Double-cold-source air conditioning unit and control method

Abstract

The invention discloses a double-cold-source air conditioning unit and a control method, and the air conditioning unit comprises a natural cooling system which comprises a chilled water circulation loop and a surface air cooler coil pipe arranged on the chilled water circulation loop, and the surface air cooler coil pipe is connected with the chilled water circulation loop along the flowing path of chilled water in the chilled water circulation loop; a first bypass channel and a second bypass channel are sequentially arranged on the chilled water circulation loop, and the first bypass channel is connected with the surface air cooler coil in parallel; the compressor refrigerating system comprises a compressor, an evaporator and a condenser which are connected to form a refrigerant circulation loop; the temperature detection system comprises a plurality of temperature sensors and is used for detecting the air supply temperature of the air conditioning unit, the water inlet and outlet temperature of the surface air cooler coil and the air return temperature of the air conditioning unit; and the chilled water in the second 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 multiple working modes cannot be switched automatically. Usually manual switching is required, which has low switching efficiency and affects the reliability of the computer room. At the same time, manual switching does not follow the principle of smooth transition between multiple working modes, and it is easy for the temperature in the computer room to drop or rise suddenly, affecting the safe operation of the equipment in the computer room and reducing the life of the equipment.

[0005] Therefore, in view of the above technical problems, how to achieve smooth and automatic 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, which solves the problem of low switching efficiency caused by manual switching and the inability to smoothly and automatically switch between multiple working modes.

[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 and a surface cooler coil arranged on the chilled water circulation loop, wherein a first bypass channel and a second bypass channel are sequentially arranged on the chilled water circulation loop along a flow path of the chilled water in the chilled water circulation loop, and the first bypass channel is connected in parallel with the surface cooler coil;

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

[0010] A temperature detection system, comprising a plurality of temperature sensors, wherein 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 condenser coil, and the return air temperature of the air conditioning unit;

[0011] The chilled water in the second bypass channel performs heat exchange with the refrigerant in the condenser to take away the heat of the refrigerant.

[0012] 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.

[0013] 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.

[0014] 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.

[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 cooling mode is running, if the water inlet temperature of the surface cooler coil is less than or equal to the return air temperature of the machine room and lasts for a preset time, it will automatically switch to the pre-cooling mode;

[0018] When the pre-cooling 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 the preset time, it is automatically switched to the natural cooling mode; 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 the preset time, it is automatically switched to the natural cooling mode;

[0019] When the pre-cooling mode is running, if the water inlet temperature is greater than the return air temperature and lasts for a preset time, it automatically switches to the compressor cooling mode;

[0020] When running in the natural cooling mode, if the flow in the chilled water circulation loop is greater than or equal to the preset flow, and the actual supply air temperature is greater than the preset supply air temperature and lasts for a preset time, it automatically switches to running in the pre-cooling mode; or, if the inlet water temperature is greater than or equal to the preset supply air temperature and lasts for a preset time, it automatically switches to running in the pre-cooling mode.

[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, the current operation mode of the air conditioning unit is determined based on the current states of the condenser coil, the first bypass channel, the second bypass channel, the chilled water circulation loop and the compressor;

[0025] If the second bypass channel is connected, the chilled water circulation circuit corresponding to the second bypass channel in parallel is turned off, the first bypass channel is connected, the condenser coil is turned off, and the compressor is running, then the operating mode is determined to be the compressor cooling mode;

[0026] If the second bypass channel is connected, the chilled water circulation circuit corresponding to the second bypass channel in parallel is turned off, the first bypass channel is turned off, the surface cooler coil is turned on, and the compressor is running, then the operation mode is determined to be the precooling mode;

[0027] If the second bypass channel is closed, the chilled water circulation circuit corresponding to the second bypass channel in parallel is turned on, the first bypass channel is closed, the condenser coil is turned on, and the compressor is turned off, the operating mode is determined to be the natural cooling mode.

[0028] Preferably, the step of automatically switching from operating the compressor refrigeration mode to operating the precooling mode comprises:

[0029] The first bypass channel is controlled to be gradually closed, and the surface cooler coil is controlled to be gradually opened, the second bypass channel is controlled to remain closed, the chilled water circulation loop corresponding to the second bypass channel is controlled to remain closed in parallel, and the compressor is controlled to remain running to run the pre-cooling mode. When running the pre-cooling mode, the compressor adjusts the frequency according to the cooling demand of the machine room, and the flow in the second bypass channel is adjusted according to the inlet and outlet water temperature difference of the surface cooler coil.

[0030] Preferably, the step of automatically switching from running in the precooling mode to running in the natural cooling mode comprises:

[0031] Control the first bypass channel to remain closed, control the condenser coil to remain open, control the compressor to shut down, and control the chilled water circulation loop corresponding to the second bypass channel in parallel to delay conduction after the compressor is shut down, control the second bypass channel to be shut down and delay shutdown when the compressor is shut down to run the natural cooling mode, and when running the natural cooling mode, the flow in the chilled water circulation loop is adjusted according to the actual supply air temperature.

[0032] Preferably, the step of automatically switching from running in the precooling mode to running in the compressor refrigeration mode comprises:

[0033] The condenser coil is controlled to be gradually closed, and the first bypass channel is controlled to be gradually opened, the chilled water circulation loop corresponding to the second bypass channel is controlled to remain closed in parallel, the second bypass channel is controlled to remain opened, and the compressor is controlled to remain running to run the compressor cooling mode, and when running the compressor cooling mode, the compressor adjusts the frequency according to the cooling demand of the machine room, and the flow in the second bypass channel is adjusted according to the inlet and outlet water temperature difference of the condenser coil.

[0034] Preferably, the step of automatically switching from running in the natural cooling mode to running in the precooling mode comprises:

[0035] Control the chilled water circulation loop corresponding to the second bypass channel in parallel to be shut down, control the second bypass channel to remain connected, and during the shutdown of the chilled water circulation loop, the flow in the second bypass channel is adjusted based on the current flow of the chilled water circulation loop and the inlet and outlet water temperature difference of the condenser coil, and after the second bypass channel is turned on, control the compressor to delay operation, control the condenser coil to remain open, and control the first bypass channel to remain closed to run the pre-cooling mode, and when running the pre-cooling mode, the compressor adjusts the frequency according to the cooling demand of the machine room, and the flow in the second bypass channel is adjusted according to the inlet and outlet water temperature difference.

[0036] Compared with the prior art, the technical solution provided by this application has at least the following beneficial effects:

[0037] The air conditioning unit of the present application can adjust the operating mode by changing the state of the first bypass channel, the second bypass channel, the surface cooler coil, the chilled water circulation loop and the compressor. The operating 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. Based on the above, the present application realizes automatic switching between the compressor refrigeration mode and the pre-cooling mode, and between the pre-cooling mode and the natural cooling mode, thereby realizing automatic switching between various modes.

[0038] At the same time, when switching modes, the air-conditioning unit of the present application also follows the switching principles from compressor cooling 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 cooling mode, avoiding direct switching from natural cooling mode to compressor cooling mode, and preventing problems such as sudden temperature rise and drop in the machine room. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] 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.

[0040] FIG1 is a schematic diagram of a principle of a dual cold source air conditioning unit provided in an embodiment of the present application;

[0041] 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.

[0042] In the figure: 1-chilled water circulation loop; 2-surface cooler coil; 3-three-way valve; 4-first bypass channel; 5-main control valve; 6-bypass valve; 7-second bypass channel; 8-refrigerant circulation loop; 9-condenser; 10-compressor; 11-expansion valve; 12-evaporator; 13-temperature sensor. DETAILED DESCRIPTION

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] Along the flow path direction of the chilled water in the chilled water circulation loop 1, a first bypass channel 4 and a second bypass channel 7 are sequentially provided on the chilled water circulation loop 1, that is, when the chilled water flows along the chilled water circulation loop 1, it first reaches the position of the first bypass channel 4, and then reaches the position of the second bypass channel 7; the first bypass channel 4 is connected in parallel with the condenser coil 2, so that the chilled water can flow through the condenser coil 2 or the first bypass channel 4 according to the status of the first bypass channel 4 and the condenser coil 2.

[0048] Similarly, the chilled water can determine whether the chilled water flows through the second bypass channel 7 or the corresponding parallel freezing chamber circulation circuit according to the state of the second bypass channel 7 and the chilled water circulation circuit 1 connected in parallel with the second bypass channel 7.

[0049] In some embodiments, a three-way valve 3 and a main control valve 5 may be provided on the chilled water circulation loop 1 at the liquid outlet end of the condenser coil 2, 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 5, 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 through the first bypass channel 4. It is understandable that the three-way valve 3 has three ports, two of which remain open and the other port remains closed.

[0050] The main control valve 5 is arranged on the chilled water circulation loop 1 corresponding to the second bypass channel 7 in parallel, that is, the second bypass channel 7 is connected in parallel with the main control valve 5 , and the bypass valve 6 is arranged on the second bypass channel 7 .

[0051] Based on the above embodiment, the flow path of the chilled water can be changed by changing the state of the three-way valve 3. For example, when the first end and the second end of the three-way valve 3 are connected, the chiller is in an open state, and the chilled water can pass through the chiller 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 chiller coil 2, and the chiller coil 2 is in a closed state. The chilled water directly flows from the first bypass channel 4 to the three-way valve 3, and flows from the third end of the three-way valve 3 to the second end, and finally flows in the direction of the main control valve 5. Similarly, by changing the state of the main control valve 5 and the bypass valve 6, the flow path of the chilled water in the chilled water circulation loop 1 and the second bypass channel 7 can also be changed, which will not be repeated here.

[0052] 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 10 and enters the condenser 9, where it releases heat, and then enters the evaporator 12 through the throttling and pressure reduction of the expansion valve 11 to exchange heat with the return air in the machine room, and then enters the compressor 10 to form a cycle. Specifically, the compressor refrigeration system includes a compressor 10, an evaporator 12 and a condenser 9, which are connected to form a refrigerant circulation loop 8; the compressor refrigeration system also includes an expansion valve 11, an intake pressure detector, an intake temperature detector, a condensation pressure detector, and a condensation temperature detector, etc., and reference may be made to the prior art.

[0053] When the chilled water flows through the second bypass channel 7, the chilled water in the second bypass channel 7 can also exchange heat with the refrigerant in the condenser 9, thereby taking away the heat of the refrigerant; 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 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 9, it exchanges heat with the chilled water flowing through the condenser 9 and releases heat to reduce the condensation pressure of the condenser 9 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 9, thereby exchanging heat with the refrigerant in the condenser 9 to take away heat.

[0054] 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.

[0055] The temperature detection system includes a plurality of temperature sensors 13, 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.

[0056] Among them, the condenser 9 in the compressor refrigeration system can be a condensation plate exchanger, and a second passage connected to the second bypass channel 7 is provided in the condensation plate exchanger. A first passage connected to the refrigerant circulation loop 8 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 second passage through the bypass channel, and the refrigerant can enter the first passage through the refrigerant circulation loop 8, so that the chilled water and the refrigerant exchange heat at the condensation plate exchanger to cool the refrigerant.

[0057] The corresponding evaporator 12 can be an evaporating coil, and a third passage connected to the refrigerant circulation circuit 8 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.

[0058] 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.

[0059] 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 first passages in the condensing plate is two, corresponding to two refrigerant circulation loops 8, and the two first 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.

[0060] 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:

[0061] Determine the current operation mode of the air conditioning unit, the operation modes include: compressor cooling mode, precooling mode, and natural cooling mode;

[0062] 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, and the surface cooler coil 2 can provide a certain amount of cooling. Therefore, after the preset stable operation time (60s-600s), it can automatically switch to the pre-cooling mode, thereby using the natural cooling system to provide a certain amount of cooling, reduce the operating frequency of the compressor 10, and reduce power consumption;

[0063] 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 10 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, so it can automatically switch to the natural cooling mode, 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 lower than the preset supply air temperature, and the compressor 10 runs at the minimum frequency for a preset time (0s-900s), it means that the compressor refrigeration system provides less cooling capacity, and the cooling capacity provided by the surface cooler coil 2 can also meet the supply air temperature requirement of the machine room, so it can also automatically switch to the natural cooling mode, and the cooling capacity is provided by the natural cooling system alone;

[0064] In addition, when running in 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 it can automatically switch to the compressor cooling mode, and the compressor cooling system alone provides cooling capacity;

[0065] When the natural cooling mode is in operation, if the flow rate in the chilled water circulation loop 1 is greater than or equal to the preset flow rate, and the actual supply air temperature is greater than the preset supply air temperature, and lasts for the preset time (30s-300s), it means that the natural cooling system is in full-power operation mode at this time. The cooling capacity provided is still unable to meet the cooling demand of the computer room, so it can automatically switch to the pre-cooling mode, and the natural cooling system and the compressor refrigeration system provide cooling capacity at the same time; or, when the natural cooling mode is in operation, 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 the preset time (0s-600s), it means that the surface cooler coil 2 may still have the ability to provide cooling, but the cooling capacity provided can no longer meet the requirements of the preset supply air temperature, so it is necessary to automatically switch to the pre-cooling mode, and the natural cooling system and the compressor refrigeration system provide cooling capacity at the same time.

[0066] The air conditioning unit of the present application can adjust the operation mode by changing the state of the first bypass channel 4, the second bypass channel 7, the surface cooler coil 2, the chilled water circulation loop 1 and the compressor 10. The operation modes include compressor cooling mode, precooling mode and natural cooling mode. The compressor cooling mode uses the compressor cooling system alone to provide cooling capacity, and the chilled water exchanges heat with the refrigerant; the precooling mode uses the compressor cooling system and the natural cooling system to provide cooling capacity at the same time, 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. Based on the above, the present application realizes the automatic switching between the compressor cooling mode and the precooling mode, and the automatic switching between the precooling mode and the natural cooling mode, thereby realizing the automatic switching between various modes. At the same time, when the air conditioning unit of the present application switches the mode, it also follows the switching principle from the compressor cooling mode to the precooling mode, the precooling mode to the natural cooling mode, the natural cooling mode to the precooling mode, and the precooling mode to the compressor cooling mode, so as to avoid the direct switching from the natural cooling mode to the compressor cooling mode, and prevent the problem of sudden temperature rise and drop in the machine room.

[0067] 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:

[0068] 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, so the compressor refrigeration system provides cooling capacity alone, and the corresponding unit should be started in the compressor refrigeration mode. At this time, the current operating mode is the compressor refrigeration mode;

[0069] If the preset supply air temperature is lower than the inlet water temperature of the condenser coil 2 and lower 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. However, since the inlet water temperature of the condenser coil 2 is higher 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. Therefore, the natural cooling system and the compressor refrigeration system need to provide cooling capacity at the same time and start in pre-cooling mode. At this time, the current operation mode is pre-cooling mode.

[0070] 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 demand of the computer room. At this time, the natural cooling system can provide cooling capacity alone and start in natural cooling mode. At this time, the current operating mode is natural cooling mode.

[0071] The steps of determining the operation mode of the air conditioning unit during operation include:

[0072] During the operation of the air conditioning unit, since the return air temperature, the supply air temperature, the water inlet temperature of the condenser 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 first bypass channel 4, the second bypass channel 7, the condenser coil 2, the chilled water circulation circuit 1 and the compressor 10;

[0073] If the second bypass channel 7 is connected, the chilled water circulation circuit 1 corresponding to the second bypass channel 7 is closed, the first bypass channel 4 is connected, the surface cooler coil 2 is closed, and the compressor 10 is running, that is, the corresponding bypass valve 6 is connected, the main control valve 5 is closed, the second end and the third end of the three-way valve 3 are connected (the surface cooler coil 2 is closed), and the compressor 10 is running, then the operation mode is determined to be the compressor cooling mode;

[0074] If the second bypass channel 7 is connected, the chilled water circulation circuit 1 corresponding to the second bypass channel 7 is closed, the first bypass channel 4 is closed, the surface cooler coil 2 is opened, and the compressor 10 is running, that is, the corresponding bypass valve 6 is connected, the main control valve 5 is closed, the first end and the second end of the three-way valve 3 are connected (the surface cooler coil 2 is opened), and the compressor 10 is running, then it is determined that the operation mode is the pre-cooling mode;

[0075] If the second bypass channel 7 is closed, the chilled water circulation circuit 1 connected in parallel with the second bypass channel 7 is connected, the first bypass channel 4 is closed, the surface cooler coil 2 is turned on, and the compressor 10 is turned off, that is, the corresponding bypass valve 6 is closed, the main control valve 5 is turned on, the first end and the second end of the three-way valve 3 are connected (the surface cooler coil 2 is turned on), and the compressor 10 is turned off, then it is determined that the operation mode is the natural cooling mode;

[0076] Correspondingly, when the air-conditioning unit operates in the above-mentioned different modes, the states of the above-mentioned first bypass channel 4, the second bypass channel 7, the condenser coil 2, the chilled water circulation circuit 1 and the compressor 10 should also remain corresponding.

[0077] 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.

[0078] The above points out the automatic switching logic between the modes. Therefore, on the basis of the air-conditioning unit selecting the automatic switching mode, the automatic and smooth switching between the modes can be realized. At the same time, the present application can also add semi-automatic switching and manual switching modes according to the actual situation. For example, when the air-conditioning unit selects the semi-automatic switching mode, the air-conditioning unit still follows the above-mentioned automatic switching logic, but adds a scheme that requires the user to manually confirm whether to switch the mode. Click "Confirm" and the air-conditioning unit will switch according to the automatic switching mode. If there is no operation, after the preset time (2 minutes) or the user motor "cancels", the current operating mode will be maintained and continued to operate. After the preset time (5 minutes to 60 minutes), the user is required to manually confirm whether to switch the mode again. For another example, when the air-conditioning unit selects the manual switching mode, the unit only switches according to the manually set operating mode. The optional modes of manually setting the mode include compressor refrigeration mode, precooling mode, and natural cooling mode. After the manual setting of the operating mode, the air-conditioning unit adjusts from the current operating mode to the manually set operating mode.

[0079] It should be pointed out that for the above-mentioned automatic switching mode, semi-automatic switching mode and manual switching mode, the switching principles of the three operating modes should be followed: switching principles from compressor cooling 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 cooling mode, so as to prevent the problem of sudden rise and drop in temperature in the computer room.

[0080] The step of automatically switching from operating the compressor refrigeration mode to operating the precooling mode includes:

[0081] The first bypass channel 4 is controlled to be gradually closed, and the corresponding surface cooler coil 2 will also be gradually opened. The second bypass channel 7 is controlled to remain closed, and the chilled water circulation loop 1 corresponding to the second bypass channel 7 is controlled to remain closed in parallel, and the compressor 10 is controlled to keep running to run the pre-cooling mode. When running in the pre-cooling mode, the compressor 10 adjusts the frequency according to the cooling demand of the machine room, and the opening of the bypass valve 6 or the flow in the second bypass channel 7 is PID-regulated according to the inlet and outlet water temperature difference of the surface cooler coil 2.

[0082] The steps of automatically switching from the pre-cooling mode to the natural cooling mode include:

[0083] Control the first bypass channel 4 to remain closed, control the surface cooler coil 2 to remain open, control the compressor 10 to close, and control the chilled water circulation loop 1 corresponding to the second bypass channel 7 to delay (0s-300s) to open in parallel after the compressor 10 is closed, and control the second bypass channel 7 to step-close after the compressor 10 is closed and delayed (0s-300s) to run the natural cooling mode. When the natural cooling mode is running, the flow in the chilled water circulation loop 1 or the opening of the main control valve 5 is adjusted according to the actual supply air temperature. After the compressor 10 is closed and delayed for a preset time, the main control valve 5 is controlled to be turned on and the bypass valve 6 is controlled to be closed, that is, the natural cooling mode is switched after the compressor 10 is closed to avoid the compressor 10 not being closed affecting the operation of the natural cooling mode;

[0084] At the same time, during the switching process from the pre-cooling mode to the natural cooling mode, the flow in the chilled water circulation loop 1 or the opening of the main control valve 5 should be adjusted based on the inlet and outlet water temperature difference of the condenser coil 2 to adjust the heat exchange capacity of the condenser coil 2; that is, if the inlet and outlet water temperature difference of the condenser coil 2 is too small, the opening of the main control valve 5 is increased to increase the flow through the condenser coil 2; if the inlet and outlet water temperature difference of the condenser coil 2 is too large, the opening of the main control valve 5 is reduced to reduce the flow through the condenser coil 2 to maintain the cold source provided by the condenser coil 2 and the cooling capacity required by the computer room within a roughly consistent range.

[0085] The steps of automatically switching from the pre-cooling mode to the compressor cooling mode include:

[0086] The surface cooler coil 2 is controlled to be gradually closed, and the first bypass channel 4 is controlled to be gradually turned on, the chilled water circulation loop 1 corresponding to the second bypass channel 7 in parallel is controlled to remain closed, the second bypass channel 7 is controlled to remain turned on, and the compressor 10 is controlled to remain running to operate the compressor refrigeration mode. When the compressor refrigeration mode is operated, the compressor 10 adjusts the frequency according to the cooling demand of the machine room, and the flow in the second bypass channel 7 or the opening of the bypass valve 6 is adjusted according to the inlet and outlet water temperature difference of the surface cooler coil 2.

[0087] The steps of automatically switching from the natural cooling mode to the pre-cooling mode include:

[0088] The chilled water circulation loop 1 corresponding to the second bypass channel 7 connected in parallel is controlled to be shut down, and the second bypass channel 7 is controlled to remain open. During the process of shutting down the chilled water circulation loop 1, the flow in the second bypass channel 7 is adjusted based on the current flow of the chilled water circulation loop 1 and the inlet and outlet water temperature difference of the surface cooler coil 2. Specifically, the opening of the bypass valve 6 is the opening of the current main control valve 5 + 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 chilled water flow flowing into the condenser 9 can be adjusted to maintain sufficient heat release by the refrigerant; after the second bypass channel 7 is turned on, the compressor 10 is controlled to delay (0s-120s) operation, the surface cooler coil 2 is controlled to remain open, and the first bypass channel 4 is controlled to remain closed to run the pre-cooling mode; wherein, when running the pre-cooling mode, the compressor 10 adjusts the frequency according to the cooling demand of the machine room, and the flow in the second bypass channel 7 or the opening of the bypass valve 6 is adjusted according to the inlet and outlet water temperature difference of the surface cooler coil 2.

[0089] 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.

[0090] 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.

[0091] 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 loop (1) and a surface cooler coil (2) arranged on the chilled water circulation loop (1), wherein a first bypass channel (4) and a second bypass channel (7) are sequentially arranged on the chilled water circulation loop (1) along a flow path of chilled water in the chilled water circulation loop (1), and the first bypass channel (4) is connected in parallel with the surface cooler coil (2); A compressor refrigeration system, comprising a compressor (10), an evaporator (12), a condenser (9) and a throttling element, wherein the compressor (10), the evaporator (12), the condenser (9) and the throttling element are connected to form a refrigerant circulation loop (8); A temperature detection system, comprising a plurality of temperature sensors (13), the temperature detection system being used to detect the supply air temperature of the air conditioning unit, the inlet and outlet water temperatures of the condenser coil (2), and the return air temperature of the air conditioning unit; The chilled water in the second bypass channel (7) performs heat exchange with the refrigerant in the condenser (9) to remove heat from the refrigerant.

2. The dual cold source air conditioning unit according to claim 1, characterized in that: The condenser (9) is a condensation plate exchanger, wherein a second passage communicating with the bypass channel is provided in the condensation plate exchanger, and a first passage communicating with the refrigerant circulation circuit (8) 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 (12) is an evaporating coil, and a third passage connected to the refrigerant circulation circuit (8) 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 first passages in the condensing plate heat exchanger is two, and the two first 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. A control method, characterized in that: The dual cold source air conditioning unit according to any one of claims 1 to 4 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 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 and lasts for a preset time, it automatically switches to the pre-cooling mode; When the pre-cooling mode is in operation, if the water inlet temperature is less than or equal to the preset air supply temperature of the machine room, and the compressor (10) operates at the minimum frequency for a preset time, the operation is automatically switched to the natural cooling mode; or, if the actual air supply temperature of the machine room is less than the preset air supply temperature, and the compressor (10) operates at the minimum frequency for a preset time, the operation is automatically switched to the natural cooling mode; When the pre-cooling mode is running, if the water inlet temperature is greater than the return air temperature and lasts for a preset time, it automatically switches to the compressor cooling mode; When the natural cooling mode is running, if the flow rate in the chilled water circulation circuit (1) is greater than or equal to a preset flow rate, and the actual supply air temperature is greater than the preset supply air temperature and lasts for a preset time, it automatically switches to running the pre-cooling mode; or, if the inlet water temperature is greater than or equal to the preset supply air temperature and lasts for a preset time, it automatically switches to running the pre-cooling mode.

6. The control method according to claim 5, 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, the current operation mode of the air conditioning unit is determined based on the current states of the condenser coil (2), the first bypass channel (4), the second bypass channel (7), the chilled water circulation circuit (1) and the compressor (10); If the second bypass channel (7) is connected, the chilled water circulation circuit (1) corresponding to the second bypass channel (7) is disconnected, the first bypass channel (4) is connected, the condenser coil (2) is turned off, and the compressor (10) is running, then the operating mode is determined to be the compressor cooling mode; If the second bypass channel (7) is turned on, the chilled water circulation circuit (1) connected in parallel with the second bypass channel (7) is turned off, the first bypass channel (4) is turned off, the surface cooler coil (2) is turned on, and the compressor (10) is running, then the operating mode is determined to be the pre-cooling mode; If the second bypass channel (7) is closed, the chilled water circulation circuit (1) corresponding to the second bypass channel (7) in parallel is turned on, the first bypass channel (4) is closed, the condenser coil (2) is turned on, and the compressor (10) is turned off, then the operating mode is determined to be the natural cooling mode.

7. The control method according to claim 6, characterized in that: The step of automatically switching from operating the compressor in refrigeration mode to operating the precooling mode comprises: The first bypass channel (4) is controlled to be gradually closed, and the surface cooler coil (2) is controlled to be gradually opened, the second bypass channel (7) is controlled to remain closed, the chilled water circulation loop (1) connected in parallel with the second bypass channel (7) is controlled to remain closed, and the compressor (10) is controlled to remain running to run the pre-cooling mode. When running the pre-cooling mode, the compressor (10) adjusts the frequency according to the cooling demand of the machine room, and the flow in the second bypass channel (7) is adjusted according to the inlet and outlet water temperature difference of the surface cooler coil (2).

8. The control method according to claim 6, characterized in that: The step of automatically switching from running in the precooling mode to running in the natural cooling mode comprises: The first bypass channel (4) is controlled to remain closed, the surface cooler coil (2) is controlled to remain open, the compressor (10) is controlled to be closed, and after the compressor (10) is closed, the chilled water circulation circuit (1) corresponding to the second bypass channel (7) is controlled to be delayed to be turned on, and the second bypass channel (7) is controlled to be closed and delayed to be turned off in the compressor (10) to operate the natural cooling mode, and when the natural cooling mode is operated, the flow rate in the chilled water circulation circuit (1) is adjusted according to the actual supply air temperature.

9. The control method according to claim 6, characterized in that: The step of automatically switching from running in the precooling mode to running in the compressor refrigeration mode comprises: The surface cooler coil (2) is controlled to be gradually closed, and the first bypass channel (4) is controlled to be gradually opened, the chilled water circulation loop (1) connected in parallel with the second bypass channel (7) is controlled to remain closed, the second bypass channel (7) is controlled to remain opened, and the compressor (10) is controlled to remain running, so as to operate the compressor cooling mode. When the compressor cooling mode is operated, the compressor (10) adjusts the frequency according to the cooling demand of the machine room, and the flow rate in the second bypass channel (7) is adjusted according to the inlet and outlet water temperature difference of the surface cooler coil (2).

10. The control method according to claim 6, characterized in that: The step of automatically switching from running in the natural cooling mode to running in the precooling mode comprises: The chilled water circulation circuit (1) connected in parallel with the second bypass channel (7) is controlled to be shut down, and the second bypass channel (7) is controlled to remain connected. During the process of shutting down the chilled water circulation circuit (1), the flow rate in the second bypass channel (7) is adjusted based on the current flow rate of the chilled water circulation circuit (1) and the inlet and outlet water temperature difference of the condenser coil (2). After the second bypass channel (7) is turned on, the compressor (10) is controlled to delay operation, the condenser coil (2) is controlled to remain open, and the first bypass channel (4) is controlled to remain closed to operate the pre-cooling mode. When the pre-cooling mode is operated, the compressor (10) adjusts the frequency according to the cooling demand of the machine room, and the flow rate in the second bypass channel (7) is adjusted according to the inlet and outlet water temperature difference.

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