Double-cold-source air conditioning unit and control method

Abstract

The invention discloses a double-cold-source air conditioning unit and a control method, the air conditioning unit comprises a natural cooling system, the natural cooling system comprises a surface air cooler coil and a cooling unit which are arranged on a chilled water circulation loop, the chilled water circulation loop at the liquid outlet end of the surface air cooler coil is provided with a three-way valve and a main control valve, the first end of the three-way valve is connected with the liquid outlet end of the surface air cooler coil, and the second end of the three-way valve is connected with the liquid outlet end of the cooling unit; 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 a chilled water circulation loop at the liquid inlet end of the surface air cooler coil, a bypass channel connected with the main control valve in parallel is further arranged on the chilled water circulation loop, and a bypass valve is arranged on the bypass channel; the compressor refrigerating system comprises a compressor, an evaporator, a condenser and a throttling element which are connected to form a refrigerant circulation loop; and the chilled water in the bypass channel exchanges heat with the refrigerant in the condenser, so that the heat of the refrigerant is taken away. The problems that the switching efficiency is low due to manual switching, and multiple working modes cannot be stably and automatically switched are solved.

Description

Technical Field

[0001] The present application relates to the technical field of computer room air conditioning, and in particular to a dual-cold-source air conditioning unit and a control method thereof. Background Art

[0002] The dual-cold-source air-conditioning system usually adopts a liquid cooling system and an air cooling system in parallel. Both systems can independently provide sufficient cooling capacity for the data center to ensure the cooling reliability of the dual-cold-source air-conditioning system.

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

[0004] At present, dual-cold source air conditioners have multiple working modes according to different outdoor working conditions and cooling needs, but the switching method between the multiple working modes is relatively cumbersome, and it is impossible to achieve fast and convenient switching according to different working conditions, resulting in the existing dual-cold source air conditioners being unable to fully utilize the outdoor natural cold source.

[0005] Therefore, in response to the above technical problems, how to achieve fast and convenient switching between multiple working modes is a technical problem that technical personnel in this field need to solve. Summary of the invention

[0006] The purpose of the present application is to provide a dual-cold source air-conditioning unit and a control method to solve the problem of inconvenience in switching between multiple working modes, thereby achieving the purpose of making full use of natural cold sources.

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

[0008] The natural cooling system comprises a chilled water circulation loop, a condenser 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 liquid outlet end of the condenser coil, a first end of the three-way valve is connected to the liquid outlet end of the condenser coil, a second end of the three-way valve is connected to the main control valve, a third end of the three-way valve is connected to the chilled water circulation loop at the liquid inlet end of the condenser coil, a bypass channel connected in parallel with the main control valve is also arranged on the chilled water circulation loop, 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, wherein 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 condensation plate exchanger, a first passage communicating with the bypass channel is provided in the condensation plate exchanger, a second passage communicating with the refrigerant circulation circuit is also provided in the condensation plate exchanger, and the first passage and the second passage are independently arranged.

[0012] Preferably, the evaporator is an evaporating coil, and a third passage connected to the refrigerant circulation circuit is provided in the evaporating coil. The evaporating coil corresponds to the position of the condenser coil and is connected in series in the air flow direction so that the return air from the machine room passes through the condenser coil and the evaporating coil and then is delivered to the machine room.

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

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

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

[0016] Determine the current operation mode of the air conditioning unit, the operation mode including: compressor cooling mode, precooling mode, and natural cooling mode;

[0017] When the compressor is running in cooling mode, if the water inlet temperature of the condenser coil is less than or equal to the return air 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 connected, the main control valve is controlled to be closed, the bypass valve is controlled to be connected, and the compressor is controlled to run;

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

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

[0020] When running the natural cooling mode, if the opening of the main control valve is greater than or equal to the preset opening, and the actual supply air temperature is greater than the preset supply air temperature and lasts for a preset time, or if the inlet water temperature is greater than or equal to the preset supply air temperature and lasts for a preset time, the first end and the second end of the three-way valve are controlled to be connected, the main control valve is controlled to be closed, the bypass valve is controlled to be connected, and the compressor is controlled to operate.

[0021] Preferably, the step of determining the current operating 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, it is started 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 water inlet temperature and less than the preset return air temperature, it is started in the pre-cooling mode, and the current operating mode is the pre-cooling mode; if the water inlet temperature is less than or equal to the preset supply air temperature, it is started in the natural cooling mode, and the current operating mode is the natural cooling mode.

[0023] Preferably, the step of determining the current operating mode of the air-conditioning unit further includes:

[0024] During the operation of the air conditioning unit, determining the current operation mode of the air conditioning unit 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 off, the second end and the third end of the three-way valve are connected, the bypass valve is connected, and the compressor is running, then the operating mode is determined to be the compressor cooling mode;

[0026] If the main control valve is turned off, the first end and the second end of the three-way valve are connected, the bypass valve is turned on, and the compressor is running, then the operating mode is determined to be the pre-cooling mode;

[0027] If the main control valve is turned on, the first end and the second end of the three-way valve are turned on, 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 compressor adjusts the frequency according to the cooling demand of the machine room, and the opening of the bypass valve is adjusted according to the inlet and outlet water temperature difference of the condenser coil.

[0029] Preferably, the steps of controlling the first end and the second end of the three-way valve to be conductive, controlling the main control valve to be conductive, controlling the bypass valve to be closed, and controlling the compressor to be shut down include:

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

[0031] Preferably, when the compressor cooling mode is operated, the compressor adjusts the frequency according to the cooling demand of the machine room, and the opening of the bypass valve is adjusted according to the inlet and outlet water temperature difference of the condenser coil.

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

[0033] During the closing process of the main control valve, the opening of the bypass valve is adjusted based on the current opening of the main control valve and the inlet and outlet water temperature difference of the condenser coil, and the compressor is controlled to delay operation after the bypass valve is turned on.

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

[0035] When the air-conditioning unit of the present application switches between multiple working modes, the switching between different modes can be realized by changing the states of the main control valve, the three-way valve, the bypass valve and the compressor, which is convenient and quick. At the same time, the opening of the main control valve and the bypass valve can be controlled according to different outdoor temperatures and cooling requirements, as well as the operating frequency of the compressor, so as to make full use of the natural cold source and reduce the energy consumption of the compressor refrigeration system. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0037] FIG1 is a schematic diagram of a principle of a dual cold source air conditioning unit provided in an embodiment of the present application;

[0038] FIG. 2 is another schematic diagram of the principle of the dual-cold-source air-conditioning unit provided in an embodiment of the present application.

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

[0040] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0041] It should be noted that in this embodiment, the directions or positional relationships indicated by "upper", "lower", "front", "back", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present application. In addition, "first", "second", "third", and "fourth" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0042] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0043] Please refer to Figure 1. In this embodiment, a dual-cold source air-conditioning unit is provided, which includes a compressor refrigeration system, a natural cooling system, and a temperature detection system; the natural cooling system includes a chilled water circulation loop 1 and a surface cooler coil 2 arranged 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, which can cool the chilled water by exchanging heat with the outdoors. The cooled chilled water exchanges heat with the return air from the machine room at the surface cooler 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 liquid outlet end of the condenser coil 2. Referring to FIG1 , the first end of the three-way valve 3 is connected to the liquid outlet end of the condenser 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 condenser coil 2. It can be understood that the three-way valve 3 has three ports, two of which remain open and the other port remains closed.

[0045] A bypass channel 6 connected in parallel with the main control valve 4 is also provided in the chilled water circulation loop 1, and a bypass valve 5 is provided on the bypass channel 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 surface cooler coil 2, and 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 surface cooler coil 2, but flows directly from the third end of the three-way valve 3 to the second end, and flows toward 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 channel 6 can also be changed, which will not be repeated here.

[0046] The compressor refrigeration system means that the refrigerant, i.e., fluorine, is converted into a high-pressure and high-temperature gas from the outlet of the compressor 9 and enters the condenser 8, where it releases heat, and then enters the evaporator 11 through throttling and pressure reduction by the expansion valve to exchange heat with the return air in the machine room, and then enters the compressor 9 to form a cycle. Specifically, 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 throttling element 10 can be an electronic expansion valve; the compressor refrigeration system also includes a suction pressure detector, a suction temperature detector, a condensation pressure detector, and a condensation temperature detector, etc., and reference can be made to the prior art.

[0047] Among them, the chilled water in the bypass channel 6 can also exchange heat with the refrigerant in the condenser 8, thereby taking away the heat of the refrigerant; specifically, the air-conditioning unit of the present application can be divided into a compressor cooling mode, a pre-cooling mode, and a natural cooling mode according to the utilization of the natural cold source. The compressor cooling mode uses the cold energy generated by the compressor refrigeration system to exchange heat with the return air of the machine room. At the same time, after the refrigerant enters the condenser 8, it exchanges heat with the chilled water flowing through the condenser 8 and releases heat, so as to reduce the condensation pressure of the condenser 8 and improve the refrigeration efficiency of the compressor refrigeration system; the pre-cooling mode uses the cold energy generated by the compressor refrigeration system and the natural cooling system to exchange heat with the return air of the machine room. The chilled water can pass through the surface cooler coil 2. At the same time, after the chilled water exchanges heat with the return air of the machine room at the surface cooler coil 2, it will also flow through the condenser 8, thereby exchanging heat with the refrigerant in the condenser 8 and taking away heat.

[0048] The natural cooling mode utilizes the natural cooling system. The chilled water only passes through the surface cooler coil 2 to exchange heat with the return air from the computer room, and then flows back to the cooling unit after heat exchange, forming a cycle.

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

[0050] Among them, the condenser 8 in the compressor refrigeration system can be a condensation plate exchanger, and a first passage connected to the bypass channel 6 is provided in the condensation plate exchanger, and a second passage connected to the refrigerant circulation loop 7 is also provided in the condensation plate exchanger, 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 condensation plate exchanger to cool the refrigerant.

[0051] The corresponding evaporator 11 can be an evaporating coil, and a third passage connected to the refrigerant circulation circuit 7 is provided in the evaporating coil, so that the refrigerant exchanges heat with the return air from the machine room in the evaporating coil. The evaporating coil corresponds to the position of the surface cooler coil 2 and is connected in series in the airflow direction, so that the return air from the machine room passes through the surface cooler coil 2 and the evaporating coil and then is delivered to the machine room.

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

[0053] Please refer to Figure 2. The above compressor refrigeration system can be two groups. The two groups of compressor refrigeration systems share one condensing plate and one evaporating coil. The principle of each compressor refrigeration system is similar. The number of second passages in the condensing plate is two, corresponding to two refrigerant circulation loops 7, and the two second passages are independently set; the number of third passages in the evaporating plate is two, which can correspond to two refrigerant circulation systems, and the two third passages are crossed and independently set. The setting method of sharing one condensing plate and one evaporating coil can reduce the extra machine room space occupied by the two groups of compressor refrigeration systems, while improving the heat exchange effect.

[0054] In summary of the above embodiments, when the air-conditioning unit of the present application switches between multiple working modes, the switching between different modes can be realized 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 quick. At the same time, the opening of the main control valve 4 and the bypass valve 5 can be controlled according to different outdoor temperatures and cooling requirements, as well as the operating frequency of the compressor 9, so as to make full use of the natural cold source and reduce the energy consumption of the compressor refrigeration system.

[0055] In this 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] Determine the current operation mode of the air conditioning unit, the operation modes include: compressor cooling mode, precooling mode, and natural cooling mode;

[0057] When the compressor cooling mode is running, if the water inlet temperature of the surface cooler coil 2 is less than or equal to the return air temperature of the machine room, it means that the surface cooler coil 2 and the return air of the machine room have a certain heat exchange effect at this time, and the surface cooler coil 2 can provide a certain amount of cooling capacity. Therefore, after the preset stable operation time (60s-600s), the first end and the second end of the three-way valve 3 are controlled to be connected, the main control valve 4 is controlled to be closed, the bypass valve 5 is controlled to be connected, and the compressor 9 is controlled to run, so as to use the natural cooling system to provide a certain amount of cooling capacity, reduce the operating frequency of the compressor 9, and reduce power consumption;

[0058] When the pre-cooling mode is in operation, if the inlet water temperature of the surface cooler coil 2 is less than or equal to the preset supply air temperature of the machine room, and the compressor 9 runs at the minimum frequency for a preset time (60s-600s), it means that the compressor refrigeration system can provide less cooling capacity at this time, and the cooling capacity provided by the surface cooler coil 2 can meet the supply air temperature of the machine room. Therefore, the first end and the second end of the three-way valve 3 can be controlled to be connected, the main control valve 4 can be controlled to be connected, the bypass valve 5 can be controlled to be closed, and the compressor 9 can be controlled to be turned off, and the cooling capacity is provided by the natural cooling system alone; or, when the pre-cooling mode is in operation, if the actual supply air temperature of the machine room is less than the preset supply air temperature, and the compressor 9 runs at the minimum frequency for a preset time (0s-900s), it means that when the compressor refrigeration system provides less cooling capacity, the cooling capacity provided by the surface cooler coil 2 can also meet the demand of the supply air temperature of the machine room. Therefore, the first end and the second end of the three-way valve 3 can be controlled to be connected, the main control valve 4 can be controlled to be connected, the bypass valve 5 can be controlled to be closed, and the compressor 9 can be controlled to be turned off, and the cooling capacity is provided by the natural cooling system alone;

[0059] In addition, when running in the pre-cooling mode, if the inlet water temperature of the surface cooler coil 2 is greater than the return air temperature and lasts for a preset time (60s-600s), it means that the natural cooling system is not capable of providing cooling capacity at this time, so the second and third ends of the three-way valve 3 can be controlled to be connected, the main control valve 4 can be controlled to be closed, the bypass valve 5 can be controlled to be connected, and the compressor 9 can be controlled to run, so that the compressor refrigeration system can provide cooling capacity alone;

[0060] 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 (90%-95%), and the actual supply air temperature is greater than the preset supply air temperature, and lasts for a preset time (30s-300s), it means that the natural cooling system is in full power operation mode at this time, and the cooling capacity provided is still unable to meet the cooling capacity demand of the computer room. Therefore, the first end and the second end of the three-way valve 3 can be controlled to be connected, the main control valve 4 can be controlled to be closed, the bypass valve 5 can be controlled to be connected, and the compressor 9 can be controlled to run, and the natural cooling system and the compressor refrigeration system can provide cooling capacity at the same time; or, when the natural cooling mode is running, if the inlet water temperature of the surface cooler coil 2 is greater than or equal to the preset supply air temperature, and lasts for a preset time (0s-600s), it means that the surface cooler coil 2 may still have the ability to provide cooling capacity, but the cooling capacity provided can no longer meet the requirement of the preset supply air temperature. Therefore, the first end and the second end of the three-way valve 3 can be controlled to be connected, the main control valve 4 can be controlled to be closed, the bypass valve 5 can be controlled to be connected, and the compressor 9 can be controlled to run, and the natural cooling system and the compressor refrigeration system can provide cooling capacity at the same time.

[0061] In summary of the above embodiments, the air-conditioning unit of the present application can adjust the operation mode by changing the state of the main control valve 4, the three-way valve 3, the bypass valve 5 and the compressor 9. The operation modes include compressor refrigeration mode, pre-cooling mode and natural cooling mode. The compressor refrigeration mode uses the compressor refrigeration system alone to provide cooling capacity, and the chilled water exchanges heat with the refrigerant; the pre-cooling mode uses both the compressor refrigeration system and the natural cooling system to provide cooling capacity, and the chilled water exchanges heat with the refrigerant; the natural cooling mode uses the natural cooling system alone to provide cooling capacity, and the chilled water does not exchange heat with the refrigerant. At the same time, when the air-conditioning unit of the present application switches modes, it also follows the switching principles from compressor refrigeration mode to pre-cooling mode, pre-cooling mode to natural cooling mode, natural cooling mode to pre-cooling mode, and pre-cooling mode to compressor refrigeration mode, so as to avoid direct switching from natural cooling mode to compressor refrigeration mode, and prevent the problem of sudden temperature rise and drop in the machine room.

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

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

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

[0065] During the operation of the air conditioning unit, since the return air temperature, the supply air temperature, the water inlet temperature of the surface cooler coil 2, etc. will change according to different working conditions, it is difficult and inaccurate to determine the operation mode using the above conditions. Therefore, the current operation mode of the air conditioning unit can be determined based on the current 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 off, the second end and the third end of the three-way valve 3 are connected, the bypass valve 5 is connected, and the compressor 9 is running, then the operating mode is determined to be the compressor cooling mode;

[0067] If the main control valve 4 is off, the first end and the second end of the three-way valve 3 are connected, the bypass valve 5 is connected, and the compressor 9 is running, then the operation mode is determined to be the pre-cooling mode;

[0068] If the main control valve 4 is turned on, the first end and the second end of the three-way valve 3 are turned on, the bypass valve 5 is turned off, and the compressor 9 is turned off, then the operation mode is determined to be the natural cooling mode;

[0069] Correspondingly, when the air-conditioning unit operates in the above-mentioned different modes, the states of the above-mentioned main control valve 4, the three-way valve 3, the bypass valve 5 and the state of the compressor 9 should also remain corresponding.

[0070] The purpose of determining the current operating state of the air-conditioning unit is to accurately determine the judgment conditions when switching to other modes, thereby ensuring that the air-conditioning unit has a more accurate control logic.

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

[0072] The second and third ends of the three-way valve 3 are controlled to be gradually adjusted to be connected to the first and second ends, the main control valve 4 remains closed, the bypass valve 5 remains turned on, and the compressor 9 remains running to run the pre-cooling mode. When running in the pre-cooling mode, the compressor 9 adjusts the frequency according to the cooling demand of the machine room, and the opening of the bypass valve 5 is PID-adjusted according to the inlet and outlet water temperature difference of the surface cooler coil 2.

[0073] When switching from pre-cooling mode to natural cooling mode, it specifically includes:

[0074] Control the compressor 9 to shut down, control the main control valve 4 to conduct after the compressor 9 is shut down for a preset time (0s-300s), control the bypass valve 5 to step-close after the compressor 9 is shut down and the preset time (0s-300s), and keep the first end and the second end of the three-way valve 3 turned on to run the natural cooling mode. When the natural cooling mode is running, the opening of the main control valve 4 is adjusted according to the actual air supply temperature. After the compressor 9 is shut down and the preset time is delayed, the main control valve 4 is controlled to conduct and the bypass valve 5 is controlled to close, that is, the natural cooling mode is switched after the compressor 9 is shut down to avoid the compressor 9 not being shut down affecting the operation 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 inlet and outlet water temperature difference of the cooler coil 2 to adjust the heat exchange capacity of the cooler coil 2; that is, if the inlet and outlet water temperature difference of the cooler coil 2 is too small, the opening of the main control valve 4 is increased to increase the flow rate through the cooler coil 2; if the inlet and outlet water temperature difference of the cooler coil 2 is too large, the opening of the main control valve 4 is reduced to reduce the flow rate through the cooler coil 2 to maintain the cold source provided by the cooler coil 2 and the cooling capacity required by the computer room within a roughly consistent range.

[0076] When switching from the pre-cooling mode to the compressor cooling mode, it specifically includes:

[0077] The first and second ends of the three-way valve 3 are controlled to be gradually adjusted to be connected between the second and third ends, the main control valve 4 remains closed, the bypass valve 5 remains turned on, and the compressor 9 remains running to operate the compressor cooling mode. When the compressor cooling 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 inlet and outlet water temperature difference of the surface cooler coil 2.

[0078] When switching from natural cooling mode to pre-cooling mode, it specifically includes:

[0079] The main control valve 4 is controlled to be closed, and the bypass valve 5 is controlled to be turned on. During the closing process of the main control valve 4, the opening of the bypass valve 5 is adjusted based on the current opening of the main control valve 4 and the inlet and outlet water temperature difference of the surface cooler coil 2. Specifically, the opening of the bypass valve 5 is the current opening of the main control valve 4 + the set opening value, and the set opening value is determined based on the inlet and outlet water temperature difference of the surface cooler coil 2; the opening of the bypass valve 5 is adjusted based on the current opening of the main control valve 4 and the inlet and outlet water temperature difference of the surface cooler coil 2, so as to adjust the flow of chilled water flowing into the condenser 8 and maintain sufficient heat released by the refrigerant. After the bypass valve 5 is turned on, the compressor 9 is controlled to run with a delay (0s-120s), and the first end and the second end of the three-way valve 3 are turned on to run the pre-cooling mode. Among them, when running the pre-cooling mode, 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 inlet and outlet water temperature difference of the surface cooler coil 2.

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

[0081] It should be noted that, in this specification, relational terms such as first and second are merely used to distinguish one entity from other entities, but do not necessarily require or imply any actual relationship or order between these entities.

[0082] Specific examples are used herein to illustrate the principles and implementation methods of the present application, and the description of the above embodiments is only used to help understand the method and core ideas of the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A dual cold source air conditioning unit, characterized in that: include: A natural cooling system comprises a chilled water circulation circuit (1), a condenser coil (2) and a cooling unit arranged on the chilled water circulation circuit (1), wherein a three-way valve (3) and a main control valve (4) are arranged on the chilled water circulation circuit (1) at the liquid outlet end of the condenser coil (2), a first end of the three-way valve (3) is connected to the liquid outlet end of the condenser coil (2), a second end of the three-way valve (3) is connected to the main control valve (4), and a third end of the three-way valve (3) is connected to the chilled water circulation circuit (1) at the liquid inlet end of the condenser coil (2), a bypass channel (6) connected in parallel with the main control valve (4) is also arranged on the chilled water circulation circuit (1), and a bypass valve (5) is arranged on the bypass channel (6); A compressor refrigeration system, comprising a compressor (9), an evaporator (11), a condenser (8) and a throttling element (10), wherein 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) performs heat exchange with the refrigerant in the condenser (8) to remove heat from the refrigerant.

2. The dual cold source air conditioning unit according to claim 1, characterized in that: The condenser (8) is a condensation plate exchanger, wherein a first passage communicating with the bypass channel (6) is provided in the condensation plate exchanger, and a second passage communicating with the refrigerant circulation circuit (7) is also provided in the condensation plate exchanger, wherein the first passage and the second passage are independently arranged.

3. The dual cold source air conditioning unit according to claim 2, characterized in that: The evaporator (11) is an evaporating coil, and a third passage connected to the refrigerant circulation circuit (7) is provided in the evaporating coil. The evaporating coil corresponds to the position of the condenser coil (2) and is connected in series in the airflow direction, so that the return air from the machine room passes through the condenser coil (2) and the evaporating coil and then is delivered to the machine room.

4. The dual cold source air conditioning unit according to claim 3, characterized in that: There are two groups of compressor refrigeration systems, and the two groups of compressor refrigeration systems share one condensing plate heat exchanger and one evaporating coil. The number of the second passages in the condensing plate heat exchanger is two, and the two second passages are independently set. The number of the third passages in the evaporating plate heat exchanger is two, and the two third passages are crossed and independently set.

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

6. A control method, characterized in that: The dual cold source air conditioning unit according to any one of claims 1 to 5 comprises: Determine the current operation mode of the air conditioning unit, the operation mode including: compressor cooling mode, precooling mode, and natural cooling mode; When the compressor is running in cooling mode, if the water inlet temperature of the condenser coil (2) is less than or equal to the return air temperature of the machine room and lasts for a preset time, the first end and the second end of the three-way valve (3) are controlled to be connected, the main control valve (4) is controlled to be closed, the bypass valve (5) is controlled to be connected, and the compressor (9) is controlled to run; When the precooling mode is running, if the water inlet 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 end and the second end of the three-way valve (3) are controlled to be connected, the main control valve (4) is controlled to be connected, the bypass valve (5) is controlled to be closed, and the compressor (9) is controlled to be turned off; When the precooling mode is running, if the inlet water temperature is greater than the return air temperature and lasts for a preset time, the second end and the third end of the three-way valve (3) are controlled to be connected, the main control valve (4) is controlled to be closed, the bypass valve (5) is controlled to be connected, and the compressor (9) is controlled to run; When the natural cooling mode is operated, if the opening of the main control valve (4) is greater than or equal to a preset opening, and the actual supply air temperature is greater than the preset supply air temperature and lasts for a preset time, or if the inlet water temperature is greater than or equal to the preset supply air temperature and lasts for a preset time, the first end and the second end of the three-way valve (3) are controlled to be connected, the main control valve (4) is controlled to be closed, the bypass valve (5) is controlled to be connected, and the compressor (9) is controlled to operate.

7. The control method according to claim 6, characterized in that: The step of determining the current operating mode of the air conditioning unit comprises: When the air-conditioning unit is started, if the water inlet temperature is greater than or equal to the preset return air temperature, it is started 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 water inlet temperature and less than the preset return air temperature, it is started in the pre-cooling mode, and the current operating mode is the pre-cooling mode; if the water inlet temperature is less than or equal to the preset supply air temperature, it is started in the natural cooling mode, and the current operating mode is the natural cooling mode; During the operation of the air conditioning unit, determining a current operation mode of the air conditioning unit based on the current states 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 end and the third end of the three-way valve (3) are connected, the bypass valve (5) is connected, 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 end and the second end of the three-way valve (3) are connected, the bypass valve (5) is connected, 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 turned on, the first end and the second end of the three-way valve (3) are turned on, the bypass valve (5) is turned off, and the compressor (9) is turned off, then the operating mode is determined to be the natural cooling mode.

8. The control method according to claim 7, characterized in that: When the pre-cooling 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 inlet and outlet water temperature difference of the surface cooler coil (2); When the compressor refrigeration mode is operated, 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 inlet and outlet water temperature difference of the condenser coil (2).

9. The control method according to claim 7, characterized in that: The steps of controlling the first end and the second end of the three-way valve (3) to be conductive, controlling the main control valve (4) to be conductive, controlling the bypass valve (5) to be closed, and controlling the compressor (9) to be turned off include: The main control valve (4) is controlled to be turned on with a delay after the compressor (9) is turned off, and the bypass valve (5) is controlled to be turned off step by step after the compressor (9) is turned off and delayed for a preset time. 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.

10. The control method according to claim 7, characterized in that: The steps of controlling the first end and the second end of the three-way valve (3) to be connected, controlling the main control valve (4) to be closed, controlling the bypass valve (5) to be connected, and controlling the operation of the compressor (9) include: During the closing process of the main control valve (4), the opening of the bypass valve (5) is adjusted based on the current opening of the main control valve (4) and the temperature difference between the inlet and outlet water of the condenser coil (2), and the compressor (9) is controlled to run for a delayed time after the bypass valve (5) is turned on.

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