A control method of a machine room air conditioning system

Abstract

The embodiment of the application discloses a control method of a computer room air conditioning system, and is used in the field of air conditioning refrigeration technology. In the computer room air conditioning system, the water inlet end of the computer room air conditioning system is connected with the input end of the cooling coil and the first end of the first valve, the second end of the first valve is connected with the output end of the cooling coil, the third end of the first valve is connected with the water inlet of the plate heat exchanger and one end of the second valve; the water outlet of the plate heat exchanger is connected with one end of the third valve, the other end of the third valve is connected with the other end of the second valve and the water outlet end of the computer room air conditioning system; the output end of the evaporating coil is connected with the input end of the compressor, the output end of the compressor is connected with the input port of the plate heat exchanger; the output port of the plate heat exchanger is connected with one end of the electronic expansion valve, the other end of the electronic expansion valve is connected with the input end of the evaporating coil; the power consumption of the compressor in the compressor refrigeration unit can be effectively reduced, and the energy saving of the computer room air conditioner is beneficial.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the air conditioning refrigeration technical field, and particularly relates to a control method of a machine room air conditioning system. BACKGROUND

[0002] At present, a load (such as a transformer and a power transformation cabinet in a power distribution machine room, a switch and a router in a communication machine room, etc.) is arranged in a machine room, and a large amount of heat is generated when the load runs. At this time, the running temperature of the load is too high, which is not conducive to the normal operation of the load. An air conditioner is usually installed in the machine room to refrigerate the load.

[0003] However, in the existing machine room air conditioner, the load is refrigerated by a compressor. In order to maintain the running temperature of the load in a low-temperature state, the machine room air conditioner needs to be refrigerated continuously. At this time, the power consumption of the compressor will be greatly increased, which is not conducive to the energy saving of the machine room air conditioner. SUMMARY

[0004] The embodiment of the present application provides a control method of a machine room air conditioning system, which can effectively reduce the power consumption of the compressor and is conducive to the energy saving of the machine room air conditioner.

[0005] The embodiment of the present application provides a machine room air conditioning system, which comprises a compressor refrigeration unit and a natural cooling unit.

[0006] The natural cooling unit comprises a surface cooler coil, a first valve and a second valve, and the compressor refrigeration unit comprises a compressor, an evaporation coil, a plate heat exchanger, an electronic expansion valve and a third valve.

[0007] The water inlet end of the machine room air conditioning system is connected with the input end of the surface cooler coil and the first end of the first valve. The second end of the first valve is connected with the output end of the surface cooler coil. The third end of the first valve is connected with the water inlet of the plate heat exchanger and one end of the second valve.

[0008] The water outlet of the plate heat exchanger is connected with one end of the third valve. The other end of the third valve is connected with the other end of the second valve and the water outlet end of the machine room air conditioning system.

[0009] The output end of the evaporation coil is connected with the input end of the compressor. The output end of the compressor is connected with the input port of the plate heat exchanger.

[0010] The output port of the plate heat exchanger is connected with one end of the electronic expansion valve. The other end of the electronic expansion valve is connected with the input end of the evaporation coil.

[0011] Further, the natural cooling unit further comprises a water inlet temperature detector, a water outlet temperature detector and a flow meter.

[0012] The water inlet temperature detector and the flow meter are arranged at a water inlet end of the machine room air conditioning system.

[0013] The water outlet temperature detector is arranged at a water outlet end of the machine room air conditioning system.

[0014] Further, the compressor refrigeration unit further comprises a suction pressure detector, a suction temperature detector, a condensation pressure detector, and a condensation temperature detector.

[0015] The suction pressure detector and the suction temperature detector are arranged between an output end of the evaporating coil and an input end of the compressor.

[0016] The condensation pressure detector and the condensation temperature detector are arranged between an output port of the plate heat exchanger and the electronic expansion valve.

[0017] Embodiments of the present application also provide a control method of a machine room air conditioning system, the machine room air conditioning system comprising: a natural cooling unit and a compressor refrigeration unit, the natural cooling unit comprising: a cooling coil, a first valve, and a second valve, the compressor refrigeration unit comprising: a compressor, an evaporating coil, a plate heat exchanger, an electronic expansion valve, and a third valve.

[0018] The control method comprises:

[0019] In a current refrigeration mode of the machine room air conditioning system, heat exchange amounts of the cooling coil and the evaporating coil are obtained; wherein the refrigeration mode of the machine room air conditioning system comprises any one of a compressor refrigeration mode, a natural cooling mode, and a mixed precooling mode.

[0020] The heat exchange amounts of the cooling coil and the evaporating coil are compared with a heat exchange amount required by a load in the machine room air conditioning system, to determine a target refrigeration mode satisfying the heat exchange amount required by the load.

[0021] The current refrigeration mode of the machine room air conditioning system is switched to the target refrigeration mode.

[0022] Further, the comparison of the heat exchange amounts of the cooling coil and the evaporating coil with the heat exchange amount required by the load in the machine room air conditioning system to determine the target refrigeration mode satisfying the heat exchange amount required by the load comprises:

[0023] If the sum of the heat exchange amounts of the cooling coil and the evaporating coil matches the heat exchange amount required by the load, and the matching lasts for a first preset time length, the target refrigeration mode is determined as the mixed precooling mode.

[0024] If the heat exchange amount of the surface cooler coil matches the heat exchange amount required by the load and lasts for a second preset time length, it is determined that the target refrigeration mode is a natural cooling mode.

[0025] If the heat exchange amount of the evaporating coil matches the heat exchange amount required by the load and lasts for a third preset time length, it is determined that the target refrigeration mode is a compressor refrigeration mode.

[0026] Further, the method further comprises:

[0027] When the refrigeration mode operated by the machine room air conditioning system is a compressor refrigeration mode, the compressor is controlled to adjust the operation frequency based on the refrigeration demand of the load to adjust the supply air temperature of the evaporating coil to the load; the second end of the first valve and the second valve are controlled to be closed, and the third valve is controlled to adjust the valve opening degree based on the water inlet temperature difference; wherein the water inlet temperature difference is the difference between the water inlet temperature of the water inlet end of the machine room air conditioning system and the water outlet temperature of the water outlet end of the machine room air conditioning system;

[0028] When the refrigeration mode operated by the machine room air conditioning system is a natural cooling mode, the compressor is controlled to be closed, the second end of the first valve is controlled to be opened, the second valve is controlled to adjust the valve opening degree based on the supply air temperature of the surface cooler coil to the load, and the third valve is controlled to be closed;

[0029] When the refrigeration mode operated by the machine room air conditioning system is a mixed pre-cooling mode, the compressor is controlled to adjust the operation frequency based on the refrigeration demand of the load, the second end of the first valve is controlled to be opened, the second valve is controlled to be closed, and the third valve is controlled to adjust the valve opening degree based on the water inlet temperature difference.

[0030] Further, the current operating refrigeration mode is a compressor refrigeration mode, and the target refrigeration mode is a mixed pre-cooling mode;

[0031] The control of the machine room air conditioning system to switch the current operating refrigeration mode to the target refrigeration mode comprises:

[0032] The second end of the first valve is controlled to be opened to switch the machine room air conditioning system from the compressor refrigeration mode to the mixed pre-cooling mode.

[0033] Further, the current operating refrigeration mode is a natural cooling mode, and the target refrigeration mode is a mixed pre-cooling mode;

[0034] The control of the machine room air conditioning system to switch the current operating refrigeration mode to the target refrigeration mode comprises:

[0035] controlling the valve opening of the second valve to gradually close to full closing, controlling the third valve to adjust the valve opening based on the valve opening of the second valve and the water temperature difference, and starting the compressor after the third valve is opened to switch the machine room air conditioning system from the natural cooling mode to the hybrid precooling mode.

[0036] Further, the current running refrigeration mode is the hybrid precooling mode, and the target refrigeration mode is the natural cooling mode.

[0037] The control of the machine room air conditioning system to switch the current running refrigeration mode to the target refrigeration mode comprises:

[0038] controlling the compressor to close, controlling the second valve to open after the compressor is closed and delayed for a preset time length, and controlling the third valve to stepwise close after the compressor is closed and delayed for a preset time length based on the water temperature difference to switch the machine room air conditioning system from the hybrid precooling mode to the natural cooling mode.

[0039] Further, the current running refrigeration mode is the hybrid precooling mode, and the target refrigeration mode is the compressor refrigeration mode.

[0040] The control of the machine room air conditioning system to switch the current running refrigeration mode to the target refrigeration mode comprises:

[0041] controlling the second end of the first valve to close to switch the machine room air conditioning system from the hybrid precooling mode to the compressor refrigeration mode.

[0042] From the above technical solutions, the embodiments of the present application have the following advantages:

[0043] In the embodiments of the present application, the machine room air conditioning system comprises a compressor refrigeration unit and a natural cooling unit, two cold sources; the surface cooler coil of the natural cooling unit and the evaporating coil of the compressor refrigeration unit are used to refrigerate the load of the machine room air conditioning system, and when refrigerating the load of the machine room air conditioning system, not only the compressor refrigeration unit can be used for refrigeration, but also the natural cooling unit can be used for refrigeration, which can effectively reduce the power consumption of the compressor in the compressor refrigeration unit and is conducive to the energy saving of the machine room air conditioning. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0045] Figure 1 a schematic diagram of a machine room air conditioning system disclosed by an embodiment of the present application;

[0046] Figure 2 a schematic diagram of another machine room air conditioning system disclosed by an embodiment of the present application;

[0047] Figure 3 a control flow chart of a machine room air conditioning system disclosed by an embodiment of the present application;

[0048] Figure 4 a control flow chart of another machine room air conditioning system disclosed by an embodiment of the present application. DETAILED DESCRIPTION

[0049] In order to enable persons skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by persons skilled in the art without creative work fall within the scope of protection of the present application.

[0050] In the description of the embodiments of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0051] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0052] In the existing machine room air conditioner, the compressor is used to cool the load. In order to maintain the operating temperature of the load in a low temperature state, the machine room air conditioner needs to run continuously. At this time, the power consumption of the compressor will be greatly increased, which is not conducive to the energy saving of the machine room air conditioner. Therefore, the present application provides a machine room air conditioning system, which can effectively reduce the power consumption of the compressor in the compressor refrigeration unit, and is conducive to the energy saving of the machine room air conditioner, as shown in Figure 1 The specific implementation is as follows:

[0053] In the embodiment of the present application, the machine room air conditioning system comprises a compressor refrigeration unit and a natural cooling unit; the compressor refrigeration unit and the natural cooling unit are arranged indoors; wherein the natural cooling unit comprises a cooling coil 101, a first valve 102 and a second valve 103, and the compressor refrigeration unit comprises a compressor 201, an evaporating coil 202, a plate heat exchanger 203, an electronic expansion valve 204 and a third valve 205. The cooling coil 101 and the evaporating coil 202 are arranged at positions corresponding to loads of the machine room air conditioning system. It can be understood that the cooling coil 101 and the evaporating coil 202 can receive high-temperature return air output by the loads, and output low-temperature supply air to the loads after heat exchange, so as to refrigerate the loads.

[0054] The water inlet end of the machine room air conditioning system is connected with the input end of the cooling coil 101 and the first end of the first valve 102, the second end of the first valve 102 is connected with the output end of the cooling coil 101, and the third end of the first valve 102 is connected with the water inlet of the plate heat exchanger 203 and one end of the second valve 103. It can be understood that the first valve 102 has at least three ports, which can be a three-way valve or a four-way valve, and the specific type is not limited here; it can be understood that the first end and the third end of the first valve 102 remain open regardless of whether the machine room air conditioning system is in a refrigeration mode or a switching refrigeration mode, and the control process of the first valve 102 is mainly to control the opening and closing of the first valve 102. The water inlet end of the machine room air conditioning system is used to flow cooling water into the machine room air conditioning system.

[0055] The water outlet of the plate heat exchanger 203 is connected with one end of the third valve 205, the other end of the third valve 205 is connected with the other end of the second valve 103 and the water outlet end of the machine room air conditioning system; the output end of the evaporating coil 202 is connected with the input end of the compressor 201, the output end of the compressor 202 is connected with the input port of the plate heat exchanger 203; the output port of the plate heat exchanger 203 is connected with one end of the electronic expansion valve 204, and the other end of the electronic expansion valve 204 is connected with the input end of the evaporating coil 202.

[0056] When the computer room air conditioning system operates in the compressor refrigeration mode, the load is refrigerated by the compressor refrigeration unit, that is, the compressor 201 starts to operate, the first end and the third end of the first valve 102 are opened, the second end of the first valve 102 is closed (that is, the output end of the cooling coil 101 is closed), the second valve 103 is closed, and the third valve 205 is opened. At this time, the high-temperature and high-pressure refrigerant gas from the compressor 20 is input to the input port of the plate heat exchanger 203, the cooling water flowing into the water inlet end of the computer room air conditioning system flows to the water inlet port of the plate heat exchanger 203 through the first valve 102, and the cooling water in the plate heat exchanger 203 absorbs heat to condense the high-temperature and high-pressure refrigerant gas (that is, after the plate heat exchanger 203 exchanges heat with the high-temperature and high-pressure refrigerant gas), the water outlet of the plate heat exchanger 203 outputs the cooled water to the water outlet end of the computer room air conditioning system, and the output port of the plate heat exchanger 203 outputs low-temperature and low-pressure refrigerant, which can be liquid or gas-liquid mixture, and the specific place is not limited here; the refrigerant is throttled into two-phase refrigerant by the electronic expansion valve 204, enters the evaporating coil 202 to absorb heat and evaporate, becomes low-temperature and low-pressure refrigerant gas, and then enters the compressor 201 to be compressed, forming a cycle.

[0057] It can be understood that when the plate heat exchanger 203 does not exchange heat with the high-temperature and high-pressure refrigerant gas, the refrigerant input to the input port of the plate heat exchanger 203 and the refrigerant output from the output port of the plate heat exchanger 203 are both refrigerant gas. When the load is low (that is, the heat generated is small), the refrigerant entering the evaporating coil 202 cannot completely absorb heat and evaporate into refrigerant gas, at this time, the refrigerant in the compressor refrigeration unit is in a gas-liquid mixed state, that is, the refrigerant input to the input port of the plate heat exchanger 203 and the refrigerant output from the output port of the plate heat exchanger 203 are both gas-liquid mixture. That is, the refrigerant input to the input port of the plate heat exchanger 203 and the refrigerant output from the output port of the plate heat exchanger 203 can be gas, liquid or gas-liquid mixture, and the specific place is not limited here.

[0058] When the computer room air conditioning system operates in the natural cooling mode, the load is refrigerated by the natural cooling unit, that is, the compressor 201 is closed, the second end of the first valve is opened (that is, the output end of the cooling coil 101 is opened), the second valve 103 is opened, and the third valve 205 is closed. At this time, the cooling water flowing into the water inlet end of the computer room air conditioning system flows through the cooling coil 101, the cooling water absorbs heat from the high-temperature return air of the load, the output end of the cooling coil 101 outputs the cooled water, which flows to the water outlet end of the computer room air conditioning system through the first valve 102 and the second valve 103.

[0059] Preferably, the evaporating coil is a screw coil, which can increase the heat exchange area and improve the heat exchange effect of the evaporating coil; the fin cooler coil is a light coil (smooth water pipe), which can effectively avoid the dirt blockage of the cooling water and affect the heat exchange effect of the fin cooler coil.

[0060] In the embodiment of the application, the computer room air conditioning system comprises a compressor refrigeration unit and a natural cooling unit, two cold sources; the fin cooler coil of the natural cooling unit and the evaporating coil of the compressor refrigeration unit are arranged at positions corresponding to loads of the computer room air conditioning system, and when the loads of the computer room air conditioning system are refrigerated, not only the compressor refrigeration unit can be used for refrigeration, but also the natural cooling unit can be used for refrigeration, which can effectively reduce the power consumption of the compressor in the compressor refrigeration unit and is beneficial to the energy saving of the computer room air conditioning.

[0061] Further, in the embodiment of the application, the high-temperature return air of the load is exchanged for low-temperature supply air by the fin cooler coil and the evaporating coil to refrigerate the load; at this time, the heat exchange amount of the fin cooler coil and the heat exchange amount of the evaporating coil directly affect the refrigeration effect of the load, the higher the heat exchange amount, the better the refrigeration effect, and the lower the heat exchange amount, the worse the refrigeration effect; the refrigeration effect of the load can be determined by measuring the heat exchange amount of the fin cooler coil and the heat exchange amount of the evaporating coil.

[0062] As shown in Figure 2 The natural cooling unit further comprises a water inlet temperature detector 104, a water outlet temperature detector 105 and a flow meter 106; the water inlet temperature detector 104 and the flow meter 106 are arranged at the water inlet end of the computer room air conditioning system; and the water outlet temperature detector 105 is arranged at the water outlet end of the computer room air conditioning system. It can be understood that when the computer room air conditioning system operates in the natural cooling mode, the second valve 103 is opened and the third valve 205 is closed, at this time, the water inlet temperature detector 104 detects the water inlet temperature of the input end of the fin cooler coil 101, the water outlet temperature detector 105 detects the water outlet temperature of the output end of the fin cooler coil 101, and the flow meter 106 detects the flow of the cooling water flowing through the fin cooler coil 101; at this time, the heat exchange amount of the fin cooler coil = the temperature difference between the inlet and outlet water temperatures * flow * specific heat capacity can be obtained.

[0063] And the compressor refrigeration unit further comprises: suction pressure detector 206, suction temperature detector 207, condensing pressure detector 208 and condensing temperature detector 209; Suction pressure detector 206 and suction temperature detector 207 are arranged between the output end of the evaporative coil 202 and the input end of the compressor 201; The suction pressure detector 206 is used to detect the first pressure of the refrigerant gas output by the output end of the evaporative coil 202 (i.e. the pressure before the compressor 201 is compressed), and the suction temperature detector 207 is used to detect the first temperature of the refrigerant gas output by the output end of the evaporative coil 202 (i.e. the temperature before the compressor 201 is compressed). Condensing pressure detector 208 and condensing temperature detector 209 are arranged between the output port of plate heat exchanger 203 and electronic expansion valve 204; The condensing pressure detector 208 is used to detect the second pressure of the refrigerant gas output by the input end of the evaporative coil 202 (i.e. the pressure after the compressor 201 is compressed), and the condensing temperature detector 209 is used to detect the second temperature of the refrigerant gas output by the input end of the evaporative coil 202 (i.e. the temperature after the compressor 201 is compressed). At this time, the heat exchange capacity of the evaporative coil can be obtained = the pressure difference between the first pressure and the second pressure * the temperature difference between the first temperature and the second temperature * the frequency of the compressor.

[0064] It can be understood that the compressor refrigeration unit can be two groups, each compressor refrigeration unit is similar, with corresponding compressor and evaporative coil; Through the heat exchange of two evaporative coils, the heat exchange effect can be improved.

[0065] Further, when the existing machine room air conditioning system switches the refrigeration mode, the temperature difference between the inlet water temperature of the inlet water and the return air temperature of the load is often compared with the preset temperature threshold, and then the refrigeration mode after switching is determined. The preset temperature threshold is generally fixed based on the load state, if the preset temperature threshold is set based on the full load state, and the load in the machine room air conditioning system is in a low load state, the preset temperature threshold will not meet the heat exchange demand of the load, that is, the refrigeration mode after switching will not meet the heat exchange demand (refrigeration demand) of the load; At the same time, if the preset temperature threshold is set unreasonably, it will switch to the wrong refrigeration mode, resulting in repeated switching, which is not conducive to the stability of the machine room air conditioning system.

[0066] Therefore, the embodiment of the present application also provides a control method of a machine room air conditioning system, which can ensure that the refrigeration mode after switching meets the heat exchange demand of the load, and the refrigeration mode after switching does not need to be repeatedly switched, so that the machine room air conditioning system after switching can be quickly stabilized, and the stability of the machine room air conditioning system is improved. It can be understood that the control method is used to control the machine room air conditioning system described above, and the machine room air conditioning system will not be described here. The control method is as shown in Figure 3 The specific steps are as follows:

[0067] 301. Under the current cooling mode of the computer room air conditioning system, obtain the heat exchange of the surface cooler coil and the heat exchange of the evaporator coil.

[0068] In this embodiment, the cooling mode operated by the data center air conditioning system includes any one of the following: compressor cooling mode, natural cooling mode, and hybrid pre-cooling mode. Specifically, the compressor cooling mode involves the compressor cooling unit cooling the load; the natural cooling mode involves the natural cooling unit cooling the load; and the hybrid pre-cooling mode involves both the compressor cooling unit and the natural cooling unit cooling the load. Under the current cooling mode of the data center air conditioning system, the heat exchange of the surface cooler coil and the evaporator coil is obtained. Specifically, this can be achieved through... Figure 2 The inlet water temperature detector 104, outlet water temperature detector 105, and flow meter 106 in the natural cooling unit shown detect the heat exchange of the surface cooler coil, and the suction pressure detector 206, suction temperature detector 207, condensing pressure detector 208, and condensing temperature detector 209 in the compressor refrigeration unit detect the heat exchange of the evaporator coil.

[0069] 302. Compare the heat exchange capacity of the surface cooler coil and the evaporator coil with the heat exchange capacity required by the load in the computer room air conditioning system to determine the target cooling mode that meets the heat exchange capacity required by the load.

[0070] After obtaining the heat exchange capacity of the surface cooler coil and the evaporator coil, these values ​​can be compared with the heat exchange capacity required by the load in the computer room air conditioning system to determine the target cooling mode that meets the load's heat exchange requirements. The heat exchange capacity required by this load is the load's heat exchange demand (cooling demand). The required heat exchange capacity varies under different load conditions. For example, under full load, the load generates more heat, and therefore requires a higher heat exchange capacity; under low load, the load generates less heat, and therefore requires a lower heat exchange capacity. The required heat exchange capacity can be adjusted based on the load condition.

[0071] determining a target refrigeration mode satisfying the heat exchange amount required by the load, specifically, if the sum of the heat exchange amount of the table cooler coil and the heat exchange amount of the evaporating coil matches the heat exchange amount required by the load, and lasts for a first preset time length, it is determined that the target refrigeration mode is a mixed pre-cooling mode. Wherein, the heat exchange amount required by the load can be greater than or equal to the heat exchange amount required by the load, and the first preset time length can be any length in 60 seconds to 600 seconds, which is not limited here. That is, the sum of the heat exchange amount of the table cooler coil and the heat exchange amount of the evaporating coil is required to meet the heat exchange amount required by the load, at this time, the target refrigeration mode can be determined as: mixed pre-cooling mode, that is, the compressor refrigeration unit and the natural cooling unit are in action, and the load is cooled by heat exchange through the table cooler coil and the evaporating coil.

[0072] If the heat exchange amount of the table cooler coil matches the heat exchange amount required by the load and lasts for a second preset time length, the target refrigeration mode is determined to be a natural cooling mode. The second preset time length can be any length in 60 seconds to 600 seconds, which is not limited here. That is, only the heat exchange amount of the table cooler coil can meet the heat exchange amount required by the load, at this time, the target refrigeration mode can be determined as: natural cooling mode, that is, only the natural cooling unit is in action, and the load is cooled by heat exchange through the table cooler coil.

[0073] If the heat exchange amount of the evaporating coil matches the heat exchange amount required by the load and lasts for a third preset time length, the target refrigeration mode is determined to be a compressor refrigeration mode. The third preset time length can be any length in 60 seconds to 600 seconds, which is not limited here. It can be understood that the first preset time length, the second preset time length and the third preset time length can be the same length or different length, which is not limited here. That is, only the heat exchange amount of the evaporating coil can meet the heat exchange amount required by the load, at this time, the target refrigeration mode can be determined as: compressor refrigeration mode, that is, only the compressor refrigeration unit is in action, and the load is cooled by heat exchange through the evaporating coil.

[0074] It can be understood that if the heat exchange amount of the table cooler coil matches the heat exchange amount required by the load, and the heat exchange amount of the evaporating coil matches the heat exchange amount required by the load, preferably, the target refrigeration mode is determined to be a natural cooling mode, so as to save the power consumption of the compressor and effectively save energy.

[0075] 303、controlling the machine room air conditioning system to switch the currently running refrigeration mode to the target refrigeration mode.

[0076] When the target refrigeration mode is determined, the machine room air conditioning system can be controlled to automatically switch the currently running refrigeration mode to the target refrigeration mode. It can be understood that the currently running refrigeration mode can be automatically switched to the target refrigeration mode by controlling the compressor, the first valve, the second valve and the third valve in the machine room air conditioning system. Based on the difference of the refrigeration mode before switching, even if the target refrigeration mode after switching is the same, there is a difference in the switching control process. The refrigeration modes in which the machine room air conditioning system runs include: compressor refrigeration mode, natural cooling mode and mixed pre-cooling mode. These three refrigeration modes can be switched between each other at will. For example, the compressor refrigeration mode is directly switched to the natural cooling mode, that is, the compressor is controlled to be closed, the second end of the first valve is controlled to be opened, the second valve is controlled to be opened after the compressor is closed, and the third valve is controlled to be closed after the compressor is closed. Or, the natural cooling mode is switched to the compressor refrigeration mode, that is, the compressor is controlled to start running, the second end of the first valve is controlled to be closed, the second valve is controlled to be opened, and the third valve is controlled to be opened.

[0077] It can be seen that in the embodiments of the present application, the heat exchange capacity of the cooling coil and the heat exchange capacity of the evaporating coil are compared with the heat exchange capacity required by the load in the machine room air conditioning system to determine the target refrigeration mode that meets the heat exchange capacity required by the load. The refrigeration mode after switching can ensure that the heat exchange demand of the load is met, and the refrigeration mode after switching does not need to be switched repeatedly, so that the machine room air conditioning system can be quickly stabilized after switching, and the stability of the machine room air conditioning system is improved.

[0078] Further, the following will be combined with Figure 4 The control process of the machine room air conditioning system in the embodiments of the present application will be described in detail, and the specific steps are as follows:

[0079] 401, control the machine room air conditioning system to run in a refrigeration mode.

[0080] In the embodiments of the present application, when the load needs refrigeration, the machine room air conditioning system can be controlled to run in a refrigeration mode, wherein the refrigeration modes in which the machine room air conditioning system runs include: compressor refrigeration mode, natural cooling mode and mixed pre-cooling mode. The control of the machine room air conditioning system running in a refrigeration mode is specifically as follows: steps 4011 to 4013.

[0081] 4011, control the machine room air conditioning system to run in a compressor refrigeration mode.

[0082] When the operating mode of the machine room air conditioning system is the compressor refrigeration mode, the compressor is controlled to adjust the operating frequency based on the refrigeration demand of the load to adjust the supply air temperature of the evaporative coil to the load; that is, the higher the required refrigeration temperature of the load, the higher the frequency of the compressor, and the more refrigerant gas the high-frequency compressor can compress to reduce the supply air temperature of the evaporative coil to the load; the lower the required refrigeration temperature of the load, the lower the frequency of the compressor, and the less refrigerant gas the low-frequency compressor can compress to increase the supply air temperature of the evaporative coil to the load.

[0083] Meanwhile, the second end of the first valve (the first end and the third end of the first valve remain open) and the second valve can be controlled to be closed, and the third valve can be controlled to adjust the valve opening degree based on the temperature difference between the inlet water and the outlet water; the temperature difference between the inlet water of the inlet water end of the machine room air conditioning system and the outlet water of the outlet water end of the machine room air conditioning system; it can be understood that when the machine room air conditioning system operates in the compressor refrigeration mode, the temperature difference between the inlet water and the outlet water of the plate heat exchanger can be understood, the flow rate detected by the flow meter is the flow rate through the plate heat exchanger, and the heat exchange capacity of the plate heat exchanger = temperature difference between inlet water and outlet water * flow rate * specific heat capacity. In order to maintain the heat exchange capacity of the plate heat exchanger, the third valve can be adjusted by PID according to the temperature difference between the inlet water and the outlet water; if the temperature difference between the inlet water and the outlet water is large, the valve opening degree of the third valve needs to be increased to reduce the flow rate through the plate heat exchanger and maintain the heat exchange capacity of the plate heat exchanger; if the temperature difference between the inlet water and the outlet water is small, the valve opening degree of the third valve needs to be reduced to increase the flow rate through the plate heat exchanger and maintain the heat exchange capacity of the plate heat exchanger.

[0084] 4012、Control the machine room air conditioning system to operate in the natural cooling mode.

[0085] When the operating mode of the machine room air conditioning system is the natural cooling mode, the compressor is controlled to be closed, the second end of the first valve is controlled to be open (the second end of the first valve can be controlled to be fully open), the second valve is controlled to adjust the valve opening degree based on the supply air temperature of the cooling coil to the load, and the third valve is controlled to be closed. That is, by adjusting the valve opening degree of the second valve, the supply air temperature of the cooling coil to the load can be maintained, if the supply air temperature is too high, the valve opening degree of the second valve needs to be increased to increase the flow rate through the cooling coil to reduce the supply air temperature, and if the supply air temperature is too low, the valve opening degree of the second valve needs to be reduced to reduce the flow rate through the cooling coil to increase the supply air temperature.

[0086] 4013、Control the machine room air conditioning system to operate in the mixed precooling mode.

[0087] When the operation mode of the computer room air conditioning system is the mixed pre-cooling mode, the compressor adjusts the operation frequency based on the cooling demand of the load, the second end of the first valve is controlled to be open (the second end of the first valve can be controlled to be fully open), the second valve is controlled to be closed, and the third valve adjusts the valve opening degree based on the temperature difference between the inlet and outlet water. That is, when the mixed pre-cooling mode is operated, the compressor refrigeration unit and the natural cooling unit are simultaneously actuated, and the cooling coil and the evaporative coil simultaneously cool the load.

[0088] 402. In the current operation mode of the computer room air conditioning system, the heat exchange capacity of the cooling coil and the heat exchange capacity of the evaporative coil are obtained.

[0089] 403. The heat exchange capacity of the cooling coil and the heat exchange capacity of the evaporative coil are compared with the heat exchange capacity required by the load in the computer room air conditioning system to determine the target cooling mode that meets the heat exchange capacity required by the load.

[0090] It can be understood that steps 402 and 403 are similar to steps 301 and 302 described above, and will not be repeated here.

[0091] 404. Control the computer room air conditioning system to switch the current operation mode to the target cooling mode.

[0092] After determining the target cooling mode, the computer room air conditioning system can be controlled to switch the current operation mode to the target cooling mode; the specific steps are as follows:

[0093] 4041. Switch from the compressor cooling mode to the mixed pre-cooling mode.

[0094] If the current operation mode is the compressor cooling mode and the target cooling mode is the mixed pre-cooling mode, the second end of the first valve can be controlled to switch from closed to open, and other valves remain in the original state, so that the computer room air conditioning system is switched from the compressor cooling mode to the mixed pre-cooling mode.

[0095] 4042. Switch from the natural cooling mode to the mixed pre-cooling mode.

[0096] If the current running refrigeration mode is: natural cooling mode, and the target refrigeration mode is: mixed pre-cooling mode; the second end of the first valve can be controlled to remain open, the valve opening degree of the second valve can be controlled to gradually close to complete closure, and the valve opening degree of the third valve can be controlled to be adjusted based on the valve opening degree of the second valve and the temperature difference between the inlet and outlet water. The valve opening degree of the third valve can be controlled to be equal to the valve opening degree of the second valve plus a set opening degree value, which is determined based on the temperature difference between the inlet and outlet water. Based on the valve opening degree of the second valve and the temperature difference between the inlet and outlet water, the valve opening degree can be adjusted to adjust the cooling water flow into the plate heat exchanger and maintain the heat exchange capacity of the plate heat exchanger. After the third valve is opened, the compressor is started with a time delay to switch the machine room air conditioning system from the natural cooling mode to the mixed pre-cooling mode.

[0097] It can be understood that when the third valve corresponding to the water outlet on the plate heat exchanger is opened, the compressor is started with a time delay, and the time delay can be 0 to 120 seconds, which is not limited here. The high-temperature and high-pressure gaseous refrigerant compressed by the compressor can be condensed into low-temperature and low-pressure refrigerant gas through the cooling water flowing through the water inlet and outlet of the plate heat exchanger, avoiding the high-temperature and high-pressure refrigerant gas flowing into the evaporative coil, and ensuring the safety of the compressor refrigeration unit.

[0098] 4043, switching from mixed pre-cooling mode to natural cooling mode.

[0099] If the current running refrigeration mode is: mixed pre-cooling mode, and the target refrigeration mode is: natural cooling mode; the compressor can be controlled to be closed, the second valve can be controlled to be opened after the compressor is closed and delayed for a preset time, and the third valve can be controlled to be stepwise closed after the compressor is closed and delayed for a preset time, to switch the machine room air conditioning system from the mixed pre-cooling mode to the natural cooling mode. The preset time can be 0 to 300 seconds, which is not limited here. The second valve is controlled to be opened and the third valve is controlled to be closed after the compressor is closed and delayed for a preset time, i.e. switching to the natural cooling mode after the compressor is closed, to avoid the influence of the compressor not being closed on the operation of the natural cooling mode.

[0100] At the same time, the valve opening degree of the second valve is adjusted based on the temperature difference between the inlet and outlet water, which is the temperature difference between the inlet and outlet water of the cooling coil. By adjusting the valve opening degree of the second valve, the heat exchange capacity of the cooling coil can be adjusted during the switching process. If the temperature difference between the inlet and outlet water is too small, the valve opening degree of the second valve is increased, and the flow through the cooling coil is increased. If the temperature difference between the inlet and outlet water is too large, the valve opening degree of the second valve is decreased, and the flow through the cooling coil is decreased, to maintain the heat exchange capacity of the cooling coil consistent with the heat exchange capacity required by the load.

[0101] 4044, switching from mixed pre-cooling mode to compressor refrigeration mode.

[0102] If the current running refrigeration mode is the mixed pre-cooling mode and the target refrigeration mode is the compressor refrigeration mode, the second end of the first valve can be controlled to be closed, and the other valves remain to be in the original action, so as to switch the machine room air conditioning system from the mixed pre-cooling mode to the compressor refrigeration mode.

[0103] The embodiment of the present application further provides a computer readable storage medium, which comprises instructions, when the instructions are executed on a computer, the computer executes the control method as described above.

[0104] In the present application, the terms "first", "second", "third", "fourth" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance. The term "a plurality of" refers to two or more, unless otherwise explicitly limited.

[0105] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit them; although the foregoing embodiments of the present application are described in detail, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the description of the present application.

Claims

1. A control method of a machine room air conditioning system, characterized by, The machine room air conditioning system comprises a natural cooling unit and a compressor refrigeration unit, the natural cooling unit comprises a cooling coil, a first valve and a second valve, and the compressor refrigeration unit comprises a compressor, an evaporating coil, a plate heat exchanger, an electronic expansion valve and a third valve; wherein, the water inlet end of the machine room air conditioning system is connected with the input end of the cooling coil and the first end of the first valve respectively, the second end of the first valve is connected with the output end of the cooling coil, the third end of the first valve is connected with the water inlet of the plate heat exchanger and one end of the second valve respectively, the water outlet of the plate heat exchanger is connected with one end of the third valve, the other end of the third valve is connected with the other end of the second valve and the water outlet end of the machine room air conditioning system respectively, the output end of the evaporating coil is connected with the input end of the compressor, the output end of the compressor is connected with the input port of the plate heat exchanger, the output port of the plate heat exchanger is connected with one end of the electronic expansion valve, and the other end of the electronic expansion valve is connected with the input end of the evaporating coil; The control method comprises: In the current refrigeration mode of the machine room air conditioning system, the heat exchange amount of the cooling coil and the heat exchange amount of the evaporating coil are obtained; wherein, the refrigeration mode of the machine room air conditioning system comprises a compressor refrigeration mode, a natural cooling mode and a mixed pre-cooling mode; The heat exchange amount of the cooling coil and the heat exchange amount of the evaporating coil are compared with the heat exchange amount required by the load in the machine room air conditioning system to determine the target refrigeration mode that meets the heat exchange amount required by the load; The current refrigeration mode of the machine room air conditioning system is switched to the target refrigeration mode; When the refrigeration mode of the machine room air conditioning system is the compressor refrigeration mode, the compressor is controlled to adjust the operating frequency based on the refrigeration demand of the load to adjust the supply air temperature of the evaporating coil to the load, the second end of the first valve and the second valve are controlled to be closed, and the third valve is controlled to adjust the valve opening degree based on the temperature difference between the inlet and outlet water; When the refrigeration mode of the machine room air conditioning system is the natural cooling mode, the compressor is controlled to be closed, the second end of the first valve is controlled to be opened, the valve opening degree of the second valve is controlled based on the supply air temperature of the cooling coil to the load, and the third valve is controlled to be closed; When the refrigeration mode of the machine room air conditioning system is the mixed pre-cooling mode, the compressor is controlled to adjust the operating frequency based on the refrigeration demand of the load, the second end of the first valve is controlled to be opened, the second valve is controlled to be closed, and the third valve is controlled to adjust the valve opening degree based on the temperature difference between the inlet and outlet water.

2. The control method according to claim 1, characterized by, The natural cooling unit further comprises a water inlet temperature detector, a water outlet temperature detector and a flow meter; The water inlet temperature detector and the flow meter are arranged at the water inlet end of the machine room air conditioning system. The outlet water temperature detector is arranged at an outlet water end of the machine room air conditioning system.

3. The control method according to claim 1, characterized by, The compressor refrigeration unit further comprises a suction pressure detector, a suction temperature detector, a condensation pressure detector, and a condensation temperature detector. The suction pressure detector and the suction temperature detector are arranged between an output end of the evaporative coil and an input end of the compressor. The condensation pressure detector and the condensation temperature detector are arranged between an output port of the plate heat exchanger and the electronic expansion valve.

4. The control method according to claim 1, characterized by, The heat exchange amount of the surface cooler coil and the heat exchange amount of the evaporative coil are compared with the heat exchange amount required by the load in the machine room air conditioning system to determine a target refrigeration mode that meets the heat exchange amount required by the load, comprising: If the sum of the heat exchange amount of the surface cooler coil and the heat exchange amount of the evaporative coil matches the heat exchange amount required by the load and lasts for a first preset time, it is determined that the target refrigeration mode is a mixed pre-cooling mode. If the heat exchange amount of the surface cooler coil matches the heat exchange amount required by the load and lasts for a second preset time, it is determined that the target refrigeration mode is a natural cooling mode. If the heat exchange amount of the evaporative coil matches the heat exchange amount required by the load and lasts for a third preset time, it is determined that the target refrigeration mode is a compressor refrigeration mode.

5. The control method according to claim 1, characterized by, The current running refrigeration mode is a compressor refrigeration mode, and the target refrigeration mode is a mixed pre-cooling mode. The control of the machine room air conditioning system to switch the current running refrigeration mode to the target refrigeration mode comprises: Controlling the second end of the first valve to open to switch the machine room air conditioning system from the compressor refrigeration mode to the mixed pre-cooling mode.

6. The control method according to claim 1, characterized by, The current running refrigeration mode is a natural cooling mode, and the target refrigeration mode is a mixed pre-cooling mode. The control of the machine room air conditioning system to switch the current running refrigeration mode to the target refrigeration mode comprises: Controlling the valve opening degree of the second valve to gradually close to completely close, controlling the valve opening degree of the third valve based on the valve opening degree of the second valve and the inlet and outlet water temperature difference adjusting valve, and starting the compressor after the third valve is opened, to switch the machine room air conditioning system from the natural cooling mode to the mixed pre-cooling mode.

7. The control method according to claim 1, characterized by, The current running refrigeration mode is a mixed pre-cooling mode, and the target refrigeration mode is a natural cooling mode. The control of the machine room air conditioning system to switch the current running refrigeration mode to the target refrigeration mode comprises: Controlling the compressor to close, controlling the second valve to open after the compressor is closed and delayed for a preset time, and controlling the third valve to step close based on the inlet and outlet water temperature difference adjusting valve opening degree after the compressor is closed and delayed for a preset time, to switch the machine room air conditioning system from the mixed pre-cooling mode to the natural cooling mode.

8. The control method according to claim 1, characterized by, The current running refrigeration mode is a mixed pre-cooling mode, and the target refrigeration mode is a compressor refrigeration mode. The control of the machine room air conditioning system to switch the current running refrigeration mode to the target refrigeration mode comprises: controlling the second end of the first valve to close to switch the machine room air conditioning system from the mixed pre-cooling mode to the compressor refrigeration mode.

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