling the first and second ends of the three-way valve (3) to be open, controlling the main control valve (4) to be open, controlling the bypass valve (5) to be closed, and controlling the compressor (9) to be shut down include: The main control valve (4) is controlled to turn on after a delay after the compressor (9) is turned off, and the bypass valve (5) is controlled to turn off step by step after the compressor (9) is turned off and a preset time is delayed. After the main control valve (4) is turned on, the opening degree of the main control valve (4) is adjusted according to the actual air supply temperature.

9. The control method according to claim 6, characterized in that, The steps of controlling the first and second ends of the three-way valve (3) to open, controlling the main control valve (4) to close, controlling the bypass valve (5) to open, and controlling the operation of the compressor (9) include: During the shut-off process of the main control valve (4), the opening degree of the bypass valve (5) is adjusted based on the current opening degree of the main control valve (4) and the temperature difference between the inlet and outlet water of the surface cooler coil (2). After the bypass valve (5) is turned on, the compressor (9) is controlled to run for a delay.

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